From ca3c508a028ff0b85d83619e320c8ab47bd9def0 Mon Sep 17 00:00:00 2001
From: aMannus <mannusmenting@gmail.com>
Date: Tue, 6 May 2025 13:17:14 +0200
Subject: [PATCH] apclientpp first attempt at dependencies

---
 .gitmodules                                   |    6 +
 soh/CMakeLists.txt                            |   17 +
 soh/soh/Network/Archipelago/Archipelago.cpp   |    2 +
 soh/soh/Network/Archipelago/Archipelago.h     |    1 +
 subprojects/apclientpp                        |    1 +
 subprojects/asio/COPYING                      |    4 +
 subprojects/asio/LICENSE_1_0.txt              |   23 +
 subprojects/asio/include/asio.hpp             |  152 +
 subprojects/asio/include/asio/COPYING         |    4 +
 subprojects/asio/include/asio/LICENSE_1_0.txt |   23 +
 .../include/asio/associated_allocator.hpp     |  131 +
 .../asio/include/asio/associated_executor.hpp |  149 +
 .../asio/include/asio/async_result.hpp        |  221 +
 .../include/asio/basic_datagram_socket.hpp    | 1040 +++++
 .../include/asio/basic_deadline_timer.hpp     |  628 +++
 .../asio/include/asio/basic_io_object.hpp     |  290 ++
 .../asio/include/asio/basic_raw_socket.hpp    | 1030 +++++
 .../include/asio/basic_seq_packet_socket.hpp  |  618 +++
 .../asio/include/asio/basic_serial_port.hpp   |  688 ++++
 .../asio/include/asio/basic_signal_set.hpp    |  391 ++
 .../asio/include/asio/basic_socket.hpp        | 1757 ++++++++
 .../include/asio/basic_socket_acceptor.hpp    | 1986 +++++++++
 .../include/asio/basic_socket_iostream.hpp    |  430 ++
 .../include/asio/basic_socket_streambuf.hpp   |  707 ++++
 .../asio/include/asio/basic_stream_socket.hpp |  921 +++++
 .../asio/include/asio/basic_streambuf.hpp     |  452 +++
 .../asio/include/asio/basic_streambuf_fwd.hpp |   36 +
 .../include/asio/basic_waitable_timer.hpp     |  705 ++++
 .../asio/include/asio/bind_executor.hpp       |  611 +++
 subprojects/asio/include/asio/buffer.hpp      | 2169 ++++++++++
 .../include/asio/buffered_read_stream.hpp     |  257 ++
 .../include/asio/buffered_read_stream_fwd.hpp |   25 +
 .../asio/include/asio/buffered_stream.hpp     |  278 ++
 .../asio/include/asio/buffered_stream_fwd.hpp |   25 +
 .../include/asio/buffered_write_stream.hpp    |  249 ++
 .../asio/buffered_write_stream_fwd.hpp        |   25 +
 .../asio/include/asio/buffers_iterator.hpp    |  521 +++
 .../include/asio/completion_condition.hpp     |  218 +
 subprojects/asio/include/asio/connect.hpp     | 1060 +++++
 subprojects/asio/include/asio/coroutine.hpp   |  328 ++
 .../include/asio/datagram_socket_service.hpp  |  466 +++
 .../asio/include/asio/deadline_timer.hpp      |   38 +
 .../include/asio/deadline_timer_service.hpp   |  173 +
 subprojects/asio/include/asio/defer.hpp       |  107 +
 .../asio/include/asio/detail/array.hpp        |   38 +
 .../asio/include/asio/detail/array_fwd.hpp    |   34 +
 .../asio/include/asio/detail/assert.hpp       |   32 +
 .../asio/include/asio/detail/atomic_count.hpp |   45 +
 .../asio/detail/base_from_completion_cond.hpp |   68 +
 .../asio/include/asio/detail/bind_handler.hpp |  816 ++++
 .../asio/detail/buffer_resize_guard.hpp       |   66 +
 .../asio/detail/buffer_sequence_adapter.hpp   |  544 +++
 .../asio/detail/buffered_stream_storage.hpp   |  126 +
 .../asio/include/asio/detail/call_stack.hpp   |  125 +
 .../asio/include/asio/detail/chrono.hpp       |   66 +
 .../asio/detail/chrono_time_traits.hpp        |  190 +
 .../asio/detail/completion_handler.hpp        |   83 +
 .../include/asio/detail/concurrency_hint.hpp  |   94 +
 .../detail/conditionally_enabled_event.hpp    |  112 +
 .../detail/conditionally_enabled_mutex.hpp    |  149 +
 .../asio/include/asio/detail/config.hpp       | 1456 +++++++
 .../include/asio/detail/consuming_buffers.hpp |  414 ++
 .../asio/include/asio/detail/cstddef.hpp      |   31 +
 .../asio/include/asio/detail/cstdint.hpp      |   60 +
 .../include/asio/detail/date_time_fwd.hpp     |   34 +
 .../asio/detail/deadline_timer_service.hpp    |  278 ++
 .../include/asio/detail/dependent_type.hpp    |   36 +
 .../include/asio/detail/descriptor_ops.hpp    |  121 +
 .../asio/detail/descriptor_read_op.hpp        |  128 +
 .../asio/detail/descriptor_write_op.hpp       |  128 +
 .../include/asio/detail/dev_poll_reactor.hpp  |  218 +
 .../include/asio/detail/epoll_reactor.hpp     |  266 ++
 .../asio/include/asio/detail/event.hpp        |   48 +
 .../detail/eventfd_select_interrupter.hpp     |   83 +
 .../asio/include/asio/detail/executor_op.hpp  |   84 +
 .../include/asio/detail/fd_set_adapter.hpp    |   39 +
 .../asio/include/asio/detail/fenced_block.hpp |   80 +
 .../asio/include/asio/detail/functional.hpp   |   38 +
 .../asio/include/asio/detail/future.hpp       |   33 +
 .../asio/detail/gcc_arm_fenced_block.hpp      |   91 +
 .../asio/detail/gcc_hppa_fenced_block.hpp     |   68 +
 .../asio/detail/gcc_sync_fenced_block.hpp     |   65 +
 .../asio/detail/gcc_x86_fenced_block.hpp      |   99 +
 .../asio/include/asio/detail/global.hpp       |   52 +
 .../asio/detail/handler_alloc_helpers.hpp     |  235 ++
 .../asio/detail/handler_cont_helpers.hpp      |   45 +
 .../asio/detail/handler_invoke_helpers.hpp    |   57 +
 .../include/asio/detail/handler_tracking.hpp  |  238 ++
 .../asio/detail/handler_type_requirements.hpp |  556 +++
 .../asio/include/asio/detail/handler_work.hpp |   95 +
 .../asio/include/asio/detail/hash_map.hpp     |  331 ++
 .../detail/impl/buffer_sequence_adapter.ipp   |  118 +
 .../asio/detail/impl/descriptor_ops.ipp       |  474 +++
 .../asio/detail/impl/dev_poll_reactor.hpp     |   91 +
 .../asio/detail/impl/dev_poll_reactor.ipp     |  446 ++
 .../asio/detail/impl/epoll_reactor.hpp        |   89 +
 .../asio/detail/impl/epoll_reactor.ipp        |  787 ++++
 .../impl/eventfd_select_interrupter.ipp       |  165 +
 .../asio/detail/impl/handler_tracking.ipp     |  358 ++
 .../asio/detail/impl/kqueue_reactor.hpp       |   93 +
 .../asio/detail/impl/kqueue_reactor.ipp       |  566 +++
 .../include/asio/detail/impl/null_event.ipp   |   74 +
 .../detail/impl/pipe_select_interrupter.ipp   |  124 +
 .../include/asio/detail/impl/posix_event.ipp  |   59 +
 .../include/asio/detail/impl/posix_mutex.ipp  |   46 +
 .../include/asio/detail/impl/posix_thread.ipp |   84 +
 .../asio/detail/impl/posix_tss_ptr.ipp        |   46 +
 .../impl/reactive_descriptor_service.ipp      |  222 +
 .../impl/reactive_serial_port_service.ipp     |  152 +
 .../impl/reactive_socket_service_base.ipp     |  300 ++
 .../detail/impl/resolver_service_base.ipp     |  154 +
 .../include/asio/detail/impl/scheduler.ipp    |  571 +++
 .../asio/detail/impl/select_reactor.hpp       |  100 +
 .../asio/detail/impl/select_reactor.ipp       |  333 ++
 .../asio/detail/impl/service_registry.hpp     |   94 +
 .../asio/detail/impl/service_registry.ipp     |  197 +
 .../asio/detail/impl/signal_set_service.ipp   |  669 +++
 .../include/asio/detail/impl/socket_ops.ipp   | 3571 +++++++++++++++++
 .../detail/impl/socket_select_interrupter.ipp |  176 +
 .../detail/impl/strand_executor_service.hpp   |  179 +
 .../detail/impl/strand_executor_service.ipp   |  134 +
 .../asio/detail/impl/strand_service.hpp       |  118 +
 .../asio/detail/impl/strand_service.ipp       |  177 +
 .../include/asio/detail/impl/throw_error.ipp  |   60 +
 .../asio/detail/impl/timer_queue_ptime.ipp    |   91 +
 .../asio/detail/impl/timer_queue_set.ipp      |  101 +
 .../include/asio/detail/impl/win_event.ipp    |   76 +
 .../detail/impl/win_iocp_handle_service.ipp   |  525 +++
 .../asio/detail/impl/win_iocp_io_context.hpp  |  103 +
 .../asio/detail/impl/win_iocp_io_context.ipp  |  554 +++
 .../impl/win_iocp_serial_port_service.ipp     |  181 +
 .../impl/win_iocp_socket_service_base.ipp     |  799 ++++
 .../include/asio/detail/impl/win_mutex.ipp    |   84 +
 .../detail/impl/win_object_handle_service.ipp |  449 +++
 .../asio/detail/impl/win_static_mutex.ipp     |  136 +
 .../include/asio/detail/impl/win_thread.ipp   |  150 +
 .../include/asio/detail/impl/win_tss_ptr.ipp  |   57 +
 .../impl/winrt_ssocket_service_base.ipp       |  629 +++
 .../detail/impl/winrt_timer_scheduler.hpp     |   92 +
 .../detail/impl/winrt_timer_scheduler.ipp     |  122 +
 .../include/asio/detail/impl/winsock_init.ipp |   82 +
 .../asio/include/asio/detail/io_control.hpp   |   84 +
 .../asio/detail/is_buffer_sequence.hpp        |  263 ++
 .../asio/include/asio/detail/is_executor.hpp  |  126 +
 .../include/asio/detail/keyword_tss_ptr.hpp   |   70 +
 .../include/asio/detail/kqueue_reactor.hpp    |  242 ++
 .../asio/include/asio/detail/limits.hpp       |   26 +
 .../asio/detail/local_free_on_block_exit.hpp  |   59 +
 .../asio/detail/macos_fenced_block.hpp        |   62 +
 .../asio/include/asio/detail/memory.hpp       |   70 +
 .../asio/include/asio/detail/mutex.hpp        |   48 +
 .../asio/include/asio/detail/noncopyable.hpp  |   43 +
 .../asio/include/asio/detail/null_event.hpp   |  100 +
 .../include/asio/detail/null_fenced_block.hpp |   47 +
 .../asio/include/asio/detail/null_global.hpp  |   59 +
 .../asio/include/asio/detail/null_mutex.hpp   |   64 +
 .../asio/include/asio/detail/null_reactor.hpp |   68 +
 .../asio/detail/null_signal_blocker.hpp       |   69 +
 .../asio/detail/null_socket_service.hpp       |  508 +++
 .../include/asio/detail/null_static_mutex.hpp |   60 +
 .../asio/include/asio/detail/null_thread.hpp  |   67 +
 .../asio/include/asio/detail/null_tss_ptr.hpp |   68 +
 .../asio/include/asio/detail/object_pool.hpp  |  171 +
 .../asio/detail/old_win_sdk_compat.hpp        |  214 +
 .../asio/include/asio/detail/op_queue.hpp     |  162 +
 .../asio/include/asio/detail/operation.hpp    |   38 +
 .../asio/detail/pipe_select_interrupter.hpp   |   89 +
 .../asio/include/asio/detail/pop_options.hpp  |  135 +
 .../asio/include/asio/detail/posix_event.hpp  |  162 +
 .../asio/detail/posix_fd_set_adapter.hpp      |  118 +
 .../asio/include/asio/detail/posix_global.hpp |   80 +
 .../asio/include/asio/detail/posix_mutex.hpp  |   76 +
 .../asio/detail/posix_signal_blocker.hpp      |   85 +
 .../asio/detail/posix_static_mutex.hpp        |   64 +
 .../asio/include/asio/detail/posix_thread.hpp |  109 +
 .../include/asio/detail/posix_tss_ptr.hpp     |   79 +
 .../asio/include/asio/detail/push_options.hpp |  175 +
 .../detail/reactive_descriptor_service.hpp    |  388 ++
 .../asio/detail/reactive_null_buffers_op.hpp  |   90 +
 .../detail/reactive_serial_port_service.hpp   |  236 ++
 .../asio/detail/reactive_socket_accept_op.hpp |  217 +
 .../detail/reactive_socket_connect_op.hpp     |  113 +
 .../asio/detail/reactive_socket_recv_op.hpp   |  135 +
 .../detail/reactive_socket_recvfrom_op.hpp    |  138 +
 .../detail/reactive_socket_recvmsg_op.hpp     |  132 +
 .../asio/detail/reactive_socket_send_op.hpp   |  134 +
 .../asio/detail/reactive_socket_sendto_op.hpp |  130 +
 .../asio/detail/reactive_socket_service.hpp   |  526 +++
 .../detail/reactive_socket_service_base.hpp   |  511 +++
 .../include/asio/detail/reactive_wait_op.hpp  |   90 +
 .../asio/include/asio/detail/reactor.hpp      |   32 +
 .../asio/include/asio/detail/reactor_fwd.hpp  |   40 +
 .../asio/include/asio/detail/reactor_op.hpp   |   65 +
 .../include/asio/detail/reactor_op_queue.hpp  |  168 +
 .../asio/detail/recycling_allocator.hpp       |  104 +
 .../asio/include/asio/detail/regex_fwd.hpp    |   35 +
 .../asio/detail/resolve_endpoint_op.hpp       |  122 +
 .../asio/include/asio/detail/resolve_op.hpp   |   45 +
 .../include/asio/detail/resolve_query_op.hpp  |  134 +
 .../include/asio/detail/resolver_service.hpp  |  145 +
 .../asio/detail/resolver_service_base.hpp     |  140 +
 .../asio/include/asio/detail/scheduler.hpp    |  213 +
 .../asio/detail/scheduler_operation.hpp       |   78 +
 .../asio/detail/scheduler_thread_info.hpp     |   40 +
 .../asio/include/asio/detail/scoped_lock.hpp  |  101 +
 .../asio/include/asio/detail/scoped_ptr.hpp   |   87 +
 .../asio/detail/select_interrupter.hpp        |   46 +
 .../include/asio/detail/select_reactor.hpp    |  238 ++
 .../include/asio/detail/service_registry.hpp  |  164 +
 .../include/asio/detail/signal_blocker.hpp    |   44 +
 .../include/asio/detail/signal_handler.hpp    |   86 +
 .../asio/include/asio/detail/signal_init.hpp  |   47 +
 .../asio/include/asio/detail/signal_op.hpp    |   49 +
 .../asio/detail/signal_set_service.hpp        |  217 +
 .../include/asio/detail/socket_holder.hpp     |   98 +
 .../asio/include/asio/detail/socket_ops.hpp   |  337 ++
 .../include/asio/detail/socket_option.hpp     |  316 ++
 .../asio/detail/socket_select_interrupter.hpp |   91 +
 .../asio/include/asio/detail/socket_types.hpp |  416 ++
 .../asio/detail/solaris_fenced_block.hpp      |   62 +
 .../asio/include/asio/detail/static_mutex.hpp |   52 +
 .../asio/include/asio/detail/std_event.hpp    |  176 +
 .../include/asio/detail/std_fenced_block.hpp  |   62 +
 .../asio/include/asio/detail/std_global.hpp   |   70 +
 .../asio/include/asio/detail/std_mutex.hpp    |   73 +
 .../include/asio/detail/std_static_mutex.hpp  |   81 +
 .../asio/include/asio/detail/std_thread.hpp   |   71 +
 .../asio/detail/strand_executor_service.hpp   |  142 +
 .../include/asio/detail/strand_service.hpp    |  142 +
 .../asio/include/asio/detail/string_view.hpp  |   47 +
 .../asio/include/asio/detail/thread.hpp       |   60 +
 .../include/asio/detail/thread_context.hpp    |   42 +
 .../asio/include/asio/detail/thread_group.hpp |   89 +
 .../include/asio/detail/thread_info_base.hpp  |  121 +
 .../asio/include/asio/detail/throw_error.hpp  |   53 +
 .../include/asio/detail/throw_exception.hpp   |   51 +
 .../asio/include/asio/detail/timer_queue.hpp  |  360 ++
 .../include/asio/detail/timer_queue_base.hpp  |   68 +
 .../include/asio/detail/timer_queue_ptime.hpp |   99 +
 .../include/asio/detail/timer_queue_set.hpp   |   66 +
 .../include/asio/detail/timer_scheduler.hpp   |   35 +
 .../asio/detail/timer_scheduler_fwd.hpp       |   40 +
 .../asio/include/asio/detail/tss_ptr.hpp      |   69 +
 .../asio/include/asio/detail/type_traits.hpp  |   86 +
 .../asio/detail/variadic_templates.hpp        |  119 +
 .../asio/include/asio/detail/wait_handler.hpp |   85 +
 .../asio/include/asio/detail/wait_op.hpp      |   45 +
 .../asio/include/asio/detail/win_event.hpp    |  151 +
 .../asio/detail/win_fd_set_adapter.hpp        |  149 +
 .../include/asio/detail/win_fenced_block.hpp  |   90 +
 .../asio/include/asio/detail/win_global.hpp   |   74 +
 .../asio/detail/win_iocp_handle_read_op.hpp   |  111 +
 .../asio/detail/win_iocp_handle_service.hpp   |  323 ++
 .../asio/detail/win_iocp_handle_write_op.hpp  |  103 +
 .../asio/detail/win_iocp_io_context.hpp       |  328 ++
 .../asio/detail/win_iocp_null_buffers_op.hpp  |  121 +
 .../asio/detail/win_iocp_operation.hpp        |   96 +
 .../asio/detail/win_iocp_overlapped_op.hpp    |   90 +
 .../asio/detail/win_iocp_overlapped_ptr.hpp   |  143 +
 .../detail/win_iocp_serial_port_service.hpp   |  230 ++
 .../asio/detail/win_iocp_socket_accept_op.hpp |  297 ++
 .../detail/win_iocp_socket_connect_op.hpp     |  127 +
 .../asio/detail/win_iocp_socket_recv_op.hpp   |  117 +
 .../detail/win_iocp_socket_recvfrom_op.hpp    |  125 +
 .../detail/win_iocp_socket_recvmsg_op.hpp     |  118 +
 .../asio/detail/win_iocp_socket_send_op.hpp   |  111 +
 .../asio/detail/win_iocp_socket_service.hpp   |  599 +++
 .../detail/win_iocp_socket_service_base.hpp   |  591 +++
 .../asio/detail/win_iocp_thread_info.hpp      |   34 +
 .../include/asio/detail/win_iocp_wait_op.hpp  |  121 +
 .../asio/include/asio/detail/win_mutex.hpp    |   78 +
 .../asio/detail/win_object_handle_service.hpp |  184 +
 .../include/asio/detail/win_static_mutex.hpp  |   74 +
 .../asio/include/asio/detail/win_thread.hpp   |  147 +
 .../asio/include/asio/detail/win_tss_ptr.hpp  |   79 +
 .../include/asio/detail/winapp_thread.hpp     |  124 +
 .../asio/include/asio/detail/wince_thread.hpp |  124 +
 .../asio/detail/winrt_async_manager.hpp       |  294 ++
 .../include/asio/detail/winrt_async_op.hpp    |   65 +
 .../include/asio/detail/winrt_resolve_op.hpp  |  118 +
 .../asio/detail/winrt_resolver_service.hpp    |  198 +
 .../asio/detail/winrt_socket_connect_op.hpp   |   92 +
 .../asio/detail/winrt_socket_recv_op.hpp      |  112 +
 .../asio/detail/winrt_socket_send_op.hpp      |  103 +
 .../asio/detail/winrt_ssocket_service.hpp     |  241 ++
 .../detail/winrt_ssocket_service_base.hpp     |  359 ++
 .../asio/detail/winrt_timer_scheduler.hpp     |  137 +
 .../asio/include/asio/detail/winrt_utils.hpp  |  106 +
 .../asio/include/asio/detail/winsock_init.hpp |  128 +
 .../include/asio/detail/work_dispatcher.hpp   |   72 +
 .../include/asio/detail/wrapped_handler.hpp   |  291 ++
 subprojects/asio/include/asio/dispatch.hpp    |  108 +
 subprojects/asio/include/asio/error.hpp       |  356 ++
 subprojects/asio/include/asio/error_code.hpp  |  202 +
 .../asio/include/asio/execution_context.hpp   |  411 ++
 subprojects/asio/include/asio/executor.hpp    |  341 ++
 .../asio/include/asio/executor_work_guard.hpp |  170 +
 .../asio/include/asio/experimental.hpp        |   22 +
 .../include/asio/experimental/co_spawn.hpp    |  226 ++
 .../include/asio/experimental/detached.hpp    |   65 +
 .../asio/experimental/impl/co_spawn.hpp       |  876 ++++
 .../asio/experimental/impl/detached.hpp       |   91 +
 .../asio/experimental/impl/redirect_error.hpp |  294 ++
 .../asio/experimental/redirect_error.hpp      |   67 +
 .../include/asio/generic/basic_endpoint.hpp   |  193 +
 .../asio/generic/datagram_protocol.hpp        |  123 +
 .../include/asio/generic/detail/endpoint.hpp  |  133 +
 .../asio/generic/detail/impl/endpoint.ipp     |  110 +
 .../include/asio/generic/raw_protocol.hpp     |  121 +
 .../asio/generic/seq_packet_protocol.hpp      |  122 +
 .../include/asio/generic/stream_protocol.hpp  |  127 +
 .../asio/include/asio/handler_alloc_hook.hpp  |   81 +
 .../asio/handler_continuation_hook.hpp        |   54 +
 .../asio/include/asio/handler_invoke_hook.hpp |   85 +
 .../asio/include/asio/handler_type.hpp        |   50 +
 .../include/asio/high_resolution_timer.hpp    |   44 +
 .../asio/impl/buffered_read_stream.hpp        |  429 ++
 .../asio/impl/buffered_write_stream.hpp       |  411 ++
 .../asio/include/asio/impl/connect.hpp        |  860 ++++
 subprojects/asio/include/asio/impl/defer.hpp  |   77 +
 .../asio/include/asio/impl/dispatch.hpp       |   78 +
 subprojects/asio/include/asio/impl/error.ipp  |  128 +
 .../asio/include/asio/impl/error_code.ipp     |  206 +
 .../include/asio/impl/execution_context.hpp   |  107 +
 .../include/asio/impl/execution_context.ipp   |   82 +
 .../asio/include/asio/impl/executor.hpp       |  386 ++
 .../asio/include/asio/impl/executor.ipp       |   38 +
 .../include/asio/impl/handler_alloc_hook.ipp  |   52 +
 .../asio/include/asio/impl/io_context.hpp     |  343 ++
 .../asio/include/asio/impl/io_context.ipp     |  174 +
 subprojects/asio/include/asio/impl/post.hpp   |   77 +
 subprojects/asio/include/asio/impl/read.hpp   |  715 ++++
 .../asio/include/asio/impl/read_at.hpp        |  640 +++
 .../asio/include/asio/impl/read_until.hpp     | 1502 +++++++
 .../include/asio/impl/serial_port_base.hpp    |   59 +
 .../include/asio/impl/serial_port_base.ipp    |  554 +++
 subprojects/asio/include/asio/impl/spawn.hpp  |  535 +++
 subprojects/asio/include/asio/impl/src.cpp    |   25 +
 subprojects/asio/include/asio/impl/src.hpp    |   82 +
 .../asio/include/asio/impl/system_context.hpp |   34 +
 .../asio/include/asio/impl/system_context.ipp |   73 +
 .../include/asio/impl/system_executor.hpp     |   85 +
 .../asio/include/asio/impl/thread_pool.hpp    |  127 +
 .../asio/include/asio/impl/thread_pool.ipp    |   76 +
 .../asio/include/asio/impl/use_future.hpp     |  937 +++++
 subprojects/asio/include/asio/impl/write.hpp  |  674 ++++
 .../asio/include/asio/impl/write_at.hpp       |  572 +++
 subprojects/asio/include/asio/io_context.hpp  |  876 ++++
 .../asio/include/asio/io_context_strand.hpp   |  384 ++
 subprojects/asio/include/asio/io_service.hpp  |   33 +
 .../asio/include/asio/io_service_strand.hpp   |   20 +
 subprojects/asio/include/asio/ip/address.hpp  |  260 ++
 .../asio/include/asio/ip/address_v4.hpp       |  329 ++
 .../include/asio/ip/address_v4_iterator.hpp   |  162 +
 .../asio/include/asio/ip/address_v4_range.hpp |  134 +
 .../asio/include/asio/ip/address_v6.hpp       |  336 ++
 .../include/asio/ip/address_v6_iterator.hpp   |  183 +
 .../asio/include/asio/ip/address_v6_range.hpp |  129 +
 .../asio/include/asio/ip/bad_address_cast.hpp |   53 +
 .../asio/include/asio/ip/basic_endpoint.hpp   |  263 ++
 .../asio/include/asio/ip/basic_resolver.hpp   | 1020 +++++
 .../include/asio/ip/basic_resolver_entry.hpp  |  113 +
 .../asio/ip/basic_resolver_iterator.hpp       |  192 +
 .../include/asio/ip/basic_resolver_query.hpp  |  244 ++
 .../asio/ip/basic_resolver_results.hpp        |  311 ++
 .../asio/include/asio/ip/detail/endpoint.hpp  |  139 +
 .../include/asio/ip/detail/impl/endpoint.ipp  |  199 +
 .../include/asio/ip/detail/socket_option.hpp  |  566 +++
 .../asio/include/asio/ip/host_name.hpp        |   42 +
 subprojects/asio/include/asio/ip/icmp.hpp     |  115 +
 .../asio/include/asio/ip/impl/address.hpp     |   67 +
 .../asio/include/asio/ip/impl/address.ipp     |  234 ++
 .../asio/include/asio/ip/impl/address_v4.hpp  |   67 +
 .../asio/include/asio/ip/impl/address_v4.ipp  |  210 +
 .../asio/include/asio/ip/impl/address_v6.hpp  |   67 +
 .../asio/include/asio/ip/impl/address_v6.ipp  |  350 ++
 .../include/asio/ip/impl/basic_endpoint.hpp   |   43 +
 .../asio/include/asio/ip/impl/host_name.ipp   |   54 +
 .../asio/include/asio/ip/impl/network_v4.hpp  |   54 +
 .../asio/include/asio/ip/impl/network_v4.ipp  |  216 +
 .../asio/include/asio/ip/impl/network_v6.hpp  |   53 +
 .../asio/include/asio/ip/impl/network_v6.ipp  |  185 +
 .../asio/include/asio/ip/multicast.hpp        |  191 +
 .../asio/include/asio/ip/network_v4.hpp       |  261 ++
 .../asio/include/asio/ip/network_v6.hpp       |  235 ++
 .../asio/include/asio/ip/resolver_base.hpp    |  129 +
 .../include/asio/ip/resolver_query_base.hpp   |   43 +
 .../asio/include/asio/ip/resolver_service.hpp |  200 +
 subprojects/asio/include/asio/ip/tcp.hpp      |  155 +
 subprojects/asio/include/asio/ip/udp.hpp      |  111 +
 subprojects/asio/include/asio/ip/unicast.hpp  |   70 +
 subprojects/asio/include/asio/ip/v6_only.hpp  |   69 +
 subprojects/asio/include/asio/is_executor.hpp |   46 +
 .../asio/include/asio/is_read_buffered.hpp    |   59 +
 .../asio/include/asio/is_write_buffered.hpp   |   59 +
 .../include/asio/local/basic_endpoint.hpp     |  239 ++
 .../asio/include/asio/local/connect_pair.hpp  |  106 +
 .../include/asio/local/datagram_protocol.hpp  |   80 +
 .../include/asio/local/detail/endpoint.hpp    |  133 +
 .../asio/local/detail/impl/endpoint.ipp       |  129 +
 .../include/asio/local/stream_protocol.hpp    |   90 +
 .../asio/include/asio/packaged_task.hpp       |  126 +
 .../asio/include/asio/placeholders.hpp        |  151 +
 .../include/asio/posix/basic_descriptor.hpp   |  582 +++
 .../asio/posix/basic_stream_descriptor.hpp    |  362 ++
 .../asio/include/asio/posix/descriptor.hpp    |  644 +++
 .../include/asio/posix/descriptor_base.hpp    |   90 +
 .../include/asio/posix/stream_descriptor.hpp  |  360 ++
 .../asio/posix/stream_descriptor_service.hpp  |  279 ++
 subprojects/asio/include/asio/post.hpp        |  107 +
 .../asio/include/asio/raw_socket_service.hpp  |  466 +++
 subprojects/asio/include/asio/read.hpp        |  947 +++++
 subprojects/asio/include/asio/read_at.hpp     |  671 ++++
 subprojects/asio/include/asio/read_until.hpp  | 1826 +++++++++
 .../asio/seq_packet_socket_service.hpp        |  416 ++
 subprojects/asio/include/asio/serial_port.hpp |  769 ++++
 .../asio/include/asio/serial_port_base.hpp    |  167 +
 .../asio/include/asio/serial_port_service.hpp |  249 ++
 subprojects/asio/include/asio/signal_set.hpp  |  447 +++
 .../asio/include/asio/signal_set_service.hpp  |  142 +
 .../include/asio/socket_acceptor_service.hpp  |  372 ++
 subprojects/asio/include/asio/socket_base.hpp |  559 +++
 subprojects/asio/include/asio/spawn.hpp       |  336 ++
 subprojects/asio/include/asio/ssl.hpp         |   27 +
 subprojects/asio/include/asio/ssl/context.hpp |  758 ++++
 .../asio/include/asio/ssl/context_base.hpp    |  209 +
 .../asio/ssl/detail/buffered_handshake_op.hpp |  114 +
 .../asio/include/asio/ssl/detail/engine.hpp   |  160 +
 .../include/asio/ssl/detail/handshake_op.hpp  |   62 +
 .../include/asio/ssl/detail/impl/engine.ipp   |  322 ++
 .../asio/ssl/detail/impl/openssl_init.ipp     |  165 +
 .../asio/include/asio/ssl/detail/io.hpp       |  372 ++
 .../include/asio/ssl/detail/openssl_init.hpp  |  101 +
 .../include/asio/ssl/detail/openssl_types.hpp |   30 +
 .../asio/ssl/detail/password_callback.hpp     |   66 +
 .../asio/include/asio/ssl/detail/read_op.hpp  |   67 +
 .../include/asio/ssl/detail/shutdown_op.hpp   |   54 +
 .../include/asio/ssl/detail/stream_core.hpp   |  134 +
 .../asio/ssl/detail/verify_callback.hpp       |   62 +
 .../asio/include/asio/ssl/detail/write_op.hpp |   67 +
 subprojects/asio/include/asio/ssl/error.hpp   |  111 +
 .../asio/include/asio/ssl/impl/context.hpp    |   67 +
 .../asio/include/asio/ssl/impl/context.ipp    | 1204 ++++++
 .../asio/include/asio/ssl/impl/error.ipp      |  100 +
 .../asio/ssl/impl/rfc2818_verification.ipp    |  160 +
 .../asio/include/asio/ssl/impl/src.hpp        |   28 +
 .../include/asio/ssl/rfc2818_verification.hpp |   94 +
 subprojects/asio/include/asio/ssl/stream.hpp  |  762 ++++
 .../asio/include/asio/ssl/stream_base.hpp     |   52 +
 .../asio/include/asio/ssl/verify_context.hpp  |   67 +
 .../asio/include/asio/ssl/verify_mode.hpp     |   63 +
 .../asio/include/asio/steady_timer.hpp        |   42 +
 subprojects/asio/include/asio/strand.hpp      |  286 ++
 .../include/asio/stream_socket_service.hpp    |  412 ++
 subprojects/asio/include/asio/streambuf.hpp   |   33 +
 .../asio/include/asio/system_context.hpp      |   78 +
 .../asio/include/asio/system_error.hpp        |  131 +
 .../asio/include/asio/system_executor.hpp     |  129 +
 .../asio/include/asio/system_timer.hpp        |   42 +
 subprojects/asio/include/asio/thread.hpp      |   92 +
 subprojects/asio/include/asio/thread_pool.hpp |  232 ++
 subprojects/asio/include/asio/time_traits.hpp |   86 +
 subprojects/asio/include/asio/ts/buffer.hpp   |   24 +
 subprojects/asio/include/asio/ts/executor.hpp |   35 +
 subprojects/asio/include/asio/ts/internet.hpp |   40 +
 .../asio/include/asio/ts/io_context.hpp       |   20 +
 subprojects/asio/include/asio/ts/net.hpp      |   26 +
 subprojects/asio/include/asio/ts/netfwd.hpp   |  197 +
 subprojects/asio/include/asio/ts/socket.hpp   |   27 +
 subprojects/asio/include/asio/ts/timer.hpp    |   26 +
 subprojects/asio/include/asio/unyield.hpp     |   21 +
 subprojects/asio/include/asio/use_future.hpp  |  160 +
 .../asio/include/asio/uses_executor.hpp       |   71 +
 subprojects/asio/include/asio/version.hpp     |   23 +
 subprojects/asio/include/asio/wait_traits.hpp |   56 +
 .../include/asio/waitable_timer_service.hpp   |  210 +
 .../include/asio/windows/basic_handle.hpp     |  273 ++
 .../asio/windows/basic_object_handle.hpp      |  182 +
 .../windows/basic_random_access_handle.hpp    |  376 ++
 .../asio/windows/basic_stream_handle.hpp      |  359 ++
 .../include/asio/windows/object_handle.hpp    |  381 ++
 .../asio/windows/object_handle_service.hpp    |  183 +
 .../asio/windows/overlapped_handle.hpp        |  331 ++
 .../include/asio/windows/overlapped_ptr.hpp   |  116 +
 .../asio/windows/random_access_handle.hpp     |  378 ++
 .../windows/random_access_handle_service.hpp  |  214 +
 .../include/asio/windows/stream_handle.hpp    |  362 ++
 .../asio/windows/stream_handle_service.hpp    |  210 +
 subprojects/asio/include/asio/write.hpp       |  928 +++++
 subprojects/asio/include/asio/write_at.hpp    |  679 ++++
 subprojects/asio/include/asio/yield.hpp       |   23 +
 subprojects/valijson/Authors                  |   38 +
 subprojects/valijson/LICENSE                  |   23 +
 .../valijson/include/compat/optional.hpp      | 1043 +++++
 .../include/valijson/adapters/adapter.hpp     |  472 +++
 .../valijson/adapters/basic_adapter.hpp       |  859 ++++
 .../valijson/adapters/frozen_value.hpp        |   52 +
 .../valijson/adapters/json11_adapter.hpp      |  711 ++++
 .../valijson/adapters/jsoncpp_adapter.hpp     |  724 ++++
 .../adapters/nlohmann_json_adapter.hpp        |  713 ++++
 .../valijson/adapters/picojson_adapter.hpp    |  732 ++++
 .../valijson/adapters/poco_json_adapter.hpp   |  720 ++++
 .../adapters/property_tree_adapter.hpp        |  753 ++++
 .../valijson/adapters/qtjson_adapter.hpp      |  722 ++++
 .../valijson/adapters/rapidjson_adapter.hpp   |  937 +++++
 .../valijson/adapters/std_string_adapter.hpp  |  491 +++
 .../include/valijson/constraint_builder.hpp   |   21 +
 .../valijson/constraints/basic_constraint.hpp |   55 +
 .../constraints/concrete_constraints.hpp      | 1247 ++++++
 .../valijson/constraints/constraint.hpp       |   50 +
 .../constraints/constraint_visitor.hpp        |  104 +
 .../valijson/include/valijson/exceptions.hpp  |   41 +
 .../valijson/internal/custom_allocator.hpp    |  107 +
 .../include/valijson/internal/debug.hpp       |   30 +
 .../valijson/internal/json_pointer.hpp        |  275 ++
 .../valijson/internal/json_reference.hpp      |   60 +
 .../include/valijson/internal/optional.hpp    |   14 +
 .../include/valijson/internal/uri.hpp         |   33 +
 .../valijson/include/valijson/schema.hpp      |  224 ++
 .../include/valijson/schema_parser.hpp        | 2282 +++++++++++
 .../valijson/include/valijson/subschema.hpp   |  311 ++
 .../include/valijson/utils/file_utils.hpp     |   44 +
 .../include/valijson/utils/json11_utils.hpp   |   34 +
 .../include/valijson/utils/jsoncpp_utils.hpp  |   35 +
 .../valijson/utils/nlohmann_json_utils.hpp    |   43 +
 .../include/valijson/utils/picojson_utils.hpp |   39 +
 .../valijson/utils/poco_json_utils.hpp        |   37 +
 .../valijson/utils/property_tree_utils.hpp    |   74 +
 .../include/valijson/utils/qtjson_utils.hpp   |   44 +
 .../valijson/utils/rapidjson_utils.hpp        |   46 +
 .../include/valijson/utils/utf8_utils.hpp     |   63 +
 .../include/valijson/validation_results.hpp   |  107 +
 .../include/valijson/validation_visitor.hpp   | 1792 +++++++++
 .../valijson/include/valijson/validator.hpp   |   77 +
 .../websocketpp/websocketpp/CMakeLists.txt    |    2 +
 subprojects/websocketpp/websocketpp/COPYING   |  145 +
 .../websocketpp/websocketpp/base64/base64.hpp |  178 +
 .../websocketpp/websocketpp/client.hpp        |   33 +
 subprojects/websocketpp/websocketpp/close.hpp |  353 ++
 .../websocketpp/websocketpp/common/asio.hpp   |  141 +
 .../websocketpp/common/asio_ssl.hpp           |   39 +
 .../websocketpp/websocketpp/common/chrono.hpp |   68 +
 .../websocketpp/common/connection_hdl.hpp     |   52 +
 .../websocketpp/websocketpp/common/cpp11.hpp  |  162 +
 .../websocketpp/common/functional.hpp         |  105 +
 .../websocketpp/websocketpp/common/md5.hpp    |  448 +++
 .../websocketpp/websocketpp/common/memory.hpp |   88 +
 .../websocketpp/common/network.hpp            |  106 +
 .../websocketpp/common/platforms.hpp          |   46 +
 .../websocketpp/websocketpp/common/random.hpp |   82 +
 .../websocketpp/websocketpp/common/regex.hpp  |   59 +
 .../websocketpp/websocketpp/common/stdint.hpp |   73 +
 .../websocketpp/common/system_error.hpp       |   84 +
 .../websocketpp/websocketpp/common/thread.hpp |   88 +
 .../websocketpp/websocketpp/common/time.hpp   |   56 +
 .../websocketpp/common/type_traits.hpp        |   65 +
 .../websocketpp/concurrency/basic.hpp         |   46 +
 .../websocketpp/concurrency/none.hpp          |   80 +
 .../websocketpp/websocketpp/config/asio.hpp   |   77 +
 .../websocketpp/config/asio_client.hpp        |   77 +
 .../websocketpp/config/asio_no_tls.hpp        |   73 +
 .../websocketpp/config/asio_no_tls_client.hpp |   73 +
 .../websocketpp/config/boost_config.hpp       |   72 +
 .../websocketpp/websocketpp/config/core.hpp   |  297 ++
 .../websocketpp/config/core_client.hpp        |  294 ++
 .../websocketpp/websocketpp/config/debug.hpp  |  286 ++
 .../websocketpp/config/debug_asio.hpp         |   77 +
 .../websocketpp/config/debug_asio_no_tls.hpp  |   73 +
 .../websocketpp/config/minimal_client.hpp     |   72 +
 .../websocketpp/config/minimal_server.hpp     |  312 ++
 .../websocketpp/websocketpp/connection.hpp    | 1642 ++++++++
 .../websocketpp/connection_base.hpp           |   38 +
 .../websocketpp/websocketpp/endpoint.hpp      |  700 ++++
 .../websocketpp/websocketpp/endpoint_base.hpp |   38 +
 subprojects/websocketpp/websocketpp/error.hpp |  277 ++
 .../websocketpp/extensions/extension.hpp      |  102 +
 .../permessage_deflate/disabled.hpp           |  129 +
 .../extensions/permessage_deflate/enabled.hpp |  817 ++++
 subprojects/websocketpp/websocketpp/frame.hpp |  864 ++++
 .../websocketpp/http/constants.hpp            |  308 ++
 .../websocketpp/http/impl/parser.hpp          |  200 +
 .../websocketpp/http/impl/request.hpp         |  191 +
 .../websocketpp/http/impl/response.hpp        |  266 ++
 .../websocketpp/websocketpp/http/parser.hpp   |  629 +++
 .../websocketpp/websocketpp/http/request.hpp  |  124 +
 .../websocketpp/websocketpp/http/response.hpp |  188 +
 .../websocketpp/impl/connection_impl.hpp      | 2375 +++++++++++
 .../websocketpp/impl/endpoint_impl.hpp        |  269 ++
 .../websocketpp/impl/utilities_impl.hpp       |   87 +
 .../websocketpp/websocketpp/logger/basic.hpp  |  199 +
 .../websocketpp/websocketpp/logger/levels.hpp |  203 +
 .../websocketpp/websocketpp/logger/stub.hpp   |  119 +
 .../websocketpp/websocketpp/logger/syslog.hpp |  146 +
 .../websocketpp/message_buffer/alloc.hpp      |  105 +
 .../websocketpp/message_buffer/message.hpp    |  340 ++
 .../websocketpp/message_buffer/pool.hpp       |  229 ++
 .../websocketpp/processors/base.hpp           |  299 ++
 .../websocketpp/processors/hybi00.hpp         |  462 +++
 .../websocketpp/processors/hybi07.hpp         |   78 +
 .../websocketpp/processors/hybi08.hpp         |   83 +
 .../websocketpp/processors/hybi13.hpp         | 1078 +++++
 .../websocketpp/processors/processor.hpp      |  407 ++
 .../websocketpp/websocketpp/random/none.hpp   |   60 +
 .../websocketpp/random/random_device.hpp      |   80 +
 .../websocketpp/roles/client_endpoint.hpp     |  173 +
 .../websocketpp/roles/server_endpoint.hpp     |  195 +
 .../websocketpp/websocketpp/server.hpp        |   33 +
 .../websocketpp/websocketpp/sha1/sha1.hpp     |  189 +
 .../websocketpp/transport/asio/base.hpp       |  232 ++
 .../websocketpp/transport/asio/connection.hpp | 1197 ++++++
 .../websocketpp/transport/asio/endpoint.hpp   | 1186 ++++++
 .../transport/asio/security/base.hpp          |  159 +
 .../transport/asio/security/none.hpp          |  373 ++
 .../transport/asio/security/tls.hpp           |  475 +++
 .../websocketpp/transport/base/connection.hpp |  238 ++
 .../websocketpp/transport/base/endpoint.hpp   |   77 +
 .../websocketpp/transport/iostream/base.hpp   |  133 +
 .../transport/iostream/connection.hpp         |  714 ++++
 .../transport/iostream/endpoint.hpp           |  222 +
 .../websocketpp/transport/stub/base.hpp       |   95 +
 .../websocketpp/transport/stub/connection.hpp |  286 ++
 .../websocketpp/transport/stub/endpoint.hpp   |  140 +
 subprojects/websocketpp/websocketpp/uri.hpp   |  356 ++
 .../websocketpp/utf8_validator.hpp            |  154 +
 .../websocketpp/websocketpp/utilities.hpp     |  180 +
 .../websocketpp/websocketpp/version.hpp       |   61 +
 subprojects/wswrap                            |    1 +
 627 files changed, 150875 insertions(+)
 create mode 100644 soh/soh/Network/Archipelago/Archipelago.cpp
 create mode 100644 soh/soh/Network/Archipelago/Archipelago.h
 create mode 160000 subprojects/apclientpp
 create mode 100644 subprojects/asio/COPYING
 create mode 100644 subprojects/asio/LICENSE_1_0.txt
 create mode 100644 subprojects/asio/include/asio.hpp
 create mode 100644 subprojects/asio/include/asio/COPYING
 create mode 100644 subprojects/asio/include/asio/LICENSE_1_0.txt
 create mode 100644 subprojects/asio/include/asio/associated_allocator.hpp
 create mode 100644 subprojects/asio/include/asio/associated_executor.hpp
 create mode 100644 subprojects/asio/include/asio/async_result.hpp
 create mode 100644 subprojects/asio/include/asio/basic_datagram_socket.hpp
 create mode 100644 subprojects/asio/include/asio/basic_deadline_timer.hpp
 create mode 100644 subprojects/asio/include/asio/basic_io_object.hpp
 create mode 100644 subprojects/asio/include/asio/basic_raw_socket.hpp
 create mode 100644 subprojects/asio/include/asio/basic_seq_packet_socket.hpp
 create mode 100644 subprojects/asio/include/asio/basic_serial_port.hpp
 create mode 100644 subprojects/asio/include/asio/basic_signal_set.hpp
 create mode 100644 subprojects/asio/include/asio/basic_socket.hpp
 create mode 100644 subprojects/asio/include/asio/basic_socket_acceptor.hpp
 create mode 100644 subprojects/asio/include/asio/basic_socket_iostream.hpp
 create mode 100644 subprojects/asio/include/asio/basic_socket_streambuf.hpp
 create mode 100644 subprojects/asio/include/asio/basic_stream_socket.hpp
 create mode 100644 subprojects/asio/include/asio/basic_streambuf.hpp
 create mode 100644 subprojects/asio/include/asio/basic_streambuf_fwd.hpp
 create mode 100644 subprojects/asio/include/asio/basic_waitable_timer.hpp
 create mode 100644 subprojects/asio/include/asio/bind_executor.hpp
 create mode 100644 subprojects/asio/include/asio/buffer.hpp
 create mode 100644 subprojects/asio/include/asio/buffered_read_stream.hpp
 create mode 100644 subprojects/asio/include/asio/buffered_read_stream_fwd.hpp
 create mode 100644 subprojects/asio/include/asio/buffered_stream.hpp
 create mode 100644 subprojects/asio/include/asio/buffered_stream_fwd.hpp
 create mode 100644 subprojects/asio/include/asio/buffered_write_stream.hpp
 create mode 100644 subprojects/asio/include/asio/buffered_write_stream_fwd.hpp
 create mode 100644 subprojects/asio/include/asio/buffers_iterator.hpp
 create mode 100644 subprojects/asio/include/asio/completion_condition.hpp
 create mode 100644 subprojects/asio/include/asio/connect.hpp
 create mode 100644 subprojects/asio/include/asio/coroutine.hpp
 create mode 100644 subprojects/asio/include/asio/datagram_socket_service.hpp
 create mode 100644 subprojects/asio/include/asio/deadline_timer.hpp
 create mode 100644 subprojects/asio/include/asio/deadline_timer_service.hpp
 create mode 100644 subprojects/asio/include/asio/defer.hpp
 create mode 100644 subprojects/asio/include/asio/detail/array.hpp
 create mode 100644 subprojects/asio/include/asio/detail/array_fwd.hpp
 create mode 100644 subprojects/asio/include/asio/detail/assert.hpp
 create mode 100644 subprojects/asio/include/asio/detail/atomic_count.hpp
 create mode 100644 subprojects/asio/include/asio/detail/base_from_completion_cond.hpp
 create mode 100644 subprojects/asio/include/asio/detail/bind_handler.hpp
 create mode 100644 subprojects/asio/include/asio/detail/buffer_resize_guard.hpp
 create mode 100644 subprojects/asio/include/asio/detail/buffer_sequence_adapter.hpp
 create mode 100644 subprojects/asio/include/asio/detail/buffered_stream_storage.hpp
 create mode 100644 subprojects/asio/include/asio/detail/call_stack.hpp
 create mode 100644 subprojects/asio/include/asio/detail/chrono.hpp
 create mode 100644 subprojects/asio/include/asio/detail/chrono_time_traits.hpp
 create mode 100644 subprojects/asio/include/asio/detail/completion_handler.hpp
 create mode 100644 subprojects/asio/include/asio/detail/concurrency_hint.hpp
 create mode 100644 subprojects/asio/include/asio/detail/conditionally_enabled_event.hpp
 create mode 100644 subprojects/asio/include/asio/detail/conditionally_enabled_mutex.hpp
 create mode 100644 subprojects/asio/include/asio/detail/config.hpp
 create mode 100644 subprojects/asio/include/asio/detail/consuming_buffers.hpp
 create mode 100644 subprojects/asio/include/asio/detail/cstddef.hpp
 create mode 100644 subprojects/asio/include/asio/detail/cstdint.hpp
 create mode 100644 subprojects/asio/include/asio/detail/date_time_fwd.hpp
 create mode 100644 subprojects/asio/include/asio/detail/deadline_timer_service.hpp
 create mode 100644 subprojects/asio/include/asio/detail/dependent_type.hpp
 create mode 100644 subprojects/asio/include/asio/detail/descriptor_ops.hpp
 create mode 100644 subprojects/asio/include/asio/detail/descriptor_read_op.hpp
 create mode 100644 subprojects/asio/include/asio/detail/descriptor_write_op.hpp
 create mode 100644 subprojects/asio/include/asio/detail/dev_poll_reactor.hpp
 create mode 100644 subprojects/asio/include/asio/detail/epoll_reactor.hpp
 create mode 100644 subprojects/asio/include/asio/detail/event.hpp
 create mode 100644 subprojects/asio/include/asio/detail/eventfd_select_interrupter.hpp
 create mode 100644 subprojects/asio/include/asio/detail/executor_op.hpp
 create mode 100644 subprojects/asio/include/asio/detail/fd_set_adapter.hpp
 create mode 100644 subprojects/asio/include/asio/detail/fenced_block.hpp
 create mode 100644 subprojects/asio/include/asio/detail/functional.hpp
 create mode 100644 subprojects/asio/include/asio/detail/future.hpp
 create mode 100644 subprojects/asio/include/asio/detail/gcc_arm_fenced_block.hpp
 create mode 100644 subprojects/asio/include/asio/detail/gcc_hppa_fenced_block.hpp
 create mode 100644 subprojects/asio/include/asio/detail/gcc_sync_fenced_block.hpp
 create mode 100644 subprojects/asio/include/asio/detail/gcc_x86_fenced_block.hpp
 create mode 100644 subprojects/asio/include/asio/detail/global.hpp
 create mode 100644 subprojects/asio/include/asio/detail/handler_alloc_helpers.hpp
 create mode 100644 subprojects/asio/include/asio/detail/handler_cont_helpers.hpp
 create mode 100644 subprojects/asio/include/asio/detail/handler_invoke_helpers.hpp
 create mode 100644 subprojects/asio/include/asio/detail/handler_tracking.hpp
 create mode 100644 subprojects/asio/include/asio/detail/handler_type_requirements.hpp
 create mode 100644 subprojects/asio/include/asio/detail/handler_work.hpp
 create mode 100644 subprojects/asio/include/asio/detail/hash_map.hpp
 create mode 100644 subprojects/asio/include/asio/detail/impl/buffer_sequence_adapter.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/descriptor_ops.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/dev_poll_reactor.hpp
 create mode 100644 subprojects/asio/include/asio/detail/impl/dev_poll_reactor.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/epoll_reactor.hpp
 create mode 100644 subprojects/asio/include/asio/detail/impl/epoll_reactor.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/eventfd_select_interrupter.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/handler_tracking.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/kqueue_reactor.hpp
 create mode 100644 subprojects/asio/include/asio/detail/impl/kqueue_reactor.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/null_event.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/pipe_select_interrupter.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/posix_event.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/posix_mutex.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/posix_thread.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/posix_tss_ptr.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/reactive_descriptor_service.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/reactive_serial_port_service.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/reactive_socket_service_base.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/resolver_service_base.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/scheduler.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/select_reactor.hpp
 create mode 100644 subprojects/asio/include/asio/detail/impl/select_reactor.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/service_registry.hpp
 create mode 100644 subprojects/asio/include/asio/detail/impl/service_registry.ipp
 create mode 100644 subprojects/asio/include/asio/detail/impl/signal_set_service.ipp
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 create mode 100644 subprojects/asio/include/asio/ts/executor.hpp
 create mode 100644 subprojects/asio/include/asio/ts/internet.hpp
 create mode 100644 subprojects/asio/include/asio/ts/io_context.hpp
 create mode 100644 subprojects/asio/include/asio/ts/net.hpp
 create mode 100644 subprojects/asio/include/asio/ts/netfwd.hpp
 create mode 100644 subprojects/asio/include/asio/ts/socket.hpp
 create mode 100644 subprojects/asio/include/asio/ts/timer.hpp
 create mode 100644 subprojects/asio/include/asio/unyield.hpp
 create mode 100644 subprojects/asio/include/asio/use_future.hpp
 create mode 100644 subprojects/asio/include/asio/uses_executor.hpp
 create mode 100644 subprojects/asio/include/asio/version.hpp
 create mode 100644 subprojects/asio/include/asio/wait_traits.hpp
 create mode 100644 subprojects/asio/include/asio/waitable_timer_service.hpp
 create mode 100644 subprojects/asio/include/asio/windows/basic_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/basic_object_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/basic_random_access_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/basic_stream_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/object_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/object_handle_service.hpp
 create mode 100644 subprojects/asio/include/asio/windows/overlapped_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/overlapped_ptr.hpp
 create mode 100644 subprojects/asio/include/asio/windows/random_access_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/random_access_handle_service.hpp
 create mode 100644 subprojects/asio/include/asio/windows/stream_handle.hpp
 create mode 100644 subprojects/asio/include/asio/windows/stream_handle_service.hpp
 create mode 100644 subprojects/asio/include/asio/write.hpp
 create mode 100644 subprojects/asio/include/asio/write_at.hpp
 create mode 100644 subprojects/asio/include/asio/yield.hpp
 create mode 100644 subprojects/valijson/Authors
 create mode 100644 subprojects/valijson/LICENSE
 create mode 100644 subprojects/valijson/include/compat/optional.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/basic_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/frozen_value.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/json11_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/jsoncpp_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/nlohmann_json_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/picojson_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/poco_json_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/property_tree_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/qtjson_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/rapidjson_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/adapters/std_string_adapter.hpp
 create mode 100644 subprojects/valijson/include/valijson/constraint_builder.hpp
 create mode 100644 subprojects/valijson/include/valijson/constraints/basic_constraint.hpp
 create mode 100644 subprojects/valijson/include/valijson/constraints/concrete_constraints.hpp
 create mode 100644 subprojects/valijson/include/valijson/constraints/constraint.hpp
 create mode 100644 subprojects/valijson/include/valijson/constraints/constraint_visitor.hpp
 create mode 100644 subprojects/valijson/include/valijson/exceptions.hpp
 create mode 100644 subprojects/valijson/include/valijson/internal/custom_allocator.hpp
 create mode 100644 subprojects/valijson/include/valijson/internal/debug.hpp
 create mode 100644 subprojects/valijson/include/valijson/internal/json_pointer.hpp
 create mode 100644 subprojects/valijson/include/valijson/internal/json_reference.hpp
 create mode 100644 subprojects/valijson/include/valijson/internal/optional.hpp
 create mode 100644 subprojects/valijson/include/valijson/internal/uri.hpp
 create mode 100644 subprojects/valijson/include/valijson/schema.hpp
 create mode 100644 subprojects/valijson/include/valijson/schema_parser.hpp
 create mode 100644 subprojects/valijson/include/valijson/subschema.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/file_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/json11_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/jsoncpp_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/nlohmann_json_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/picojson_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/poco_json_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/property_tree_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/qtjson_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/rapidjson_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/utils/utf8_utils.hpp
 create mode 100644 subprojects/valijson/include/valijson/validation_results.hpp
 create mode 100644 subprojects/valijson/include/valijson/validation_visitor.hpp
 create mode 100644 subprojects/valijson/include/valijson/validator.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/CMakeLists.txt
 create mode 100644 subprojects/websocketpp/websocketpp/COPYING
 create mode 100644 subprojects/websocketpp/websocketpp/base64/base64.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/client.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/close.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/asio.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/asio_ssl.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/chrono.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/connection_hdl.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/cpp11.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/functional.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/md5.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/memory.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/network.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/platforms.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/random.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/regex.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/stdint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/system_error.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/thread.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/time.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/common/type_traits.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/concurrency/basic.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/concurrency/none.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/asio.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/asio_client.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/asio_no_tls.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/asio_no_tls_client.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/boost_config.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/core.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/core_client.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/debug.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/debug_asio.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/debug_asio_no_tls.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/minimal_client.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/config/minimal_server.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/connection.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/connection_base.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/endpoint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/endpoint_base.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/error.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/extensions/extension.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/extensions/permessage_deflate/disabled.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/extensions/permessage_deflate/enabled.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/frame.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/http/constants.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/http/impl/parser.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/http/impl/request.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/http/impl/response.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/http/parser.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/http/request.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/http/response.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/impl/connection_impl.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/impl/endpoint_impl.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/impl/utilities_impl.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/logger/basic.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/logger/levels.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/logger/stub.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/logger/syslog.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/message_buffer/alloc.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/message_buffer/message.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/message_buffer/pool.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/processors/base.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/processors/hybi00.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/processors/hybi07.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/processors/hybi08.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/processors/hybi13.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/processors/processor.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/random/none.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/random/random_device.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/roles/client_endpoint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/roles/server_endpoint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/server.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/sha1/sha1.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/asio/base.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/asio/connection.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/asio/endpoint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/asio/security/base.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/asio/security/none.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/asio/security/tls.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/base/connection.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/base/endpoint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/iostream/base.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/iostream/connection.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/iostream/endpoint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/stub/base.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/stub/connection.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/transport/stub/endpoint.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/uri.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/utf8_validator.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/utilities.hpp
 create mode 100644 subprojects/websocketpp/websocketpp/version.hpp
 create mode 160000 subprojects/wswrap

diff --git a/.gitmodules b/.gitmodules
index 7098d9d08..955377530 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,9 @@
 [submodule "OTRExporter"]
 	path = OTRExporter
 	url = https://github.com/harbourmasters/OTRExporter
+[submodule "subprojects/wswrap"]
+	path = subprojects/wswrap
+	url = https://github.com/black-sliver/wswrap.git
+[submodule "subprojects/apclientpp"]
+	path = subprojects/apclientpp
+	url = https://github.com/black-sliver/apclientpp.git
diff --git a/soh/CMakeLists.txt b/soh/CMakeLists.txt
index 7277b2dfb..90fa3c363 100644
--- a/soh/CMakeLists.txt
+++ b/soh/CMakeLists.txt
@@ -300,6 +300,23 @@ else()
     message("Boost found in " ${Boost_INCLUDE_DIRS})
     set(BOOST-INCLUDE ${Boost_INCLUDE_DIRS})
 endif()
+
+################################################################################
+# apclientpp + dependencies
+################################################################################
+add_compile_definitions(ASIO_STANDALONE)
+
+# TEMPORARY
+add_compile_definitions(WSWRAP_NO_SSL)
+
+target_include_directories(${PROJECT_NAME} PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/../subprojects/asio/include
+    ${CMAKE_CURRENT_SOURCE_DIR}/../subprojects/websocketpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../subprojects/wswrap/include
+    ${CMAKE_CURRENT_SOURCE_DIR}/../subprojects/valijson/include
+    ${CMAKE_CURRENT_SOURCE_DIR}/../subprojects/apclientpp
+)
+
 ################################################################################
 # Compile definitions
 ################################################################################
diff --git a/soh/soh/Network/Archipelago/Archipelago.cpp b/soh/soh/Network/Archipelago/Archipelago.cpp
new file mode 100644
index 000000000..f322ee85c
--- /dev/null
+++ b/soh/soh/Network/Archipelago/Archipelago.cpp
@@ -0,0 +1,2 @@
+#include "Archipelago.h"
+#include <apclient.hpp>
diff --git a/soh/soh/Network/Archipelago/Archipelago.h b/soh/soh/Network/Archipelago/Archipelago.h
new file mode 100644
index 000000000..8b1378917
--- /dev/null
+++ b/soh/soh/Network/Archipelago/Archipelago.h
@@ -0,0 +1 @@
+
diff --git a/subprojects/apclientpp b/subprojects/apclientpp
new file mode 160000
index 000000000..4ab7ba634
--- /dev/null
+++ b/subprojects/apclientpp
@@ -0,0 +1 @@
+Subproject commit 4ab7ba634809459196f476d3a485ddb076d62565
diff --git a/subprojects/asio/COPYING b/subprojects/asio/COPYING
new file mode 100644
index 000000000..532cec6c8
--- /dev/null
+++ b/subprojects/asio/COPYING
@@ -0,0 +1,4 @@
+Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+
+Distributed under the Boost Software License, Version 1.0. (See accompanying
+file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
diff --git a/subprojects/asio/LICENSE_1_0.txt b/subprojects/asio/LICENSE_1_0.txt
new file mode 100644
index 000000000..36b7cd93c
--- /dev/null
+++ b/subprojects/asio/LICENSE_1_0.txt
@@ -0,0 +1,23 @@
+Boost Software License - Version 1.0 - August 17th, 2003
+
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/subprojects/asio/include/asio.hpp b/subprojects/asio/include/asio.hpp
new file mode 100644
index 000000000..3356df009
--- /dev/null
+++ b/subprojects/asio/include/asio.hpp
@@ -0,0 +1,152 @@
+//
+// asio.hpp
+// ~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_HPP
+#define ASIO_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/async_result.hpp"
+#include "asio/basic_datagram_socket.hpp"
+#include "asio/basic_deadline_timer.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/basic_raw_socket.hpp"
+#include "asio/basic_seq_packet_socket.hpp"
+#include "asio/basic_serial_port.hpp"
+#include "asio/basic_signal_set.hpp"
+#include "asio/basic_socket_acceptor.hpp"
+#include "asio/basic_socket_iostream.hpp"
+#include "asio/basic_socket_streambuf.hpp"
+#include "asio/basic_stream_socket.hpp"
+#include "asio/basic_streambuf.hpp"
+#include "asio/basic_waitable_timer.hpp"
+#include "asio/bind_executor.hpp"
+#include "asio/buffer.hpp"
+#include "asio/buffered_read_stream_fwd.hpp"
+#include "asio/buffered_read_stream.hpp"
+#include "asio/buffered_stream_fwd.hpp"
+#include "asio/buffered_stream.hpp"
+#include "asio/buffered_write_stream_fwd.hpp"
+#include "asio/buffered_write_stream.hpp"
+#include "asio/buffers_iterator.hpp"
+#include "asio/completion_condition.hpp"
+#include "asio/connect.hpp"
+#include "asio/coroutine.hpp"
+#include "asio/datagram_socket_service.hpp"
+#include "asio/deadline_timer_service.hpp"
+#include "asio/deadline_timer.hpp"
+#include "asio/defer.hpp"
+#include "asio/dispatch.hpp"
+#include "asio/error.hpp"
+#include "asio/error_code.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/executor.hpp"
+#include "asio/executor_work_guard.hpp"
+#include "asio/generic/basic_endpoint.hpp"
+#include "asio/generic/datagram_protocol.hpp"
+#include "asio/generic/raw_protocol.hpp"
+#include "asio/generic/seq_packet_protocol.hpp"
+#include "asio/generic/stream_protocol.hpp"
+#include "asio/handler_alloc_hook.hpp"
+#include "asio/handler_continuation_hook.hpp"
+#include "asio/handler_invoke_hook.hpp"
+#include "asio/handler_type.hpp"
+#include "asio/high_resolution_timer.hpp"
+#include "asio/io_context.hpp"
+#include "asio/io_context_strand.hpp"
+#include "asio/io_service.hpp"
+#include "asio/io_service_strand.hpp"
+#include "asio/ip/address.hpp"
+#include "asio/ip/address_v4.hpp"
+#include "asio/ip/address_v4_iterator.hpp"
+#include "asio/ip/address_v4_range.hpp"
+#include "asio/ip/address_v6.hpp"
+#include "asio/ip/address_v6_iterator.hpp"
+#include "asio/ip/address_v6_range.hpp"
+#include "asio/ip/bad_address_cast.hpp"
+#include "asio/ip/basic_endpoint.hpp"
+#include "asio/ip/basic_resolver.hpp"
+#include "asio/ip/basic_resolver_entry.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+#include "asio/ip/host_name.hpp"
+#include "asio/ip/icmp.hpp"
+#include "asio/ip/multicast.hpp"
+#include "asio/ip/resolver_base.hpp"
+#include "asio/ip/resolver_query_base.hpp"
+#include "asio/ip/resolver_service.hpp"
+#include "asio/ip/tcp.hpp"
+#include "asio/ip/udp.hpp"
+#include "asio/ip/unicast.hpp"
+#include "asio/ip/v6_only.hpp"
+#include "asio/is_executor.hpp"
+#include "asio/is_read_buffered.hpp"
+#include "asio/is_write_buffered.hpp"
+#include "asio/local/basic_endpoint.hpp"
+#include "asio/local/connect_pair.hpp"
+#include "asio/local/datagram_protocol.hpp"
+#include "asio/local/stream_protocol.hpp"
+#include "asio/packaged_task.hpp"
+#include "asio/placeholders.hpp"
+#include "asio/posix/basic_descriptor.hpp"
+#include "asio/posix/basic_stream_descriptor.hpp"
+#include "asio/posix/descriptor.hpp"
+#include "asio/posix/descriptor_base.hpp"
+#include "asio/posix/stream_descriptor.hpp"
+#include "asio/posix/stream_descriptor_service.hpp"
+#include "asio/post.hpp"
+#include "asio/raw_socket_service.hpp"
+#include "asio/read.hpp"
+#include "asio/read_at.hpp"
+#include "asio/read_until.hpp"
+#include "asio/seq_packet_socket_service.hpp"
+#include "asio/serial_port.hpp"
+#include "asio/serial_port_base.hpp"
+#include "asio/serial_port_service.hpp"
+#include "asio/signal_set.hpp"
+#include "asio/signal_set_service.hpp"
+#include "asio/socket_acceptor_service.hpp"
+#include "asio/socket_base.hpp"
+#include "asio/steady_timer.hpp"
+#include "asio/strand.hpp"
+#include "asio/stream_socket_service.hpp"
+#include "asio/streambuf.hpp"
+#include "asio/system_context.hpp"
+#include "asio/system_error.hpp"
+#include "asio/system_executor.hpp"
+#include "asio/system_timer.hpp"
+#include "asio/thread.hpp"
+#include "asio/thread_pool.hpp"
+#include "asio/time_traits.hpp"
+#include "asio/use_future.hpp"
+#include "asio/uses_executor.hpp"
+#include "asio/version.hpp"
+#include "asio/wait_traits.hpp"
+#include "asio/waitable_timer_service.hpp"
+#include "asio/windows/basic_handle.hpp"
+#include "asio/windows/basic_object_handle.hpp"
+#include "asio/windows/basic_random_access_handle.hpp"
+#include "asio/windows/basic_stream_handle.hpp"
+#include "asio/windows/object_handle.hpp"
+#include "asio/windows/object_handle_service.hpp"
+#include "asio/windows/overlapped_handle.hpp"
+#include "asio/windows/overlapped_ptr.hpp"
+#include "asio/windows/random_access_handle.hpp"
+#include "asio/windows/random_access_handle_service.hpp"
+#include "asio/windows/stream_handle.hpp"
+#include "asio/windows/stream_handle_service.hpp"
+#include "asio/write.hpp"
+#include "asio/write_at.hpp"
+
+#endif // ASIO_HPP
diff --git a/subprojects/asio/include/asio/COPYING b/subprojects/asio/include/asio/COPYING
new file mode 100644
index 000000000..532cec6c8
--- /dev/null
+++ b/subprojects/asio/include/asio/COPYING
@@ -0,0 +1,4 @@
+Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+
+Distributed under the Boost Software License, Version 1.0. (See accompanying
+file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
diff --git a/subprojects/asio/include/asio/LICENSE_1_0.txt b/subprojects/asio/include/asio/LICENSE_1_0.txt
new file mode 100644
index 000000000..36b7cd93c
--- /dev/null
+++ b/subprojects/asio/include/asio/LICENSE_1_0.txt
@@ -0,0 +1,23 @@
+Boost Software License - Version 1.0 - August 17th, 2003
+
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/subprojects/asio/include/asio/associated_allocator.hpp b/subprojects/asio/include/asio/associated_allocator.hpp
new file mode 100644
index 000000000..8b488bb34
--- /dev/null
+++ b/subprojects/asio/include/asio/associated_allocator.hpp
@@ -0,0 +1,131 @@
+//
+// associated_allocator.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_ASSOCIATED_ALLOCATOR_HPP
+#define ASIO_ASSOCIATED_ALLOCATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <memory>
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename>
+struct associated_allocator_check
+{
+  typedef void type;
+};
+
+template <typename T, typename E, typename = void>
+struct associated_allocator_impl
+{
+  typedef E type;
+
+  static type get(const T&, const E& e) ASIO_NOEXCEPT
+  {
+    return e;
+  }
+};
+
+template <typename T, typename E>
+struct associated_allocator_impl<T, E,
+  typename associated_allocator_check<typename T::allocator_type>::type>
+{
+  typedef typename T::allocator_type type;
+
+  static type get(const T& t, const E&) ASIO_NOEXCEPT
+  {
+    return t.get_allocator();
+  }
+};
+
+} // namespace detail
+
+/// Traits type used to obtain the allocator associated with an object.
+/**
+ * A program may specialise this traits type if the @c T template parameter in
+ * the specialisation is a user-defined type. The template parameter @c
+ * Allocator shall be a type meeting the Allocator requirements.
+ *
+ * Specialisations shall meet the following requirements, where @c t is a const
+ * reference to an object of type @c T, and @c a is an object of type @c
+ * Allocator.
+ *
+ * @li Provide a nested typedef @c type that identifies a type meeting the
+ * Allocator requirements.
+ *
+ * @li Provide a noexcept static member function named @c get, callable as @c
+ * get(t) and with return type @c type.
+ *
+ * @li Provide a noexcept static member function named @c get, callable as @c
+ * get(t,a) and with return type @c type.
+ */
+template <typename T, typename Allocator = std::allocator<void> >
+struct associated_allocator
+{
+  /// If @c T has a nested type @c allocator_type, <tt>T::allocator_type</tt>.
+  /// Otherwise @c Allocator.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef see_below type;
+#else // defined(GENERATING_DOCUMENTATION)
+  typedef typename detail::associated_allocator_impl<T, Allocator>::type type;
+#endif // defined(GENERATING_DOCUMENTATION)
+
+  /// If @c T has a nested type @c allocator_type, returns
+  /// <tt>t.get_allocator()</tt>. Otherwise returns @c a.
+  static type get(const T& t,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return detail::associated_allocator_impl<T, Allocator>::get(t, a);
+  }
+};
+
+/// Helper function to obtain an object's associated allocator.
+/**
+ * @returns <tt>associated_allocator<T>::get(t)</tt>
+ */
+template <typename T>
+inline typename associated_allocator<T>::type
+get_associated_allocator(const T& t) ASIO_NOEXCEPT
+{
+  return associated_allocator<T>::get(t);
+}
+
+/// Helper function to obtain an object's associated allocator.
+/**
+ * @returns <tt>associated_allocator<T, Allocator>::get(t, a)</tt>
+ */
+template <typename T, typename Allocator>
+inline typename associated_allocator<T, Allocator>::type
+get_associated_allocator(const T& t, const Allocator& a) ASIO_NOEXCEPT
+{
+  return associated_allocator<T, Allocator>::get(t, a);
+}
+
+#if defined(ASIO_HAS_ALIAS_TEMPLATES)
+
+template <typename T, typename Allocator = std::allocator<void> >
+using associated_allocator_t
+  = typename associated_allocator<T, Allocator>::type;
+
+#endif // defined(ASIO_HAS_ALIAS_TEMPLATES)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_ASSOCIATED_ALLOCATOR_HPP
diff --git a/subprojects/asio/include/asio/associated_executor.hpp b/subprojects/asio/include/asio/associated_executor.hpp
new file mode 100644
index 000000000..4c5c20788
--- /dev/null
+++ b/subprojects/asio/include/asio/associated_executor.hpp
@@ -0,0 +1,149 @@
+//
+// associated_executor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_ASSOCIATED_EXECUTOR_HPP
+#define ASIO_ASSOCIATED_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/is_executor.hpp"
+#include "asio/system_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename>
+struct associated_executor_check
+{
+  typedef void type;
+};
+
+template <typename T, typename E, typename = void>
+struct associated_executor_impl
+{
+  typedef E type;
+
+  static type get(const T&, const E& e) ASIO_NOEXCEPT
+  {
+    return e;
+  }
+};
+
+template <typename T, typename E>
+struct associated_executor_impl<T, E,
+  typename associated_executor_check<typename T::executor_type>::type>
+{
+  typedef typename T::executor_type type;
+
+  static type get(const T& t, const E&) ASIO_NOEXCEPT
+  {
+    return t.get_executor();
+  }
+};
+
+} // namespace detail
+
+/// Traits type used to obtain the executor associated with an object.
+/**
+ * A program may specialise this traits type if the @c T template parameter in
+ * the specialisation is a user-defined type. The template parameter @c
+ * Executor shall be a type meeting the Executor requirements.
+ *
+ * Specialisations shall meet the following requirements, where @c t is a const
+ * reference to an object of type @c T, and @c e is an object of type @c
+ * Executor.
+ *
+ * @li Provide a nested typedef @c type that identifies a type meeting the
+ * Executor requirements.
+ *
+ * @li Provide a noexcept static member function named @c get, callable as @c
+ * get(t) and with return type @c type.
+ *
+ * @li Provide a noexcept static member function named @c get, callable as @c
+ * get(t,e) and with return type @c type.
+ */
+template <typename T, typename Executor = system_executor>
+struct associated_executor
+{
+  /// If @c T has a nested type @c executor_type, <tt>T::executor_type</tt>.
+  /// Otherwise @c Executor.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef see_below type;
+#else // defined(GENERATING_DOCUMENTATION)
+  typedef typename detail::associated_executor_impl<T, Executor>::type type;
+#endif // defined(GENERATING_DOCUMENTATION)
+
+  /// If @c T has a nested type @c executor_type, returns
+  /// <tt>t.get_executor()</tt>. Otherwise returns @c ex.
+  static type get(const T& t,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return detail::associated_executor_impl<T, Executor>::get(t, ex);
+  }
+};
+
+/// Helper function to obtain an object's associated executor.
+/**
+ * @returns <tt>associated_executor<T>::get(t)</tt>
+ */
+template <typename T>
+inline typename associated_executor<T>::type
+get_associated_executor(const T& t) ASIO_NOEXCEPT
+{
+  return associated_executor<T>::get(t);
+}
+
+/// Helper function to obtain an object's associated executor.
+/**
+ * @returns <tt>associated_executor<T, Executor>::get(t, ex)</tt>
+ */
+template <typename T, typename Executor>
+inline typename associated_executor<T, Executor>::type
+get_associated_executor(const T& t, const Executor& ex,
+    typename enable_if<is_executor<
+      Executor>::value>::type* = 0) ASIO_NOEXCEPT
+{
+  return associated_executor<T, Executor>::get(t, ex);
+}
+
+/// Helper function to obtain an object's associated executor.
+/**
+ * @returns <tt>associated_executor<T, typename
+ * ExecutionContext::executor_type>::get(t, ctx.get_executor())</tt>
+ */
+template <typename T, typename ExecutionContext>
+inline typename associated_executor<T,
+  typename ExecutionContext::executor_type>::type
+get_associated_executor(const T& t, ExecutionContext& ctx,
+    typename enable_if<is_convertible<ExecutionContext&,
+      execution_context&>::value>::type* = 0) ASIO_NOEXCEPT
+{
+  return associated_executor<T,
+    typename ExecutionContext::executor_type>::get(t, ctx.get_executor());
+}
+
+#if defined(ASIO_HAS_ALIAS_TEMPLATES)
+
+template <typename T, typename Executor = system_executor>
+using associated_executor_t = typename associated_executor<T, Executor>::type;
+
+#endif // defined(ASIO_HAS_ALIAS_TEMPLATES)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_ASSOCIATED_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/async_result.hpp b/subprojects/asio/include/asio/async_result.hpp
new file mode 100644
index 000000000..18acdf20a
--- /dev/null
+++ b/subprojects/asio/include/asio/async_result.hpp
@@ -0,0 +1,221 @@
+//
+// async_result.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_ASYNC_RESULT_HPP
+#define ASIO_ASYNC_RESULT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/handler_type.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// An interface for customising the behaviour of an initiating function.
+/**
+ * The async_result traits class is used for determining:
+ *
+ * @li the concrete completion handler type to be called at the end of the
+ * asynchronous operation;
+ *
+ * @li the initiating function return type; and
+ *
+ * @li how the return value of the initiating function is obtained.
+ *
+ * The trait allows the handler and return types to be determined at the point
+ * where the specific completion handler signature is known.
+ *
+ * This template may be specialised for user-defined completion token types.
+ * The primary template assumes that the CompletionToken is the completion
+ * handler.
+ */
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+template <typename CompletionToken, typename Signature>
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+template <typename CompletionToken, typename Signature = void>
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+class async_result
+{
+public:
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+  /// The concrete completion handler type for the specific signature.
+  typedef CompletionToken completion_handler_type;
+
+  /// The return type of the initiating function.
+  typedef void return_type;
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+  // For backward compatibility, determine the concrete completion handler type
+  // by using the legacy handler_type trait.
+  typedef typename handler_type<CompletionToken, Signature>::type
+    completion_handler_type;
+
+  // For backward compatibility, determine the initiating function return type
+  // using the legacy single-parameter version of async_result.
+  typedef typename async_result<completion_handler_type>::type return_type;
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+
+  /// Construct an async result from a given handler.
+  /**
+   * When using a specalised async_result, the constructor has an opportunity
+   * to initialise some state associated with the completion handler, which is
+   * then returned from the initiating function.
+   */
+  explicit async_result(completion_handler_type& h)
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+    // No data members to initialise.
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+    : legacy_result_(h)
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+  {
+    (void)h;
+  }
+
+  /// Obtain the value to be returned from the initiating function.
+  return_type get()
+  {
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+    // Nothing to do.
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+    return legacy_result_.get();
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+  }
+
+private:
+  async_result(const async_result&) ASIO_DELETED;
+  async_result& operator=(const async_result&) ASIO_DELETED;
+
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+  // No data members.
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+  async_result<completion_handler_type> legacy_result_;
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+/// (Deprecated: Use two-parameter version of async_result.) An interface for
+/// customising the behaviour of an initiating function.
+/**
+ * This template may be specialised for user-defined handler types.
+ */
+template <typename Handler>
+class async_result<Handler>
+{
+public:
+  /// The return type of the initiating function.
+  typedef void type;
+
+  /// Construct an async result from a given handler.
+  /**
+   * When using a specalised async_result, the constructor has an opportunity
+   * to initialise some state associated with the handler, which is then
+   * returned from the initiating function.
+   */
+  explicit async_result(Handler&)
+  {
+  }
+
+  /// Obtain the value to be returned from the initiating function.
+  type get()
+  {
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Helper template to deduce the handler type from a CompletionToken, capture
+/// a local copy of the handler, and then create an async_result for the
+/// handler.
+template <typename CompletionToken, typename Signature>
+struct async_completion
+{
+  /// The real handler type to be used for the asynchronous operation.
+  typedef typename asio::async_result<
+    typename decay<CompletionToken>::type,
+      Signature>::completion_handler_type completion_handler_type;
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Constructor.
+  /**
+   * The constructor creates the concrete completion handler and makes the link
+   * between the handler and the asynchronous result.
+   */
+  explicit async_completion(CompletionToken& token)
+    : completion_handler(static_cast<typename conditional<
+        is_same<CompletionToken, completion_handler_type>::value,
+        completion_handler_type&, CompletionToken&&>::type>(token)),
+      result(completion_handler)
+  {
+  }
+#else // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  explicit async_completion(typename decay<CompletionToken>::type& token)
+    : completion_handler(token),
+      result(completion_handler)
+  {
+  }
+
+  explicit async_completion(const typename decay<CompletionToken>::type& token)
+    : completion_handler(token),
+      result(completion_handler)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// A copy of, or reference to, a real handler object.
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  typename conditional<
+    is_same<CompletionToken, completion_handler_type>::value,
+    completion_handler_type&, completion_handler_type>::type completion_handler;
+#else // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  completion_handler_type completion_handler;
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// The result of the asynchronous operation's initiating function.
+  async_result<typename decay<CompletionToken>::type, Signature> result;
+};
+
+namespace detail {
+
+template <typename CompletionToken, typename Signature>
+struct async_result_helper
+  : async_result<typename decay<CompletionToken>::type, Signature>
+{
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(GENERATING_DOCUMENTATION)
+# define ASIO_INITFN_RESULT_TYPE(ct, sig) \
+  void_or_deduced
+#elif defined(_MSC_VER) && (_MSC_VER < 1500)
+# define ASIO_INITFN_RESULT_TYPE(ct, sig) \
+  typename ::asio::detail::async_result_helper< \
+    ct, sig>::return_type
+#define ASIO_HANDLER_TYPE(ct, sig) \
+  typename ::asio::detail::async_result_helper< \
+    ct, sig>::completion_handler_type
+#else
+# define ASIO_INITFN_RESULT_TYPE(ct, sig) \
+  typename ::asio::async_result< \
+    typename ::asio::decay<ct>::type, sig>::return_type
+#define ASIO_HANDLER_TYPE(ct, sig) \
+  typename ::asio::async_result< \
+    typename ::asio::decay<ct>::type, sig>::completion_handler_type
+#endif
+
+#endif // ASIO_ASYNC_RESULT_HPP
diff --git a/subprojects/asio/include/asio/basic_datagram_socket.hpp b/subprojects/asio/include/asio/basic_datagram_socket.hpp
new file mode 100644
index 000000000..346cc353f
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_datagram_socket.hpp
@@ -0,0 +1,1040 @@
+//
+// basic_datagram_socket.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_DATAGRAM_SOCKET_HPP
+#define ASIO_BASIC_DATAGRAM_SOCKET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/basic_socket.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/datagram_socket_service.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides datagram-oriented socket functionality.
+/**
+ * The basic_datagram_socket class template provides asynchronous and blocking
+ * datagram-oriented socket functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= datagram_socket_service<Protocol>)>
+class basic_datagram_socket
+  : public basic_socket<Protocol ASIO_SVC_TARG>
+{
+public:
+  /// The native representation of a socket.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename basic_socket<
+    Protocol ASIO_SVC_TARG>::native_handle_type native_handle_type;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  /// Construct a basic_datagram_socket without opening it.
+  /**
+   * This constructor creates a datagram socket without opening it. The open()
+   * function must be called before data can be sent or received on the socket.
+   *
+   * @param io_context The io_context object that the datagram socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   */
+  explicit basic_datagram_socket(asio::io_context& io_context)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context)
+  {
+  }
+
+  /// Construct and open a basic_datagram_socket.
+  /**
+   * This constructor creates and opens a datagram socket.
+   *
+   * @param io_context The io_context object that the datagram socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_datagram_socket(asio::io_context& io_context,
+      const protocol_type& protocol)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, protocol)
+  {
+  }
+
+  /// Construct a basic_datagram_socket, opening it and binding it to the given
+  /// local endpoint.
+  /**
+   * This constructor creates a datagram socket and automatically opens it bound
+   * to the specified endpoint on the local machine. The protocol used is the
+   * protocol associated with the given endpoint.
+   *
+   * @param io_context The io_context object that the datagram socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   *
+   * @param endpoint An endpoint on the local machine to which the datagram
+   * socket will be bound.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_datagram_socket(asio::io_context& io_context,
+      const endpoint_type& endpoint)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, endpoint)
+  {
+  }
+
+  /// Construct a basic_datagram_socket on an existing native socket.
+  /**
+   * This constructor creates a datagram socket object to hold an existing
+   * native socket.
+   *
+   * @param io_context The io_context object that the datagram socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @param native_socket The new underlying socket implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_datagram_socket(asio::io_context& io_context,
+      const protocol_type& protocol, const native_handle_type& native_socket)
+    : basic_socket<Protocol ASIO_SVC_TARG>(
+        io_context, protocol, native_socket)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_datagram_socket from another.
+  /**
+   * This constructor moves a datagram socket from one object to another.
+   *
+   * @param other The other basic_datagram_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_datagram_socket(io_context&) constructor.
+   */
+  basic_datagram_socket(basic_datagram_socket&& other)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_datagram_socket from another.
+  /**
+   * This assignment operator moves a datagram socket from one object to
+   * another.
+   *
+   * @param other The other basic_datagram_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_datagram_socket(io_context&) constructor.
+   */
+  basic_datagram_socket& operator=(basic_datagram_socket&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+
+  /// Move-construct a basic_datagram_socket from a socket of another protocol
+  /// type.
+  /**
+   * This constructor moves a datagram socket from one object to another.
+   *
+   * @param other The other basic_datagram_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_datagram_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  basic_datagram_socket(
+      basic_datagram_socket<Protocol1 ASIO_SVC_TARG1>&& other,
+      typename enable_if<is_convertible<Protocol1, Protocol>::value>::type* = 0)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_datagram_socket from a socket of another protocol
+  /// type.
+  /**
+   * This assignment operator moves a datagram socket from one object to
+   * another.
+   *
+   * @param other The other basic_datagram_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_datagram_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  typename enable_if<is_convertible<Protocol1, Protocol>::value,
+      basic_datagram_socket>::type& operator=(
+        basic_datagram_socket<Protocol1 ASIO_SVC_TARG1>&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the socket.
+  /**
+   * This function destroys the socket, cancelling any outstanding asynchronous
+   * operations associated with the socket as if by calling @c cancel.
+   */
+  ~basic_datagram_socket()
+  {
+  }
+
+  /// Send some data on a connected socket.
+  /**
+   * This function is used to send data on the datagram socket. The function
+   * call will block until the data has been sent successfully or an error
+   * occurs.
+   *
+   * @param buffers One ore more data buffers to be sent on the socket.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The send operation can only be used with a connected socket. Use
+   * the send_to function to send data on an unconnected datagram socket.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code socket.send(asio::buffer(data, size)); @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "send");
+    return s;
+  }
+
+  /// Send some data on a connected socket.
+  /**
+   * This function is used to send data on the datagram socket. The function
+   * call will block until the data has been sent successfully or an error
+   * occurs.
+   *
+   * @param buffers One ore more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The send operation can only be used with a connected socket. Use
+   * the send_to function to send data on an unconnected datagram socket.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+    asio::detail::throw_error(ec, "send");
+    return s;
+  }
+
+  /// Send some data on a connected socket.
+  /**
+   * This function is used to send data on the datagram socket. The function
+   * call will block until the data has been sent successfully or an error
+   * occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @note The send operation can only be used with a connected socket. Use
+   * the send_to function to send data on an unconnected datagram socket.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send on a connected socket.
+  /**
+   * This function is used to asynchronously send data on the datagram socket.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent on the socket. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * memory blocks is retained by the caller, which must guarantee that they
+   * remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_send operation can only be used with a connected socket.
+   * Use the async_send_to function to send data on an unconnected datagram
+   * socket.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.async_send(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(this->get_implementation(),
+        buffers, 0, ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(this->get_implementation(),
+        buffers, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous send on a connected socket.
+  /**
+   * This function is used to asynchronously send data on the datagram socket.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent on the socket. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * memory blocks is retained by the caller, which must guarantee that they
+   * remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_send operation can only be used with a connected socket.
+   * Use the async_send_to function to send data on an unconnected datagram
+   * socket.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(this->get_implementation(),
+        buffers, flags, ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(this->get_implementation(),
+        buffers, flags, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Send a datagram to the specified endpoint.
+  /**
+   * This function is used to send a datagram to the specified remote endpoint.
+   * The function call will block until the data has been sent successfully or
+   * an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * asio::ip::udp::endpoint destination(
+   *     asio::ip::address::from_string("1.2.3.4"), 12345);
+   * socket.send_to(asio::buffer(data, size), destination);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send_to(
+        this->get_implementation(), buffers, destination, 0, ec);
+    asio::detail::throw_error(ec, "send_to");
+    return s;
+  }
+
+  /// Send a datagram to the specified endpoint.
+  /**
+   * This function is used to send a datagram to the specified remote endpoint.
+   * The function call will block until the data has been sent successfully or
+   * an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send_to(
+        this->get_implementation(), buffers, destination, flags, ec);
+    asio::detail::throw_error(ec, "send_to");
+    return s;
+  }
+
+  /// Send a datagram to the specified endpoint.
+  /**
+   * This function is used to send a datagram to the specified remote endpoint.
+   * The function call will block until the data has been sent successfully or
+   * an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes sent.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    return this->get_service().send_to(this->get_implementation(),
+        buffers, destination, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  /**
+   * This function is used to asynchronously send a datagram to the specified
+   * remote endpoint. The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   * Copies will be made of the endpoint as required.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * asio::ip::udp::endpoint destination(
+   *     asio::ip::address::from_string("1.2.3.4"), 12345);
+   * socket.async_send_to(
+   *     asio::buffer(data, size), destination, handler);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send_to(
+        this->get_implementation(), buffers, destination, 0,
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send_to(
+        this->get_implementation(), buffers, destination, 0,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous send.
+  /**
+   * This function is used to asynchronously send a datagram to the specified
+   * remote endpoint. The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   * Copies will be made of the endpoint as required.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send_to(
+        this->get_implementation(), buffers, destination, flags,
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send_to(
+        this->get_implementation(), buffers, destination, flags,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the datagram socket. The function
+   * call will block until data has been received successfully or an error
+   * occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The receive operation can only be used with a connected socket. Use
+   * the receive_from function to receive data on an unconnected datagram
+   * socket.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code socket.receive(asio::buffer(data, size)); @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the datagram socket. The function
+   * call will block until data has been received successfully or an error
+   * occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The receive operation can only be used with a connected socket. Use
+   * the receive_from function to receive data on an unconnected datagram
+   * socket.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, flags, ec);
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the datagram socket. The function
+   * call will block until data has been received successfully or an error
+   * occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes received.
+   *
+   * @note The receive operation can only be used with a connected socket. Use
+   * the receive_from function to receive data on an unconnected datagram
+   * socket.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return this->get_service().receive(
+        this->get_implementation(), buffers, flags, ec);
+  }
+
+  /// Start an asynchronous receive on a connected socket.
+  /**
+   * This function is used to asynchronously receive data from the datagram
+   * socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_receive operation can only be used with a connected socket.
+   * Use the async_receive_from function to receive data on an unconnected
+   * datagram socket.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.async_receive(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous receive on a connected socket.
+  /**
+   * This function is used to asynchronously receive data from the datagram
+   * socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_receive operation can only be used with a connected socket.
+   * Use the async_receive_from function to receive data on an unconnected
+   * datagram socket.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(this->get_implementation(),
+        buffers, flags, ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive(this->get_implementation(),
+        buffers, flags, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Receive a datagram with the endpoint of the sender.
+  /**
+   * This function is used to receive a datagram. The function call will block
+   * until data has been received successfully or an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the datagram.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * asio::ip::udp::endpoint sender_endpoint;
+   * socket.receive_from(
+   *     asio::buffer(data, size), sender_endpoint);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive_from(
+        this->get_implementation(), buffers, sender_endpoint, 0, ec);
+    asio::detail::throw_error(ec, "receive_from");
+    return s;
+  }
+  
+  /// Receive a datagram with the endpoint of the sender.
+  /**
+   * This function is used to receive a datagram. The function call will block
+   * until data has been received successfully or an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the datagram.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive_from(
+        this->get_implementation(), buffers, sender_endpoint, flags, ec);
+    asio::detail::throw_error(ec, "receive_from");
+    return s;
+  }
+  
+  /// Receive a datagram with the endpoint of the sender.
+  /**
+   * This function is used to receive a datagram. The function call will block
+   * until data has been received successfully or an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the datagram.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes received.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    return this->get_service().receive_from(this->get_implementation(),
+        buffers, sender_endpoint, flags, ec);
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive a datagram. The function
+   * call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the datagram. Ownership of the sender_endpoint object
+   * is retained by the caller, which must guarantee that it is valid until the
+   * handler is called.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code socket.async_receive_from(
+   *     asio::buffer(data, size), sender_endpoint, handler); @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, 0,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, 0,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive a datagram. The function
+   * call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the datagram. Ownership of the sender_endpoint object
+   * is retained by the caller, which must guarantee that it is valid until the
+   * handler is called.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, flags,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, flags,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BASIC_DATAGRAM_SOCKET_HPP
diff --git a/subprojects/asio/include/asio/basic_deadline_timer.hpp b/subprojects/asio/include/asio/basic_deadline_timer.hpp
new file mode 100644
index 000000000..5b20066df
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_deadline_timer.hpp
@@ -0,0 +1,628 @@
+//
+// basic_deadline_timer.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_DEADLINE_TIMER_HPP
+#define ASIO_BASIC_DEADLINE_TIMER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/time_traits.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/deadline_timer_service.hpp"
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/detail/deadline_timer_service.hpp"
+# define ASIO_SVC_T detail::deadline_timer_service<TimeTraits>
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides waitable timer functionality.
+/**
+ * The basic_deadline_timer class template provides the ability to perform a
+ * blocking or asynchronous wait for a timer to expire.
+ *
+ * A deadline timer is always in one of two states: "expired" or "not expired".
+ * If the wait() or async_wait() function is called on an expired timer, the
+ * wait operation will complete immediately.
+ *
+ * Most applications will use the asio::deadline_timer typedef.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Examples
+ * Performing a blocking wait:
+ * @code
+ * // Construct a timer without setting an expiry time.
+ * asio::deadline_timer timer(io_context);
+ *
+ * // Set an expiry time relative to now.
+ * timer.expires_from_now(boost::posix_time::seconds(5));
+ *
+ * // Wait for the timer to expire.
+ * timer.wait();
+ * @endcode
+ *
+ * @par 
+ * Performing an asynchronous wait:
+ * @code
+ * void handler(const asio::error_code& error)
+ * {
+ *   if (!error)
+ *   {
+ *     // Timer expired.
+ *   }
+ * }
+ *
+ * ...
+ *
+ * // Construct a timer with an absolute expiry time.
+ * asio::deadline_timer timer(io_context,
+ *     boost::posix_time::time_from_string("2005-12-07 23:59:59.000"));
+ *
+ * // Start an asynchronous wait.
+ * timer.async_wait(handler);
+ * @endcode
+ *
+ * @par Changing an active deadline_timer's expiry time
+ *
+ * Changing the expiry time of a timer while there are pending asynchronous
+ * waits causes those wait operations to be cancelled. To ensure that the action
+ * associated with the timer is performed only once, use something like this:
+ * used:
+ *
+ * @code
+ * void on_some_event()
+ * {
+ *   if (my_timer.expires_from_now(seconds(5)) > 0)
+ *   {
+ *     // We managed to cancel the timer. Start new asynchronous wait.
+ *     my_timer.async_wait(on_timeout);
+ *   }
+ *   else
+ *   {
+ *     // Too late, timer has already expired!
+ *   }
+ * }
+ *
+ * void on_timeout(const asio::error_code& e)
+ * {
+ *   if (e != asio::error::operation_aborted)
+ *   {
+ *     // Timer was not cancelled, take necessary action.
+ *   }
+ * }
+ * @endcode
+ *
+ * @li The asio::basic_deadline_timer::expires_from_now() function
+ * cancels any pending asynchronous waits, and returns the number of
+ * asynchronous waits that were cancelled. If it returns 0 then you were too
+ * late and the wait handler has already been executed, or will soon be
+ * executed. If it returns 1 then the wait handler was successfully cancelled.
+ *
+ * @li If a wait handler is cancelled, the asio::error_code passed to
+ * it contains the value asio::error::operation_aborted.
+ */
+template <typename Time,
+    typename TimeTraits = asio::time_traits<Time>
+    ASIO_SVC_TPARAM_DEF2(= deadline_timer_service<Time, TimeTraits>)>
+class basic_deadline_timer
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The time traits type.
+  typedef TimeTraits traits_type;
+
+  /// The time type.
+  typedef typename traits_type::time_type time_type;
+
+  /// The duration type.
+  typedef typename traits_type::duration_type duration_type;
+
+  /// Constructor.
+  /**
+   * This constructor creates a timer without setting an expiry time. The
+   * expires_at() or expires_from_now() functions must be called to set an
+   * expiry time before the timer can be waited on.
+   *
+   * @param io_context The io_context object that the timer will use to dispatch
+   * handlers for any asynchronous operations performed on the timer.
+   */
+  explicit basic_deadline_timer(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Constructor to set a particular expiry time as an absolute time.
+  /**
+   * This constructor creates a timer and sets the expiry time.
+   *
+   * @param io_context The io_context object that the timer will use to dispatch
+   * handlers for any asynchronous operations performed on the timer.
+   *
+   * @param expiry_time The expiry time to be used for the timer, expressed
+   * as an absolute time.
+   */
+  basic_deadline_timer(asio::io_context& io_context,
+      const time_type& expiry_time)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().expires_at(this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_at");
+  }
+
+  /// Constructor to set a particular expiry time relative to now.
+  /**
+   * This constructor creates a timer and sets the expiry time.
+   *
+   * @param io_context The io_context object that the timer will use to dispatch
+   * handlers for any asynchronous operations performed on the timer.
+   *
+   * @param expiry_time The expiry time to be used for the timer, relative to
+   * now.
+   */
+  basic_deadline_timer(asio::io_context& io_context,
+      const duration_type& expiry_time)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().expires_from_now(
+        this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_from_now");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_deadline_timer from another.
+  /**
+   * This constructor moves a timer from one object to another.
+   *
+   * @param other The other basic_deadline_timer object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_deadline_timer(io_context&) constructor.
+   */
+  basic_deadline_timer(basic_deadline_timer&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_deadline_timer from another.
+  /**
+   * This assignment operator moves a timer from one object to another. Cancels
+   * any outstanding asynchronous operations associated with the target object.
+   *
+   * @param other The other basic_deadline_timer object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_deadline_timer(io_context&) constructor.
+   */
+  basic_deadline_timer& operator=(basic_deadline_timer&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the timer.
+  /**
+   * This function destroys the timer, cancelling any outstanding asynchronous
+   * wait operations associated with the timer as if by calling @c cancel.
+   */
+  ~basic_deadline_timer()
+  {
+  }
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  // These functions are provided by basic_io_object<>.
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+  /// Cancel any asynchronous operations that are waiting on the timer.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the timer. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel()
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+    return s;
+  }
+
+  /// Cancel any asynchronous operations that are waiting on the timer.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the timer. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @note If the timer has already expired when cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel(asio::error_code& ec)
+  {
+    return this->get_service().cancel(this->get_implementation(), ec);
+  }
+
+  /// Cancels one asynchronous operation that is waiting on the timer.
+  /**
+   * This function forces the completion of one pending asynchronous wait
+   * operation against the timer. Handlers are cancelled in FIFO order. The
+   * handler for the cancelled operation will be invoked with the
+   * asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @return The number of asynchronous operations that were cancelled. That is,
+   * either 0 or 1.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when cancel_one() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel_one()
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().cancel_one(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel_one");
+    return s;
+  }
+
+  /// Cancels one asynchronous operation that is waiting on the timer.
+  /**
+   * This function forces the completion of one pending asynchronous wait
+   * operation against the timer. Handlers are cancelled in FIFO order. The
+   * handler for the cancelled operation will be invoked with the
+   * asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled. That is,
+   * either 0 or 1.
+   *
+   * @note If the timer has already expired when cancel_one() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel_one(asio::error_code& ec)
+  {
+    return this->get_service().cancel_one(this->get_implementation(), ec);
+  }
+
+  /// Get the timer's expiry time as an absolute time.
+  /**
+   * This function may be used to obtain the timer's current expiry time.
+   * Whether the timer has expired or not does not affect this value.
+   */
+  time_type expires_at() const
+  {
+    return this->get_service().expires_at(this->get_implementation());
+  }
+
+  /// Set the timer's expiry time as an absolute time.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when expires_at() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_at(const time_type& expiry_time)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().expires_at(
+        this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_at");
+    return s;
+  }
+
+  /// Set the timer's expiry time as an absolute time.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @note If the timer has already expired when expires_at() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_at(const time_type& expiry_time,
+      asio::error_code& ec)
+  {
+    return this->get_service().expires_at(
+        this->get_implementation(), expiry_time, ec);
+  }
+
+  /// Get the timer's expiry time relative to now.
+  /**
+   * This function may be used to obtain the timer's current expiry time.
+   * Whether the timer has expired or not does not affect this value.
+   */
+  duration_type expires_from_now() const
+  {
+    return this->get_service().expires_from_now(this->get_implementation());
+  }
+
+  /// Set the timer's expiry time relative to now.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when expires_from_now() is called,
+   * then the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_from_now(const duration_type& expiry_time)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().expires_from_now(
+        this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_from_now");
+    return s;
+  }
+
+  /// Set the timer's expiry time relative to now.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @note If the timer has already expired when expires_from_now() is called,
+   * then the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_from_now(const duration_type& expiry_time,
+      asio::error_code& ec)
+  {
+    return this->get_service().expires_from_now(
+        this->get_implementation(), expiry_time, ec);
+  }
+
+  /// Perform a blocking wait on the timer.
+  /**
+   * This function is used to wait for the timer to expire. This function
+   * blocks and does not return until the timer has expired.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void wait()
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Perform a blocking wait on the timer.
+  /**
+   * This function is used to wait for the timer to expire. This function
+   * blocks and does not return until the timer has expired.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  void wait(asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), ec);
+  }
+
+  /// Start an asynchronous wait on the timer.
+  /**
+   * This function may be used to initiate an asynchronous wait against the
+   * timer. It always returns immediately.
+   *
+   * For each call to async_wait(), the supplied handler will be called exactly
+   * once. The handler will be called when:
+   *
+   * @li The timer has expired.
+   *
+   * @li The timer was cancelled, in which case the handler is passed the error
+   * code asio::error::operation_aborted.
+   *
+   * @param handler The handler to be called when the timer expires. Copies
+   * will be made of the handler as required. The function signature of the
+   * handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WaitHandler.
+    ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_wait(this->get_implementation(),
+        ASIO_MOVE_CAST(WaitHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_wait(this->get_implementation(),
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# undef ASIO_SVC_T
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_BASIC_DEADLINE_TIMER_HPP
diff --git a/subprojects/asio/include/asio/basic_io_object.hpp b/subprojects/asio/include/asio/basic_io_object.hpp
new file mode 100644
index 000000000..442e85429
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_io_object.hpp
@@ -0,0 +1,290 @@
+//
+// basic_io_object.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_IO_OBJECT_HPP
+#define ASIO_BASIC_IO_OBJECT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if defined(ASIO_HAS_MOVE)
+namespace detail
+{
+  // Type trait used to determine whether a service supports move.
+  template <typename IoObjectService>
+  class service_has_move
+  {
+  private:
+    typedef IoObjectService service_type;
+    typedef typename service_type::implementation_type implementation_type;
+
+    template <typename T, typename U>
+    static auto asio_service_has_move_eval(T* t, U* u)
+      -> decltype(t->move_construct(*u, *u), char());
+    static char (&asio_service_has_move_eval(...))[2];
+
+  public:
+    static const bool value =
+      sizeof(asio_service_has_move_eval(
+        static_cast<service_type*>(0),
+        static_cast<implementation_type*>(0))) == 1;
+  };
+}
+#endif // defined(ASIO_HAS_MOVE)
+
+/// Base class for all I/O objects.
+/**
+ * @note All I/O objects are non-copyable. However, when using C++0x, certain
+ * I/O objects do support move construction and move assignment.
+ */
+#if !defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+template <typename IoObjectService>
+#else
+template <typename IoObjectService,
+    bool Movable = detail::service_has_move<IoObjectService>::value>
+#endif
+class basic_io_object
+{
+public:
+  /// The type of the service that will be used to provide I/O operations.
+  typedef IoObjectService service_type;
+
+  /// The underlying implementation type of I/O object.
+  typedef typename service_type::implementation_type implementation_type;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return service_.get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return service_.get_io_context();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// The type of the executor associated with the object.
+  typedef asio::io_context::executor_type executor_type;
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return service_.get_io_context().get_executor();
+  }
+
+protected:
+  /// Construct a basic_io_object.
+  /**
+   * Performs:
+   * @code get_service().construct(get_implementation()); @endcode
+   */
+  explicit basic_io_object(asio::io_context& io_context)
+    : service_(asio::use_service<IoObjectService>(io_context))
+  {
+    service_.construct(implementation_);
+  }
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_io_object.
+  /**
+   * Performs:
+   * @code get_service().move_construct(
+   *     get_implementation(), other.get_implementation()); @endcode
+   *
+   * @note Available only for services that support movability,
+   */
+  basic_io_object(basic_io_object&& other);
+
+  /// Move-assign a basic_io_object.
+  /**
+   * Performs:
+   * @code get_service().move_assign(get_implementation(),
+   *     other.get_service(), other.get_implementation()); @endcode
+   *
+   * @note Available only for services that support movability,
+   */
+  basic_io_object& operator=(basic_io_object&& other);
+
+  /// Perform a converting move-construction of a basic_io_object.
+  template <typename IoObjectService1>
+  basic_io_object(IoObjectService1& other_service,
+      typename IoObjectService1::implementation_type& other_implementation);
+#endif // defined(GENERATING_DOCUMENTATION)
+
+  /// Protected destructor to prevent deletion through this type.
+  /**
+   * Performs:
+   * @code get_service().destroy(get_implementation()); @endcode
+   */
+  ~basic_io_object()
+  {
+    service_.destroy(implementation_);
+  }
+
+  /// Get the service associated with the I/O object.
+  service_type& get_service()
+  {
+    return service_;
+  }
+
+  /// Get the service associated with the I/O object.
+  const service_type& get_service() const
+  {
+    return service_;
+  }
+
+  /// Get the underlying implementation of the I/O object.
+  implementation_type& get_implementation()
+  {
+    return implementation_;
+  }
+
+  /// Get the underlying implementation of the I/O object.
+  const implementation_type& get_implementation() const
+  {
+    return implementation_;
+  }
+
+private:
+  basic_io_object(const basic_io_object&);
+  basic_io_object& operator=(const basic_io_object&);
+
+  // The service associated with the I/O object.
+  service_type& service_;
+
+  /// The underlying implementation of the I/O object.
+  implementation_type implementation_;
+};
+
+#if defined(ASIO_HAS_MOVE)
+// Specialisation for movable objects.
+template <typename IoObjectService>
+class basic_io_object<IoObjectService, true>
+{
+public:
+  typedef IoObjectService service_type;
+  typedef typename service_type::implementation_type implementation_type;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  asio::io_context& get_io_context()
+  {
+    return service_->get_io_context();
+  }
+
+  asio::io_context& get_io_service()
+  {
+    return service_->get_io_context();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  typedef asio::io_context::executor_type executor_type;
+
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return service_->get_io_context().get_executor();
+  }
+
+protected:
+  explicit basic_io_object(asio::io_context& io_context)
+    : service_(&asio::use_service<IoObjectService>(io_context))
+  {
+    service_->construct(implementation_);
+  }
+
+  basic_io_object(basic_io_object&& other)
+    : service_(&other.get_service())
+  {
+    service_->move_construct(implementation_, other.implementation_);
+  }
+
+  template <typename IoObjectService1>
+  basic_io_object(IoObjectService1& other_service,
+      typename IoObjectService1::implementation_type& other_implementation)
+    : service_(&asio::use_service<IoObjectService>(
+          other_service.get_io_context()))
+  {
+    service_->converting_move_construct(implementation_,
+        other_service, other_implementation);
+  }
+
+  ~basic_io_object()
+  {
+    service_->destroy(implementation_);
+  }
+
+  basic_io_object& operator=(basic_io_object&& other)
+  {
+    service_->move_assign(implementation_,
+        *other.service_, other.implementation_);
+    service_ = other.service_;
+    return *this;
+  }
+
+  service_type& get_service()
+  {
+    return *service_;
+  }
+
+  const service_type& get_service() const
+  {
+    return *service_;
+  }
+
+  implementation_type& get_implementation()
+  {
+    return implementation_;
+  }
+
+  const implementation_type& get_implementation() const
+  {
+    return implementation_;
+  }
+
+private:
+  basic_io_object(const basic_io_object&);
+  void operator=(const basic_io_object&);
+
+  IoObjectService* service_;
+  implementation_type implementation_;
+};
+#endif // defined(ASIO_HAS_MOVE)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BASIC_IO_OBJECT_HPP
diff --git a/subprojects/asio/include/asio/basic_raw_socket.hpp b/subprojects/asio/include/asio/basic_raw_socket.hpp
new file mode 100644
index 000000000..0de7c7766
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_raw_socket.hpp
@@ -0,0 +1,1030 @@
+//
+// basic_raw_socket.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_RAW_SOCKET_HPP
+#define ASIO_BASIC_RAW_SOCKET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/basic_socket.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/raw_socket_service.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides raw-oriented socket functionality.
+/**
+ * The basic_raw_socket class template provides asynchronous and blocking
+ * raw-oriented socket functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= raw_socket_service<Protocol>)>
+class basic_raw_socket
+  : public basic_socket<Protocol ASIO_SVC_TARG>
+{
+public:
+  /// The native representation of a socket.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename basic_socket<
+    Protocol ASIO_SVC_TARG>::native_handle_type native_handle_type;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  /// Construct a basic_raw_socket without opening it.
+  /**
+   * This constructor creates a raw socket without opening it. The open()
+   * function must be called before data can be sent or received on the socket.
+   *
+   * @param io_context The io_context object that the raw socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   */
+  explicit basic_raw_socket(asio::io_context& io_context)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context)
+  {
+  }
+
+  /// Construct and open a basic_raw_socket.
+  /**
+   * This constructor creates and opens a raw socket.
+   *
+   * @param io_context The io_context object that the raw socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_raw_socket(asio::io_context& io_context,
+      const protocol_type& protocol)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, protocol)
+  {
+  }
+
+  /// Construct a basic_raw_socket, opening it and binding it to the given
+  /// local endpoint.
+  /**
+   * This constructor creates a raw socket and automatically opens it bound
+   * to the specified endpoint on the local machine. The protocol used is the
+   * protocol associated with the given endpoint.
+   *
+   * @param io_context The io_context object that the raw socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   *
+   * @param endpoint An endpoint on the local machine to which the raw
+   * socket will be bound.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_raw_socket(asio::io_context& io_context,
+      const endpoint_type& endpoint)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, endpoint)
+  {
+  }
+
+  /// Construct a basic_raw_socket on an existing native socket.
+  /**
+   * This constructor creates a raw socket object to hold an existing
+   * native socket.
+   *
+   * @param io_context The io_context object that the raw socket will use
+   * to dispatch handlers for any asynchronous operations performed on the
+   * socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @param native_socket The new underlying socket implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_raw_socket(asio::io_context& io_context,
+      const protocol_type& protocol, const native_handle_type& native_socket)
+    : basic_socket<Protocol ASIO_SVC_TARG>(
+        io_context, protocol, native_socket)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_raw_socket from another.
+  /**
+   * This constructor moves a raw socket from one object to another.
+   *
+   * @param other The other basic_raw_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_raw_socket(io_context&) constructor.
+   */
+  basic_raw_socket(basic_raw_socket&& other)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_raw_socket from another.
+  /**
+   * This assignment operator moves a raw socket from one object to another.
+   *
+   * @param other The other basic_raw_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_raw_socket(io_context&) constructor.
+   */
+  basic_raw_socket& operator=(basic_raw_socket&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+
+  /// Move-construct a basic_raw_socket from a socket of another protocol type.
+  /**
+   * This constructor moves a raw socket from one object to another.
+   *
+   * @param other The other basic_raw_socket object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_raw_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  basic_raw_socket(basic_raw_socket<Protocol1 ASIO_SVC_TARG1>&& other,
+      typename enable_if<is_convertible<Protocol1, Protocol>::value>::type* = 0)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_raw_socket from a socket of another protocol type.
+  /**
+   * This assignment operator moves a raw socket from one object to another.
+   *
+   * @param other The other basic_raw_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_raw_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  typename enable_if<is_convertible<Protocol1, Protocol>::value,
+      basic_raw_socket>::type& operator=(
+        basic_raw_socket<Protocol1 ASIO_SVC_TARG1>&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the socket.
+  /**
+   * This function destroys the socket, cancelling any outstanding asynchronous
+   * operations associated with the socket as if by calling @c cancel.
+   */
+  ~basic_raw_socket()
+  {
+  }
+
+  /// Send some data on a connected socket.
+  /**
+   * This function is used to send data on the raw socket. The function call
+   * will block until the data has been sent successfully or an error occurs.
+   *
+   * @param buffers One ore more data buffers to be sent on the socket.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The send operation can only be used with a connected socket. Use
+   * the send_to function to send data on an unconnected raw socket.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code socket.send(asio::buffer(data, size)); @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "send");
+    return s;
+  }
+
+  /// Send some data on a connected socket.
+  /**
+   * This function is used to send data on the raw socket. The function call
+   * will block until the data has been sent successfully or an error occurs.
+   *
+   * @param buffers One ore more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The send operation can only be used with a connected socket. Use
+   * the send_to function to send data on an unconnected raw socket.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+    asio::detail::throw_error(ec, "send");
+    return s;
+  }
+
+  /// Send some data on a connected socket.
+  /**
+   * This function is used to send data on the raw socket. The function call
+   * will block until the data has been sent successfully or an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @note The send operation can only be used with a connected socket. Use
+   * the send_to function to send data on an unconnected raw socket.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send on a connected socket.
+  /**
+   * This function is used to send data on the raw socket. The function call
+   * will block until the data has been sent successfully or an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * memory blocks is retained by the caller, which must guarantee that they
+   * remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_send operation can only be used with a connected socket.
+   * Use the async_send_to function to send data on an unconnected raw
+   * socket.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.async_send(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(this->get_implementation(),
+        buffers, 0, ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(this->get_implementation(),
+        buffers, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous send on a connected socket.
+  /**
+   * This function is used to send data on the raw socket. The function call
+   * will block until the data has been sent successfully or an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * memory blocks is retained by the caller, which must guarantee that they
+   * remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_send operation can only be used with a connected socket.
+   * Use the async_send_to function to send data on an unconnected raw
+   * socket.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(this->get_implementation(),
+        buffers, flags, ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(this->get_implementation(),
+        buffers, flags, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Send raw data to the specified endpoint.
+  /**
+   * This function is used to send raw data to the specified remote endpoint.
+   * The function call will block until the data has been sent successfully or
+   * an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * asio::ip::udp::endpoint destination(
+   *     asio::ip::address::from_string("1.2.3.4"), 12345);
+   * socket.send_to(asio::buffer(data, size), destination);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send_to(
+        this->get_implementation(), buffers, destination, 0, ec);
+    asio::detail::throw_error(ec, "send_to");
+    return s;
+  }
+
+  /// Send raw data to the specified endpoint.
+  /**
+   * This function is used to send raw data to the specified remote endpoint.
+   * The function call will block until the data has been sent successfully or
+   * an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send_to(
+        this->get_implementation(), buffers, destination, flags, ec);
+    asio::detail::throw_error(ec, "send_to");
+    return s;
+  }
+
+  /// Send raw data to the specified endpoint.
+  /**
+   * This function is used to send raw data to the specified remote endpoint.
+   * The function call will block until the data has been sent successfully or
+   * an error occurs.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes sent.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    return this->get_service().send_to(this->get_implementation(),
+        buffers, destination, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  /**
+   * This function is used to asynchronously send raw data to the specified
+   * remote endpoint. The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   * Copies will be made of the endpoint as required.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * asio::ip::udp::endpoint destination(
+   *     asio::ip::address::from_string("1.2.3.4"), 12345);
+   * socket.async_send_to(
+   *     asio::buffer(data, size), destination, handler);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send_to(this->get_implementation(),
+        buffers, destination, 0, ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send_to(this->get_implementation(),
+        buffers, destination, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous send.
+  /**
+   * This function is used to asynchronously send raw data to the specified
+   * remote endpoint. The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent to the remote endpoint.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param destination The remote endpoint to which the data will be sent.
+   * Copies will be made of the endpoint as required.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send_to(const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send_to(
+        this->get_implementation(), buffers, destination, flags,
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send_to(
+        this->get_implementation(), buffers, destination, flags,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the raw socket. The function
+   * call will block until data has been received successfully or an error
+   * occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The receive operation can only be used with a connected socket. Use
+   * the receive_from function to receive data on an unconnected raw
+   * socket.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code socket.receive(asio::buffer(data, size)); @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the raw socket. The function
+   * call will block until data has been received successfully or an error
+   * occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The receive operation can only be used with a connected socket. Use
+   * the receive_from function to receive data on an unconnected raw
+   * socket.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, flags, ec);
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the raw socket. The function
+   * call will block until data has been received successfully or an error
+   * occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes received.
+   *
+   * @note The receive operation can only be used with a connected socket. Use
+   * the receive_from function to receive data on an unconnected raw
+   * socket.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return this->get_service().receive(
+        this->get_implementation(), buffers, flags, ec);
+  }
+
+  /// Start an asynchronous receive on a connected socket.
+  /**
+   * This function is used to asynchronously receive data from the raw
+   * socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_receive operation can only be used with a connected socket.
+   * Use the async_receive_from function to receive data on an unconnected
+   * raw socket.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.async_receive(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous receive on a connected socket.
+  /**
+   * This function is used to asynchronously receive data from the raw
+   * socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The async_receive operation can only be used with a connected socket.
+   * Use the async_receive_from function to receive data on an unconnected
+   * raw socket.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(this->get_implementation(),
+        buffers, flags, ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive(this->get_implementation(),
+        buffers, flags, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Receive raw data with the endpoint of the sender.
+  /**
+   * This function is used to receive raw data. The function call will block
+   * until data has been received successfully or an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the data.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * asio::ip::udp::endpoint sender_endpoint;
+   * socket.receive_from(
+   *     asio::buffer(data, size), sender_endpoint);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive_from(
+        this->get_implementation(), buffers, sender_endpoint, 0, ec);
+    asio::detail::throw_error(ec, "receive_from");
+    return s;
+  }
+  
+  /// Receive raw data with the endpoint of the sender.
+  /**
+   * This function is used to receive raw data. The function call will block
+   * until data has been received successfully or an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the data.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive_from(
+        this->get_implementation(), buffers, sender_endpoint, flags, ec);
+    asio::detail::throw_error(ec, "receive_from");
+    return s;
+  }
+  
+  /// Receive raw data with the endpoint of the sender.
+  /**
+   * This function is used to receive raw data. The function call will block
+   * until data has been received successfully or an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the data.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes received.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    return this->get_service().receive_from(this->get_implementation(),
+        buffers, sender_endpoint, flags, ec);
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive raw data. The function
+   * call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the data. Ownership of the sender_endpoint object
+   * is retained by the caller, which must guarantee that it is valid until the
+   * handler is called.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code socket.async_receive_from(
+   *     asio::buffer(data, size), 0, sender_endpoint, handler); @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, 0,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, 0,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive raw data. The function
+   * call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param sender_endpoint An endpoint object that receives the endpoint of
+   * the remote sender of the data. Ownership of the sender_endpoint object
+   * is retained by the caller, which must guarantee that it is valid until the
+   * handler is called.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive_from(const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, flags,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive_from(
+        this->get_implementation(), buffers, sender_endpoint, flags,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BASIC_RAW_SOCKET_HPP
diff --git a/subprojects/asio/include/asio/basic_seq_packet_socket.hpp b/subprojects/asio/include/asio/basic_seq_packet_socket.hpp
new file mode 100644
index 000000000..3655d881c
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_seq_packet_socket.hpp
@@ -0,0 +1,618 @@
+//
+// basic_seq_packet_socket.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_SEQ_PACKET_SOCKET_HPP
+#define ASIO_BASIC_SEQ_PACKET_SOCKET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/basic_socket.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/seq_packet_socket_service.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides sequenced packet socket functionality.
+/**
+ * The basic_seq_packet_socket class template provides asynchronous and blocking
+ * sequenced packet socket functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= seq_packet_socket_service<Protocol>)>
+class basic_seq_packet_socket
+  : public basic_socket<Protocol ASIO_SVC_TARG>
+{
+public:
+  /// The native representation of a socket.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename basic_socket<
+    Protocol ASIO_SVC_TARG>::native_handle_type native_handle_type;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  /// Construct a basic_seq_packet_socket without opening it.
+  /**
+   * This constructor creates a sequenced packet socket without opening it. The
+   * socket needs to be opened and then connected or accepted before data can
+   * be sent or received on it.
+   *
+   * @param io_context The io_context object that the sequenced packet socket
+   * will use to dispatch handlers for any asynchronous operations performed on
+   * the socket.
+   */
+  explicit basic_seq_packet_socket(asio::io_context& io_context)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context)
+  {
+  }
+
+  /// Construct and open a basic_seq_packet_socket.
+  /**
+   * This constructor creates and opens a sequenced_packet socket. The socket
+   * needs to be connected or accepted before data can be sent or received on
+   * it.
+   *
+   * @param io_context The io_context object that the sequenced packet socket
+   * will use to dispatch handlers for any asynchronous operations performed on
+   * the socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_seq_packet_socket(asio::io_context& io_context,
+      const protocol_type& protocol)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, protocol)
+  {
+  }
+
+  /// Construct a basic_seq_packet_socket, opening it and binding it to the
+  /// given local endpoint.
+  /**
+   * This constructor creates a sequenced packet socket and automatically opens
+   * it bound to the specified endpoint on the local machine. The protocol used
+   * is the protocol associated with the given endpoint.
+   *
+   * @param io_context The io_context object that the sequenced packet socket
+   * will use to dispatch handlers for any asynchronous operations performed on
+   * the socket.
+   *
+   * @param endpoint An endpoint on the local machine to which the sequenced
+   * packet socket will be bound.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_seq_packet_socket(asio::io_context& io_context,
+      const endpoint_type& endpoint)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, endpoint)
+  {
+  }
+
+  /// Construct a basic_seq_packet_socket on an existing native socket.
+  /**
+   * This constructor creates a sequenced packet socket object to hold an
+   * existing native socket.
+   *
+   * @param io_context The io_context object that the sequenced packet socket
+   * will use to dispatch handlers for any asynchronous operations performed on
+   * the socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @param native_socket The new underlying socket implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_seq_packet_socket(asio::io_context& io_context,
+      const protocol_type& protocol, const native_handle_type& native_socket)
+    : basic_socket<Protocol ASIO_SVC_TARG>(
+        io_context, protocol, native_socket)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_seq_packet_socket from another.
+  /**
+   * This constructor moves a sequenced packet socket from one object to
+   * another.
+   *
+   * @param other The other basic_seq_packet_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_seq_packet_socket(io_context&) constructor.
+   */
+  basic_seq_packet_socket(basic_seq_packet_socket&& other)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_seq_packet_socket from another.
+  /**
+   * This assignment operator moves a sequenced packet socket from one object to
+   * another.
+   *
+   * @param other The other basic_seq_packet_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_seq_packet_socket(io_context&) constructor.
+   */
+  basic_seq_packet_socket& operator=(basic_seq_packet_socket&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+
+  /// Move-construct a basic_seq_packet_socket from a socket of another protocol
+  /// type.
+  /**
+   * This constructor moves a sequenced packet socket from one object to
+   * another.
+   *
+   * @param other The other basic_seq_packet_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_seq_packet_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  basic_seq_packet_socket(
+      basic_seq_packet_socket<Protocol1 ASIO_SVC_TARG1>&& other,
+      typename enable_if<is_convertible<Protocol1, Protocol>::value>::type* = 0)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_seq_packet_socket from a socket of another protocol
+  /// type.
+  /**
+   * This assignment operator moves a sequenced packet socket from one object to
+   * another.
+   *
+   * @param other The other basic_seq_packet_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_seq_packet_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  typename enable_if<is_convertible<Protocol1, Protocol>::value,
+      basic_seq_packet_socket>::type& operator=(
+        basic_seq_packet_socket<Protocol1 ASIO_SVC_TARG1>&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the socket.
+  /**
+   * This function destroys the socket, cancelling any outstanding asynchronous
+   * operations associated with the socket as if by calling @c cancel.
+   */
+  ~basic_seq_packet_socket()
+  {
+  }
+
+  /// Send some data on the socket.
+  /**
+   * This function is used to send data on the sequenced packet socket. The
+   * function call will block until the data has been sent successfully, or an
+   * until error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.send(asio::buffer(data, size), 0);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+    asio::detail::throw_error(ec, "send");
+    return s;
+  }
+
+  /// Send some data on the socket.
+  /**
+   * This function is used to send data on the sequenced packet socket. The
+   * function call will block the data has been sent successfully, or an until
+   * error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes sent. Returns 0 if an error occurred.
+   *
+   * @note The send operation may not transmit all of the data to the peer.
+   * Consider using the @ref write function if you need to ensure that all data
+   * is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  /**
+   * This function is used to asynchronously send data on the sequenced packet
+   * socket. The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent on the socket. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * memory blocks is retained by the caller, which must guarantee that they
+   * remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.async_send(asio::buffer(data, size), 0, handler);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(this->get_implementation(),
+        buffers, flags, ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(this->get_implementation(),
+        buffers, flags, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Receive some data on the socket.
+  /**
+   * This function is used to receive data on the sequenced packet socket. The
+   * function call will block until data has been received successfully, or
+   * until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param out_flags After the receive call completes, contains flags
+   * associated with the received data. For example, if the
+   * socket_base::message_end_of_record bit is set then the received data marks
+   * the end of a record.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.receive(asio::buffer(data, size), out_flags);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags& out_flags)
+  {
+    asio::error_code ec;
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, 0, out_flags, ec);
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    std::size_t s = this->get_service().receive_with_flags(
+        this->get_implementation(), buffers, 0, out_flags, ec);
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on the socket.
+  /**
+   * This function is used to receive data on the sequenced packet socket. The
+   * function call will block until data has been received successfully, or
+   * until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param in_flags Flags specifying how the receive call is to be made.
+   *
+   * @param out_flags After the receive call completes, contains flags
+   * associated with the received data. For example, if the
+   * socket_base::message_end_of_record bit is set then the received data marks
+   * the end of a record.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The receive operation may not receive all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that the
+   * requested amount of data is read before the blocking operation completes.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.receive(asio::buffer(data, size), 0, out_flags);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags)
+  {
+    asio::error_code ec;
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, in_flags, out_flags, ec);
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    std::size_t s = this->get_service().receive_with_flags(
+        this->get_implementation(), buffers, in_flags, out_flags, ec);
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the sequenced packet socket. The
+   * function call will block until data has been received successfully, or
+   * until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param in_flags Flags specifying how the receive call is to be made.
+   *
+   * @param out_flags After the receive call completes, contains flags
+   * associated with the received data. For example, if the
+   * socket_base::message_end_of_record bit is set then the received data marks
+   * the end of a record.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes received. Returns 0 if an error occurred.
+   *
+   * @note The receive operation may not receive all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that the
+   * requested amount of data is read before the blocking operation completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, asio::error_code& ec)
+  {
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().receive(this->get_implementation(),
+        buffers, in_flags, out_flags, ec);
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().receive_with_flags(this->get_implementation(),
+        buffers, in_flags, out_flags, ec);
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive data from the sequenced
+   * packet socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param out_flags Once the asynchronous operation completes, contains flags
+   * associated with the received data. For example, if the
+   * socket_base::message_end_of_record bit is set then the received data marks
+   * the end of a record. The caller must guarantee that the referenced
+   * variable remains valid until the handler is called.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.async_receive(asio::buffer(data, size), out_flags, handler);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags& out_flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(
+        this->get_implementation(), buffers, 0, out_flags,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive_with_flags(
+        this->get_implementation(), buffers, 0, out_flags,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive data from the sequenced
+   * data socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param in_flags Flags specifying how the receive call is to be made.
+   *
+   * @param out_flags Once the asynchronous operation completes, contains flags
+   * associated with the received data. For example, if the
+   * socket_base::message_end_of_record bit is set then the received data marks
+   * the end of a record. The caller must guarantee that the referenced
+   * variable remains valid until the handler is called.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.async_receive(
+   *     asio::buffer(data, size),
+   *     0, out_flags, handler);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(
+        this->get_implementation(), buffers, in_flags, out_flags,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive_with_flags(
+        this->get_implementation(), buffers, in_flags, out_flags,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BASIC_SEQ_PACKET_SOCKET_HPP
diff --git a/subprojects/asio/include/asio/basic_serial_port.hpp b/subprojects/asio/include/asio/basic_serial_port.hpp
new file mode 100644
index 000000000..32262f842
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_serial_port.hpp
@@ -0,0 +1,688 @@
+//
+// basic_serial_port.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_SERIAL_PORT_HPP
+#define ASIO_BASIC_SERIAL_PORT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_SERIAL_PORT) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <string>
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/serial_port_base.hpp"
+#include "asio/serial_port_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides serial port functionality.
+/**
+ * The basic_serial_port class template provides functionality that is common
+ * to all serial ports.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename SerialPortService = serial_port_service>
+class basic_serial_port
+  : public basic_io_object<SerialPortService>,
+    public serial_port_base
+{
+public:
+  /// The native representation of a serial port.
+  typedef typename SerialPortService::native_handle_type native_handle_type;
+
+  /// A basic_serial_port is always the lowest layer.
+  typedef basic_serial_port<SerialPortService> lowest_layer_type;
+
+  /// Construct a basic_serial_port without opening it.
+  /**
+   * This constructor creates a serial port without opening it.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   */
+  explicit basic_serial_port(asio::io_context& io_context)
+    : basic_io_object<SerialPortService>(io_context)
+  {
+  }
+
+  /// Construct and open a basic_serial_port.
+  /**
+   * This constructor creates and opens a serial port for the specified device
+   * name.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   *
+   * @param device The platform-specific device name for this serial
+   * port.
+   */
+  explicit basic_serial_port(asio::io_context& io_context,
+      const char* device)
+    : basic_io_object<SerialPortService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), device, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Construct and open a basic_serial_port.
+  /**
+   * This constructor creates and opens a serial port for the specified device
+   * name.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   *
+   * @param device The platform-specific device name for this serial
+   * port.
+   */
+  explicit basic_serial_port(asio::io_context& io_context,
+      const std::string& device)
+    : basic_io_object<SerialPortService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), device, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Construct a basic_serial_port on an existing native serial port.
+  /**
+   * This constructor creates a serial port object to hold an existing native
+   * serial port.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   *
+   * @param native_serial_port A native serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_serial_port(asio::io_context& io_context,
+      const native_handle_type& native_serial_port)
+    : basic_io_object<SerialPortService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_serial_port, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_serial_port from another.
+  /**
+   * This constructor moves a serial port from one object to another.
+   *
+   * @param other The other basic_serial_port object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_serial_port(io_context&) constructor.
+   */
+  basic_serial_port(basic_serial_port&& other)
+    : basic_io_object<SerialPortService>(
+        ASIO_MOVE_CAST(basic_serial_port)(other))
+  {
+  }
+
+  /// Move-assign a basic_serial_port from another.
+  /**
+   * This assignment operator moves a serial port from one object to another.
+   *
+   * @param other The other basic_serial_port object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_serial_port(io_context&) constructor.
+   */
+  basic_serial_port& operator=(basic_serial_port&& other)
+  {
+    basic_io_object<SerialPortService>::operator=(
+        ASIO_MOVE_CAST(basic_serial_port)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since a basic_serial_port cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since a basic_serial_port cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+
+  /// Open the serial port using the specified device name.
+  /**
+   * This function opens the serial port for the specified device name.
+   *
+   * @param device The platform-specific device name.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void open(const std::string& device)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), device, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Open the serial port using the specified device name.
+  /**
+   * This function opens the serial port using the given platform-specific
+   * device name.
+   *
+   * @param device The platform-specific device name.
+   *
+   * @param ec Set the indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID open(const std::string& device,
+      asio::error_code& ec)
+  {
+    this->get_service().open(this->get_implementation(), device, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native serial port to the serial port.
+  /*
+   * This function opens the serial port to hold an existing native serial port.
+   *
+   * @param native_serial_port A native serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const native_handle_type& native_serial_port)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_serial_port, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native serial port to the serial port.
+  /*
+   * This function opens the serial port to hold an existing native serial port.
+   *
+   * @param native_serial_port A native serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const native_handle_type& native_serial_port,
+      asio::error_code& ec)
+  {
+    this->get_service().assign(this->get_implementation(),
+        native_serial_port, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the serial port is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the serial port.
+  /**
+   * This function is used to close the serial port. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the serial port.
+  /**
+   * This function is used to close the serial port. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native serial port representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * serial port. This is intended to allow access to native serial port
+   * functionality that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the serial port.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the serial port.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Send a break sequence to the serial port.
+  /**
+   * This function causes a break sequence of platform-specific duration to be
+   * sent out the serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void send_break()
+  {
+    asio::error_code ec;
+    this->get_service().send_break(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "send_break");
+  }
+
+  /// Send a break sequence to the serial port.
+  /**
+   * This function causes a break sequence of platform-specific duration to be
+   * sent out the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID send_break(asio::error_code& ec)
+  {
+    this->get_service().send_break(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Set an option on the serial port.
+  /**
+   * This function is used to set an option on the serial port.
+   *
+   * @param option The option value to be set on the serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa SettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename SettableSerialPortOption>
+  void set_option(const SettableSerialPortOption& option)
+  {
+    asio::error_code ec;
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "set_option");
+  }
+
+  /// Set an option on the serial port.
+  /**
+   * This function is used to set an option on the serial port.
+   *
+   * @param option The option value to be set on the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa SettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename SettableSerialPortOption>
+  ASIO_SYNC_OP_VOID set_option(const SettableSerialPortOption& option,
+      asio::error_code& ec)
+  {
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get an option from the serial port.
+  /**
+   * This function is used to get the current value of an option on the serial
+   * port.
+   *
+   * @param option The option value to be obtained from the serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa GettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename GettableSerialPortOption>
+  void get_option(GettableSerialPortOption& option)
+  {
+    asio::error_code ec;
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "get_option");
+  }
+
+  /// Get an option from the serial port.
+  /**
+   * This function is used to get the current value of an option on the serial
+   * port.
+   *
+   * @param option The option value to be obtained from the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa GettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename GettableSerialPortOption>
+  ASIO_SYNC_OP_VOID get_option(GettableSerialPortOption& option,
+      asio::error_code& ec)
+  {
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Write some data to the serial port.
+  /**
+   * This function is used to write data to the serial port. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the serial port.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.write_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return s;
+  }
+
+  /// Write some data to the serial port.
+  /**
+   * This function is used to write data to the serial port. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write data to the serial port.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be written to the serial port.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.async_write_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    return this->get_service().async_write_some(this->get_implementation(),
+        buffers, ASIO_MOVE_CAST(WriteHandler)(handler));
+  }
+
+  /// Read some data from the serial port.
+  /**
+   * This function is used to read data from the serial port. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.read_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return s;
+  }
+
+  /// Read some data from the serial port.
+  /**
+   * This function is used to read data from the serial port. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read data from the serial port.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read function if you need to ensure that the
+   * requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.async_read_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    return this->get_service().async_read_some(this->get_implementation(),
+        buffers, ASIO_MOVE_CAST(ReadHandler)(handler));
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_SERIAL_PORT)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_BASIC_SERIAL_PORT_HPP
diff --git a/subprojects/asio/include/asio/basic_signal_set.hpp b/subprojects/asio/include/asio/basic_signal_set.hpp
new file mode 100644
index 000000000..cf34643f8
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_signal_set.hpp
@@ -0,0 +1,391 @@
+//
+// basic_signal_set.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_SIGNAL_SET_HPP
+#define ASIO_BASIC_SIGNAL_SET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/signal_set_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides signal functionality.
+/**
+ * The basic_signal_set class template provides the ability to perform an
+ * asynchronous wait for one or more signals to occur.
+ *
+ * Most applications will use the asio::signal_set typedef.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Example
+ * Performing an asynchronous wait:
+ * @code
+ * void handler(
+ *     const asio::error_code& error,
+ *     int signal_number)
+ * {
+ *   if (!error)
+ *   {
+ *     // A signal occurred.
+ *   }
+ * }
+ *
+ * ...
+ *
+ * // Construct a signal set registered for process termination.
+ * asio::signal_set signals(io_context, SIGINT, SIGTERM);
+ *
+ * // Start an asynchronous wait for one of the signals to occur.
+ * signals.async_wait(handler);
+ * @endcode
+ *
+ * @par Queueing of signal notifications
+ *
+ * If a signal is registered with a signal_set, and the signal occurs when
+ * there are no waiting handlers, then the signal notification is queued. The
+ * next async_wait operation on that signal_set will dequeue the notification.
+ * If multiple notifications are queued, subsequent async_wait operations
+ * dequeue them one at a time. Signal notifications are dequeued in order of
+ * ascending signal number.
+ *
+ * If a signal number is removed from a signal_set (using the @c remove or @c
+ * erase member functions) then any queued notifications for that signal are
+ * discarded.
+ *
+ * @par Multiple registration of signals
+ *
+ * The same signal number may be registered with different signal_set objects.
+ * When the signal occurs, one handler is called for each signal_set object.
+ *
+ * Note that multiple registration only works for signals that are registered
+ * using Asio. The application must not also register a signal handler using
+ * functions such as @c signal() or @c sigaction().
+ *
+ * @par Signal masking on POSIX platforms
+ *
+ * POSIX allows signals to be blocked using functions such as @c sigprocmask()
+ * and @c pthread_sigmask(). For signals to be delivered, programs must ensure
+ * that any signals registered using signal_set objects are unblocked in at
+ * least one thread.
+ */
+template <typename SignalSetService = signal_set_service>
+class basic_signal_set
+  : public basic_io_object<SignalSetService>
+{
+public:
+  /// Construct a signal set without adding any signals.
+  /**
+   * This constructor creates a signal set without registering for any signals.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   */
+  explicit basic_signal_set(asio::io_context& io_context)
+    : basic_io_object<SignalSetService>(io_context)
+  {
+  }
+
+  /// Construct a signal set and add one signal.
+  /**
+   * This constructor creates a signal set and registers for one signal.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   *
+   * @param signal_number_1 The signal number to be added.
+   *
+   * @note This constructor is equivalent to performing:
+   * @code asio::signal_set signals(io_context);
+   * signals.add(signal_number_1); @endcode
+   */
+  basic_signal_set(asio::io_context& io_context, int signal_number_1)
+    : basic_io_object<SignalSetService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number_1, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Construct a signal set and add two signals.
+  /**
+   * This constructor creates a signal set and registers for two signals.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   *
+   * @param signal_number_1 The first signal number to be added.
+   *
+   * @param signal_number_2 The second signal number to be added.
+   *
+   * @note This constructor is equivalent to performing:
+   * @code asio::signal_set signals(io_context);
+   * signals.add(signal_number_1);
+   * signals.add(signal_number_2); @endcode
+   */
+  basic_signal_set(asio::io_context& io_context, int signal_number_1,
+      int signal_number_2)
+    : basic_io_object<SignalSetService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number_1, ec);
+    asio::detail::throw_error(ec, "add");
+    this->get_service().add(this->get_implementation(), signal_number_2, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Construct a signal set and add three signals.
+  /**
+   * This constructor creates a signal set and registers for three signals.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   *
+   * @param signal_number_1 The first signal number to be added.
+   *
+   * @param signal_number_2 The second signal number to be added.
+   *
+   * @param signal_number_3 The third signal number to be added.
+   *
+   * @note This constructor is equivalent to performing:
+   * @code asio::signal_set signals(io_context);
+   * signals.add(signal_number_1);
+   * signals.add(signal_number_2);
+   * signals.add(signal_number_3); @endcode
+   */
+  basic_signal_set(asio::io_context& io_context, int signal_number_1,
+      int signal_number_2, int signal_number_3)
+    : basic_io_object<SignalSetService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number_1, ec);
+    asio::detail::throw_error(ec, "add");
+    this->get_service().add(this->get_implementation(), signal_number_2, ec);
+    asio::detail::throw_error(ec, "add");
+    this->get_service().add(this->get_implementation(), signal_number_3, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Add a signal to a signal_set.
+  /**
+   * This function adds the specified signal to the set. It has no effect if the
+   * signal is already in the set.
+   *
+   * @param signal_number The signal to be added to the set.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void add(int signal_number)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Add a signal to a signal_set.
+  /**
+   * This function adds the specified signal to the set. It has no effect if the
+   * signal is already in the set.
+   *
+   * @param signal_number The signal to be added to the set.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID add(int signal_number, asio::error_code& ec)
+  {
+    this->get_service().add(this->get_implementation(), signal_number, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Remove a signal from a signal_set.
+  /**
+   * This function removes the specified signal from the set. It has no effect
+   * if the signal is not in the set.
+   *
+   * @param signal_number The signal to be removed from the set.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Removes any notifications that have been queued for the specified
+   * signal number.
+   */
+  void remove(int signal_number)
+  {
+    asio::error_code ec;
+    this->get_service().remove(this->get_implementation(), signal_number, ec);
+    asio::detail::throw_error(ec, "remove");
+  }
+
+  /// Remove a signal from a signal_set.
+  /**
+   * This function removes the specified signal from the set. It has no effect
+   * if the signal is not in the set.
+   *
+   * @param signal_number The signal to be removed from the set.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Removes any notifications that have been queued for the specified
+   * signal number.
+   */
+  ASIO_SYNC_OP_VOID remove(int signal_number,
+      asio::error_code& ec)
+  {
+    this->get_service().remove(this->get_implementation(), signal_number, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Remove all signals from a signal_set.
+  /**
+   * This function removes all signals from the set. It has no effect if the set
+   * is already empty.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Removes all queued notifications.
+   */
+  void clear()
+  {
+    asio::error_code ec;
+    this->get_service().clear(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "clear");
+  }
+
+  /// Remove all signals from a signal_set.
+  /**
+   * This function removes all signals from the set. It has no effect if the set
+   * is already empty.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Removes all queued notifications.
+   */
+  ASIO_SYNC_OP_VOID clear(asio::error_code& ec)
+  {
+    this->get_service().clear(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Cancel all operations associated with the signal set.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the signal set. The handler for each cancelled
+   * operation will be invoked with the asio::error::operation_aborted
+   * error code.
+   *
+   * Cancellation does not alter the set of registered signals.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If a registered signal occurred before cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all operations associated with the signal set.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the signal set. The handler for each cancelled
+   * operation will be invoked with the asio::error::operation_aborted
+   * error code.
+   *
+   * Cancellation does not alter the set of registered signals.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note If a registered signal occurred before cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous operation to wait for a signal to be delivered.
+  /**
+   * This function may be used to initiate an asynchronous wait against the
+   * signal set. It always returns immediately.
+   *
+   * For each call to async_wait(), the supplied handler will be called exactly
+   * once. The handler will be called when:
+   *
+   * @li One of the registered signals in the signal set occurs; or
+   *
+   * @li The signal set was cancelled, in which case the handler is passed the
+   * error code asio::error::operation_aborted.
+   *
+   * @param handler The handler to be called when the signal occurs. Copies
+   * will be made of the handler as required. The function signature of the
+   * handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   int signal_number // Indicates which signal occurred.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename SignalHandler>
+  ASIO_INITFN_RESULT_TYPE(SignalHandler,
+      void (asio::error_code, int))
+  async_wait(ASIO_MOVE_ARG(SignalHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a SignalHandler.
+    ASIO_SIGNAL_HANDLER_CHECK(SignalHandler, handler) type_check;
+
+    return this->get_service().async_wait(this->get_implementation(),
+        ASIO_MOVE_CAST(SignalHandler)(handler));
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_BASIC_SIGNAL_SET_HPP
diff --git a/subprojects/asio/include/asio/basic_socket.hpp b/subprojects/asio/include/asio/basic_socket.hpp
new file mode 100644
index 000000000..3dfacb424
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_socket.hpp
@@ -0,0 +1,1757 @@
+//
+// basic_socket.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_SOCKET_HPP
+#define ASIO_BASIC_SOCKET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/async_result.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/post.hpp"
+#include "asio/socket_base.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# if defined(ASIO_WINDOWS_RUNTIME)
+#  include "asio/detail/winrt_ssocket_service.hpp"
+#  define ASIO_SVC_T detail::winrt_ssocket_service<Protocol>
+# elif defined(ASIO_HAS_IOCP)
+#  include "asio/detail/win_iocp_socket_service.hpp"
+#  define ASIO_SVC_T detail::win_iocp_socket_service<Protocol>
+# else
+#  include "asio/detail/reactive_socket_service.hpp"
+#  define ASIO_SVC_T detail::reactive_socket_service<Protocol>
+# endif
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides socket functionality.
+/**
+ * The basic_socket class template provides functionality that is common to both
+ * stream-oriented and datagram-oriented sockets.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename Protocol ASIO_SVC_TPARAM>
+class basic_socket
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>,
+    public socket_base
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The native representation of a socket.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename ASIO_SVC_T::native_handle_type native_handle_type;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+#if !defined(ASIO_NO_EXTENSIONS)
+  /// A basic_socket is always the lowest layer.
+  typedef basic_socket<Protocol ASIO_SVC_TARG> lowest_layer_type;
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+  /// Construct a basic_socket without opening it.
+  /**
+   * This constructor creates a socket without opening it.
+   *
+   * @param io_context The io_context object that the socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   */
+  explicit basic_socket(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Construct and open a basic_socket.
+  /**
+   * This constructor creates and opens a socket.
+   *
+   * @param io_context The io_context object that the socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_socket(asio::io_context& io_context,
+      const protocol_type& protocol)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Construct a basic_socket, opening it and binding it to the given local
+  /// endpoint.
+  /**
+   * This constructor creates a socket and automatically opens it bound to the
+   * specified endpoint on the local machine. The protocol used is the protocol
+   * associated with the given endpoint.
+   *
+   * @param io_context The io_context object that the socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   *
+   * @param endpoint An endpoint on the local machine to which the socket will
+   * be bound.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_socket(asio::io_context& io_context,
+      const endpoint_type& endpoint)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    const protocol_type protocol = endpoint.protocol();
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    asio::detail::throw_error(ec, "open");
+    this->get_service().bind(this->get_implementation(), endpoint, ec);
+    asio::detail::throw_error(ec, "bind");
+  }
+
+  /// Construct a basic_socket on an existing native socket.
+  /**
+   * This constructor creates a socket object to hold an existing native socket.
+   *
+   * @param io_context The io_context object that the socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @param native_socket A native socket.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_socket(asio::io_context& io_context,
+      const protocol_type& protocol, const native_handle_type& native_socket)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        protocol, native_socket, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_socket from another.
+  /**
+   * This constructor moves a socket from one object to another.
+   *
+   * @param other The other basic_socket object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket(io_context&) constructor.
+   */
+  basic_socket(basic_socket&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_socket from another.
+  /**
+   * This assignment operator moves a socket from one object to another.
+   *
+   * @param other The other basic_socket object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket(io_context&) constructor.
+   */
+  basic_socket& operator=(basic_socket&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+
+  // All sockets have access to each other's implementations.
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  friend class basic_socket;
+
+  /// Move-construct a basic_socket from a socket of another protocol type.
+  /**
+   * This constructor moves a socket from one object to another.
+   *
+   * @param other The other basic_socket object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  basic_socket(basic_socket<Protocol1 ASIO_SVC_TARG1>&& other,
+      typename enable_if<is_convertible<Protocol1, Protocol>::value>::type* = 0)
+    : basic_io_object<ASIO_SVC_T>(
+        other.get_service(), other.get_implementation())
+  {
+  }
+
+  /// Move-assign a basic_socket from a socket of another protocol type.
+  /**
+   * This assignment operator moves a socket from one object to another.
+   *
+   * @param other The other basic_socket object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  typename enable_if<is_convertible<Protocol1, Protocol>::value,
+      basic_socket>::type& operator=(
+        basic_socket<Protocol1 ASIO_SVC_TARG1>&& other)
+  {
+    basic_socket tmp(std::move(other));
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(tmp));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  // These functions are provided by basic_io_object<>.
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if !defined(ASIO_NO_EXTENSIONS)
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since a basic_socket cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since a basic_socket cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+  /// Open the socket using the specified protocol.
+  /**
+   * This function opens the socket so that it will use the specified protocol.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * socket.open(asio::ip::tcp::v4());
+   * @endcode
+   */
+  void open(const protocol_type& protocol = protocol_type())
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Open the socket using the specified protocol.
+  /**
+   * This function opens the socket so that it will use the specified protocol.
+   *
+   * @param protocol An object specifying which protocol is to be used.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * asio::error_code ec;
+   * socket.open(asio::ip::tcp::v4(), ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID open(const protocol_type& protocol,
+      asio::error_code& ec)
+  {
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native socket to the socket.
+  /*
+   * This function opens the socket to hold an existing native socket.
+   *
+   * @param protocol An object specifying which protocol is to be used.
+   *
+   * @param native_socket A native socket.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const protocol_type& protocol,
+      const native_handle_type& native_socket)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        protocol, native_socket, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native socket to the socket.
+  /*
+   * This function opens the socket to hold an existing native socket.
+   *
+   * @param protocol An object specifying which protocol is to be used.
+   *
+   * @param native_socket A native socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const protocol_type& protocol,
+      const native_handle_type& native_socket, asio::error_code& ec)
+  {
+    this->get_service().assign(this->get_implementation(),
+        protocol, native_socket, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the socket.
+  /**
+   * This function is used to close the socket. Any asynchronous send, receive
+   * or connect operations will be cancelled immediately, and will complete
+   * with the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure. Note that, even if
+   * the function indicates an error, the underlying descriptor is closed.
+   *
+   * @note For portable behaviour with respect to graceful closure of a
+   * connected socket, call shutdown() before closing the socket.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the socket.
+  /**
+   * This function is used to close the socket. Any asynchronous send, receive
+   * or connect operations will be cancelled immediately, and will complete
+   * with the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any. Note that, even if
+   * the function indicates an error, the underlying descriptor is closed.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::error_code ec;
+   * socket.close(ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   *
+   * @note For portable behaviour with respect to graceful closure of a
+   * connected socket, call shutdown() before closing the socket.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Release ownership of the underlying native socket.
+  /**
+   * This function causes all outstanding asynchronous connect, send and receive
+   * operations to finish immediately, and the handlers for cancelled operations
+   * will be passed the asio::error::operation_aborted error. Ownership
+   * of the native socket is then transferred to the caller.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note This function is unsupported on Windows versions prior to Windows
+   * 8.1, and will fail with asio::error::operation_not_supported on
+   * these platforms.
+   */
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1400) \
+  && (!defined(_WIN32_WINNT) || _WIN32_WINNT < 0x0603)
+  __declspec(deprecated("This function always fails with "
+        "operation_not_supported when used on Windows versions "
+        "prior to Windows 8.1."))
+#endif
+  native_handle_type release()
+  {
+    asio::error_code ec;
+    native_handle_type s = this->get_service().release(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "release");
+    return s;
+  }
+
+  /// Release ownership of the underlying native socket.
+  /**
+   * This function causes all outstanding asynchronous connect, send and receive
+   * operations to finish immediately, and the handlers for cancelled operations
+   * will be passed the asio::error::operation_aborted error. Ownership
+   * of the native socket is then transferred to the caller.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note This function is unsupported on Windows versions prior to Windows
+   * 8.1, and will fail with asio::error::operation_not_supported on
+   * these platforms.
+   */
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1400) \
+  && (!defined(_WIN32_WINNT) || _WIN32_WINNT < 0x0603)
+  __declspec(deprecated("This function always fails with "
+        "operation_not_supported when used on Windows versions "
+        "prior to Windows 8.1."))
+#endif
+  native_handle_type release(asio::error_code& ec)
+  {
+    return this->get_service().release(this->get_implementation(), ec);
+  }
+
+  /// Get the native socket representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * socket. This is intended to allow access to native socket functionality
+   * that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the socket.
+  /**
+   * This function causes all outstanding asynchronous connect, send and receive
+   * operations to finish immediately, and the handlers for cancelled operations
+   * will be passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls to cancel() will always fail with
+   * asio::error::operation_not_supported when run on Windows XP, Windows
+   * Server 2003, and earlier versions of Windows, unless
+   * ASIO_ENABLE_CANCELIO is defined. However, the CancelIo function has
+   * two issues that should be considered before enabling its use:
+   *
+   * @li It will only cancel asynchronous operations that were initiated in the
+   * current thread.
+   *
+   * @li It can appear to complete without error, but the request to cancel the
+   * unfinished operations may be silently ignored by the operating system.
+   * Whether it works or not seems to depend on the drivers that are installed.
+   *
+   * For portable cancellation, consider using one of the following
+   * alternatives:
+   *
+   * @li Disable asio's I/O completion port backend by defining
+   * ASIO_DISABLE_IOCP.
+   *
+   * @li Use the close() function to simultaneously cancel the outstanding
+   * operations and close the socket.
+   *
+   * When running on Windows Vista, Windows Server 2008, and later, the
+   * CancelIoEx function is always used. This function does not have the
+   * problems described above.
+   */
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1400) \
+  && (!defined(_WIN32_WINNT) || _WIN32_WINNT < 0x0600) \
+  && !defined(ASIO_ENABLE_CANCELIO)
+  __declspec(deprecated("By default, this function always fails with "
+        "operation_not_supported when used on Windows XP, Windows Server 2003, "
+        "or earlier. Consult documentation for details."))
+#endif
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the socket.
+  /**
+   * This function causes all outstanding asynchronous connect, send and receive
+   * operations to finish immediately, and the handlers for cancelled operations
+   * will be passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls to cancel() will always fail with
+   * asio::error::operation_not_supported when run on Windows XP, Windows
+   * Server 2003, and earlier versions of Windows, unless
+   * ASIO_ENABLE_CANCELIO is defined. However, the CancelIo function has
+   * two issues that should be considered before enabling its use:
+   *
+   * @li It will only cancel asynchronous operations that were initiated in the
+   * current thread.
+   *
+   * @li It can appear to complete without error, but the request to cancel the
+   * unfinished operations may be silently ignored by the operating system.
+   * Whether it works or not seems to depend on the drivers that are installed.
+   *
+   * For portable cancellation, consider using one of the following
+   * alternatives:
+   *
+   * @li Disable asio's I/O completion port backend by defining
+   * ASIO_DISABLE_IOCP.
+   *
+   * @li Use the close() function to simultaneously cancel the outstanding
+   * operations and close the socket.
+   *
+   * When running on Windows Vista, Windows Server 2008, and later, the
+   * CancelIoEx function is always used. This function does not have the
+   * problems described above.
+   */
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1400) \
+  && (!defined(_WIN32_WINNT) || _WIN32_WINNT < 0x0600) \
+  && !defined(ASIO_ENABLE_CANCELIO)
+  __declspec(deprecated("By default, this function always fails with "
+        "operation_not_supported when used on Windows XP, Windows Server 2003, "
+        "or earlier. Consult documentation for details."))
+#endif
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is at the out-of-band data mark.
+  /**
+   * This function is used to check whether the socket input is currently
+   * positioned at the out-of-band data mark.
+   *
+   * @return A bool indicating whether the socket is at the out-of-band data
+   * mark.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  bool at_mark() const
+  {
+    asio::error_code ec;
+    bool b = this->get_service().at_mark(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "at_mark");
+    return b;
+  }
+
+  /// Determine whether the socket is at the out-of-band data mark.
+  /**
+   * This function is used to check whether the socket input is currently
+   * positioned at the out-of-band data mark.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return A bool indicating whether the socket is at the out-of-band data
+   * mark.
+   */
+  bool at_mark(asio::error_code& ec) const
+  {
+    return this->get_service().at_mark(this->get_implementation(), ec);
+  }
+
+  /// Determine the number of bytes available for reading.
+  /**
+   * This function is used to determine the number of bytes that may be read
+   * without blocking.
+   *
+   * @return The number of bytes that may be read without blocking, or 0 if an
+   * error occurs.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  std::size_t available() const
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().available(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "available");
+    return s;
+  }
+
+  /// Determine the number of bytes available for reading.
+  /**
+   * This function is used to determine the number of bytes that may be read
+   * without blocking.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of bytes that may be read without blocking, or 0 if an
+   * error occurs.
+   */
+  std::size_t available(asio::error_code& ec) const
+  {
+    return this->get_service().available(this->get_implementation(), ec);
+  }
+
+  /// Bind the socket to the given local endpoint.
+  /**
+   * This function binds the socket to the specified endpoint on the local
+   * machine.
+   *
+   * @param endpoint An endpoint on the local machine to which the socket will
+   * be bound.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * socket.open(asio::ip::tcp::v4());
+   * socket.bind(asio::ip::tcp::endpoint(
+   *       asio::ip::tcp::v4(), 12345));
+   * @endcode
+   */
+  void bind(const endpoint_type& endpoint)
+  {
+    asio::error_code ec;
+    this->get_service().bind(this->get_implementation(), endpoint, ec);
+    asio::detail::throw_error(ec, "bind");
+  }
+
+  /// Bind the socket to the given local endpoint.
+  /**
+   * This function binds the socket to the specified endpoint on the local
+   * machine.
+   *
+   * @param endpoint An endpoint on the local machine to which the socket will
+   * be bound.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * socket.open(asio::ip::tcp::v4());
+   * asio::error_code ec;
+   * socket.bind(asio::ip::tcp::endpoint(
+   *       asio::ip::tcp::v4(), 12345), ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID bind(const endpoint_type& endpoint,
+      asio::error_code& ec)
+  {
+    this->get_service().bind(this->get_implementation(), endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Connect the socket to the specified endpoint.
+  /**
+   * This function is used to connect a socket to the specified remote endpoint.
+   * The function call will block until the connection is successfully made or
+   * an error occurs.
+   *
+   * The socket is automatically opened if it is not already open. If the
+   * connect fails, and the socket was automatically opened, the socket is
+   * not returned to the closed state.
+   *
+   * @param peer_endpoint The remote endpoint to which the socket will be
+   * connected.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * asio::ip::tcp::endpoint endpoint(
+   *     asio::ip::address::from_string("1.2.3.4"), 12345);
+   * socket.connect(endpoint);
+   * @endcode
+   */
+  void connect(const endpoint_type& peer_endpoint)
+  {
+    asio::error_code ec;
+    if (!is_open())
+    {
+      this->get_service().open(this->get_implementation(),
+          peer_endpoint.protocol(), ec);
+      asio::detail::throw_error(ec, "connect");
+    }
+    this->get_service().connect(this->get_implementation(), peer_endpoint, ec);
+    asio::detail::throw_error(ec, "connect");
+  }
+
+  /// Connect the socket to the specified endpoint.
+  /**
+   * This function is used to connect a socket to the specified remote endpoint.
+   * The function call will block until the connection is successfully made or
+   * an error occurs.
+   *
+   * The socket is automatically opened if it is not already open. If the
+   * connect fails, and the socket was automatically opened, the socket is
+   * not returned to the closed state.
+   *
+   * @param peer_endpoint The remote endpoint to which the socket will be
+   * connected.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * asio::ip::tcp::endpoint endpoint(
+   *     asio::ip::address::from_string("1.2.3.4"), 12345);
+   * asio::error_code ec;
+   * socket.connect(endpoint, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID connect(const endpoint_type& peer_endpoint,
+      asio::error_code& ec)
+  {
+    if (!is_open())
+    {
+      this->get_service().open(this->get_implementation(),
+            peer_endpoint.protocol(), ec);
+      if (ec)
+      {
+        ASIO_SYNC_OP_VOID_RETURN(ec);
+      }
+    }
+
+    this->get_service().connect(this->get_implementation(), peer_endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous connect.
+  /**
+   * This function is used to asynchronously connect a socket to the specified
+   * remote endpoint. The function call always returns immediately.
+   *
+   * The socket is automatically opened if it is not already open. If the
+   * connect fails, and the socket was automatically opened, the socket is
+   * not returned to the closed state.
+   *
+   * @param peer_endpoint The remote endpoint to which the socket will be
+   * connected. Copies will be made of the endpoint object as required.
+   *
+   * @param handler The handler to be called when the connection operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void connect_handler(const asio::error_code& error)
+   * {
+   *   if (!error)
+   *   {
+   *     // Connect succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::socket socket(io_context);
+   * asio::ip::tcp::endpoint endpoint(
+   *     asio::ip::address::from_string("1.2.3.4"), 12345);
+   * socket.async_connect(endpoint, connect_handler);
+   * @endcode
+   */
+  template <typename ConnectHandler>
+  ASIO_INITFN_RESULT_TYPE(ConnectHandler,
+      void (asio::error_code))
+  async_connect(const endpoint_type& peer_endpoint,
+      ASIO_MOVE_ARG(ConnectHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ConnectHandler.
+    ASIO_CONNECT_HANDLER_CHECK(ConnectHandler, handler) type_check;
+
+    if (!is_open())
+    {
+      asio::error_code ec;
+      const protocol_type protocol = peer_endpoint.protocol();
+      this->get_service().open(this->get_implementation(), protocol, ec);
+      if (ec)
+      {
+        async_completion<ConnectHandler,
+          void (asio::error_code)> init(handler);
+
+        asio::post(this->get_executor(),
+            asio::detail::bind_handler(
+              ASIO_MOVE_CAST(ASIO_HANDLER_TYPE(
+                ConnectHandler, void (asio::error_code)))(
+                  init.completion_handler), ec));
+
+        return init.result.get();
+      }
+    }
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_connect(this->get_implementation(),
+        peer_endpoint, ASIO_MOVE_CAST(ConnectHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ConnectHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_connect(
+        this->get_implementation(), peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Set an option on the socket.
+  /**
+   * This function is used to set an option on the socket.
+   *
+   * @param option The new option value to be set on the socket.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa SettableSocketOption @n
+   * asio::socket_base::broadcast @n
+   * asio::socket_base::do_not_route @n
+   * asio::socket_base::keep_alive @n
+   * asio::socket_base::linger @n
+   * asio::socket_base::receive_buffer_size @n
+   * asio::socket_base::receive_low_watermark @n
+   * asio::socket_base::reuse_address @n
+   * asio::socket_base::send_buffer_size @n
+   * asio::socket_base::send_low_watermark @n
+   * asio::ip::multicast::join_group @n
+   * asio::ip::multicast::leave_group @n
+   * asio::ip::multicast::enable_loopback @n
+   * asio::ip::multicast::outbound_interface @n
+   * asio::ip::multicast::hops @n
+   * asio::ip::tcp::no_delay
+   *
+   * @par Example
+   * Setting the IPPROTO_TCP/TCP_NODELAY option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::no_delay option(true);
+   * socket.set_option(option);
+   * @endcode
+   */
+  template <typename SettableSocketOption>
+  void set_option(const SettableSocketOption& option)
+  {
+    asio::error_code ec;
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "set_option");
+  }
+
+  /// Set an option on the socket.
+  /**
+   * This function is used to set an option on the socket.
+   *
+   * @param option The new option value to be set on the socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa SettableSocketOption @n
+   * asio::socket_base::broadcast @n
+   * asio::socket_base::do_not_route @n
+   * asio::socket_base::keep_alive @n
+   * asio::socket_base::linger @n
+   * asio::socket_base::receive_buffer_size @n
+   * asio::socket_base::receive_low_watermark @n
+   * asio::socket_base::reuse_address @n
+   * asio::socket_base::send_buffer_size @n
+   * asio::socket_base::send_low_watermark @n
+   * asio::ip::multicast::join_group @n
+   * asio::ip::multicast::leave_group @n
+   * asio::ip::multicast::enable_loopback @n
+   * asio::ip::multicast::outbound_interface @n
+   * asio::ip::multicast::hops @n
+   * asio::ip::tcp::no_delay
+   *
+   * @par Example
+   * Setting the IPPROTO_TCP/TCP_NODELAY option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::no_delay option(true);
+   * asio::error_code ec;
+   * socket.set_option(option, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  template <typename SettableSocketOption>
+  ASIO_SYNC_OP_VOID set_option(const SettableSocketOption& option,
+      asio::error_code& ec)
+  {
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get an option from the socket.
+  /**
+   * This function is used to get the current value of an option on the socket.
+   *
+   * @param option The option value to be obtained from the socket.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa GettableSocketOption @n
+   * asio::socket_base::broadcast @n
+   * asio::socket_base::do_not_route @n
+   * asio::socket_base::keep_alive @n
+   * asio::socket_base::linger @n
+   * asio::socket_base::receive_buffer_size @n
+   * asio::socket_base::receive_low_watermark @n
+   * asio::socket_base::reuse_address @n
+   * asio::socket_base::send_buffer_size @n
+   * asio::socket_base::send_low_watermark @n
+   * asio::ip::multicast::join_group @n
+   * asio::ip::multicast::leave_group @n
+   * asio::ip::multicast::enable_loopback @n
+   * asio::ip::multicast::outbound_interface @n
+   * asio::ip::multicast::hops @n
+   * asio::ip::tcp::no_delay
+   *
+   * @par Example
+   * Getting the value of the SOL_SOCKET/SO_KEEPALIVE option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::socket::keep_alive option;
+   * socket.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   */
+  template <typename GettableSocketOption>
+  void get_option(GettableSocketOption& option) const
+  {
+    asio::error_code ec;
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "get_option");
+  }
+
+  /// Get an option from the socket.
+  /**
+   * This function is used to get the current value of an option on the socket.
+   *
+   * @param option The option value to be obtained from the socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa GettableSocketOption @n
+   * asio::socket_base::broadcast @n
+   * asio::socket_base::do_not_route @n
+   * asio::socket_base::keep_alive @n
+   * asio::socket_base::linger @n
+   * asio::socket_base::receive_buffer_size @n
+   * asio::socket_base::receive_low_watermark @n
+   * asio::socket_base::reuse_address @n
+   * asio::socket_base::send_buffer_size @n
+   * asio::socket_base::send_low_watermark @n
+   * asio::ip::multicast::join_group @n
+   * asio::ip::multicast::leave_group @n
+   * asio::ip::multicast::enable_loopback @n
+   * asio::ip::multicast::outbound_interface @n
+   * asio::ip::multicast::hops @n
+   * asio::ip::tcp::no_delay
+   *
+   * @par Example
+   * Getting the value of the SOL_SOCKET/SO_KEEPALIVE option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::socket::keep_alive option;
+   * asio::error_code ec;
+   * socket.get_option(option, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * bool is_set = option.value();
+   * @endcode
+   */
+  template <typename GettableSocketOption>
+  ASIO_SYNC_OP_VOID get_option(GettableSocketOption& option,
+      asio::error_code& ec) const
+  {
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the socket.
+  /**
+   * This function is used to execute an IO control command on the socket.
+   *
+   * @param command The IO control command to be performed on the socket.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa IoControlCommand @n
+   * asio::socket_base::bytes_readable @n
+   * asio::socket_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::socket::bytes_readable command;
+   * socket.io_control(command);
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  void io_control(IoControlCommand& command)
+  {
+    asio::error_code ec;
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    asio::detail::throw_error(ec, "io_control");
+  }
+
+  /// Perform an IO control command on the socket.
+  /**
+   * This function is used to execute an IO control command on the socket.
+   *
+   * @param command The IO control command to be performed on the socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa IoControlCommand @n
+   * asio::socket_base::bytes_readable @n
+   * asio::socket_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::socket::bytes_readable command;
+   * asio::error_code ec;
+   * socket.io_control(command, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(IoControlCommand& command,
+      asio::error_code& ec)
+  {
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the socket.
+  /**
+   * @returns @c true if the socket's synchronous operations will fail with
+   * asio::error::would_block if they are unable to perform the requested
+   * operation immediately. If @c false, synchronous operations will block
+   * until complete.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  bool non_blocking() const
+  {
+    return this->get_service().non_blocking(this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the socket.
+  /**
+   * @param mode If @c true, the socket's synchronous operations will fail with
+   * asio::error::would_block if they are unable to perform the requested
+   * operation immediately. If @c false, synchronous operations will block
+   * until complete.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  void non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the socket.
+  /**
+   * @param mode If @c true, the socket's synchronous operations will fail with
+   * asio::error::would_block if they are unable to perform the requested
+   * operation immediately. If @c false, synchronous operations will block
+   * until complete.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  ASIO_SYNC_OP_VOID non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native socket implementation.
+  /**
+   * This function is used to retrieve the non-blocking mode of the underlying
+   * native socket. This mode has no effect on the behaviour of the socket
+   * object's synchronous operations.
+   *
+   * @returns @c true if the underlying socket is in non-blocking mode and
+   * direct system calls may fail with asio::error::would_block (or the
+   * equivalent system error).
+   *
+   * @note The current non-blocking mode is cached by the socket object.
+   * Consequently, the return value may be incorrect if the non-blocking mode
+   * was set directly on the native socket.
+   *
+   * @par Example
+   * This function is intended to allow the encapsulation of arbitrary
+   * non-blocking system calls as asynchronous operations, in a way that is
+   * transparent to the user of the socket object. The following example
+   * illustrates how Linux's @c sendfile system call might be encapsulated:
+   * @code template <typename Handler>
+   * struct sendfile_op
+   * {
+   *   tcp::socket& sock_;
+   *   int fd_;
+   *   Handler handler_;
+   *   off_t offset_;
+   *   std::size_t total_bytes_transferred_;
+   *
+   *   // Function call operator meeting WriteHandler requirements.
+   *   // Used as the handler for the async_write_some operation.
+   *   void operator()(asio::error_code ec, std::size_t)
+   *   {
+   *     // Put the underlying socket into non-blocking mode.
+   *     if (!ec)
+   *       if (!sock_.native_non_blocking())
+   *         sock_.native_non_blocking(true, ec);
+   *
+   *     if (!ec)
+   *     {
+   *       for (;;)
+   *       {
+   *         // Try the system call.
+   *         errno = 0;
+   *         int n = ::sendfile(sock_.native_handle(), fd_, &offset_, 65536);
+   *         ec = asio::error_code(n < 0 ? errno : 0,
+   *             asio::error::get_system_category());
+   *         total_bytes_transferred_ += ec ? 0 : n;
+   *
+   *         // Retry operation immediately if interrupted by signal.
+   *         if (ec == asio::error::interrupted)
+   *           continue;
+   *
+   *         // Check if we need to run the operation again.
+   *         if (ec == asio::error::would_block
+   *             || ec == asio::error::try_again)
+   *         {
+   *           // We have to wait for the socket to become ready again.
+   *           sock_.async_wait(tcp::socket::wait_write, *this);
+   *           return;
+   *         }
+   *
+   *         if (ec || n == 0)
+   *         {
+   *           // An error occurred, or we have reached the end of the file.
+   *           // Either way we must exit the loop so we can call the handler.
+   *           break;
+   *         }
+   *
+   *         // Loop around to try calling sendfile again.
+   *       }
+   *     }
+   *
+   *     // Pass result back to user's handler.
+   *     handler_(ec, total_bytes_transferred_);
+   *   }
+   * };
+   *
+   * template <typename Handler>
+   * void async_sendfile(tcp::socket& sock, int fd, Handler h)
+   * {
+   *   sendfile_op<Handler> op = { sock, fd, h, 0, 0 };
+   *   sock.async_wait(tcp::socket::wait_write, op);
+   * } @endcode
+   */
+  bool native_non_blocking() const
+  {
+    return this->get_service().native_non_blocking(this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the native socket implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native socket. It has no effect on the behaviour of the socket object's
+   * synchronous operations.
+   *
+   * @param mode If @c true, the underlying socket is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @throws asio::system_error Thrown on failure. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   *
+   * @par Example
+   * This function is intended to allow the encapsulation of arbitrary
+   * non-blocking system calls as asynchronous operations, in a way that is
+   * transparent to the user of the socket object. The following example
+   * illustrates how Linux's @c sendfile system call might be encapsulated:
+   * @code template <typename Handler>
+   * struct sendfile_op
+   * {
+   *   tcp::socket& sock_;
+   *   int fd_;
+   *   Handler handler_;
+   *   off_t offset_;
+   *   std::size_t total_bytes_transferred_;
+   *
+   *   // Function call operator meeting WriteHandler requirements.
+   *   // Used as the handler for the async_write_some operation.
+   *   void operator()(asio::error_code ec, std::size_t)
+   *   {
+   *     // Put the underlying socket into non-blocking mode.
+   *     if (!ec)
+   *       if (!sock_.native_non_blocking())
+   *         sock_.native_non_blocking(true, ec);
+   *
+   *     if (!ec)
+   *     {
+   *       for (;;)
+   *       {
+   *         // Try the system call.
+   *         errno = 0;
+   *         int n = ::sendfile(sock_.native_handle(), fd_, &offset_, 65536);
+   *         ec = asio::error_code(n < 0 ? errno : 0,
+   *             asio::error::get_system_category());
+   *         total_bytes_transferred_ += ec ? 0 : n;
+   *
+   *         // Retry operation immediately if interrupted by signal.
+   *         if (ec == asio::error::interrupted)
+   *           continue;
+   *
+   *         // Check if we need to run the operation again.
+   *         if (ec == asio::error::would_block
+   *             || ec == asio::error::try_again)
+   *         {
+   *           // We have to wait for the socket to become ready again.
+   *           sock_.async_wait(tcp::socket::wait_write, *this);
+   *           return;
+   *         }
+   *
+   *         if (ec || n == 0)
+   *         {
+   *           // An error occurred, or we have reached the end of the file.
+   *           // Either way we must exit the loop so we can call the handler.
+   *           break;
+   *         }
+   *
+   *         // Loop around to try calling sendfile again.
+   *       }
+   *     }
+   *
+   *     // Pass result back to user's handler.
+   *     handler_(ec, total_bytes_transferred_);
+   *   }
+   * };
+   *
+   * template <typename Handler>
+   * void async_sendfile(tcp::socket& sock, int fd, Handler h)
+   * {
+   *   sendfile_op<Handler> op = { sock, fd, h, 0, 0 };
+   *   sock.async_wait(tcp::socket::wait_write, op);
+   * } @endcode
+   */
+  void native_non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "native_non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the native socket implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native socket. It has no effect on the behaviour of the socket object's
+   * synchronous operations.
+   *
+   * @param mode If @c true, the underlying socket is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @param ec Set to indicate what error occurred, if any. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   *
+   * @par Example
+   * This function is intended to allow the encapsulation of arbitrary
+   * non-blocking system calls as asynchronous operations, in a way that is
+   * transparent to the user of the socket object. The following example
+   * illustrates how Linux's @c sendfile system call might be encapsulated:
+   * @code template <typename Handler>
+   * struct sendfile_op
+   * {
+   *   tcp::socket& sock_;
+   *   int fd_;
+   *   Handler handler_;
+   *   off_t offset_;
+   *   std::size_t total_bytes_transferred_;
+   *
+   *   // Function call operator meeting WriteHandler requirements.
+   *   // Used as the handler for the async_write_some operation.
+   *   void operator()(asio::error_code ec, std::size_t)
+   *   {
+   *     // Put the underlying socket into non-blocking mode.
+   *     if (!ec)
+   *       if (!sock_.native_non_blocking())
+   *         sock_.native_non_blocking(true, ec);
+   *
+   *     if (!ec)
+   *     {
+   *       for (;;)
+   *       {
+   *         // Try the system call.
+   *         errno = 0;
+   *         int n = ::sendfile(sock_.native_handle(), fd_, &offset_, 65536);
+   *         ec = asio::error_code(n < 0 ? errno : 0,
+   *             asio::error::get_system_category());
+   *         total_bytes_transferred_ += ec ? 0 : n;
+   *
+   *         // Retry operation immediately if interrupted by signal.
+   *         if (ec == asio::error::interrupted)
+   *           continue;
+   *
+   *         // Check if we need to run the operation again.
+   *         if (ec == asio::error::would_block
+   *             || ec == asio::error::try_again)
+   *         {
+   *           // We have to wait for the socket to become ready again.
+   *           sock_.async_wait(tcp::socket::wait_write, *this);
+   *           return;
+   *         }
+   *
+   *         if (ec || n == 0)
+   *         {
+   *           // An error occurred, or we have reached the end of the file.
+   *           // Either way we must exit the loop so we can call the handler.
+   *           break;
+   *         }
+   *
+   *         // Loop around to try calling sendfile again.
+   *       }
+   *     }
+   *
+   *     // Pass result back to user's handler.
+   *     handler_(ec, total_bytes_transferred_);
+   *   }
+   * };
+   *
+   * template <typename Handler>
+   * void async_sendfile(tcp::socket& sock, int fd, Handler h)
+   * {
+   *   sendfile_op<Handler> op = { sock, fd, h, 0, 0 };
+   *   sock.async_wait(tcp::socket::wait_write, op);
+   * } @endcode
+   */
+  ASIO_SYNC_OP_VOID native_non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the local endpoint of the socket.
+  /**
+   * This function is used to obtain the locally bound endpoint of the socket.
+   *
+   * @returns An object that represents the local endpoint of the socket.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint = socket.local_endpoint();
+   * @endcode
+   */
+  endpoint_type local_endpoint() const
+  {
+    asio::error_code ec;
+    endpoint_type ep = this->get_service().local_endpoint(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "local_endpoint");
+    return ep;
+  }
+
+  /// Get the local endpoint of the socket.
+  /**
+   * This function is used to obtain the locally bound endpoint of the socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns An object that represents the local endpoint of the socket.
+   * Returns a default-constructed endpoint object if an error occurred.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::error_code ec;
+   * asio::ip::tcp::endpoint endpoint = socket.local_endpoint(ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  endpoint_type local_endpoint(asio::error_code& ec) const
+  {
+    return this->get_service().local_endpoint(this->get_implementation(), ec);
+  }
+
+  /// Get the remote endpoint of the socket.
+  /**
+   * This function is used to obtain the remote endpoint of the socket.
+   *
+   * @returns An object that represents the remote endpoint of the socket.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint = socket.remote_endpoint();
+   * @endcode
+   */
+  endpoint_type remote_endpoint() const
+  {
+    asio::error_code ec;
+    endpoint_type ep = this->get_service().remote_endpoint(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "remote_endpoint");
+    return ep;
+  }
+
+  /// Get the remote endpoint of the socket.
+  /**
+   * This function is used to obtain the remote endpoint of the socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns An object that represents the remote endpoint of the socket.
+   * Returns a default-constructed endpoint object if an error occurred.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::error_code ec;
+   * asio::ip::tcp::endpoint endpoint = socket.remote_endpoint(ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  endpoint_type remote_endpoint(asio::error_code& ec) const
+  {
+    return this->get_service().remote_endpoint(this->get_implementation(), ec);
+  }
+
+  /// Disable sends or receives on the socket.
+  /**
+   * This function is used to disable send operations, receive operations, or
+   * both.
+   *
+   * @param what Determines what types of operation will no longer be allowed.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * Shutting down the send side of the socket:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * socket.shutdown(asio::ip::tcp::socket::shutdown_send);
+   * @endcode
+   */
+  void shutdown(shutdown_type what)
+  {
+    asio::error_code ec;
+    this->get_service().shutdown(this->get_implementation(), what, ec);
+    asio::detail::throw_error(ec, "shutdown");
+  }
+
+  /// Disable sends or receives on the socket.
+  /**
+   * This function is used to disable send operations, receive operations, or
+   * both.
+   *
+   * @param what Determines what types of operation will no longer be allowed.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * Shutting down the send side of the socket:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::error_code ec;
+   * socket.shutdown(asio::ip::tcp::socket::shutdown_send, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID shutdown(shutdown_type what,
+      asio::error_code& ec)
+  {
+    this->get_service().shutdown(this->get_implementation(), what, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the socket to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for a socket to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired socket state.
+   *
+   * @par Example
+   * Waiting for a socket to become readable.
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * socket.wait(asio::ip::tcp::socket::wait_read);
+   * @endcode
+   */
+  void wait(wait_type w)
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), w, ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Wait for the socket to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for a socket to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired socket state.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * Waiting for a socket to become readable.
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::error_code ec;
+   * socket.wait(asio::ip::tcp::socket::wait_read, ec);
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID wait(wait_type w, asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the socket to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  /**
+   * This function is used to perform an asynchronous wait for a socket to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired socket state.
+   *
+   * @param handler The handler to be called when the wait operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void wait_handler(const asio::error_code& error)
+   * {
+   *   if (!error)
+   *   {
+   *     // Wait succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * socket.async_wait(asio::ip::tcp::socket::wait_read, wait_handler);
+   * @endcode
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(wait_type w, ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WaitHandler.
+    ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_wait(this->get_implementation(),
+        w, ASIO_MOVE_CAST(WaitHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_wait(this->get_implementation(),
+        w, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  /**
+   * This function destroys the socket, cancelling any outstanding asynchronous
+   * operations associated with the socket as if by calling @c cancel.
+   */
+  ~basic_socket()
+  {
+  }
+
+private:
+  // Disallow copying and assignment.
+  basic_socket(const basic_socket&) ASIO_DELETED;
+  basic_socket& operator=(const basic_socket&) ASIO_DELETED;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# undef ASIO_SVC_T
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_BASIC_SOCKET_HPP
diff --git a/subprojects/asio/include/asio/basic_socket_acceptor.hpp b/subprojects/asio/include/asio/basic_socket_acceptor.hpp
new file mode 100644
index 000000000..ed201bbca
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_socket_acceptor.hpp
@@ -0,0 +1,1986 @@
+//
+// basic_socket_acceptor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_SOCKET_ACCEPTOR_HPP
+#define ASIO_BASIC_SOCKET_ACCEPTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/basic_socket.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/socket_base.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/socket_acceptor_service.hpp"
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+# if defined(ASIO_WINDOWS_RUNTIME)
+#  include "asio/detail/null_socket_service.hpp"
+#  define ASIO_SVC_T detail::null_socket_service<Protocol>
+# elif defined(ASIO_HAS_IOCP)
+#  include "asio/detail/win_iocp_socket_service.hpp"
+#  define ASIO_SVC_T detail::win_iocp_socket_service<Protocol>
+# else
+#  include "asio/detail/reactive_socket_service.hpp"
+#  define ASIO_SVC_T detail::reactive_socket_service<Protocol>
+# endif
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides the ability to accept new connections.
+/**
+ * The basic_socket_acceptor class template is used for accepting new socket
+ * connections.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Example
+ * Opening a socket acceptor with the SO_REUSEADDR option enabled:
+ * @code
+ * asio::ip::tcp::acceptor acceptor(io_context);
+ * asio::ip::tcp::endpoint endpoint(asio::ip::tcp::v4(), port);
+ * acceptor.open(endpoint.protocol());
+ * acceptor.set_option(asio::ip::tcp::acceptor::reuse_address(true));
+ * acceptor.bind(endpoint);
+ * acceptor.listen();
+ * @endcode
+ */
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= socket_acceptor_service<Protocol>)>
+class basic_socket_acceptor
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>,
+    public socket_base
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The native representation of an acceptor.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename ASIO_SVC_T::native_handle_type native_handle_type;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  /// Construct an acceptor without opening it.
+  /**
+   * This constructor creates an acceptor without opening it to listen for new
+   * connections. The open() function must be called before the acceptor can
+   * accept new socket connections.
+   *
+   * @param io_context The io_context object that the acceptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * acceptor.
+   */
+  explicit basic_socket_acceptor(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Construct an open acceptor.
+  /**
+   * This constructor creates an acceptor and automatically opens it.
+   *
+   * @param io_context The io_context object that the acceptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * acceptor.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_socket_acceptor(asio::io_context& io_context,
+      const protocol_type& protocol)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Construct an acceptor opened on the given endpoint.
+  /**
+   * This constructor creates an acceptor and automatically opens it to listen
+   * for new connections on the specified endpoint.
+   *
+   * @param io_context The io_context object that the acceptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * acceptor.
+   *
+   * @param endpoint An endpoint on the local machine on which the acceptor
+   * will listen for new connections.
+   *
+   * @param reuse_addr Whether the constructor should set the socket option
+   * socket_base::reuse_address.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note This constructor is equivalent to the following code:
+   * @code
+   * basic_socket_acceptor<Protocol> acceptor(io_context);
+   * acceptor.open(endpoint.protocol());
+   * if (reuse_addr)
+   *   acceptor.set_option(socket_base::reuse_address(true));
+   * acceptor.bind(endpoint);
+   * acceptor.listen(listen_backlog);
+   * @endcode
+   */
+  basic_socket_acceptor(asio::io_context& io_context,
+      const endpoint_type& endpoint, bool reuse_addr = true)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    const protocol_type protocol = endpoint.protocol();
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    asio::detail::throw_error(ec, "open");
+    if (reuse_addr)
+    {
+      this->get_service().set_option(this->get_implementation(),
+          socket_base::reuse_address(true), ec);
+      asio::detail::throw_error(ec, "set_option");
+    }
+    this->get_service().bind(this->get_implementation(), endpoint, ec);
+    asio::detail::throw_error(ec, "bind");
+    this->get_service().listen(this->get_implementation(),
+        socket_base::max_listen_connections, ec);
+    asio::detail::throw_error(ec, "listen");
+  }
+
+  /// Construct a basic_socket_acceptor on an existing native acceptor.
+  /**
+   * This constructor creates an acceptor object to hold an existing native
+   * acceptor.
+   *
+   * @param io_context The io_context object that the acceptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * acceptor.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @param native_acceptor A native acceptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_socket_acceptor(asio::io_context& io_context,
+      const protocol_type& protocol, const native_handle_type& native_acceptor)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        protocol, native_acceptor, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_socket_acceptor from another.
+  /**
+   * This constructor moves an acceptor from one object to another.
+   *
+   * @param other The other basic_socket_acceptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket_acceptor(io_context&) constructor.
+   */
+  basic_socket_acceptor(basic_socket_acceptor&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_socket_acceptor from another.
+  /**
+   * This assignment operator moves an acceptor from one object to another.
+   *
+   * @param other The other basic_socket_acceptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket_acceptor(io_context&) constructor.
+   */
+  basic_socket_acceptor& operator=(basic_socket_acceptor&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+
+  // All socket acceptors have access to each other's implementations.
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  friend class basic_socket_acceptor;
+
+  /// Move-construct a basic_socket_acceptor from an acceptor of another
+  /// protocol type.
+  /**
+   * This constructor moves an acceptor from one object to another.
+   *
+   * @param other The other basic_socket_acceptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  basic_socket_acceptor(
+      basic_socket_acceptor<Protocol1 ASIO_SVC_TARG1>&& other,
+      typename enable_if<is_convertible<Protocol1, Protocol>::value>::type* = 0)
+    : basic_io_object<ASIO_SVC_T>(
+        other.get_service(), other.get_implementation())
+  {
+  }
+
+  /// Move-assign a basic_socket_acceptor from an acceptor of another protocol
+  /// type.
+  /**
+   * This assignment operator moves an acceptor from one object to another.
+   *
+   * @param other The other basic_socket_acceptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  typename enable_if<is_convertible<Protocol1, Protocol>::value,
+      basic_socket_acceptor>::type& operator=(
+        basic_socket_acceptor<Protocol1 ASIO_SVC_TARG1>&& other)
+  {
+    basic_socket_acceptor tmp(std::move(other));
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(tmp));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the acceptor.
+  /**
+   * This function destroys the acceptor, cancelling any outstanding
+   * asynchronous operations associated with the acceptor as if by calling
+   * @c cancel.
+   */
+  ~basic_socket_acceptor()
+  {
+  }
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  // These functions are provided by basic_io_object<>.
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+  /// Open the acceptor using the specified protocol.
+  /**
+   * This function opens the socket acceptor so that it will use the specified
+   * protocol.
+   *
+   * @param protocol An object specifying which protocol is to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * acceptor.open(asio::ip::tcp::v4());
+   * @endcode
+   */
+  void open(const protocol_type& protocol = protocol_type())
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Open the acceptor using the specified protocol.
+  /**
+   * This function opens the socket acceptor so that it will use the specified
+   * protocol.
+   *
+   * @param protocol An object specifying which protocol is to be used.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * asio::error_code ec;
+   * acceptor.open(asio::ip::tcp::v4(), ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID open(const protocol_type& protocol,
+      asio::error_code& ec)
+  {
+    this->get_service().open(this->get_implementation(), protocol, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assigns an existing native acceptor to the acceptor.
+  /*
+   * This function opens the acceptor to hold an existing native acceptor.
+   *
+   * @param protocol An object specifying which protocol is to be used.
+   *
+   * @param native_acceptor A native acceptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const protocol_type& protocol,
+      const native_handle_type& native_acceptor)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        protocol, native_acceptor, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assigns an existing native acceptor to the acceptor.
+  /*
+   * This function opens the acceptor to hold an existing native acceptor.
+   *
+   * @param protocol An object specifying which protocol is to be used.
+   *
+   * @param native_acceptor A native acceptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const protocol_type& protocol,
+      const native_handle_type& native_acceptor, asio::error_code& ec)
+  {
+    this->get_service().assign(this->get_implementation(),
+        protocol, native_acceptor, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the acceptor is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Bind the acceptor to the given local endpoint.
+  /**
+   * This function binds the socket acceptor to the specified endpoint on the
+   * local machine.
+   *
+   * @param endpoint An endpoint on the local machine to which the socket
+   * acceptor will be bound.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * asio::ip::tcp::endpoint endpoint(asio::ip::tcp::v4(), 12345);
+   * acceptor.open(endpoint.protocol());
+   * acceptor.bind(endpoint);
+   * @endcode
+   */
+  void bind(const endpoint_type& endpoint)
+  {
+    asio::error_code ec;
+    this->get_service().bind(this->get_implementation(), endpoint, ec);
+    asio::detail::throw_error(ec, "bind");
+  }
+
+  /// Bind the acceptor to the given local endpoint.
+  /**
+   * This function binds the socket acceptor to the specified endpoint on the
+   * local machine.
+   *
+   * @param endpoint An endpoint on the local machine to which the socket
+   * acceptor will be bound.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * asio::ip::tcp::endpoint endpoint(asio::ip::tcp::v4(), 12345);
+   * acceptor.open(endpoint.protocol());
+   * asio::error_code ec;
+   * acceptor.bind(endpoint, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID bind(const endpoint_type& endpoint,
+      asio::error_code& ec)
+  {
+    this->get_service().bind(this->get_implementation(), endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Place the acceptor into the state where it will listen for new
+  /// connections.
+  /**
+   * This function puts the socket acceptor into the state where it may accept
+   * new connections.
+   *
+   * @param backlog The maximum length of the queue of pending connections.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void listen(int backlog = socket_base::max_listen_connections)
+  {
+    asio::error_code ec;
+    this->get_service().listen(this->get_implementation(), backlog, ec);
+    asio::detail::throw_error(ec, "listen");
+  }
+
+  /// Place the acceptor into the state where it will listen for new
+  /// connections.
+  /**
+   * This function puts the socket acceptor into the state where it may accept
+   * new connections.
+   *
+   * @param backlog The maximum length of the queue of pending connections.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::error_code ec;
+   * acceptor.listen(asio::socket_base::max_listen_connections, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID listen(int backlog, asio::error_code& ec)
+  {
+    this->get_service().listen(this->get_implementation(), backlog, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Close the acceptor.
+  /**
+   * This function is used to close the acceptor. Any asynchronous accept
+   * operations will be cancelled immediately.
+   *
+   * A subsequent call to open() is required before the acceptor can again be
+   * used to again perform socket accept operations.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the acceptor.
+  /**
+   * This function is used to close the acceptor. Any asynchronous accept
+   * operations will be cancelled immediately.
+   *
+   * A subsequent call to open() is required before the acceptor can again be
+   * used to again perform socket accept operations.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::error_code ec;
+   * acceptor.close(ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Release ownership of the underlying native acceptor.
+  /**
+   * This function causes all outstanding asynchronous accept operations to
+   * finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error. Ownership of the
+   * native acceptor is then transferred to the caller.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note This function is unsupported on Windows versions prior to Windows
+   * 8.1, and will fail with asio::error::operation_not_supported on
+   * these platforms.
+   */
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1400) \
+  && (!defined(_WIN32_WINNT) || _WIN32_WINNT < 0x0603)
+  __declspec(deprecated("This function always fails with "
+        "operation_not_supported when used on Windows versions "
+        "prior to Windows 8.1."))
+#endif
+  native_handle_type release()
+  {
+    asio::error_code ec;
+    native_handle_type s = this->get_service().release(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "release");
+    return s;
+  }
+
+  /// Release ownership of the underlying native acceptor.
+  /**
+   * This function causes all outstanding asynchronous accept operations to
+   * finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error. Ownership of the
+   * native acceptor is then transferred to the caller.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note This function is unsupported on Windows versions prior to Windows
+   * 8.1, and will fail with asio::error::operation_not_supported on
+   * these platforms.
+   */
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1400) \
+  && (!defined(_WIN32_WINNT) || _WIN32_WINNT < 0x0603)
+  __declspec(deprecated("This function always fails with "
+        "operation_not_supported when used on Windows versions "
+        "prior to Windows 8.1."))
+#endif
+  native_handle_type release(asio::error_code& ec)
+  {
+    return this->get_service().release(this->get_implementation(), ec);
+  }
+
+  /// Get the native acceptor representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * acceptor. This is intended to allow access to native acceptor functionality
+   * that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the acceptor.
+  /**
+   * This function causes all outstanding asynchronous connect, send and receive
+   * operations to finish immediately, and the handlers for cancelled operations
+   * will be passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the acceptor.
+  /**
+   * This function causes all outstanding asynchronous connect, send and receive
+   * operations to finish immediately, and the handlers for cancelled operations
+   * will be passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Set an option on the acceptor.
+  /**
+   * This function is used to set an option on the acceptor.
+   *
+   * @param option The new option value to be set on the acceptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa SettableSocketOption @n
+   * asio::socket_base::reuse_address
+   * asio::socket_base::enable_connection_aborted
+   *
+   * @par Example
+   * Setting the SOL_SOCKET/SO_REUSEADDR option:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::acceptor::reuse_address option(true);
+   * acceptor.set_option(option);
+   * @endcode
+   */
+  template <typename SettableSocketOption>
+  void set_option(const SettableSocketOption& option)
+  {
+    asio::error_code ec;
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "set_option");
+  }
+
+  /// Set an option on the acceptor.
+  /**
+   * This function is used to set an option on the acceptor.
+   *
+   * @param option The new option value to be set on the acceptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa SettableSocketOption @n
+   * asio::socket_base::reuse_address
+   * asio::socket_base::enable_connection_aborted
+   *
+   * @par Example
+   * Setting the SOL_SOCKET/SO_REUSEADDR option:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::acceptor::reuse_address option(true);
+   * asio::error_code ec;
+   * acceptor.set_option(option, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  template <typename SettableSocketOption>
+  ASIO_SYNC_OP_VOID set_option(const SettableSocketOption& option,
+      asio::error_code& ec)
+  {
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get an option from the acceptor.
+  /**
+   * This function is used to get the current value of an option on the
+   * acceptor.
+   *
+   * @param option The option value to be obtained from the acceptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa GettableSocketOption @n
+   * asio::socket_base::reuse_address
+   *
+   * @par Example
+   * Getting the value of the SOL_SOCKET/SO_REUSEADDR option:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::acceptor::reuse_address option;
+   * acceptor.get_option(option);
+   * bool is_set = option.get();
+   * @endcode
+   */
+  template <typename GettableSocketOption>
+  void get_option(GettableSocketOption& option) const
+  {
+    asio::error_code ec;
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "get_option");
+  }
+
+  /// Get an option from the acceptor.
+  /**
+   * This function is used to get the current value of an option on the
+   * acceptor.
+   *
+   * @param option The option value to be obtained from the acceptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa GettableSocketOption @n
+   * asio::socket_base::reuse_address
+   *
+   * @par Example
+   * Getting the value of the SOL_SOCKET/SO_REUSEADDR option:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::acceptor::reuse_address option;
+   * asio::error_code ec;
+   * acceptor.get_option(option, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * bool is_set = option.get();
+   * @endcode
+   */
+  template <typename GettableSocketOption>
+  ASIO_SYNC_OP_VOID get_option(GettableSocketOption& option,
+      asio::error_code& ec) const
+  {
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the acceptor.
+  /**
+   * This function is used to execute an IO control command on the acceptor.
+   *
+   * @param command The IO control command to be performed on the acceptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa IoControlCommand @n
+   * asio::socket_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::acceptor::non_blocking_io command(true);
+   * socket.io_control(command);
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  void io_control(IoControlCommand& command)
+  {
+    asio::error_code ec;
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    asio::detail::throw_error(ec, "io_control");
+  }
+
+  /// Perform an IO control command on the acceptor.
+  /**
+   * This function is used to execute an IO control command on the acceptor.
+   *
+   * @param command The IO control command to be performed on the acceptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa IoControlCommand @n
+   * asio::socket_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::acceptor::non_blocking_io command(true);
+   * asio::error_code ec;
+   * socket.io_control(command, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(IoControlCommand& command,
+      asio::error_code& ec)
+  {
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the acceptor.
+  /**
+   * @returns @c true if the acceptor's synchronous operations will fail with
+   * asio::error::would_block if they are unable to perform the requested
+   * operation immediately. If @c false, synchronous operations will block
+   * until complete.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  bool non_blocking() const
+  {
+    return this->get_service().non_blocking(this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the acceptor.
+  /**
+   * @param mode If @c true, the acceptor's synchronous operations will fail
+   * with asio::error::would_block if they are unable to perform the
+   * requested operation immediately. If @c false, synchronous operations will
+   * block until complete.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  void non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the acceptor.
+  /**
+   * @param mode If @c true, the acceptor's synchronous operations will fail
+   * with asio::error::would_block if they are unable to perform the
+   * requested operation immediately. If @c false, synchronous operations will
+   * block until complete.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  ASIO_SYNC_OP_VOID non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native acceptor implementation.
+  /**
+   * This function is used to retrieve the non-blocking mode of the underlying
+   * native acceptor. This mode has no effect on the behaviour of the acceptor
+   * object's synchronous operations.
+   *
+   * @returns @c true if the underlying acceptor is in non-blocking mode and
+   * direct system calls may fail with asio::error::would_block (or the
+   * equivalent system error).
+   *
+   * @note The current non-blocking mode is cached by the acceptor object.
+   * Consequently, the return value may be incorrect if the non-blocking mode
+   * was set directly on the native acceptor.
+   */
+  bool native_non_blocking() const
+  {
+    return this->get_service().native_non_blocking(this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the native acceptor implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native acceptor. It has no effect on the behaviour of the acceptor object's
+   * synchronous operations.
+   *
+   * @param mode If @c true, the underlying acceptor is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @throws asio::system_error Thrown on failure. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   */
+  void native_non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "native_non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the native acceptor implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native acceptor. It has no effect on the behaviour of the acceptor object's
+   * synchronous operations.
+   *
+   * @param mode If @c true, the underlying acceptor is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @param ec Set to indicate what error occurred, if any. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   */
+  ASIO_SYNC_OP_VOID native_non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the local endpoint of the acceptor.
+  /**
+   * This function is used to obtain the locally bound endpoint of the acceptor.
+   *
+   * @returns An object that represents the local endpoint of the acceptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint = acceptor.local_endpoint();
+   * @endcode
+   */
+  endpoint_type local_endpoint() const
+  {
+    asio::error_code ec;
+    endpoint_type ep = this->get_service().local_endpoint(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "local_endpoint");
+    return ep;
+  }
+
+  /// Get the local endpoint of the acceptor.
+  /**
+   * This function is used to obtain the locally bound endpoint of the acceptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns An object that represents the local endpoint of the acceptor.
+   * Returns a default-constructed endpoint object if an error occurred and the
+   * error handler did not throw an exception.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::error_code ec;
+   * asio::ip::tcp::endpoint endpoint = acceptor.local_endpoint(ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  endpoint_type local_endpoint(asio::error_code& ec) const
+  {
+    return this->get_service().local_endpoint(this->get_implementation(), ec);
+  }
+
+  /// Wait for the acceptor to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for an acceptor to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired acceptor state.
+   *
+   * @par Example
+   * Waiting for an acceptor to become readable.
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * acceptor.wait(asio::ip::tcp::acceptor::wait_read);
+   * @endcode
+   */
+  void wait(wait_type w)
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), w, ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Wait for the acceptor to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for an acceptor to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired acceptor state.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * Waiting for an acceptor to become readable.
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::error_code ec;
+   * acceptor.wait(asio::ip::tcp::acceptor::wait_read, ec);
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID wait(wait_type w, asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the acceptor to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  /**
+   * This function is used to perform an asynchronous wait for an acceptor to
+   * enter a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired acceptor state.
+   *
+   * @param handler The handler to be called when the wait operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void wait_handler(const asio::error_code& error)
+   * {
+   *   if (!error)
+   *   {
+   *     // Wait succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * acceptor.async_wait(
+   *     asio::ip::tcp::acceptor::wait_read,
+   *     wait_handler);
+   * @endcode
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(wait_type w, ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WaitHandler.
+    ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_wait(this->get_implementation(),
+        w, ASIO_MOVE_CAST(WaitHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_wait(this->get_implementation(),
+        w, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+#if !defined(ASIO_NO_EXTENSIONS)
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer into the
+   * given socket. The function call will block until a new connection has been
+   * accepted successfully or an error occurs.
+   *
+   * @param peer The socket into which the new connection will be accepted.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(io_context);
+   * acceptor.accept(socket);
+   * @endcode
+   */
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename Protocol1, typename SocketService>
+  void accept(basic_socket<Protocol1, SocketService>& peer,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename Protocol1>
+  void accept(basic_socket<Protocol1>& peer,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  {
+    asio::error_code ec;
+    this->get_service().accept(this->get_implementation(),
+        peer, static_cast<endpoint_type*>(0), ec);
+    asio::detail::throw_error(ec, "accept");
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer into the
+   * given socket. The function call will block until a new connection has been
+   * accepted successfully or an error occurs.
+   *
+   * @param peer The socket into which the new connection will be accepted.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(io_context);
+   * asio::error_code ec;
+   * acceptor.accept(socket, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename Protocol1, typename SocketService>
+  ASIO_SYNC_OP_VOID accept(
+      basic_socket<Protocol1, SocketService>& peer,
+      asio::error_code& ec,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename Protocol1>
+  ASIO_SYNC_OP_VOID accept(
+      basic_socket<Protocol1>& peer, asio::error_code& ec,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  {
+    this->get_service().accept(this->get_implementation(),
+        peer, static_cast<endpoint_type*>(0), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous accept.
+  /**
+   * This function is used to asynchronously accept a new connection into a
+   * socket. The function call always returns immediately.
+   *
+   * @param peer The socket into which the new connection will be accepted.
+   * Ownership of the peer object is retained by the caller, which must
+   * guarantee that it is valid until the handler is called.
+   *
+   * @param handler The handler to be called when the accept operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void accept_handler(const asio::error_code& error)
+   * {
+   *   if (!error)
+   *   {
+   *     // Accept succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(io_context);
+   * acceptor.async_accept(socket, accept_handler);
+   * @endcode
+   */
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename Protocol1, typename SocketService, typename AcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(AcceptHandler,
+      void (asio::error_code))
+  async_accept(basic_socket<Protocol1, SocketService>& peer,
+      ASIO_MOVE_ARG(AcceptHandler) handler,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename Protocol1, typename AcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(AcceptHandler,
+      void (asio::error_code))
+  async_accept(basic_socket<Protocol1>& peer,
+      ASIO_MOVE_ARG(AcceptHandler) handler,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a AcceptHandler.
+    ASIO_ACCEPT_HANDLER_CHECK(AcceptHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_accept(this->get_implementation(),
+        peer, static_cast<endpoint_type*>(0),
+        ASIO_MOVE_CAST(AcceptHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<AcceptHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_accept(this->get_implementation(),
+        peer, static_cast<endpoint_type*>(0), init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Accept a new connection and obtain the endpoint of the peer
+  /**
+   * This function is used to accept a new connection from a peer into the
+   * given socket, and additionally provide the endpoint of the remote peer.
+   * The function call will block until a new connection has been accepted
+   * successfully or an error occurs.
+   *
+   * @param peer The socket into which the new connection will be accepted.
+   *
+   * @param peer_endpoint An endpoint object which will receive the endpoint of
+   * the remote peer.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(io_context);
+   * asio::ip::tcp::endpoint endpoint;
+   * acceptor.accept(socket, endpoint);
+   * @endcode
+   */
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename SocketService>
+  void accept(basic_socket<protocol_type, SocketService>& peer,
+      endpoint_type& peer_endpoint)
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+  void accept(basic_socket<protocol_type>& peer, endpoint_type& peer_endpoint)
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  {
+    asio::error_code ec;
+    this->get_service().accept(this->get_implementation(),
+        peer, &peer_endpoint, ec);
+    asio::detail::throw_error(ec, "accept");
+  }
+
+  /// Accept a new connection and obtain the endpoint of the peer
+  /**
+   * This function is used to accept a new connection from a peer into the
+   * given socket, and additionally provide the endpoint of the remote peer.
+   * The function call will block until a new connection has been accepted
+   * successfully or an error occurs.
+   *
+   * @param peer The socket into which the new connection will be accepted.
+   *
+   * @param peer_endpoint An endpoint object which will receive the endpoint of
+   * the remote peer.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(io_context);
+   * asio::ip::tcp::endpoint endpoint;
+   * asio::error_code ec;
+   * acceptor.accept(socket, endpoint, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename SocketService>
+  ASIO_SYNC_OP_VOID accept(
+      basic_socket<protocol_type, SocketService>& peer,
+      endpoint_type& peer_endpoint, asio::error_code& ec)
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+  ASIO_SYNC_OP_VOID accept(basic_socket<protocol_type>& peer,
+      endpoint_type& peer_endpoint, asio::error_code& ec)
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  {
+    this->get_service().accept(
+        this->get_implementation(), peer, &peer_endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous accept.
+  /**
+   * This function is used to asynchronously accept a new connection into a
+   * socket, and additionally obtain the endpoint of the remote peer. The
+   * function call always returns immediately.
+   *
+   * @param peer The socket into which the new connection will be accepted.
+   * Ownership of the peer object is retained by the caller, which must
+   * guarantee that it is valid until the handler is called.
+   *
+   * @param peer_endpoint An endpoint object into which the endpoint of the
+   * remote peer will be written. Ownership of the peer_endpoint object is
+   * retained by the caller, which must guarantee that it is valid until the
+   * handler is called.
+   *
+   * @param handler The handler to be called when the accept operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename SocketService, typename AcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(AcceptHandler,
+      void (asio::error_code))
+  async_accept(basic_socket<protocol_type, SocketService>& peer,
+      endpoint_type& peer_endpoint, ASIO_MOVE_ARG(AcceptHandler) handler)
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+  template <typename AcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(AcceptHandler,
+      void (asio::error_code))
+  async_accept(basic_socket<protocol_type>& peer,
+      endpoint_type& peer_endpoint, ASIO_MOVE_ARG(AcceptHandler) handler)
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a AcceptHandler.
+    ASIO_ACCEPT_HANDLER_CHECK(AcceptHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_accept(this->get_implementation(), peer,
+        &peer_endpoint, ASIO_MOVE_CAST(AcceptHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<AcceptHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_accept(this->get_implementation(),
+        peer, &peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @returns A socket object representing the newly accepted connection.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(acceptor.accept());
+   * @endcode
+   */
+  typename Protocol::socket accept()
+  {
+    asio::error_code ec;
+    typename Protocol::socket peer(
+        this->get_service().accept(
+          this->get_implementation(), 0, 0, ec));
+    asio::detail::throw_error(ec, "accept");
+    return peer;
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns On success, a socket object representing the newly accepted
+   * connection. On error, a socket object where is_open() is false.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(acceptor.accept(ec));
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  typename Protocol::socket accept(asio::error_code& ec)
+  {
+    return this->get_service().accept(this->get_implementation(), 0, 0, ec);
+  }
+
+  /// Start an asynchronous accept.
+  /**
+   * This function is used to asynchronously accept a new connection. The
+   * function call always returns immediately.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param handler The handler to be called when the accept operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   typename Protocol::socket peer // On success, the newly accepted socket.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void accept_handler(const asio::error_code& error,
+   *     asio::ip::tcp::socket peer)
+   * {
+   *   if (!error)
+   *   {
+   *     // Accept succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * acceptor.async_accept(accept_handler);
+   * @endcode
+   */
+  template <typename MoveAcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(MoveAcceptHandler,
+      void (asio::error_code, typename Protocol::socket))
+  async_accept(ASIO_MOVE_ARG(MoveAcceptHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a MoveAcceptHandler.
+    ASIO_MOVE_ACCEPT_HANDLER_CHECK(MoveAcceptHandler,
+        handler, typename Protocol::socket) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_accept(
+        this->get_implementation(), static_cast<asio::io_context*>(0),
+        static_cast<endpoint_type*>(0),
+        ASIO_MOVE_CAST(MoveAcceptHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<MoveAcceptHandler,
+      void (asio::error_code,
+        typename Protocol::socket)> init(handler);
+
+    this->get_service().async_accept(
+        this->get_implementation(), static_cast<asio::io_context*>(0),
+        static_cast<endpoint_type*>(0), init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param io_context The io_context object to be used for the newly accepted
+   * socket.
+   *
+   * @returns A socket object representing the newly accepted connection.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(acceptor.accept());
+   * @endcode
+   */
+  typename Protocol::socket accept(asio::io_context& io_context)
+  {
+    asio::error_code ec;
+    typename Protocol::socket peer(
+        this->get_service().accept(this->get_implementation(),
+          &io_context, static_cast<endpoint_type*>(0), ec));
+    asio::detail::throw_error(ec, "accept");
+    return peer;
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param io_context The io_context object to be used for the newly accepted
+   * socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns On success, a socket object representing the newly accepted
+   * connection. On error, a socket object where is_open() is false.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::socket socket(acceptor.accept(io_context2, ec));
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  typename Protocol::socket accept(
+      asio::io_context& io_context, asio::error_code& ec)
+  {
+    return this->get_service().accept(this->get_implementation(),
+        &io_context, static_cast<endpoint_type*>(0), ec);
+  }
+
+  /// Start an asynchronous accept.
+  /**
+   * This function is used to asynchronously accept a new connection. The
+   * function call always returns immediately.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param io_context The io_context object to be used for the newly accepted
+   * socket.
+   *
+   * @param handler The handler to be called when the accept operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   typename Protocol::socket peer // On success, the newly accepted socket.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void accept_handler(const asio::error_code& error,
+   *     asio::ip::tcp::socket peer)
+   * {
+   *   if (!error)
+   *   {
+   *     // Accept succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * acceptor.async_accept(io_context2, accept_handler);
+   * @endcode
+   */
+  template <typename MoveAcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(MoveAcceptHandler,
+      void (asio::error_code, typename Protocol::socket))
+  async_accept(asio::io_context& io_context,
+      ASIO_MOVE_ARG(MoveAcceptHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a MoveAcceptHandler.
+    ASIO_MOVE_ACCEPT_HANDLER_CHECK(MoveAcceptHandler,
+        handler, typename Protocol::socket) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_accept(this->get_implementation(),
+        &io_context, static_cast<endpoint_type*>(0),
+        ASIO_MOVE_CAST(MoveAcceptHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<MoveAcceptHandler,
+      void (asio::error_code,
+        typename Protocol::socket)> init(handler);
+
+    this->get_service().async_accept(this->get_implementation(),
+        &io_context, static_cast<endpoint_type*>(0), init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param peer_endpoint An endpoint object into which the endpoint of the
+   * remote peer will be written.
+   *
+   * @returns A socket object representing the newly accepted connection.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint;
+   * asio::ip::tcp::socket socket(acceptor.accept(endpoint));
+   * @endcode
+   */
+  typename Protocol::socket accept(endpoint_type& peer_endpoint)
+  {
+    asio::error_code ec;
+    typename Protocol::socket peer(
+        this->get_service().accept(this->get_implementation(),
+          static_cast<asio::io_context*>(0), &peer_endpoint, ec));
+    asio::detail::throw_error(ec, "accept");
+    return peer;
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param peer_endpoint An endpoint object into which the endpoint of the
+   * remote peer will be written.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns On success, a socket object representing the newly accepted
+   * connection. On error, a socket object where is_open() is false.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint;
+   * asio::ip::tcp::socket socket(acceptor.accept(endpoint, ec));
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  typename Protocol::socket accept(
+      endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    return this->get_service().accept(this->get_implementation(),
+        static_cast<asio::io_context*>(0), &peer_endpoint, ec);
+  }
+
+  /// Start an asynchronous accept.
+  /**
+   * This function is used to asynchronously accept a new connection. The
+   * function call always returns immediately.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param peer_endpoint An endpoint object into which the endpoint of the
+   * remote peer will be written. Ownership of the peer_endpoint object is
+   * retained by the caller, which must guarantee that it is valid until the
+   * handler is called.
+   *
+   * @param handler The handler to be called when the accept operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   typename Protocol::socket peer // On success, the newly accepted socket.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void accept_handler(const asio::error_code& error,
+   *     asio::ip::tcp::socket peer)
+   * {
+   *   if (!error)
+   *   {
+   *     // Accept succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint;
+   * acceptor.async_accept(endpoint, accept_handler);
+   * @endcode
+   */
+  template <typename MoveAcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(MoveAcceptHandler,
+      void (asio::error_code, typename Protocol::socket))
+  async_accept(endpoint_type& peer_endpoint,
+      ASIO_MOVE_ARG(MoveAcceptHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a MoveAcceptHandler.
+    ASIO_MOVE_ACCEPT_HANDLER_CHECK(MoveAcceptHandler,
+        handler, typename Protocol::socket) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_accept(this->get_implementation(),
+        static_cast<asio::io_context*>(0), &peer_endpoint,
+        ASIO_MOVE_CAST(MoveAcceptHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<MoveAcceptHandler,
+      void (asio::error_code,
+        typename Protocol::socket)> init(handler);
+
+    this->get_service().async_accept(this->get_implementation(),
+        static_cast<asio::io_context*>(0), &peer_endpoint,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param io_context The io_context object to be used for the newly accepted
+   * socket.
+   *
+   * @param peer_endpoint An endpoint object into which the endpoint of the
+   * remote peer will be written.
+   *
+   * @returns A socket object representing the newly accepted connection.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint;
+   * asio::ip::tcp::socket socket(
+   *     acceptor.accept(io_context2, endpoint));
+   * @endcode
+   */
+  typename Protocol::socket accept(
+      asio::io_context& io_context, endpoint_type& peer_endpoint)
+  {
+    asio::error_code ec;
+    typename Protocol::socket peer(
+        this->get_service().accept(this->get_implementation(),
+          &io_context, &peer_endpoint, ec));
+    asio::detail::throw_error(ec, "accept");
+    return peer;
+  }
+
+  /// Accept a new connection.
+  /**
+   * This function is used to accept a new connection from a peer. The function
+   * call will block until a new connection has been accepted successfully or
+   * an error occurs.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param io_context The io_context object to be used for the newly accepted
+   * socket.
+   *
+   * @param peer_endpoint An endpoint object into which the endpoint of the
+   * remote peer will be written.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns On success, a socket object representing the newly accepted
+   * connection. On error, a socket object where is_open() is false.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint;
+   * asio::ip::tcp::socket socket(
+   *     acceptor.accept(io_context2, endpoint, ec));
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * @endcode
+   */
+  typename Protocol::socket accept(asio::io_context& io_context,
+      endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    return this->get_service().accept(this->get_implementation(),
+        &io_context, &peer_endpoint, ec);
+  }
+
+  /// Start an asynchronous accept.
+  /**
+   * This function is used to asynchronously accept a new connection. The
+   * function call always returns immediately.
+   *
+   * This overload requires that the Protocol template parameter satisfy the
+   * AcceptableProtocol type requirements.
+   *
+   * @param io_context The io_context object to be used for the newly accepted
+   * socket.
+   *
+   * @param peer_endpoint An endpoint object into which the endpoint of the
+   * remote peer will be written. Ownership of the peer_endpoint object is
+   * retained by the caller, which must guarantee that it is valid until the
+   * handler is called.
+   *
+   * @param handler The handler to be called when the accept operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   typename Protocol::socket peer // On success, the newly accepted socket.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void accept_handler(const asio::error_code& error,
+   *     asio::ip::tcp::socket peer)
+   * {
+   *   if (!error)
+   *   {
+   *     // Accept succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::ip::tcp::acceptor acceptor(io_context);
+   * ...
+   * asio::ip::tcp::endpoint endpoint;
+   * acceptor.async_accept(io_context2, endpoint, accept_handler);
+   * @endcode
+   */
+  template <typename MoveAcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(MoveAcceptHandler,
+      void (asio::error_code, typename Protocol::socket))
+  async_accept(asio::io_context& io_context,
+      endpoint_type& peer_endpoint,
+      ASIO_MOVE_ARG(MoveAcceptHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a MoveAcceptHandler.
+    ASIO_MOVE_ACCEPT_HANDLER_CHECK(MoveAcceptHandler,
+        handler, typename Protocol::socket) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_accept(
+        this->get_implementation(), &io_context, &peer_endpoint,
+        ASIO_MOVE_CAST(MoveAcceptHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<MoveAcceptHandler,
+      void (asio::error_code,
+        typename Protocol::socket)> init(handler);
+
+    this->get_service().async_accept(this->get_implementation(),
+        &io_context, &peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# undef ASIO_SVC_T
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_BASIC_SOCKET_ACCEPTOR_HPP
diff --git a/subprojects/asio/include/asio/basic_socket_iostream.hpp b/subprojects/asio/include/asio/basic_socket_iostream.hpp
new file mode 100644
index 000000000..6681367fd
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_socket_iostream.hpp
@@ -0,0 +1,430 @@
+//
+// basic_socket_iostream.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_SOCKET_IOSTREAM_HPP
+#define ASIO_BASIC_SOCKET_IOSTREAM_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include <istream>
+#include <ostream>
+#include "asio/basic_socket_streambuf.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/stream_socket_service.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+# include "asio/detail/variadic_templates.hpp"
+
+// A macro that should expand to:
+//   template <typename T1, ..., typename Tn>
+//   explicit basic_socket_iostream(T1 x1, ..., Tn xn)
+//     : std::basic_iostream<char>(
+//         &this->detail::socket_iostream_base<
+//           Protocol ASIO_SVC_TARG, Clock,
+//           WaitTraits ASIO_SVC_TARG1>::streambuf_)
+//   {
+//     if (rdbuf()->connect(x1, ..., xn) == 0)
+//       this->setstate(std::ios_base::failbit);
+//   }
+// This macro should only persist within this file.
+
+# define ASIO_PRIVATE_CTR_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  explicit basic_socket_iostream(ASIO_VARIADIC_BYVAL_PARAMS(n)) \
+    : std::basic_iostream<char>( \
+        &this->detail::socket_iostream_base< \
+          Protocol ASIO_SVC_TARG, Clock, \
+          WaitTraits ASIO_SVC_TARG1>::streambuf_) \
+  { \
+    this->setf(std::ios_base::unitbuf); \
+    if (rdbuf()->connect(ASIO_VARIADIC_BYVAL_ARGS(n)) == 0) \
+      this->setstate(std::ios_base::failbit); \
+  } \
+  /**/
+
+// A macro that should expand to:
+//   template <typename T1, ..., typename Tn>
+//   void connect(T1 x1, ..., Tn xn)
+//   {
+//     if (rdbuf()->connect(x1, ..., xn) == 0)
+//       this->setstate(std::ios_base::failbit);
+//   }
+// This macro should only persist within this file.
+
+# define ASIO_PRIVATE_CONNECT_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  void connect(ASIO_VARIADIC_BYVAL_PARAMS(n)) \
+  { \
+    if (rdbuf()->connect(ASIO_VARIADIC_BYVAL_ARGS(n)) == 0) \
+      this->setstate(std::ios_base::failbit); \
+  } \
+  /**/
+
+#endif // !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// A separate base class is used to ensure that the streambuf is initialised
+// prior to the basic_socket_iostream's basic_iostream base class.
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Clock, typename WaitTraits ASIO_SVC_TPARAM1>
+class socket_iostream_base
+{
+protected:
+  socket_iostream_base()
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  socket_iostream_base(socket_iostream_base&& other)
+    : streambuf_(std::move(other.streambuf_))
+  {
+  }
+
+  socket_iostream_base(basic_stream_socket<Protocol> s)
+    : streambuf_(std::move(s))
+  {
+  }
+
+  socket_iostream_base& operator=(socket_iostream_base&& other)
+  {
+    streambuf_ = std::move(other.streambuf_);
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  basic_socket_streambuf<Protocol ASIO_SVC_TARG,
+    Clock, WaitTraits ASIO_SVC_TARG1> streambuf_;
+};
+
+} // namespace detail
+
+#if !defined(ASIO_BASIC_SOCKET_IOSTREAM_FWD_DECL)
+#define ASIO_BASIC_SOCKET_IOSTREAM_FWD_DECL
+
+// Forward declaration with defaulted arguments.
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= stream_socket_service<Protocol>),
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+    typename Clock = boost::posix_time::ptime,
+    typename WaitTraits = time_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF2(= deadline_timer_service<Clock, WaitTraits>)>
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+      // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+    typename Clock = chrono::steady_clock,
+    typename WaitTraits = wait_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF1(= steady_timer::service_type)>
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+class basic_socket_iostream;
+
+#endif // !defined(ASIO_BASIC_SOCKET_IOSTREAM_FWD_DECL)
+
+/// Iostream interface for a socket.
+#if defined(GENERATING_DOCUMENTATION)
+template <typename Protocol,
+    typename Clock = chrono::steady_clock,
+    typename WaitTraits = wait_traits<Clock> >
+#else // defined(GENERATING_DOCUMENTATION)
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Clock, typename WaitTraits ASIO_SVC_TPARAM1>
+#endif // defined(GENERATING_DOCUMENTATION)
+class basic_socket_iostream
+  : private detail::socket_iostream_base<Protocol
+        ASIO_SVC_TARG, Clock, WaitTraits ASIO_SVC_TARG1>,
+    public std::basic_iostream<char>
+{
+private:
+  // These typedefs are intended keep this class's implementation independent
+  // of whether it's using Boost.DateClock, Boost.Chrono or std::chrono.
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+  typedef WaitTraits traits_helper;
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+      // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+  typedef detail::chrono_time_traits<Clock, WaitTraits> traits_helper;
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+
+public:
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  /// The clock type.
+  typedef Clock clock_type;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// (Deprecated: Use time_point.) The time type.
+  typedef typename WaitTraits::time_type time_type;
+
+  /// The time type.
+  typedef typename WaitTraits::time_point time_point;
+
+  /// (Deprecated: Use duration.) The duration type.
+  typedef typename WaitTraits::duration_type duration_type;
+
+  /// The duration type.
+  typedef typename WaitTraits::duration duration;
+#else
+# if !defined(ASIO_NO_DEPRECATED)
+  typedef typename traits_helper::time_type time_type;
+  typedef typename traits_helper::duration_type duration_type;
+# endif // !defined(ASIO_NO_DEPRECATED)
+  typedef typename traits_helper::time_type time_point;
+  typedef typename traits_helper::duration_type duration;
+#endif
+
+  /// Construct a basic_socket_iostream without establishing a connection.
+  basic_socket_iostream()
+    : std::basic_iostream<char>(
+        &this->detail::socket_iostream_base<
+          Protocol ASIO_SVC_TARG, Clock,
+          WaitTraits ASIO_SVC_TARG1>::streambuf_)
+  {
+    this->setf(std::ios_base::unitbuf);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Construct a basic_socket_iostream from the supplied socket.
+  explicit basic_socket_iostream(basic_stream_socket<protocol_type> s)
+    : detail::socket_iostream_base<
+        Protocol ASIO_SVC_TARG, Clock,
+        WaitTraits ASIO_SVC_TARG1>(std::move(s)),
+      std::basic_iostream<char>(
+        &this->detail::socket_iostream_base<
+          Protocol ASIO_SVC_TARG, Clock,
+          WaitTraits ASIO_SVC_TARG1>::streambuf_)
+  {
+    this->setf(std::ios_base::unitbuf);
+  }
+
+#if defined(ASIO_HAS_STD_IOSTREAM_MOVE) \
+  || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_socket_iostream from another.
+  basic_socket_iostream(basic_socket_iostream&& other)
+    : detail::socket_iostream_base<
+        Protocol ASIO_SVC_TARG, Clock,
+        WaitTraits ASIO_SVC_TARG1>(std::move(other)),
+      std::basic_iostream<char>(std::move(other))
+  {
+    this->set_rdbuf(&this->detail::socket_iostream_base<
+          Protocol ASIO_SVC_TARG, Clock,
+          WaitTraits ASIO_SVC_TARG1>::streambuf_);
+  }
+
+  /// Move-assign a basic_socket_iostream from another.
+  basic_socket_iostream& operator=(basic_socket_iostream&& other)
+  {
+    std::basic_iostream<char>::operator=(std::move(other));
+    detail::socket_iostream_base<
+        Protocol ASIO_SVC_TARG, Clock,
+        WaitTraits ASIO_SVC_TARG1>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_STD_IOSTREAM_MOVE)
+       //   || defined(GENERATING_DOCUMENTATION)
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// Establish a connection to an endpoint corresponding to a resolver query.
+  /**
+   * This constructor automatically establishes a connection based on the
+   * supplied resolver query parameters. The arguments are used to construct
+   * a resolver query object.
+   */
+  template <typename T1, ..., typename TN>
+  explicit basic_socket_iostream(T1 t1, ..., TN tn);
+#elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
+  template <typename... T>
+  explicit basic_socket_iostream(T... x)
+    : std::basic_iostream<char>(
+        &this->detail::socket_iostream_base<
+          Protocol ASIO_SVC_TARG, Clock,
+          WaitTraits ASIO_SVC_TARG1>::streambuf_)
+  {
+    this->setf(std::ios_base::unitbuf);
+    if (rdbuf()->connect(x...) == 0)
+      this->setstate(std::ios_base::failbit);
+  }
+#else
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_CTR_DEF)
+#endif
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// Establish a connection to an endpoint corresponding to a resolver query.
+  /**
+   * This function automatically establishes a connection based on the supplied
+   * resolver query parameters. The arguments are used to construct a resolver
+   * query object.
+   */
+  template <typename T1, ..., typename TN>
+  void connect(T1 t1, ..., TN tn);
+#elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
+  template <typename... T>
+  void connect(T... x)
+  {
+    if (rdbuf()->connect(x...) == 0)
+      this->setstate(std::ios_base::failbit);
+  }
+#else
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_CONNECT_DEF)
+#endif
+
+  /// Close the connection.
+  void close()
+  {
+    if (rdbuf()->close() == 0)
+      this->setstate(std::ios_base::failbit);
+  }
+
+  /// Return a pointer to the underlying streambuf.
+  basic_socket_streambuf<Protocol ASIO_SVC_TARG,
+    Clock, WaitTraits ASIO_SVC_TARG1>* rdbuf() const
+  {
+    return const_cast<basic_socket_streambuf<Protocol ASIO_SVC_TARG,
+      Clock, WaitTraits ASIO_SVC_TARG1>*>(
+        &this->detail::socket_iostream_base<
+          Protocol ASIO_SVC_TARG, Clock,
+          WaitTraits ASIO_SVC_TARG1>::streambuf_);
+  }
+
+  /// Get a reference to the underlying socket.
+  basic_socket<Protocol ASIO_SVC_TARG>& socket()
+  {
+    return rdbuf()->socket();
+  }
+
+  /// Get the last error associated with the stream.
+  /**
+   * @return An \c error_code corresponding to the last error from the stream.
+   *
+   * @par Example
+   * To print the error associated with a failure to establish a connection:
+   * @code tcp::iostream s("www.boost.org", "http");
+   * if (!s)
+   * {
+   *   std::cout << "Error: " << s.error().message() << std::endl;
+   * } @endcode
+   */
+  const asio::error_code& error() const
+  {
+    return rdbuf()->error();
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use expiry().) Get the stream's expiry time as an absolute
+  /// time.
+  /**
+   * @return An absolute time value representing the stream's expiry time.
+   */
+  time_point expires_at() const
+  {
+    return rdbuf()->expires_at();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the stream's expiry time as an absolute time.
+  /**
+   * @return An absolute time value representing the stream's expiry time.
+   */
+  time_point expiry() const
+  {
+    return rdbuf()->expiry();
+  }
+
+  /// Set the stream's expiry time as an absolute time.
+  /**
+   * This function sets the expiry time associated with the stream. Stream
+   * operations performed after this time (where the operations cannot be
+   * completed using the internal buffers) will fail with the error
+   * asio::error::operation_aborted.
+   *
+   * @param expiry_time The expiry time to be used for the stream.
+   */
+  void expires_at(const time_point& expiry_time)
+  {
+    rdbuf()->expires_at(expiry_time);
+  }
+
+  /// Set the stream's expiry time relative to now.
+  /**
+   * This function sets the expiry time associated with the stream. Stream
+   * operations performed after this time (where the operations cannot be
+   * completed using the internal buffers) will fail with the error
+   * asio::error::operation_aborted.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   */
+  void expires_after(const duration& expiry_time)
+  {
+    rdbuf()->expires_after(expiry_time);
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use expiry().) Get the stream's expiry time relative to now.
+  /**
+   * @return A relative time value representing the stream's expiry time.
+   */
+  duration expires_from_now() const
+  {
+    return rdbuf()->expires_from_now();
+  }
+
+  /// (Deprecated: Use expires_after().) Set the stream's expiry time relative
+  /// to now.
+  /**
+   * This function sets the expiry time associated with the stream. Stream
+   * operations performed after this time (where the operations cannot be
+   * completed using the internal buffers) will fail with the error
+   * asio::error::operation_aborted.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   */
+  void expires_from_now(const duration& expiry_time)
+  {
+    rdbuf()->expires_from_now(expiry_time);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+private:
+  // Disallow copying and assignment.
+  basic_socket_iostream(const basic_socket_iostream&) ASIO_DELETED;
+  basic_socket_iostream& operator=(
+      const basic_socket_iostream&) ASIO_DELETED;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+# undef ASIO_PRIVATE_CTR_DEF
+# undef ASIO_PRIVATE_CONNECT_DEF
+#endif // !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_BASIC_SOCKET_IOSTREAM_HPP
diff --git a/subprojects/asio/include/asio/basic_socket_streambuf.hpp b/subprojects/asio/include/asio/basic_socket_streambuf.hpp
new file mode 100644
index 000000000..56a3637dc
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_socket_streambuf.hpp
@@ -0,0 +1,707 @@
+//
+// basic_socket_streambuf.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_SOCKET_STREAMBUF_HPP
+#define ASIO_BASIC_SOCKET_STREAMBUF_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include <streambuf>
+#include <vector>
+#include "asio/basic_socket.hpp"
+#include "asio/basic_stream_socket.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/stream_socket_service.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+# if defined(ASIO_ENABLE_OLD_SERVICES)
+#  include "asio/deadline_timer_service.hpp"
+# else // defined(ASIO_ENABLE_OLD_SERVICES)
+#  include "asio/detail/deadline_timer_service.hpp"
+# endif // defined(ASIO_ENABLE_OLD_SERVICES)
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+      // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+# include "asio/steady_timer.hpp"
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+
+#if !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+# include "asio/detail/variadic_templates.hpp"
+
+// A macro that should expand to:
+//   template <typename T1, ..., typename Tn>
+//   basic_socket_streambuf* connect(T1 x1, ..., Tn xn)
+//   {
+//     init_buffers();
+//     typedef typename Protocol::resolver resolver_type;
+//     resolver_type resolver(socket().get_executor().context());
+//     connect_to_endpoints(
+//         resolver.resolve(x1, ..., xn, ec_));
+//     return !ec_ ? this : 0;
+//   }
+// This macro should only persist within this file.
+
+# define ASIO_PRIVATE_CONNECT_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  basic_socket_streambuf* connect(ASIO_VARIADIC_BYVAL_PARAMS(n)) \
+  { \
+    init_buffers(); \
+    typedef typename Protocol::resolver resolver_type; \
+    resolver_type resolver(socket().get_executor().context()); \
+    connect_to_endpoints( \
+        resolver.resolve(ASIO_VARIADIC_BYVAL_ARGS(n), ec_)); \
+    return !ec_ ? this : 0; \
+  } \
+  /**/
+
+#endif // !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# define ASIO_SVC_T1 detail::deadline_timer_service<traits_helper>
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// A separate base class is used to ensure that the io_context member is
+// initialised prior to the basic_socket_streambuf's basic_socket base class.
+class socket_streambuf_io_context
+{
+protected:
+  socket_streambuf_io_context(io_context* ctx)
+    : default_io_context_(ctx)
+  {
+  }
+
+  shared_ptr<io_context> default_io_context_;
+};
+
+// A separate base class is used to ensure that the dynamically allocated
+// buffers are constructed prior to the basic_socket_streambuf's basic_socket
+// base class. This makes moving the socket is the last potentially throwing
+// step in the streambuf's move constructor, giving the constructor a strong
+// exception safety guarantee.
+class socket_streambuf_buffers
+{
+protected:
+  socket_streambuf_buffers()
+    : get_buffer_(buffer_size),
+      put_buffer_(buffer_size)
+  {
+  }
+
+  enum { buffer_size = 512 };
+  std::vector<char> get_buffer_;
+  std::vector<char> put_buffer_;
+};
+
+} // namespace detail
+
+#if !defined(ASIO_BASIC_SOCKET_STREAMBUF_FWD_DECL)
+#define ASIO_BASIC_SOCKET_STREAMBUF_FWD_DECL
+
+// Forward declaration with defaulted arguments.
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= stream_socket_service<Protocol>),
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+    typename Clock = boost::posix_time::ptime,
+    typename WaitTraits = time_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF2(= deadline_timer_service<Clock, WaitTraits>)>
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+      // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+    typename Clock = chrono::steady_clock,
+    typename WaitTraits = wait_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF1(= steady_timer::service_type)>
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+class basic_socket_streambuf;
+
+#endif // !defined(ASIO_BASIC_SOCKET_STREAMBUF_FWD_DECL)
+
+/// Iostream streambuf for a socket.
+#if defined(GENERATING_DOCUMENTATION)
+template <typename Protocol,
+    typename Clock = chrono::steady_clock,
+    typename WaitTraits = wait_traits<Clock> >
+#else // defined(GENERATING_DOCUMENTATION)
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Clock, typename WaitTraits ASIO_SVC_TPARAM1>
+#endif // defined(GENERATING_DOCUMENTATION)
+class basic_socket_streambuf
+  : public std::streambuf,
+    private detail::socket_streambuf_io_context,
+    private detail::socket_streambuf_buffers,
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+    private basic_socket<Protocol ASIO_SVC_TARG>
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+    public basic_socket<Protocol ASIO_SVC_TARG>
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+{
+private:
+  // These typedefs are intended keep this class's implementation independent
+  // of whether it's using Boost.DateClock, Boost.Chrono or std::chrono.
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+  typedef WaitTraits traits_helper;
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+      // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+  typedef detail::chrono_time_traits<Clock, WaitTraits> traits_helper;
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+
+public:
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  /// The clock type.
+  typedef Clock clock_type;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// (Deprecated: Use time_point.) The time type.
+  typedef typename WaitTraits::time_type time_type;
+
+  /// The time type.
+  typedef typename WaitTraits::time_point time_point;
+
+  /// (Deprecated: Use duration.) The duration type.
+  typedef typename WaitTraits::duration_type duration_type;
+
+  /// The duration type.
+  typedef typename WaitTraits::duration duration;
+#else
+# if !defined(ASIO_NO_DEPRECATED)
+  typedef typename traits_helper::time_type time_type;
+  typedef typename traits_helper::duration_type duration_type;
+# endif // !defined(ASIO_NO_DEPRECATED)
+  typedef typename traits_helper::time_type time_point;
+  typedef typename traits_helper::duration_type duration;
+#endif
+
+  /// Construct a basic_socket_streambuf without establishing a connection.
+  basic_socket_streambuf()
+    : detail::socket_streambuf_io_context(new io_context),
+      basic_socket<Protocol ASIO_SVC_TARG>(*default_io_context_),
+      expiry_time_(max_expiry_time())
+  {
+    init_buffers();
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Construct a basic_socket_streambuf from the supplied socket.
+  explicit basic_socket_streambuf(basic_stream_socket<protocol_type> s)
+    : detail::socket_streambuf_io_context(0),
+      basic_socket<Protocol ASIO_SVC_TARG>(std::move(s)),
+      expiry_time_(max_expiry_time())
+  {
+    init_buffers();
+  }
+
+  /// Move-construct a basic_socket_streambuf from another.
+  basic_socket_streambuf(basic_socket_streambuf&& other)
+    : detail::socket_streambuf_io_context(other),
+      basic_socket<Protocol ASIO_SVC_TARG>(std::move(other.socket())),
+      ec_(other.ec_),
+      expiry_time_(other.expiry_time_)
+  {
+    get_buffer_.swap(other.get_buffer_);
+    put_buffer_.swap(other.put_buffer_);
+    setg(other.eback(), other.gptr(), other.egptr());
+    setp(other.pptr(), other.epptr());
+    other.ec_ = asio::error_code();
+    other.expiry_time_ = max_expiry_time();
+    other.init_buffers();
+  }
+
+  /// Move-assign a basic_socket_streambuf from another.
+  basic_socket_streambuf& operator=(basic_socket_streambuf&& other)
+  {
+    this->close();
+    socket() = std::move(other.socket());
+    detail::socket_streambuf_io_context::operator=(other);
+    ec_ = other.ec_;
+    expiry_time_ = other.expiry_time_;
+    get_buffer_.swap(other.get_buffer_);
+    put_buffer_.swap(other.put_buffer_);
+    setg(other.eback(), other.gptr(), other.egptr());
+    setp(other.pptr(), other.epptr());
+    other.ec_ = asio::error_code();
+    other.expiry_time_ = max_expiry_time();
+    other.put_buffer_.resize(buffer_size);
+    other.init_buffers();
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destructor flushes buffered data.
+  virtual ~basic_socket_streambuf()
+  {
+    if (pptr() != pbase())
+      overflow(traits_type::eof());
+  }
+
+  /// Establish a connection.
+  /**
+   * This function establishes a connection to the specified endpoint.
+   *
+   * @return \c this if a connection was successfully established, a null
+   * pointer otherwise.
+   */
+  basic_socket_streambuf* connect(const endpoint_type& endpoint)
+  {
+    init_buffers();
+    ec_ = asio::error_code();
+    this->connect_to_endpoints(&endpoint, &endpoint + 1);
+    return !ec_ ? this : 0;
+  }
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// Establish a connection.
+  /**
+   * This function automatically establishes a connection based on the supplied
+   * resolver query parameters. The arguments are used to construct a resolver
+   * query object.
+   *
+   * @return \c this if a connection was successfully established, a null
+   * pointer otherwise.
+   */
+  template <typename T1, ..., typename TN>
+  basic_socket_streambuf* connect(T1 t1, ..., TN tn);
+#elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
+  template <typename... T>
+  basic_socket_streambuf* connect(T... x)
+  {
+    init_buffers();
+    typedef typename Protocol::resolver resolver_type;
+    resolver_type resolver(socket().get_executor().context());
+    connect_to_endpoints(resolver.resolve(x..., ec_));
+    return !ec_ ? this : 0;
+  }
+#else
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_CONNECT_DEF)
+#endif
+
+  /// Close the connection.
+  /**
+   * @return \c this if a connection was successfully established, a null
+   * pointer otherwise.
+   */
+  basic_socket_streambuf* close()
+  {
+    sync();
+    socket().close(ec_);
+    if (!ec_)
+      init_buffers();
+    return !ec_ ? this : 0;
+  }
+
+  /// Get a reference to the underlying socket.
+  basic_socket<Protocol ASIO_SVC_TARG>& socket()
+  {
+    return *this;
+  }
+
+  /// Get the last error associated with the stream buffer.
+  /**
+   * @return An \c error_code corresponding to the last error from the stream
+   * buffer.
+   */
+  const asio::error_code& error() const
+  {
+    return ec_;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use error().) Get the last error associated with the stream
+  /// buffer.
+  /**
+   * @return An \c error_code corresponding to the last error from the stream
+   * buffer.
+   */
+  const asio::error_code& puberror() const
+  {
+    return error();
+  }
+
+  /// (Deprecated: Use expiry().) Get the stream buffer's expiry time as an
+  /// absolute time.
+  /**
+   * @return An absolute time value representing the stream buffer's expiry
+   * time.
+   */
+  time_point expires_at() const
+  {
+    return expiry_time_;
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the stream buffer's expiry time as an absolute time.
+  /**
+   * @return An absolute time value representing the stream buffer's expiry
+   * time.
+   */
+  time_point expiry() const
+  {
+    return expiry_time_;
+  }
+
+  /// Set the stream buffer's expiry time as an absolute time.
+  /**
+   * This function sets the expiry time associated with the stream. Stream
+   * operations performed after this time (where the operations cannot be
+   * completed using the internal buffers) will fail with the error
+   * asio::error::operation_aborted.
+   *
+   * @param expiry_time The expiry time to be used for the stream.
+   */
+  void expires_at(const time_point& expiry_time)
+  {
+    expiry_time_ = expiry_time;
+  }
+
+  /// Set the stream buffer's expiry time relative to now.
+  /**
+   * This function sets the expiry time associated with the stream. Stream
+   * operations performed after this time (where the operations cannot be
+   * completed using the internal buffers) will fail with the error
+   * asio::error::operation_aborted.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   */
+  void expires_after(const duration& expiry_time)
+  {
+    expiry_time_ = traits_helper::add(traits_helper::now(), expiry_time);
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use expiry().) Get the stream buffer's expiry time relative
+  /// to now.
+  /**
+   * @return A relative time value representing the stream buffer's expiry time.
+   */
+  duration expires_from_now() const
+  {
+    return traits_helper::subtract(expires_at(), traits_helper::now());
+  }
+
+  /// (Deprecated: Use expires_after().) Set the stream buffer's expiry time
+  /// relative to now.
+  /**
+   * This function sets the expiry time associated with the stream. Stream
+   * operations performed after this time (where the operations cannot be
+   * completed using the internal buffers) will fail with the error
+   * asio::error::operation_aborted.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   */
+  void expires_from_now(const duration& expiry_time)
+  {
+    expiry_time_ = traits_helper::add(traits_helper::now(), expiry_time);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+protected:
+  int_type underflow()
+  {
+#if defined(ASIO_WINDOWS_RUNTIME)
+    ec_ = asio::error::operation_not_supported;
+    return traits_type::eof();
+#else // defined(ASIO_WINDOWS_RUNTIME)
+    if (gptr() != egptr())
+      return traits_type::eof();
+
+    for (;;)
+    {
+      // Check if we are past the expiry time.
+      if (traits_helper::less_than(expiry_time_, traits_helper::now()))
+      {
+        ec_ = asio::error::timed_out;
+        return traits_type::eof();
+      }
+
+      // Try to complete the operation without blocking.
+      if (!socket().native_non_blocking())
+        socket().native_non_blocking(true, ec_);
+      detail::buffer_sequence_adapter<mutable_buffer, mutable_buffer>
+        bufs(asio::buffer(get_buffer_) + putback_max);
+      detail::signed_size_type bytes = detail::socket_ops::recv(
+          socket().native_handle(), bufs.buffers(), bufs.count(), 0, ec_);
+
+      // Check if operation succeeded.
+      if (bytes > 0)
+      {
+        setg(&get_buffer_[0], &get_buffer_[0] + putback_max,
+            &get_buffer_[0] + putback_max + bytes);
+        return traits_type::to_int_type(*gptr());
+      }
+
+      // Check for EOF.
+      if (bytes == 0)
+      {
+        ec_ = asio::error::eof;
+        return traits_type::eof();
+      }
+
+      // Operation failed.
+      if (ec_ != asio::error::would_block
+          && ec_ != asio::error::try_again)
+        return traits_type::eof();
+
+      // Wait for socket to become ready.
+      if (detail::socket_ops::poll_read(
+            socket().native_handle(), 0, timeout(), ec_) < 0)
+        return traits_type::eof();
+    }
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+  }
+
+  int_type overflow(int_type c)
+  {
+#if defined(ASIO_WINDOWS_RUNTIME)
+    ec_ = asio::error::operation_not_supported;
+    return traits_type::eof();
+#else // defined(ASIO_WINDOWS_RUNTIME)
+    char_type ch = traits_type::to_char_type(c);
+
+    // Determine what needs to be sent.
+    const_buffer output_buffer;
+    if (put_buffer_.empty())
+    {
+      if (traits_type::eq_int_type(c, traits_type::eof()))
+        return traits_type::not_eof(c); // Nothing to do.
+      output_buffer = asio::buffer(&ch, sizeof(char_type));
+    }
+    else
+    {
+      output_buffer = asio::buffer(pbase(),
+          (pptr() - pbase()) * sizeof(char_type));
+    }
+
+    while (output_buffer.size() > 0)
+    {
+      // Check if we are past the expiry time.
+      if (traits_helper::less_than(expiry_time_, traits_helper::now()))
+      {
+        ec_ = asio::error::timed_out;
+        return traits_type::eof();
+      }
+
+      // Try to complete the operation without blocking.
+      if (!socket().native_non_blocking())
+        socket().native_non_blocking(true, ec_);
+      detail::buffer_sequence_adapter<
+        const_buffer, const_buffer> bufs(output_buffer);
+      detail::signed_size_type bytes = detail::socket_ops::send(
+          socket().native_handle(), bufs.buffers(), bufs.count(), 0, ec_);
+
+      // Check if operation succeeded.
+      if (bytes > 0)
+      {
+        output_buffer += static_cast<std::size_t>(bytes);
+        continue;
+      }
+
+      // Operation failed.
+      if (ec_ != asio::error::would_block
+          && ec_ != asio::error::try_again)
+        return traits_type::eof();
+
+      // Wait for socket to become ready.
+      if (detail::socket_ops::poll_write(
+            socket().native_handle(), 0, timeout(), ec_) < 0)
+        return traits_type::eof();
+    }
+
+    if (!put_buffer_.empty())
+    {
+      setp(&put_buffer_[0], &put_buffer_[0] + put_buffer_.size());
+
+      // If the new character is eof then our work here is done.
+      if (traits_type::eq_int_type(c, traits_type::eof()))
+        return traits_type::not_eof(c);
+
+      // Add the new character to the output buffer.
+      *pptr() = ch;
+      pbump(1);
+    }
+
+    return c;
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+  }
+
+  int sync()
+  {
+    return overflow(traits_type::eof());
+  }
+
+  std::streambuf* setbuf(char_type* s, std::streamsize n)
+  {
+    if (pptr() == pbase() && s == 0 && n == 0)
+    {
+      put_buffer_.clear();
+      setp(0, 0);
+      sync();
+      return this;
+    }
+
+    return 0;
+  }
+
+private:
+  // Disallow copying and assignment.
+  basic_socket_streambuf(const basic_socket_streambuf&) ASIO_DELETED;
+  basic_socket_streambuf& operator=(
+      const basic_socket_streambuf&) ASIO_DELETED;
+
+  void init_buffers()
+  {
+    setg(&get_buffer_[0],
+        &get_buffer_[0] + putback_max,
+        &get_buffer_[0] + putback_max);
+
+    if (put_buffer_.empty())
+      setp(0, 0);
+    else
+      setp(&put_buffer_[0], &put_buffer_[0] + put_buffer_.size());
+  }
+
+  int timeout() const
+  {
+    int64_t msec = traits_helper::to_posix_duration(
+        traits_helper::subtract(expiry_time_,
+          traits_helper::now())).total_milliseconds();
+    if (msec > (std::numeric_limits<int>::max)())
+      msec = (std::numeric_limits<int>::max)();
+    else if (msec < 0)
+      msec = 0;
+    return static_cast<int>(msec);
+  }
+
+  template <typename EndpointSequence>
+  void connect_to_endpoints(const EndpointSequence& endpoints)
+  {
+    this->connect_to_endpoints(endpoints.begin(), endpoints.end());
+  }
+
+  template <typename EndpointIterator>
+  void connect_to_endpoints(EndpointIterator begin, EndpointIterator end)
+  {
+#if defined(ASIO_WINDOWS_RUNTIME)
+    ec_ = asio::error::operation_not_supported;
+#else // defined(ASIO_WINDOWS_RUNTIME)
+    if (ec_)
+      return;
+
+    ec_ = asio::error::not_found;
+    for (EndpointIterator i = begin; i != end; ++i)
+    {
+      // Check if we are past the expiry time.
+      if (traits_helper::less_than(expiry_time_, traits_helper::now()))
+      {
+        ec_ = asio::error::timed_out;
+        return;
+      }
+
+      // Close and reopen the socket.
+      typename Protocol::endpoint ep(*i);
+      socket().close(ec_);
+      socket().open(ep.protocol(), ec_);
+      if (ec_)
+        continue;
+
+      // Try to complete the operation without blocking.
+      if (!socket().native_non_blocking())
+        socket().native_non_blocking(true, ec_);
+      detail::socket_ops::connect(socket().native_handle(),
+          ep.data(), ep.size(), ec_);
+
+      // Check if operation succeeded.
+      if (!ec_)
+        return;
+
+      // Operation failed.
+      if (ec_ != asio::error::in_progress
+          && ec_ != asio::error::would_block)
+        continue;
+
+      // Wait for socket to become ready.
+      if (detail::socket_ops::poll_connect(
+            socket().native_handle(), timeout(), ec_) < 0)
+        continue;
+
+      // Get the error code from the connect operation.
+      int connect_error = 0;
+      size_t connect_error_len = sizeof(connect_error);
+      if (detail::socket_ops::getsockopt(socket().native_handle(), 0,
+            SOL_SOCKET, SO_ERROR, &connect_error, &connect_error_len, ec_)
+          == detail::socket_error_retval)
+        return;
+
+      // Check the result of the connect operation.
+      ec_ = asio::error_code(connect_error,
+          asio::error::get_system_category());
+      if (!ec_)
+        return;
+    }
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+  }
+
+  // Helper function to get the maximum expiry time.
+  static time_point max_expiry_time()
+  {
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+    return boost::posix_time::pos_infin;
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+      // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+    return (time_point::max)();
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // && defined(ASIO_USE_BOOST_DATE_TIME_FOR_SOCKET_IOSTREAM)
+  }
+
+  enum { putback_max = 8 };
+  asio::error_code ec_;
+  time_point expiry_time_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# undef ASIO_SVC_T1
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+# undef ASIO_PRIVATE_CONNECT_DEF
+#endif // !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_BASIC_SOCKET_STREAMBUF_HPP
diff --git a/subprojects/asio/include/asio/basic_stream_socket.hpp b/subprojects/asio/include/asio/basic_stream_socket.hpp
new file mode 100644
index 000000000..eea886274
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_stream_socket.hpp
@@ -0,0 +1,921 @@
+//
+// basic_stream_socket.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_STREAM_SOCKET_HPP
+#define ASIO_BASIC_STREAM_SOCKET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/basic_socket.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/stream_socket_service.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides stream-oriented socket functionality.
+/**
+ * The basic_stream_socket class template provides asynchronous and blocking
+ * stream-oriented socket functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= stream_socket_service<Protocol>)>
+class basic_stream_socket
+  : public basic_socket<Protocol ASIO_SVC_TARG>
+{
+public:
+  /// The native representation of a socket.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename basic_socket<
+    Protocol ASIO_SVC_TARG>::native_handle_type native_handle_type;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  /// Construct a basic_stream_socket without opening it.
+  /**
+   * This constructor creates a stream socket without opening it. The socket
+   * needs to be opened and then connected or accepted before data can be sent
+   * or received on it.
+   *
+   * @param io_context The io_context object that the stream socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   */
+  explicit basic_stream_socket(asio::io_context& io_context)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context)
+  {
+  }
+
+  /// Construct and open a basic_stream_socket.
+  /**
+   * This constructor creates and opens a stream socket. The socket needs to be
+   * connected or accepted before data can be sent or received on it.
+   *
+   * @param io_context The io_context object that the stream socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_stream_socket(asio::io_context& io_context,
+      const protocol_type& protocol)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, protocol)
+  {
+  }
+
+  /// Construct a basic_stream_socket, opening it and binding it to the given
+  /// local endpoint.
+  /**
+   * This constructor creates a stream socket and automatically opens it bound
+   * to the specified endpoint on the local machine. The protocol used is the
+   * protocol associated with the given endpoint.
+   *
+   * @param io_context The io_context object that the stream socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   *
+   * @param endpoint An endpoint on the local machine to which the stream
+   * socket will be bound.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_stream_socket(asio::io_context& io_context,
+      const endpoint_type& endpoint)
+    : basic_socket<Protocol ASIO_SVC_TARG>(io_context, endpoint)
+  {
+  }
+
+  /// Construct a basic_stream_socket on an existing native socket.
+  /**
+   * This constructor creates a stream socket object to hold an existing native
+   * socket.
+   *
+   * @param io_context The io_context object that the stream socket will use to
+   * dispatch handlers for any asynchronous operations performed on the socket.
+   *
+   * @param protocol An object specifying protocol parameters to be used.
+   *
+   * @param native_socket The new underlying socket implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_stream_socket(asio::io_context& io_context,
+      const protocol_type& protocol, const native_handle_type& native_socket)
+    : basic_socket<Protocol ASIO_SVC_TARG>(
+        io_context, protocol, native_socket)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_stream_socket from another.
+  /**
+   * This constructor moves a stream socket from one object to another.
+   *
+   * @param other The other basic_stream_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_socket(io_context&) constructor.
+   */
+  basic_stream_socket(basic_stream_socket&& other)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_stream_socket from another.
+  /**
+   * This assignment operator moves a stream socket from one object to another.
+   *
+   * @param other The other basic_stream_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_socket(io_context&) constructor.
+   */
+  basic_stream_socket& operator=(basic_stream_socket&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+
+  /// Move-construct a basic_stream_socket from a socket of another protocol
+  /// type.
+  /**
+   * This constructor moves a stream socket from one object to another.
+   *
+   * @param other The other basic_stream_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  basic_stream_socket(
+      basic_stream_socket<Protocol1 ASIO_SVC_TARG1>&& other,
+      typename enable_if<is_convertible<Protocol1, Protocol>::value>::type* = 0)
+    : basic_socket<Protocol ASIO_SVC_TARG>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_stream_socket from a socket of another protocol type.
+  /**
+   * This assignment operator moves a stream socket from one object to another.
+   *
+   * @param other The other basic_stream_socket object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_socket(io_context&) constructor.
+   */
+  template <typename Protocol1 ASIO_SVC_TPARAM1>
+  typename enable_if<is_convertible<Protocol1, Protocol>::value,
+      basic_stream_socket>::type& operator=(
+        basic_stream_socket<Protocol1 ASIO_SVC_TARG1>&& other)
+  {
+    basic_socket<Protocol ASIO_SVC_TARG>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the socket.
+  /**
+   * This function destroys the socket, cancelling any outstanding asynchronous
+   * operations associated with the socket as if by calling @c cancel.
+   */
+  ~basic_stream_socket()
+  {
+  }
+
+  /// Send some data on the socket.
+  /**
+   * This function is used to send data on the stream socket. The function
+   * call will block until one or more bytes of the data has been sent
+   * successfully, or an until error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The send operation may not transmit all of the data to the peer.
+   * Consider using the @ref write function if you need to ensure that all data
+   * is written before the blocking operation completes.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.send(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "send");
+    return s;
+  }
+
+  /// Send some data on the socket.
+  /**
+   * This function is used to send data on the stream socket. The function
+   * call will block until one or more bytes of the data has been sent
+   * successfully, or an until error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @returns The number of bytes sent.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The send operation may not transmit all of the data to the peer.
+   * Consider using the @ref write function if you need to ensure that all data
+   * is written before the blocking operation completes.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.send(asio::buffer(data, size), 0);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+    asio::detail::throw_error(ec, "send");
+    return s;
+  }
+
+  /// Send some data on the socket.
+  /**
+   * This function is used to send data on the stream socket. The function
+   * call will block until one or more bytes of the data has been sent
+   * successfully, or an until error occurs.
+   *
+   * @param buffers One or more data buffers to be sent on the socket.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes sent. Returns 0 if an error occurred.
+   *
+   * @note The send operation may not transmit all of the data to the peer.
+   * Consider using the @ref write function if you need to ensure that all data
+   * is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return this->get_service().send(
+        this->get_implementation(), buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  /**
+   * This function is used to asynchronously send data on the stream socket.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent on the socket. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * memory blocks is retained by the caller, which must guarantee that they
+   * remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The send operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.async_send(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(
+        this->get_implementation(), buffers, 0,
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(
+        this->get_implementation(), buffers, 0,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous send.
+  /**
+   * This function is used to asynchronously send data on the stream socket.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be sent on the socket. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * memory blocks is retained by the caller, which must guarantee that they
+   * remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the send call is to be made.
+   *
+   * @param handler The handler to be called when the send operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes sent.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The send operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To send a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.async_send(asio::buffer(data, size), 0, handler);
+   * @endcode
+   * See the @ref buffer documentation for information on sending multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(
+        this->get_implementation(), buffers, flags,
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(
+        this->get_implementation(), buffers, flags,
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Receive some data on the socket.
+  /**
+   * This function is used to receive data on the stream socket. The function
+   * call will block until one or more bytes of data has been received
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The receive operation may not receive all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that the
+   * requested amount of data is read before the blocking operation completes.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.receive(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on the socket.
+  /**
+   * This function is used to receive data on the stream socket. The function
+   * call will block until one or more bytes of data has been received
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @returns The number of bytes received.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The receive operation may not receive all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that the
+   * requested amount of data is read before the blocking operation completes.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.receive(asio::buffer(data, size), 0);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, flags, ec);
+    asio::detail::throw_error(ec, "receive");
+    return s;
+  }
+
+  /// Receive some data on a connected socket.
+  /**
+   * This function is used to receive data on the stream socket. The function
+   * call will block until one or more bytes of data has been received
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes received. Returns 0 if an error occurred.
+   *
+   * @note The receive operation may not receive all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that the
+   * requested amount of data is read before the blocking operation completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return this->get_service().receive(
+        this->get_implementation(), buffers, flags, ec);
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive data from the stream
+   * socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The receive operation may not receive all of the requested number of
+   * bytes. Consider using the @ref async_read function if you need to ensure
+   * that the requested amount of data is received before the asynchronous
+   * operation completes.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.async_receive(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Start an asynchronous receive.
+  /**
+   * This function is used to asynchronously receive data from the stream
+   * socket. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be received.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param flags Flags specifying how the receive call is to be made.
+   *
+   * @param handler The handler to be called when the receive operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes received.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The receive operation may not receive all of the requested number of
+   * bytes. Consider using the @ref async_read function if you need to ensure
+   * that the requested amount of data is received before the asynchronous
+   * operation completes.
+   *
+   * @par Example
+   * To receive into a single data buffer use the @ref buffer function as
+   * follows:
+   * @code
+   * socket.async_receive(asio::buffer(data, size), 0, handler);
+   * @endcode
+   * See the @ref buffer documentation for information on receiving into
+   * multiple buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(const MutableBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(this->get_implementation(),
+        buffers, flags, ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive(this->get_implementation(),
+        buffers, flags, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Write some data to the socket.
+  /**
+   * This function is used to write data to the stream socket. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the socket.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.write_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().send(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return s;
+  }
+
+  /// Write some data to the socket.
+  /**
+   * This function is used to write data to the stream socket. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the socket.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().send(this->get_implementation(), buffers, 0, ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write data to the stream socket.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be written to the socket.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.async_write_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_send(this->get_implementation(),
+        buffers, 0, ASIO_MOVE_CAST(WriteHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_send(this->get_implementation(),
+        buffers, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Read some data from the socket.
+  /**
+   * This function is used to read data from the stream socket. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.read_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().receive(
+        this->get_implementation(), buffers, 0, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return s;
+  }
+
+  /// Read some data from the socket.
+  /**
+   * This function is used to read data from the stream socket. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().receive(
+        this->get_implementation(), buffers, 0, ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read data from the stream socket.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read function if you need to ensure that the
+   * requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * socket.async_read_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, ASIO_MOVE_CAST(ReadHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_receive(this->get_implementation(),
+        buffers, 0, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BASIC_STREAM_SOCKET_HPP
diff --git a/subprojects/asio/include/asio/basic_streambuf.hpp b/subprojects/asio/include/asio/basic_streambuf.hpp
new file mode 100644
index 000000000..14f85d22f
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_streambuf.hpp
@@ -0,0 +1,452 @@
+//
+// basic_streambuf.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_STREAMBUF_HPP
+#define ASIO_BASIC_STREAMBUF_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include <algorithm>
+#include <cstring>
+#include <stdexcept>
+#include <streambuf>
+#include <vector>
+#include "asio/basic_streambuf_fwd.hpp"
+#include "asio/buffer.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/throw_exception.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Automatically resizable buffer class based on std::streambuf.
+/**
+ * The @c basic_streambuf class is derived from @c std::streambuf to associate
+ * the streambuf's input and output sequences with one or more character
+ * arrays. These character arrays are internal to the @c basic_streambuf
+ * object, but direct access to the array elements is provided to permit them
+ * to be used efficiently with I/O operations. Characters written to the output
+ * sequence of a @c basic_streambuf object are appended to the input sequence
+ * of the same object.
+ *
+ * The @c basic_streambuf class's public interface is intended to permit the
+ * following implementation strategies:
+ *
+ * @li A single contiguous character array, which is reallocated as necessary
+ * to accommodate changes in the size of the character sequence. This is the
+ * implementation approach currently used in Asio.
+ *
+ * @li A sequence of one or more character arrays, where each array is of the
+ * same size. Additional character array objects are appended to the sequence
+ * to accommodate changes in the size of the character sequence.
+ *
+ * @li A sequence of one or more character arrays of varying sizes. Additional
+ * character array objects are appended to the sequence to accommodate changes
+ * in the size of the character sequence.
+ *
+ * The constructor for basic_streambuf accepts a @c size_t argument specifying
+ * the maximum of the sum of the sizes of the input sequence and output
+ * sequence. During the lifetime of the @c basic_streambuf object, the following
+ * invariant holds:
+ * @code size() <= max_size()@endcode
+ * Any member function that would, if successful, cause the invariant to be
+ * violated shall throw an exception of class @c std::length_error.
+ *
+ * The constructor for @c basic_streambuf takes an Allocator argument. A copy
+ * of this argument is used for any memory allocation performed, by the
+ * constructor and by all member functions, during the lifetime of each @c
+ * basic_streambuf object.
+ *
+ * @par Examples
+ * Writing directly from an streambuf to a socket:
+ * @code
+ * asio::streambuf b;
+ * std::ostream os(&b);
+ * os << "Hello, World!\n";
+ *
+ * // try sending some data in input sequence
+ * size_t n = sock.send(b.data());
+ *
+ * b.consume(n); // sent data is removed from input sequence
+ * @endcode
+ *
+ * Reading from a socket directly into a streambuf:
+ * @code
+ * asio::streambuf b;
+ *
+ * // reserve 512 bytes in output sequence
+ * asio::streambuf::mutable_buffers_type bufs = b.prepare(512);
+ *
+ * size_t n = sock.receive(bufs);
+ *
+ * // received data is "committed" from output sequence to input sequence
+ * b.commit(n);
+ *
+ * std::istream is(&b);
+ * std::string s;
+ * is >> s;
+ * @endcode
+ */
+#if defined(GENERATING_DOCUMENTATION)
+template <typename Allocator = std::allocator<char> >
+#else
+template <typename Allocator>
+#endif
+class basic_streambuf
+  : public std::streambuf,
+    private noncopyable
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The type used to represent the input sequence as a list of buffers.
+  typedef implementation_defined const_buffers_type;
+
+  /// The type used to represent the output sequence as a list of buffers.
+  typedef implementation_defined mutable_buffers_type;
+#else
+  typedef ASIO_CONST_BUFFER const_buffers_type;
+  typedef ASIO_MUTABLE_BUFFER mutable_buffers_type;
+#endif
+
+  /// Construct a basic_streambuf object.
+  /**
+   * Constructs a streambuf with the specified maximum size. The initial size
+   * of the streambuf's input sequence is 0.
+   */
+  explicit basic_streambuf(
+      std::size_t maximum_size = (std::numeric_limits<std::size_t>::max)(),
+      const Allocator& allocator = Allocator())
+    : max_size_(maximum_size),
+      buffer_(allocator)
+  {
+    std::size_t pend = (std::min<std::size_t>)(max_size_, buffer_delta);
+    buffer_.resize((std::max<std::size_t>)(pend, 1));
+    setg(&buffer_[0], &buffer_[0], &buffer_[0]);
+    setp(&buffer_[0], &buffer_[0] + pend);
+  }
+
+  /// Get the size of the input sequence.
+  /**
+   * @returns The size of the input sequence. The value is equal to that
+   * calculated for @c s in the following code:
+   * @code
+   * size_t s = 0;
+   * const_buffers_type bufs = data();
+   * const_buffers_type::const_iterator i = bufs.begin();
+   * while (i != bufs.end())
+   * {
+   *   const_buffer buf(*i++);
+   *   s += buf.size();
+   * }
+   * @endcode
+   */
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return pptr() - gptr();
+  }
+
+  /// Get the maximum size of the basic_streambuf.
+  /**
+   * @returns The allowed maximum of the sum of the sizes of the input sequence
+   * and output sequence.
+   */
+  std::size_t max_size() const ASIO_NOEXCEPT
+  {
+    return max_size_;
+  }
+
+  /// Get the current capacity of the basic_streambuf.
+  /**
+   * @returns The current total capacity of the streambuf, i.e. for both the
+   * input sequence and output sequence.
+   */
+  std::size_t capacity() const ASIO_NOEXCEPT
+  {
+    return buffer_.capacity();
+  }
+
+  /// Get a list of buffers that represents the input sequence.
+  /**
+   * @returns An object of type @c const_buffers_type that satisfies
+   * ConstBufferSequence requirements, representing all character arrays in the
+   * input sequence.
+   *
+   * @note The returned object is invalidated by any @c basic_streambuf member
+   * function that modifies the input sequence or output sequence.
+   */
+  const_buffers_type data() const ASIO_NOEXCEPT
+  {
+    return asio::buffer(asio::const_buffer(gptr(),
+          (pptr() - gptr()) * sizeof(char_type)));
+  }
+
+  /// Get a list of buffers that represents the output sequence, with the given
+  /// size.
+  /**
+   * Ensures that the output sequence can accommodate @c n characters,
+   * reallocating character array objects as necessary.
+   *
+   * @returns An object of type @c mutable_buffers_type that satisfies
+   * MutableBufferSequence requirements, representing character array objects
+   * at the start of the output sequence such that the sum of the buffer sizes
+   * is @c n.
+   *
+   * @throws std::length_error If <tt>size() + n > max_size()</tt>.
+   *
+   * @note The returned object is invalidated by any @c basic_streambuf member
+   * function that modifies the input sequence or output sequence.
+   */
+  mutable_buffers_type prepare(std::size_t n)
+  {
+    reserve(n);
+    return asio::buffer(asio::mutable_buffer(
+          pptr(), n * sizeof(char_type)));
+  }
+
+  /// Move characters from the output sequence to the input sequence.
+  /**
+   * Appends @c n characters from the start of the output sequence to the input
+   * sequence. The beginning of the output sequence is advanced by @c n
+   * characters.
+   *
+   * Requires a preceding call <tt>prepare(x)</tt> where <tt>x >= n</tt>, and
+   * no intervening operations that modify the input or output sequence.
+   *
+   * @note If @c n is greater than the size of the output sequence, the entire
+   * output sequence is moved to the input sequence and no error is issued.
+   */
+  void commit(std::size_t n)
+  {
+    n = std::min<std::size_t>(n, epptr() - pptr());
+    pbump(static_cast<int>(n));
+    setg(eback(), gptr(), pptr());
+  }
+
+  /// Remove characters from the input sequence.
+  /**
+   * Removes @c n characters from the beginning of the input sequence.
+   *
+   * @note If @c n is greater than the size of the input sequence, the entire
+   * input sequence is consumed and no error is issued.
+   */
+  void consume(std::size_t n)
+  {
+    if (egptr() < pptr())
+      setg(&buffer_[0], gptr(), pptr());
+    if (gptr() + n > pptr())
+      n = pptr() - gptr();
+    gbump(static_cast<int>(n));
+  }
+
+protected:
+  enum { buffer_delta = 128 };
+
+  /// Override std::streambuf behaviour.
+  /**
+   * Behaves according to the specification of @c std::streambuf::underflow().
+   */
+  int_type underflow()
+  {
+    if (gptr() < pptr())
+    {
+      setg(&buffer_[0], gptr(), pptr());
+      return traits_type::to_int_type(*gptr());
+    }
+    else
+    {
+      return traits_type::eof();
+    }
+  }
+
+  /// Override std::streambuf behaviour.
+  /**
+   * Behaves according to the specification of @c std::streambuf::overflow(),
+   * with the specialisation that @c std::length_error is thrown if appending
+   * the character to the input sequence would require the condition
+   * <tt>size() > max_size()</tt> to be true.
+   */
+  int_type overflow(int_type c)
+  {
+    if (!traits_type::eq_int_type(c, traits_type::eof()))
+    {
+      if (pptr() == epptr())
+      {
+        std::size_t buffer_size = pptr() - gptr();
+        if (buffer_size < max_size_ && max_size_ - buffer_size < buffer_delta)
+        {
+          reserve(max_size_ - buffer_size);
+        }
+        else
+        {
+          reserve(buffer_delta);
+        }
+      }
+
+      *pptr() = traits_type::to_char_type(c);
+      pbump(1);
+      return c;
+    }
+
+    return traits_type::not_eof(c);
+  }
+
+  void reserve(std::size_t n)
+  {
+    // Get current stream positions as offsets.
+    std::size_t gnext = gptr() - &buffer_[0];
+    std::size_t pnext = pptr() - &buffer_[0];
+    std::size_t pend = epptr() - &buffer_[0];
+
+    // Check if there is already enough space in the put area.
+    if (n <= pend - pnext)
+    {
+      return;
+    }
+
+    // Shift existing contents of get area to start of buffer.
+    if (gnext > 0)
+    {
+      pnext -= gnext;
+      std::memmove(&buffer_[0], &buffer_[0] + gnext, pnext);
+    }
+
+    // Ensure buffer is large enough to hold at least the specified size.
+    if (n > pend - pnext)
+    {
+      if (n <= max_size_ && pnext <= max_size_ - n)
+      {
+        pend = pnext + n;
+        buffer_.resize((std::max<std::size_t>)(pend, 1));
+      }
+      else
+      {
+        std::length_error ex("asio::streambuf too long");
+        asio::detail::throw_exception(ex);
+      }
+    }
+
+    // Update stream positions.
+    setg(&buffer_[0], &buffer_[0], &buffer_[0] + pnext);
+    setp(&buffer_[0] + pnext, &buffer_[0] + pend);
+  }
+
+private:
+  std::size_t max_size_;
+  std::vector<char_type, Allocator> buffer_;
+
+  // Helper function to get the preferred size for reading data.
+  friend std::size_t read_size_helper(
+      basic_streambuf& sb, std::size_t max_size)
+  {
+    return std::min<std::size_t>(
+        std::max<std::size_t>(512, sb.buffer_.capacity() - sb.size()),
+        std::min<std::size_t>(max_size, sb.max_size() - sb.size()));
+  }
+};
+
+/// Adapts basic_streambuf to the dynamic buffer sequence type requirements.
+#if defined(GENERATING_DOCUMENTATION)
+template <typename Allocator = std::allocator<char> >
+#else
+template <typename Allocator>
+#endif
+class basic_streambuf_ref
+{
+public:
+  /// The type used to represent the input sequence as a list of buffers.
+  typedef typename basic_streambuf<Allocator>::const_buffers_type
+    const_buffers_type;
+
+  /// The type used to represent the output sequence as a list of buffers.
+  typedef typename basic_streambuf<Allocator>::mutable_buffers_type
+    mutable_buffers_type;
+
+  /// Construct a basic_streambuf_ref for the given basic_streambuf object.
+  explicit basic_streambuf_ref(basic_streambuf<Allocator>& sb)
+    : sb_(sb)
+  {
+  }
+
+  /// Copy construct a basic_streambuf_ref.
+  basic_streambuf_ref(const basic_streambuf_ref& other) ASIO_NOEXCEPT
+    : sb_(other.sb_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move construct a basic_streambuf_ref.
+  basic_streambuf_ref(basic_streambuf_ref&& other) ASIO_NOEXCEPT
+    : sb_(other.sb_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get the size of the input sequence.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return sb_.size();
+  }
+
+  /// Get the maximum size of the dynamic buffer.
+  std::size_t max_size() const ASIO_NOEXCEPT
+  {
+    return sb_.max_size();
+  }
+
+  /// Get the current capacity of the dynamic buffer.
+  std::size_t capacity() const ASIO_NOEXCEPT
+  {
+    return sb_.capacity();
+  }
+
+  /// Get a list of buffers that represents the input sequence.
+  const_buffers_type data() const ASIO_NOEXCEPT
+  {
+    return sb_.data();
+  }
+
+  /// Get a list of buffers that represents the output sequence, with the given
+  /// size.
+  mutable_buffers_type prepare(std::size_t n)
+  {
+    return sb_.prepare(n);
+  }
+
+  /// Move bytes from the output sequence to the input sequence.
+  void commit(std::size_t n)
+  {
+    return sb_.commit(n);
+  }
+
+  /// Remove characters from the input sequence.
+  void consume(std::size_t n)
+  {
+    return sb_.consume(n);
+  }
+
+private:
+  basic_streambuf<Allocator>& sb_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_BASIC_STREAMBUF_HPP
diff --git a/subprojects/asio/include/asio/basic_streambuf_fwd.hpp b/subprojects/asio/include/asio/basic_streambuf_fwd.hpp
new file mode 100644
index 000000000..ed54fe956
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_streambuf_fwd.hpp
@@ -0,0 +1,36 @@
+//
+// basic_streambuf_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_STREAMBUF_FWD_HPP
+#define ASIO_BASIC_STREAMBUF_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include <memory>
+
+namespace asio {
+
+template <typename Allocator = std::allocator<char> >
+class basic_streambuf;
+
+template <typename Allocator = std::allocator<char> >
+class basic_streambuf_ref;
+
+} // namespace asio
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_BASIC_STREAMBUF_FWD_HPP
diff --git a/subprojects/asio/include/asio/basic_waitable_timer.hpp b/subprojects/asio/include/asio/basic_waitable_timer.hpp
new file mode 100644
index 000000000..22b85a698
--- /dev/null
+++ b/subprojects/asio/include/asio/basic_waitable_timer.hpp
@@ -0,0 +1,705 @@
+//
+// basic_waitable_timer.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BASIC_WAITABLE_TIMER_HPP
+#define ASIO_BASIC_WAITABLE_TIMER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/wait_traits.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/waitable_timer_service.hpp"
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/detail/chrono_time_traits.hpp"
+# include "asio/detail/deadline_timer_service.hpp"
+# define ASIO_SVC_T \
+    detail::deadline_timer_service< \
+      detail::chrono_time_traits<Clock, WaitTraits> >
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if !defined(ASIO_BASIC_WAITABLE_TIMER_FWD_DECL)
+#define ASIO_BASIC_WAITABLE_TIMER_FWD_DECL
+
+// Forward declaration with defaulted arguments.
+template <typename Clock,
+    typename WaitTraits = asio::wait_traits<Clock>
+    ASIO_SVC_TPARAM_DEF2(= waitable_timer_service<Clock, WaitTraits>)>
+class basic_waitable_timer;
+
+#endif // !defined(ASIO_BASIC_WAITABLE_TIMER_FWD_DECL)
+
+/// Provides waitable timer functionality.
+/**
+ * The basic_waitable_timer class template provides the ability to perform a
+ * blocking or asynchronous wait for a timer to expire.
+ *
+ * A waitable timer is always in one of two states: "expired" or "not expired".
+ * If the wait() or async_wait() function is called on an expired timer, the
+ * wait operation will complete immediately.
+ *
+ * Most applications will use one of the asio::steady_timer,
+ * asio::system_timer or asio::high_resolution_timer typedefs.
+ *
+ * @note This waitable timer functionality is for use with the C++11 standard
+ * library's @c &lt;chrono&gt; facility, or with the Boost.Chrono library.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Examples
+ * Performing a blocking wait (C++11):
+ * @code
+ * // Construct a timer without setting an expiry time.
+ * asio::steady_timer timer(io_context);
+ *
+ * // Set an expiry time relative to now.
+ * timer.expires_after(std::chrono::seconds(5));
+ *
+ * // Wait for the timer to expire.
+ * timer.wait();
+ * @endcode
+ *
+ * @par 
+ * Performing an asynchronous wait (C++11):
+ * @code
+ * void handler(const asio::error_code& error)
+ * {
+ *   if (!error)
+ *   {
+ *     // Timer expired.
+ *   }
+ * }
+ *
+ * ...
+ *
+ * // Construct a timer with an absolute expiry time.
+ * asio::steady_timer timer(io_context,
+ *     std::chrono::steady_clock::now() + std::chrono::seconds(60));
+ *
+ * // Start an asynchronous wait.
+ * timer.async_wait(handler);
+ * @endcode
+ *
+ * @par Changing an active waitable timer's expiry time
+ *
+ * Changing the expiry time of a timer while there are pending asynchronous
+ * waits causes those wait operations to be cancelled. To ensure that the action
+ * associated with the timer is performed only once, use something like this:
+ * used:
+ *
+ * @code
+ * void on_some_event()
+ * {
+ *   if (my_timer.expires_after(seconds(5)) > 0)
+ *   {
+ *     // We managed to cancel the timer. Start new asynchronous wait.
+ *     my_timer.async_wait(on_timeout);
+ *   }
+ *   else
+ *   {
+ *     // Too late, timer has already expired!
+ *   }
+ * }
+ *
+ * void on_timeout(const asio::error_code& e)
+ * {
+ *   if (e != asio::error::operation_aborted)
+ *   {
+ *     // Timer was not cancelled, take necessary action.
+ *   }
+ * }
+ * @endcode
+ *
+ * @li The asio::basic_waitable_timer::expires_after() function
+ * cancels any pending asynchronous waits, and returns the number of
+ * asynchronous waits that were cancelled. If it returns 0 then you were too
+ * late and the wait handler has already been executed, or will soon be
+ * executed. If it returns 1 then the wait handler was successfully cancelled.
+ *
+ * @li If a wait handler is cancelled, the asio::error_code passed to
+ * it contains the value asio::error::operation_aborted.
+ */
+template <typename Clock, typename WaitTraits ASIO_SVC_TPARAM>
+class basic_waitable_timer
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The clock type.
+  typedef Clock clock_type;
+
+  /// The duration type of the clock.
+  typedef typename clock_type::duration duration;
+
+  /// The time point type of the clock.
+  typedef typename clock_type::time_point time_point;
+
+  /// The wait traits type.
+  typedef WaitTraits traits_type;
+
+  /// Constructor.
+  /**
+   * This constructor creates a timer without setting an expiry time. The
+   * expires_at() or expires_after() functions must be called to set an expiry
+   * time before the timer can be waited on.
+   *
+   * @param io_context The io_context object that the timer will use to dispatch
+   * handlers for any asynchronous operations performed on the timer.
+   */
+  explicit basic_waitable_timer(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Constructor to set a particular expiry time as an absolute time.
+  /**
+   * This constructor creates a timer and sets the expiry time.
+   *
+   * @param io_context The io_context object that the timer will use to dispatch
+   * handlers for any asynchronous operations performed on the timer.
+   *
+   * @param expiry_time The expiry time to be used for the timer, expressed
+   * as an absolute time.
+   */
+  basic_waitable_timer(asio::io_context& io_context,
+      const time_point& expiry_time)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().expires_at(this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_at");
+  }
+
+  /// Constructor to set a particular expiry time relative to now.
+  /**
+   * This constructor creates a timer and sets the expiry time.
+   *
+   * @param io_context The io_context object that the timer will use to dispatch
+   * handlers for any asynchronous operations performed on the timer.
+   *
+   * @param expiry_time The expiry time to be used for the timer, relative to
+   * now.
+   */
+  basic_waitable_timer(asio::io_context& io_context,
+      const duration& expiry_time)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().expires_after(
+        this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_after");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_waitable_timer from another.
+  /**
+   * This constructor moves a timer from one object to another.
+   *
+   * @param other The other basic_waitable_timer object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_waitable_timer(io_context&) constructor.
+   */
+  basic_waitable_timer(basic_waitable_timer&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_waitable_timer from another.
+  /**
+   * This assignment operator moves a timer from one object to another. Cancels
+   * any outstanding asynchronous operations associated with the target object.
+   *
+   * @param other The other basic_waitable_timer object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_waitable_timer(io_context&) constructor.
+   */
+  basic_waitable_timer& operator=(basic_waitable_timer&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the timer.
+  /**
+   * This function destroys the timer, cancelling any outstanding asynchronous
+   * wait operations associated with the timer as if by calling @c cancel.
+   */
+  ~basic_waitable_timer()
+  {
+  }
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  // These functions are provided by basic_io_object<>.
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+  /// Cancel any asynchronous operations that are waiting on the timer.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the timer. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel()
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+    return s;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use non-error_code overload.) Cancel any asynchronous
+  /// operations that are waiting on the timer.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the timer. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @note If the timer has already expired when cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel(asio::error_code& ec)
+  {
+    return this->get_service().cancel(this->get_implementation(), ec);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Cancels one asynchronous operation that is waiting on the timer.
+  /**
+   * This function forces the completion of one pending asynchronous wait
+   * operation against the timer. Handlers are cancelled in FIFO order. The
+   * handler for the cancelled operation will be invoked with the
+   * asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @return The number of asynchronous operations that were cancelled. That is,
+   * either 0 or 1.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when cancel_one() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel_one()
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().cancel_one(
+        this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel_one");
+    return s;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use non-error_code overload.) Cancels one asynchronous
+  /// operation that is waiting on the timer.
+  /**
+   * This function forces the completion of one pending asynchronous wait
+   * operation against the timer. Handlers are cancelled in FIFO order. The
+   * handler for the cancelled operation will be invoked with the
+   * asio::error::operation_aborted error code.
+   *
+   * Cancelling the timer does not change the expiry time.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled. That is,
+   * either 0 or 1.
+   *
+   * @note If the timer has already expired when cancel_one() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t cancel_one(asio::error_code& ec)
+  {
+    return this->get_service().cancel_one(this->get_implementation(), ec);
+  }
+
+  /// (Deprecated: Use expiry().) Get the timer's expiry time as an absolute
+  /// time.
+  /**
+   * This function may be used to obtain the timer's current expiry time.
+   * Whether the timer has expired or not does not affect this value.
+   */
+  time_point expires_at() const
+  {
+    return this->get_service().expires_at(this->get_implementation());
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the timer's expiry time as an absolute time.
+  /**
+   * This function may be used to obtain the timer's current expiry time.
+   * Whether the timer has expired or not does not affect this value.
+   */
+  time_point expiry() const
+  {
+    return this->get_service().expiry(this->get_implementation());
+  }
+
+  /// Set the timer's expiry time as an absolute time.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when expires_at() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_at(const time_point& expiry_time)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().expires_at(
+        this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_at");
+    return s;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use non-error_code overload.) Set the timer's expiry time as
+  /// an absolute time.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @note If the timer has already expired when expires_at() is called, then
+   * the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_at(const time_point& expiry_time,
+      asio::error_code& ec)
+  {
+    return this->get_service().expires_at(
+        this->get_implementation(), expiry_time, ec);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Set the timer's expiry time relative to now.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when expires_after() is called,
+   * then the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_after(const duration& expiry_time)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().expires_after(
+        this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_after");
+    return s;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use expiry().) Get the timer's expiry time relative to now.
+  /**
+   * This function may be used to obtain the timer's current expiry time.
+   * Whether the timer has expired or not does not affect this value.
+   */
+  duration expires_from_now() const
+  {
+    return this->get_service().expires_from_now(this->get_implementation());
+  }
+
+  /// (Deprecated: Use expires_after().) Set the timer's expiry time relative
+  /// to now.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If the timer has already expired when expires_from_now() is called,
+   * then the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_from_now(const duration& expiry_time)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().expires_from_now(
+        this->get_implementation(), expiry_time, ec);
+    asio::detail::throw_error(ec, "expires_from_now");
+    return s;
+  }
+
+  /// (Deprecated: Use expires_after().) Set the timer's expiry time relative
+  /// to now.
+  /**
+   * This function sets the expiry time. Any pending asynchronous wait
+   * operations will be cancelled. The handler for each cancelled operation will
+   * be invoked with the asio::error::operation_aborted error code.
+   *
+   * @param expiry_time The expiry time to be used for the timer.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of asynchronous operations that were cancelled.
+   *
+   * @note If the timer has already expired when expires_from_now() is called,
+   * then the handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  std::size_t expires_from_now(const duration& expiry_time,
+      asio::error_code& ec)
+  {
+    return this->get_service().expires_from_now(
+        this->get_implementation(), expiry_time, ec);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Perform a blocking wait on the timer.
+  /**
+   * This function is used to wait for the timer to expire. This function
+   * blocks and does not return until the timer has expired.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void wait()
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Perform a blocking wait on the timer.
+  /**
+   * This function is used to wait for the timer to expire. This function
+   * blocks and does not return until the timer has expired.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  void wait(asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), ec);
+  }
+
+  /// Start an asynchronous wait on the timer.
+  /**
+   * This function may be used to initiate an asynchronous wait against the
+   * timer. It always returns immediately.
+   *
+   * For each call to async_wait(), the supplied handler will be called exactly
+   * once. The handler will be called when:
+   *
+   * @li The timer has expired.
+   *
+   * @li The timer was cancelled, in which case the handler is passed the error
+   * code asio::error::operation_aborted.
+   *
+   * @param handler The handler to be called when the timer expires. Copies
+   * will be made of the handler as required. The function signature of the
+   * handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WaitHandler.
+    ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_wait(this->get_implementation(),
+        ASIO_MOVE_CAST(WaitHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_wait(this->get_implementation(),
+        init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+private:
+  // Disallow copying and assignment.
+  basic_waitable_timer(const basic_waitable_timer&) ASIO_DELETED;
+  basic_waitable_timer& operator=(
+      const basic_waitable_timer&) ASIO_DELETED;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# undef ASIO_SVC_T
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_BASIC_WAITABLE_TIMER_HPP
diff --git a/subprojects/asio/include/asio/bind_executor.hpp b/subprojects/asio/include/asio/bind_executor.hpp
new file mode 100644
index 000000000..9e2094b54
--- /dev/null
+++ b/subprojects/asio/include/asio/bind_executor.hpp
@@ -0,0 +1,611 @@
+//
+// bind_executor.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BIND_EXECUTOR_HPP
+#define ASIO_BIND_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/detail/variadic_templates.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/async_result.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/is_executor.hpp"
+#include "asio/uses_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+struct executor_binder_check
+{
+  typedef void type;
+};
+
+// Helper to automatically define nested typedef result_type.
+
+template <typename T, typename = void>
+struct executor_binder_result_type
+{
+protected:
+  typedef void result_type_or_void;
+};
+
+template <typename T>
+struct executor_binder_result_type<T,
+  typename executor_binder_check<typename T::result_type>::type>
+{
+  typedef typename T::result_type result_type;
+protected:
+  typedef result_type result_type_or_void;
+};
+
+template <typename R>
+struct executor_binder_result_type<R(*)()>
+{
+  typedef R result_type;
+protected:
+  typedef result_type result_type_or_void;
+};
+
+template <typename R>
+struct executor_binder_result_type<R(&)()>
+{
+  typedef R result_type;
+protected:
+  typedef result_type result_type_or_void;
+};
+
+template <typename R, typename A1>
+struct executor_binder_result_type<R(*)(A1)>
+{
+  typedef R result_type;
+protected:
+  typedef result_type result_type_or_void;
+};
+
+template <typename R, typename A1>
+struct executor_binder_result_type<R(&)(A1)>
+{
+  typedef R result_type;
+protected:
+  typedef result_type result_type_or_void;
+};
+
+template <typename R, typename A1, typename A2>
+struct executor_binder_result_type<R(*)(A1, A2)>
+{
+  typedef R result_type;
+protected:
+  typedef result_type result_type_or_void;
+};
+
+template <typename R, typename A1, typename A2>
+struct executor_binder_result_type<R(&)(A1, A2)>
+{
+  typedef R result_type;
+protected:
+  typedef result_type result_type_or_void;
+};
+
+// Helper to automatically define nested typedef argument_type.
+
+template <typename T, typename = void>
+struct executor_binder_argument_type {};
+
+template <typename T>
+struct executor_binder_argument_type<T,
+  typename executor_binder_check<typename T::argument_type>::type>
+{
+  typedef typename T::argument_type argument_type;
+};
+
+template <typename R, typename A1>
+struct executor_binder_argument_type<R(*)(A1)>
+{
+  typedef A1 argument_type;
+};
+
+template <typename R, typename A1>
+struct executor_binder_argument_type<R(&)(A1)>
+{
+  typedef A1 argument_type;
+};
+
+// Helper to automatically define nested typedefs first_argument_type and
+// second_argument_type.
+
+template <typename T, typename = void>
+struct executor_binder_argument_types {};
+
+template <typename T>
+struct executor_binder_argument_types<T,
+  typename executor_binder_check<typename T::first_argument_type>::type>
+{
+  typedef typename T::first_argument_type first_argument_type;
+  typedef typename T::second_argument_type second_argument_type;
+};
+
+template <typename R, typename A1, typename A2>
+struct executor_binder_argument_type<R(*)(A1, A2)>
+{
+  typedef A1 first_argument_type;
+  typedef A2 second_argument_type;
+};
+
+template <typename R, typename A1, typename A2>
+struct executor_binder_argument_type<R(&)(A1, A2)>
+{
+  typedef A1 first_argument_type;
+  typedef A2 second_argument_type;
+};
+
+// Helper to:
+// - Apply the empty base optimisation to the executor.
+// - Perform uses_executor construction of the target type, if required.
+
+template <typename T, typename Executor, bool UsesExecutor>
+class executor_binder_base;
+
+template <typename T, typename Executor>
+class executor_binder_base<T, Executor, true>
+  : protected Executor
+{
+protected:
+  template <typename E, typename U>
+  executor_binder_base(ASIO_MOVE_ARG(E) e, ASIO_MOVE_ARG(U) u)
+    : executor_(ASIO_MOVE_CAST(E)(e)),
+      target_(executor_arg_t(), executor_, ASIO_MOVE_CAST(U)(u))
+  {
+  }
+
+  Executor executor_;
+  T target_;
+};
+
+template <typename T, typename Executor>
+class executor_binder_base<T, Executor, false>
+{
+protected:
+  template <typename E, typename U>
+  executor_binder_base(ASIO_MOVE_ARG(E) e, ASIO_MOVE_ARG(U) u)
+    : executor_(ASIO_MOVE_CAST(E)(e)),
+      target_(ASIO_MOVE_CAST(U)(u))
+  {
+  }
+
+  Executor executor_;
+  T target_;
+};
+
+// Helper to enable SFINAE on zero-argument operator() below.
+
+template <typename T, typename = void>
+struct executor_binder_result_of0
+{
+  typedef void type;
+};
+
+template <typename T>
+struct executor_binder_result_of0<T,
+  typename executor_binder_check<typename result_of<T()>::type>::type>
+{
+  typedef typename result_of<T()>::type type;
+};
+
+} // namespace detail
+
+/// A call wrapper type to bind an executor of type @c Executor to an object of
+/// type @c T.
+template <typename T, typename Executor>
+class executor_binder
+#if !defined(GENERATING_DOCUMENTATION)
+  : public detail::executor_binder_result_type<T>,
+    public detail::executor_binder_argument_type<T>,
+    public detail::executor_binder_argument_types<T>,
+    private detail::executor_binder_base<
+      T, Executor, uses_executor<T, Executor>::value>
+#endif // !defined(GENERATING_DOCUMENTATION)
+{
+public:
+  /// The type of the target object.
+  typedef T target_type;
+
+  /// The type of the associated executor.
+  typedef Executor executor_type;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// The return type if a function.
+  /**
+   * The type of @c result_type is based on the type @c T of the wrapper's
+   * target object:
+   *
+   * @li if @c T is a pointer to function type, @c result_type is a synonym for
+   * the return type of @c T;
+   *
+   * @li if @c T is a class type with a member type @c result_type, then @c
+   * result_type is a synonym for @c T::result_type;
+   *
+   * @li otherwise @c result_type is not defined.
+   */
+  typedef see_below result_type;
+
+  /// The type of the function's argument.
+  /**
+   * The type of @c argument_type is based on the type @c T of the wrapper's
+   * target object:
+   *
+   * @li if @c T is a pointer to a function type accepting a single argument,
+   * @c argument_type is a synonym for the return type of @c T;
+   *
+   * @li if @c T is a class type with a member type @c argument_type, then @c
+   * argument_type is a synonym for @c T::argument_type;
+   *
+   * @li otherwise @c argument_type is not defined.
+   */
+  typedef see_below argument_type;
+
+  /// The type of the function's first argument.
+  /**
+   * The type of @c first_argument_type is based on the type @c T of the
+   * wrapper's target object:
+   *
+   * @li if @c T is a pointer to a function type accepting two arguments, @c
+   * first_argument_type is a synonym for the return type of @c T;
+   *
+   * @li if @c T is a class type with a member type @c first_argument_type,
+   * then @c first_argument_type is a synonym for @c T::first_argument_type;
+   *
+   * @li otherwise @c first_argument_type is not defined.
+   */
+  typedef see_below first_argument_type;
+
+  /// The type of the function's second argument.
+  /**
+   * The type of @c second_argument_type is based on the type @c T of the
+   * wrapper's target object:
+   *
+   * @li if @c T is a pointer to a function type accepting two arguments, @c
+   * second_argument_type is a synonym for the return type of @c T;
+   *
+   * @li if @c T is a class type with a member type @c first_argument_type,
+   * then @c second_argument_type is a synonym for @c T::second_argument_type;
+   *
+   * @li otherwise @c second_argument_type is not defined.
+   */
+  typedef see_below second_argument_type;
+#endif // defined(GENERATING_DOCUMENTATION)
+
+  /// Construct an executor wrapper for the specified object.
+  /**
+   * This constructor is only valid if the type @c T is constructible from type
+   * @c U.
+   */
+  template <typename U>
+  executor_binder(executor_arg_t, const executor_type& e,
+      ASIO_MOVE_ARG(U) u)
+    : base_type(e, ASIO_MOVE_CAST(U)(u))
+  {
+  }
+
+  /// Copy constructor.
+  executor_binder(const executor_binder& other)
+    : base_type(other.get_executor(), other.get())
+  {
+  }
+
+  /// Construct a copy, but specify a different executor.
+  executor_binder(executor_arg_t, const executor_type& e,
+      const executor_binder& other)
+    : base_type(e, other.get())
+  {
+  }
+
+  /// Construct a copy of a different executor wrapper type.
+  /**
+   * This constructor is only valid if the @c Executor type is constructible
+   * from type @c OtherExecutor, and the type @c T is constructible from type
+   * @c U.
+   */
+  template <typename U, typename OtherExecutor>
+  executor_binder(const executor_binder<U, OtherExecutor>& other)
+    : base_type(other.get_executor(), other.get())
+  {
+  }
+
+  /// Construct a copy of a different executor wrapper type, but specify a
+  /// different executor.
+  /**
+   * This constructor is only valid if the type @c T is constructible from type
+   * @c U.
+   */
+  template <typename U, typename OtherExecutor>
+  executor_binder(executor_arg_t, const executor_type& e,
+      const executor_binder<U, OtherExecutor>& other)
+    : base_type(e, other.get())
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Move constructor.
+  executor_binder(executor_binder&& other)
+    : base_type(ASIO_MOVE_CAST(executor_type)(other.get_executor()),
+        ASIO_MOVE_CAST(T)(other.get()))
+  {
+  }
+
+  /// Move construct the target object, but specify a different executor.
+  executor_binder(executor_arg_t, const executor_type& e,
+      executor_binder&& other)
+    : base_type(e, ASIO_MOVE_CAST(T)(other.get()))
+  {
+  }
+
+  /// Move construct from a different executor wrapper type.
+  template <typename U, typename OtherExecutor>
+  executor_binder(executor_binder<U, OtherExecutor>&& other)
+    : base_type(ASIO_MOVE_CAST(OtherExecutor)(other.get_executor()),
+        ASIO_MOVE_CAST(U)(other.get()))
+  {
+  }
+
+  /// Move construct from a different executor wrapper type, but specify a
+  /// different executor.
+  template <typename U, typename OtherExecutor>
+  executor_binder(executor_arg_t, const executor_type& e,
+      executor_binder<U, OtherExecutor>&& other)
+    : base_type(e, ASIO_MOVE_CAST(U)(other.get()))
+  {
+  }
+
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destructor.
+  ~executor_binder()
+  {
+  }
+
+  /// Obtain a reference to the target object.
+  target_type& get() ASIO_NOEXCEPT
+  {
+    return this->target_;
+  }
+
+  /// Obtain a reference to the target object.
+  const target_type& get() const ASIO_NOEXCEPT
+  {
+    return this->target_;
+  }
+
+  /// Obtain the associated executor.
+  executor_type get_executor() const ASIO_NOEXCEPT
+  {
+    return this->executor_;
+  }
+
+#if defined(GENERATING_DOCUMENTATION)
+
+  template <typename... Args> auto operator()(Args&& ...);
+  template <typename... Args> auto operator()(Args&& ...) const;
+
+#elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  /// Forwarding function call operator.
+  template <typename... Args>
+  typename result_of<T(Args...)>::type operator()(
+      ASIO_MOVE_ARG(Args)... args)
+  {
+    return this->target_(ASIO_MOVE_CAST(Args)(args)...);
+  }
+
+  /// Forwarding function call operator.
+  template <typename... Args>
+  typename result_of<T(Args...)>::type operator()(
+      ASIO_MOVE_ARG(Args)... args) const
+  {
+    return this->target_(ASIO_MOVE_CAST(Args)(args)...);
+  }
+
+#elif defined(ASIO_HAS_STD_TYPE_TRAITS) && !defined(_MSC_VER)
+
+  typename detail::executor_binder_result_of0<T>::type operator()()
+  {
+    return this->target_();
+  }
+
+  typename detail::executor_binder_result_of0<T>::type operator()() const
+  {
+    return this->target_();
+  }
+
+#define ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  typename result_of<T(ASIO_VARIADIC_TARGS(n))>::type operator()( \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
+  } \
+  \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  typename result_of<T(ASIO_VARIADIC_TARGS(n))>::type operator()( \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) const \
+  { \
+    return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF)
+#undef ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF
+
+#else // defined(ASIO_HAS_STD_TYPE_TRAITS) && !defined(_MSC_VER)
+
+  typedef typename detail::executor_binder_result_type<T>::result_type_or_void
+    result_type_or_void;
+
+  result_type_or_void operator()()
+  {
+    return this->target_();
+  }
+
+  result_type_or_void operator()() const
+  {
+    return this->target_();
+  }
+
+#define ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  result_type_or_void operator()( \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
+  } \
+  \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  result_type_or_void operator()( \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) const \
+  { \
+    return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF)
+#undef ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF
+
+#endif // defined(ASIO_HAS_STD_TYPE_TRAITS) && !defined(_MSC_VER)
+
+private:
+  typedef detail::executor_binder_base<T, Executor,
+    uses_executor<T, Executor>::value> base_type;
+};
+
+/// Associate an object of type @c T with an executor of type @c Executor.
+template <typename Executor, typename T>
+inline executor_binder<typename decay<T>::type, Executor>
+bind_executor(const Executor& ex, ASIO_MOVE_ARG(T) t,
+    typename enable_if<is_executor<Executor>::value>::type* = 0)
+{
+  return executor_binder<typename decay<T>::type, Executor>(
+      executor_arg_t(), ex, ASIO_MOVE_CAST(T)(t));
+}
+
+/// Associate an object of type @c T with an execution context's executor.
+template <typename ExecutionContext, typename T>
+inline executor_binder<typename decay<T>::type,
+  typename ExecutionContext::executor_type>
+bind_executor(ExecutionContext& ctx, ASIO_MOVE_ARG(T) t,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type* = 0)
+{
+  return executor_binder<typename decay<T>::type,
+    typename ExecutionContext::executor_type>(
+      executor_arg_t(), ctx.get_executor(), ASIO_MOVE_CAST(T)(t));
+}
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename T, typename Executor>
+struct uses_executor<executor_binder<T, Executor>, Executor>
+  : true_type {};
+
+template <typename T, typename Executor, typename Signature>
+class async_result<executor_binder<T, Executor>, Signature>
+{
+public:
+  typedef executor_binder<
+    typename async_result<T, Signature>::completion_handler_type, Executor>
+      completion_handler_type;
+
+  typedef typename async_result<T, Signature>::return_type return_type;
+
+  explicit async_result(executor_binder<T, Executor>& b)
+    : target_(b.get())
+  {
+  }
+
+  return_type get()
+  {
+    return target_.get();
+  }
+
+private:
+  async_result(const async_result&) ASIO_DELETED;
+  async_result& operator=(const async_result&) ASIO_DELETED;
+
+  async_result<T, Signature> target_;
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+template <typename T, typename Executor, typename Signature>
+struct handler_type<executor_binder<T, Executor>, Signature>
+{
+  typedef executor_binder<
+    typename handler_type<T, Signature>::type, Executor> type;
+};
+
+template <typename T, typename Executor>
+class async_result<executor_binder<T, Executor> >
+{
+public:
+  typedef typename async_result<T>::type type;
+
+  explicit async_result(executor_binder<T, Executor>& b)
+    : target_(b.get())
+  {
+  }
+
+  type get()
+  {
+    return target_.get();
+  }
+
+private:
+  async_result<T> target_;
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename T, typename Executor, typename Allocator>
+struct associated_allocator<executor_binder<T, Executor>, Allocator>
+{
+  typedef typename associated_allocator<T, Allocator>::type type;
+
+  static type get(const executor_binder<T, Executor>& b,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<T, Allocator>::get(b.get(), a);
+  }
+};
+
+template <typename T, typename Executor, typename Executor1>
+struct associated_executor<executor_binder<T, Executor>, Executor1>
+{
+  typedef Executor type;
+
+  static type get(const executor_binder<T, Executor>& b,
+      const Executor1& = Executor1()) ASIO_NOEXCEPT
+  {
+    return b.get_executor();
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BIND_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/buffer.hpp b/subprojects/asio/include/asio/buffer.hpp
new file mode 100644
index 000000000..56a14880d
--- /dev/null
+++ b/subprojects/asio/include/asio/buffer.hpp
@@ -0,0 +1,2169 @@
+//
+// buffer.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFER_HPP
+#define ASIO_BUFFER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <cstring>
+#include <limits>
+#include <stdexcept>
+#include <string>
+#include <vector>
+#include "asio/detail/array_fwd.hpp"
+#include "asio/detail/string_view.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#if defined(ASIO_MSVC) && (ASIO_MSVC >= 1700)
+# if defined(_HAS_ITERATOR_DEBUGGING) && (_HAS_ITERATOR_DEBUGGING != 0)
+#  if !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+#   define ASIO_ENABLE_BUFFER_DEBUGGING
+#  endif // !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+# endif // defined(_HAS_ITERATOR_DEBUGGING)
+#endif // defined(ASIO_MSVC) && (ASIO_MSVC >= 1700)
+
+#if defined(__GNUC__)
+# if defined(_GLIBCXX_DEBUG)
+#  if !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+#   define ASIO_ENABLE_BUFFER_DEBUGGING
+#  endif // !defined(ASIO_DISABLE_BUFFER_DEBUGGING)
+# endif // defined(_GLIBCXX_DEBUG)
+#endif // defined(__GNUC__)
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+# include "asio/detail/functional.hpp"
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+#if defined(ASIO_HAS_BOOST_WORKAROUND)
+# include <boost/detail/workaround.hpp>
+# if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582)) \
+    || BOOST_WORKAROUND(__SUNPRO_CC, BOOST_TESTED_AT(0x590))
+#  define ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND
+# endif // BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582))
+        // || BOOST_WORKAROUND(__SUNPRO_CC, BOOST_TESTED_AT(0x590))
+#endif // defined(ASIO_HAS_BOOST_WORKAROUND)
+
+#if defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+# include "asio/detail/type_traits.hpp"
+#endif // defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class mutable_buffer;
+class const_buffer;
+
+/// Holds a buffer that can be modified.
+/**
+ * The mutable_buffer class provides a safe representation of a buffer that can
+ * be modified. It does not own the underlying data, and so is cheap to copy or
+ * assign.
+ *
+ * @par Accessing Buffer Contents
+ *
+ * The contents of a buffer may be accessed using the @c data() and @c size()
+ * member functions:
+ *
+ * @code asio::mutable_buffer b1 = ...;
+ * std::size_t s1 = b1.size();
+ * unsigned char* p1 = static_cast<unsigned char*>(b1.data());
+ * @endcode
+ *
+ * The @c data() member function permits violations of type safety, so uses of
+ * it in application code should be carefully considered.
+ */
+class mutable_buffer
+{
+public:
+  /// Construct an empty buffer.
+  mutable_buffer() ASIO_NOEXCEPT
+    : data_(0),
+      size_(0)
+  {
+  }
+
+  /// Construct a buffer to represent a given memory range.
+  mutable_buffer(void* data, std::size_t size) ASIO_NOEXCEPT
+    : data_(data),
+      size_(size)
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  mutable_buffer(void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : data_(data),
+      size_(size),
+      debug_check_(debug_check)
+  {
+  }
+
+  const asio::detail::function<void()>& get_debug_check() const
+  {
+    return debug_check_;
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Get a pointer to the beginning of the memory range.
+  void* data() const ASIO_NOEXCEPT
+  {
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    if (size_ && debug_check_)
+      debug_check_();
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+    return data_;
+  }
+
+  /// Get the size of the memory range.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Move the start of the buffer by the specified number of bytes.
+  mutable_buffer& operator+=(std::size_t n) ASIO_NOEXCEPT
+  {
+    std::size_t offset = n < size_ ? n : size_;
+    data_ = static_cast<char*>(data_) + offset;
+    size_ -= offset;
+    return *this;
+  }
+
+private:
+  void* data_;
+  std::size_t size_;
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  asio::detail::function<void()> debug_check_;
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+/// (Deprecated: Use mutable_buffer.) Adapts a single modifiable buffer so that
+/// it meets the requirements of the MutableBufferSequence concept.
+class mutable_buffers_1
+  : public mutable_buffer
+{
+public:
+  /// The type for each element in the list of buffers.
+  typedef mutable_buffer value_type;
+
+  /// A random-access iterator type that may be used to read elements.
+  typedef const mutable_buffer* const_iterator;
+
+  /// Construct to represent a given memory range.
+  mutable_buffers_1(void* data, std::size_t size) ASIO_NOEXCEPT
+    : mutable_buffer(data, size)
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  mutable_buffers_1(void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : mutable_buffer(data, size, debug_check)
+  {
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Construct to represent a single modifiable buffer.
+  explicit mutable_buffers_1(const mutable_buffer& b) ASIO_NOEXCEPT
+    : mutable_buffer(b)
+  {
+  }
+
+  /// Get a random-access iterator to the first element.
+  const_iterator begin() const ASIO_NOEXCEPT
+  {
+    return this;
+  }
+
+  /// Get a random-access iterator for one past the last element.
+  const_iterator end() const ASIO_NOEXCEPT
+  {
+    return begin() + 1;
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Holds a buffer that cannot be modified.
+/**
+ * The const_buffer class provides a safe representation of a buffer that cannot
+ * be modified. It does not own the underlying data, and so is cheap to copy or
+ * assign.
+ *
+ * @par Accessing Buffer Contents
+ *
+ * The contents of a buffer may be accessed using the @c data() and @c size()
+ * member functions:
+ *
+ * @code asio::const_buffer b1 = ...;
+ * std::size_t s1 = b1.size();
+ * const unsigned char* p1 = static_cast<const unsigned char*>(b1.data());
+ * @endcode
+ *
+ * The @c data() member function permits violations of type safety, so uses of
+ * it in application code should be carefully considered.
+ */
+class const_buffer
+{
+public:
+  /// Construct an empty buffer.
+  const_buffer() ASIO_NOEXCEPT
+    : data_(0),
+      size_(0)
+  {
+  }
+
+  /// Construct a buffer to represent a given memory range.
+  const_buffer(const void* data, std::size_t size) ASIO_NOEXCEPT
+    : data_(data),
+      size_(size)
+  {
+  }
+
+  /// Construct a non-modifiable buffer from a modifiable one.
+  const_buffer(const mutable_buffer& b) ASIO_NOEXCEPT
+    : data_(b.data()),
+      size_(b.size())
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , debug_check_(b.get_debug_check())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  const_buffer(const void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : data_(data),
+      size_(size),
+      debug_check_(debug_check)
+  {
+  }
+
+  const asio::detail::function<void()>& get_debug_check() const
+  {
+    return debug_check_;
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Get a pointer to the beginning of the memory range.
+  const void* data() const ASIO_NOEXCEPT
+  {
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    if (size_ && debug_check_)
+      debug_check_();
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+    return data_;
+  }
+
+  /// Get the size of the memory range.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Move the start of the buffer by the specified number of bytes.
+  const_buffer& operator+=(std::size_t n) ASIO_NOEXCEPT
+  {
+    std::size_t offset = n < size_ ? n : size_;
+    data_ = static_cast<const char*>(data_) + offset;
+    size_ -= offset;
+    return *this;
+  }
+
+private:
+  const void* data_;
+  std::size_t size_;
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  asio::detail::function<void()> debug_check_;
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+/// (Deprecated: Use const_buffer.) Adapts a single non-modifiable buffer so
+/// that it meets the requirements of the ConstBufferSequence concept.
+class const_buffers_1
+  : public const_buffer
+{
+public:
+  /// The type for each element in the list of buffers.
+  typedef const_buffer value_type;
+
+  /// A random-access iterator type that may be used to read elements.
+  typedef const const_buffer* const_iterator;
+
+  /// Construct to represent a given memory range.
+  const_buffers_1(const void* data, std::size_t size) ASIO_NOEXCEPT
+    : const_buffer(data, size)
+  {
+  }
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+  const_buffers_1(const void* data, std::size_t size,
+      asio::detail::function<void()> debug_check)
+    : const_buffer(data, size, debug_check)
+  {
+  }
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+  /// Construct to represent a single non-modifiable buffer.
+  explicit const_buffers_1(const const_buffer& b) ASIO_NOEXCEPT
+    : const_buffer(b)
+  {
+  }
+
+  /// Get a random-access iterator to the first element.
+  const_iterator begin() const ASIO_NOEXCEPT
+  {
+    return this;
+  }
+
+  /// Get a random-access iterator for one past the last element.
+  const_iterator end() const ASIO_NOEXCEPT
+  {
+    return begin() + 1;
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// (Deprecated: Use the socket/descriptor wait() and async_wait() member
+/// functions.) An implementation of both the ConstBufferSequence and
+/// MutableBufferSequence concepts to represent a null buffer sequence.
+class null_buffers
+{
+public:
+  /// The type for each element in the list of buffers.
+  typedef mutable_buffer value_type;
+
+  /// A random-access iterator type that may be used to read elements.
+  typedef const mutable_buffer* const_iterator;
+
+  /// Get a random-access iterator to the first element.
+  const_iterator begin() const ASIO_NOEXCEPT
+  {
+    return &buf_;
+  }
+
+  /// Get a random-access iterator for one past the last element.
+  const_iterator end() const ASIO_NOEXCEPT
+  {
+    return &buf_;
+  }
+
+private:
+  mutable_buffer buf_;
+};
+
+/** @defgroup buffer_sequence_begin asio::buffer_sequence_begin
+ *
+ * @brief The asio::buffer_sequence_begin function returns an iterator
+ * pointing to the first element in a buffer sequence.
+ */
+/*@{*/
+
+/// Get an iterator to the first element in a buffer sequence.
+inline const mutable_buffer* buffer_sequence_begin(const mutable_buffer& b)
+{
+  return &b;
+}
+
+/// Get an iterator to the first element in a buffer sequence.
+inline const const_buffer* buffer_sequence_begin(const const_buffer& b)
+{
+  return &b;
+}
+
+#if defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/// Get an iterator to the first element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_begin(C& c) -> decltype(c.begin())
+{
+  return c.begin();
+}
+
+/// Get an iterator to the first element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_begin(const C& c) -> decltype(c.begin())
+{
+  return c.begin();
+}
+
+#else // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+template <typename C>
+inline typename C::iterator buffer_sequence_begin(C& c)
+{
+  return c.begin();
+}
+
+template <typename C>
+inline typename C::const_iterator buffer_sequence_begin(const C& c)
+{
+  return c.begin();
+}
+
+#endif // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/*@}*/
+
+/** @defgroup buffer_sequence_end asio::buffer_sequence_end
+ *
+ * @brief The asio::buffer_sequence_end function returns an iterator
+ * pointing to one past the end element in a buffer sequence.
+ */
+/*@{*/
+
+/// Get an iterator to one past the end element in a buffer sequence.
+inline const mutable_buffer* buffer_sequence_end(const mutable_buffer& b)
+{
+  return &b + 1;
+}
+
+/// Get an iterator to one past the end element in a buffer sequence.
+inline const const_buffer* buffer_sequence_end(const const_buffer& b)
+{
+  return &b + 1;
+}
+
+#if defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/// Get an iterator to one past the end element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_end(C& c) -> decltype(c.end())
+{
+  return c.end();
+}
+
+/// Get an iterator to one past the end element in a buffer sequence.
+template <typename C>
+inline auto buffer_sequence_end(const C& c) -> decltype(c.end())
+{
+  return c.end();
+}
+
+#else // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+template <typename C>
+inline typename C::iterator buffer_sequence_end(C& c)
+{
+  return c.end();
+}
+
+template <typename C>
+inline typename C::const_iterator buffer_sequence_end(const C& c)
+{
+  return c.end();
+}
+
+#endif // defined(ASIO_HAS_DECLTYPE) || defined(GENERATING_DOCUMENTATION)
+
+/*@}*/
+
+namespace detail {
+
+// Tag types used to select appropriately optimised overloads.
+struct one_buffer {};
+struct multiple_buffers {};
+
+// Helper trait to detect single buffers.
+template <typename BufferSequence>
+struct buffer_sequence_cardinality :
+  conditional<
+    is_same<BufferSequence, mutable_buffer>::value
+#if !defined(ASIO_NO_DEPRECATED)
+      || is_same<BufferSequence, mutable_buffers_1>::value
+      || is_same<BufferSequence, const_buffers_1>::value
+#endif // !defined(ASIO_NO_DEPRECATED)
+      || is_same<BufferSequence, const_buffer>::value,
+    one_buffer, multiple_buffers>::type {};
+
+template <typename Iterator>
+inline std::size_t buffer_size(one_buffer,
+    Iterator begin, Iterator) ASIO_NOEXCEPT
+{
+  return const_buffer(*begin).size();
+}
+
+template <typename Iterator>
+inline std::size_t buffer_size(multiple_buffers,
+    Iterator begin, Iterator end) ASIO_NOEXCEPT
+{
+  std::size_t total_buffer_size = 0;
+
+  Iterator iter = begin;
+  for (; iter != end; ++iter)
+  {
+    const_buffer b(*iter);
+    total_buffer_size += b.size();
+  }
+
+  return total_buffer_size;
+}
+
+} // namespace detail
+
+/// Get the total number of bytes in a buffer sequence.
+/**
+ * The @c buffer_size function determines the total size of all buffers in the
+ * buffer sequence, as if computed as follows:
+ *
+ * @code size_t total_size = 0;
+ * auto i = asio::buffer_sequence_begin(buffers);
+ * auto end = asio::buffer_sequence_end(buffers);
+ * for (; i != end; ++i)
+ * {
+ *   const_buffer b(*i);
+ *   total_size += b.size();
+ * }
+ * return total_size; @endcode
+ *
+ * The @c BufferSequence template parameter may meet either of the @c
+ * ConstBufferSequence or @c MutableBufferSequence type requirements.
+ */
+template <typename BufferSequence>
+inline std::size_t buffer_size(const BufferSequence& b) ASIO_NOEXCEPT
+{
+  return detail::buffer_size(
+      detail::buffer_sequence_cardinality<BufferSequence>(),
+      asio::buffer_sequence_begin(b),
+      asio::buffer_sequence_end(b));
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+/** @defgroup buffer_cast asio::buffer_cast
+ *
+ * @brief (Deprecated: Use the @c data() member function.) The
+ * asio::buffer_cast function is used to obtain a pointer to the
+ * underlying memory region associated with a buffer.
+ *
+ * @par Examples:
+ *
+ * To access the memory of a non-modifiable buffer, use:
+ * @code asio::const_buffer b1 = ...;
+ * const unsigned char* p1 = asio::buffer_cast<const unsigned char*>(b1);
+ * @endcode
+ *
+ * To access the memory of a modifiable buffer, use:
+ * @code asio::mutable_buffer b2 = ...;
+ * unsigned char* p2 = asio::buffer_cast<unsigned char*>(b2);
+ * @endcode
+ *
+ * The asio::buffer_cast function permits violations of type safety, so
+ * uses of it in application code should be carefully considered.
+ */
+/*@{*/
+
+/// Cast a non-modifiable buffer to a specified pointer to POD type.
+template <typename PointerToPodType>
+inline PointerToPodType buffer_cast(const mutable_buffer& b) ASIO_NOEXCEPT
+{
+  return static_cast<PointerToPodType>(b.data());
+}
+
+/// Cast a non-modifiable buffer to a specified pointer to POD type.
+template <typename PointerToPodType>
+inline PointerToPodType buffer_cast(const const_buffer& b) ASIO_NOEXCEPT
+{
+  return static_cast<PointerToPodType>(b.data());
+}
+
+/*@}*/
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Create a new modifiable buffer that is offset from the start of another.
+/**
+ * @relates mutable_buffer
+ */
+inline mutable_buffer operator+(const mutable_buffer& b,
+    std::size_t n) ASIO_NOEXCEPT
+{
+  std::size_t offset = n < b.size() ? n : b.size();
+  char* new_data = static_cast<char*>(b.data()) + offset;
+  std::size_t new_size = b.size() - offset;
+  return mutable_buffer(new_data, new_size
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that is offset from the start of another.
+/**
+ * @relates mutable_buffer
+ */
+inline mutable_buffer operator+(std::size_t n,
+    const mutable_buffer& b) ASIO_NOEXCEPT
+{
+  return b + n;
+}
+
+/// Create a new non-modifiable buffer that is offset from the start of another.
+/**
+ * @relates const_buffer
+ */
+inline const_buffer operator+(const const_buffer& b,
+    std::size_t n) ASIO_NOEXCEPT
+{
+  std::size_t offset = n < b.size() ? n : b.size();
+  const char* new_data = static_cast<const char*>(b.data()) + offset;
+  std::size_t new_size = b.size() - offset;
+  return const_buffer(new_data, new_size
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that is offset from the start of another.
+/**
+ * @relates const_buffer
+ */
+inline const_buffer operator+(std::size_t n,
+    const const_buffer& b) ASIO_NOEXCEPT
+{
+  return b + n;
+}
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+namespace detail {
+
+template <typename Iterator>
+class buffer_debug_check
+{
+public:
+  buffer_debug_check(Iterator iter)
+    : iter_(iter)
+  {
+  }
+
+  ~buffer_debug_check()
+  {
+#if defined(ASIO_MSVC) && (ASIO_MSVC == 1400)
+    // MSVC 8's string iterator checking may crash in a std::string::iterator
+    // object's destructor when the iterator points to an already-destroyed
+    // std::string object, unless the iterator is cleared first.
+    iter_ = Iterator();
+#endif // defined(ASIO_MSVC) && (ASIO_MSVC == 1400)
+  }
+
+  void operator()()
+  {
+    (void)*iter_;
+  }
+
+private:
+  Iterator iter_;
+};
+
+} // namespace detail
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+
+/** @defgroup buffer asio::buffer
+ *
+ * @brief The asio::buffer function is used to create a buffer object to
+ * represent raw memory, an array of POD elements, a vector of POD elements,
+ * or a std::string.
+ *
+ * A buffer object represents a contiguous region of memory as a 2-tuple
+ * consisting of a pointer and size in bytes. A tuple of the form <tt>{void*,
+ * size_t}</tt> specifies a mutable (modifiable) region of memory. Similarly, a
+ * tuple of the form <tt>{const void*, size_t}</tt> specifies a const
+ * (non-modifiable) region of memory. These two forms correspond to the classes
+ * mutable_buffer and const_buffer, respectively. To mirror C++'s conversion
+ * rules, a mutable_buffer is implicitly convertible to a const_buffer, and the
+ * opposite conversion is not permitted.
+ *
+ * The simplest use case involves reading or writing a single buffer of a
+ * specified size:
+ *
+ * @code sock.send(asio::buffer(data, size)); @endcode
+ *
+ * In the above example, the return value of asio::buffer meets the
+ * requirements of the ConstBufferSequence concept so that it may be directly
+ * passed to the socket's write function. A buffer created for modifiable
+ * memory also meets the requirements of the MutableBufferSequence concept.
+ *
+ * An individual buffer may be created from a builtin array, std::vector,
+ * std::array or boost::array of POD elements. This helps prevent buffer
+ * overruns by automatically determining the size of the buffer:
+ *
+ * @code char d1[128];
+ * size_t bytes_transferred = sock.receive(asio::buffer(d1));
+ *
+ * std::vector<char> d2(128);
+ * bytes_transferred = sock.receive(asio::buffer(d2));
+ *
+ * std::array<char, 128> d3;
+ * bytes_transferred = sock.receive(asio::buffer(d3));
+ *
+ * boost::array<char, 128> d4;
+ * bytes_transferred = sock.receive(asio::buffer(d4)); @endcode
+ *
+ * In all three cases above, the buffers created are exactly 128 bytes long.
+ * Note that a vector is @e never automatically resized when creating or using
+ * a buffer. The buffer size is determined using the vector's <tt>size()</tt>
+ * member function, and not its capacity.
+ *
+ * @par Accessing Buffer Contents
+ *
+ * The contents of a buffer may be accessed using the @c data() and @c size()
+ * member functions:
+ *
+ * @code asio::mutable_buffer b1 = ...;
+ * std::size_t s1 = b1.size();
+ * unsigned char* p1 = static_cast<unsigned char*>(b1.data());
+ *
+ * asio::const_buffer b2 = ...;
+ * std::size_t s2 = b2.size();
+ * const void* p2 = b2.data(); @endcode
+ *
+ * The @c data() member function permits violations of type safety, so
+ * uses of it in application code should be carefully considered.
+ *
+ * For convenience, a @ref buffer_size function is provided that works with
+ * both buffers and buffer sequences (that is, types meeting the
+ * ConstBufferSequence or MutableBufferSequence type requirements). In this
+ * case, the function returns the total size of all buffers in the sequence.
+ *
+ * @par Buffer Copying
+ *
+ * The @ref buffer_copy function may be used to copy raw bytes between
+ * individual buffers and buffer sequences.
+*
+ * In particular, when used with the @ref buffer_size function, the @ref
+ * buffer_copy function can be used to linearise a sequence of buffers. For
+ * example:
+ *
+ * @code vector<const_buffer> buffers = ...;
+ *
+ * vector<unsigned char> data(asio::buffer_size(buffers));
+ * asio::buffer_copy(asio::buffer(data), buffers); @endcode
+ *
+ * Note that @ref buffer_copy is implemented in terms of @c memcpy, and
+ * consequently it cannot be used to copy between overlapping memory regions.
+ *
+ * @par Buffer Invalidation
+ *
+ * A buffer object does not have any ownership of the memory it refers to. It
+ * is the responsibility of the application to ensure the memory region remains
+ * valid until it is no longer required for an I/O operation. When the memory
+ * is no longer available, the buffer is said to have been invalidated.
+ *
+ * For the asio::buffer overloads that accept an argument of type
+ * std::vector, the buffer objects returned are invalidated by any vector
+ * operation that also invalidates all references, pointers and iterators
+ * referring to the elements in the sequence (C++ Std, 23.2.4)
+ *
+ * For the asio::buffer overloads that accept an argument of type
+ * std::basic_string, the buffer objects returned are invalidated according to
+ * the rules defined for invalidation of references, pointers and iterators
+ * referring to elements of the sequence (C++ Std, 21.3).
+ *
+ * @par Buffer Arithmetic
+ *
+ * Buffer objects may be manipulated using simple arithmetic in a safe way
+ * which helps prevent buffer overruns. Consider an array initialised as
+ * follows:
+ *
+ * @code boost::array<char, 6> a = { 'a', 'b', 'c', 'd', 'e' }; @endcode
+ *
+ * A buffer object @c b1 created using:
+ *
+ * @code b1 = asio::buffer(a); @endcode
+ *
+ * represents the entire array, <tt>{ 'a', 'b', 'c', 'd', 'e' }</tt>. An
+ * optional second argument to the asio::buffer function may be used to
+ * limit the size, in bytes, of the buffer:
+ *
+ * @code b2 = asio::buffer(a, 3); @endcode
+ *
+ * such that @c b2 represents the data <tt>{ 'a', 'b', 'c' }</tt>. Even if the
+ * size argument exceeds the actual size of the array, the size of the buffer
+ * object created will be limited to the array size.
+ *
+ * An offset may be applied to an existing buffer to create a new one:
+ *
+ * @code b3 = b1 + 2; @endcode
+ *
+ * where @c b3 will set to represent <tt>{ 'c', 'd', 'e' }</tt>. If the offset
+ * exceeds the size of the existing buffer, the newly created buffer will be
+ * empty.
+ *
+ * Both an offset and size may be specified to create a buffer that corresponds
+ * to a specific range of bytes within an existing buffer:
+ *
+ * @code b4 = asio::buffer(b1 + 1, 3); @endcode
+ *
+ * so that @c b4 will refer to the bytes <tt>{ 'b', 'c', 'd' }</tt>.
+ *
+ * @par Buffers and Scatter-Gather I/O
+ *
+ * To read or write using multiple buffers (i.e. scatter-gather I/O), multiple
+ * buffer objects may be assigned into a container that supports the
+ * MutableBufferSequence (for read) or ConstBufferSequence (for write) concepts:
+ *
+ * @code
+ * char d1[128];
+ * std::vector<char> d2(128);
+ * boost::array<char, 128> d3;
+ *
+ * boost::array<mutable_buffer, 3> bufs1 = {
+ *   asio::buffer(d1),
+ *   asio::buffer(d2),
+ *   asio::buffer(d3) };
+ * bytes_transferred = sock.receive(bufs1);
+ *
+ * std::vector<const_buffer> bufs2;
+ * bufs2.push_back(asio::buffer(d1));
+ * bufs2.push_back(asio::buffer(d2));
+ * bufs2.push_back(asio::buffer(d3));
+ * bytes_transferred = sock.send(bufs2); @endcode
+ */
+/*@{*/
+
+#if defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+# define ASIO_MUTABLE_BUFFER mutable_buffer
+# define ASIO_CONST_BUFFER const_buffer
+#else // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+# define ASIO_MUTABLE_BUFFER mutable_buffers_1
+# define ASIO_CONST_BUFFER const_buffers_1
+#endif // defined(ASIO_NO_DEPRECATED) || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer from an existing buffer.
+/**
+ * @returns <tt>mutable_buffer(b)</tt>.
+ */
+inline ASIO_MUTABLE_BUFFER buffer(
+    const mutable_buffer& b) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(b);
+}
+
+/// Create a new modifiable buffer from an existing buffer.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     b.data(),
+ *     min(b.size(), max_size_in_bytes)); @endcode
+ */
+inline ASIO_MUTABLE_BUFFER buffer(const mutable_buffer& b,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(
+      mutable_buffer(b.data(),
+        b.size() < max_size_in_bytes
+        ? b.size() : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+        , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+        ));
+}
+
+/// Create a new non-modifiable buffer from an existing buffer.
+/**
+ * @returns <tt>const_buffer(b)</tt>.
+ */
+inline ASIO_CONST_BUFFER buffer(
+    const const_buffer& b) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(b);
+}
+
+/// Create a new non-modifiable buffer from an existing buffer.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     b.data(),
+ *     min(b.size(), max_size_in_bytes)); @endcode
+ */
+inline ASIO_CONST_BUFFER buffer(const const_buffer& b,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(b.data(),
+      b.size() < max_size_in_bytes
+      ? b.size() : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , b.get_debug_check()
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that represents the given memory range.
+/**
+ * @returns <tt>mutable_buffer(data, size_in_bytes)</tt>.
+ */
+inline ASIO_MUTABLE_BUFFER buffer(void* data,
+    std::size_t size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data, size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given memory range.
+/**
+ * @returns <tt>const_buffer(data, size_in_bytes)</tt>.
+ */
+inline ASIO_CONST_BUFFER buffer(const void* data,
+    std::size_t size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data, size_in_bytes);
+}
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     static_cast<void*>(data),
+ *     N * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(PodType (&data)[N]) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data, N * sizeof(PodType));
+}
+ 
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     static_cast<void*>(data),
+ *     min(N * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(PodType (&data)[N],
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data,
+      N * sizeof(PodType) < max_size_in_bytes
+      ? N * sizeof(PodType) : max_size_in_bytes);
+}
+ 
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     static_cast<const void*>(data),
+ *     N * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    const PodType (&data)[N]) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data, N * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     static_cast<const void*>(data),
+ *     min(N * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(const PodType (&data)[N],
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data,
+      N * sizeof(PodType) < max_size_in_bytes
+      ? N * sizeof(PodType) : max_size_in_bytes);
+}
+
+#if defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+// Borland C++ and Sun Studio think the overloads:
+//
+//   unspecified buffer(boost::array<PodType, N>& array ...);
+//
+// and
+//
+//   unspecified buffer(boost::array<const PodType, N>& array ...);
+//
+// are ambiguous. This will be worked around by using a buffer_types traits
+// class that contains typedefs for the appropriate buffer and container
+// classes, based on whether PodType is const or non-const.
+
+namespace detail {
+
+template <bool IsConst>
+struct buffer_types_base;
+
+template <>
+struct buffer_types_base<false>
+{
+  typedef mutable_buffer buffer_type;
+  typedef ASIO_MUTABLE_BUFFER container_type;
+};
+
+template <>
+struct buffer_types_base<true>
+{
+  typedef const_buffer buffer_type;
+  typedef ASIO_CONST_BUFFER container_type;
+};
+
+template <typename PodType>
+struct buffer_types
+  : public buffer_types_base<is_const<PodType>::value>
+{
+};
+
+} // namespace detail
+
+template <typename PodType, std::size_t N>
+inline typename detail::buffer_types<PodType>::container_type
+buffer(boost::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  typedef typename asio::detail::buffer_types<PodType>::buffer_type
+    buffer_type;
+  typedef typename asio::detail::buffer_types<PodType>::container_type
+    container_type;
+  return container_type(
+      buffer_type(data.c_array(), data.size() * sizeof(PodType)));
+}
+
+template <typename PodType, std::size_t N>
+inline typename detail::buffer_types<PodType>::container_type
+buffer(boost::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  typedef typename asio::detail::buffer_types<PodType>::buffer_type
+    buffer_type;
+  typedef typename asio::detail::buffer_types<PodType>::container_type
+    container_type;
+  return container_type(
+      buffer_type(data.c_array(),
+        data.size() * sizeof(PodType) < max_size_in_bytes
+        ? data.size() * sizeof(PodType) : max_size_in_bytes));
+}
+
+#else // defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(
+    boost::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(
+      data.c_array(), data.size() * sizeof(PodType));
+}
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(boost::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.c_array(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    boost::array<const PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(boost::array<const PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+#endif // defined(ASIO_ENABLE_ARRAY_BUFFER_WORKAROUND)
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    const boost::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(const boost::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+#if defined(ASIO_HAS_STD_ARRAY) || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new modifiable buffer that represents the given POD array.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_MUTABLE_BUFFER buffer(std::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    std::array<const PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(std::array<const PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     data.size() * sizeof(PodType)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(
+    const std::array<PodType, N>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(PodType));
+}
+
+/// Create a new non-modifiable buffer that represents the given POD array.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ */
+template <typename PodType, std::size_t N>
+inline ASIO_CONST_BUFFER buffer(const std::array<PodType, N>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes);
+}
+
+#endif // defined(ASIO_HAS_STD_ARRAY) || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer that represents the given POD vector.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     data.size() * sizeof(PodType)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::vector<PodType, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(
+      data.size() ? &data[0] : 0, data.size() * sizeof(PodType)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that represents the given POD vector.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(std::vector<PodType, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given POD vector.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     data.size() * sizeof(PodType)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::vector<PodType, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(
+      data.size() ? &data[0] : 0, data.size() * sizeof(PodType)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given POD vector.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(PodType), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any vector operation that would also
+ * invalidate iterators.
+ */
+template <typename PodType, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::vector<PodType, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(PodType) < max_size_in_bytes
+      ? data.size() * sizeof(PodType) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::vector<PodType, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that represents the given string.
+/**
+ * @returns <tt>mutable_buffer(data.size() ? &data[0] : 0,
+ * data.size() * sizeof(Elem))</tt>.
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::basic_string<Elem, Traits, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new modifiable buffer that represents the given string.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(Elem), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_MUTABLE_BUFFER buffer(
+    std::basic_string<Elem, Traits, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_MUTABLE_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem) < max_size_in_bytes
+      ? data.size() * sizeof(Elem) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given string.
+/**
+ * @returns <tt>const_buffer(data.data(), data.size() * sizeof(Elem))</tt>.
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::basic_string<Elem, Traits, Allocator>& data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(), data.size() * sizeof(Elem)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given string.
+/**
+ * @returns A const_buffer value equivalent to:
+ * @code const_buffer(
+ *     data.data(),
+ *     min(data.size() * sizeof(Elem), max_size_in_bytes)); @endcode
+ *
+ * @note The buffer is invalidated by any non-const operation called on the
+ * given string object.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline ASIO_CONST_BUFFER buffer(
+    const std::basic_string<Elem, Traits, Allocator>& data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.data(),
+      data.size() * sizeof(Elem) < max_size_in_bytes
+      ? data.size() * sizeof(Elem) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename std::basic_string<Elem, Traits, Allocator>::const_iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+#if defined(ASIO_HAS_STRING_VIEW) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Create a new modifiable buffer that represents the given string_view.
+/**
+ * @returns <tt>mutable_buffer(data.size() ? &data[0] : 0,
+ * data.size() * sizeof(Elem))</tt>.
+ */
+template <typename Elem, typename Traits>
+inline ASIO_CONST_BUFFER buffer(
+    basic_string_view<Elem, Traits> data) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem)
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename basic_string_view<Elem, Traits>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+/// Create a new non-modifiable buffer that represents the given string.
+/**
+ * @returns A mutable_buffer value equivalent to:
+ * @code mutable_buffer(
+ *     data.size() ? &data[0] : 0,
+ *     min(data.size() * sizeof(Elem), max_size_in_bytes)); @endcode
+ */
+template <typename Elem, typename Traits>
+inline ASIO_CONST_BUFFER buffer(
+    basic_string_view<Elem, Traits> data,
+    std::size_t max_size_in_bytes) ASIO_NOEXCEPT
+{
+  return ASIO_CONST_BUFFER(data.size() ? &data[0] : 0,
+      data.size() * sizeof(Elem) < max_size_in_bytes
+      ? data.size() * sizeof(Elem) : max_size_in_bytes
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+      , detail::buffer_debug_check<
+          typename basic_string_view<Elem, Traits>::iterator
+        >(data.begin())
+#endif // ASIO_ENABLE_BUFFER_DEBUGGING
+      );
+}
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
+/*@}*/
+
+/// Adapt a basic_string to the DynamicBuffer requirements.
+/**
+ * Requires that <tt>sizeof(Elem) == 1</tt>.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+class dynamic_string_buffer
+{
+public:
+  /// The type used to represent the input sequence as a list of buffers.
+  typedef ASIO_CONST_BUFFER const_buffers_type;
+
+  /// The type used to represent the output sequence as a list of buffers.
+  typedef ASIO_MUTABLE_BUFFER mutable_buffers_type;
+
+  /// Construct a dynamic buffer from a string.
+  /**
+   * @param s The string to be used as backing storage for the dynamic buffer.
+   * Any existing data in the string is treated as the dynamic buffer's input
+   * sequence. The object stores a reference to the string and the user is
+   * responsible for ensuring that the string object remains valid until the
+   * dynamic_string_buffer object is destroyed.
+   *
+   * @param maximum_size Specifies a maximum size for the buffer, in bytes.
+   */
+  explicit dynamic_string_buffer(std::basic_string<Elem, Traits, Allocator>& s,
+      std::size_t maximum_size =
+        (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+    : string_(s),
+      size_(string_.size()),
+      max_size_(maximum_size)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move construct a dynamic buffer.
+  dynamic_string_buffer(dynamic_string_buffer&& other) ASIO_NOEXCEPT
+    : string_(other.string_),
+      size_(other.size_),
+      max_size_(other.max_size_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get the size of the input sequence.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Get the maximum size of the dynamic buffer.
+  /**
+   * @returns The allowed maximum of the sum of the sizes of the input sequence
+   * and output sequence.
+   */
+  std::size_t max_size() const ASIO_NOEXCEPT
+  {
+    return max_size_;
+  }
+
+  /// Get the current capacity of the dynamic buffer.
+  /**
+   * @returns The current total capacity of the buffer, i.e. for both the input
+   * sequence and output sequence.
+   */
+  std::size_t capacity() const ASIO_NOEXCEPT
+  {
+    return string_.capacity();
+  }
+
+  /// Get a list of buffers that represents the input sequence.
+  /**
+   * @returns An object of type @c const_buffers_type that satisfies
+   * ConstBufferSequence requirements, representing the basic_string memory in
+   * input sequence.
+   *
+   * @note The returned object is invalidated by any @c dynamic_string_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  const_buffers_type data() const ASIO_NOEXCEPT
+  {
+    return const_buffers_type(asio::buffer(string_, size_));
+  }
+
+  /// Get a list of buffers that represents the output sequence, with the given
+  /// size.
+  /**
+   * Ensures that the output sequence can accommodate @c n bytes, resizing the
+   * basic_string object as necessary.
+   *
+   * @returns An object of type @c mutable_buffers_type that satisfies
+   * MutableBufferSequence requirements, representing basic_string memory
+   * at the start of the output sequence of size @c n.
+   *
+   * @throws std::length_error If <tt>size() + n > max_size()</tt>.
+   *
+   * @note The returned object is invalidated by any @c dynamic_string_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  mutable_buffers_type prepare(std::size_t n)
+  {
+    if (size () > max_size() || max_size() - size() < n)
+    {
+      std::length_error ex("dynamic_string_buffer too long");
+      asio::detail::throw_exception(ex);
+    }
+
+    string_.resize(size_ + n);
+
+    return asio::buffer(asio::buffer(string_) + size_, n);
+  }
+
+  /// Move bytes from the output sequence to the input sequence.
+  /**
+   * @param n The number of bytes to append from the start of the output
+   * sequence to the end of the input sequence. The remainder of the output
+   * sequence is discarded.
+   *
+   * Requires a preceding call <tt>prepare(x)</tt> where <tt>x >= n</tt>, and
+   * no intervening operations that modify the input or output sequence.
+   *
+   * @note If @c n is greater than the size of the output sequence, the entire
+   * output sequence is moved to the input sequence and no error is issued.
+   */
+  void commit(std::size_t n)
+  {
+    size_ += (std::min)(n, string_.size() - size_);
+    string_.resize(size_);
+  }
+
+  /// Remove characters from the input sequence.
+  /**
+   * Removes @c n characters from the beginning of the input sequence.
+   *
+   * @note If @c n is greater than the size of the input sequence, the entire
+   * input sequence is consumed and no error is issued.
+   */
+  void consume(std::size_t n)
+  {
+    std::size_t consume_length = (std::min)(n, size_);
+    string_.erase(0, consume_length);
+    size_ -= consume_length;
+  }
+
+private:
+  std::basic_string<Elem, Traits, Allocator>& string_;
+  std::size_t size_;
+  const std::size_t max_size_;
+};
+
+/// Adapt a vector to the DynamicBuffer requirements.
+/**
+ * Requires that <tt>sizeof(Elem) == 1</tt>.
+ */
+template <typename Elem, typename Allocator>
+class dynamic_vector_buffer
+{
+public:
+  /// The type used to represent the input sequence as a list of buffers.
+  typedef ASIO_CONST_BUFFER const_buffers_type;
+
+  /// The type used to represent the output sequence as a list of buffers.
+  typedef ASIO_MUTABLE_BUFFER mutable_buffers_type;
+
+  /// Construct a dynamic buffer from a string.
+  /**
+   * @param v The vector to be used as backing storage for the dynamic buffer.
+   * Any existing data in the vector is treated as the dynamic buffer's input
+   * sequence. The object stores a reference to the vector and the user is
+   * responsible for ensuring that the vector object remains valid until the
+   * dynamic_vector_buffer object is destroyed.
+   *
+   * @param maximum_size Specifies a maximum size for the buffer, in bytes.
+   */
+  explicit dynamic_vector_buffer(std::vector<Elem, Allocator>& v,
+      std::size_t maximum_size =
+        (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+    : vector_(v),
+      size_(vector_.size()),
+      max_size_(maximum_size)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move construct a dynamic buffer.
+  dynamic_vector_buffer(dynamic_vector_buffer&& other) ASIO_NOEXCEPT
+    : vector_(other.vector_),
+      size_(other.size_),
+      max_size_(other.max_size_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get the size of the input sequence.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return size_;
+  }
+
+  /// Get the maximum size of the dynamic buffer.
+  /**
+   * @returns The allowed maximum of the sum of the sizes of the input sequence
+   * and output sequence.
+   */
+  std::size_t max_size() const ASIO_NOEXCEPT
+  {
+    return max_size_;
+  }
+
+  /// Get the current capacity of the dynamic buffer.
+  /**
+   * @returns The current total capacity of the buffer, i.e. for both the input
+   * sequence and output sequence.
+   */
+  std::size_t capacity() const ASIO_NOEXCEPT
+  {
+    return vector_.capacity();
+  }
+
+  /// Get a list of buffers that represents the input sequence.
+  /**
+   * @returns An object of type @c const_buffers_type that satisfies
+   * ConstBufferSequence requirements, representing the basic_string memory in
+   * input sequence.
+   *
+   * @note The returned object is invalidated by any @c dynamic_vector_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  const_buffers_type data() const ASIO_NOEXCEPT
+  {
+    return const_buffers_type(asio::buffer(vector_, size_));
+  }
+
+  /// Get a list of buffers that represents the output sequence, with the given
+  /// size.
+  /**
+   * Ensures that the output sequence can accommodate @c n bytes, resizing the
+   * basic_string object as necessary.
+   *
+   * @returns An object of type @c mutable_buffers_type that satisfies
+   * MutableBufferSequence requirements, representing basic_string memory
+   * at the start of the output sequence of size @c n.
+   *
+   * @throws std::length_error If <tt>size() + n > max_size()</tt>.
+   *
+   * @note The returned object is invalidated by any @c dynamic_vector_buffer
+   * or @c basic_string member function that modifies the input sequence or
+   * output sequence.
+   */
+  mutable_buffers_type prepare(std::size_t n)
+  {
+    if (size () > max_size() || max_size() - size() < n)
+    {
+      std::length_error ex("dynamic_vector_buffer too long");
+      asio::detail::throw_exception(ex);
+    }
+
+    vector_.resize(size_ + n);
+
+    return asio::buffer(asio::buffer(vector_) + size_, n);
+  }
+
+  /// Move bytes from the output sequence to the input sequence.
+  /**
+   * @param n The number of bytes to append from the start of the output
+   * sequence to the end of the input sequence. The remainder of the output
+   * sequence is discarded.
+   *
+   * Requires a preceding call <tt>prepare(x)</tt> where <tt>x >= n</tt>, and
+   * no intervening operations that modify the input or output sequence.
+   *
+   * @note If @c n is greater than the size of the output sequence, the entire
+   * output sequence is moved to the input sequence and no error is issued.
+   */
+  void commit(std::size_t n)
+  {
+    size_ += (std::min)(n, vector_.size() - size_);
+    vector_.resize(size_);
+  }
+
+  /// Remove characters from the input sequence.
+  /**
+   * Removes @c n characters from the beginning of the input sequence.
+   *
+   * @note If @c n is greater than the size of the input sequence, the entire
+   * input sequence is consumed and no error is issued.
+   */
+  void consume(std::size_t n)
+  {
+    std::size_t consume_length = (std::min)(n, size_);
+    vector_.erase(vector_.begin(), vector_.begin() + consume_length);
+    size_ -= consume_length;
+  }
+
+private:
+  std::vector<Elem, Allocator>& vector_;
+  std::size_t size_;
+  const std::size_t max_size_;
+};
+
+/** @defgroup dynamic_buffer asio::dynamic_buffer
+ *
+ * @brief The asio::dynamic_buffer function is used to create a
+ * dynamically resized buffer from a @c std::basic_string or @c std::vector.
+ */
+/*@{*/
+
+/// Create a new dynamic buffer that represents the given string.
+/**
+ * @returns <tt>dynamic_string_buffer<Elem, Traits, Allocator>(data)</tt>.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline dynamic_string_buffer<Elem, Traits, Allocator> dynamic_buffer(
+    std::basic_string<Elem, Traits, Allocator>& data) ASIO_NOEXCEPT
+{
+  return dynamic_string_buffer<Elem, Traits, Allocator>(data);
+}
+
+/// Create a new dynamic buffer that represents the given string.
+/**
+ * @returns <tt>dynamic_string_buffer<Elem, Traits, Allocator>(data,
+ * max_size)</tt>.
+ */
+template <typename Elem, typename Traits, typename Allocator>
+inline dynamic_string_buffer<Elem, Traits, Allocator> dynamic_buffer(
+    std::basic_string<Elem, Traits, Allocator>& data,
+    std::size_t max_size) ASIO_NOEXCEPT
+{
+  return dynamic_string_buffer<Elem, Traits, Allocator>(data, max_size);
+}
+
+/// Create a new dynamic buffer that represents the given vector.
+/**
+ * @returns <tt>dynamic_vector_buffer<Elem, Allocator>(data)</tt>.
+ */
+template <typename Elem, typename Allocator>
+inline dynamic_vector_buffer<Elem, Allocator> dynamic_buffer(
+    std::vector<Elem, Allocator>& data) ASIO_NOEXCEPT
+{
+  return dynamic_vector_buffer<Elem, Allocator>(data);
+}
+
+/// Create a new dynamic buffer that represents the given vector.
+/**
+ * @returns <tt>dynamic_vector_buffer<Elem, Allocator>(data, max_size)</tt>.
+ */
+template <typename Elem, typename Allocator>
+inline dynamic_vector_buffer<Elem, Allocator> dynamic_buffer(
+    std::vector<Elem, Allocator>& data,
+    std::size_t max_size) ASIO_NOEXCEPT
+{
+  return dynamic_vector_buffer<Elem, Allocator>(data, max_size);
+}
+
+/*@}*/
+
+/** @defgroup buffer_copy asio::buffer_copy
+ *
+ * @brief The asio::buffer_copy function is used to copy bytes from a
+ * source buffer (or buffer sequence) to a target buffer (or buffer sequence).
+ *
+ * The @c buffer_copy function is available in two forms:
+ *
+ * @li A 2-argument form: @c buffer_copy(target, source)
+ *
+ * @li A 3-argument form: @c buffer_copy(target, source, max_bytes_to_copy)
+ *
+ * Both forms return the number of bytes actually copied. The number of bytes
+ * copied is the lesser of:
+ *
+ * @li @c buffer_size(target)
+ *
+ * @li @c buffer_size(source)
+ *
+ * @li @c If specified, @c max_bytes_to_copy.
+ *
+ * This prevents buffer overflow, regardless of the buffer sizes used in the
+ * copy operation.
+ *
+ * Note that @ref buffer_copy is implemented in terms of @c memcpy, and
+ * consequently it cannot be used to copy between overlapping memory regions.
+ */
+/*@{*/
+
+namespace detail {
+
+inline std::size_t buffer_copy_1(const mutable_buffer& target,
+    const const_buffer& source)
+{
+  using namespace std; // For memcpy.
+  std::size_t target_size = target.size();
+  std::size_t source_size = source.size();
+  std::size_t n = target_size < source_size ? target_size : source_size;
+  if (n > 0)
+    memcpy(target.data(), source.data(), n);
+  return n;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+inline std::size_t buffer_copy(one_buffer, one_buffer,
+    TargetIterator target_begin, TargetIterator,
+    SourceIterator source_begin, SourceIterator) ASIO_NOEXCEPT
+{
+  return (buffer_copy_1)(*target_begin, *source_begin);
+}
+
+template <typename TargetIterator, typename SourceIterator>
+inline std::size_t buffer_copy(one_buffer, one_buffer,
+    TargetIterator target_begin, TargetIterator,
+    SourceIterator source_begin, SourceIterator,
+    std::size_t max_bytes_to_copy) ASIO_NOEXCEPT
+{
+  return (buffer_copy_1)(*target_begin,
+      asio::buffer(*source_begin, max_bytes_to_copy));
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(one_buffer, multiple_buffers,
+    TargetIterator target_begin, TargetIterator,
+    SourceIterator source_begin, SourceIterator source_end,
+    std::size_t max_bytes_to_copy
+      = (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+  SourceIterator source_iter = source_begin;
+
+  for (mutable_buffer target_buffer(
+        asio::buffer(*target_begin, max_bytes_to_copy));
+      target_buffer.size() && source_iter != source_end; ++source_iter)
+  {
+    const_buffer source_buffer(*source_iter);
+    std::size_t bytes_copied = (buffer_copy_1)(target_buffer, source_buffer);
+    total_bytes_copied += bytes_copied;
+    target_buffer += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(multiple_buffers, one_buffer,
+    TargetIterator target_begin, TargetIterator target_end,
+    SourceIterator source_begin, SourceIterator,
+    std::size_t max_bytes_to_copy
+      = (std::numeric_limits<std::size_t>::max)()) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+  TargetIterator target_iter = target_begin;
+
+  for (const_buffer source_buffer(
+        asio::buffer(*source_begin, max_bytes_to_copy));
+      source_buffer.size() && target_iter != target_end; ++target_iter)
+  {
+    mutable_buffer target_buffer(*target_iter);
+    std::size_t bytes_copied = (buffer_copy_1)(target_buffer, source_buffer);
+    total_bytes_copied += bytes_copied;
+    source_buffer += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(multiple_buffers, multiple_buffers,
+    TargetIterator target_begin, TargetIterator target_end,
+    SourceIterator source_begin, SourceIterator source_end) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+
+  TargetIterator target_iter = target_begin;
+  std::size_t target_buffer_offset = 0;
+
+  SourceIterator source_iter = source_begin;
+  std::size_t source_buffer_offset = 0;
+
+  while (target_iter != target_end && source_iter != source_end)
+  {
+    mutable_buffer target_buffer =
+      mutable_buffer(*target_iter) + target_buffer_offset;
+
+    const_buffer source_buffer =
+      const_buffer(*source_iter) + source_buffer_offset;
+
+    std::size_t bytes_copied = (buffer_copy_1)(target_buffer, source_buffer);
+    total_bytes_copied += bytes_copied;
+
+    if (bytes_copied == target_buffer.size())
+    {
+      ++target_iter;
+      target_buffer_offset = 0;
+    }
+    else
+      target_buffer_offset += bytes_copied;
+
+    if (bytes_copied == source_buffer.size())
+    {
+      ++source_iter;
+      source_buffer_offset = 0;
+    }
+    else
+      source_buffer_offset += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+template <typename TargetIterator, typename SourceIterator>
+std::size_t buffer_copy(multiple_buffers, multiple_buffers,
+    TargetIterator target_begin, TargetIterator target_end,
+    SourceIterator source_begin, SourceIterator source_end,
+    std::size_t max_bytes_to_copy) ASIO_NOEXCEPT
+{
+  std::size_t total_bytes_copied = 0;
+
+  TargetIterator target_iter = target_begin;
+  std::size_t target_buffer_offset = 0;
+
+  SourceIterator source_iter = source_begin;
+  std::size_t source_buffer_offset = 0;
+
+  while (total_bytes_copied != max_bytes_to_copy
+      && target_iter != target_end && source_iter != source_end)
+  {
+    mutable_buffer target_buffer =
+      mutable_buffer(*target_iter) + target_buffer_offset;
+
+    const_buffer source_buffer =
+      const_buffer(*source_iter) + source_buffer_offset;
+
+    std::size_t bytes_copied = (buffer_copy_1)(
+        target_buffer, asio::buffer(source_buffer,
+          max_bytes_to_copy - total_bytes_copied));
+    total_bytes_copied += bytes_copied;
+
+    if (bytes_copied == target_buffer.size())
+    {
+      ++target_iter;
+      target_buffer_offset = 0;
+    }
+    else
+      target_buffer_offset += bytes_copied;
+
+    if (bytes_copied == source_buffer.size())
+    {
+      ++source_iter;
+      source_buffer_offset = 0;
+    }
+    else
+      source_buffer_offset += bytes_copied;
+  }
+
+  return total_bytes_copied;
+}
+
+} // namespace detail
+
+/// Copies bytes from a source buffer sequence to a target buffer sequence.
+/**
+ * @param target A modifiable buffer sequence representing the memory regions to
+ * which the bytes will be copied.
+ *
+ * @param source A non-modifiable buffer sequence representing the memory
+ * regions from which the bytes will be copied.
+ *
+ * @returns The number of bytes copied.
+ *
+ * @note The number of bytes copied is the lesser of:
+ *
+ * @li @c buffer_size(target)
+ *
+ * @li @c buffer_size(source)
+ *
+ * This function is implemented in terms of @c memcpy, and consequently it
+ * cannot be used to copy between overlapping memory regions.
+ */
+template <typename MutableBufferSequence, typename ConstBufferSequence>
+inline std::size_t buffer_copy(const MutableBufferSequence& target,
+    const ConstBufferSequence& source) ASIO_NOEXCEPT
+{
+  return detail::buffer_copy(
+      detail::buffer_sequence_cardinality<MutableBufferSequence>(),
+      detail::buffer_sequence_cardinality<ConstBufferSequence>(),
+      asio::buffer_sequence_begin(target),
+      asio::buffer_sequence_end(target),
+      asio::buffer_sequence_begin(source),
+      asio::buffer_sequence_end(source));
+}
+
+/// Copies a limited number of bytes from a source buffer sequence to a target
+/// buffer sequence.
+/**
+ * @param target A modifiable buffer sequence representing the memory regions to
+ * which the bytes will be copied.
+ *
+ * @param source A non-modifiable buffer sequence representing the memory
+ * regions from which the bytes will be copied.
+ *
+ * @param max_bytes_to_copy The maximum number of bytes to be copied.
+ *
+ * @returns The number of bytes copied.
+ *
+ * @note The number of bytes copied is the lesser of:
+ *
+ * @li @c buffer_size(target)
+ *
+ * @li @c buffer_size(source)
+ *
+ * @li @c max_bytes_to_copy
+ *
+ * This function is implemented in terms of @c memcpy, and consequently it
+ * cannot be used to copy between overlapping memory regions.
+ */
+template <typename MutableBufferSequence, typename ConstBufferSequence>
+inline std::size_t buffer_copy(const MutableBufferSequence& target,
+    const ConstBufferSequence& source,
+    std::size_t max_bytes_to_copy) ASIO_NOEXCEPT
+{
+  return detail::buffer_copy(
+      detail::buffer_sequence_cardinality<MutableBufferSequence>(),
+      detail::buffer_sequence_cardinality<ConstBufferSequence>(),
+      asio::buffer_sequence_begin(target),
+      asio::buffer_sequence_end(target),
+      asio::buffer_sequence_begin(source),
+      asio::buffer_sequence_end(source), max_bytes_to_copy);
+}
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+#include "asio/detail/is_buffer_sequence.hpp"
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Trait to determine whether a type satisfies the MutableBufferSequence
+/// requirements.
+template <typename T>
+struct is_mutable_buffer_sequence
+#if defined(GENERATING_DOCUMENTATION)
+  : integral_constant<bool, automatically_determined>
+#else // defined(GENERATING_DOCUMENTATION)
+  : asio::detail::is_buffer_sequence<T, mutable_buffer>
+#endif // defined(GENERATING_DOCUMENTATION)
+{
+};
+
+/// Trait to determine whether a type satisfies the ConstBufferSequence
+/// requirements.
+template <typename T>
+struct is_const_buffer_sequence
+#if defined(GENERATING_DOCUMENTATION)
+  : integral_constant<bool, automatically_determined>
+#else // defined(GENERATING_DOCUMENTATION)
+  : asio::detail::is_buffer_sequence<T, const_buffer>
+#endif // defined(GENERATING_DOCUMENTATION)
+{
+};
+
+/// Trait to determine whether a type satisfies the DynamicBuffer requirements.
+template <typename T>
+struct is_dynamic_buffer
+#if defined(GENERATING_DOCUMENTATION)
+  : integral_constant<bool, automatically_determined>
+#else // defined(GENERATING_DOCUMENTATION)
+  : asio::detail::is_dynamic_buffer<T>
+#endif // defined(GENERATING_DOCUMENTATION)
+{
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BUFFER_HPP
diff --git a/subprojects/asio/include/asio/buffered_read_stream.hpp b/subprojects/asio/include/asio/buffered_read_stream.hpp
new file mode 100644
index 000000000..c3e7f0b57
--- /dev/null
+++ b/subprojects/asio/include/asio/buffered_read_stream.hpp
@@ -0,0 +1,257 @@
+//
+// buffered_read_stream.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFERED_READ_STREAM_HPP
+#define ASIO_BUFFERED_READ_STREAM_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/buffered_read_stream_fwd.hpp"
+#include "asio/buffer.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_resize_guard.hpp"
+#include "asio/detail/buffered_stream_storage.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Adds buffering to the read-related operations of a stream.
+/**
+ * The buffered_read_stream class template can be used to add buffering to the
+ * synchronous and asynchronous read operations of a stream.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+template <typename Stream>
+class buffered_read_stream
+  : private noncopyable
+{
+public:
+  /// The type of the next layer.
+  typedef typename remove_reference<Stream>::type next_layer_type;
+
+  /// The type of the lowest layer.
+  typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
+
+  /// The type of the executor associated with the object.
+  typedef typename lowest_layer_type::executor_type executor_type;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// The default buffer size.
+  static const std::size_t default_buffer_size = implementation_defined;
+#else
+  ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024);
+#endif
+
+  /// Construct, passing the specified argument to initialise the next layer.
+  template <typename Arg>
+  explicit buffered_read_stream(Arg& a)
+    : next_layer_(a),
+      storage_(default_buffer_size)
+  {
+  }
+
+  /// Construct, passing the specified argument to initialise the next layer.
+  template <typename Arg>
+  buffered_read_stream(Arg& a, std::size_t buffer_size)
+    : next_layer_(a),
+      storage_(buffer_size)
+  {
+  }
+
+  /// Get a reference to the next layer.
+  next_layer_type& next_layer()
+  {
+    return next_layer_;
+  }
+
+  /// Get a reference to the lowest layer.
+  lowest_layer_type& lowest_layer()
+  {
+    return next_layer_.lowest_layer();
+  }
+
+  /// Get a const reference to the lowest layer.
+  const lowest_layer_type& lowest_layer() const
+  {
+    return next_layer_.lowest_layer();
+  }
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return next_layer_.lowest_layer().get_executor();
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_context()
+  {
+    return next_layer_.get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_service()
+  {
+    return next_layer_.get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Close the stream.
+  void close()
+  {
+    next_layer_.close();
+  }
+
+  /// Close the stream.
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    next_layer_.close(ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Write the given data to the stream. Returns the number of bytes written.
+  /// Throws an exception on failure.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    return next_layer_.write_some(buffers);
+  }
+
+  /// Write the given data to the stream. Returns the number of bytes written,
+  /// or 0 if an error occurred.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return next_layer_.write_some(buffers, ec);
+  }
+
+  /// Start an asynchronous write. The data being written must be valid for the
+  /// lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    return next_layer_.async_write_some(buffers,
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+  }
+
+  /// Fill the buffer with some data. Returns the number of bytes placed in the
+  /// buffer as a result of the operation. Throws an exception on failure.
+  std::size_t fill();
+
+  /// Fill the buffer with some data. Returns the number of bytes placed in the
+  /// buffer as a result of the operation, or 0 if an error occurred.
+  std::size_t fill(asio::error_code& ec);
+
+  /// Start an asynchronous fill.
+  template <typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_fill(ASIO_MOVE_ARG(ReadHandler) handler);
+
+  /// Read some data from the stream. Returns the number of bytes read. Throws
+  /// an exception on failure.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers);
+
+  /// Read some data from the stream. Returns the number of bytes read or 0 if
+  /// an error occurred.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec);
+
+  /// Start an asynchronous read. The buffer into which the data will be read
+  /// must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler);
+
+  /// Peek at the incoming data on the stream. Returns the number of bytes read.
+  /// Throws an exception on failure.
+  template <typename MutableBufferSequence>
+  std::size_t peek(const MutableBufferSequence& buffers);
+
+  /// Peek at the incoming data on the stream. Returns the number of bytes read,
+  /// or 0 if an error occurred.
+  template <typename MutableBufferSequence>
+  std::size_t peek(const MutableBufferSequence& buffers,
+      asio::error_code& ec);
+
+  /// Determine the amount of data that may be read without blocking.
+  std::size_t in_avail()
+  {
+    return storage_.size();
+  }
+
+  /// Determine the amount of data that may be read without blocking.
+  std::size_t in_avail(asio::error_code& ec)
+  {
+    ec = asio::error_code();
+    return storage_.size();
+  }
+
+private:
+  /// Copy data out of the internal buffer to the specified target buffer.
+  /// Returns the number of bytes copied.
+  template <typename MutableBufferSequence>
+  std::size_t copy(const MutableBufferSequence& buffers)
+  {
+    std::size_t bytes_copied = asio::buffer_copy(
+        buffers, storage_.data(), storage_.size());
+    storage_.consume(bytes_copied);
+    return bytes_copied;
+  }
+
+  /// Copy data from the internal buffer to the specified target buffer, without
+  /// removing the data from the internal buffer. Returns the number of bytes
+  /// copied.
+  template <typename MutableBufferSequence>
+  std::size_t peek_copy(const MutableBufferSequence& buffers)
+  {
+    return asio::buffer_copy(buffers, storage_.data(), storage_.size());
+  }
+
+  /// The next layer.
+  Stream next_layer_;
+
+  // The data in the buffer.
+  detail::buffered_stream_storage storage_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/buffered_read_stream.hpp"
+
+#endif // ASIO_BUFFERED_READ_STREAM_HPP
diff --git a/subprojects/asio/include/asio/buffered_read_stream_fwd.hpp b/subprojects/asio/include/asio/buffered_read_stream_fwd.hpp
new file mode 100644
index 000000000..334b88a5c
--- /dev/null
+++ b/subprojects/asio/include/asio/buffered_read_stream_fwd.hpp
@@ -0,0 +1,25 @@
+//
+// buffered_read_stream_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFERED_READ_STREAM_FWD_HPP
+#define ASIO_BUFFERED_READ_STREAM_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+namespace asio {
+
+template <typename Stream>
+class buffered_read_stream;
+
+} // namespace asio
+
+#endif // ASIO_BUFFERED_READ_STREAM_FWD_HPP
diff --git a/subprojects/asio/include/asio/buffered_stream.hpp b/subprojects/asio/include/asio/buffered_stream.hpp
new file mode 100644
index 000000000..8014fa4dd
--- /dev/null
+++ b/subprojects/asio/include/asio/buffered_stream.hpp
@@ -0,0 +1,278 @@
+//
+// buffered_stream.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFERED_STREAM_HPP
+#define ASIO_BUFFERED_STREAM_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/buffered_read_stream.hpp"
+#include "asio/buffered_write_stream.hpp"
+#include "asio/buffered_stream_fwd.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Adds buffering to the read- and write-related operations of a stream.
+/**
+ * The buffered_stream class template can be used to add buffering to the
+ * synchronous and asynchronous read and write operations of a stream.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+template <typename Stream>
+class buffered_stream
+  : private noncopyable
+{
+public:
+  /// The type of the next layer.
+  typedef typename remove_reference<Stream>::type next_layer_type;
+
+  /// The type of the lowest layer.
+  typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
+
+  /// The type of the executor associated with the object.
+  typedef typename lowest_layer_type::executor_type executor_type;
+
+  /// Construct, passing the specified argument to initialise the next layer.
+  template <typename Arg>
+  explicit buffered_stream(Arg& a)
+    : inner_stream_impl_(a),
+      stream_impl_(inner_stream_impl_)
+  {
+  }
+
+  /// Construct, passing the specified argument to initialise the next layer.
+  template <typename Arg>
+  explicit buffered_stream(Arg& a, std::size_t read_buffer_size,
+      std::size_t write_buffer_size)
+    : inner_stream_impl_(a, write_buffer_size),
+      stream_impl_(inner_stream_impl_, read_buffer_size)
+  {
+  }
+
+  /// Get a reference to the next layer.
+  next_layer_type& next_layer()
+  {
+    return stream_impl_.next_layer().next_layer();
+  }
+
+  /// Get a reference to the lowest layer.
+  lowest_layer_type& lowest_layer()
+  {
+    return stream_impl_.lowest_layer();
+  }
+
+  /// Get a const reference to the lowest layer.
+  const lowest_layer_type& lowest_layer() const
+  {
+    return stream_impl_.lowest_layer();
+  }
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return stream_impl_.lowest_layer().get_executor();
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_context()
+  {
+    return stream_impl_.get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_service()
+  {
+    return stream_impl_.get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Close the stream.
+  void close()
+  {
+    stream_impl_.close();
+  }
+
+  /// Close the stream.
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    stream_impl_.close(ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Flush all data from the buffer to the next layer. Returns the number of
+  /// bytes written to the next layer on the last write operation. Throws an
+  /// exception on failure.
+  std::size_t flush()
+  {
+    return stream_impl_.next_layer().flush();
+  }
+
+  /// Flush all data from the buffer to the next layer. Returns the number of
+  /// bytes written to the next layer on the last write operation, or 0 if an
+  /// error occurred.
+  std::size_t flush(asio::error_code& ec)
+  {
+    return stream_impl_.next_layer().flush(ec);
+  }
+
+  /// Start an asynchronous flush.
+  template <typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_flush(ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    return stream_impl_.next_layer().async_flush(
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+  }
+
+  /// Write the given data to the stream. Returns the number of bytes written.
+  /// Throws an exception on failure.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    return stream_impl_.write_some(buffers);
+  }
+
+  /// Write the given data to the stream. Returns the number of bytes written,
+  /// or 0 if an error occurred.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return stream_impl_.write_some(buffers, ec);
+  }
+
+  /// Start an asynchronous write. The data being written must be valid for the
+  /// lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    return stream_impl_.async_write_some(buffers,
+        ASIO_MOVE_CAST(WriteHandler)(handler));
+  }
+
+  /// Fill the buffer with some data. Returns the number of bytes placed in the
+  /// buffer as a result of the operation. Throws an exception on failure.
+  std::size_t fill()
+  {
+    return stream_impl_.fill();
+  }
+
+  /// Fill the buffer with some data. Returns the number of bytes placed in the
+  /// buffer as a result of the operation, or 0 if an error occurred.
+  std::size_t fill(asio::error_code& ec)
+  {
+    return stream_impl_.fill(ec);
+  }
+
+  /// Start an asynchronous fill.
+  template <typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_fill(ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    return stream_impl_.async_fill(ASIO_MOVE_CAST(ReadHandler)(handler));
+  }
+
+  /// Read some data from the stream. Returns the number of bytes read. Throws
+  /// an exception on failure.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    return stream_impl_.read_some(buffers);
+  }
+
+  /// Read some data from the stream. Returns the number of bytes read or 0 if
+  /// an error occurred.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return stream_impl_.read_some(buffers, ec);
+  }
+
+  /// Start an asynchronous read. The buffer into which the data will be read
+  /// must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    return stream_impl_.async_read_some(buffers,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+  }
+
+  /// Peek at the incoming data on the stream. Returns the number of bytes read.
+  /// Throws an exception on failure.
+  template <typename MutableBufferSequence>
+  std::size_t peek(const MutableBufferSequence& buffers)
+  {
+    return stream_impl_.peek(buffers);
+  }
+
+  /// Peek at the incoming data on the stream. Returns the number of bytes read,
+  /// or 0 if an error occurred.
+  template <typename MutableBufferSequence>
+  std::size_t peek(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return stream_impl_.peek(buffers, ec);
+  }
+
+  /// Determine the amount of data that may be read without blocking.
+  std::size_t in_avail()
+  {
+    return stream_impl_.in_avail();
+  }
+
+  /// Determine the amount of data that may be read without blocking.
+  std::size_t in_avail(asio::error_code& ec)
+  {
+    return stream_impl_.in_avail(ec);
+  }
+
+private:
+  // The buffered write stream.
+  typedef buffered_write_stream<Stream> write_stream_type;
+  write_stream_type inner_stream_impl_;
+
+  // The buffered read stream.
+  typedef buffered_read_stream<write_stream_type&> read_stream_type;
+  read_stream_type stream_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BUFFERED_STREAM_HPP
diff --git a/subprojects/asio/include/asio/buffered_stream_fwd.hpp b/subprojects/asio/include/asio/buffered_stream_fwd.hpp
new file mode 100644
index 000000000..3492979d2
--- /dev/null
+++ b/subprojects/asio/include/asio/buffered_stream_fwd.hpp
@@ -0,0 +1,25 @@
+//
+// buffered_stream_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFERED_STREAM_FWD_HPP
+#define ASIO_BUFFERED_STREAM_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+namespace asio {
+
+template <typename Stream>
+class buffered_stream;
+
+} // namespace asio
+
+#endif // ASIO_BUFFERED_STREAM_FWD_HPP
diff --git a/subprojects/asio/include/asio/buffered_write_stream.hpp b/subprojects/asio/include/asio/buffered_write_stream.hpp
new file mode 100644
index 000000000..aac33d38f
--- /dev/null
+++ b/subprojects/asio/include/asio/buffered_write_stream.hpp
@@ -0,0 +1,249 @@
+//
+// buffered_write_stream.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFERED_WRITE_STREAM_HPP
+#define ASIO_BUFFERED_WRITE_STREAM_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/buffered_write_stream_fwd.hpp"
+#include "asio/buffer.hpp"
+#include "asio/completion_condition.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffered_stream_storage.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/write.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Adds buffering to the write-related operations of a stream.
+/**
+ * The buffered_write_stream class template can be used to add buffering to the
+ * synchronous and asynchronous write operations of a stream.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+template <typename Stream>
+class buffered_write_stream
+  : private noncopyable
+{
+public:
+  /// The type of the next layer.
+  typedef typename remove_reference<Stream>::type next_layer_type;
+
+  /// The type of the lowest layer.
+  typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
+
+  /// The type of the executor associated with the object.
+  typedef typename lowest_layer_type::executor_type executor_type;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// The default buffer size.
+  static const std::size_t default_buffer_size = implementation_defined;
+#else
+  ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024);
+#endif
+
+  /// Construct, passing the specified argument to initialise the next layer.
+  template <typename Arg>
+  explicit buffered_write_stream(Arg& a)
+    : next_layer_(a),
+      storage_(default_buffer_size)
+  {
+  }
+
+  /// Construct, passing the specified argument to initialise the next layer.
+  template <typename Arg>
+  buffered_write_stream(Arg& a, std::size_t buffer_size)
+    : next_layer_(a),
+      storage_(buffer_size)
+  {
+  }
+
+  /// Get a reference to the next layer.
+  next_layer_type& next_layer()
+  {
+    return next_layer_;
+  }
+
+  /// Get a reference to the lowest layer.
+  lowest_layer_type& lowest_layer()
+  {
+    return next_layer_.lowest_layer();
+  }
+
+  /// Get a const reference to the lowest layer.
+  const lowest_layer_type& lowest_layer() const
+  {
+    return next_layer_.lowest_layer();
+  }
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return next_layer_.lowest_layer().get_executor();
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_context()
+  {
+    return next_layer_.get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_service()
+  {
+    return next_layer_.get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Close the stream.
+  void close()
+  {
+    next_layer_.close();
+  }
+
+  /// Close the stream.
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    next_layer_.close(ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Flush all data from the buffer to the next layer. Returns the number of
+  /// bytes written to the next layer on the last write operation. Throws an
+  /// exception on failure.
+  std::size_t flush();
+
+  /// Flush all data from the buffer to the next layer. Returns the number of
+  /// bytes written to the next layer on the last write operation, or 0 if an
+  /// error occurred.
+  std::size_t flush(asio::error_code& ec);
+
+  /// Start an asynchronous flush.
+  template <typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_flush(ASIO_MOVE_ARG(WriteHandler) handler);
+
+  /// Write the given data to the stream. Returns the number of bytes written.
+  /// Throws an exception on failure.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers);
+
+  /// Write the given data to the stream. Returns the number of bytes written,
+  /// or 0 if an error occurred and the error handler did not throw.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec);
+
+  /// Start an asynchronous write. The data being written must be valid for the
+  /// lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler);
+
+  /// Read some data from the stream. Returns the number of bytes read. Throws
+  /// an exception on failure.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    return next_layer_.read_some(buffers);
+  }
+
+  /// Read some data from the stream. Returns the number of bytes read or 0 if
+  /// an error occurred.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return next_layer_.read_some(buffers, ec);
+  }
+
+  /// Start an asynchronous read. The buffer into which the data will be read
+  /// must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    return next_layer_.async_read_some(buffers,
+        ASIO_MOVE_CAST(ReadHandler)(handler));
+  }
+
+  /// Peek at the incoming data on the stream. Returns the number of bytes read.
+  /// Throws an exception on failure.
+  template <typename MutableBufferSequence>
+  std::size_t peek(const MutableBufferSequence& buffers)
+  {
+    return next_layer_.peek(buffers);
+  }
+
+  /// Peek at the incoming data on the stream. Returns the number of bytes read,
+  /// or 0 if an error occurred.
+  template <typename MutableBufferSequence>
+  std::size_t peek(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return next_layer_.peek(buffers, ec);
+  }
+
+  /// Determine the amount of data that may be read without blocking.
+  std::size_t in_avail()
+  {
+    return next_layer_.in_avail();
+  }
+
+  /// Determine the amount of data that may be read without blocking.
+  std::size_t in_avail(asio::error_code& ec)
+  {
+    return next_layer_.in_avail(ec);
+  }
+
+private:
+  /// Copy data into the internal buffer from the specified source buffer.
+  /// Returns the number of bytes copied.
+  template <typename ConstBufferSequence>
+  std::size_t copy(const ConstBufferSequence& buffers);
+
+  /// The next layer.
+  Stream next_layer_;
+
+  // The data in the buffer.
+  detail::buffered_stream_storage storage_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/buffered_write_stream.hpp"
+
+#endif // ASIO_BUFFERED_WRITE_STREAM_HPP
diff --git a/subprojects/asio/include/asio/buffered_write_stream_fwd.hpp b/subprojects/asio/include/asio/buffered_write_stream_fwd.hpp
new file mode 100644
index 000000000..6ef54ba0d
--- /dev/null
+++ b/subprojects/asio/include/asio/buffered_write_stream_fwd.hpp
@@ -0,0 +1,25 @@
+//
+// buffered_write_stream_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFERED_WRITE_STREAM_FWD_HPP
+#define ASIO_BUFFERED_WRITE_STREAM_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+namespace asio {
+
+template <typename Stream>
+class buffered_write_stream;
+
+} // namespace asio
+
+#endif // ASIO_BUFFERED_WRITE_STREAM_FWD_HPP
diff --git a/subprojects/asio/include/asio/buffers_iterator.hpp b/subprojects/asio/include/asio/buffers_iterator.hpp
new file mode 100644
index 000000000..f5c9d4c35
--- /dev/null
+++ b/subprojects/asio/include/asio/buffers_iterator.hpp
@@ -0,0 +1,521 @@
+//
+// buffers_iterator.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_BUFFERS_ITERATOR_HPP
+#define ASIO_BUFFERS_ITERATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <iterator>
+#include "asio/buffer.hpp"
+#include "asio/detail/assert.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  template <bool IsMutable>
+  struct buffers_iterator_types_helper;
+
+  template <>
+  struct buffers_iterator_types_helper<false>
+  {
+    typedef const_buffer buffer_type;
+    template <typename ByteType>
+    struct byte_type
+    {
+      typedef typename add_const<ByteType>::type type;
+    };
+  };
+
+  template <>
+  struct buffers_iterator_types_helper<true>
+  {
+    typedef mutable_buffer buffer_type;
+    template <typename ByteType>
+    struct byte_type
+    {
+      typedef ByteType type;
+    };
+  };
+
+  template <typename BufferSequence, typename ByteType>
+  struct buffers_iterator_types
+  {
+    enum
+    {
+      is_mutable = is_convertible<
+          typename BufferSequence::value_type,
+          mutable_buffer>::value
+    };
+    typedef buffers_iterator_types_helper<is_mutable> helper;
+    typedef typename helper::buffer_type buffer_type;
+    typedef typename helper::template byte_type<ByteType>::type byte_type;
+    typedef typename BufferSequence::const_iterator const_iterator;
+  };
+
+  template <typename ByteType>
+  struct buffers_iterator_types<mutable_buffer, ByteType>
+  {
+    typedef mutable_buffer buffer_type;
+    typedef ByteType byte_type;
+    typedef const mutable_buffer* const_iterator;
+  };
+
+  template <typename ByteType>
+  struct buffers_iterator_types<const_buffer, ByteType>
+  {
+    typedef const_buffer buffer_type;
+    typedef typename add_const<ByteType>::type byte_type;
+    typedef const const_buffer* const_iterator;
+  };
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+  template <typename ByteType>
+  struct buffers_iterator_types<mutable_buffers_1, ByteType>
+  {
+    typedef mutable_buffer buffer_type;
+    typedef ByteType byte_type;
+    typedef const mutable_buffer* const_iterator;
+  };
+
+  template <typename ByteType>
+  struct buffers_iterator_types<const_buffers_1, ByteType>
+  {
+    typedef const_buffer buffer_type;
+    typedef typename add_const<ByteType>::type byte_type;
+    typedef const const_buffer* const_iterator;
+  };
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+}
+
+/// A random access iterator over the bytes in a buffer sequence.
+template <typename BufferSequence, typename ByteType = char>
+class buffers_iterator
+{
+private:
+  typedef typename detail::buffers_iterator_types<
+      BufferSequence, ByteType>::buffer_type buffer_type;
+
+  typedef typename detail::buffers_iterator_types<BufferSequence,
+          ByteType>::const_iterator buffer_sequence_iterator_type;
+
+public:
+  /// The type used for the distance between two iterators.
+  typedef std::ptrdiff_t difference_type;
+
+  /// The type of the value pointed to by the iterator.
+  typedef ByteType value_type;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// The type of the result of applying operator->() to the iterator.
+  /**
+   * If the buffer sequence stores buffer objects that are convertible to
+   * mutable_buffer, this is a pointer to a non-const ByteType. Otherwise, a
+   * pointer to a const ByteType.
+   */
+  typedef const_or_non_const_ByteType* pointer;
+#else // defined(GENERATING_DOCUMENTATION)
+  typedef typename detail::buffers_iterator_types<
+      BufferSequence, ByteType>::byte_type* pointer;
+#endif // defined(GENERATING_DOCUMENTATION)
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// The type of the result of applying operator*() to the iterator.
+  /**
+   * If the buffer sequence stores buffer objects that are convertible to
+   * mutable_buffer, this is a reference to a non-const ByteType. Otherwise, a
+   * reference to a const ByteType.
+   */
+  typedef const_or_non_const_ByteType& reference;
+#else // defined(GENERATING_DOCUMENTATION)
+  typedef typename detail::buffers_iterator_types<
+      BufferSequence, ByteType>::byte_type& reference;
+#endif // defined(GENERATING_DOCUMENTATION)
+
+  /// The iterator category.
+  typedef std::random_access_iterator_tag iterator_category;
+
+  /// Default constructor. Creates an iterator in an undefined state.
+  buffers_iterator()
+    : current_buffer_(),
+      current_buffer_position_(0),
+      begin_(),
+      current_(),
+      end_(),
+      position_(0)
+  {
+  }
+
+  /// Construct an iterator representing the beginning of the buffers' data.
+  static buffers_iterator begin(const BufferSequence& buffers)
+#if defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3)
+    __attribute__ ((__noinline__))
+#endif // defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3)
+  {
+    buffers_iterator new_iter;
+    new_iter.begin_ = asio::buffer_sequence_begin(buffers);
+    new_iter.current_ = asio::buffer_sequence_begin(buffers);
+    new_iter.end_ = asio::buffer_sequence_end(buffers);
+    while (new_iter.current_ != new_iter.end_)
+    {
+      new_iter.current_buffer_ = *new_iter.current_;
+      if (new_iter.current_buffer_.size() > 0)
+        break;
+      ++new_iter.current_;
+    }
+    return new_iter;
+  }
+
+  /// Construct an iterator representing the end of the buffers' data.
+  static buffers_iterator end(const BufferSequence& buffers)
+#if defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3)
+    __attribute__ ((__noinline__))
+#endif // defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 3)
+  {
+    buffers_iterator new_iter;
+    new_iter.begin_ = asio::buffer_sequence_begin(buffers);
+    new_iter.current_ = asio::buffer_sequence_begin(buffers);
+    new_iter.end_ = asio::buffer_sequence_end(buffers);
+    while (new_iter.current_ != new_iter.end_)
+    {
+      buffer_type buffer = *new_iter.current_;
+      new_iter.position_ += buffer.size();
+      ++new_iter.current_;
+    }
+    return new_iter;
+  }
+
+  /// Dereference an iterator.
+  reference operator*() const
+  {
+    return dereference();
+  }
+
+  /// Dereference an iterator.
+  pointer operator->() const
+  {
+    return &dereference();
+  }
+
+  /// Access an individual element.
+  reference operator[](std::ptrdiff_t difference) const
+  {
+    buffers_iterator tmp(*this);
+    tmp.advance(difference);
+    return *tmp;
+  }
+
+  /// Increment operator (prefix).
+  buffers_iterator& operator++()
+  {
+    increment();
+    return *this;
+  }
+
+  /// Increment operator (postfix).
+  buffers_iterator operator++(int)
+  {
+    buffers_iterator tmp(*this);
+    ++*this;
+    return tmp;
+  }
+
+  /// Decrement operator (prefix).
+  buffers_iterator& operator--()
+  {
+    decrement();
+    return *this;
+  }
+
+  /// Decrement operator (postfix).
+  buffers_iterator operator--(int)
+  {
+    buffers_iterator tmp(*this);
+    --*this;
+    return tmp;
+  }
+
+  /// Addition operator.
+  buffers_iterator& operator+=(std::ptrdiff_t difference)
+  {
+    advance(difference);
+    return *this;
+  }
+
+  /// Subtraction operator.
+  buffers_iterator& operator-=(std::ptrdiff_t difference)
+  {
+    advance(-difference);
+    return *this;
+  }
+
+  /// Addition operator.
+  friend buffers_iterator operator+(const buffers_iterator& iter,
+      std::ptrdiff_t difference)
+  {
+    buffers_iterator tmp(iter);
+    tmp.advance(difference);
+    return tmp;
+  }
+
+  /// Addition operator.
+  friend buffers_iterator operator+(std::ptrdiff_t difference,
+      const buffers_iterator& iter)
+  {
+    buffers_iterator tmp(iter);
+    tmp.advance(difference);
+    return tmp;
+  }
+
+  /// Subtraction operator.
+  friend buffers_iterator operator-(const buffers_iterator& iter,
+      std::ptrdiff_t difference)
+  {
+    buffers_iterator tmp(iter);
+    tmp.advance(-difference);
+    return tmp;
+  }
+
+  /// Subtraction operator.
+  friend std::ptrdiff_t operator-(const buffers_iterator& a,
+      const buffers_iterator& b)
+  {
+    return b.distance_to(a);
+  }
+
+  /// Test two iterators for equality.
+  friend bool operator==(const buffers_iterator& a, const buffers_iterator& b)
+  {
+    return a.equal(b);
+  }
+
+  /// Test two iterators for inequality.
+  friend bool operator!=(const buffers_iterator& a, const buffers_iterator& b)
+  {
+    return !a.equal(b);
+  }
+
+  /// Compare two iterators.
+  friend bool operator<(const buffers_iterator& a, const buffers_iterator& b)
+  {
+    return a.distance_to(b) > 0;
+  }
+
+  /// Compare two iterators.
+  friend bool operator<=(const buffers_iterator& a, const buffers_iterator& b)
+  {
+    return !(b < a);
+  }
+
+  /// Compare two iterators.
+  friend bool operator>(const buffers_iterator& a, const buffers_iterator& b)
+  {
+    return b < a;
+  }
+
+  /// Compare two iterators.
+  friend bool operator>=(const buffers_iterator& a, const buffers_iterator& b)
+  {
+    return !(a < b);
+  }
+
+private:
+  // Dereference the iterator.
+  reference dereference() const
+  {
+    return static_cast<pointer>(
+        current_buffer_.data())[current_buffer_position_];
+  }
+
+  // Compare two iterators for equality.
+  bool equal(const buffers_iterator& other) const
+  {
+    return position_ == other.position_;
+  }
+
+  // Increment the iterator.
+  void increment()
+  {
+    ASIO_ASSERT(current_ != end_ && "iterator out of bounds");
+    ++position_;
+
+    // Check if the increment can be satisfied by the current buffer.
+    ++current_buffer_position_;
+    if (current_buffer_position_ != current_buffer_.size())
+      return;
+
+    // Find the next non-empty buffer.
+    ++current_;
+    current_buffer_position_ = 0;
+    while (current_ != end_)
+    {
+      current_buffer_ = *current_;
+      if (current_buffer_.size() > 0)
+        return;
+      ++current_;
+    }
+  }
+
+  // Decrement the iterator.
+  void decrement()
+  {
+    ASIO_ASSERT(position_ > 0 && "iterator out of bounds");
+    --position_;
+
+    // Check if the decrement can be satisfied by the current buffer.
+    if (current_buffer_position_ != 0)
+    {
+      --current_buffer_position_;
+      return;
+    }
+
+    // Find the previous non-empty buffer.
+    buffer_sequence_iterator_type iter = current_;
+    while (iter != begin_)
+    {
+      --iter;
+      buffer_type buffer = *iter;
+      std::size_t buffer_size = buffer.size();
+      if (buffer_size > 0)
+      {
+        current_ = iter;
+        current_buffer_ = buffer;
+        current_buffer_position_ = buffer_size - 1;
+        return;
+      }
+    }
+  }
+
+  // Advance the iterator by the specified distance.
+  void advance(std::ptrdiff_t n)
+  {
+    if (n > 0)
+    {
+      ASIO_ASSERT(current_ != end_ && "iterator out of bounds");
+      for (;;)
+      {
+        std::ptrdiff_t current_buffer_balance
+          = current_buffer_.size() - current_buffer_position_;
+
+        // Check if the advance can be satisfied by the current buffer.
+        if (current_buffer_balance > n)
+        {
+          position_ += n;
+          current_buffer_position_ += n;
+          return;
+        }
+
+        // Update position.
+        n -= current_buffer_balance;
+        position_ += current_buffer_balance;
+
+        // Move to next buffer. If it is empty then it will be skipped on the
+        // next iteration of this loop.
+        if (++current_ == end_)
+        {
+          ASIO_ASSERT(n == 0 && "iterator out of bounds");
+          current_buffer_ = buffer_type();
+          current_buffer_position_ = 0;
+          return;
+        }
+        current_buffer_ = *current_;
+        current_buffer_position_ = 0;
+      }
+    }
+    else if (n < 0)
+    {
+      std::size_t abs_n = -n;
+      ASIO_ASSERT(position_ >= abs_n && "iterator out of bounds");
+      for (;;)
+      {
+        // Check if the advance can be satisfied by the current buffer.
+        if (current_buffer_position_ >= abs_n)
+        {
+          position_ -= abs_n;
+          current_buffer_position_ -= abs_n;
+          return;
+        }
+
+        // Update position.
+        abs_n -= current_buffer_position_;
+        position_ -= current_buffer_position_;
+
+        // Check if we've reached the beginning of the buffers.
+        if (current_ == begin_)
+        {
+          ASIO_ASSERT(abs_n == 0 && "iterator out of bounds");
+          current_buffer_position_ = 0;
+          return;
+        }
+
+        // Find the previous non-empty buffer.
+        buffer_sequence_iterator_type iter = current_;
+        while (iter != begin_)
+        {
+          --iter;
+          buffer_type buffer = *iter;
+          std::size_t buffer_size = buffer.size();
+          if (buffer_size > 0)
+          {
+            current_ = iter;
+            current_buffer_ = buffer;
+            current_buffer_position_ = buffer_size;
+            break;
+          }
+        }
+      }
+    }
+  }
+
+  // Determine the distance between two iterators.
+  std::ptrdiff_t distance_to(const buffers_iterator& other) const
+  {
+    return other.position_ - position_;
+  }
+
+  buffer_type current_buffer_;
+  std::size_t current_buffer_position_;
+  buffer_sequence_iterator_type begin_;
+  buffer_sequence_iterator_type current_;
+  buffer_sequence_iterator_type end_;
+  std::size_t position_;
+};
+
+/// Construct an iterator representing the beginning of the buffers' data.
+template <typename BufferSequence>
+inline buffers_iterator<BufferSequence> buffers_begin(
+    const BufferSequence& buffers)
+{
+  return buffers_iterator<BufferSequence>::begin(buffers);
+}
+
+/// Construct an iterator representing the end of the buffers' data.
+template <typename BufferSequence>
+inline buffers_iterator<BufferSequence> buffers_end(
+    const BufferSequence& buffers)
+{
+  return buffers_iterator<BufferSequence>::end(buffers);
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_BUFFERS_ITERATOR_HPP
diff --git a/subprojects/asio/include/asio/completion_condition.hpp b/subprojects/asio/include/asio/completion_condition.hpp
new file mode 100644
index 000000000..563f417d1
--- /dev/null
+++ b/subprojects/asio/include/asio/completion_condition.hpp
@@ -0,0 +1,218 @@
+//
+// completion_condition.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_COMPLETION_CONDITION_HPP
+#define ASIO_COMPLETION_CONDITION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail {
+
+// The default maximum number of bytes to transfer in a single operation.
+enum default_max_transfer_size_t { default_max_transfer_size = 65536 };
+
+// Adapt result of old-style completion conditions (which had a bool result
+// where true indicated that the operation was complete).
+inline std::size_t adapt_completion_condition_result(bool result)
+{
+  return result ? 0 : default_max_transfer_size;
+}
+
+// Adapt result of current completion conditions (which have a size_t result
+// where 0 means the operation is complete, and otherwise the result is the
+// maximum number of bytes to transfer on the next underlying operation).
+inline std::size_t adapt_completion_condition_result(std::size_t result)
+{
+  return result;
+}
+
+class transfer_all_t
+{
+public:
+  typedef std::size_t result_type;
+
+  template <typename Error>
+  std::size_t operator()(const Error& err, std::size_t)
+  {
+    return !!err ? 0 : default_max_transfer_size;
+  }
+};
+
+class transfer_at_least_t
+{
+public:
+  typedef std::size_t result_type;
+
+  explicit transfer_at_least_t(std::size_t minimum)
+    : minimum_(minimum)
+  {
+  }
+
+  template <typename Error>
+  std::size_t operator()(const Error& err, std::size_t bytes_transferred)
+  {
+    return (!!err || bytes_transferred >= minimum_)
+      ? 0 : default_max_transfer_size;
+  }
+
+private:
+  std::size_t minimum_;
+};
+
+class transfer_exactly_t
+{
+public:
+  typedef std::size_t result_type;
+
+  explicit transfer_exactly_t(std::size_t size)
+    : size_(size)
+  {
+  }
+
+  template <typename Error>
+  std::size_t operator()(const Error& err, std::size_t bytes_transferred)
+  {
+    return (!!err || bytes_transferred >= size_) ? 0 :
+      (size_ - bytes_transferred < default_max_transfer_size
+        ? size_ - bytes_transferred : std::size_t(default_max_transfer_size));
+  }
+
+private:
+  std::size_t size_;
+};
+
+} // namespace detail
+
+/**
+ * @defgroup completion_condition Completion Condition Function Objects
+ *
+ * Function objects used for determining when a read or write operation should
+ * complete.
+ */
+/*@{*/
+
+/// Return a completion condition function object that indicates that a read or
+/// write operation should continue until all of the data has been transferred,
+/// or until an error occurs.
+/**
+ * This function is used to create an object, of unspecified type, that meets
+ * CompletionCondition requirements.
+ *
+ * @par Example
+ * Reading until a buffer is full:
+ * @code
+ * boost::array<char, 128> buf;
+ * asio::error_code ec;
+ * std::size_t n = asio::read(
+ *     sock, asio::buffer(buf),
+ *     asio::transfer_all(), ec);
+ * if (ec)
+ * {
+ *   // An error occurred.
+ * }
+ * else
+ * {
+ *   // n == 128
+ * }
+ * @endcode
+ */
+#if defined(GENERATING_DOCUMENTATION)
+unspecified transfer_all();
+#else
+inline detail::transfer_all_t transfer_all()
+{
+  return detail::transfer_all_t();
+}
+#endif
+
+/// Return a completion condition function object that indicates that a read or
+/// write operation should continue until a minimum number of bytes has been
+/// transferred, or until an error occurs.
+/**
+ * This function is used to create an object, of unspecified type, that meets
+ * CompletionCondition requirements.
+ *
+ * @par Example
+ * Reading until a buffer is full or contains at least 64 bytes:
+ * @code
+ * boost::array<char, 128> buf;
+ * asio::error_code ec;
+ * std::size_t n = asio::read(
+ *     sock, asio::buffer(buf),
+ *     asio::transfer_at_least(64), ec);
+ * if (ec)
+ * {
+ *   // An error occurred.
+ * }
+ * else
+ * {
+ *   // n >= 64 && n <= 128
+ * }
+ * @endcode
+ */
+#if defined(GENERATING_DOCUMENTATION)
+unspecified transfer_at_least(std::size_t minimum);
+#else
+inline detail::transfer_at_least_t transfer_at_least(std::size_t minimum)
+{
+  return detail::transfer_at_least_t(minimum);
+}
+#endif
+
+/// Return a completion condition function object that indicates that a read or
+/// write operation should continue until an exact number of bytes has been
+/// transferred, or until an error occurs.
+/**
+ * This function is used to create an object, of unspecified type, that meets
+ * CompletionCondition requirements.
+ *
+ * @par Example
+ * Reading until a buffer is full or contains exactly 64 bytes:
+ * @code
+ * boost::array<char, 128> buf;
+ * asio::error_code ec;
+ * std::size_t n = asio::read(
+ *     sock, asio::buffer(buf),
+ *     asio::transfer_exactly(64), ec);
+ * if (ec)
+ * {
+ *   // An error occurred.
+ * }
+ * else
+ * {
+ *   // n == 64
+ * }
+ * @endcode
+ */
+#if defined(GENERATING_DOCUMENTATION)
+unspecified transfer_exactly(std::size_t size);
+#else
+inline detail::transfer_exactly_t transfer_exactly(std::size_t size)
+{
+  return detail::transfer_exactly_t(size);
+}
+#endif
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_COMPLETION_CONDITION_HPP
diff --git a/subprojects/asio/include/asio/connect.hpp b/subprojects/asio/include/asio/connect.hpp
new file mode 100644
index 000000000..89a9f35f9
--- /dev/null
+++ b/subprojects/asio/include/asio/connect.hpp
@@ -0,0 +1,1060 @@
+//
+// connect.hpp
+// ~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_CONNECT_HPP
+#define ASIO_CONNECT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/async_result.hpp"
+#include "asio/basic_socket.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  char (&has_iterator_helper(...))[2];
+
+  template <typename T>
+  char has_iterator_helper(T*, typename T::iterator* = 0);
+
+  template <typename T>
+  struct has_iterator_typedef
+  {
+    enum { value = (sizeof((has_iterator_helper)((T*)(0))) == 1) };
+  };
+} // namespace detail
+
+/// Type trait used to determine whether a type is an endpoint sequence that can
+/// be used with with @c connect and @c async_connect.
+template <typename T>
+struct is_endpoint_sequence
+{
+#if defined(GENERATING_DOCUMENTATION)
+  /// The value member is true if the type may be used as an endpoint sequence.
+  static const bool value;
+#else
+  enum
+  {
+    value = detail::has_iterator_typedef<T>::value
+  };
+#endif
+};
+
+/**
+ * @defgroup connect asio::connect
+ *
+ * @brief The @c connect function is a composed operation that establishes a
+ * socket connection by trying each endpoint in a sequence.
+ */
+/*@{*/
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param endpoints A sequence of endpoints.
+ *
+ * @returns The successfully connected endpoint.
+ *
+ * @throws asio::system_error Thrown on failure. If the sequence is
+ * empty, the associated @c error_code is asio::error::not_found.
+ * Otherwise, contains the error from the last connection attempt.
+ *
+ * @par Example
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::socket s(io_context);
+ * asio::connect(s, r.resolve(q)); @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename EndpointSequence>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type* = 0);
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param endpoints A sequence of endpoints.
+ *
+ * @param ec Set to indicate what error occurred, if any. If the sequence is
+ * empty, set to asio::error::not_found. Otherwise, contains the error
+ * from the last connection attempt.
+ *
+ * @returns On success, the successfully connected endpoint. Otherwise, a
+ * default-constructed endpoint.
+ *
+ * @par Example
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::socket s(io_context);
+ * asio::error_code ec;
+ * asio::connect(s, r.resolve(q), ec);
+ * if (ec)
+ * {
+ *   // An error occurred.
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename EndpointSequence>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, asio::error_code& ec,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type* = 0);
+
+#if !defined(ASIO_NO_DEPRECATED)
+/// (Deprecated: Use range overload.) Establishes a socket connection by trying
+/// each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @returns On success, an iterator denoting the successfully connected
+ * endpoint. Otherwise, the end iterator.
+ *
+ * @throws asio::system_error Thrown on failure. If the sequence is
+ * empty, the associated @c error_code is asio::error::not_found.
+ * Otherwise, contains the error from the last connection attempt.
+ *
+ * @note This overload assumes that a default constructed object of type @c
+ * Iterator represents the end of the sequence. This is a valid assumption for
+ * iterator types such as @c asio::ip::tcp::resolver::iterator.
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s, Iterator begin,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type* = 0);
+
+/// (Deprecated: Use range overload.) Establishes a socket connection by trying
+/// each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param ec Set to indicate what error occurred, if any. If the sequence is
+ * empty, set to asio::error::not_found. Otherwise, contains the error
+ * from the last connection attempt.
+ *
+ * @returns On success, an iterator denoting the successfully connected
+ * endpoint. Otherwise, the end iterator.
+ *
+ * @note This overload assumes that a default constructed object of type @c
+ * Iterator represents the end of the sequence. This is a valid assumption for
+ * iterator types such as @c asio::ip::tcp::resolver::iterator.
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, asio::error_code& ec,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type* = 0);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param end An iterator pointing to the end of a sequence of endpoints.
+ *
+ * @returns An iterator denoting the successfully connected endpoint.
+ *
+ * @throws asio::system_error Thrown on failure. If the sequence is
+ * empty, the associated @c error_code is asio::error::not_found.
+ * Otherwise, contains the error from the last connection attempt.
+ *
+ * @par Example
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::resolver::results_type e = r.resolve(q);
+ * tcp::socket s(io_context);
+ * asio::connect(s, e.begin(), e.end()); @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end);
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param end An iterator pointing to the end of a sequence of endpoints.
+ *
+ * @param ec Set to indicate what error occurred, if any. If the sequence is
+ * empty, set to asio::error::not_found. Otherwise, contains the error
+ * from the last connection attempt.
+ *
+ * @returns On success, an iterator denoting the successfully connected
+ * endpoint. Otherwise, the end iterator.
+ *
+ * @par Example
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::resolver::results_type e = r.resolve(q);
+ * tcp::socket s(io_context);
+ * asio::error_code ec;
+ * asio::connect(s, e.begin(), e.end(), ec);
+ * if (ec)
+ * {
+ *   // An error occurred.
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end, asio::error_code& ec);
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param endpoints A sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @returns The successfully connected endpoint.
+ *
+ * @throws asio::system_error Thrown on failure. If the sequence is
+ * empty, the associated @c error_code is asio::error::not_found.
+ * Otherwise, contains the error from the last connection attempt.
+ *
+ * @par Example
+ * The following connect condition function object can be used to output
+ * information about the individual connection attempts:
+ * @code struct my_connect_condition
+ * {
+ *   bool operator()(
+ *       const asio::error_code& ec,
+ *       const::tcp::endpoint& next)
+ *   {
+ *     if (ec) std::cout << "Error: " << ec.message() << std::endl;
+ *     std::cout << "Trying: " << next << std::endl;
+ *     return true;
+ *   }
+ * }; @endcode
+ * It would be used with the asio::connect function as follows:
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::socket s(io_context);
+ * tcp::endpoint e = asio::connect(s,
+ *     r.resolve(q), my_connect_condition());
+ * std::cout << "Connected to: " << e << std::endl; @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename ConnectCondition>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, ConnectCondition connect_condition,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type* = 0);
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param endpoints A sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @param ec Set to indicate what error occurred, if any. If the sequence is
+ * empty, set to asio::error::not_found. Otherwise, contains the error
+ * from the last connection attempt.
+ *
+ * @returns On success, the successfully connected endpoint. Otherwise, a
+ * default-constructed endpoint.
+ *
+ * @par Example
+ * The following connect condition function object can be used to output
+ * information about the individual connection attempts:
+ * @code struct my_connect_condition
+ * {
+ *   bool operator()(
+ *       const asio::error_code& ec,
+ *       const::tcp::endpoint& next)
+ *   {
+ *     if (ec) std::cout << "Error: " << ec.message() << std::endl;
+ *     std::cout << "Trying: " << next << std::endl;
+ *     return true;
+ *   }
+ * }; @endcode
+ * It would be used with the asio::connect function as follows:
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::socket s(io_context);
+ * asio::error_code ec;
+ * tcp::endpoint e = asio::connect(s,
+ *     r.resolve(q), my_connect_condition(), ec);
+ * if (ec)
+ * {
+ *   // An error occurred.
+ * }
+ * else
+ * {
+ *   std::cout << "Connected to: " << e << std::endl;
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename ConnectCondition>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, ConnectCondition connect_condition,
+    asio::error_code& ec,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type* = 0);
+
+#if !defined(ASIO_NO_DEPRECATED)
+/// (Deprecated: Use range overload.) Establishes a socket connection by trying
+/// each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @returns On success, an iterator denoting the successfully connected
+ * endpoint. Otherwise, the end iterator.
+ *
+ * @throws asio::system_error Thrown on failure. If the sequence is
+ * empty, the associated @c error_code is asio::error::not_found.
+ * Otherwise, contains the error from the last connection attempt.
+ *
+ * @note This overload assumes that a default constructed object of type @c
+ * Iterator represents the end of the sequence. This is a valid assumption for
+ * iterator types such as @c asio::ip::tcp::resolver::iterator.
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, ConnectCondition connect_condition,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type* = 0);
+
+/// (Deprecated: Use range overload.) Establishes a socket connection by trying
+/// each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @param ec Set to indicate what error occurred, if any. If the sequence is
+ * empty, set to asio::error::not_found. Otherwise, contains the error
+ * from the last connection attempt.
+ *
+ * @returns On success, an iterator denoting the successfully connected
+ * endpoint. Otherwise, the end iterator.
+ *
+ * @note This overload assumes that a default constructed object of type @c
+ * Iterator represents the end of the sequence. This is a valid assumption for
+ * iterator types such as @c asio::ip::tcp::resolver::iterator.
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s, Iterator begin,
+    ConnectCondition connect_condition, asio::error_code& ec,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type* = 0);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param end An iterator pointing to the end of a sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @returns An iterator denoting the successfully connected endpoint.
+ *
+ * @throws asio::system_error Thrown on failure. If the sequence is
+ * empty, the associated @c error_code is asio::error::not_found.
+ * Otherwise, contains the error from the last connection attempt.
+ *
+ * @par Example
+ * The following connect condition function object can be used to output
+ * information about the individual connection attempts:
+ * @code struct my_connect_condition
+ * {
+ *   bool operator()(
+ *       const asio::error_code& ec,
+ *       const::tcp::endpoint& next)
+ *   {
+ *     if (ec) std::cout << "Error: " << ec.message() << std::endl;
+ *     std::cout << "Trying: " << next << std::endl;
+ *     return true;
+ *   }
+ * }; @endcode
+ * It would be used with the asio::connect function as follows:
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::resolver::results_type e = r.resolve(q);
+ * tcp::socket s(io_context);
+ * tcp::resolver::results_type::iterator i = asio::connect(
+ *     s, e.begin(), e.end(), my_connect_condition());
+ * std::cout << "Connected to: " << i->endpoint() << std::endl; @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s, Iterator begin,
+    Iterator end, ConnectCondition connect_condition);
+
+/// Establishes a socket connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c connect member
+ * function, once for each endpoint in the sequence, until a connection is
+ * successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param end An iterator pointing to the end of a sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @param ec Set to indicate what error occurred, if any. If the sequence is
+ * empty, set to asio::error::not_found. Otherwise, contains the error
+ * from the last connection attempt.
+ *
+ * @returns On success, an iterator denoting the successfully connected
+ * endpoint. Otherwise, the end iterator.
+ *
+ * @par Example
+ * The following connect condition function object can be used to output
+ * information about the individual connection attempts:
+ * @code struct my_connect_condition
+ * {
+ *   bool operator()(
+ *       const asio::error_code& ec,
+ *       const::tcp::endpoint& next)
+ *   {
+ *     if (ec) std::cout << "Error: " << ec.message() << std::endl;
+ *     std::cout << "Trying: " << next << std::endl;
+ *     return true;
+ *   }
+ * }; @endcode
+ * It would be used with the asio::connect function as follows:
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::resolver::results_type e = r.resolve(q);
+ * tcp::socket s(io_context);
+ * asio::error_code ec;
+ * tcp::resolver::results_type::iterator i = asio::connect(
+ *     s, e.begin(), e.end(), my_connect_condition());
+ * if (ec)
+ * {
+ *   // An error occurred.
+ * }
+ * else
+ * {
+ *   std::cout << "Connected to: " << i->endpoint() << std::endl;
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end, ConnectCondition connect_condition,
+    asio::error_code& ec);
+
+/*@}*/
+
+/**
+ * @defgroup async_connect asio::async_connect
+ *
+ * @brief The @c async_connect function is a composed asynchronous operation
+ * that establishes a socket connection by trying each endpoint in a sequence.
+ */
+/*@{*/
+
+/// Asynchronously establishes a socket connection by trying each endpoint in a
+/// sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c async_connect
+ * member function, once for each endpoint in the sequence, until a connection
+ * is successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param endpoints A sequence of endpoints.
+ *
+ * @param handler The handler to be called when the connect operation
+ * completes. Copies will be made of the handler as required. The function
+ * signature of the handler must be:
+ * @code void handler(
+ *   // Result of operation. if the sequence is empty, set to
+ *   // asio::error::not_found. Otherwise, contains the
+ *   // error from the last connection attempt.
+ *   const asio::error_code& error,
+ *
+ *   // On success, the successfully connected endpoint.
+ *   // Otherwise, a default-constructed endpoint.
+ *   const typename Protocol::endpoint& endpoint
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation
+ * of the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::socket s(io_context);
+ *
+ * // ...
+ *
+ * r.async_resolve(q, resolve_handler);
+ *
+ * // ...
+ *
+ * void resolve_handler(
+ *     const asio::error_code& ec,
+ *     tcp::resolver::results_type results)
+ * {
+ *   if (!ec)
+ *   {
+ *     asio::async_connect(s, results, connect_handler);
+ *   }
+ * }
+ *
+ * // ...
+ *
+ * void connect_handler(
+ *     const asio::error_code& ec,
+ *     const tcp::endpoint& endpoint)
+ * {
+ *   // ...
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename RangeConnectHandler>
+ASIO_INITFN_RESULT_TYPE(RangeConnectHandler,
+    void (asio::error_code, typename Protocol::endpoint))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints,
+    ASIO_MOVE_ARG(RangeConnectHandler) handler,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type* = 0);
+
+#if !defined(ASIO_NO_DEPRECATED)
+/// (Deprecated: Use range overload.) Asynchronously establishes a socket
+/// connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c async_connect
+ * member function, once for each endpoint in the sequence, until a connection
+ * is successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param handler The handler to be called when the connect operation
+ * completes. Copies will be made of the handler as required. The function
+ * signature of the handler must be:
+ * @code void handler(
+ *   // Result of operation. if the sequence is empty, set to
+ *   // asio::error::not_found. Otherwise, contains the
+ *   // error from the last connection attempt.
+ *   const asio::error_code& error,
+ *
+ *   // On success, an iterator denoting the successfully
+ *   // connected endpoint. Otherwise, the end iterator.
+ *   Iterator iterator
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation
+ * of the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note This overload assumes that a default constructed object of type @c
+ * Iterator represents the end of the sequence. This is a valid assumption for
+ * iterator types such as @c asio::ip::tcp::resolver::iterator.
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename IteratorConnectHandler>
+ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, ASIO_MOVE_ARG(IteratorConnectHandler) handler,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type* = 0);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Asynchronously establishes a socket connection by trying each endpoint in a
+/// sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c async_connect
+ * member function, once for each endpoint in the sequence, until a connection
+ * is successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param end An iterator pointing to the end of a sequence of endpoints.
+ *
+ * @param handler The handler to be called when the connect operation
+ * completes. Copies will be made of the handler as required. The function
+ * signature of the handler must be:
+ * @code void handler(
+ *   // Result of operation. if the sequence is empty, set to
+ *   // asio::error::not_found. Otherwise, contains the
+ *   // error from the last connection attempt.
+ *   const asio::error_code& error,
+ *
+ *   // On success, an iterator denoting the successfully
+ *   // connected endpoint. Otherwise, the end iterator.
+ *   Iterator iterator
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation
+ * of the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * @code std::vector<tcp::endpoint> endpoints = ...;
+ * tcp::socket s(io_context);
+ * asio::async_connect(s,
+ *     endpoints.begin(), endpoints.end(),
+ *     connect_handler);
+ *
+ * // ...
+ *
+ * void connect_handler(
+ *     const asio::error_code& ec,
+ *     std::vector<tcp::endpoint>::iterator i)
+ * {
+ *   // ...
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename IteratorConnectHandler>
+ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end,
+    ASIO_MOVE_ARG(IteratorConnectHandler) handler);
+
+/// Asynchronously establishes a socket connection by trying each endpoint in a
+/// sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c async_connect
+ * member function, once for each endpoint in the sequence, until a connection
+ * is successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param endpoints A sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @param handler The handler to be called when the connect operation
+ * completes. Copies will be made of the handler as required. The function
+ * signature of the handler must be:
+ * @code void handler(
+ *   // Result of operation. if the sequence is empty, set to
+ *   // asio::error::not_found. Otherwise, contains the
+ *   // error from the last connection attempt.
+ *   const asio::error_code& error,
+ *
+ *   // On success, an iterator denoting the successfully
+ *   // connected endpoint. Otherwise, the end iterator.
+ *   Iterator iterator
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation
+ * of the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * The following connect condition function object can be used to output
+ * information about the individual connection attempts:
+ * @code struct my_connect_condition
+ * {
+ *   bool operator()(
+ *       const asio::error_code& ec,
+ *       const::tcp::endpoint& next)
+ *   {
+ *     if (ec) std::cout << "Error: " << ec.message() << std::endl;
+ *     std::cout << "Trying: " << next << std::endl;
+ *     return true;
+ *   }
+ * }; @endcode
+ * It would be used with the asio::connect function as follows:
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::socket s(io_context);
+ *
+ * // ...
+ *
+ * r.async_resolve(q, resolve_handler);
+ *
+ * // ...
+ *
+ * void resolve_handler(
+ *     const asio::error_code& ec,
+ *     tcp::resolver::results_type results)
+ * {
+ *   if (!ec)
+ *   {
+ *     asio::async_connect(s, results,
+ *         my_connect_condition(),
+ *         connect_handler);
+ *   }
+ * }
+ *
+ * // ...
+ *
+ * void connect_handler(
+ *     const asio::error_code& ec,
+ *     const tcp::endpoint& endpoint)
+ * {
+ *   if (ec)
+ *   {
+ *     // An error occurred.
+ *   }
+ *   else
+ *   {
+ *     std::cout << "Connected to: " << endpoint << std::endl;
+ *   }
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename EndpointSequence,
+    typename ConnectCondition, typename RangeConnectHandler>
+ASIO_INITFN_RESULT_TYPE(RangeConnectHandler,
+    void (asio::error_code, typename Protocol::endpoint))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, ConnectCondition connect_condition,
+    ASIO_MOVE_ARG(RangeConnectHandler) handler,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type* = 0);
+
+#if !defined(ASIO_NO_DEPRECATED)
+/// (Deprecated: Use range overload.) Asynchronously establishes a socket
+/// connection by trying each endpoint in a sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c async_connect
+ * member function, once for each endpoint in the sequence, until a connection
+ * is successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @param handler The handler to be called when the connect operation
+ * completes. Copies will be made of the handler as required. The function
+ * signature of the handler must be:
+ * @code void handler(
+ *   // Result of operation. if the sequence is empty, set to
+ *   // asio::error::not_found. Otherwise, contains the
+ *   // error from the last connection attempt.
+ *   const asio::error_code& error,
+ *
+ *   // On success, an iterator denoting the successfully
+ *   // connected endpoint. Otherwise, the end iterator.
+ *   Iterator iterator
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation
+ * of the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note This overload assumes that a default constructed object of type @c
+ * Iterator represents the end of the sequence. This is a valid assumption for
+ * iterator types such as @c asio::ip::tcp::resolver::iterator.
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+    typename ConnectCondition, typename IteratorConnectHandler>
+ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s, Iterator begin,
+    ConnectCondition connect_condition,
+    ASIO_MOVE_ARG(IteratorConnectHandler) handler,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type* = 0);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Asynchronously establishes a socket connection by trying each endpoint in a
+/// sequence.
+/**
+ * This function attempts to connect a socket to one of a sequence of
+ * endpoints. It does this by repeated calls to the socket's @c async_connect
+ * member function, once for each endpoint in the sequence, until a connection
+ * is successfully established.
+ *
+ * @param s The socket to be connected. If the socket is already open, it will
+ * be closed.
+ *
+ * @param begin An iterator pointing to the start of a sequence of endpoints.
+ *
+ * @param end An iterator pointing to the end of a sequence of endpoints.
+ *
+ * @param connect_condition A function object that is called prior to each
+ * connection attempt. The signature of the function object must be:
+ * @code bool connect_condition(
+ *     const asio::error_code& ec,
+ *     const typename Protocol::endpoint& next); @endcode
+ * The @c ec parameter contains the result from the most recent connect
+ * operation. Before the first connection attempt, @c ec is always set to
+ * indicate success. The @c next parameter is the next endpoint to be tried.
+ * The function object should return true if the next endpoint should be tried,
+ * and false if it should be skipped.
+ *
+ * @param handler The handler to be called when the connect operation
+ * completes. Copies will be made of the handler as required. The function
+ * signature of the handler must be:
+ * @code void handler(
+ *   // Result of operation. if the sequence is empty, set to
+ *   // asio::error::not_found. Otherwise, contains the
+ *   // error from the last connection attempt.
+ *   const asio::error_code& error,
+ *
+ *   // On success, an iterator denoting the successfully
+ *   // connected endpoint. Otherwise, the end iterator.
+ *   Iterator iterator
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation
+ * of the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * The following connect condition function object can be used to output
+ * information about the individual connection attempts:
+ * @code struct my_connect_condition
+ * {
+ *   bool operator()(
+ *       const asio::error_code& ec,
+ *       const::tcp::endpoint& next)
+ *   {
+ *     if (ec) std::cout << "Error: " << ec.message() << std::endl;
+ *     std::cout << "Trying: " << next << std::endl;
+ *     return true;
+ *   }
+ * }; @endcode
+ * It would be used with the asio::connect function as follows:
+ * @code tcp::resolver r(io_context);
+ * tcp::resolver::query q("host", "service");
+ * tcp::socket s(io_context);
+ *
+ * // ...
+ *
+ * r.async_resolve(q, resolve_handler);
+ *
+ * // ...
+ *
+ * void resolve_handler(
+ *     const asio::error_code& ec,
+ *     tcp::resolver::iterator i)
+ * {
+ *   if (!ec)
+ *   {
+ *     tcp::resolver::iterator end;
+ *     asio::async_connect(s, i, end,
+ *         my_connect_condition(),
+ *         connect_handler);
+ *   }
+ * }
+ *
+ * // ...
+ *
+ * void connect_handler(
+ *     const asio::error_code& ec,
+ *     tcp::resolver::iterator i)
+ * {
+ *   if (ec)
+ *   {
+ *     // An error occurred.
+ *   }
+ *   else
+ *   {
+ *     std::cout << "Connected to: " << i->endpoint() << std::endl;
+ *   }
+ * } @endcode
+ */
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+    typename ConnectCondition, typename IteratorConnectHandler>
+ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end, ConnectCondition connect_condition,
+    ASIO_MOVE_ARG(IteratorConnectHandler) handler);
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/connect.hpp"
+
+#endif
diff --git a/subprojects/asio/include/asio/coroutine.hpp b/subprojects/asio/include/asio/coroutine.hpp
new file mode 100644
index 000000000..cd2d99e53
--- /dev/null
+++ b/subprojects/asio/include/asio/coroutine.hpp
@@ -0,0 +1,328 @@
+//
+// coroutine.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_COROUTINE_HPP
+#define ASIO_COROUTINE_HPP
+
+namespace asio {
+namespace detail {
+
+class coroutine_ref;
+
+} // namespace detail
+
+/// Provides support for implementing stackless coroutines.
+/**
+ * The @c coroutine class may be used to implement stackless coroutines. The
+ * class itself is used to store the current state of the coroutine.
+ *
+ * Coroutines are copy-constructible and assignable, and the space overhead is
+ * a single int. They can be used as a base class:
+ *
+ * @code class session : coroutine
+ * {
+ *   ...
+ * }; @endcode
+ *
+ * or as a data member:
+ *
+ * @code class session
+ * {
+ *   ...
+ *   coroutine coro_;
+ * }; @endcode
+ *
+ * or even bound in as a function argument using lambdas or @c bind(). The
+ * important thing is that as the application maintains a copy of the object
+ * for as long as the coroutine must be kept alive.
+ *
+ * @par Pseudo-keywords
+ *
+ * A coroutine is used in conjunction with certain "pseudo-keywords", which
+ * are implemented as macros. These macros are defined by a header file:
+ *
+ * @code #include <asio/yield.hpp>@endcode
+ *
+ * and may conversely be undefined as follows:
+ *
+ * @code #include <asio/unyield.hpp>@endcode
+ *
+ * <b>reenter</b>
+ *
+ * The @c reenter macro is used to define the body of a coroutine. It takes a
+ * single argument: a pointer or reference to a coroutine object. For example,
+ * if the base class is a coroutine object you may write:
+ *
+ * @code reenter (this)
+ * {
+ *   ... coroutine body ...
+ * } @endcode
+ *
+ * and if a data member or other variable you can write:
+ *
+ * @code reenter (coro_)
+ * {
+ *   ... coroutine body ...
+ * } @endcode
+ *
+ * When @c reenter is executed at runtime, control jumps to the location of the
+ * last @c yield or @c fork.
+ *
+ * The coroutine body may also be a single statement, such as:
+ *
+ * @code reenter (this) for (;;)
+ * {
+ *   ...
+ * } @endcode
+ *
+ * @b Limitation: The @c reenter macro is implemented using a switch. This
+ * means that you must take care when using local variables within the
+ * coroutine body. The local variable is not allowed in a position where
+ * reentering the coroutine could bypass the variable definition.
+ *
+ * <b>yield <em>statement</em></b>
+ *
+ * This form of the @c yield keyword is often used with asynchronous operations:
+ *
+ * @code yield socket_->async_read_some(buffer(*buffer_), *this); @endcode
+ *
+ * This divides into four logical steps:
+ *
+ * @li @c yield saves the current state of the coroutine.
+ * @li The statement initiates the asynchronous operation.
+ * @li The resume point is defined immediately following the statement.
+ * @li Control is transferred to the end of the coroutine body.
+ *
+ * When the asynchronous operation completes, the function object is invoked
+ * and @c reenter causes control to transfer to the resume point. It is
+ * important to remember to carry the coroutine state forward with the
+ * asynchronous operation. In the above snippet, the current class is a
+ * function object object with a coroutine object as base class or data member.
+ *
+ * The statement may also be a compound statement, and this permits us to
+ * define local variables with limited scope:
+ *
+ * @code yield
+ * {
+ *   mutable_buffers_1 b = buffer(*buffer_);
+ *   socket_->async_read_some(b, *this);
+ * } @endcode
+ *
+ * <b>yield return <em>expression</em> ;</b>
+ *
+ * This form of @c yield is often used in generators or coroutine-based parsers.
+ * For example, the function object:
+ *
+ * @code struct interleave : coroutine
+ * {
+ *   istream& is1;
+ *   istream& is2;
+ *   char operator()(char c)
+ *   {
+ *     reenter (this) for (;;)
+ *     {
+ *       yield return is1.get();
+ *       yield return is2.get();
+ *     }
+ *   }
+ * }; @endcode
+ *
+ * defines a trivial coroutine that interleaves the characters from two input
+ * streams.
+ *
+ * This type of @c yield divides into three logical steps:
+ *
+ * @li @c yield saves the current state of the coroutine.
+ * @li The resume point is defined immediately following the semicolon.
+ * @li The value of the expression is returned from the function.
+ *
+ * <b>yield ;</b>
+ *
+ * This form of @c yield is equivalent to the following steps:
+ *
+ * @li @c yield saves the current state of the coroutine.
+ * @li The resume point is defined immediately following the semicolon.
+ * @li Control is transferred to the end of the coroutine body.
+ *
+ * This form might be applied when coroutines are used for cooperative
+ * threading and scheduling is explicitly managed. For example:
+ *
+ * @code struct task : coroutine
+ * {
+ *   ...
+ *   void operator()()
+ *   {
+ *     reenter (this)
+ *     {
+ *       while (... not finished ...)
+ *       {
+ *         ... do something ...
+ *         yield;
+ *         ... do some more ...
+ *         yield;
+ *       }
+ *     }
+ *   }
+ *   ...
+ * };
+ * ...
+ * task t1, t2;
+ * for (;;)
+ * {
+ *   t1();
+ *   t2();
+ * } @endcode
+ *
+ * <b>yield break ;</b>
+ *
+ * The final form of @c yield is used to explicitly terminate the coroutine.
+ * This form is comprised of two steps:
+ *
+ * @li @c yield sets the coroutine state to indicate termination.
+ * @li Control is transferred to the end of the coroutine body.
+ *
+ * Once terminated, calls to is_complete() return true and the coroutine cannot
+ * be reentered.
+ *
+ * Note that a coroutine may also be implicitly terminated if the coroutine
+ * body is exited without a yield, e.g. by return, throw or by running to the
+ * end of the body.
+ *
+ * <b>fork <em>statement</em></b>
+ *
+ * The @c fork pseudo-keyword is used when "forking" a coroutine, i.e. splitting
+ * it into two (or more) copies. One use of @c fork is in a server, where a new
+ * coroutine is created to handle each client connection:
+ * 
+ * @code reenter (this)
+ * {
+ *   do
+ *   {
+ *     socket_.reset(new tcp::socket(io_context_));
+ *     yield acceptor->async_accept(*socket_, *this);
+ *     fork server(*this)();
+ *   } while (is_parent());
+ *   ... client-specific handling follows ...
+ * } @endcode
+ * 
+ * The logical steps involved in a @c fork are:
+ * 
+ * @li @c fork saves the current state of the coroutine.
+ * @li The statement creates a copy of the coroutine and either executes it
+ *     immediately or schedules it for later execution.
+ * @li The resume point is defined immediately following the semicolon.
+ * @li For the "parent", control immediately continues from the next line.
+ *
+ * The functions is_parent() and is_child() can be used to differentiate
+ * between parent and child. You would use these functions to alter subsequent
+ * control flow.
+ *
+ * Note that @c fork doesn't do the actual forking by itself. It is the
+ * application's responsibility to create a clone of the coroutine and call it.
+ * The clone can be called immediately, as above, or scheduled for delayed
+ * execution using something like io_context::post().
+ *
+ * @par Alternate macro names
+ *
+ * If preferred, an application can use macro names that follow a more typical
+ * naming convention, rather than the pseudo-keywords. These are:
+ *
+ * @li @c ASIO_CORO_REENTER instead of @c reenter
+ * @li @c ASIO_CORO_YIELD instead of @c yield
+ * @li @c ASIO_CORO_FORK instead of @c fork
+ */
+class coroutine
+{
+public:
+  /// Constructs a coroutine in its initial state.
+  coroutine() : value_(0) {}
+
+  /// Returns true if the coroutine is the child of a fork.
+  bool is_child() const { return value_ < 0; }
+
+  /// Returns true if the coroutine is the parent of a fork.
+  bool is_parent() const { return !is_child(); }
+
+  /// Returns true if the coroutine has reached its terminal state.
+  bool is_complete() const { return value_ == -1; }
+
+private:
+  friend class detail::coroutine_ref;
+  int value_;
+};
+
+
+namespace detail {
+
+class coroutine_ref
+{
+public:
+  coroutine_ref(coroutine& c) : value_(c.value_), modified_(false) {}
+  coroutine_ref(coroutine* c) : value_(c->value_), modified_(false) {}
+  ~coroutine_ref() { if (!modified_) value_ = -1; }
+  operator int() const { return value_; }
+  int& operator=(int v) { modified_ = true; return value_ = v; }
+private:
+  void operator=(const coroutine_ref&);
+  int& value_;
+  bool modified_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#define ASIO_CORO_REENTER(c) \
+  switch (::asio::detail::coroutine_ref _coro_value = c) \
+    case -1: if (_coro_value) \
+    { \
+      goto terminate_coroutine; \
+      terminate_coroutine: \
+      _coro_value = -1; \
+      goto bail_out_of_coroutine; \
+      bail_out_of_coroutine: \
+      break; \
+    } \
+    else /* fall-through */ case 0:
+
+#define ASIO_CORO_YIELD_IMPL(n) \
+  for (_coro_value = (n);;) \
+    if (_coro_value == 0) \
+    { \
+      case (n): ; \
+      break; \
+    } \
+    else \
+      switch (_coro_value ? 0 : 1) \
+        for (;;) \
+          /* fall-through */ case -1: if (_coro_value) \
+            goto terminate_coroutine; \
+          else for (;;) \
+            /* fall-through */ case 1: if (_coro_value) \
+              goto bail_out_of_coroutine; \
+            else /* fall-through */ case 0:
+
+#define ASIO_CORO_FORK_IMPL(n) \
+  for (_coro_value = -(n);; _coro_value = (n)) \
+    if (_coro_value == (n)) \
+    { \
+      case -(n): ; \
+      break; \
+    } \
+    else
+
+#if defined(_MSC_VER)
+# define ASIO_CORO_YIELD ASIO_CORO_YIELD_IMPL(__COUNTER__ + 1)
+# define ASIO_CORO_FORK ASIO_CORO_FORK_IMPL(__COUNTER__ + 1)
+#else // defined(_MSC_VER)
+# define ASIO_CORO_YIELD ASIO_CORO_YIELD_IMPL(__LINE__)
+# define ASIO_CORO_FORK ASIO_CORO_FORK_IMPL(__LINE__)
+#endif // defined(_MSC_VER)
+
+#endif // ASIO_COROUTINE_HPP
diff --git a/subprojects/asio/include/asio/datagram_socket_service.hpp b/subprojects/asio/include/asio/datagram_socket_service.hpp
new file mode 100644
index 000000000..7dc1a3b34
--- /dev/null
+++ b/subprojects/asio/include/asio/datagram_socket_service.hpp
@@ -0,0 +1,466 @@
+//
+// datagram_socket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DATAGRAM_SOCKET_SERVICE_HPP
+#define ASIO_DATAGRAM_SOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/null_socket_service.hpp"
+#elif defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_socket_service.hpp"
+#else
+# include "asio/detail/reactive_socket_service.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a datagram socket.
+template <typename Protocol>
+class datagram_socket_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<datagram_socket_service<Protocol> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+private:
+  // The type of the platform-specific implementation.
+#if defined(ASIO_WINDOWS_RUNTIME)
+  typedef detail::null_socket_service<Protocol> service_impl_type;
+#elif defined(ASIO_HAS_IOCP)
+  typedef detail::win_iocp_socket_service<Protocol> service_impl_type;
+#else
+  typedef detail::reactive_socket_service<Protocol> service_impl_type;
+#endif
+
+public:
+  /// The type of a datagram socket.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native socket type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new datagram socket service for the specified io_context.
+  explicit datagram_socket_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        datagram_socket_service<Protocol> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new datagram socket implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new datagram socket implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another datagram socket implementation.
+  void move_assign(implementation_type& impl,
+      datagram_socket_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+
+  // All socket services have access to each other's implementations.
+  template <typename Protocol1> friend class datagram_socket_service;
+
+  /// Move-construct a new datagram socket implementation from another protocol
+  /// type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      datagram_socket_service<Protocol1>& other_service,
+      typename datagram_socket_service<
+        Protocol1>::implementation_type& other_impl,
+      typename enable_if<is_convertible<
+        Protocol1, Protocol>::value>::type* = 0)
+  {
+    service_impl_.template converting_move_construct<Protocol1>(
+        impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a datagram socket implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  // Open a new datagram socket implementation.
+  ASIO_SYNC_OP_VOID open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    if (protocol.type() == ASIO_OS_DEF(SOCK_DGRAM))
+      service_impl_.open(impl, protocol, ec);
+    else
+      ec = asio::error::invalid_argument;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native socket to a datagram socket.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_socket,
+      asio::error_code& ec)
+  {
+    service_impl_.assign(impl, protocol, native_socket, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a datagram socket implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Release ownership of the underlying socket.
+  native_handle_type release(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return service_impl_.release(impl, ec);
+  }
+
+  /// Get the native socket implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the socket.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.at_mark(impl, ec);
+  }
+
+  /// Determine the number of bytes available for reading.
+  std::size_t available(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.available(impl, ec);
+  }
+
+  // Bind the datagram socket to the specified local endpoint.
+  ASIO_SYNC_OP_VOID bind(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    service_impl_.bind(impl, endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Connect the datagram socket to the specified endpoint.
+  ASIO_SYNC_OP_VOID connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    service_impl_.connect(impl, peer_endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous connect.
+  template <typename ConnectHandler>
+  ASIO_INITFN_RESULT_TYPE(ConnectHandler,
+      void (asio::error_code))
+  async_connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint,
+      ASIO_MOVE_ARG(ConnectHandler) handler)
+  {
+    async_completion<ConnectHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_connect(impl, peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Set a socket option.
+  template <typename SettableSocketOption>
+  ASIO_SYNC_OP_VOID set_option(implementation_type& impl,
+      const SettableSocketOption& option, asio::error_code& ec)
+  {
+    service_impl_.set_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get a socket option.
+  template <typename GettableSocketOption>
+  ASIO_SYNC_OP_VOID get_option(const implementation_type& impl,
+      GettableSocketOption& option, asio::error_code& ec) const
+  {
+    service_impl_.get_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the socket.
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(implementation_type& impl,
+      IoControlCommand& command, asio::error_code& ec)
+  {
+    service_impl_.io_control(impl, command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the socket.
+  bool non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the socket.
+  ASIO_SYNC_OP_VOID non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.native_non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the native socket implementation.
+  ASIO_SYNC_OP_VOID native_non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.native_non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.local_endpoint(impl, ec);
+  }
+
+  /// Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.remote_endpoint(impl, ec);
+  }
+
+  /// Disable sends or receives on the socket.
+  ASIO_SYNC_OP_VOID shutdown(implementation_type& impl,
+      socket_base::shutdown_type what, asio::error_code& ec)
+  {
+    service_impl_.shutdown(impl, what, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the socket to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  ASIO_SYNC_OP_VOID wait(implementation_type& impl,
+      socket_base::wait_type w, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the socket to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl, socket_base::wait_type w,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, w, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Send the given data to the peer.
+  template <typename ConstBufferSequence>
+  std::size_t send(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.send(impl, buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(implementation_type& impl, const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_send(impl, buffers, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Send a datagram to the specified endpoint.
+  template <typename ConstBufferSequence>
+  std::size_t send_to(implementation_type& impl,
+      const ConstBufferSequence& buffers, const endpoint_type& destination,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.send_to(impl, buffers, destination, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send_to(implementation_type& impl,
+      const ConstBufferSequence& buffers, const endpoint_type& destination,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_send_to(impl, buffers,
+        destination, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Receive some data from the peer.
+  template <typename MutableBufferSequence>
+  std::size_t receive(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.receive(impl, buffers, flags, ec);
+  }
+
+  /// Start an asynchronous receive.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_receive(impl, buffers, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Receive a datagram with the endpoint of the sender.
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers, endpoint_type& sender_endpoint,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.receive_from(impl, buffers, sender_endpoint, flags,
+        ec);
+  }
+
+  /// Start an asynchronous receive that will get the endpoint of the sender.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers, endpoint_type& sender_endpoint,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_receive_from(impl, buffers,
+        sender_endpoint, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_DATAGRAM_SOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/deadline_timer.hpp b/subprojects/asio/include/asio/deadline_timer.hpp
new file mode 100644
index 000000000..5a2155474
--- /dev/null
+++ b/subprojects/asio/include/asio/deadline_timer.hpp
@@ -0,0 +1,38 @@
+//
+// deadline_timer.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DEADLINE_TIMER_HPP
+#define ASIO_DEADLINE_TIMER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/detail/socket_types.hpp" // Must come before posix_time.
+#include "asio/basic_deadline_timer.hpp"
+
+#include <boost/date_time/posix_time/posix_time_types.hpp>
+
+namespace asio {
+
+/// Typedef for the typical usage of timer. Uses a UTC clock.
+typedef basic_deadline_timer<boost::posix_time::ptime> deadline_timer;
+
+} // namespace asio
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_DEADLINE_TIMER_HPP
diff --git a/subprojects/asio/include/asio/deadline_timer_service.hpp b/subprojects/asio/include/asio/deadline_timer_service.hpp
new file mode 100644
index 000000000..2dcc83e2f
--- /dev/null
+++ b/subprojects/asio/include/asio/deadline_timer_service.hpp
@@ -0,0 +1,173 @@
+//
+// deadline_timer_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DEADLINE_TIMER_SERVICE_HPP
+#define ASIO_DEADLINE_TIMER_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/deadline_timer_service.hpp"
+#include "asio/io_context.hpp"
+#include "asio/time_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a timer.
+template <typename TimeType,
+    typename TimeTraits = asio::time_traits<TimeType> >
+class deadline_timer_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<
+      deadline_timer_service<TimeType, TimeTraits> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The time traits type.
+  typedef TimeTraits traits_type;
+
+  /// The time type.
+  typedef typename traits_type::time_type time_type;
+
+  /// The duration type.
+  typedef typename traits_type::duration_type duration_type;
+
+private:
+  // The type of the platform-specific implementation.
+  typedef detail::deadline_timer_service<traits_type> service_impl_type;
+
+public:
+  /// The implementation type of the deadline timer.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// Construct a new timer service for the specified io_context.
+  explicit deadline_timer_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        deadline_timer_service<TimeType, TimeTraits> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new timer implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+  /// Destroy a timer implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Cancel any asynchronous wait operations associated with the timer.
+  std::size_t cancel(implementation_type& impl, asio::error_code& ec)
+  {
+    return service_impl_.cancel(impl, ec);
+  }
+
+  /// Cancels one asynchronous wait operation associated with the timer.
+  std::size_t cancel_one(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return service_impl_.cancel_one(impl, ec);
+  }
+
+  /// Get the expiry time for the timer as an absolute time.
+  time_type expires_at(const implementation_type& impl) const
+  {
+    return service_impl_.expiry(impl);
+  }
+
+  /// Set the expiry time for the timer as an absolute time.
+  std::size_t expires_at(implementation_type& impl,
+      const time_type& expiry_time, asio::error_code& ec)
+  {
+    return service_impl_.expires_at(impl, expiry_time, ec);
+  }
+
+  /// Get the expiry time for the timer relative to now.
+  duration_type expires_from_now(const implementation_type& impl) const
+  {
+    return TimeTraits::subtract(service_impl_.expiry(impl), TimeTraits::now());
+  }
+
+  /// Set the expiry time for the timer relative to now.
+  std::size_t expires_from_now(implementation_type& impl,
+      const duration_type& expiry_time, asio::error_code& ec)
+  {
+    return service_impl_.expires_after(impl, expiry_time, ec);
+  }
+
+  // Perform a blocking wait on the timer.
+  void wait(implementation_type& impl, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, ec);
+  }
+
+  // Start an asynchronous wait on the timer.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_DEADLINE_TIMER_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/defer.hpp b/subprojects/asio/include/asio/defer.hpp
new file mode 100644
index 000000000..a0897f2f8
--- /dev/null
+++ b/subprojects/asio/include/asio/defer.hpp
@@ -0,0 +1,107 @@
+//
+// defer.hpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DEFER_HPP
+#define ASIO_DEFER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/is_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Submits a completion token or function object for execution.
+/**
+ * This function submits an object for execution using the object's associated
+ * executor. The function object is queued for execution, and is never called
+ * from the current thread prior to returning from <tt>defer()</tt>.
+ *
+ * This function has the following effects:
+ *
+ * @li Constructs a function object handler of type @c Handler, initialized
+ * with <tt>handler(forward<CompletionToken>(token))</tt>.
+ *
+ * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
+ * initializing the object as <tt>result(handler)</tt>.
+ *
+ * @li Obtains the handler's associated executor object @c ex by performing
+ * <tt>get_associated_executor(handler)</tt>.
+ *
+ * @li Obtains the handler's associated allocator object @c alloc by performing
+ * <tt>get_associated_allocator(handler)</tt>.
+ *
+ * @li Performs <tt>ex.defer(std::move(handler), alloc)</tt>.
+ *
+ * @li Returns <tt>result.get()</tt>.
+ */
+template <typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) defer(
+    ASIO_MOVE_ARG(CompletionToken) token);
+
+/// Submits a completion token or function object for execution.
+/**
+ * This function submits an object for execution using the specified executor.
+ * The function object is queued for execution, and is never called from the
+ * current thread prior to returning from <tt>defer()</tt>.
+ *
+ * This function has the following effects:
+ *
+ * @li Constructs a function object handler of type @c Handler, initialized
+ * with <tt>handler(forward<CompletionToken>(token))</tt>.
+ *
+ * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
+ * initializing the object as <tt>result(handler)</tt>.
+ *
+ * @li Obtains the handler's associated executor object @c ex1 by performing
+ * <tt>get_associated_executor(handler)</tt>.
+ *
+ * @li Creates a work object @c w by performing <tt>make_work(ex1)</tt>.
+ *
+ * @li Obtains the handler's associated allocator object @c alloc by performing
+ * <tt>get_associated_allocator(handler)</tt>.
+ *
+ * @li Constructs a function object @c f with a function call operator that
+ * performs <tt>ex1.dispatch(std::move(handler), alloc)</tt> followed by
+ * <tt>w.reset()</tt>.
+ *
+ * @li Performs <tt>Executor(ex).defer(std::move(f), alloc)</tt>.
+ *
+ * @li Returns <tt>result.get()</tt>.
+ */
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) defer(
+    const Executor& ex, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_executor<Executor>::value>::type* = 0);
+
+/// Submits a completion token or function object for execution.
+/**
+ * @returns <tt>defer(ctx.get_executor(), forward<CompletionToken>(token))</tt>.
+ */
+template <typename ExecutionContext, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) defer(
+    ExecutionContext& ctx, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type* = 0);
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/defer.hpp"
+
+#endif // ASIO_DEFER_HPP
diff --git a/subprojects/asio/include/asio/detail/array.hpp b/subprojects/asio/include/asio/detail/array.hpp
new file mode 100644
index 000000000..ba4297462
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/array.hpp
@@ -0,0 +1,38 @@
+//
+// detail/array.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_ARRAY_HPP
+#define ASIO_DETAIL_ARRAY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_ARRAY)
+# include <array>
+#else // defined(ASIO_HAS_STD_ARRAY)
+# include <boost/array.hpp>
+#endif // defined(ASIO_HAS_STD_ARRAY)
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_STD_ARRAY)
+using std::array;
+#else // defined(ASIO_HAS_STD_ARRAY)
+using boost::array;
+#endif // defined(ASIO_HAS_STD_ARRAY)
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_ARRAY_HPP
diff --git a/subprojects/asio/include/asio/detail/array_fwd.hpp b/subprojects/asio/include/asio/detail/array_fwd.hpp
new file mode 100644
index 000000000..4161db0db
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/array_fwd.hpp
@@ -0,0 +1,34 @@
+//
+// detail/array_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_ARRAY_FWD_HPP
+#define ASIO_DETAIL_ARRAY_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+namespace boost {
+
+template<class T, std::size_t N>
+class array;
+
+} // namespace boost
+
+// Standard library components can't be forward declared, so we'll have to
+// include the array header. Fortunately, it's fairly lightweight and doesn't
+// add significantly to the compile time.
+#if defined(ASIO_HAS_STD_ARRAY)
+# include <array>
+#endif // defined(ASIO_HAS_STD_ARRAY)
+
+#endif // ASIO_DETAIL_ARRAY_FWD_HPP
diff --git a/subprojects/asio/include/asio/detail/assert.hpp b/subprojects/asio/include/asio/detail/assert.hpp
new file mode 100644
index 000000000..a952a441f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/assert.hpp
@@ -0,0 +1,32 @@
+//
+// detail/assert.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_ASSERT_HPP
+#define ASIO_DETAIL_ASSERT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_ASSERT)
+# include <boost/assert.hpp>
+#else // defined(ASIO_HAS_BOOST_ASSERT)
+# include <cassert>
+#endif // defined(ASIO_HAS_BOOST_ASSERT)
+
+#if defined(ASIO_HAS_BOOST_ASSERT)
+# define ASIO_ASSERT(expr) BOOST_ASSERT(expr)
+#else // defined(ASIO_HAS_BOOST_ASSERT)
+# define ASIO_ASSERT(expr) assert(expr)
+#endif // defined(ASIO_HAS_BOOST_ASSERT)
+
+#endif // ASIO_DETAIL_ASSERT_HPP
diff --git a/subprojects/asio/include/asio/detail/atomic_count.hpp b/subprojects/asio/include/asio/detail/atomic_count.hpp
new file mode 100644
index 000000000..2bf75a535
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/atomic_count.hpp
@@ -0,0 +1,45 @@
+//
+// detail/atomic_count.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_ATOMIC_COUNT_HPP
+#define ASIO_DETAIL_ATOMIC_COUNT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+// Nothing to include.
+#elif defined(ASIO_HAS_STD_ATOMIC)
+# include <atomic>
+#else // defined(ASIO_HAS_STD_ATOMIC)
+# include <boost/detail/atomic_count.hpp>
+#endif // defined(ASIO_HAS_STD_ATOMIC)
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS)
+typedef long atomic_count;
+inline void increment(atomic_count& a, long b) { a += b; }
+#elif defined(ASIO_HAS_STD_ATOMIC)
+typedef std::atomic<long> atomic_count;
+inline void increment(atomic_count& a, long b) { a += b; }
+#else // defined(ASIO_HAS_STD_ATOMIC)
+typedef boost::detail::atomic_count atomic_count;
+inline void increment(atomic_count& a, long b) { while (b > 0) ++a, --b; }
+#endif // defined(ASIO_HAS_STD_ATOMIC)
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_ATOMIC_COUNT_HPP
diff --git a/subprojects/asio/include/asio/detail/base_from_completion_cond.hpp b/subprojects/asio/include/asio/detail/base_from_completion_cond.hpp
new file mode 100644
index 000000000..73b4a957f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/base_from_completion_cond.hpp
@@ -0,0 +1,68 @@
+//
+// detail/base_from_completion_cond.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_BASE_FROM_COMPLETION_COND_HPP
+#define ASIO_DETAIL_BASE_FROM_COMPLETION_COND_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/completion_condition.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename CompletionCondition>
+class base_from_completion_cond
+{
+protected:
+  explicit base_from_completion_cond(CompletionCondition completion_condition)
+    : completion_condition_(completion_condition)
+  {
+  }
+
+  std::size_t check_for_completion(
+      const asio::error_code& ec,
+      std::size_t total_transferred)
+  {
+    return detail::adapt_completion_condition_result(
+        completion_condition_(ec, total_transferred));
+  }
+
+private:
+  CompletionCondition completion_condition_;
+};
+
+template <>
+class base_from_completion_cond<transfer_all_t>
+{
+protected:
+  explicit base_from_completion_cond(transfer_all_t)
+  {
+  }
+
+  static std::size_t check_for_completion(
+      const asio::error_code& ec,
+      std::size_t total_transferred)
+  {
+    return transfer_all_t()(ec, total_transferred);
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_BASE_FROM_COMPLETION_COND_HPP
diff --git a/subprojects/asio/include/asio/detail/bind_handler.hpp b/subprojects/asio/include/asio/detail/bind_handler.hpp
new file mode 100644
index 000000000..0f4f066d8
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/bind_handler.hpp
@@ -0,0 +1,816 @@
+//
+// detail/bind_handler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_BIND_HANDLER_HPP
+#define ASIO_DETAIL_BIND_HANDLER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler, typename Arg1>
+class binder1
+{
+public:
+  template <typename T>
+  binder1(int, ASIO_MOVE_ARG(T) handler, const Arg1& arg1)
+    : handler_(ASIO_MOVE_CAST(T)(handler)),
+      arg1_(arg1)
+  {
+  }
+
+  binder1(Handler& handler, const Arg1& arg1)
+    : handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      arg1_(arg1)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  binder1(const binder1& other)
+    : handler_(other.handler_),
+      arg1_(other.arg1_)
+  {
+  }
+
+  binder1(binder1&& other)
+    : handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(other.arg1_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    handler_(static_cast<const Arg1&>(arg1_));
+  }
+
+  void operator()() const
+  {
+    handler_(arg1_);
+  }
+
+//private:
+  Handler handler_;
+  Arg1 arg1_;
+};
+
+template <typename Handler, typename Arg1>
+inline void* asio_handler_allocate(std::size_t size,
+    binder1<Handler, Arg1>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    binder1<Handler, Arg1>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1>
+inline bool asio_handler_is_continuation(
+    binder1<Handler, Arg1>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1>
+inline void asio_handler_invoke(Function& function,
+    binder1<Handler, Arg1>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1>
+inline void asio_handler_invoke(const Function& function,
+    binder1<Handler, Arg1>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1>
+inline binder1<typename decay<Handler>::type, Arg1> bind_handler(
+    ASIO_MOVE_ARG(Handler) handler, const Arg1& arg1)
+{
+  return binder1<typename decay<Handler>::type, Arg1>(0,
+      ASIO_MOVE_CAST(Handler)(handler), arg1);
+}
+
+template <typename Handler, typename Arg1, typename Arg2>
+class binder2
+{
+public:
+  template <typename T>
+  binder2(int, ASIO_MOVE_ARG(T) handler,
+      const Arg1& arg1, const Arg2& arg2)
+    : handler_(ASIO_MOVE_CAST(T)(handler)),
+      arg1_(arg1),
+      arg2_(arg2)
+  {
+  }
+
+  binder2(Handler& handler, const Arg1& arg1, const Arg2& arg2)
+    : handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      arg1_(arg1),
+      arg2_(arg2)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  binder2(const binder2& other)
+    : handler_(other.handler_),
+      arg1_(other.arg1_),
+      arg2_(other.arg2_)
+  {
+  }
+
+  binder2(binder2&& other)
+    : handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(other.arg1_)),
+      arg2_(ASIO_MOVE_CAST(Arg2)(other.arg2_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_));
+  }
+
+  void operator()() const
+  {
+    handler_(arg1_, arg2_);
+  }
+
+//private:
+  Handler handler_;
+  Arg1 arg1_;
+  Arg2 arg2_;
+};
+
+template <typename Handler, typename Arg1, typename Arg2>
+inline void* asio_handler_allocate(std::size_t size,
+    binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2>
+inline bool asio_handler_is_continuation(
+    binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1, typename Arg2>
+inline void asio_handler_invoke(Function& function,
+    binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1, typename Arg2>
+inline void asio_handler_invoke(const Function& function,
+    binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2>
+inline binder2<typename decay<Handler>::type, Arg1, Arg2> bind_handler(
+    ASIO_MOVE_ARG(Handler) handler, const Arg1& arg1, const Arg2& arg2)
+{
+  return binder2<typename decay<Handler>::type, Arg1, Arg2>(0,
+      ASIO_MOVE_CAST(Handler)(handler), arg1, arg2);
+}
+
+template <typename Handler, typename Arg1, typename Arg2, typename Arg3>
+class binder3
+{
+public:
+  template <typename T>
+  binder3(int, ASIO_MOVE_ARG(T) handler, const Arg1& arg1,
+      const Arg2& arg2, const Arg3& arg3)
+    : handler_(ASIO_MOVE_CAST(T)(handler)),
+      arg1_(arg1),
+      arg2_(arg2),
+      arg3_(arg3)
+  {
+  }
+
+  binder3(Handler& handler, const Arg1& arg1,
+      const Arg2& arg2, const Arg3& arg3)
+    : handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      arg1_(arg1),
+      arg2_(arg2),
+      arg3_(arg3)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  binder3(const binder3& other)
+    : handler_(other.handler_),
+      arg1_(other.arg1_),
+      arg2_(other.arg2_),
+      arg3_(other.arg3_)
+  {
+  }
+
+  binder3(binder3&& other)
+    : handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(other.arg1_)),
+      arg2_(ASIO_MOVE_CAST(Arg2)(other.arg2_)),
+      arg3_(ASIO_MOVE_CAST(Arg3)(other.arg3_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_), static_cast<const Arg3&>(arg3_));
+  }
+
+  void operator()() const
+  {
+    handler_(arg1_, arg2_, arg3_);
+  }
+
+//private:
+  Handler handler_;
+  Arg1 arg1_;
+  Arg2 arg2_;
+  Arg3 arg3_;
+};
+
+template <typename Handler, typename Arg1, typename Arg2, typename Arg3>
+inline void* asio_handler_allocate(std::size_t size,
+    binder3<Handler, Arg1, Arg2, Arg3>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2, typename Arg3>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    binder3<Handler, Arg1, Arg2, Arg3>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2, typename Arg3>
+inline bool asio_handler_is_continuation(
+    binder3<Handler, Arg1, Arg2, Arg3>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->handler_);
+}
+
+template <typename Function, typename Handler,
+    typename Arg1, typename Arg2, typename Arg3>
+inline void asio_handler_invoke(Function& function,
+    binder3<Handler, Arg1, Arg2, Arg3>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Function, typename Handler,
+    typename Arg1, typename Arg2, typename Arg3>
+inline void asio_handler_invoke(const Function& function,
+    binder3<Handler, Arg1, Arg2, Arg3>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2, typename Arg3>
+inline binder3<typename decay<Handler>::type, Arg1, Arg2, Arg3> bind_handler(
+    ASIO_MOVE_ARG(Handler) handler, const Arg1& arg1, const Arg2& arg2,
+    const Arg3& arg3)
+{
+  return binder3<typename decay<Handler>::type, Arg1, Arg2, Arg3>(0,
+      ASIO_MOVE_CAST(Handler)(handler), arg1, arg2, arg3);
+}
+
+template <typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4>
+class binder4
+{
+public:
+  template <typename T>
+  binder4(int, ASIO_MOVE_ARG(T) handler, const Arg1& arg1,
+      const Arg2& arg2, const Arg3& arg3, const Arg4& arg4)
+    : handler_(ASIO_MOVE_CAST(T)(handler)),
+      arg1_(arg1),
+      arg2_(arg2),
+      arg3_(arg3),
+      arg4_(arg4)
+  {
+  }
+
+  binder4(Handler& handler, const Arg1& arg1,
+      const Arg2& arg2, const Arg3& arg3, const Arg4& arg4)
+    : handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      arg1_(arg1),
+      arg2_(arg2),
+      arg3_(arg3),
+      arg4_(arg4)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  binder4(const binder4& other)
+    : handler_(other.handler_),
+      arg1_(other.arg1_),
+      arg2_(other.arg2_),
+      arg3_(other.arg3_),
+      arg4_(other.arg4_)
+  {
+  }
+
+  binder4(binder4&& other)
+    : handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(other.arg1_)),
+      arg2_(ASIO_MOVE_CAST(Arg2)(other.arg2_)),
+      arg3_(ASIO_MOVE_CAST(Arg3)(other.arg3_)),
+      arg4_(ASIO_MOVE_CAST(Arg4)(other.arg4_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_), static_cast<const Arg3&>(arg3_),
+        static_cast<const Arg4&>(arg4_));
+  }
+
+  void operator()() const
+  {
+    handler_(arg1_, arg2_, arg3_, arg4_);
+  }
+
+//private:
+  Handler handler_;
+  Arg1 arg1_;
+  Arg2 arg2_;
+  Arg3 arg3_;
+  Arg4 arg4_;
+};
+
+template <typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4>
+inline void* asio_handler_allocate(std::size_t size,
+    binder4<Handler, Arg1, Arg2, Arg3, Arg4>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    binder4<Handler, Arg1, Arg2, Arg3, Arg4>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4>
+inline bool asio_handler_is_continuation(
+    binder4<Handler, Arg1, Arg2, Arg3, Arg4>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4>
+inline void asio_handler_invoke(Function& function,
+    binder4<Handler, Arg1, Arg2, Arg3, Arg4>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4>
+inline void asio_handler_invoke(const Function& function,
+    binder4<Handler, Arg1, Arg2, Arg3, Arg4>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4>
+inline binder4<typename decay<Handler>::type, Arg1, Arg2, Arg3, Arg4>
+bind_handler(ASIO_MOVE_ARG(Handler) handler, const Arg1& arg1,
+    const Arg2& arg2, const Arg3& arg3, const Arg4& arg4)
+{
+  return binder4<typename decay<Handler>::type, Arg1, Arg2, Arg3, Arg4>(0,
+      ASIO_MOVE_CAST(Handler)(handler), arg1, arg2, arg3, arg4);
+}
+
+template <typename Handler, typename Arg1, typename Arg2,
+    typename Arg3, typename Arg4, typename Arg5>
+class binder5
+{
+public:
+  template <typename T>
+  binder5(int, ASIO_MOVE_ARG(T) handler, const Arg1& arg1,
+      const Arg2& arg2, const Arg3& arg3, const Arg4& arg4, const Arg5& arg5)
+    : handler_(ASIO_MOVE_CAST(T)(handler)),
+      arg1_(arg1),
+      arg2_(arg2),
+      arg3_(arg3),
+      arg4_(arg4),
+      arg5_(arg5)
+  {
+  }
+
+  binder5(Handler& handler, const Arg1& arg1, const Arg2& arg2,
+      const Arg3& arg3, const Arg4& arg4, const Arg5& arg5)
+    : handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      arg1_(arg1),
+      arg2_(arg2),
+      arg3_(arg3),
+      arg4_(arg4),
+      arg5_(arg5)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  binder5(const binder5& other)
+    : handler_(other.handler_),
+      arg1_(other.arg1_),
+      arg2_(other.arg2_),
+      arg3_(other.arg3_),
+      arg4_(other.arg4_),
+      arg5_(other.arg5_)
+  {
+  }
+
+  binder5(binder5&& other)
+    : handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(other.arg1_)),
+      arg2_(ASIO_MOVE_CAST(Arg2)(other.arg2_)),
+      arg3_(ASIO_MOVE_CAST(Arg3)(other.arg3_)),
+      arg4_(ASIO_MOVE_CAST(Arg4)(other.arg4_)),
+      arg5_(ASIO_MOVE_CAST(Arg5)(other.arg5_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_), static_cast<const Arg3&>(arg3_),
+        static_cast<const Arg4&>(arg4_), static_cast<const Arg5&>(arg5_));
+  }
+
+  void operator()() const
+  {
+    handler_(arg1_, arg2_, arg3_, arg4_, arg5_);
+  }
+
+//private:
+  Handler handler_;
+  Arg1 arg1_;
+  Arg2 arg2_;
+  Arg3 arg3_;
+  Arg4 arg4_;
+  Arg5 arg5_;
+};
+
+template <typename Handler, typename Arg1, typename Arg2,
+    typename Arg3, typename Arg4, typename Arg5>
+inline void* asio_handler_allocate(std::size_t size,
+    binder5<Handler, Arg1, Arg2, Arg3, Arg4, Arg5>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2,
+    typename Arg3, typename Arg4, typename Arg5>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    binder5<Handler, Arg1, Arg2, Arg3, Arg4, Arg5>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2,
+    typename Arg3, typename Arg4, typename Arg5>
+inline bool asio_handler_is_continuation(
+    binder5<Handler, Arg1, Arg2, Arg3, Arg4, Arg5>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4, typename Arg5>
+inline void asio_handler_invoke(Function& function,
+    binder5<Handler, Arg1, Arg2, Arg3, Arg4, Arg5>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1,
+    typename Arg2, typename Arg3, typename Arg4, typename Arg5>
+inline void asio_handler_invoke(const Function& function,
+    binder5<Handler, Arg1, Arg2, Arg3, Arg4, Arg5>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2,
+    typename Arg3, typename Arg4, typename Arg5>
+inline binder5<typename decay<Handler>::type, Arg1, Arg2, Arg3, Arg4, Arg5>
+bind_handler(ASIO_MOVE_ARG(Handler) handler, const Arg1& arg1,
+    const Arg2& arg2, const Arg3& arg3, const Arg4& arg4, const Arg5& arg5)
+{
+  return binder5<typename decay<Handler>::type, Arg1, Arg2, Arg3, Arg4, Arg5>(0,
+      ASIO_MOVE_CAST(Handler)(handler), arg1, arg2, arg3, arg4, arg5);
+}
+
+#if defined(ASIO_HAS_MOVE)
+
+template <typename Handler, typename Arg1>
+class move_binder1
+{
+public:
+  move_binder1(int, ASIO_MOVE_ARG(Handler) handler,
+      ASIO_MOVE_ARG(Arg1) arg1)
+    : handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(arg1))
+  {
+  }
+
+  move_binder1(move_binder1&& other)
+    : handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(other.arg1_))
+  {
+  }
+
+  void operator()()
+  {
+    handler_(ASIO_MOVE_CAST(Arg1)(arg1_));
+  }
+
+//private:
+  Handler handler_;
+  Arg1 arg1_;
+};
+
+template <typename Handler, typename Arg1>
+inline void* asio_handler_allocate(std::size_t size,
+    move_binder1<Handler, Arg1>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    move_binder1<Handler, Arg1>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1>
+inline bool asio_handler_is_continuation(
+    move_binder1<Handler, Arg1>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1>
+inline void asio_handler_invoke(ASIO_MOVE_ARG(Function) function,
+    move_binder1<Handler, Arg1>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      ASIO_MOVE_CAST(Function)(function), this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2>
+class move_binder2
+{
+public:
+  move_binder2(int, ASIO_MOVE_ARG(Handler) handler,
+      const Arg1& arg1, ASIO_MOVE_ARG(Arg2) arg2)
+    : handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      arg1_(arg1),
+      arg2_(ASIO_MOVE_CAST(Arg2)(arg2))
+  {
+  }
+
+  move_binder2(move_binder2&& other)
+    : handler_(ASIO_MOVE_CAST(Handler)(other.handler_)),
+      arg1_(ASIO_MOVE_CAST(Arg1)(other.arg1_)),
+      arg2_(ASIO_MOVE_CAST(Arg2)(other.arg2_))
+  {
+  }
+
+  void operator()()
+  {
+    handler_(static_cast<const Arg1&>(arg1_),
+        ASIO_MOVE_CAST(Arg2)(arg2_));
+  }
+
+//private:
+  Handler handler_;
+  Arg1 arg1_;
+  Arg2 arg2_;
+};
+
+template <typename Handler, typename Arg1, typename Arg2>
+inline void* asio_handler_allocate(std::size_t size,
+    move_binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    move_binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler, typename Arg1, typename Arg2>
+inline bool asio_handler_is_continuation(
+    move_binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->handler_);
+}
+
+template <typename Function, typename Handler, typename Arg1, typename Arg2>
+inline void asio_handler_invoke(ASIO_MOVE_ARG(Function) function,
+    move_binder2<Handler, Arg1, Arg2>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      ASIO_MOVE_CAST(Function)(function), this_handler->handler_);
+}
+
+#endif // defined(ASIO_HAS_MOVE)
+
+} // namespace detail
+
+template <typename Handler, typename Arg1, typename Allocator>
+struct associated_allocator<detail::binder1<Handler, Arg1>, Allocator>
+{
+  typedef typename associated_allocator<Handler, Allocator>::type type;
+
+  static type get(const detail::binder1<Handler, Arg1>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<Handler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Handler, typename Arg1, typename Arg2, typename Allocator>
+struct associated_allocator<detail::binder2<Handler, Arg1, Arg2>, Allocator>
+{
+  typedef typename associated_allocator<Handler, Allocator>::type type;
+
+  static type get(const detail::binder2<Handler, Arg1, Arg2>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<Handler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Handler, typename Arg1, typename Executor>
+struct associated_executor<detail::binder1<Handler, Arg1>, Executor>
+{
+  typedef typename associated_executor<Handler, Executor>::type type;
+
+  static type get(const detail::binder1<Handler, Arg1>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<Handler, Executor>::get(h.handler_, ex);
+  }
+};
+
+template <typename Handler, typename Arg1, typename Arg2, typename Executor>
+struct associated_executor<detail::binder2<Handler, Arg1, Arg2>, Executor>
+{
+  typedef typename associated_executor<Handler, Executor>::type type;
+
+  static type get(const detail::binder2<Handler, Arg1, Arg2>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<Handler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#if defined(ASIO_HAS_MOVE)
+
+template <typename Handler, typename Arg1, typename Allocator>
+struct associated_allocator<detail::move_binder1<Handler, Arg1>, Allocator>
+{
+  typedef typename associated_allocator<Handler, Allocator>::type type;
+
+  static type get(const detail::move_binder1<Handler, Arg1>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<Handler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Handler, typename Arg1, typename Arg2, typename Allocator>
+struct associated_allocator<
+    detail::move_binder2<Handler, Arg1, Arg2>, Allocator>
+{
+  typedef typename associated_allocator<Handler, Allocator>::type type;
+
+  static type get(const detail::move_binder2<Handler, Arg1, Arg2>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<Handler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Handler, typename Arg1, typename Executor>
+struct associated_executor<detail::move_binder1<Handler, Arg1>, Executor>
+{
+  typedef typename associated_executor<Handler, Executor>::type type;
+
+  static type get(const detail::move_binder1<Handler, Arg1>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<Handler, Executor>::get(h.handler_, ex);
+  }
+};
+
+template <typename Handler, typename Arg1, typename Arg2, typename Executor>
+struct associated_executor<detail::move_binder2<Handler, Arg1, Arg2>, Executor>
+{
+  typedef typename associated_executor<Handler, Executor>::type type;
+
+  static type get(const detail::move_binder2<Handler, Arg1, Arg2>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<Handler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // defined(ASIO_HAS_MOVE)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_BIND_HANDLER_HPP
diff --git a/subprojects/asio/include/asio/detail/buffer_resize_guard.hpp b/subprojects/asio/include/asio/detail/buffer_resize_guard.hpp
new file mode 100644
index 000000000..58ebc4cc7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/buffer_resize_guard.hpp
@@ -0,0 +1,66 @@
+//
+// detail/buffer_resize_guard.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
+#define ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/limits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper class to manage buffer resizing in an exception safe way.
+template <typename Buffer>
+class buffer_resize_guard
+{
+public:
+  // Constructor.
+  buffer_resize_guard(Buffer& buffer)
+    : buffer_(buffer),
+      old_size_(buffer.size())
+  {
+  }
+
+  // Destructor rolls back the buffer resize unless commit was called.
+  ~buffer_resize_guard()
+  {
+    if (old_size_ != (std::numeric_limits<size_t>::max)())
+    {
+      buffer_.resize(old_size_);
+    }
+  }
+
+  // Commit the resize transaction.
+  void commit()
+  {
+    old_size_ = (std::numeric_limits<size_t>::max)();
+  }
+
+private:
+  // The buffer being managed.
+  Buffer& buffer_;
+
+  // The size of the buffer at the time the guard was constructed.
+  size_t old_size_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
diff --git a/subprojects/asio/include/asio/detail/buffer_sequence_adapter.hpp b/subprojects/asio/include/asio/detail/buffer_sequence_adapter.hpp
new file mode 100644
index 000000000..92a8e3d2f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/buffer_sequence_adapter.hpp
@@ -0,0 +1,544 @@
+//
+// detail/buffer_sequence_adapter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_BUFFER_SEQUENCE_ADAPTER_HPP
+#define ASIO_DETAIL_BUFFER_SEQUENCE_ADAPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/buffer.hpp"
+#include "asio/detail/array_fwd.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class buffer_sequence_adapter_base
+{
+#if defined(ASIO_WINDOWS_RUNTIME)
+public:
+  // The maximum number of buffers to support in a single operation.
+  enum { max_buffers = 1 };
+
+protected:
+  typedef Windows::Storage::Streams::IBuffer^ native_buffer_type;
+
+  ASIO_DECL static void init_native_buffer(
+      native_buffer_type& buf,
+      const asio::mutable_buffer& buffer);
+
+  ASIO_DECL static void init_native_buffer(
+      native_buffer_type& buf,
+      const asio::const_buffer& buffer);
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+public:
+  // The maximum number of buffers to support in a single operation.
+  enum { max_buffers = 64 < max_iov_len ? 64 : max_iov_len };
+
+protected:
+  typedef WSABUF native_buffer_type;
+
+  static void init_native_buffer(WSABUF& buf,
+      const asio::mutable_buffer& buffer)
+  {
+    buf.buf = static_cast<char*>(buffer.data());
+    buf.len = static_cast<ULONG>(buffer.size());
+  }
+
+  static void init_native_buffer(WSABUF& buf,
+      const asio::const_buffer& buffer)
+  {
+    buf.buf = const_cast<char*>(static_cast<const char*>(buffer.data()));
+    buf.len = static_cast<ULONG>(buffer.size());
+  }
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+public:
+  // The maximum number of buffers to support in a single operation.
+  enum { max_buffers = 64 < max_iov_len ? 64 : max_iov_len };
+
+protected:
+  typedef iovec native_buffer_type;
+
+  static void init_iov_base(void*& base, void* addr)
+  {
+    base = addr;
+  }
+
+  template <typename T>
+  static void init_iov_base(T& base, void* addr)
+  {
+    base = static_cast<T>(addr);
+  }
+
+  static void init_native_buffer(iovec& iov,
+      const asio::mutable_buffer& buffer)
+  {
+    init_iov_base(iov.iov_base, buffer.data());
+    iov.iov_len = buffer.size();
+  }
+
+  static void init_native_buffer(iovec& iov,
+      const asio::const_buffer& buffer)
+  {
+    init_iov_base(iov.iov_base, const_cast<void*>(buffer.data()));
+    iov.iov_len = buffer.size();
+  }
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+};
+
+// Helper class to translate buffers into the native buffer representation.
+template <typename Buffer, typename Buffers>
+class buffer_sequence_adapter
+  : buffer_sequence_adapter_base
+{
+public:
+  explicit buffer_sequence_adapter(const Buffers& buffer_sequence)
+    : count_(0), total_buffer_size_(0)
+  {
+    buffer_sequence_adapter::init(
+        asio::buffer_sequence_begin(buffer_sequence),
+        asio::buffer_sequence_end(buffer_sequence));
+  }
+
+  native_buffer_type* buffers()
+  {
+    return buffers_;
+  }
+
+  std::size_t count() const
+  {
+    return count_;
+  }
+
+  std::size_t total_size() const
+  {
+    return total_buffer_size_;
+  }
+
+  bool all_empty() const
+  {
+    return total_buffer_size_ == 0;
+  }
+
+  static bool all_empty(const Buffers& buffer_sequence)
+  {
+    return buffer_sequence_adapter::all_empty(
+        asio::buffer_sequence_begin(buffer_sequence),
+        asio::buffer_sequence_end(buffer_sequence));
+  }
+
+  static void validate(const Buffers& buffer_sequence)
+  {
+    buffer_sequence_adapter::validate(
+        asio::buffer_sequence_begin(buffer_sequence),
+        asio::buffer_sequence_end(buffer_sequence));
+  }
+
+  static Buffer first(const Buffers& buffer_sequence)
+  {
+    return buffer_sequence_adapter::first(
+        asio::buffer_sequence_begin(buffer_sequence),
+        asio::buffer_sequence_end(buffer_sequence));
+  }
+
+private:
+  template <typename Iterator>
+  void init(Iterator begin, Iterator end)
+  {
+    Iterator iter = begin;
+    for (; iter != end && count_ < max_buffers; ++iter, ++count_)
+    {
+      Buffer buffer(*iter);
+      init_native_buffer(buffers_[count_], buffer);
+      total_buffer_size_ += buffer.size();
+    }
+  }
+
+  template <typename Iterator>
+  static bool all_empty(Iterator begin, Iterator end)
+  {
+    Iterator iter = begin;
+    std::size_t i = 0;
+    for (; iter != end && i < max_buffers; ++iter, ++i)
+      if (Buffer(*iter).size() > 0)
+        return false;
+    return true;
+  }
+
+  template <typename Iterator>
+  static void validate(Iterator begin, Iterator end)
+  {
+    Iterator iter = begin;
+    for (; iter != end; ++iter)
+    {
+      Buffer buffer(*iter);
+      buffer.data();
+    }
+  }
+
+  template <typename Iterator>
+  static Buffer first(Iterator begin, Iterator end)
+  {
+    Iterator iter = begin;
+    for (; iter != end; ++iter)
+    {
+      Buffer buffer(*iter);
+      if (buffer.size() != 0)
+        return buffer;
+    }
+    return Buffer();
+  }
+
+  native_buffer_type buffers_[max_buffers];
+  std::size_t count_;
+  std::size_t total_buffer_size_;
+};
+
+template <typename Buffer>
+class buffer_sequence_adapter<Buffer, asio::mutable_buffer>
+  : buffer_sequence_adapter_base
+{
+public:
+  explicit buffer_sequence_adapter(
+      const asio::mutable_buffer& buffer_sequence)
+  {
+    init_native_buffer(buffer_, Buffer(buffer_sequence));
+    total_buffer_size_ = buffer_sequence.size();
+  }
+
+  native_buffer_type* buffers()
+  {
+    return &buffer_;
+  }
+
+  std::size_t count() const
+  {
+    return 1;
+  }
+
+  std::size_t total_size() const
+  {
+    return total_buffer_size_;
+  }
+
+  bool all_empty() const
+  {
+    return total_buffer_size_ == 0;
+  }
+
+  static bool all_empty(const asio::mutable_buffer& buffer_sequence)
+  {
+    return buffer_sequence.size() == 0;
+  }
+
+  static void validate(const asio::mutable_buffer& buffer_sequence)
+  {
+    buffer_sequence.data();
+  }
+
+  static Buffer first(const asio::mutable_buffer& buffer_sequence)
+  {
+    return Buffer(buffer_sequence);
+  }
+
+private:
+  native_buffer_type buffer_;
+  std::size_t total_buffer_size_;
+};
+
+template <typename Buffer>
+class buffer_sequence_adapter<Buffer, asio::const_buffer>
+  : buffer_sequence_adapter_base
+{
+public:
+  explicit buffer_sequence_adapter(
+      const asio::const_buffer& buffer_sequence)
+  {
+    init_native_buffer(buffer_, Buffer(buffer_sequence));
+    total_buffer_size_ = buffer_sequence.size();
+  }
+
+  native_buffer_type* buffers()
+  {
+    return &buffer_;
+  }
+
+  std::size_t count() const
+  {
+    return 1;
+  }
+
+  std::size_t total_size() const
+  {
+    return total_buffer_size_;
+  }
+
+  bool all_empty() const
+  {
+    return total_buffer_size_ == 0;
+  }
+
+  static bool all_empty(const asio::const_buffer& buffer_sequence)
+  {
+    return buffer_sequence.size() == 0;
+  }
+
+  static void validate(const asio::const_buffer& buffer_sequence)
+  {
+    buffer_sequence.data();
+  }
+
+  static Buffer first(const asio::const_buffer& buffer_sequence)
+  {
+    return Buffer(buffer_sequence);
+  }
+
+private:
+  native_buffer_type buffer_;
+  std::size_t total_buffer_size_;
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+template <typename Buffer>
+class buffer_sequence_adapter<Buffer, asio::mutable_buffers_1>
+  : buffer_sequence_adapter_base
+{
+public:
+  explicit buffer_sequence_adapter(
+      const asio::mutable_buffers_1& buffer_sequence)
+  {
+    init_native_buffer(buffer_, Buffer(buffer_sequence));
+    total_buffer_size_ = buffer_sequence.size();
+  }
+
+  native_buffer_type* buffers()
+  {
+    return &buffer_;
+  }
+
+  std::size_t count() const
+  {
+    return 1;
+  }
+
+  std::size_t total_size() const
+  {
+    return total_buffer_size_;
+  }
+
+  bool all_empty() const
+  {
+    return total_buffer_size_ == 0;
+  }
+
+  static bool all_empty(const asio::mutable_buffers_1& buffer_sequence)
+  {
+    return buffer_sequence.size() == 0;
+  }
+
+  static void validate(const asio::mutable_buffers_1& buffer_sequence)
+  {
+    buffer_sequence.data();
+  }
+
+  static Buffer first(const asio::mutable_buffers_1& buffer_sequence)
+  {
+    return Buffer(buffer_sequence);
+  }
+
+private:
+  native_buffer_type buffer_;
+  std::size_t total_buffer_size_;
+};
+
+template <typename Buffer>
+class buffer_sequence_adapter<Buffer, asio::const_buffers_1>
+  : buffer_sequence_adapter_base
+{
+public:
+  explicit buffer_sequence_adapter(
+      const asio::const_buffers_1& buffer_sequence)
+  {
+    init_native_buffer(buffer_, Buffer(buffer_sequence));
+    total_buffer_size_ = buffer_sequence.size();
+  }
+
+  native_buffer_type* buffers()
+  {
+    return &buffer_;
+  }
+
+  std::size_t count() const
+  {
+    return 1;
+  }
+
+  std::size_t total_size() const
+  {
+    return total_buffer_size_;
+  }
+
+  bool all_empty() const
+  {
+    return total_buffer_size_ == 0;
+  }
+
+  static bool all_empty(const asio::const_buffers_1& buffer_sequence)
+  {
+    return buffer_sequence.size() == 0;
+  }
+
+  static void validate(const asio::const_buffers_1& buffer_sequence)
+  {
+    buffer_sequence.data();
+  }
+
+  static Buffer first(const asio::const_buffers_1& buffer_sequence)
+  {
+    return Buffer(buffer_sequence);
+  }
+
+private:
+  native_buffer_type buffer_;
+  std::size_t total_buffer_size_;
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Buffer, typename Elem>
+class buffer_sequence_adapter<Buffer, boost::array<Elem, 2> >
+  : buffer_sequence_adapter_base
+{
+public:
+  explicit buffer_sequence_adapter(
+      const boost::array<Elem, 2>& buffer_sequence)
+  {
+    init_native_buffer(buffers_[0], Buffer(buffer_sequence[0]));
+    init_native_buffer(buffers_[1], Buffer(buffer_sequence[1]));
+    total_buffer_size_ = buffer_sequence[0].size() + buffer_sequence[1].size();
+  }
+
+  native_buffer_type* buffers()
+  {
+    return buffers_;
+  }
+
+  std::size_t count() const
+  {
+    return 2;
+  }
+
+  std::size_t total_size() const
+  {
+    return total_buffer_size_;
+  }
+
+  bool all_empty() const
+  {
+    return total_buffer_size_ == 0;
+  }
+
+  static bool all_empty(const boost::array<Elem, 2>& buffer_sequence)
+  {
+    return buffer_sequence[0].size() == 0 && buffer_sequence[1].size() == 0;
+  }
+
+  static void validate(const boost::array<Elem, 2>& buffer_sequence)
+  {
+    buffer_sequence[0].data();
+    buffer_sequence[1].data();
+  }
+
+  static Buffer first(const boost::array<Elem, 2>& buffer_sequence)
+  {
+    return Buffer(buffer_sequence[0].size() != 0
+        ? buffer_sequence[0] : buffer_sequence[1]);
+  }
+
+private:
+  native_buffer_type buffers_[2];
+  std::size_t total_buffer_size_;
+};
+
+#if defined(ASIO_HAS_STD_ARRAY)
+
+template <typename Buffer, typename Elem>
+class buffer_sequence_adapter<Buffer, std::array<Elem, 2> >
+  : buffer_sequence_adapter_base
+{
+public:
+  explicit buffer_sequence_adapter(
+      const std::array<Elem, 2>& buffer_sequence)
+  {
+    init_native_buffer(buffers_[0], Buffer(buffer_sequence[0]));
+    init_native_buffer(buffers_[1], Buffer(buffer_sequence[1]));
+    total_buffer_size_ = buffer_sequence[0].size() + buffer_sequence[1].size();
+  }
+
+  native_buffer_type* buffers()
+  {
+    return buffers_;
+  }
+
+  std::size_t count() const
+  {
+    return 2;
+  }
+
+  std::size_t total_size() const
+  {
+    return total_buffer_size_;
+  }
+
+  bool all_empty() const
+  {
+    return total_buffer_size_ == 0;
+  }
+
+  static bool all_empty(const std::array<Elem, 2>& buffer_sequence)
+  {
+    return buffer_sequence[0].size() == 0 && buffer_sequence[1].size() == 0;
+  }
+
+  static void validate(const std::array<Elem, 2>& buffer_sequence)
+  {
+    buffer_sequence[0].data();
+    buffer_sequence[1].data();
+  }
+
+  static Buffer first(const std::array<Elem, 2>& buffer_sequence)
+  {
+    return Buffer(buffer_sequence[0].size() != 0
+        ? buffer_sequence[0] : buffer_sequence[1]);
+  }
+
+private:
+  native_buffer_type buffers_[2];
+  std::size_t total_buffer_size_;
+};
+
+#endif // defined(ASIO_HAS_STD_ARRAY)
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/buffer_sequence_adapter.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_BUFFER_SEQUENCE_ADAPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/buffered_stream_storage.hpp b/subprojects/asio/include/asio/detail/buffered_stream_storage.hpp
new file mode 100644
index 000000000..c5eb081d9
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/buffered_stream_storage.hpp
@@ -0,0 +1,126 @@
+//
+// detail/buffered_stream_storage.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_BUFFERED_STREAM_STORAGE_HPP
+#define ASIO_DETAIL_BUFFERED_STREAM_STORAGE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/buffer.hpp"
+#include "asio/detail/assert.hpp"
+#include <cstddef>
+#include <cstring>
+#include <vector>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class buffered_stream_storage
+{
+public:
+  // The type of the bytes stored in the buffer.
+  typedef unsigned char byte_type;
+
+  // The type used for offsets into the buffer.
+  typedef std::size_t size_type;
+
+  // Constructor.
+  explicit buffered_stream_storage(std::size_t buffer_capacity)
+    : begin_offset_(0),
+      end_offset_(0),
+      buffer_(buffer_capacity)
+  {
+  }
+
+  /// Clear the buffer.
+  void clear()
+  {
+    begin_offset_ = 0;
+    end_offset_ = 0;
+  }
+
+  // Return a pointer to the beginning of the unread data.
+  mutable_buffer data()
+  {
+    return asio::buffer(buffer_) + begin_offset_;
+  }
+
+  // Return a pointer to the beginning of the unread data.
+  const_buffer data() const
+  {
+    return asio::buffer(buffer_) + begin_offset_;
+  }
+
+  // Is there no unread data in the buffer.
+  bool empty() const
+  {
+    return begin_offset_ == end_offset_;
+  }
+
+  // Return the amount of unread data the is in the buffer.
+  size_type size() const
+  {
+    return end_offset_ - begin_offset_;
+  }
+
+  // Resize the buffer to the specified length.
+  void resize(size_type length)
+  {
+    ASIO_ASSERT(length <= capacity());
+    if (begin_offset_ + length <= capacity())
+    {
+      end_offset_ = begin_offset_ + length;
+    }
+    else
+    {
+      using namespace std; // For memmove.
+      memmove(&buffer_[0], &buffer_[0] + begin_offset_, size());
+      end_offset_ = length;
+      begin_offset_ = 0;
+    }
+  }
+
+  // Return the maximum size for data in the buffer.
+  size_type capacity() const
+  {
+    return buffer_.size();
+  }
+
+  // Consume multiple bytes from the beginning of the buffer.
+  void consume(size_type count)
+  {
+    ASIO_ASSERT(begin_offset_ + count <= end_offset_);
+    begin_offset_ += count;
+    if (empty())
+      clear();
+  }
+
+private:
+  // The offset to the beginning of the unread data.
+  size_type begin_offset_;
+
+  // The offset to the end of the unread data.
+  size_type end_offset_;
+  
+  // The data in the buffer.
+  std::vector<byte_type> buffer_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_BUFFERED_STREAM_STORAGE_HPP
diff --git a/subprojects/asio/include/asio/detail/call_stack.hpp b/subprojects/asio/include/asio/detail/call_stack.hpp
new file mode 100644
index 000000000..5725a10a2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/call_stack.hpp
@@ -0,0 +1,125 @@
+//
+// detail/call_stack.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CALL_STACK_HPP
+#define ASIO_DETAIL_CALL_STACK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/tss_ptr.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper class to determine whether or not the current thread is inside an
+// invocation of io_context::run() for a specified io_context object.
+template <typename Key, typename Value = unsigned char>
+class call_stack
+{
+public:
+  // Context class automatically pushes the key/value pair on to the stack.
+  class context
+    : private noncopyable
+  {
+  public:
+    // Push the key on to the stack.
+    explicit context(Key* k)
+      : key_(k),
+        next_(call_stack<Key, Value>::top_)
+    {
+      value_ = reinterpret_cast<unsigned char*>(this);
+      call_stack<Key, Value>::top_ = this;
+    }
+
+    // Push the key/value pair on to the stack.
+    context(Key* k, Value& v)
+      : key_(k),
+        value_(&v),
+        next_(call_stack<Key, Value>::top_)
+    {
+      call_stack<Key, Value>::top_ = this;
+    }
+
+    // Pop the key/value pair from the stack.
+    ~context()
+    {
+      call_stack<Key, Value>::top_ = next_;
+    }
+
+    // Find the next context with the same key.
+    Value* next_by_key() const
+    {
+      context* elem = next_;
+      while (elem)
+      {
+        if (elem->key_ == key_)
+          return elem->value_;
+        elem = elem->next_;
+      }
+      return 0;
+    }
+
+  private:
+    friend class call_stack<Key, Value>;
+
+    // The key associated with the context.
+    Key* key_;
+
+    // The value associated with the context.
+    Value* value_;
+
+    // The next element in the stack.
+    context* next_;
+  };
+
+  friend class context;
+
+  // Determine whether the specified owner is on the stack. Returns address of
+  // key if present, 0 otherwise.
+  static Value* contains(Key* k)
+  {
+    context* elem = top_;
+    while (elem)
+    {
+      if (elem->key_ == k)
+        return elem->value_;
+      elem = elem->next_;
+    }
+    return 0;
+  }
+
+  // Obtain the value at the top of the stack.
+  static Value* top()
+  {
+    context* elem = top_;
+    return elem ? elem->value_ : 0;
+  }
+
+private:
+  // The top of the stack of calls for the current thread.
+  static tss_ptr<context> top_;
+};
+
+template <typename Key, typename Value>
+tss_ptr<typename call_stack<Key, Value>::context>
+call_stack<Key, Value>::top_;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_CALL_STACK_HPP
diff --git a/subprojects/asio/include/asio/detail/chrono.hpp b/subprojects/asio/include/asio/detail/chrono.hpp
new file mode 100644
index 000000000..8f56beed5
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/chrono.hpp
@@ -0,0 +1,66 @@
+//
+// detail/chrono.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CHRONO_HPP
+#define ASIO_DETAIL_CHRONO_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_CHRONO)
+# include <chrono>
+#elif defined(ASIO_HAS_BOOST_CHRONO)
+# include <boost/chrono/system_clocks.hpp>
+#endif // defined(ASIO_HAS_BOOST_CHRONO)
+
+namespace asio {
+namespace chrono {
+
+#if defined(ASIO_HAS_STD_CHRONO)
+using std::chrono::duration;
+using std::chrono::time_point;
+using std::chrono::duration_cast;
+using std::chrono::nanoseconds;
+using std::chrono::microseconds;
+using std::chrono::milliseconds;
+using std::chrono::seconds;
+using std::chrono::minutes;
+using std::chrono::hours;
+using std::chrono::time_point_cast;
+#if defined(ASIO_HAS_STD_CHRONO_MONOTONIC_CLOCK)
+typedef std::chrono::monotonic_clock steady_clock;
+#else // defined(ASIO_HAS_STD_CHRONO_MONOTONIC_CLOCK)
+using std::chrono::steady_clock;
+#endif // defined(ASIO_HAS_STD_CHRONO_MONOTONIC_CLOCK)
+using std::chrono::system_clock;
+using std::chrono::high_resolution_clock;
+#elif defined(ASIO_HAS_BOOST_CHRONO)
+using boost::chrono::duration;
+using boost::chrono::time_point;
+using boost::chrono::duration_cast;
+using boost::chrono::nanoseconds;
+using boost::chrono::microseconds;
+using boost::chrono::milliseconds;
+using boost::chrono::seconds;
+using boost::chrono::minutes;
+using boost::chrono::hours;
+using boost::chrono::time_point_cast;
+using boost::chrono::system_clock;
+using boost::chrono::steady_clock;
+using boost::chrono::high_resolution_clock;
+#endif // defined(ASIO_HAS_BOOST_CHRONO)
+
+} // namespace chrono
+} // namespace asio
+
+#endif // ASIO_DETAIL_CHRONO_HPP
diff --git a/subprojects/asio/include/asio/detail/chrono_time_traits.hpp b/subprojects/asio/include/asio/detail/chrono_time_traits.hpp
new file mode 100644
index 000000000..d1528f70d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/chrono_time_traits.hpp
@@ -0,0 +1,190 @@
+//
+// detail/chrono_time_traits.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CHRONO_TIME_TRAITS_HPP
+#define ASIO_DETAIL_CHRONO_TIME_TRAITS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/cstdint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper template to compute the greatest common divisor.
+template <int64_t v1, int64_t v2>
+struct gcd { enum { value = gcd<v2, v1 % v2>::value }; };
+
+template <int64_t v1>
+struct gcd<v1, 0> { enum { value = v1 }; };
+
+// Adapts std::chrono clocks for use with a deadline timer.
+template <typename Clock, typename WaitTraits>
+struct chrono_time_traits
+{
+  // The clock type.
+  typedef Clock clock_type;
+
+  // The duration type of the clock.
+  typedef typename clock_type::duration duration_type;
+
+  // The time point type of the clock.
+  typedef typename clock_type::time_point time_type;
+
+  // The period of the clock.
+  typedef typename duration_type::period period_type;
+
+  // Get the current time.
+  static time_type now()
+  {
+    return clock_type::now();
+  }
+
+  // Add a duration to a time.
+  static time_type add(const time_type& t, const duration_type& d)
+  {
+    const time_type epoch;
+    if (t >= epoch)
+    {
+      if ((time_type::max)() - t < d)
+        return (time_type::max)();
+    }
+    else // t < epoch
+    {
+      if (-(t - (time_type::min)()) > d)
+        return (time_type::min)();
+    }
+
+    return t + d;
+  }
+
+  // Subtract one time from another.
+  static duration_type subtract(const time_type& t1, const time_type& t2)
+  {
+    const time_type epoch;
+    if (t1 >= epoch)
+    {
+      if (t2 >= epoch)
+      {
+        return t1 - t2;
+      }
+      else if (t2 == (time_type::min)())
+      {
+        return (duration_type::max)();
+      }
+      else if ((time_type::max)() - t1 < epoch - t2)
+      {
+        return (duration_type::max)();
+      }
+      else
+      {
+        return t1 - t2;
+      }
+    }
+    else // t1 < epoch
+    {
+      if (t2 < epoch)
+      {
+        return t1 - t2;
+      }
+      else if (t1 == (time_type::min)())
+      {
+        return (duration_type::min)();
+      }
+      else if ((time_type::max)() - t2 < epoch - t1)
+      {
+        return (duration_type::min)();
+      }
+      else
+      {
+        return -(t2 - t1);
+      }
+    }
+  }
+
+  // Test whether one time is less than another.
+  static bool less_than(const time_type& t1, const time_type& t2)
+  {
+    return t1 < t2;
+  }
+
+  // Implement just enough of the posix_time::time_duration interface to supply
+  // what the timer_queue requires.
+  class posix_time_duration
+  {
+  public:
+    explicit posix_time_duration(const duration_type& d)
+      : d_(d)
+    {
+    }
+
+    int64_t ticks() const
+    {
+      return d_.count();
+    }
+
+    int64_t total_seconds() const
+    {
+      return duration_cast<1, 1>();
+    }
+
+    int64_t total_milliseconds() const
+    {
+      return duration_cast<1, 1000>();
+    }
+
+    int64_t total_microseconds() const
+    {
+      return duration_cast<1, 1000000>();
+    }
+
+  private:
+    template <int64_t Num, int64_t Den>
+    int64_t duration_cast() const
+    {
+      const int64_t num1 = period_type::num / gcd<period_type::num, Num>::value;
+      const int64_t num2 = Num / gcd<period_type::num, Num>::value;
+
+      const int64_t den1 = period_type::den / gcd<period_type::den, Den>::value;
+      const int64_t den2 = Den / gcd<period_type::den, Den>::value;
+
+      const int64_t num = num1 * den2;
+      const int64_t den = num2 * den1;
+
+      if (num == 1 && den == 1)
+        return ticks();
+      else if (num != 1 && den == 1)
+        return ticks() * num;
+      else if (num == 1 && period_type::den != 1)
+        return ticks() / den;
+      else
+        return ticks() * num / den;
+    }
+
+    duration_type d_;
+  };
+
+  // Convert to POSIX duration type.
+  static posix_time_duration to_posix_duration(const duration_type& d)
+  {
+    return posix_time_duration(WaitTraits::to_wait_duration(d));
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_CHRONO_TIME_TRAITS_HPP
diff --git a/subprojects/asio/include/asio/detail/completion_handler.hpp b/subprojects/asio/include/asio/detail/completion_handler.hpp
new file mode 100644
index 000000000..58a2e6db9
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/completion_handler.hpp
@@ -0,0 +1,83 @@
+//
+// detail/completion_handler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_COMPLETION_HANDLER_HPP
+#define ASIO_DETAIL_COMPLETION_HANDLER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_work.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class completion_handler : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(completion_handler);
+
+  completion_handler(Handler& h)
+    : operation(&completion_handler::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(h))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    completion_handler* h(static_cast<completion_handler*>(base));
+    ptr p = { asio::detail::addressof(h->handler_), h, h };
+    handler_work<Handler> w(h->handler_);
+
+    ASIO_HANDLER_COMPLETION((*h));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    Handler handler(ASIO_MOVE_CAST(Handler)(h->handler_));
+    p.h = asio::detail::addressof(handler);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN(());
+      w.complete(handler, handler);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_COMPLETION_HANDLER_HPP
diff --git a/subprojects/asio/include/asio/detail/concurrency_hint.hpp b/subprojects/asio/include/asio/detail/concurrency_hint.hpp
new file mode 100644
index 000000000..229124d37
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/concurrency_hint.hpp
@@ -0,0 +1,94 @@
+//
+// detail/concurrency_hint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CONCURRENCY_HINT_HPP
+#define ASIO_DETAIL_CONCURRENCY_HINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+
+// The concurrency hint ID and mask are used to identify when a "well-known"
+// concurrency hint value has been passed to the io_context.
+#define ASIO_CONCURRENCY_HINT_ID 0xA5100000u
+#define ASIO_CONCURRENCY_HINT_ID_MASK 0xFFFF0000u
+
+// If set, this bit indicates that the scheduler should perform locking.
+#define ASIO_CONCURRENCY_HINT_LOCKING_SCHEDULER 0x1u
+
+// If set, this bit indicates that the reactor should perform locking when
+// managing descriptor registrations.
+#define ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_REGISTRATION 0x2u
+
+// If set, this bit indicates that the reactor should perform locking for I/O.
+#define ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_IO 0x4u
+
+// Helper macro to determine if we have a special concurrency hint.
+#define ASIO_CONCURRENCY_HINT_IS_SPECIAL(hint) \
+  ((static_cast<unsigned>(hint) \
+    & ASIO_CONCURRENCY_HINT_ID_MASK) \
+      == ASIO_CONCURRENCY_HINT_ID)
+
+// Helper macro to determine if locking is enabled for a given facility.
+#define ASIO_CONCURRENCY_HINT_IS_LOCKING(facility, hint) \
+  (((static_cast<unsigned>(hint) \
+    & (ASIO_CONCURRENCY_HINT_ID_MASK \
+      | ASIO_CONCURRENCY_HINT_LOCKING_ ## facility)) \
+        ^ ASIO_CONCURRENCY_HINT_ID) != 0)
+
+// This special concurrency hint disables locking in both the scheduler and
+// reactor I/O. This hint has the following restrictions:
+//
+// - Care must be taken to ensure that all operations on the io_context and any
+//   of its associated I/O objects (such as sockets and timers) occur in only
+//   one thread at a time.
+//
+// - Asynchronous resolve operations fail with operation_not_supported.
+//
+// - If a signal_set is used with the io_context, signal_set objects cannot be
+//   used with any other io_context in the program.
+#define ASIO_CONCURRENCY_HINT_UNSAFE \
+  static_cast<int>(ASIO_CONCURRENCY_HINT_ID)
+
+// This special concurrency hint disables locking in the reactor I/O. This hint
+// has the following restrictions:
+//
+// - Care must be taken to ensure that run functions on the io_context, and all
+//   operations on the io_context's associated I/O objects (such as sockets and
+//   timers), occur in only one thread at a time.
+#define ASIO_CONCURRENCY_HINT_UNSAFE_IO \
+  static_cast<int>(ASIO_CONCURRENCY_HINT_ID \
+      | ASIO_CONCURRENCY_HINT_LOCKING_SCHEDULER \
+      | ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_REGISTRATION)
+
+// The special concurrency hint provides full thread safety.
+#define ASIO_CONCURRENCY_HINT_SAFE \
+  static_cast<int>(ASIO_CONCURRENCY_HINT_ID \
+      | ASIO_CONCURRENCY_HINT_LOCKING_SCHEDULER \
+      | ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_REGISTRATION \
+      | ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_IO)
+
+// This #define may be overridden at compile time to specify a program-wide
+// default concurrency hint, used by the zero-argument io_context constructor.
+#if !defined(ASIO_CONCURRENCY_HINT_DEFAULT)
+# define ASIO_CONCURRENCY_HINT_DEFAULT -1
+#endif // !defined(ASIO_CONCURRENCY_HINT_DEFAULT)
+
+// This #define may be overridden at compile time to specify a program-wide
+// concurrency hint, used by the one-argument io_context constructor when
+// passed a value of 1.
+#if !defined(ASIO_CONCURRENCY_HINT_1)
+# define ASIO_CONCURRENCY_HINT_1 1
+#endif // !defined(ASIO_CONCURRENCY_HINT_DEFAULT)
+
+#endif // ASIO_DETAIL_CONCURRENCY_HINT_HPP
diff --git a/subprojects/asio/include/asio/detail/conditionally_enabled_event.hpp b/subprojects/asio/include/asio/detail/conditionally_enabled_event.hpp
new file mode 100644
index 000000000..0fda401e3
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/conditionally_enabled_event.hpp
@@ -0,0 +1,112 @@
+//
+// detail/conditionally_enabled_event.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CONDITIONALLY_ENABLED_EVENT_HPP
+#define ASIO_DETAIL_CONDITIONALLY_ENABLED_EVENT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/conditionally_enabled_mutex.hpp"
+#include "asio/detail/event.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/null_event.hpp"
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Mutex adapter used to conditionally enable or disable locking.
+class conditionally_enabled_event
+  : private noncopyable
+{
+public:
+  // Constructor.
+  conditionally_enabled_event()
+  {
+  }
+
+  // Destructor.
+  ~conditionally_enabled_event()
+  {
+  }
+
+  // Signal the event. (Retained for backward compatibility.)
+  void signal(conditionally_enabled_mutex::scoped_lock& lock)
+  {
+    if (lock.mutex_.enabled_)
+      event_.signal(lock);
+  }
+
+  // Signal all waiters.
+  void signal_all(conditionally_enabled_mutex::scoped_lock& lock)
+  {
+    if (lock.mutex_.enabled_)
+      event_.signal_all(lock);
+  }
+
+  // Unlock the mutex and signal one waiter.
+  void unlock_and_signal_one(
+      conditionally_enabled_mutex::scoped_lock& lock)
+  {
+    if (lock.mutex_.enabled_)
+      event_.unlock_and_signal_one(lock);
+  }
+
+  // If there's a waiter, unlock the mutex and signal it.
+  bool maybe_unlock_and_signal_one(
+      conditionally_enabled_mutex::scoped_lock& lock)
+  {
+    if (lock.mutex_.enabled_)
+      return event_.maybe_unlock_and_signal_one(lock);
+    else
+      return false;
+  }
+
+  // Reset the event.
+  void clear(conditionally_enabled_mutex::scoped_lock& lock)
+  {
+    if (lock.mutex_.enabled_)
+      event_.clear(lock);
+  }
+
+  // Wait for the event to become signalled.
+  void wait(conditionally_enabled_mutex::scoped_lock& lock)
+  {
+    if (lock.mutex_.enabled_)
+      event_.wait(lock);
+    else
+      null_event().wait(lock);
+  }
+
+  // Timed wait for the event to become signalled.
+  bool wait_for_usec(
+      conditionally_enabled_mutex::scoped_lock& lock, long usec)
+  {
+    if (lock.mutex_.enabled_)
+      return event_.wait_for_usec(lock, usec);
+    else
+      return null_event().wait_for_usec(lock, usec);
+  }
+
+private:
+  asio::detail::event event_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_CONDITIONALLY_ENABLED_EVENT_HPP
diff --git a/subprojects/asio/include/asio/detail/conditionally_enabled_mutex.hpp b/subprojects/asio/include/asio/detail/conditionally_enabled_mutex.hpp
new file mode 100644
index 000000000..2872db98b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/conditionally_enabled_mutex.hpp
@@ -0,0 +1,149 @@
+//
+// detail/conditionally_enabled_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CONDITIONALLY_ENABLED_MUTEX_HPP
+#define ASIO_DETAIL_CONDITIONALLY_ENABLED_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Mutex adapter used to conditionally enable or disable locking.
+class conditionally_enabled_mutex
+  : private noncopyable
+{
+public:
+  // Helper class to lock and unlock a mutex automatically.
+  class scoped_lock
+    : private noncopyable
+  {
+  public:
+    // Tag type used to distinguish constructors.
+    enum adopt_lock_t { adopt_lock };
+
+    // Constructor adopts a lock that is already held.
+    scoped_lock(conditionally_enabled_mutex& m, adopt_lock_t)
+      : mutex_(m),
+        locked_(m.enabled_)
+    {
+    }
+
+    // Constructor acquires the lock.
+    explicit scoped_lock(conditionally_enabled_mutex& m)
+      : mutex_(m)
+    {
+      if (m.enabled_)
+      {
+        mutex_.mutex_.lock();
+        locked_ = true;
+      }
+      else
+        locked_ = false;
+    }
+
+    // Destructor releases the lock.
+    ~scoped_lock()
+    {
+      if (locked_)
+        mutex_.mutex_.unlock();
+    }
+
+    // Explicitly acquire the lock.
+    void lock()
+    {
+      if (mutex_.enabled_ && !locked_)
+      {
+        mutex_.mutex_.lock();
+        locked_ = true;
+      }
+    }
+
+    // Explicitly release the lock.
+    void unlock()
+    {
+      if (locked_)
+      {
+        mutex_.unlock();
+        locked_ = false;
+      }
+    }
+
+    // Test whether the lock is held.
+    bool locked() const
+    {
+      return locked_;
+    }
+
+    // Get the underlying mutex.
+    asio::detail::mutex& mutex()
+    {
+      return mutex_.mutex_;
+    }
+
+  private:
+    friend class conditionally_enabled_event;
+    conditionally_enabled_mutex& mutex_;
+    bool locked_;
+  };
+
+  // Constructor.
+  explicit conditionally_enabled_mutex(bool enabled)
+    : enabled_(enabled)
+  {
+  }
+
+  // Destructor.
+  ~conditionally_enabled_mutex()
+  {
+  }
+
+  // Determine whether locking is enabled.
+  bool enabled() const
+  {
+    return enabled_;
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+    if (enabled_)
+      mutex_.lock();
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+    if (enabled_)
+      mutex_.unlock();
+  }
+
+private:
+  friend class scoped_lock;
+  friend class conditionally_enabled_event;
+  asio::detail::mutex mutex_;
+  const bool enabled_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_CONDITIONALLY_ENABLED_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/config.hpp b/subprojects/asio/include/asio/detail/config.hpp
new file mode 100644
index 000000000..e54eea744
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/config.hpp
@@ -0,0 +1,1456 @@
+//
+// detail/config.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CONFIG_HPP
+#define ASIO_DETAIL_CONFIG_HPP
+
+#if defined(ASIO_STANDALONE)
+# define ASIO_DISABLE_BOOST_ARRAY 1
+# define ASIO_DISABLE_BOOST_ASSERT 1
+# define ASIO_DISABLE_BOOST_BIND 1
+# define ASIO_DISABLE_BOOST_CHRONO 1
+# define ASIO_DISABLE_BOOST_DATE_TIME 1
+# define ASIO_DISABLE_BOOST_LIMITS 1
+# define ASIO_DISABLE_BOOST_REGEX 1
+# define ASIO_DISABLE_BOOST_STATIC_CONSTANT 1
+# define ASIO_DISABLE_BOOST_THROW_EXCEPTION 1
+# define ASIO_DISABLE_BOOST_WORKAROUND 1
+#else // defined(ASIO_STANDALONE)
+# include <boost/config.hpp>
+# include <boost/version.hpp>
+# define ASIO_HAS_BOOST_CONFIG 1
+#endif // defined(ASIO_STANDALONE)
+
+// Default to a header-only implementation. The user must specifically request
+// separate compilation by defining either ASIO_SEPARATE_COMPILATION or
+// ASIO_DYN_LINK (as a DLL/shared library implies separate compilation).
+#if !defined(ASIO_HEADER_ONLY)
+# if !defined(ASIO_SEPARATE_COMPILATION)
+#  if !defined(ASIO_DYN_LINK)
+#   define ASIO_HEADER_ONLY 1
+#  endif // !defined(ASIO_DYN_LINK)
+# endif // !defined(ASIO_SEPARATE_COMPILATION)
+#endif // !defined(ASIO_HEADER_ONLY)
+
+#if defined(ASIO_HEADER_ONLY)
+# define ASIO_DECL inline
+#else // defined(ASIO_HEADER_ONLY)
+# if defined(_MSC_VER) || defined(__BORLANDC__) || defined(__CODEGEARC__)
+// We need to import/export our code only if the user has specifically asked
+// for it by defining ASIO_DYN_LINK.
+#  if defined(ASIO_DYN_LINK)
+// Export if this is our own source, otherwise import.
+#   if defined(ASIO_SOURCE)
+#    define ASIO_DECL __declspec(dllexport)
+#   else // defined(ASIO_SOURCE)
+#    define ASIO_DECL __declspec(dllimport)
+#   endif // defined(ASIO_SOURCE)
+#  endif // defined(ASIO_DYN_LINK)
+# endif // defined(_MSC_VER) || defined(__BORLANDC__) || defined(__CODEGEARC__)
+#endif // defined(ASIO_HEADER_ONLY)
+
+// If ASIO_DECL isn't defined yet define it now.
+#if !defined(ASIO_DECL)
+# define ASIO_DECL
+#endif // !defined(ASIO_DECL)
+
+// Microsoft Visual C++ detection.
+#if !defined(ASIO_MSVC)
+# if defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_MSVC)
+#  define ASIO_MSVC BOOST_MSVC
+# elif defined(_MSC_VER) && (defined(__INTELLISENSE__) \
+      || (!defined(__MWERKS__) && !defined(__EDG_VERSION__)))
+#  define ASIO_MSVC _MSC_VER
+# endif // defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_MSVC)
+#endif // !defined(ASIO_MSVC)
+
+// Clang / libc++ detection.
+#if defined(__clang__)
+# if (__cplusplus >= 201103)
+#  if __has_include(<__config>)
+#   include <__config>
+#   if defined(_LIBCPP_VERSION)
+#    define ASIO_HAS_CLANG_LIBCXX 1
+#   endif // defined(_LIBCPP_VERSION)
+#  endif // __has_include(<__config>)
+# endif // (__cplusplus >= 201103)
+#endif // defined(__clang__)
+
+// Android platform detection.
+#if defined(__ANDROID__)
+# include <android/api-level.h>
+#endif // defined(__ANDROID__)
+
+// Support move construction and assignment on compilers known to allow it.
+#if !defined(ASIO_HAS_MOVE)
+# if !defined(ASIO_DISABLE_MOVE)
+#  if defined(__clang__)
+#   if __has_feature(__cxx_rvalue_references__)
+#    define ASIO_HAS_MOVE 1
+#   endif // __has_feature(__cxx_rvalue_references__)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_MOVE 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_MOVE 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+#  if defined(__INTEL_CXX11_MODE__)
+#    if defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 1500)
+#      define BOOST_ASIO_HAS_MOVE 1
+#    endif // defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 1500)
+#    if defined(__ICL) && (__ICL >= 1500)
+#      define BOOST_ASIO_HAS_MOVE 1
+#    endif // defined(__ICL) && (__ICL >= 1500)
+#  endif // defined(__INTEL_CXX11_MODE__)
+# endif // !defined(ASIO_DISABLE_MOVE)
+#endif // !defined(ASIO_HAS_MOVE)
+
+// If ASIO_MOVE_CAST isn't defined, and move support is available, define
+// ASIO_MOVE_ARG and ASIO_MOVE_CAST to take advantage of rvalue
+// references and perfect forwarding.
+#if defined(ASIO_HAS_MOVE) && !defined(ASIO_MOVE_CAST)
+# define ASIO_MOVE_ARG(type) type&&
+# define ASIO_MOVE_ARG2(type1, type2) type1, type2&&
+# define ASIO_MOVE_CAST(type) static_cast<type&&>
+# define ASIO_MOVE_CAST2(type1, type2) static_cast<type1, type2&&>
+#endif // defined(ASIO_HAS_MOVE) && !defined(ASIO_MOVE_CAST)
+
+// If ASIO_MOVE_CAST still isn't defined, default to a C++03-compatible
+// implementation. Note that older g++ and MSVC versions don't like it when you
+// pass a non-member function through a const reference, so for most compilers
+// we'll play it safe and stick with the old approach of passing the handler by
+// value.
+#if !defined(ASIO_MOVE_CAST)
+# if defined(__GNUC__)
+#  if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 1)) || (__GNUC__ > 4)
+#   define ASIO_MOVE_ARG(type) const type&
+#  else // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 1)) || (__GNUC__ > 4)
+#   define ASIO_MOVE_ARG(type) type
+#  endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 1)) || (__GNUC__ > 4)
+# elif defined(ASIO_MSVC)
+#  if (_MSC_VER >= 1400)
+#   define ASIO_MOVE_ARG(type) const type&
+#  else // (_MSC_VER >= 1400)
+#   define ASIO_MOVE_ARG(type) type
+#  endif // (_MSC_VER >= 1400)
+# else
+#  define ASIO_MOVE_ARG(type) type
+# endif
+# define ASIO_MOVE_CAST(type) static_cast<const type&>
+# define ASIO_MOVE_CAST2(type1, type2) static_cast<const type1, type2&>
+#endif // !defined(ASIO_MOVE_CAST)
+
+// Support variadic templates on compilers known to allow it.
+#if !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+# if !defined(ASIO_DISABLE_VARIADIC_TEMPLATES)
+#  if defined(__clang__)
+#   if __has_feature(__cxx_variadic_templates__)
+#    define ASIO_HAS_VARIADIC_TEMPLATES 1
+#   endif // __has_feature(__cxx_variadic_templates__)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_VARIADIC_TEMPLATES 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1900)
+#    define ASIO_HAS_VARIADIC_TEMPLATES 1
+#   endif // (_MSC_VER >= 1900)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_VARIADIC_TEMPLATES)
+#endif // !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+// Support deleted functions on compilers known to allow it.
+#if !defined(ASIO_DELETED)
+# if defined(__GNUC__)
+#  if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#   if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#    define ASIO_DELETED = delete
+#   endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+# endif // defined(__GNUC__)
+# if defined(__clang__)
+#  if __has_feature(__cxx_deleted_functions__)
+#   define ASIO_DELETED = delete
+#  endif // __has_feature(__cxx_deleted_functions__)
+# endif // defined(__clang__)
+# if defined(ASIO_MSVC)
+#  if (_MSC_VER >= 1900)
+#   define ASIO_DELETED = delete
+#  endif // (_MSC_VER >= 1900)
+# endif // defined(ASIO_MSVC)
+# if !defined(ASIO_DELETED)
+#  define ASIO_DELETED
+# endif // !defined(ASIO_DELETED)
+#endif // !defined(ASIO_DELETED)
+
+// Support constexpr on compilers known to allow it.
+#if !defined(ASIO_HAS_CONSTEXPR)
+# if !defined(ASIO_DISABLE_CONSTEXPR)
+#  if defined(__clang__)
+#   if __has_feature(__cxx_constexpr__)
+#    define ASIO_HAS_CONSTEXPR 1
+#   endif // __has_feature(__cxx_constexr__)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_CONSTEXPR 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1900)
+#    define ASIO_HAS_CONSTEXPR 1
+#   endif // (_MSC_VER >= 1900)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_CONSTEXPR)
+#endif // !defined(ASIO_HAS_CONSTEXPR)
+#if !defined(ASIO_CONSTEXPR)
+# if defined(ASIO_HAS_CONSTEXPR)
+#  define ASIO_CONSTEXPR constexpr
+# else // defined(ASIO_HAS_CONSTEXPR)
+#  define ASIO_CONSTEXPR
+# endif // defined(ASIO_HAS_CONSTEXPR)
+#endif // !defined(ASIO_CONSTEXPR)
+
+// Support noexcept on compilers known to allow it.
+#if !defined(ASIO_NOEXCEPT)
+# if !defined(ASIO_DISABLE_NOEXCEPT)
+#  if defined(ASIO_HAS_BOOST_CONFIG) && (BOOST_VERSION >= 105300)
+#   define ASIO_NOEXCEPT BOOST_NOEXCEPT
+#   define ASIO_NOEXCEPT_OR_NOTHROW BOOST_NOEXCEPT_OR_NOTHROW
+#  elif defined(__clang__)
+#   if __has_feature(__cxx_noexcept__)
+#    define ASIO_NOEXCEPT noexcept(true)
+#    define ASIO_NOEXCEPT_OR_NOTHROW noexcept(true)
+#   endif // __has_feature(__cxx_noexcept__)
+#  elif defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#      define ASIO_NOEXCEPT noexcept(true)
+#      define ASIO_NOEXCEPT_OR_NOTHROW noexcept(true)
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  elif defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1900)
+#    define ASIO_NOEXCEPT noexcept(true)
+#    define ASIO_NOEXCEPT_OR_NOTHROW noexcept(true)
+#   endif // (_MSC_VER >= 1900)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_NOEXCEPT)
+# if !defined(ASIO_NOEXCEPT)
+#  define ASIO_NOEXCEPT
+# endif // !defined(ASIO_NOEXCEPT)
+# if !defined(ASIO_NOEXCEPT_OR_NOTHROW)
+#  define ASIO_NOEXCEPT_OR_NOTHROW throw()
+# endif // !defined(ASIO_NOEXCEPT_OR_NOTHROW)
+#endif // !defined(ASIO_NOEXCEPT)
+
+// Support automatic type deduction on compilers known to support it.
+#if !defined(ASIO_HAS_DECLTYPE)
+# if !defined(ASIO_DISABLE_DECLTYPE)
+#  if defined(__clang__)
+#   if __has_feature(__cxx_decltype__)
+#    define ASIO_HAS_DECLTYPE 1
+#   endif // __has_feature(__cxx_decltype__)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_DECLTYPE 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_DECLTYPE 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_DECLTYPE)
+#endif // !defined(ASIO_HAS_DECLTYPE)
+
+// Support alias templates on compilers known to allow it.
+#if !defined(ASIO_HAS_ALIAS_TEMPLATES)
+# if !defined(ASIO_DISABLE_ALIAS_TEMPLATES)
+#  if defined(__clang__)
+#   if __has_feature(__cxx_alias_templates__)
+#    define ASIO_HAS_ALIAS_TEMPLATES 1
+#   endif // __has_feature(__cxx_alias_templates__)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_ALIAS_TEMPLATES 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1900)
+#    define ASIO_HAS_ALIAS_TEMPLATES 1
+#   endif // (_MSC_VER >= 1900)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_ALIAS_TEMPLATES)
+#endif // !defined(ASIO_HAS_ALIAS_TEMPLATES)
+
+// Standard library support for system errors.
+#if !defined(ASIO_HAS_STD_SYSTEM_ERROR)
+# if !defined(ASIO_DISABLE_STD_SYSTEM_ERROR)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_SYSTEM_ERROR 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<system_error>)
+#     define ASIO_HAS_STD_SYSTEM_ERROR 1
+#    endif // __has_include(<system_error>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_SYSTEM_ERROR 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_SYSTEM_ERROR 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_SYSTEM_ERROR)
+#endif // !defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+// Compliant C++11 compilers put noexcept specifiers on error_category members.
+#if !defined(ASIO_ERROR_CATEGORY_NOEXCEPT)
+# if (BOOST_VERSION >= 105300)
+#  define ASIO_ERROR_CATEGORY_NOEXCEPT BOOST_NOEXCEPT
+# elif defined(__clang__)
+#  if __has_feature(__cxx_noexcept__)
+#   define ASIO_ERROR_CATEGORY_NOEXCEPT noexcept(true)
+#  endif // __has_feature(__cxx_noexcept__)
+# elif defined(__GNUC__)
+#  if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#   if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_ERROR_CATEGORY_NOEXCEPT noexcept(true)
+#   endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+# elif defined(ASIO_MSVC)
+#  if (_MSC_VER >= 1900)
+#   define ASIO_ERROR_CATEGORY_NOEXCEPT noexcept(true)
+#  endif // (_MSC_VER >= 1900)
+# endif // defined(ASIO_MSVC)
+# if !defined(ASIO_ERROR_CATEGORY_NOEXCEPT)
+#  define ASIO_ERROR_CATEGORY_NOEXCEPT
+# endif // !defined(ASIO_ERROR_CATEGORY_NOEXCEPT)
+#endif // !defined(ASIO_ERROR_CATEGORY_NOEXCEPT)
+
+// Standard library support for arrays.
+#if !defined(ASIO_HAS_STD_ARRAY)
+# if !defined(ASIO_DISABLE_STD_ARRAY)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_ARRAY 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<array>)
+#     define ASIO_HAS_STD_ARRAY 1
+#    endif // __has_include(<array>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_ARRAY 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1600)
+#    define ASIO_HAS_STD_ARRAY 1
+#   endif // (_MSC_VER >= 1600)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_ARRAY)
+#endif // !defined(ASIO_HAS_STD_ARRAY)
+
+// Standard library support for shared_ptr and weak_ptr.
+#if !defined(ASIO_HAS_STD_SHARED_PTR)
+# if !defined(ASIO_DISABLE_STD_SHARED_PTR)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_SHARED_PTR 1
+#   elif (__cplusplus >= 201103)
+#    define ASIO_HAS_STD_SHARED_PTR 1
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_SHARED_PTR 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1600)
+#    define ASIO_HAS_STD_SHARED_PTR 1
+#   endif // (_MSC_VER >= 1600)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_SHARED_PTR)
+#endif // !defined(ASIO_HAS_STD_SHARED_PTR)
+
+// Standard library support for allocator_arg_t.
+#if !defined(ASIO_HAS_STD_ALLOCATOR_ARG)
+# if !defined(ASIO_DISABLE_STD_ALLOCATOR_ARG)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_ALLOCATOR_ARG 1
+#   elif (__cplusplus >= 201103)
+#    define ASIO_HAS_STD_ALLOCATOR_ARG 1
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_ALLOCATOR_ARG 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1600)
+#    define ASIO_HAS_STD_ALLOCATOR_ARG 1
+#   endif // (_MSC_VER >= 1600)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_ALLOCATOR_ARG)
+#endif // !defined(ASIO_HAS_STD_ALLOCATOR_ARG)
+
+// Standard library support for atomic operations.
+#if !defined(ASIO_HAS_STD_ATOMIC)
+# if !defined(ASIO_DISABLE_STD_ATOMIC)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_ATOMIC 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<atomic>)
+#     define ASIO_HAS_STD_ATOMIC 1
+#    endif // __has_include(<atomic>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_ATOMIC 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_ATOMIC 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_ATOMIC)
+#endif // !defined(ASIO_HAS_STD_ATOMIC)
+
+// Standard library support for chrono. Some standard libraries (such as the
+// libstdc++ shipped with gcc 4.6) provide monotonic_clock as per early C++0x
+// drafts, rather than the eventually standardised name of steady_clock.
+#if !defined(ASIO_HAS_STD_CHRONO)
+# if !defined(ASIO_DISABLE_STD_CHRONO)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_CHRONO 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<chrono>)
+#     define ASIO_HAS_STD_CHRONO 1
+#    endif // __has_include(<chrono>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_CHRONO 1
+#     if ((__GNUC__ == 4) && (__GNUC_MINOR__ == 6))
+#      define ASIO_HAS_STD_CHRONO_MONOTONIC_CLOCK 1
+#     endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ == 6))
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_CHRONO 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_CHRONO)
+#endif // !defined(ASIO_HAS_STD_CHRONO)
+
+// Boost support for chrono.
+#if !defined(ASIO_HAS_BOOST_CHRONO)
+# if !defined(ASIO_DISABLE_BOOST_CHRONO)
+#  if (BOOST_VERSION >= 104700)
+#   define ASIO_HAS_BOOST_CHRONO 1
+#  endif // (BOOST_VERSION >= 104700)
+# endif // !defined(ASIO_DISABLE_BOOST_CHRONO)
+#endif // !defined(ASIO_HAS_BOOST_CHRONO)
+
+// Some form of chrono library is available.
+#if !defined(ASIO_HAS_CHRONO)
+# if defined(ASIO_HAS_STD_CHRONO) \
+    || defined(ASIO_HAS_BOOST_CHRONO)
+#  define ASIO_HAS_CHRONO 1
+# endif // defined(ASIO_HAS_STD_CHRONO)
+        // || defined(ASIO_HAS_BOOST_CHRONO)
+#endif // !defined(ASIO_HAS_CHRONO)
+
+// Boost support for the DateTime library.
+#if !defined(ASIO_HAS_BOOST_DATE_TIME)
+# if !defined(ASIO_DISABLE_BOOST_DATE_TIME)
+#  define ASIO_HAS_BOOST_DATE_TIME 1
+# endif // !defined(ASIO_DISABLE_BOOST_DATE_TIME)
+#endif // !defined(ASIO_HAS_BOOST_DATE_TIME)
+
+// Standard library support for addressof.
+#if !defined(ASIO_HAS_STD_ADDRESSOF)
+# if !defined(ASIO_DISABLE_STD_ADDRESSOF)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_ADDRESSOF 1
+#   elif (__cplusplus >= 201103)
+#    define ASIO_HAS_STD_ADDRESSOF 1
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_ADDRESSOF 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_ADDRESSOF 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_ADDRESSOF)
+#endif // !defined(ASIO_HAS_STD_ADDRESSOF)
+
+// Standard library support for the function class.
+#if !defined(ASIO_HAS_STD_FUNCTION)
+# if !defined(ASIO_DISABLE_STD_FUNCTION)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_FUNCTION 1
+#   elif (__cplusplus >= 201103)
+#    define ASIO_HAS_STD_FUNCTION 1
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_FUNCTION 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_FUNCTION 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_FUNCTION)
+#endif // !defined(ASIO_HAS_STD_FUNCTION)
+
+// Standard library support for type traits.
+#if !defined(ASIO_HAS_STD_TYPE_TRAITS)
+# if !defined(ASIO_DISABLE_STD_TYPE_TRAITS)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_TYPE_TRAITS 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<type_traits>)
+#     define ASIO_HAS_STD_TYPE_TRAITS 1
+#    endif // __has_include(<type_traits>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_TYPE_TRAITS 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_TYPE_TRAITS 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_TYPE_TRAITS)
+#endif // !defined(ASIO_HAS_STD_TYPE_TRAITS)
+
+// Standard library support for the nullptr_t type.
+#if !defined(ASIO_HAS_NULLPTR)
+# if !defined(ASIO_DISABLE_NULLPTR)
+#  if defined(__clang__)
+#   if __has_feature(__cxx_nullptr__)
+#    define ASIO_HAS_NULLPTR 1
+#   endif // __has_feature(__cxx_rvalue_references__)
+#  elif defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_NULLPTR 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 6)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_NULLPTR 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_NULLPTR)
+#endif // !defined(ASIO_HAS_NULLPTR)
+
+// Standard library support for the C++11 allocator additions.
+#if !defined(ASIO_HAS_CXX11_ALLOCATORS)
+# if !defined(ASIO_DISABLE_CXX11_ALLOCATORS)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_CXX11_ALLOCATORS 1
+#   elif (__cplusplus >= 201103)
+#    define ASIO_HAS_CXX11_ALLOCATORS 1
+#   endif // (__cplusplus >= 201103)
+#  elif defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_CXX11_ALLOCATORS 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1800)
+#    define ASIO_HAS_CXX11_ALLOCATORS 1
+#   endif // (_MSC_VER >= 1800)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_CXX11_ALLOCATORS)
+#endif // !defined(ASIO_HAS_CXX11_ALLOCATORS)
+
+// Standard library support for the cstdint header.
+#if !defined(ASIO_HAS_CSTDINT)
+# if !defined(ASIO_DISABLE_CSTDINT)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_CSTDINT 1
+#   elif (__cplusplus >= 201103)
+#    define ASIO_HAS_CSTDINT 1
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_CSTDINT 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_CSTDINT 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_CSTDINT)
+#endif // !defined(ASIO_HAS_CSTDINT)
+
+// Standard library support for the thread class.
+#if !defined(ASIO_HAS_STD_THREAD)
+# if !defined(ASIO_DISABLE_STD_THREAD)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_THREAD 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<thread>)
+#     define ASIO_HAS_STD_THREAD 1
+#    endif // __has_include(<thread>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_THREAD 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_THREAD 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_THREAD)
+#endif // !defined(ASIO_HAS_STD_THREAD)
+
+// Standard library support for the mutex and condition variable classes.
+#if !defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+# if !defined(ASIO_DISABLE_STD_MUTEX_AND_CONDVAR)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_MUTEX_AND_CONDVAR 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<mutex>)
+#     define ASIO_HAS_STD_MUTEX_AND_CONDVAR 1
+#    endif // __has_include(<mutex>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_MUTEX_AND_CONDVAR 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_MUTEX_AND_CONDVAR 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_MUTEX_AND_CONDVAR)
+#endif // !defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+
+// Standard library support for the call_once function.
+#if !defined(ASIO_HAS_STD_CALL_ONCE)
+# if !defined(ASIO_DISABLE_STD_CALL_ONCE)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_CALL_ONCE 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<mutex>)
+#     define ASIO_HAS_STD_CALL_ONCE 1
+#    endif // __has_include(<mutex>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_CALL_ONCE 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_CALL_ONCE 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_CALL_ONCE)
+#endif // !defined(ASIO_HAS_STD_CALL_ONCE)
+
+// Standard library support for futures.
+#if !defined(ASIO_HAS_STD_FUTURE)
+# if !defined(ASIO_DISABLE_STD_FUTURE)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    define ASIO_HAS_STD_FUTURE 1
+#   elif (__cplusplus >= 201103)
+#    if __has_include(<future>)
+#     define ASIO_HAS_STD_FUTURE 1
+#    endif // __has_include(<mutex>)
+#   endif // (__cplusplus >= 201103)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_FUTURE 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_FUTURE 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_FUTURE)
+#endif // !defined(ASIO_HAS_STD_FUTURE)
+
+// Standard library support for std::string_view.
+#if !defined(ASIO_HAS_STD_STRING_VIEW)
+# if !defined(ASIO_DISABLE_STD_STRING_VIEW)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    if (__cplusplus >= 201402)
+#     if __has_include(<string_view>)
+#      define ASIO_HAS_STD_STRING_VIEW 1
+#     endif // __has_include(<string_view>)
+#    endif // (__cplusplus >= 201402)
+#   else // defined(ASIO_HAS_CLANG_LIBCXX)
+#    if (__cplusplus >= 201703)
+#     if __has_include(<string_view>)
+#      define ASIO_HAS_STD_STRING_VIEW 1
+#     endif // __has_include(<string_view>)
+#    endif // (__cplusplus >= 201703)
+#   endif // defined(ASIO_HAS_CLANG_LIBCXX)
+#  elif defined(__GNUC__)
+#   if (__GNUC__ >= 7)
+#    if (__cplusplus >= 201703)
+#     define ASIO_HAS_STD_STRING_VIEW 1
+#    endif // (__cplusplus >= 201703)
+#   endif // (__GNUC__ >= 7)
+#  elif defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1910 && _MSVC_LANG >= 201703)
+#    define ASIO_HAS_STD_STRING_VIEW 1
+#   endif // (_MSC_VER >= 1910 && _MSVC_LANG >= 201703)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_STRING_VIEW)
+#endif // !defined(ASIO_HAS_STD_STRING_VIEW)
+
+// Standard library support for std::experimental::string_view.
+#if !defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+# if !defined(ASIO_DISABLE_STD_EXPERIMENTAL_STRING_VIEW)
+#  if defined(__clang__)
+#   if defined(ASIO_HAS_CLANG_LIBCXX)
+#    if (_LIBCPP_VERSION < 7000)
+#     if (__cplusplus >= 201402)
+#      if __has_include(<experimental/string_view>)
+#       define ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW 1
+#      endif // __has_include(<experimental/string_view>)
+#     endif // (__cplusplus >= 201402)
+#    endif // (_LIBCPP_VERSION < 7000)
+#   else // defined(ASIO_HAS_CLANG_LIBCXX)
+#    if (__cplusplus >= 201402)
+#     if __has_include(<experimental/string_view>)
+#      define ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW 1
+#     endif // __has_include(<experimental/string_view>)
+#    endif // (__cplusplus >= 201402)
+#   endif // // defined(ASIO_HAS_CLANG_LIBCXX)
+#  endif // defined(__clang__)
+#  if defined(__GNUC__)
+#   if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 9)) || (__GNUC__ > 4)
+#    if (__cplusplus >= 201402)
+#     define ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW 1
+#    endif // (__cplusplus >= 201402)
+#   endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 9)) || (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+# endif // !defined(ASIO_DISABLE_STD_EXPERIMENTAL_STRING_VIEW)
+#endif // !defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+
+// Standard library has a string_view that we can use.
+#if !defined(ASIO_HAS_STRING_VIEW)
+# if !defined(ASIO_DISABLE_STRING_VIEW)
+#  if defined(ASIO_HAS_STD_STRING_VIEW)
+#   define ASIO_HAS_STRING_VIEW 1
+#  elif defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+#   define ASIO_HAS_STRING_VIEW 1
+#  endif // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+# endif // !defined(ASIO_DISABLE_STRING_VIEW)
+#endif // !defined(ASIO_HAS_STRING_VIEW)
+
+// Standard library support for iostream move construction and assignment.
+#if !defined(ASIO_HAS_STD_IOSTREAM_MOVE)
+# if !defined(ASIO_DISABLE_STD_IOSTREAM_MOVE)
+#  if defined(__GNUC__)
+#   if (__GNUC__ > 4)
+#    if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#     define ASIO_HAS_STD_IOSTREAM_MOVE 1
+#    endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#   endif // (__GNUC__ > 4)
+#  endif // defined(__GNUC__)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1700)
+#    define ASIO_HAS_STD_IOSTREAM_MOVE 1
+#   endif // (_MSC_VER >= 1700)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_IOSTREAM_MOVE)
+#endif // !defined(ASIO_HAS_STD_IOSTREAM_MOVE)
+
+// Standard library has invoke_result (which supersedes result_of).
+#if !defined(ASIO_HAS_STD_INVOKE_RESULT)
+# if !defined(ASIO_DISABLE_STD_INVOKE_RESULT)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_VER >= 1911 && _MSVC_LANG >= 201703)
+#    define ASIO_HAS_STD_INVOKE_RESULT 1
+#   endif // (_MSC_VER >= 1911 && _MSVC_LANG >= 201703)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_STD_INVOKE_RESULT)
+#endif // !defined(ASIO_HAS_STD_INVOKE_RESULT)
+
+// Windows App target. Windows but with a limited API.
+#if !defined(ASIO_WINDOWS_APP)
+# if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0603)
+#  include <winapifamily.h>
+#  if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP) \
+   && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#   define ASIO_WINDOWS_APP 1
+#  endif // WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP)
+         // && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+# endif // defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0603)
+#endif // !defined(ASIO_WINDOWS_APP)
+
+// Legacy WinRT target. Windows App is preferred.
+#if !defined(ASIO_WINDOWS_RUNTIME)
+# if !defined(ASIO_WINDOWS_APP)
+#  if defined(__cplusplus_winrt)
+#   include <winapifamily.h>
+#   if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP) \
+    && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#    define ASIO_WINDOWS_RUNTIME 1
+#   endif // WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP)
+          // && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#  endif // defined(__cplusplus_winrt)
+# endif // !defined(ASIO_WINDOWS_APP)
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+// Windows target. Excludes WinRT but includes Windows App targets.
+#if !defined(ASIO_WINDOWS)
+# if !defined(ASIO_WINDOWS_RUNTIME)
+#  if defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_WINDOWS)
+#   define ASIO_WINDOWS 1
+#  elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
+#   define ASIO_WINDOWS 1
+#  elif defined(ASIO_WINDOWS_APP)
+#   define ASIO_WINDOWS 1
+#  endif // defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_WINDOWS)
+# endif // !defined(ASIO_WINDOWS_RUNTIME)
+#endif // !defined(ASIO_WINDOWS)
+
+// Windows: target OS version.
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if !defined(_WIN32_WINNT) && !defined(_WIN32_WINDOWS)
+#  if defined(_MSC_VER) || defined(__BORLANDC__)
+#   pragma message( \
+  "Please define _WIN32_WINNT or _WIN32_WINDOWS appropriately. For example:\n"\
+  "- add -D_WIN32_WINNT=0x0501 to the compiler command line; or\n"\
+  "- add _WIN32_WINNT=0x0501 to your project's Preprocessor Definitions.\n"\
+  "Assuming _WIN32_WINNT=0x0501 (i.e. Windows XP target).")
+#  else // defined(_MSC_VER) || defined(__BORLANDC__)
+#   warning Please define _WIN32_WINNT or _WIN32_WINDOWS appropriately.
+#   warning For example, add -D_WIN32_WINNT=0x0501 to the compiler command line.
+#   warning Assuming _WIN32_WINNT=0x0501 (i.e. Windows XP target).
+#  endif // defined(_MSC_VER) || defined(__BORLANDC__)
+#  define _WIN32_WINNT 0x0501
+# endif // !defined(_WIN32_WINNT) && !defined(_WIN32_WINDOWS)
+# if defined(_MSC_VER)
+#  if defined(_WIN32) && !defined(WIN32)
+#   if !defined(_WINSOCK2API_)
+#    define WIN32 // Needed for correct types in winsock2.h
+#   else // !defined(_WINSOCK2API_)
+#    error Please define the macro WIN32 in your compiler options
+#   endif // !defined(_WINSOCK2API_)
+#  endif // defined(_WIN32) && !defined(WIN32)
+# endif // defined(_MSC_VER)
+# if defined(__BORLANDC__)
+#  if defined(__WIN32__) && !defined(WIN32)
+#   if !defined(_WINSOCK2API_)
+#    define WIN32 // Needed for correct types in winsock2.h
+#   else // !defined(_WINSOCK2API_)
+#    error Please define the macro WIN32 in your compiler options
+#   endif // !defined(_WINSOCK2API_)
+#  endif // defined(__WIN32__) && !defined(WIN32)
+# endif // defined(__BORLANDC__)
+# if defined(__CYGWIN__)
+#  if !defined(__USE_W32_SOCKETS)
+#   error You must add -D__USE_W32_SOCKETS to your compiler options.
+#  endif // !defined(__USE_W32_SOCKETS)
+# endif // defined(__CYGWIN__)
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+// Windows: minimise header inclusion.
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if !defined(ASIO_NO_WIN32_LEAN_AND_MEAN)
+#  if !defined(WIN32_LEAN_AND_MEAN)
+#   define WIN32_LEAN_AND_MEAN
+#  endif // !defined(WIN32_LEAN_AND_MEAN)
+# endif // !defined(ASIO_NO_WIN32_LEAN_AND_MEAN)
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+// Windows: suppress definition of "min" and "max" macros.
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if !defined(ASIO_NO_NOMINMAX)
+#  if !defined(NOMINMAX)
+#   define NOMINMAX 1
+#  endif // !defined(NOMINMAX)
+# endif // !defined(ASIO_NO_NOMINMAX)
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+// Windows: IO Completion Ports.
+#if !defined(ASIO_HAS_IOCP)
+# if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+#  if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0400)
+#   if !defined(UNDER_CE) && !defined(ASIO_WINDOWS_APP)
+#    if !defined(ASIO_DISABLE_IOCP)
+#     define ASIO_HAS_IOCP 1
+#    endif // !defined(ASIO_DISABLE_IOCP)
+#   endif // !defined(UNDER_CE) && !defined(ASIO_WINDOWS_APP)
+#  endif // defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0400)
+# endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+#endif // !defined(ASIO_HAS_IOCP)
+
+// On POSIX (and POSIX-like) platforms we need to include unistd.h in order to
+// get access to the various platform feature macros, e.g. to be able to test
+// for threads support.
+#if !defined(ASIO_HAS_UNISTD_H)
+# if !defined(ASIO_HAS_BOOST_CONFIG)
+#  if defined(unix) \
+   || defined(__unix) \
+   || defined(_XOPEN_SOURCE) \
+   || defined(_POSIX_SOURCE) \
+   || (defined(__MACH__) && defined(__APPLE__)) \
+   || defined(__FreeBSD__) \
+   || defined(__NetBSD__) \
+   || defined(__OpenBSD__) \
+   || defined(__linux__)
+#   define ASIO_HAS_UNISTD_H 1
+#  endif
+# endif // !defined(ASIO_HAS_BOOST_CONFIG)
+#endif // !defined(ASIO_HAS_UNISTD_H)
+#if defined(ASIO_HAS_UNISTD_H)
+# include <unistd.h>
+#endif // defined(ASIO_HAS_UNISTD_H)
+
+// Linux: epoll, eventfd and timerfd.
+#if defined(__linux__)
+# include <linux/version.h>
+# if !defined(ASIO_HAS_EPOLL)
+#  if !defined(ASIO_DISABLE_EPOLL)
+#   if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,45)
+#    define ASIO_HAS_EPOLL 1
+#   endif // LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,45)
+#  endif // !defined(ASIO_DISABLE_EPOLL)
+# endif // !defined(ASIO_HAS_EPOLL)
+# if !defined(ASIO_HAS_EVENTFD)
+#  if !defined(ASIO_DISABLE_EVENTFD)
+#   if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
+#    define ASIO_HAS_EVENTFD 1
+#   endif // LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
+#  endif // !defined(ASIO_DISABLE_EVENTFD)
+# endif // !defined(ASIO_HAS_EVENTFD)
+# if !defined(ASIO_HAS_TIMERFD)
+#  if defined(ASIO_HAS_EPOLL)
+#   if (__GLIBC__ > 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 8)
+#    define ASIO_HAS_TIMERFD 1
+#   endif // (__GLIBC__ > 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 8)
+#  endif // defined(ASIO_HAS_EPOLL)
+# endif // !defined(ASIO_HAS_TIMERFD)
+#endif // defined(__linux__)
+
+// Mac OS X, FreeBSD, NetBSD, OpenBSD: kqueue.
+#if (defined(__MACH__) && defined(__APPLE__)) \
+  || defined(__FreeBSD__) \
+  || defined(__NetBSD__) \
+  || defined(__OpenBSD__)
+# if !defined(ASIO_HAS_KQUEUE)
+#  if !defined(ASIO_DISABLE_KQUEUE)
+#   define ASIO_HAS_KQUEUE 1
+#  endif // !defined(ASIO_DISABLE_KQUEUE)
+# endif // !defined(ASIO_HAS_KQUEUE)
+#endif // (defined(__MACH__) && defined(__APPLE__))
+       //   || defined(__FreeBSD__)
+       //   || defined(__NetBSD__)
+       //   || defined(__OpenBSD__)
+
+// Solaris: /dev/poll.
+#if defined(__sun)
+# if !defined(ASIO_HAS_DEV_POLL)
+#  if !defined(ASIO_DISABLE_DEV_POLL)
+#   define ASIO_HAS_DEV_POLL 1
+#  endif // !defined(ASIO_DISABLE_DEV_POLL)
+# endif // !defined(ASIO_HAS_DEV_POLL)
+#endif // defined(__sun)
+
+// Serial ports.
+#if !defined(ASIO_HAS_SERIAL_PORT)
+# if defined(ASIO_HAS_IOCP) \
+  || !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+#  if !defined(__SYMBIAN32__)
+#   if !defined(ASIO_DISABLE_SERIAL_PORT)
+#    define ASIO_HAS_SERIAL_PORT 1
+#   endif // !defined(ASIO_DISABLE_SERIAL_PORT)
+#  endif // !defined(__SYMBIAN32__)
+# endif // defined(ASIO_HAS_IOCP)
+        //   || !defined(ASIO_WINDOWS)
+        //   && !defined(ASIO_WINDOWS_RUNTIME)
+        //   && !defined(__CYGWIN__)
+#endif // !defined(ASIO_HAS_SERIAL_PORT)
+
+// Windows: stream handles.
+#if !defined(ASIO_HAS_WINDOWS_STREAM_HANDLE)
+# if !defined(ASIO_DISABLE_WINDOWS_STREAM_HANDLE)
+#  if defined(ASIO_HAS_IOCP)
+#   define ASIO_HAS_WINDOWS_STREAM_HANDLE 1
+#  endif // defined(ASIO_HAS_IOCP)
+# endif // !defined(ASIO_DISABLE_WINDOWS_STREAM_HANDLE)
+#endif // !defined(ASIO_HAS_WINDOWS_STREAM_HANDLE)
+
+// Windows: random access handles.
+#if !defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
+# if !defined(ASIO_DISABLE_WINDOWS_RANDOM_ACCESS_HANDLE)
+#  if defined(ASIO_HAS_IOCP)
+#   define ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE 1
+#  endif // defined(ASIO_HAS_IOCP)
+# endif // !defined(ASIO_DISABLE_WINDOWS_RANDOM_ACCESS_HANDLE)
+#endif // !defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
+
+// Windows: object handles.
+#if !defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+# if !defined(ASIO_DISABLE_WINDOWS_OBJECT_HANDLE)
+#  if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+#   if !defined(UNDER_CE) && !defined(ASIO_WINDOWS_APP)
+#    define ASIO_HAS_WINDOWS_OBJECT_HANDLE 1
+#   endif // !defined(UNDER_CE) && !defined(ASIO_WINDOWS_APP)
+#  endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# endif // !defined(ASIO_DISABLE_WINDOWS_OBJECT_HANDLE)
+#endif // !defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+
+// Windows: OVERLAPPED wrapper.
+#if !defined(ASIO_HAS_WINDOWS_OVERLAPPED_PTR)
+# if !defined(ASIO_DISABLE_WINDOWS_OVERLAPPED_PTR)
+#  if defined(ASIO_HAS_IOCP)
+#   define ASIO_HAS_WINDOWS_OVERLAPPED_PTR 1
+#  endif // defined(ASIO_HAS_IOCP)
+# endif // !defined(ASIO_DISABLE_WINDOWS_OVERLAPPED_PTR)
+#endif // !defined(ASIO_HAS_WINDOWS_OVERLAPPED_PTR)
+
+// POSIX: stream-oriented file descriptors.
+#if !defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+# if !defined(ASIO_DISABLE_POSIX_STREAM_DESCRIPTOR)
+#  if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+#   define ASIO_HAS_POSIX_STREAM_DESCRIPTOR 1
+#  endif // !defined(ASIO_WINDOWS)
+         //   && !defined(ASIO_WINDOWS_RUNTIME)
+         //   && !defined(__CYGWIN__)
+# endif // !defined(ASIO_DISABLE_POSIX_STREAM_DESCRIPTOR)
+#endif // !defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+
+// UNIX domain sockets.
+#if !defined(ASIO_HAS_LOCAL_SOCKETS)
+# if !defined(ASIO_DISABLE_LOCAL_SOCKETS)
+#  if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+#   define ASIO_HAS_LOCAL_SOCKETS 1
+#  endif // !defined(ASIO_WINDOWS)
+         //   && !defined(ASIO_WINDOWS_RUNTIME)
+         //   && !defined(__CYGWIN__)
+# endif // !defined(ASIO_DISABLE_LOCAL_SOCKETS)
+#endif // !defined(ASIO_HAS_LOCAL_SOCKETS)
+
+// Can use sigaction() instead of signal().
+#if !defined(ASIO_HAS_SIGACTION)
+# if !defined(ASIO_DISABLE_SIGACTION)
+#  if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+#   define ASIO_HAS_SIGACTION 1
+#  endif // !defined(ASIO_WINDOWS)
+         //   && !defined(ASIO_WINDOWS_RUNTIME)
+         //   && !defined(__CYGWIN__)
+# endif // !defined(ASIO_DISABLE_SIGACTION)
+#endif // !defined(ASIO_HAS_SIGACTION)
+
+// Can use signal().
+#if !defined(ASIO_HAS_SIGNAL)
+# if !defined(ASIO_DISABLE_SIGNAL)
+#  if !defined(UNDER_CE)
+#   define ASIO_HAS_SIGNAL 1
+#  endif // !defined(UNDER_CE)
+# endif // !defined(ASIO_DISABLE_SIGNAL)
+#endif // !defined(ASIO_HAS_SIGNAL)
+
+// Can use getaddrinfo() and getnameinfo().
+#if !defined(ASIO_HAS_GETADDRINFO)
+# if !defined(ASIO_DISABLE_GETADDRINFO)
+#  if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+#   if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0501)
+#    define ASIO_HAS_GETADDRINFO 1
+#   elif defined(UNDER_CE)
+#    define ASIO_HAS_GETADDRINFO 1
+#   endif // defined(UNDER_CE)
+#  elif defined(__MACH__) && defined(__APPLE__)
+#   if defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
+#    if (__MAC_OS_X_VERSION_MIN_REQUIRED >= 1050)
+#     define ASIO_HAS_GETADDRINFO 1
+#    endif // (__MAC_OS_X_VERSION_MIN_REQUIRED >= 1050)
+#   else // defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
+#    define ASIO_HAS_GETADDRINFO 1
+#   endif // defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
+#  else // defined(__MACH__) && defined(__APPLE__)
+#   define ASIO_HAS_GETADDRINFO 1
+#  endif // defined(__MACH__) && defined(__APPLE__)
+# endif // !defined(ASIO_DISABLE_GETADDRINFO)
+#endif // !defined(ASIO_HAS_GETADDRINFO)
+
+// Whether standard iostreams are disabled.
+#if !defined(ASIO_NO_IOSTREAM)
+# if defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_NO_IOSTREAM)
+#  define ASIO_NO_IOSTREAM 1
+# endif // !defined(BOOST_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+// Whether exception handling is disabled.
+#if !defined(ASIO_NO_EXCEPTIONS)
+# if defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_NO_EXCEPTIONS)
+#  define ASIO_NO_EXCEPTIONS 1
+# endif // !defined(BOOST_NO_EXCEPTIONS)
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+
+// Whether the typeid operator is supported.
+#if !defined(ASIO_NO_TYPEID)
+# if defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_NO_TYPEID)
+#  define ASIO_NO_TYPEID 1
+# endif // !defined(BOOST_NO_TYPEID)
+#endif // !defined(ASIO_NO_TYPEID)
+
+// Threads.
+#if !defined(ASIO_HAS_THREADS)
+# if !defined(ASIO_DISABLE_THREADS)
+#  if defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_HAS_THREADS)
+#   define ASIO_HAS_THREADS 1
+#  elif defined(__GNUC__) && !defined(__MINGW32__) \
+     && !defined(linux) && !defined(__linux) && !defined(__linux__)
+#   define ASIO_HAS_THREADS 1
+#  elif defined(_MT) || defined(__MT__)
+#   define ASIO_HAS_THREADS 1
+#  elif defined(_REENTRANT)
+#   define ASIO_HAS_THREADS 1
+#  elif defined(__APPLE__)
+#   define ASIO_HAS_THREADS 1
+#  elif defined(_POSIX_THREADS) && (_POSIX_THREADS + 0 >= 0)
+#   define ASIO_HAS_THREADS 1
+#  elif defined(_PTHREADS)
+#   define ASIO_HAS_THREADS 1
+#  endif // defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_HAS_THREADS)
+# endif // !defined(ASIO_DISABLE_THREADS)
+#endif // !defined(ASIO_HAS_THREADS)
+
+// POSIX threads.
+#if !defined(ASIO_HAS_PTHREADS)
+# if defined(ASIO_HAS_THREADS)
+#  if defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_HAS_PTHREADS)
+#   define ASIO_HAS_PTHREADS 1
+#  elif defined(_POSIX_THREADS) && (_POSIX_THREADS + 0 >= 0)
+#   define ASIO_HAS_PTHREADS 1
+#  endif // defined(ASIO_HAS_BOOST_CONFIG) && defined(BOOST_HAS_PTHREADS)
+# endif // defined(ASIO_HAS_THREADS)
+#endif // !defined(ASIO_HAS_PTHREADS)
+
+// Helper to prevent macro expansion.
+#define ASIO_PREVENT_MACRO_SUBSTITUTION
+
+// Helper to define in-class constants.
+#if !defined(ASIO_STATIC_CONSTANT)
+# if !defined(ASIO_DISABLE_BOOST_STATIC_CONSTANT)
+#  define ASIO_STATIC_CONSTANT(type, assignment) \
+    BOOST_STATIC_CONSTANT(type, assignment)
+# else // !defined(ASIO_DISABLE_BOOST_STATIC_CONSTANT)
+#  define ASIO_STATIC_CONSTANT(type, assignment) \
+    static const type assignment
+# endif // !defined(ASIO_DISABLE_BOOST_STATIC_CONSTANT)
+#endif // !defined(ASIO_STATIC_CONSTANT)
+
+// Boost array library.
+#if !defined(ASIO_HAS_BOOST_ARRAY)
+# if !defined(ASIO_DISABLE_BOOST_ARRAY)
+#  define ASIO_HAS_BOOST_ARRAY 1
+# endif // !defined(ASIO_DISABLE_BOOST_ARRAY)
+#endif // !defined(ASIO_HAS_BOOST_ARRAY)
+
+// Boost assert macro.
+#if !defined(ASIO_HAS_BOOST_ASSERT)
+# if !defined(ASIO_DISABLE_BOOST_ASSERT)
+#  define ASIO_HAS_BOOST_ASSERT 1
+# endif // !defined(ASIO_DISABLE_BOOST_ASSERT)
+#endif // !defined(ASIO_HAS_BOOST_ASSERT)
+
+// Boost limits header.
+#if !defined(ASIO_HAS_BOOST_LIMITS)
+# if !defined(ASIO_DISABLE_BOOST_LIMITS)
+#  define ASIO_HAS_BOOST_LIMITS 1
+# endif // !defined(ASIO_DISABLE_BOOST_LIMITS)
+#endif // !defined(ASIO_HAS_BOOST_LIMITS)
+
+// Boost throw_exception function.
+#if !defined(ASIO_HAS_BOOST_THROW_EXCEPTION)
+# if !defined(ASIO_DISABLE_BOOST_THROW_EXCEPTION)
+#  define ASIO_HAS_BOOST_THROW_EXCEPTION 1
+# endif // !defined(ASIO_DISABLE_BOOST_THROW_EXCEPTION)
+#endif // !defined(ASIO_HAS_BOOST_THROW_EXCEPTION)
+
+// Boost regex library.
+#if !defined(ASIO_HAS_BOOST_REGEX)
+# if !defined(ASIO_DISABLE_BOOST_REGEX)
+#  define ASIO_HAS_BOOST_REGEX 1
+# endif // !defined(ASIO_DISABLE_BOOST_REGEX)
+#endif // !defined(ASIO_HAS_BOOST_REGEX)
+
+// Boost bind function.
+#if !defined(ASIO_HAS_BOOST_BIND)
+# if !defined(ASIO_DISABLE_BOOST_BIND)
+#  define ASIO_HAS_BOOST_BIND 1
+# endif // !defined(ASIO_DISABLE_BOOST_BIND)
+#endif // !defined(ASIO_HAS_BOOST_BIND)
+
+// Boost's BOOST_WORKAROUND macro.
+#if !defined(ASIO_HAS_BOOST_WORKAROUND)
+# if !defined(ASIO_DISABLE_BOOST_WORKAROUND)
+#  define ASIO_HAS_BOOST_WORKAROUND 1
+# endif // !defined(ASIO_DISABLE_BOOST_WORKAROUND)
+#endif // !defined(ASIO_HAS_BOOST_WORKAROUND)
+
+// Microsoft Visual C++'s secure C runtime library.
+#if !defined(ASIO_HAS_SECURE_RTL)
+# if !defined(ASIO_DISABLE_SECURE_RTL)
+#  if defined(ASIO_MSVC) \
+    && (ASIO_MSVC >= 1400) \
+    && !defined(UNDER_CE)
+#   define ASIO_HAS_SECURE_RTL 1
+#  endif // defined(ASIO_MSVC)
+         // && (ASIO_MSVC >= 1400)
+         // && !defined(UNDER_CE)
+# endif // !defined(ASIO_DISABLE_SECURE_RTL)
+#endif // !defined(ASIO_HAS_SECURE_RTL)
+
+// Handler hooking. Disabled for ancient Borland C++ and gcc compilers.
+#if !defined(ASIO_HAS_HANDLER_HOOKS)
+# if !defined(ASIO_DISABLE_HANDLER_HOOKS)
+#  if defined(__GNUC__)
+#   if (__GNUC__ >= 3)
+#    define ASIO_HAS_HANDLER_HOOKS 1
+#   endif // (__GNUC__ >= 3)
+#  elif !defined(__BORLANDC__)
+#   define ASIO_HAS_HANDLER_HOOKS 1
+#  endif // !defined(__BORLANDC__)
+# endif // !defined(ASIO_DISABLE_HANDLER_HOOKS)
+#endif // !defined(ASIO_HAS_HANDLER_HOOKS)
+
+// Support for the __thread keyword extension.
+#if !defined(ASIO_DISABLE_THREAD_KEYWORD_EXTENSION)
+# if defined(__linux__)
+#  if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+#   if ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3)
+#    if !defined(__INTEL_COMPILER) && !defined(__ICL) \
+       && !(defined(__clang__) && defined(__ANDROID__))
+#     define ASIO_HAS_THREAD_KEYWORD_EXTENSION 1
+#     define ASIO_THREAD_KEYWORD __thread
+#    elif defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 1100)
+#     define ASIO_HAS_THREAD_KEYWORD_EXTENSION 1
+#    endif // defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 1100)
+           // && !(defined(__clang__) && defined(__ANDROID__))
+#   endif // ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3)
+#  endif // defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+# endif // defined(__linux__)
+# if defined(ASIO_MSVC) && defined(ASIO_WINDOWS_RUNTIME)
+#  if (_MSC_VER >= 1700)
+#   define ASIO_HAS_THREAD_KEYWORD_EXTENSION 1
+#   define ASIO_THREAD_KEYWORD __declspec(thread)
+#  endif // (_MSC_VER >= 1700)
+# endif // defined(ASIO_MSVC) && defined(ASIO_WINDOWS_RUNTIME)
+#endif // !defined(ASIO_DISABLE_THREAD_KEYWORD_EXTENSION)
+#if !defined(ASIO_THREAD_KEYWORD)
+# define ASIO_THREAD_KEYWORD __thread
+#endif // !defined(ASIO_THREAD_KEYWORD)
+
+// Support for POSIX ssize_t typedef.
+#if !defined(ASIO_DISABLE_SSIZE_T)
+# if defined(__linux__) \
+   || (defined(__MACH__) && defined(__APPLE__))
+#  define ASIO_HAS_SSIZE_T 1
+# endif // defined(__linux__)
+        //   || (defined(__MACH__) && defined(__APPLE__))
+#endif // !defined(ASIO_DISABLE_SSIZE_T)
+
+// Helper macros to manage the transition away from the old services-based API.
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# define ASIO_SVC_TPARAM , typename Service
+# define ASIO_SVC_TPARAM_DEF1(d1) , typename Service d1
+# define ASIO_SVC_TPARAM_DEF2(d1, d2) , typename Service d1, d2
+# define ASIO_SVC_TARG , Service
+# define ASIO_SVC_T Service
+# define ASIO_SVC_TPARAM1 , typename Service1
+# define ASIO_SVC_TPARAM1_DEF1(d1) , typename Service1 d1
+# define ASIO_SVC_TPARAM1_DEF2(d1, d2) , typename Service1 d1, d2
+# define ASIO_SVC_TARG1 , Service1
+# define ASIO_SVC_T1 Service1
+# define ASIO_SVC_ACCESS public
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+# define ASIO_SVC_TPARAM
+# define ASIO_SVC_TPARAM_DEF1(d1)
+# define ASIO_SVC_TPARAM_DEF2(d1, d2)
+# define ASIO_SVC_TARG
+// ASIO_SVC_T is defined at each point of use.
+# define ASIO_SVC_TPARAM1
+# define ASIO_SVC_TPARAM1_DEF1(d1)
+# define ASIO_SVC_TPARAM1_DEF2(d1, d2)
+# define ASIO_SVC_TARG1
+// ASIO_SVC_T1 is defined at each point of use.
+# define ASIO_SVC_ACCESS protected
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+// Helper macros to manage transition away from error_code return values.
+#if defined(ASIO_NO_DEPRECATED)
+# define ASIO_SYNC_OP_VOID void
+# define ASIO_SYNC_OP_VOID_RETURN(e) return
+#else // defined(ASIO_NO_DEPRECATED)
+# define ASIO_SYNC_OP_VOID asio::error_code
+# define ASIO_SYNC_OP_VOID_RETURN(e) return e
+#endif // defined(ASIO_NO_DEPRECATED)
+
+// Newer gcc, clang need special treatment to suppress unused typedef warnings.
+#if defined(__clang__)
+# if defined(__apple_build_version__)
+#  if (__clang_major__ >= 7)
+#   define ASIO_UNUSED_TYPEDEF __attribute__((__unused__))
+#  endif // (__clang_major__ >= 7)
+# elif ((__clang_major__ == 3) && (__clang_minor__ >= 6)) \
+    || (__clang_major__ > 3)
+#  define ASIO_UNUSED_TYPEDEF __attribute__((__unused__))
+# endif // ((__clang_major__ == 3) && (__clang_minor__ >= 6))
+        //   || (__clang_major__ > 3)
+#elif defined(__GNUC__)
+# if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 8)) || (__GNUC__ > 4)
+#  define ASIO_UNUSED_TYPEDEF __attribute__((__unused__))
+# endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 8)) || (__GNUC__ > 4)
+#endif // defined(__GNUC__)
+#if !defined(ASIO_UNUSED_TYPEDEF)
+# define ASIO_UNUSED_TYPEDEF
+#endif // !defined(ASIO_UNUSED_TYPEDEF)
+
+// Some versions of gcc generate spurious warnings about unused variables.
+#if defined(__GNUC__)
+# if (__GNUC__ >= 4)
+#  define ASIO_UNUSED_VARIABLE __attribute__((__unused__))
+# endif // (__GNUC__ >= 4)
+#endif // defined(__GNUC__)
+#if !defined(ASIO_UNUSED_VARIABLE)
+# define ASIO_UNUSED_VARIABLE
+#endif // !defined(ASIO_UNUSED_VARIABLE)
+
+// Support co_await on compilers known to allow it.
+#if !defined(ASIO_HAS_CO_AWAIT)
+# if !defined(ASIO_DISABLE_CO_AWAIT)
+#  if defined(ASIO_MSVC)
+#   if (_MSC_FULL_VER >= 190023506)
+#    if defined(_RESUMABLE_FUNCTIONS_SUPPORTED)
+#     define ASIO_HAS_CO_AWAIT 1
+#    endif // defined(_RESUMABLE_FUNCTIONS_SUPPORTED)
+#   endif // (_MSC_FULL_VER >= 190023506)
+#  endif // defined(ASIO_MSVC)
+# endif // !defined(ASIO_DISABLE_CO_AWAIT)
+# if defined(__clang__)
+#  if (__cpp_coroutines >= 201703)
+#   if __has_include(<experimental/coroutine>)
+#    define ASIO_HAS_CO_AWAIT 1
+#   endif // __has_include(<experimental/coroutine>)
+#  endif // (__cpp_coroutines >= 201703)
+# endif // defined(__clang__)
+#endif // !defined(ASIO_HAS_CO_AWAIT)
+
+#endif // ASIO_DETAIL_CONFIG_HPP
diff --git a/subprojects/asio/include/asio/detail/consuming_buffers.hpp b/subprojects/asio/include/asio/detail/consuming_buffers.hpp
new file mode 100644
index 000000000..8127ae75c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/consuming_buffers.hpp
@@ -0,0 +1,414 @@
+//
+// detail/consuming_buffers.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CONSUMING_BUFFERS_HPP
+#define ASIO_DETAIL_CONSUMING_BUFFERS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/buffer.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/limits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper template to determine the maximum number of prepared buffers.
+template <typename Buffers>
+struct prepared_buffers_max
+{
+  enum { value = buffer_sequence_adapter_base::max_buffers };
+};
+
+template <typename Elem, std::size_t N>
+struct prepared_buffers_max<boost::array<Elem, N> >
+{
+  enum { value = N };
+};
+
+#if defined(ASIO_HAS_STD_ARRAY)
+
+template <typename Elem, std::size_t N>
+struct prepared_buffers_max<std::array<Elem, N> >
+{
+  enum { value = N };
+};
+
+#endif // defined(ASIO_HAS_STD_ARRAY)
+
+// A buffer sequence used to represent a subsequence of the buffers.
+template <typename Buffer, std::size_t MaxBuffers>
+struct prepared_buffers
+{
+  typedef Buffer value_type;
+  typedef const Buffer* const_iterator;
+
+  enum { max_buffers = MaxBuffers < 16 ? MaxBuffers : 16 };
+
+  prepared_buffers() : count(0) {}
+  const_iterator begin() const { return elems; }
+  const_iterator end() const { return elems + count; }
+
+  Buffer elems[max_buffers];
+  std::size_t count;
+};
+
+// A proxy for a sub-range in a list of buffers.
+template <typename Buffer, typename Buffers, typename Buffer_Iterator>
+class consuming_buffers
+{
+public:
+  typedef prepared_buffers<Buffer, prepared_buffers_max<Buffers>::value>
+    prepared_buffers_type;
+
+  // Construct to represent the entire list of buffers.
+  explicit consuming_buffers(const Buffers& buffers)
+    : buffers_(buffers),
+      total_consumed_(0),
+      next_elem_(0),
+      next_elem_offset_(0)
+  {
+    using asio::buffer_size;
+    total_size_ = buffer_size(buffers);
+  }
+
+  // Determine if we are at the end of the buffers.
+  bool empty() const
+  {
+    return total_consumed_ >= total_size_;
+  }
+
+  // Get the buffer for a single transfer, with a size.
+  prepared_buffers_type prepare(std::size_t max_size)
+  {
+    prepared_buffers_type result;
+
+    Buffer_Iterator next = asio::buffer_sequence_begin(buffers_);
+    Buffer_Iterator end = asio::buffer_sequence_end(buffers_);
+
+    std::advance(next, next_elem_);
+    std::size_t elem_offset = next_elem_offset_;
+    while (next != end && max_size > 0 && (result.count) < result.max_buffers)
+    {
+      Buffer next_buf = Buffer(*next) + elem_offset;
+      result.elems[result.count] = asio::buffer(next_buf, max_size);
+      max_size -= result.elems[result.count].size();
+      elem_offset = 0;
+      if (result.elems[result.count].size() > 0)
+        ++result.count;
+      ++next;
+    }
+
+    return result;
+  }
+
+  // Consume the specified number of bytes from the buffers.
+  void consume(std::size_t size)
+  {
+    total_consumed_ += size;
+
+    Buffer_Iterator next = asio::buffer_sequence_begin(buffers_);
+    Buffer_Iterator end = asio::buffer_sequence_end(buffers_);
+
+    std::advance(next, next_elem_);
+    while (next != end && size > 0)
+    {
+      Buffer next_buf = Buffer(*next) + next_elem_offset_;
+      if (size < next_buf.size())
+      {
+        next_elem_offset_ += size;
+        size = 0;
+      }
+      else
+      {
+        size -= next_buf.size();
+        next_elem_offset_ = 0;
+        ++next_elem_;
+        ++next;
+      }
+    }
+  }
+
+  // Get the total number of bytes consumed from the buffers.
+  std::size_t total_consumed() const
+  {
+    return total_consumed_;
+  }
+
+private:
+  Buffers buffers_;
+  std::size_t total_size_;
+  std::size_t total_consumed_;
+  std::size_t next_elem_;
+  std::size_t next_elem_offset_;
+};
+
+// Base class of all consuming_buffers specialisations for single buffers.
+template <typename Buffer>
+class consuming_single_buffer
+{
+public:
+  // Construct to represent the entire list of buffers.
+  template <typename Buffer1>
+  explicit consuming_single_buffer(const Buffer1& buffer)
+    : buffer_(buffer),
+      total_consumed_(0)
+  {
+  }
+
+  // Determine if we are at the end of the buffers.
+  bool empty() const
+  {
+    return total_consumed_ >= buffer_.size();
+  }
+
+  // Get the buffer for a single transfer, with a size.
+  Buffer prepare(std::size_t max_size)
+  {
+    return asio::buffer(buffer_ + total_consumed_, max_size);
+  }
+
+  // Consume the specified number of bytes from the buffers.
+  void consume(std::size_t size)
+  {
+    total_consumed_ += size;
+  }
+
+  // Get the total number of bytes consumed from the buffers.
+  std::size_t total_consumed() const
+  {
+    return total_consumed_;
+  }
+
+private:
+  Buffer buffer_;
+  std::size_t total_consumed_;
+};
+
+template <>
+class consuming_buffers<mutable_buffer, mutable_buffer, const mutable_buffer*>
+  : public consuming_single_buffer<ASIO_MUTABLE_BUFFER>
+{
+public:
+  explicit consuming_buffers(const mutable_buffer& buffer)
+    : consuming_single_buffer<ASIO_MUTABLE_BUFFER>(buffer)
+  {
+  }
+};
+
+template <>
+class consuming_buffers<const_buffer, mutable_buffer, const mutable_buffer*>
+  : public consuming_single_buffer<ASIO_CONST_BUFFER>
+{
+public:
+  explicit consuming_buffers(const mutable_buffer& buffer)
+    : consuming_single_buffer<ASIO_CONST_BUFFER>(buffer)
+  {
+  }
+};
+
+template <>
+class consuming_buffers<const_buffer, const_buffer, const const_buffer*>
+  : public consuming_single_buffer<ASIO_CONST_BUFFER>
+{
+public:
+  explicit consuming_buffers(const const_buffer& buffer)
+    : consuming_single_buffer<ASIO_CONST_BUFFER>(buffer)
+  {
+  }
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+template <>
+class consuming_buffers<mutable_buffer,
+    mutable_buffers_1, const mutable_buffer*>
+  : public consuming_single_buffer<ASIO_MUTABLE_BUFFER>
+{
+public:
+  explicit consuming_buffers(const mutable_buffers_1& buffer)
+    : consuming_single_buffer<ASIO_MUTABLE_BUFFER>(buffer)
+  {
+  }
+};
+
+template <>
+class consuming_buffers<const_buffer, mutable_buffers_1, const mutable_buffer*>
+  : public consuming_single_buffer<ASIO_CONST_BUFFER>
+{
+public:
+  explicit consuming_buffers(const mutable_buffers_1& buffer)
+    : consuming_single_buffer<ASIO_CONST_BUFFER>(buffer)
+  {
+  }
+};
+
+template <>
+class consuming_buffers<const_buffer, const_buffers_1, const const_buffer*>
+  : public consuming_single_buffer<ASIO_CONST_BUFFER>
+{
+public:
+  explicit consuming_buffers(const const_buffers_1& buffer)
+    : consuming_single_buffer<ASIO_CONST_BUFFER>(buffer)
+  {
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Buffer, typename Elem>
+class consuming_buffers<Buffer, boost::array<Elem, 2>,
+    typename boost::array<Elem, 2>::const_iterator>
+{
+public:
+  // Construct to represent the entire list of buffers.
+  explicit consuming_buffers(const boost::array<Elem, 2>& buffers)
+    : buffers_(buffers),
+      total_consumed_(0)
+  {
+  }
+
+  // Determine if we are at the end of the buffers.
+  bool empty() const
+  {
+    return total_consumed_ >=
+      Buffer(buffers_[0]).size() + Buffer(buffers_[1]).size();
+  }
+
+  // Get the buffer for a single transfer, with a size.
+  boost::array<Buffer, 2> prepare(std::size_t max_size)
+  {
+    boost::array<Buffer, 2> result = {{
+      Buffer(buffers_[0]), Buffer(buffers_[1]) }};
+    std::size_t buffer0_size = result[0].size();
+    result[0] = asio::buffer(result[0] + total_consumed_, max_size);
+    result[1] = asio::buffer(
+        result[1] + (total_consumed_ < buffer0_size
+          ? 0 : total_consumed_ - buffer0_size),
+        max_size - result[0].size());
+    return result;
+  }
+
+  // Consume the specified number of bytes from the buffers.
+  void consume(std::size_t size)
+  {
+    total_consumed_ += size;
+  }
+
+  // Get the total number of bytes consumed from the buffers.
+  std::size_t total_consumed() const
+  {
+    return total_consumed_;
+  }
+
+private:
+  boost::array<Elem, 2> buffers_;
+  std::size_t total_consumed_;
+};
+
+#if defined(ASIO_HAS_STD_ARRAY)
+
+template <typename Buffer, typename Elem>
+class consuming_buffers<Buffer, std::array<Elem, 2>,
+    typename std::array<Elem, 2>::const_iterator>
+{
+public:
+  // Construct to represent the entire list of buffers.
+  explicit consuming_buffers(const std::array<Elem, 2>& buffers)
+    : buffers_(buffers),
+      total_consumed_(0)
+  {
+  }
+
+  // Determine if we are at the end of the buffers.
+  bool empty() const
+  {
+    return total_consumed_ >=
+      Buffer(buffers_[0]).size() + Buffer(buffers_[1]).size();
+  }
+
+  // Get the buffer for a single transfer, with a size.
+  std::array<Buffer, 2> prepare(std::size_t max_size)
+  {
+    std::array<Buffer, 2> result = {{
+      Buffer(buffers_[0]), Buffer(buffers_[1]) }};
+    std::size_t buffer0_size = result[0].size();
+    result[0] = asio::buffer(result[0] + total_consumed_, max_size);
+    result[1] = asio::buffer(
+        result[1] + (total_consumed_ < buffer0_size
+          ? 0 : total_consumed_ - buffer0_size),
+        max_size - result[0].size());
+    return result;
+  }
+
+  // Consume the specified number of bytes from the buffers.
+  void consume(std::size_t size)
+  {
+    total_consumed_ += size;
+  }
+
+  // Get the total number of bytes consumed from the buffers.
+  std::size_t total_consumed() const
+  {
+    return total_consumed_;
+  }
+
+private:
+  std::array<Elem, 2> buffers_;
+  std::size_t total_consumed_;
+};
+
+#endif // defined(ASIO_HAS_STD_ARRAY)
+
+// Specialisation for null_buffers to ensure that the null_buffers type is
+// always passed through to the underlying read or write operation.
+template <typename Buffer>
+class consuming_buffers<Buffer, null_buffers, const mutable_buffer*>
+  : public asio::null_buffers
+{
+public:
+  consuming_buffers(const null_buffers&)
+  {
+    // No-op.
+  }
+
+  bool empty()
+  {
+    return false;
+  }
+
+  null_buffers prepare(std::size_t)
+  {
+    return null_buffers();
+  }
+
+  void consume(std::size_t)
+  {
+    // No-op.
+  }
+
+  std::size_t total_consumed() const
+  {
+    return 0;
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_CONSUMING_BUFFERS_HPP
diff --git a/subprojects/asio/include/asio/detail/cstddef.hpp b/subprojects/asio/include/asio/detail/cstddef.hpp
new file mode 100644
index 000000000..3912da40d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/cstddef.hpp
@@ -0,0 +1,31 @@
+//
+// detail/cstddef.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CSTDDEF_HPP
+#define ASIO_DETAIL_CSTDDEF_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+
+namespace asio {
+
+#if defined(ASIO_HAS_NULLPTR)
+using std::nullptr_t;
+#else // defined(ASIO_HAS_NULLPTR)
+struct nullptr_t {};
+#endif // defined(ASIO_HAS_NULLPTR)
+
+} // namespace asio
+
+#endif // ASIO_DETAIL_CSTDDEF_HPP
diff --git a/subprojects/asio/include/asio/detail/cstdint.hpp b/subprojects/asio/include/asio/detail/cstdint.hpp
new file mode 100644
index 000000000..62342b2d2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/cstdint.hpp
@@ -0,0 +1,60 @@
+//
+// detail/cstdint.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_CSTDINT_HPP
+#define ASIO_DETAIL_CSTDINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_CSTDINT)
+# include <cstdint>
+#else // defined(ASIO_HAS_CSTDINT)
+# include <boost/cstdint.hpp>
+#endif // defined(ASIO_HAS_CSTDINT)
+
+namespace asio {
+
+#if defined(ASIO_HAS_CSTDINT)
+using std::int16_t;
+using std::int_least16_t;
+using std::uint16_t;
+using std::uint_least16_t;
+using std::int32_t;
+using std::int_least32_t;
+using std::uint32_t;
+using std::uint_least32_t;
+using std::int64_t;
+using std::int_least64_t;
+using std::uint64_t;
+using std::uint_least64_t;
+using std::uintmax_t;
+#else // defined(ASIO_HAS_CSTDINT)
+using boost::int16_t;
+using boost::int_least16_t;
+using boost::uint16_t;
+using boost::uint_least16_t;
+using boost::int32_t;
+using boost::int_least32_t;
+using boost::uint32_t;
+using boost::uint_least32_t;
+using boost::int64_t;
+using boost::int_least64_t;
+using boost::uint64_t;
+using boost::uint_least64_t;
+using boost::uintmax_t;
+#endif // defined(ASIO_HAS_CSTDINT)
+
+} // namespace asio
+
+#endif // ASIO_DETAIL_CSTDINT_HPP
diff --git a/subprojects/asio/include/asio/detail/date_time_fwd.hpp b/subprojects/asio/include/asio/detail/date_time_fwd.hpp
new file mode 100644
index 000000000..a159562eb
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/date_time_fwd.hpp
@@ -0,0 +1,34 @@
+//
+// detail/date_time_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DATE_TIME_FWD_HPP
+#define ASIO_DETAIL_DATE_TIME_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+namespace boost {
+namespace date_time {
+
+template<class T, class TimeSystem>
+class base_time;
+
+} // namespace date_time
+namespace posix_time {
+
+class ptime;
+
+} // namespace posix_time
+} // namespace boost
+
+#endif // ASIO_DETAIL_DATE_TIME_FWD_HPP
diff --git a/subprojects/asio/include/asio/detail/deadline_timer_service.hpp b/subprojects/asio/include/asio/detail/deadline_timer_service.hpp
new file mode 100644
index 000000000..f58a6e0e7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/deadline_timer_service.hpp
@@ -0,0 +1,278 @@
+//
+// detail/deadline_timer_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DEADLINE_TIMER_SERVICE_HPP
+#define ASIO_DETAIL_DEADLINE_TIMER_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/timer_queue.hpp"
+#include "asio/detail/timer_queue_ptime.hpp"
+#include "asio/detail/timer_scheduler.hpp"
+#include "asio/detail/wait_handler.hpp"
+#include "asio/detail/wait_op.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include <chrono>
+# include <thread>
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+class deadline_timer_service
+  : public service_base<deadline_timer_service<Time_Traits> >
+{
+public:
+  // The time type.
+  typedef typename Time_Traits::time_type time_type;
+
+  // The duration type.
+  typedef typename Time_Traits::duration_type duration_type;
+
+  // The implementation type of the timer. This type is dependent on the
+  // underlying implementation of the timer service.
+  struct implementation_type
+    : private asio::detail::noncopyable
+  {
+    time_type expiry;
+    bool might_have_pending_waits;
+    typename timer_queue<Time_Traits>::per_timer_data timer_data;
+  };
+
+  // Constructor.
+  deadline_timer_service(asio::io_context& io_context)
+    : service_base<deadline_timer_service<Time_Traits> >(io_context),
+      scheduler_(asio::use_service<timer_scheduler>(io_context))
+  {
+    scheduler_.init_task();
+    scheduler_.add_timer_queue(timer_queue_);
+  }
+
+  // Destructor.
+  ~deadline_timer_service()
+  {
+    scheduler_.remove_timer_queue(timer_queue_);
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+  }
+
+  // Construct a new timer implementation.
+  void construct(implementation_type& impl)
+  {
+    impl.expiry = time_type();
+    impl.might_have_pending_waits = false;
+  }
+
+  // Destroy a timer implementation.
+  void destroy(implementation_type& impl)
+  {
+    asio::error_code ec;
+    cancel(impl, ec);
+  }
+
+  // Move-construct a new serial port implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    scheduler_.move_timer(timer_queue_, impl.timer_data, other_impl.timer_data);
+
+    impl.expiry = other_impl.expiry;
+    other_impl.expiry = time_type();
+
+    impl.might_have_pending_waits = other_impl.might_have_pending_waits;
+    other_impl.might_have_pending_waits = false;
+  }
+
+  // Move-assign from another serial port implementation.
+  void move_assign(implementation_type& impl,
+      deadline_timer_service& other_service,
+      implementation_type& other_impl)
+  {
+    if (this != &other_service)
+      if (impl.might_have_pending_waits)
+        scheduler_.cancel_timer(timer_queue_, impl.timer_data);
+
+    other_service.scheduler_.move_timer(other_service.timer_queue_,
+        impl.timer_data, other_impl.timer_data);
+
+    impl.expiry = other_impl.expiry;
+    other_impl.expiry = time_type();
+
+    impl.might_have_pending_waits = other_impl.might_have_pending_waits;
+    other_impl.might_have_pending_waits = false;
+  }
+
+  // Cancel any asynchronous wait operations associated with the timer.
+  std::size_t cancel(implementation_type& impl, asio::error_code& ec)
+  {
+    if (!impl.might_have_pending_waits)
+    {
+      ec = asio::error_code();
+      return 0;
+    }
+
+    ASIO_HANDLER_OPERATION((scheduler_.context(),
+          "deadline_timer", &impl, 0, "cancel"));
+
+    std::size_t count = scheduler_.cancel_timer(timer_queue_, impl.timer_data);
+    impl.might_have_pending_waits = false;
+    ec = asio::error_code();
+    return count;
+  }
+
+  // Cancels one asynchronous wait operation associated with the timer.
+  std::size_t cancel_one(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    if (!impl.might_have_pending_waits)
+    {
+      ec = asio::error_code();
+      return 0;
+    }
+
+    ASIO_HANDLER_OPERATION((scheduler_.context(),
+          "deadline_timer", &impl, 0, "cancel_one"));
+
+    std::size_t count = scheduler_.cancel_timer(
+        timer_queue_, impl.timer_data, 1);
+    if (count == 0)
+      impl.might_have_pending_waits = false;
+    ec = asio::error_code();
+    return count;
+  }
+
+  // Get the expiry time for the timer as an absolute time.
+  time_type expiry(const implementation_type& impl) const
+  {
+    return impl.expiry;
+  }
+
+  // Get the expiry time for the timer as an absolute time.
+  time_type expires_at(const implementation_type& impl) const
+  {
+    return impl.expiry;
+  }
+
+  // Get the expiry time for the timer relative to now.
+  duration_type expires_from_now(const implementation_type& impl) const
+  {
+    return Time_Traits::subtract(this->expiry(impl), Time_Traits::now());
+  }
+
+  // Set the expiry time for the timer as an absolute time.
+  std::size_t expires_at(implementation_type& impl,
+      const time_type& expiry_time, asio::error_code& ec)
+  {
+    std::size_t count = cancel(impl, ec);
+    impl.expiry = expiry_time;
+    ec = asio::error_code();
+    return count;
+  }
+
+  // Set the expiry time for the timer relative to now.
+  std::size_t expires_after(implementation_type& impl,
+      const duration_type& expiry_time, asio::error_code& ec)
+  {
+    return expires_at(impl,
+        Time_Traits::add(Time_Traits::now(), expiry_time), ec);
+  }
+
+  // Set the expiry time for the timer relative to now.
+  std::size_t expires_from_now(implementation_type& impl,
+      const duration_type& expiry_time, asio::error_code& ec)
+  {
+    return expires_at(impl,
+        Time_Traits::add(Time_Traits::now(), expiry_time), ec);
+  }
+
+  // Perform a blocking wait on the timer.
+  void wait(implementation_type& impl, asio::error_code& ec)
+  {
+    time_type now = Time_Traits::now();
+    ec = asio::error_code();
+    while (Time_Traits::less_than(now, impl.expiry) && !ec)
+    {
+      this->do_wait(Time_Traits::to_posix_duration(
+            Time_Traits::subtract(impl.expiry, now)), ec);
+      now = Time_Traits::now();
+    }
+  }
+
+  // Start an asynchronous wait on the timer.
+  template <typename Handler>
+  void async_wait(implementation_type& impl, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef wait_handler<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    impl.might_have_pending_waits = true;
+
+    ASIO_HANDLER_CREATION((scheduler_.context(),
+          *p.p, "deadline_timer", &impl, 0, "async_wait"));
+
+    scheduler_.schedule_timer(timer_queue_, impl.expiry, impl.timer_data, p.p);
+    p.v = p.p = 0;
+  }
+
+private:
+  // Helper function to wait given a duration type. The duration type should
+  // either be of type boost::posix_time::time_duration, or implement the
+  // required subset of its interface.
+  template <typename Duration>
+  void do_wait(const Duration& timeout, asio::error_code& ec)
+  {
+#if defined(ASIO_WINDOWS_RUNTIME)
+    std::this_thread::sleep_for(
+        std::chrono::seconds(timeout.total_seconds())
+        + std::chrono::microseconds(timeout.total_microseconds()));
+    ec = asio::error_code();
+#else // defined(ASIO_WINDOWS_RUNTIME)
+    ::timeval tv;
+    tv.tv_sec = timeout.total_seconds();
+    tv.tv_usec = timeout.total_microseconds() % 1000000;
+    socket_ops::select(0, 0, 0, 0, &tv, ec);
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+  }
+
+  // The queue of timers.
+  timer_queue<Time_Traits> timer_queue_;
+
+  // The object that schedules and executes timers. Usually a reactor.
+  timer_scheduler& scheduler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_DEADLINE_TIMER_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/dependent_type.hpp b/subprojects/asio/include/asio/detail/dependent_type.hpp
new file mode 100644
index 000000000..85b41c893
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/dependent_type.hpp
@@ -0,0 +1,36 @@
+//
+// detail/dependent_type.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DEPENDENT_TYPE_HPP
+#define ASIO_DETAIL_DEPENDENT_TYPE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename DependsOn, typename T>
+struct dependent_type
+{
+  typedef T type;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_DEPENDENT_TYPE_HPP
diff --git a/subprojects/asio/include/asio/detail/descriptor_ops.hpp b/subprojects/asio/include/asio/detail/descriptor_ops.hpp
new file mode 100644
index 000000000..9c0560aa2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/descriptor_ops.hpp
@@ -0,0 +1,121 @@
+//
+// detail/descriptor_ops.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DESCRIPTOR_OPS_HPP
+#define ASIO_DETAIL_DESCRIPTOR_OPS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+
+#include <cstddef>
+#include "asio/error.hpp"
+#include "asio/error_code.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace descriptor_ops {
+
+// Descriptor state bits.
+enum
+{
+  // The user wants a non-blocking descriptor.
+  user_set_non_blocking = 1,
+
+  // The descriptor has been set non-blocking.
+  internal_non_blocking = 2,
+
+  // Helper "state" used to determine whether the descriptor is non-blocking.
+  non_blocking = user_set_non_blocking | internal_non_blocking,
+
+  // The descriptor may have been dup()-ed.
+  possible_dup = 4
+};
+
+typedef unsigned char state_type;
+
+template <typename ReturnType>
+inline ReturnType error_wrapper(ReturnType return_value,
+    asio::error_code& ec)
+{
+  ec = asio::error_code(errno,
+      asio::error::get_system_category());
+  return return_value;
+}
+
+ASIO_DECL int open(const char* path, int flags,
+    asio::error_code& ec);
+
+ASIO_DECL int close(int d, state_type& state,
+    asio::error_code& ec);
+
+ASIO_DECL bool set_user_non_blocking(int d,
+    state_type& state, bool value, asio::error_code& ec);
+
+ASIO_DECL bool set_internal_non_blocking(int d,
+    state_type& state, bool value, asio::error_code& ec);
+
+typedef iovec buf;
+
+ASIO_DECL std::size_t sync_read(int d, state_type state, buf* bufs,
+    std::size_t count, bool all_empty, asio::error_code& ec);
+
+ASIO_DECL bool non_blocking_read(int d, buf* bufs, std::size_t count,
+    asio::error_code& ec, std::size_t& bytes_transferred);
+
+ASIO_DECL std::size_t sync_write(int d, state_type state,
+    const buf* bufs, std::size_t count, bool all_empty,
+    asio::error_code& ec);
+
+ASIO_DECL bool non_blocking_write(int d,
+    const buf* bufs, std::size_t count,
+    asio::error_code& ec, std::size_t& bytes_transferred);
+
+ASIO_DECL int ioctl(int d, state_type& state, long cmd,
+    ioctl_arg_type* arg, asio::error_code& ec);
+
+ASIO_DECL int fcntl(int d, int cmd, asio::error_code& ec);
+
+ASIO_DECL int fcntl(int d, int cmd,
+    long arg, asio::error_code& ec);
+
+ASIO_DECL int poll_read(int d,
+    state_type state, asio::error_code& ec);
+
+ASIO_DECL int poll_write(int d,
+    state_type state, asio::error_code& ec);
+
+ASIO_DECL int poll_error(int d,
+    state_type state, asio::error_code& ec);
+
+} // namespace descriptor_ops
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/descriptor_ops.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_DESCRIPTOR_OPS_HPP
diff --git a/subprojects/asio/include/asio/detail/descriptor_read_op.hpp b/subprojects/asio/include/asio/detail/descriptor_read_op.hpp
new file mode 100644
index 000000000..6db4bfb95
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/descriptor_read_op.hpp
@@ -0,0 +1,128 @@
+//
+// detail/descriptor_read_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP
+#define ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/descriptor_ops.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_work.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence>
+class descriptor_read_op_base : public reactor_op
+{
+public:
+  descriptor_read_op_base(int descriptor,
+      const MutableBufferSequence& buffers, func_type complete_func)
+    : reactor_op(&descriptor_read_op_base::do_perform, complete_func),
+      descriptor_(descriptor),
+      buffers_(buffers)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    descriptor_read_op_base* o(static_cast<descriptor_read_op_base*>(base));
+
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(o->buffers_);
+
+    status result = descriptor_ops::non_blocking_read(o->descriptor_,
+        bufs.buffers(), bufs.count(), o->ec_, o->bytes_transferred_)
+      ? done : not_done;
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_read",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  int descriptor_;
+  MutableBufferSequence buffers_;
+};
+
+template <typename MutableBufferSequence, typename Handler>
+class descriptor_read_op
+  : public descriptor_read_op_base<MutableBufferSequence>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(descriptor_read_op);
+
+  descriptor_read_op(int descriptor,
+      const MutableBufferSequence& buffers, Handler& handler)
+    : descriptor_read_op_base<MutableBufferSequence>(
+        descriptor, buffers, &descriptor_read_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    descriptor_read_op* o(static_cast<descriptor_read_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/descriptor_write_op.hpp b/subprojects/asio/include/asio/detail/descriptor_write_op.hpp
new file mode 100644
index 000000000..a9ec2a976
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/descriptor_write_op.hpp
@@ -0,0 +1,128 @@
+//
+// detail/descriptor_write_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DESCRIPTOR_WRITE_OP_HPP
+#define ASIO_DETAIL_DESCRIPTOR_WRITE_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/descriptor_ops.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_work.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename ConstBufferSequence>
+class descriptor_write_op_base : public reactor_op
+{
+public:
+  descriptor_write_op_base(int descriptor,
+      const ConstBufferSequence& buffers, func_type complete_func)
+    : reactor_op(&descriptor_write_op_base::do_perform, complete_func),
+      descriptor_(descriptor),
+      buffers_(buffers)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    descriptor_write_op_base* o(static_cast<descriptor_write_op_base*>(base));
+
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(o->buffers_);
+
+    status result = descriptor_ops::non_blocking_write(o->descriptor_,
+        bufs.buffers(), bufs.count(), o->ec_, o->bytes_transferred_)
+      ? done : not_done;
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_write",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  int descriptor_;
+  ConstBufferSequence buffers_;
+};
+
+template <typename ConstBufferSequence, typename Handler>
+class descriptor_write_op
+  : public descriptor_write_op_base<ConstBufferSequence>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(descriptor_write_op);
+
+  descriptor_write_op(int descriptor,
+      const ConstBufferSequence& buffers, Handler& handler)
+    : descriptor_write_op_base<ConstBufferSequence>(
+        descriptor, buffers, &descriptor_write_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    descriptor_write_op* o(static_cast<descriptor_write_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_DESCRIPTOR_WRITE_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/dev_poll_reactor.hpp b/subprojects/asio/include/asio/detail/dev_poll_reactor.hpp
new file mode 100644
index 000000000..e9e4e29e0
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/dev_poll_reactor.hpp
@@ -0,0 +1,218 @@
+//
+// detail/dev_poll_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_DEV_POLL_REACTOR_HPP
+#define ASIO_DETAIL_DEV_POLL_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_DEV_POLL)
+
+#include <cstddef>
+#include <vector>
+#include <sys/devpoll.h>
+#include "asio/detail/hash_map.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/reactor_op_queue.hpp"
+#include "asio/detail/select_interrupter.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+#include "asio/detail/timer_queue_set.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class dev_poll_reactor
+  : public execution_context_service_base<dev_poll_reactor>
+{
+public:
+  enum op_types { read_op = 0, write_op = 1,
+    connect_op = 1, except_op = 2, max_ops = 3 };
+
+  // Per-descriptor data.
+  struct per_descriptor_data
+  {
+  };
+
+  // Constructor.
+  ASIO_DECL dev_poll_reactor(asio::execution_context& ctx);
+
+  // Destructor.
+  ASIO_DECL ~dev_poll_reactor();
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Recreate internal descriptors following a fork.
+  ASIO_DECL void notify_fork(
+      asio::execution_context::fork_event fork_ev);
+
+  // Initialise the task.
+  ASIO_DECL void init_task();
+
+  // Register a socket with the reactor. Returns 0 on success, system error
+  // code on failure.
+  ASIO_DECL int register_descriptor(socket_type, per_descriptor_data&);
+
+  // Register a descriptor with an associated single operation. Returns 0 on
+  // success, system error code on failure.
+  ASIO_DECL int register_internal_descriptor(
+      int op_type, socket_type descriptor,
+      per_descriptor_data& descriptor_data, reactor_op* op);
+
+  // Move descriptor registration from one descriptor_data object to another.
+  ASIO_DECL void move_descriptor(socket_type descriptor,
+      per_descriptor_data& target_descriptor_data,
+      per_descriptor_data& source_descriptor_data);
+
+  // Post a reactor operation for immediate completion.
+  void post_immediate_completion(reactor_op* op, bool is_continuation)
+  {
+    scheduler_.post_immediate_completion(op, is_continuation);
+  }
+
+  // Start a new operation. The reactor operation will be performed when the
+  // given descriptor is flagged as ready, or an error has occurred.
+  ASIO_DECL void start_op(int op_type, socket_type descriptor,
+      per_descriptor_data&, reactor_op* op,
+      bool is_continuation, bool allow_speculative);
+
+  // Cancel all operations associated with the given descriptor. The
+  // handlers associated with the descriptor will be invoked with the
+  // operation_aborted error.
+  ASIO_DECL void cancel_ops(socket_type descriptor, per_descriptor_data&);
+
+  // Cancel any operations that are running against the descriptor and remove
+  // its registration from the reactor. The reactor resources associated with
+  // the descriptor must be released by calling cleanup_descriptor_data.
+  ASIO_DECL void deregister_descriptor(socket_type descriptor,
+      per_descriptor_data&, bool closing);
+
+  // Remove the descriptor's registration from the reactor. The reactor
+  // resources associated with the descriptor must be released by calling
+  // cleanup_descriptor_data.
+  ASIO_DECL void deregister_internal_descriptor(
+      socket_type descriptor, per_descriptor_data&);
+
+  // Perform any post-deregistration cleanup tasks associated with the
+  // descriptor data.
+  ASIO_DECL void cleanup_descriptor_data(per_descriptor_data&);
+
+  // Add a new timer queue to the reactor.
+  template <typename Time_Traits>
+  void add_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Remove a timer queue from the reactor.
+  template <typename Time_Traits>
+  void remove_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Schedule a new operation in the given timer queue to expire at the
+  // specified absolute time.
+  template <typename Time_Traits>
+  void schedule_timer(timer_queue<Time_Traits>& queue,
+      const typename Time_Traits::time_type& time,
+      typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
+
+  // Cancel the timer operations associated with the given token. Returns the
+  // number of operations that have been posted or dispatched.
+  template <typename Time_Traits>
+  std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& timer,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
+
+  // Move the timer operations associated with the given timer.
+  template <typename Time_Traits>
+  void move_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& target,
+      typename timer_queue<Time_Traits>::per_timer_data& source);
+
+  // Run /dev/poll once until interrupted or events are ready to be dispatched.
+  ASIO_DECL void run(long usec, op_queue<operation>& ops);
+
+  // Interrupt the select loop.
+  ASIO_DECL void interrupt();
+
+private:
+  // Create the /dev/poll file descriptor. Throws an exception if the descriptor
+  // cannot be created.
+  ASIO_DECL static int do_dev_poll_create();
+
+  // Helper function to add a new timer queue.
+  ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
+
+  // Helper function to remove a timer queue.
+  ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
+
+  // Get the timeout value for the /dev/poll DP_POLL operation. The timeout
+  // value is returned as a number of milliseconds. A return value of -1
+  // indicates that the poll should block indefinitely.
+  ASIO_DECL int get_timeout(int msec);
+
+  // Cancel all operations associated with the given descriptor. The do_cancel
+  // function of the handler objects will be invoked. This function does not
+  // acquire the dev_poll_reactor's mutex.
+  ASIO_DECL void cancel_ops_unlocked(socket_type descriptor,
+      const asio::error_code& ec);
+
+  // Add a pending event entry for the given descriptor.
+  ASIO_DECL ::pollfd& add_pending_event_change(int descriptor);
+
+  // The scheduler implementation used to post completions.
+  scheduler& scheduler_;
+
+  // Mutex to protect access to internal data.
+  asio::detail::mutex mutex_;
+
+  // The /dev/poll file descriptor.
+  int dev_poll_fd_;
+
+  // Vector of /dev/poll events waiting to be written to the descriptor.
+  std::vector< ::pollfd> pending_event_changes_;
+
+  // Hash map to associate a descriptor with a pending event change index.
+  hash_map<int, std::size_t> pending_event_change_index_;
+
+  // The interrupter is used to break a blocking DP_POLL operation.
+  select_interrupter interrupter_;
+
+  // The queues of read, write and except operations.
+  reactor_op_queue<socket_type> op_queue_[max_ops];
+
+  // The timer queues.
+  timer_queue_set timer_queues_;
+
+  // Whether the service has been shut down.
+  bool shutdown_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/dev_poll_reactor.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/dev_poll_reactor.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_DEV_POLL)
+
+#endif // ASIO_DETAIL_DEV_POLL_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/epoll_reactor.hpp b/subprojects/asio/include/asio/detail/epoll_reactor.hpp
new file mode 100644
index 000000000..5f5810993
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/epoll_reactor.hpp
@@ -0,0 +1,266 @@
+//
+// detail/epoll_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_EPOLL_REACTOR_HPP
+#define ASIO_DETAIL_EPOLL_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_EPOLL)
+
+#include "asio/detail/atomic_count.hpp"
+#include "asio/detail/conditionally_enabled_mutex.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/object_pool.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/select_interrupter.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+#include "asio/detail/timer_queue_set.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/execution_context.hpp"
+
+#if defined(ASIO_HAS_TIMERFD)
+# include <sys/timerfd.h>
+#endif // defined(ASIO_HAS_TIMERFD)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class epoll_reactor
+  : public execution_context_service_base<epoll_reactor>
+{
+private:
+  // The mutex type used by this reactor.
+  typedef conditionally_enabled_mutex mutex;
+
+public:
+  enum op_types { read_op = 0, write_op = 1,
+    connect_op = 1, except_op = 2, max_ops = 3 };
+
+  // Per-descriptor queues.
+  class descriptor_state : operation
+  {
+    friend class epoll_reactor;
+    friend class object_pool_access;
+
+    descriptor_state* next_;
+    descriptor_state* prev_;
+
+    mutex mutex_;
+    epoll_reactor* reactor_;
+    int descriptor_;
+    uint32_t registered_events_;
+    op_queue<reactor_op> op_queue_[max_ops];
+    bool try_speculative_[max_ops];
+    bool shutdown_;
+
+    ASIO_DECL descriptor_state(bool locking);
+    void set_ready_events(uint32_t events) { task_result_ = events; }
+    void add_ready_events(uint32_t events) { task_result_ |= events; }
+    ASIO_DECL operation* perform_io(uint32_t events);
+    ASIO_DECL static void do_complete(
+        void* owner, operation* base,
+        const asio::error_code& ec, std::size_t bytes_transferred);
+  };
+
+  // Per-descriptor data.
+  typedef descriptor_state* per_descriptor_data;
+
+  // Constructor.
+  ASIO_DECL epoll_reactor(asio::execution_context& ctx);
+
+  // Destructor.
+  ASIO_DECL ~epoll_reactor();
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Recreate internal descriptors following a fork.
+  ASIO_DECL void notify_fork(
+      asio::execution_context::fork_event fork_ev);
+
+  // Initialise the task.
+  ASIO_DECL void init_task();
+
+  // Register a socket with the reactor. Returns 0 on success, system error
+  // code on failure.
+  ASIO_DECL int register_descriptor(socket_type descriptor,
+      per_descriptor_data& descriptor_data);
+
+  // Register a descriptor with an associated single operation. Returns 0 on
+  // success, system error code on failure.
+  ASIO_DECL int register_internal_descriptor(
+      int op_type, socket_type descriptor,
+      per_descriptor_data& descriptor_data, reactor_op* op);
+
+  // Move descriptor registration from one descriptor_data object to another.
+  ASIO_DECL void move_descriptor(socket_type descriptor,
+      per_descriptor_data& target_descriptor_data,
+      per_descriptor_data& source_descriptor_data);
+
+  // Post a reactor operation for immediate completion.
+  void post_immediate_completion(reactor_op* op, bool is_continuation)
+  {
+    scheduler_.post_immediate_completion(op, is_continuation);
+  }
+
+  // Start a new operation. The reactor operation will be performed when the
+  // given descriptor is flagged as ready, or an error has occurred.
+  ASIO_DECL void start_op(int op_type, socket_type descriptor,
+      per_descriptor_data& descriptor_data, reactor_op* op,
+      bool is_continuation, bool allow_speculative);
+
+  // Cancel all operations associated with the given descriptor. The
+  // handlers associated with the descriptor will be invoked with the
+  // operation_aborted error.
+  ASIO_DECL void cancel_ops(socket_type descriptor,
+      per_descriptor_data& descriptor_data);
+
+  // Cancel any operations that are running against the descriptor and remove
+  // its registration from the reactor. The reactor resources associated with
+  // the descriptor must be released by calling cleanup_descriptor_data.
+  ASIO_DECL void deregister_descriptor(socket_type descriptor,
+      per_descriptor_data& descriptor_data, bool closing);
+
+  // Remove the descriptor's registration from the reactor. The reactor
+  // resources associated with the descriptor must be released by calling
+  // cleanup_descriptor_data.
+  ASIO_DECL void deregister_internal_descriptor(
+      socket_type descriptor, per_descriptor_data& descriptor_data);
+
+  // Perform any post-deregistration cleanup tasks associated with the
+  // descriptor data.
+  ASIO_DECL void cleanup_descriptor_data(
+      per_descriptor_data& descriptor_data);
+
+  // Add a new timer queue to the reactor.
+  template <typename Time_Traits>
+  void add_timer_queue(timer_queue<Time_Traits>& timer_queue);
+
+  // Remove a timer queue from the reactor.
+  template <typename Time_Traits>
+  void remove_timer_queue(timer_queue<Time_Traits>& timer_queue);
+
+  // Schedule a new operation in the given timer queue to expire at the
+  // specified absolute time.
+  template <typename Time_Traits>
+  void schedule_timer(timer_queue<Time_Traits>& queue,
+      const typename Time_Traits::time_type& time,
+      typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
+
+  // Cancel the timer operations associated with the given token. Returns the
+  // number of operations that have been posted or dispatched.
+  template <typename Time_Traits>
+  std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& timer,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
+
+  // Move the timer operations associated with the given timer.
+  template <typename Time_Traits>
+  void move_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& target,
+      typename timer_queue<Time_Traits>::per_timer_data& source);
+
+  // Run epoll once until interrupted or events are ready to be dispatched.
+  ASIO_DECL void run(long usec, op_queue<operation>& ops);
+
+  // Interrupt the select loop.
+  ASIO_DECL void interrupt();
+
+private:
+  // The hint to pass to epoll_create to size its data structures.
+  enum { epoll_size = 20000 };
+
+  // Create the epoll file descriptor. Throws an exception if the descriptor
+  // cannot be created.
+  ASIO_DECL static int do_epoll_create();
+
+  // Create the timerfd file descriptor. Does not throw.
+  ASIO_DECL static int do_timerfd_create();
+
+  // Allocate a new descriptor state object.
+  ASIO_DECL descriptor_state* allocate_descriptor_state();
+
+  // Free an existing descriptor state object.
+  ASIO_DECL void free_descriptor_state(descriptor_state* s);
+
+  // Helper function to add a new timer queue.
+  ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
+
+  // Helper function to remove a timer queue.
+  ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
+
+  // Called to recalculate and update the timeout.
+  ASIO_DECL void update_timeout();
+
+  // Get the timeout value for the epoll_wait call. The timeout value is
+  // returned as a number of milliseconds. A return value of -1 indicates
+  // that epoll_wait should block indefinitely.
+  ASIO_DECL int get_timeout(int msec);
+
+#if defined(ASIO_HAS_TIMERFD)
+  // Get the timeout value for the timer descriptor. The return value is the
+  // flag argument to be used when calling timerfd_settime.
+  ASIO_DECL int get_timeout(itimerspec& ts);
+#endif // defined(ASIO_HAS_TIMERFD)
+
+  // The scheduler implementation used to post completions.
+  scheduler& scheduler_;
+
+  // Mutex to protect access to internal data.
+  mutex mutex_;
+
+  // The interrupter is used to break a blocking epoll_wait call.
+  select_interrupter interrupter_;
+
+  // The epoll file descriptor.
+  int epoll_fd_;
+
+  // The timer file descriptor.
+  int timer_fd_;
+
+  // The timer queues.
+  timer_queue_set timer_queues_;
+
+  // Whether the service has been shut down.
+  bool shutdown_;
+
+  // Mutex to protect access to the registered descriptors.
+  mutex registered_descriptors_mutex_;
+
+  // Keep track of all registered descriptors.
+  object_pool<descriptor_state> registered_descriptors_;
+
+  // Helper class to do post-perform_io cleanup.
+  struct perform_io_cleanup_on_block_exit;
+  friend struct perform_io_cleanup_on_block_exit;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/epoll_reactor.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/epoll_reactor.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_EPOLL)
+
+#endif // ASIO_DETAIL_EPOLL_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/event.hpp b/subprojects/asio/include/asio/detail/event.hpp
new file mode 100644
index 000000000..da8fa770b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/event.hpp
@@ -0,0 +1,48 @@
+//
+// detail/event.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_EVENT_HPP
+#define ASIO_DETAIL_EVENT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+# include "asio/detail/null_event.hpp"
+#elif defined(ASIO_WINDOWS)
+# include "asio/detail/win_event.hpp"
+#elif defined(ASIO_HAS_PTHREADS)
+# include "asio/detail/posix_event.hpp"
+#elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+# include "asio/detail/std_event.hpp"
+#else
+# error Only Windows, POSIX and std::condition_variable are supported!
+#endif
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS)
+typedef null_event event;
+#elif defined(ASIO_WINDOWS)
+typedef win_event event;
+#elif defined(ASIO_HAS_PTHREADS)
+typedef posix_event event;
+#elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+typedef std_event event;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_EVENT_HPP
diff --git a/subprojects/asio/include/asio/detail/eventfd_select_interrupter.hpp b/subprojects/asio/include/asio/detail/eventfd_select_interrupter.hpp
new file mode 100644
index 000000000..f6e594b61
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/eventfd_select_interrupter.hpp
@@ -0,0 +1,83 @@
+//
+// detail/eventfd_select_interrupter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Roelof Naude (roelof.naude at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_EVENTFD_SELECT_INTERRUPTER_HPP
+#define ASIO_DETAIL_EVENTFD_SELECT_INTERRUPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_EVENTFD)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class eventfd_select_interrupter
+{
+public:
+  // Constructor.
+  ASIO_DECL eventfd_select_interrupter();
+
+  // Destructor.
+  ASIO_DECL ~eventfd_select_interrupter();
+
+  // Recreate the interrupter's descriptors. Used after a fork.
+  ASIO_DECL void recreate();
+
+  // Interrupt the select call.
+  ASIO_DECL void interrupt();
+
+  // Reset the select interrupt. Returns true if the call was interrupted.
+  ASIO_DECL bool reset();
+
+  // Get the read descriptor to be passed to select.
+  int read_descriptor() const
+  {
+    return read_descriptor_;
+  }
+
+private:
+  // Open the descriptors. Throws on error.
+  ASIO_DECL void open_descriptors();
+
+  // Close the descriptors.
+  ASIO_DECL void close_descriptors();
+
+  // The read end of a connection used to interrupt the select call. This file
+  // descriptor is passed to select such that when it is time to stop, a single
+  // 64bit value will be written on the other end of the connection and this
+  // descriptor will become readable.
+  int read_descriptor_;
+
+  // The write end of a connection used to interrupt the select call. A single
+  // 64bit non-zero value may be written to this to wake up the select which is
+  // waiting for the other end to become readable. This descriptor will only
+  // differ from the read descriptor when a pipe is used.
+  int write_descriptor_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/eventfd_select_interrupter.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_EVENTFD)
+
+#endif // ASIO_DETAIL_EVENTFD_SELECT_INTERRUPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/executor_op.hpp b/subprojects/asio/include/asio/detail/executor_op.hpp
new file mode 100644
index 000000000..2d5c7e8b8
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/executor_op.hpp
@@ -0,0 +1,84 @@
+//
+// detail/executor_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_EXECUTOR_OP_HPP
+#define ASIO_DETAIL_EXECUTOR_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/scheduler_operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler, typename Alloc,
+    typename Operation = scheduler_operation>
+class executor_op : public Operation
+{
+public:
+  ASIO_DEFINE_HANDLER_ALLOCATOR_PTR(executor_op);
+
+  template <typename H>
+  executor_op(ASIO_MOVE_ARG(H) h, const Alloc& allocator)
+    : Operation(&executor_op::do_complete),
+      handler_(ASIO_MOVE_CAST(H)(h)),
+      allocator_(allocator)
+  {
+  }
+
+  static void do_complete(void* owner, Operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    executor_op* o(static_cast<executor_op*>(base));
+    Alloc allocator(o->allocator_);
+    ptr p = { detail::addressof(allocator), o, o };
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    Handler handler(ASIO_MOVE_CAST(Handler)(o->handler_));
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN(());
+      asio_handler_invoke_helpers::invoke(handler, handler);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+  Alloc allocator_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_EXECUTOR_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/fd_set_adapter.hpp b/subprojects/asio/include/asio/detail/fd_set_adapter.hpp
new file mode 100644
index 000000000..fd373dae1
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/fd_set_adapter.hpp
@@ -0,0 +1,39 @@
+//
+// detail/fd_set_adapter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_FD_SET_ADAPTER_HPP
+#define ASIO_DETAIL_FD_SET_ADAPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/posix_fd_set_adapter.hpp"
+#include "asio/detail/win_fd_set_adapter.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+typedef win_fd_set_adapter fd_set_adapter;
+#else
+typedef posix_fd_set_adapter fd_set_adapter;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_FD_SET_ADAPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/fenced_block.hpp b/subprojects/asio/include/asio/detail/fenced_block.hpp
new file mode 100644
index 000000000..dc34bd9fb
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/fenced_block.hpp
@@ -0,0 +1,80 @@
+//
+// detail/fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS) \
+  || defined(ASIO_DISABLE_FENCED_BLOCK)
+# include "asio/detail/null_fenced_block.hpp"
+#elif defined(ASIO_HAS_STD_ATOMIC)
+# include "asio/detail/std_fenced_block.hpp"
+#elif defined(__MACH__) && defined(__APPLE__)
+# include "asio/detail/macos_fenced_block.hpp"
+#elif defined(__sun)
+# include "asio/detail/solaris_fenced_block.hpp"
+#elif defined(__GNUC__) && defined(__arm__) \
+  && !defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
+# include "asio/detail/gcc_arm_fenced_block.hpp"
+#elif defined(__GNUC__) && (defined(__hppa) || defined(__hppa__))
+# include "asio/detail/gcc_hppa_fenced_block.hpp"
+#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+# include "asio/detail/gcc_x86_fenced_block.hpp"
+#elif defined(__GNUC__) \
+  && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)) \
+  && !defined(__INTEL_COMPILER) && !defined(__ICL) \
+  && !defined(__ICC) && !defined(__ECC) && !defined(__PATHSCALE__)
+# include "asio/detail/gcc_sync_fenced_block.hpp"
+#elif defined(ASIO_WINDOWS) && !defined(UNDER_CE)
+# include "asio/detail/win_fenced_block.hpp"
+#else
+# include "asio/detail/null_fenced_block.hpp"
+#endif
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS) \
+  || defined(ASIO_DISABLE_FENCED_BLOCK)
+typedef null_fenced_block fenced_block;
+#elif defined(ASIO_HAS_STD_ATOMIC)
+typedef std_fenced_block fenced_block;
+#elif defined(__MACH__) && defined(__APPLE__)
+typedef macos_fenced_block fenced_block;
+#elif defined(__sun)
+typedef solaris_fenced_block fenced_block;
+#elif defined(__GNUC__) && defined(__arm__) \
+  && !defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
+typedef gcc_arm_fenced_block fenced_block;
+#elif defined(__GNUC__) && (defined(__hppa) || defined(__hppa__))
+typedef gcc_hppa_fenced_block fenced_block;
+#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+typedef gcc_x86_fenced_block fenced_block;
+#elif defined(__GNUC__) \
+  && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)) \
+  && !defined(__INTEL_COMPILER) && !defined(__ICL) \
+  && !defined(__ICC) && !defined(__ECC) && !defined(__PATHSCALE__)
+typedef gcc_sync_fenced_block fenced_block;
+#elif defined(ASIO_WINDOWS) && !defined(UNDER_CE)
+typedef win_fenced_block fenced_block;
+#else
+typedef null_fenced_block fenced_block;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/functional.hpp b/subprojects/asio/include/asio/detail/functional.hpp
new file mode 100644
index 000000000..a37e9e631
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/functional.hpp
@@ -0,0 +1,38 @@
+//
+// detail/functional.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_FUNCTIONAL_HPP
+#define ASIO_DETAIL_FUNCTIONAL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <functional>
+
+#if !defined(ASIO_HAS_STD_FUNCTION)
+# include <boost/function.hpp>
+#endif // !defined(ASIO_HAS_STD_FUNCTION)
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_STD_FUNCTION)
+using std::function;
+#else // defined(ASIO_HAS_STD_FUNCTION)
+using boost::function;
+#endif // defined(ASIO_HAS_STD_FUNCTION)
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_FUNCTIONAL_HPP
diff --git a/subprojects/asio/include/asio/detail/future.hpp b/subprojects/asio/include/asio/detail/future.hpp
new file mode 100644
index 000000000..27461553f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/future.hpp
@@ -0,0 +1,33 @@
+//
+// detail/future.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_FUTURE_HPP
+#define ASIO_DETAIL_FUTURE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#if defined(ASIO_HAS_STD_FUTURE)
+# include <future>
+// Even though the future header is available, libstdc++ may not implement the
+// std::future class itself. However, we need to have already included the
+// future header to reliably test for _GLIBCXX_HAS_GTHREADS.
+# if defined(__GNUC__) && !defined(ASIO_HAS_CLANG_LIBCXX)
+#  if defined(_GLIBCXX_HAS_GTHREADS)
+#   define ASIO_HAS_STD_FUTURE_CLASS 1
+#  endif // defined(_GLIBCXX_HAS_GTHREADS)
+# else // defined(__GNUC__) && !defined(ASIO_HAS_CLANG_LIBCXX)
+#  define ASIO_HAS_STD_FUTURE_CLASS 1
+# endif // defined(__GNUC__) && !defined(ASIO_HAS_CLANG_LIBCXX)
+#endif // defined(ASIO_HAS_STD_FUTURE)
+
+#endif // ASIO_DETAIL_FUTURE_HPP
diff --git a/subprojects/asio/include/asio/detail/gcc_arm_fenced_block.hpp b/subprojects/asio/include/asio/detail/gcc_arm_fenced_block.hpp
new file mode 100644
index 000000000..7919a551c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/gcc_arm_fenced_block.hpp
@@ -0,0 +1,91 @@
+//
+// detail/gcc_arm_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(__GNUC__) && defined(__arm__)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class gcc_arm_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_t { half };
+  enum full_t { full };
+
+  // Constructor for a half fenced block.
+  explicit gcc_arm_fenced_block(half_t)
+  {
+  }
+
+  // Constructor for a full fenced block.
+  explicit gcc_arm_fenced_block(full_t)
+  {
+    barrier();
+  }
+
+  // Destructor.
+  ~gcc_arm_fenced_block()
+  {
+    barrier();
+  }
+
+private:
+  static void barrier()
+  {
+#if defined(__ARM_ARCH_4__) \
+    || defined(__ARM_ARCH_4T__) \
+    || defined(__ARM_ARCH_5__) \
+    || defined(__ARM_ARCH_5E__) \
+    || defined(__ARM_ARCH_5T__) \
+    || defined(__ARM_ARCH_5TE__) \
+    || defined(__ARM_ARCH_5TEJ__) \
+    || defined(__ARM_ARCH_6__) \
+    || defined(__ARM_ARCH_6J__) \
+    || defined(__ARM_ARCH_6K__) \
+    || defined(__ARM_ARCH_6Z__) \
+    || defined(__ARM_ARCH_6ZK__) \
+    || defined(__ARM_ARCH_6T2__)
+# if defined(__thumb__)
+    // This is just a placeholder and almost certainly not sufficient.
+    __asm__ __volatile__ ("" : : : "memory");
+# else // defined(__thumb__)
+    int a = 0, b = 0;
+    __asm__ __volatile__ ("swp %0, %1, [%2]"
+        : "=&r"(a) : "r"(1), "r"(&b) : "memory", "cc");
+# endif // defined(__thumb__)
+#else
+    // ARMv7 and later.
+    __asm__ __volatile__ ("dmb" : : : "memory");
+#endif
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(__GNUC__) && defined(__arm__)
+
+#endif // ASIO_DETAIL_GCC_ARM_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/gcc_hppa_fenced_block.hpp b/subprojects/asio/include/asio/detail/gcc_hppa_fenced_block.hpp
new file mode 100644
index 000000000..d3957ce33
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/gcc_hppa_fenced_block.hpp
@@ -0,0 +1,68 @@
+//
+// detail/gcc_hppa_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_GCC_HPPA_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_GCC_HPPA_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(__GNUC__) && (defined(__hppa) || defined(__hppa__))
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class gcc_hppa_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_t { half };
+  enum full_t { full };
+
+  // Constructor for a half fenced block.
+  explicit gcc_hppa_fenced_block(half_t)
+  {
+  }
+
+  // Constructor for a full fenced block.
+  explicit gcc_hppa_fenced_block(full_t)
+  {
+    barrier();
+  }
+
+  // Destructor.
+  ~gcc_hppa_fenced_block()
+  {
+    barrier();
+  }
+
+private:
+  static void barrier()
+  {
+    // This is just a placeholder and almost certainly not sufficient.
+    __asm__ __volatile__ ("" : : : "memory");
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(__GNUC__) && (defined(__hppa) || defined(__hppa__))
+
+#endif // ASIO_DETAIL_GCC_HPPA_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/gcc_sync_fenced_block.hpp b/subprojects/asio/include/asio/detail/gcc_sync_fenced_block.hpp
new file mode 100644
index 000000000..90d176f12
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/gcc_sync_fenced_block.hpp
@@ -0,0 +1,65 @@
+//
+// detail/gcc_sync_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_GCC_SYNC_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_GCC_SYNC_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(__GNUC__) \
+  && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)) \
+  && !defined(__INTEL_COMPILER) && !defined(__ICL) \
+  && !defined(__ICC) && !defined(__ECC) && !defined(__PATHSCALE__)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class gcc_sync_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_or_full_t { half, full };
+
+  // Constructor.
+  explicit gcc_sync_fenced_block(half_or_full_t)
+    : value_(0)
+  {
+    __sync_lock_test_and_set(&value_, 1);
+  }
+
+  // Destructor.
+  ~gcc_sync_fenced_block()
+  {
+    __sync_lock_release(&value_);
+  }
+
+private:
+  int value_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(__GNUC__)
+       // && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4))
+       // && !defined(__INTEL_COMPILER) && !defined(__ICL)
+       // && !defined(__ICC) && !defined(__ECC) && !defined(__PATHSCALE__)
+
+#endif // ASIO_DETAIL_GCC_SYNC_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/gcc_x86_fenced_block.hpp b/subprojects/asio/include/asio/detail/gcc_x86_fenced_block.hpp
new file mode 100644
index 000000000..1366def74
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/gcc_x86_fenced_block.hpp
@@ -0,0 +1,99 @@
+//
+// detail/gcc_x86_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_GCC_X86_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_GCC_X86_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class gcc_x86_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_t { half };
+  enum full_t { full };
+
+  // Constructor for a half fenced block.
+  explicit gcc_x86_fenced_block(half_t)
+  {
+  }
+
+  // Constructor for a full fenced block.
+  explicit gcc_x86_fenced_block(full_t)
+  {
+    lbarrier();
+  }
+
+  // Destructor.
+  ~gcc_x86_fenced_block()
+  {
+    sbarrier();
+  }
+
+private:
+  static int barrier()
+  {
+    int r = 0, m = 1;
+    __asm__ __volatile__ (
+        "xchgl %0, %1" :
+        "=r"(r), "=m"(m) :
+        "0"(1), "m"(m) :
+        "memory", "cc");
+    return r;
+  }
+
+  static void lbarrier()
+  {
+#if defined(__SSE2__)
+# if (__GNUC__ >= 4) && !defined(__INTEL_COMPILER) && !defined(__ICL)
+    __builtin_ia32_lfence();
+# else // (__GNUC__ >= 4) && !defined(__INTEL_COMPILER) && !defined(__ICL)
+    __asm__ __volatile__ ("lfence" ::: "memory");
+# endif // (__GNUC__ >= 4) && !defined(__INTEL_COMPILER) && !defined(__ICL)
+#else // defined(__SSE2__)
+    barrier();
+#endif // defined(__SSE2__)
+  }
+
+  static void sbarrier()
+  {
+#if defined(__SSE2__)
+# if (__GNUC__ >= 4) && !defined(__INTEL_COMPILER) && !defined(__ICL)
+    __builtin_ia32_sfence();
+# else // (__GNUC__ >= 4) && !defined(__INTEL_COMPILER) && !defined(__ICL)
+    __asm__ __volatile__ ("sfence" ::: "memory");
+# endif // (__GNUC__ >= 4) && !defined(__INTEL_COMPILER) && !defined(__ICL)
+#else // defined(__SSE2__)
+    barrier();
+#endif // defined(__SSE2__)
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+
+#endif // ASIO_DETAIL_GCC_X86_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/global.hpp b/subprojects/asio/include/asio/detail/global.hpp
new file mode 100644
index 000000000..085ac643d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/global.hpp
@@ -0,0 +1,52 @@
+//
+// detail/global.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_GLOBAL_HPP
+#define ASIO_DETAIL_GLOBAL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+# include "asio/detail/null_global.hpp"
+#elif defined(ASIO_WINDOWS)
+# include "asio/detail/win_global.hpp"
+#elif defined(ASIO_HAS_PTHREADS)
+# include "asio/detail/posix_global.hpp"
+#elif defined(ASIO_HAS_STD_CALL_ONCE)
+# include "asio/detail/std_global.hpp"
+#else
+# error Only Windows, POSIX and std::call_once are supported!
+#endif
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+inline T& global()
+{
+#if !defined(ASIO_HAS_THREADS)
+  return null_global<T>();
+#elif defined(ASIO_WINDOWS)
+  return win_global<T>();
+#elif defined(ASIO_HAS_PTHREADS)
+  return posix_global<T>();
+#elif defined(ASIO_HAS_STD_CALL_ONCE)
+  return std_global<T>();
+#endif
+}
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_GLOBAL_HPP
diff --git a/subprojects/asio/include/asio/detail/handler_alloc_helpers.hpp b/subprojects/asio/include/asio/detail/handler_alloc_helpers.hpp
new file mode 100644
index 000000000..afefb4d12
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/handler_alloc_helpers.hpp
@@ -0,0 +1,235 @@
+//
+// detail/handler_alloc_helpers.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_HANDLER_ALLOC_HELPERS_HPP
+#define ASIO_DETAIL_HANDLER_ALLOC_HELPERS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/recycling_allocator.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/handler_alloc_hook.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+// Calls to asio_handler_allocate and asio_handler_deallocate must be made from
+// a namespace that does not contain any overloads of these functions. The
+// asio_handler_alloc_helpers namespace is defined here for that purpose.
+namespace asio_handler_alloc_helpers {
+
+template <typename Handler>
+inline void* allocate(std::size_t s, Handler& h)
+{
+#if !defined(ASIO_HAS_HANDLER_HOOKS)
+  return ::operator new(s);
+#else
+  using asio::asio_handler_allocate;
+  return asio_handler_allocate(s, asio::detail::addressof(h));
+#endif
+}
+
+template <typename Handler>
+inline void deallocate(void* p, std::size_t s, Handler& h)
+{
+#if !defined(ASIO_HAS_HANDLER_HOOKS)
+  ::operator delete(p);
+#else
+  using asio::asio_handler_deallocate;
+  asio_handler_deallocate(p, s, asio::detail::addressof(h));
+#endif
+}
+
+} // namespace asio_handler_alloc_helpers
+
+namespace asio {
+namespace detail {
+
+template <typename Handler, typename T>
+class hook_allocator
+{
+public:
+  typedef T value_type;
+
+  template <typename U>
+  struct rebind
+  {
+    typedef hook_allocator<Handler, U> other;
+  };
+
+  explicit hook_allocator(Handler& h)
+    : handler_(h)
+  {
+  }
+
+  template <typename U>
+  hook_allocator(const hook_allocator<Handler, U>& a)
+    : handler_(a.handler_)
+  {
+  }
+
+  T* allocate(std::size_t n)
+  {
+    return static_cast<T*>(
+        asio_handler_alloc_helpers::allocate(sizeof(T) * n, handler_));
+  }
+
+  void deallocate(T* p, std::size_t n)
+  {
+    asio_handler_alloc_helpers::deallocate(p, sizeof(T) * n, handler_);
+  }
+
+//private:
+  Handler& handler_;
+};
+
+template <typename Handler>
+class hook_allocator<Handler, void>
+{
+public:
+  typedef void value_type;
+
+  template <typename U>
+  struct rebind
+  {
+    typedef hook_allocator<Handler, U> other;
+  };
+
+  explicit hook_allocator(Handler& h)
+    : handler_(h)
+  {
+  }
+
+  template <typename U>
+  hook_allocator(const hook_allocator<Handler, U>& a)
+    : handler_(a.handler_)
+  {
+  }
+
+//private:
+  Handler& handler_;
+};
+
+template <typename Handler, typename Allocator>
+struct get_hook_allocator
+{
+  typedef Allocator type;
+
+  static type get(Handler&, const Allocator& a)
+  {
+    return a;
+  }
+};
+
+template <typename Handler, typename T>
+struct get_hook_allocator<Handler, std::allocator<T> >
+{
+  typedef hook_allocator<Handler, T> type;
+
+  static type get(Handler& handler, const std::allocator<T>&)
+  {
+    return type(handler);
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#define ASIO_DEFINE_HANDLER_PTR(op) \
+  struct ptr \
+  { \
+    Handler* h; \
+    op* v; \
+    op* p; \
+    ~ptr() \
+    { \
+      reset(); \
+    } \
+    static op* allocate(Handler& handler) \
+    { \
+      typedef typename ::asio::associated_allocator< \
+        Handler>::type associated_allocator_type; \
+      typedef typename ::asio::detail::get_hook_allocator< \
+        Handler, associated_allocator_type>::type hook_allocator_type; \
+      ASIO_REBIND_ALLOC(hook_allocator_type, op) a( \
+            ::asio::detail::get_hook_allocator< \
+              Handler, associated_allocator_type>::get( \
+                handler, ::asio::get_associated_allocator(handler))); \
+      return a.allocate(1); \
+    } \
+    void reset() \
+    { \
+      if (p) \
+      { \
+        p->~op(); \
+        p = 0; \
+      } \
+      if (v) \
+      { \
+        typedef typename ::asio::associated_allocator< \
+          Handler>::type associated_allocator_type; \
+        typedef typename ::asio::detail::get_hook_allocator< \
+          Handler, associated_allocator_type>::type hook_allocator_type; \
+        ASIO_REBIND_ALLOC(hook_allocator_type, op) a( \
+              ::asio::detail::get_hook_allocator< \
+                Handler, associated_allocator_type>::get( \
+                  *h, ::asio::get_associated_allocator(*h))); \
+        a.deallocate(static_cast<op*>(v), 1); \
+        v = 0; \
+      } \
+    } \
+  } \
+  /**/
+
+#define ASIO_DEFINE_HANDLER_ALLOCATOR_PTR(op) \
+  struct ptr \
+  { \
+    const Alloc* a; \
+    void* v; \
+    op* p; \
+    ~ptr() \
+    { \
+      reset(); \
+    } \
+    static op* allocate(const Alloc& a) \
+    { \
+      typedef typename ::asio::detail::get_recycling_allocator< \
+        Alloc>::type recycling_allocator_type; \
+      ASIO_REBIND_ALLOC(recycling_allocator_type, op) a1( \
+            ::asio::detail::get_recycling_allocator<Alloc>::get(a)); \
+      return a1.allocate(1); \
+    } \
+    void reset() \
+    { \
+      if (p) \
+      { \
+        p->~op(); \
+        p = 0; \
+      } \
+      if (v) \
+      { \
+        typedef typename ::asio::detail::get_recycling_allocator< \
+          Alloc>::type recycling_allocator_type; \
+        ASIO_REBIND_ALLOC(recycling_allocator_type, op) a1( \
+              ::asio::detail::get_recycling_allocator<Alloc>::get(*a)); \
+        a1.deallocate(static_cast<op*>(v), 1); \
+        v = 0; \
+      } \
+    } \
+  } \
+  /**/
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_HANDLER_ALLOC_HELPERS_HPP
diff --git a/subprojects/asio/include/asio/detail/handler_cont_helpers.hpp b/subprojects/asio/include/asio/detail/handler_cont_helpers.hpp
new file mode 100644
index 000000000..110ba944f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/handler_cont_helpers.hpp
@@ -0,0 +1,45 @@
+//
+// detail/handler_cont_helpers.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_HANDLER_CONT_HELPERS_HPP
+#define ASIO_DETAIL_HANDLER_CONT_HELPERS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/handler_continuation_hook.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+// Calls to asio_handler_is_continuation must be made from a namespace that
+// does not contain overloads of this function. This namespace is defined here
+// for that purpose.
+namespace asio_handler_cont_helpers {
+
+template <typename Context>
+inline bool is_continuation(Context& context)
+{
+#if !defined(ASIO_HAS_HANDLER_HOOKS)
+  return false;
+#else
+  using asio::asio_handler_is_continuation;
+  return asio_handler_is_continuation(
+      asio::detail::addressof(context));
+#endif
+}
+
+} // namespace asio_handler_cont_helpers
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_HANDLER_CONT_HELPERS_HPP
diff --git a/subprojects/asio/include/asio/detail/handler_invoke_helpers.hpp b/subprojects/asio/include/asio/detail/handler_invoke_helpers.hpp
new file mode 100644
index 000000000..4c65c4c53
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/handler_invoke_helpers.hpp
@@ -0,0 +1,57 @@
+//
+// detail/handler_invoke_helpers.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_HANDLER_INVOKE_HELPERS_HPP
+#define ASIO_DETAIL_HANDLER_INVOKE_HELPERS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/handler_invoke_hook.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+// Calls to asio_handler_invoke must be made from a namespace that does not
+// contain overloads of this function. The asio_handler_invoke_helpers
+// namespace is defined here for that purpose.
+namespace asio_handler_invoke_helpers {
+
+template <typename Function, typename Context>
+inline void invoke(Function& function, Context& context)
+{
+#if !defined(ASIO_HAS_HANDLER_HOOKS)
+  Function tmp(function);
+  tmp();
+#else
+  using asio::asio_handler_invoke;
+  asio_handler_invoke(function, asio::detail::addressof(context));
+#endif
+}
+
+template <typename Function, typename Context>
+inline void invoke(const Function& function, Context& context)
+{
+#if !defined(ASIO_HAS_HANDLER_HOOKS)
+  Function tmp(function);
+  tmp();
+#else
+  using asio::asio_handler_invoke;
+  asio_handler_invoke(function, asio::detail::addressof(context));
+#endif
+}
+
+} // namespace asio_handler_invoke_helpers
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_HANDLER_INVOKE_HELPERS_HPP
diff --git a/subprojects/asio/include/asio/detail/handler_tracking.hpp b/subprojects/asio/include/asio/detail/handler_tracking.hpp
new file mode 100644
index 000000000..83f820eca
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/handler_tracking.hpp
@@ -0,0 +1,238 @@
+//
+// detail/handler_tracking.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_HANDLER_TRACKING_HPP
+#define ASIO_DETAIL_HANDLER_TRACKING_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+namespace asio {
+
+class execution_context;
+
+} // namespace asio
+
+#if defined(ASIO_CUSTOM_HANDLER_TRACKING)
+# include ASIO_CUSTOM_HANDLER_TRACKING
+#elif defined(ASIO_ENABLE_HANDLER_TRACKING)
+# include "asio/error_code.hpp"
+# include "asio/detail/cstdint.hpp"
+# include "asio/detail/static_mutex.hpp"
+# include "asio/detail/tss_ptr.hpp"
+#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_CUSTOM_HANDLER_TRACKING)
+
+// The user-specified header must define the following macros:
+// - ASIO_INHERIT_TRACKED_HANDLER
+// - ASIO_ALSO_INHERIT_TRACKED_HANDLER
+// - ASIO_HANDLER_TRACKING_INIT
+// - ASIO_HANDLER_CREATION(args)
+// - ASIO_HANDLER_COMPLETION(args)
+// - ASIO_HANDLER_INVOCATION_BEGIN(args)
+// - ASIO_HANDLER_INVOCATION_END
+// - ASIO_HANDLER_OPERATION(args)
+// - ASIO_HANDLER_REACTOR_REGISTRATION(args)
+// - ASIO_HANDLER_REACTOR_DEREGISTRATION(args)
+// - ASIO_HANDLER_REACTOR_READ_EVENT
+// - ASIO_HANDLER_REACTOR_WRITE_EVENT
+// - ASIO_HANDLER_REACTOR_ERROR_EVENT
+// - ASIO_HANDLER_REACTOR_EVENTS(args)
+// - ASIO_HANDLER_REACTOR_OPERATION(args)
+
+# if !defined(ASIO_ENABLE_HANDLER_TRACKING)
+#  define ASIO_ENABLE_HANDLER_TRACKING 1
+# endif /// !defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+#elif defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+class handler_tracking
+{
+public:
+  class completion;
+
+  // Base class for objects containing tracked handlers.
+  class tracked_handler
+  {
+  private:
+    // Only the handler_tracking class will have access to the id.
+    friend class handler_tracking;
+    friend class completion;
+    uint64_t id_;
+
+  protected:
+    // Constructor initialises with no id.
+    tracked_handler() : id_(0) {}
+
+    // Prevent deletion through this type.
+    ~tracked_handler() {}
+  };
+
+  // Initialise the tracking system.
+  ASIO_DECL static void init();
+
+  // Record the creation of a tracked handler.
+  ASIO_DECL static void creation(
+      execution_context& context, tracked_handler& h,
+      const char* object_type, void* object,
+      uintmax_t native_handle, const char* op_name);
+
+  class completion
+  {
+  public:
+    // Constructor records that handler is to be invoked with no arguments.
+    ASIO_DECL explicit completion(const tracked_handler& h);
+
+    // Destructor records only when an exception is thrown from the handler, or
+    // if the memory is being freed without the handler having been invoked.
+    ASIO_DECL ~completion();
+
+    // Records that handler is to be invoked with no arguments.
+    ASIO_DECL void invocation_begin();
+
+    // Records that handler is to be invoked with one arguments.
+    ASIO_DECL void invocation_begin(const asio::error_code& ec);
+
+    // Constructor records that handler is to be invoked with two arguments.
+    ASIO_DECL void invocation_begin(
+        const asio::error_code& ec, std::size_t bytes_transferred);
+
+    // Constructor records that handler is to be invoked with two arguments.
+    ASIO_DECL void invocation_begin(
+        const asio::error_code& ec, int signal_number);
+
+    // Constructor records that handler is to be invoked with two arguments.
+    ASIO_DECL void invocation_begin(
+        const asio::error_code& ec, const char* arg);
+
+    // Record that handler invocation has ended.
+    ASIO_DECL void invocation_end();
+
+  private:
+    friend class handler_tracking;
+    uint64_t id_;
+    bool invoked_;
+    completion* next_;
+  };
+
+  // Record an operation that is not directly associated with a handler.
+  ASIO_DECL static void operation(execution_context& context,
+      const char* object_type, void* object,
+      uintmax_t native_handle, const char* op_name);
+
+  // Record that a descriptor has been registered with the reactor.
+  ASIO_DECL static void reactor_registration(execution_context& context,
+      uintmax_t native_handle, uintmax_t registration);
+
+  // Record that a descriptor has been deregistered from the reactor.
+  ASIO_DECL static void reactor_deregistration(execution_context& context,
+      uintmax_t native_handle, uintmax_t registration);
+
+  // Record a reactor-based operation that is associated with a handler.
+  ASIO_DECL static void reactor_events(execution_context& context,
+      uintmax_t registration, unsigned events);
+
+  // Record a reactor-based operation that is associated with a handler.
+  ASIO_DECL static void reactor_operation(
+      const tracked_handler& h, const char* op_name,
+      const asio::error_code& ec);
+
+  // Record a reactor-based operation that is associated with a handler.
+  ASIO_DECL static void reactor_operation(
+      const tracked_handler& h, const char* op_name,
+      const asio::error_code& ec, std::size_t bytes_transferred);
+
+  // Write a line of output.
+  ASIO_DECL static void write_line(const char* format, ...);
+
+private:
+  struct tracking_state;
+  ASIO_DECL static tracking_state* get_state();
+};
+
+# define ASIO_INHERIT_TRACKED_HANDLER \
+  : public asio::detail::handler_tracking::tracked_handler
+
+# define ASIO_ALSO_INHERIT_TRACKED_HANDLER \
+  , public asio::detail::handler_tracking::tracked_handler
+
+# define ASIO_HANDLER_TRACKING_INIT \
+  asio::detail::handler_tracking::init()
+
+# define ASIO_HANDLER_CREATION(args) \
+  asio::detail::handler_tracking::creation args
+
+# define ASIO_HANDLER_COMPLETION(args) \
+  asio::detail::handler_tracking::completion tracked_completion args
+
+# define ASIO_HANDLER_INVOCATION_BEGIN(args) \
+  tracked_completion.invocation_begin args
+
+# define ASIO_HANDLER_INVOCATION_END \
+  tracked_completion.invocation_end()
+
+# define ASIO_HANDLER_OPERATION(args) \
+  asio::detail::handler_tracking::operation args
+
+# define ASIO_HANDLER_REACTOR_REGISTRATION(args) \
+  asio::detail::handler_tracking::reactor_registration args
+
+# define ASIO_HANDLER_REACTOR_DEREGISTRATION(args) \
+  asio::detail::handler_tracking::reactor_deregistration args
+
+# define ASIO_HANDLER_REACTOR_READ_EVENT 1
+# define ASIO_HANDLER_REACTOR_WRITE_EVENT 2
+# define ASIO_HANDLER_REACTOR_ERROR_EVENT 4
+
+# define ASIO_HANDLER_REACTOR_EVENTS(args) \
+  asio::detail::handler_tracking::reactor_events args
+
+# define ASIO_HANDLER_REACTOR_OPERATION(args) \
+  asio::detail::handler_tracking::reactor_operation args
+
+#else // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+# define ASIO_INHERIT_TRACKED_HANDLER
+# define ASIO_ALSO_INHERIT_TRACKED_HANDLER
+# define ASIO_HANDLER_TRACKING_INIT (void)0
+# define ASIO_HANDLER_CREATION(args) (void)0
+# define ASIO_HANDLER_COMPLETION(args) (void)0
+# define ASIO_HANDLER_INVOCATION_BEGIN(args) (void)0
+# define ASIO_HANDLER_INVOCATION_END (void)0
+# define ASIO_HANDLER_OPERATION(args) (void)0
+# define ASIO_HANDLER_REACTOR_REGISTRATION(args) (void)0
+# define ASIO_HANDLER_REACTOR_DEREGISTRATION(args) (void)0
+# define ASIO_HANDLER_REACTOR_READ_EVENT 0
+# define ASIO_HANDLER_REACTOR_WRITE_EVENT 0
+# define ASIO_HANDLER_REACTOR_ERROR_EVENT 0
+# define ASIO_HANDLER_REACTOR_EVENTS(args) (void)0
+# define ASIO_HANDLER_REACTOR_OPERATION(args) (void)0
+
+#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/handler_tracking.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_HANDLER_TRACKING_HPP
diff --git a/subprojects/asio/include/asio/detail/handler_type_requirements.hpp b/subprojects/asio/include/asio/detail/handler_type_requirements.hpp
new file mode 100644
index 000000000..9181bc515
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/handler_type_requirements.hpp
@@ -0,0 +1,556 @@
+//
+// detail/handler_type_requirements.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_HANDLER_TYPE_REQUIREMENTS_HPP
+#define ASIO_DETAIL_HANDLER_TYPE_REQUIREMENTS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+// Older versions of gcc have difficulty compiling the sizeof expressions where
+// we test the handler type requirements. We'll disable checking of handler type
+// requirements for those compilers, but otherwise enable it by default.
+#if !defined(ASIO_DISABLE_HANDLER_TYPE_REQUIREMENTS)
+# if !defined(__GNUC__) || (__GNUC__ >= 4)
+#  define ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS 1
+# endif // !defined(__GNUC__) || (__GNUC__ >= 4)
+#endif // !defined(ASIO_DISABLE_HANDLER_TYPE_REQUIREMENTS)
+
+// With C++0x we can use a combination of enhanced SFINAE and static_assert to
+// generate better template error messages. As this technique is not yet widely
+// portable, we'll only enable it for tested compilers.
+#if !defined(ASIO_DISABLE_HANDLER_TYPE_REQUIREMENTS_ASSERT)
+# if defined(__GNUC__)
+#  if ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+#   if defined(__GXX_EXPERIMENTAL_CXX0X__)
+#    define ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS_ASSERT 1
+#   endif // defined(__GXX_EXPERIMENTAL_CXX0X__)
+#  endif // ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)) || (__GNUC__ > 4)
+# endif // defined(__GNUC__)
+# if defined(ASIO_MSVC)
+#  if (_MSC_VER >= 1600)
+#   define ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS_ASSERT 1
+#  endif // (_MSC_VER >= 1600)
+# endif // defined(ASIO_MSVC)
+# if defined(__clang__)
+#  if __has_feature(__cxx_static_assert__)
+#   define ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS_ASSERT 1
+#  endif // __has_feature(cxx_static_assert)
+# endif // defined(__clang__)
+#endif // !defined(ASIO_DISABLE_HANDLER_TYPE_REQUIREMENTS)
+
+#if defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS)
+# include "asio/async_result.hpp"
+#endif // defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS)
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS)
+
+# if defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS_ASSERT)
+
+template <typename Handler>
+auto zero_arg_copyable_handler_test(Handler h, void*)
+  -> decltype(
+    sizeof(Handler(static_cast<const Handler&>(h))),
+    ((h)()),
+    char(0));
+
+template <typename Handler>
+char (&zero_arg_copyable_handler_test(Handler, ...))[2];
+
+template <typename Handler, typename Arg1>
+auto one_arg_handler_test(Handler h, Arg1* a1)
+  -> decltype(
+    sizeof(Handler(ASIO_MOVE_CAST(Handler)(h))),
+    ((h)(*a1)),
+    char(0));
+
+template <typename Handler>
+char (&one_arg_handler_test(Handler h, ...))[2];
+
+template <typename Handler, typename Arg1, typename Arg2>
+auto two_arg_handler_test(Handler h, Arg1* a1, Arg2* a2)
+  -> decltype(
+    sizeof(Handler(ASIO_MOVE_CAST(Handler)(h))),
+    ((h)(*a1, *a2)),
+    char(0));
+
+template <typename Handler>
+char (&two_arg_handler_test(Handler, ...))[2];
+
+template <typename Handler, typename Arg1, typename Arg2>
+auto two_arg_move_handler_test(Handler h, Arg1* a1, Arg2* a2)
+  -> decltype(
+    sizeof(Handler(ASIO_MOVE_CAST(Handler)(h))),
+    ((h)(*a1, ASIO_MOVE_CAST(Arg2)(*a2))),
+    char(0));
+
+template <typename Handler>
+char (&two_arg_move_handler_test(Handler, ...))[2];
+
+#  define ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT(expr, msg) \
+     static_assert(expr, msg);
+
+# else // defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS_ASSERT)
+
+#  define ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT(expr, msg)
+
+# endif // defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS_ASSERT)
+
+template <typename T> T& lvref();
+template <typename T> T& lvref(T);
+template <typename T> const T& clvref();
+template <typename T> const T& clvref(T);
+#if defined(ASIO_HAS_MOVE)
+template <typename T> T rvref();
+template <typename T> T rvref(T);
+#else // defined(ASIO_HAS_MOVE)
+template <typename T> const T& rvref();
+template <typename T> const T& rvref(T);
+#endif // defined(ASIO_HAS_MOVE)
+template <typename T> char argbyv(T);
+
+template <int>
+struct handler_type_requirements
+{
+};
+
+#define ASIO_LEGACY_COMPLETION_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void()) asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::zero_arg_copyable_handler_test( \
+          asio::detail::clvref< \
+            asio_true_handler_type>(), 0)) == 1, \
+      "CompletionHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::clvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()(), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_READ_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, std::size_t)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<const std::size_t*>(0))) == 1, \
+      "ReadHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>(), \
+            asio::detail::lvref<const std::size_t>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_WRITE_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, std::size_t)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<const std::size_t*>(0))) == 1, \
+      "WriteHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>(), \
+            asio::detail::lvref<const std::size_t>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_ACCEPT_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::one_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0))) == 1, \
+      "AcceptHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_MOVE_ACCEPT_HANDLER_CHECK( \
+    handler_type, handler, socket_type) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, socket_type)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_move_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<socket_type*>(0))) == 1, \
+      "MoveAcceptHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>(), \
+            asio::detail::rvref<socket_type>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_CONNECT_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::one_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0))) == 1, \
+      "ConnectHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_RANGE_CONNECT_HANDLER_CHECK( \
+    handler_type, handler, endpoint_type) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, endpoint_type)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<const endpoint_type*>(0))) == 1, \
+      "RangeConnectHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>(), \
+            asio::detail::lvref<const endpoint_type>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_ITERATOR_CONNECT_HANDLER_CHECK( \
+    handler_type, handler, iter_type) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, iter_type)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<const iter_type*>(0))) == 1, \
+      "IteratorConnectHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>(), \
+            asio::detail::lvref<const iter_type>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_RESOLVE_HANDLER_CHECK( \
+    handler_type, handler, range_type) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, range_type)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<const range_type*>(0))) == 1, \
+      "ResolveHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>(), \
+            asio::detail::lvref<const range_type>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_WAIT_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::one_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0))) == 1, \
+      "WaitHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_SIGNAL_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, int)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<const int*>(0))) == 1, \
+      "SignalHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>(), \
+            asio::detail::lvref<const int>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_HANDSHAKE_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::one_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0))) == 1, \
+      "HandshakeHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_BUFFERED_HANDSHAKE_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code, std::size_t)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::two_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0), \
+          static_cast<const std::size_t*>(0))) == 1, \
+      "BufferedHandshakeHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+          asio::detail::lvref<const asio::error_code>(), \
+          asio::detail::lvref<const std::size_t>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#define ASIO_SHUTDOWN_HANDLER_CHECK( \
+    handler_type, handler) \
+  \
+  typedef ASIO_HANDLER_TYPE(handler_type, \
+      void(asio::error_code)) \
+    asio_true_handler_type; \
+  \
+  ASIO_HANDLER_TYPE_REQUIREMENTS_ASSERT( \
+      sizeof(asio::detail::one_arg_handler_test( \
+          asio::detail::rvref< \
+            asio_true_handler_type>(), \
+          static_cast<const asio::error_code*>(0))) == 1, \
+      "ShutdownHandler type requirements not met") \
+  \
+  typedef asio::detail::handler_type_requirements< \
+      sizeof( \
+        asio::detail::argbyv( \
+          asio::detail::rvref< \
+            asio_true_handler_type>())) + \
+      sizeof( \
+        asio::detail::lvref< \
+          asio_true_handler_type>()( \
+            asio::detail::lvref<const asio::error_code>()), \
+        char(0))> ASIO_UNUSED_TYPEDEF
+
+#else // !defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS)
+
+#define ASIO_LEGACY_COMPLETION_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_READ_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_WRITE_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_ACCEPT_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_MOVE_ACCEPT_HANDLER_CHECK( \
+    handler_type, handler, socket_type) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_CONNECT_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_RANGE_CONNECT_HANDLER_CHECK( \
+    handler_type, handler, iter_type) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_ITERATOR_CONNECT_HANDLER_CHECK( \
+    handler_type, handler, iter_type) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_RESOLVE_HANDLER_CHECK( \
+    handler_type, handler, iter_type) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_WAIT_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_SIGNAL_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_HANDSHAKE_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_BUFFERED_HANDSHAKE_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#define ASIO_SHUTDOWN_HANDLER_CHECK( \
+    handler_type, handler) \
+  typedef int ASIO_UNUSED_TYPEDEF
+
+#endif // !defined(ASIO_ENABLE_HANDLER_TYPE_REQUIREMENTS)
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_HANDLER_TYPE_REQUIREMENTS_HPP
diff --git a/subprojects/asio/include/asio/detail/handler_work.hpp b/subprojects/asio/include/asio/detail/handler_work.hpp
new file mode 100644
index 000000000..cce5c4b6d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/handler_work.hpp
@@ -0,0 +1,95 @@
+//
+// detail/handler_work.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_HANDLER_WORK_HPP
+#define ASIO_DETAIL_HANDLER_WORK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// A helper class template to allow completion handlers to be dispatched
+// through either the new executors framework or the old invocaton hook. The
+// primary template uses the new executors framework.
+template <typename Handler, typename Executor
+    = typename associated_executor<Handler>::type>
+class handler_work
+{
+public:
+  explicit handler_work(Handler& handler) ASIO_NOEXCEPT
+    : executor_(associated_executor<Handler>::get(handler))
+  {
+  }
+
+  static void start(Handler& handler) ASIO_NOEXCEPT
+  {
+    Executor ex(associated_executor<Handler>::get(handler));
+    ex.on_work_started();
+  }
+
+  ~handler_work()
+  {
+    executor_.on_work_finished();
+  }
+
+  template <typename Function>
+  void complete(Function& function, Handler& handler)
+  {
+    executor_.dispatch(ASIO_MOVE_CAST(Function)(function),
+        associated_allocator<Handler>::get(handler));
+  }
+
+private:
+  // Disallow copying and assignment.
+  handler_work(const handler_work&);
+  handler_work& operator=(const handler_work&);
+
+  typename associated_executor<Handler>::type executor_;
+};
+
+// This specialisation dispatches a handler through the old invocation hook.
+// The specialisation is not strictly required for correctness, as the
+// system_executor will dispatch through the hook anyway. However, by doing
+// this we avoid an extra copy of the handler.
+template <typename Handler>
+class handler_work<Handler, system_executor>
+{
+public:
+  explicit handler_work(Handler&) ASIO_NOEXCEPT {}
+  static void start(Handler&) ASIO_NOEXCEPT {}
+  ~handler_work() {}
+
+  template <typename Function>
+  void complete(Function& function, Handler& handler)
+  {
+    asio_handler_invoke_helpers::invoke(function, handler);
+  }
+
+private:
+  // Disallow copying and assignment.
+  handler_work(const handler_work&);
+  handler_work& operator=(const handler_work&);
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_HANDLER_WORK_HPP
diff --git a/subprojects/asio/include/asio/detail/hash_map.hpp b/subprojects/asio/include/asio/detail/hash_map.hpp
new file mode 100644
index 000000000..e70970d6b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/hash_map.hpp
@@ -0,0 +1,331 @@
+//
+// detail/hash_map.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_HASH_MAP_HPP
+#define ASIO_DETAIL_HASH_MAP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <list>
+#include <utility>
+#include "asio/detail/assert.hpp"
+#include "asio/detail/noncopyable.hpp"
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# include "asio/detail/socket_types.hpp"
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+inline std::size_t calculate_hash_value(int i)
+{
+  return static_cast<std::size_t>(i);
+}
+
+inline std::size_t calculate_hash_value(void* p)
+{
+  return reinterpret_cast<std::size_t>(p)
+    + (reinterpret_cast<std::size_t>(p) >> 3);
+}
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+inline std::size_t calculate_hash_value(SOCKET s)
+{
+  return static_cast<std::size_t>(s);
+}
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+// Note: assumes K and V are POD types.
+template <typename K, typename V>
+class hash_map
+  : private noncopyable
+{
+public:
+  // The type of a value in the map.
+  typedef std::pair<K, V> value_type;
+
+  // The type of a non-const iterator over the hash map.
+  typedef typename std::list<value_type>::iterator iterator;
+
+  // The type of a const iterator over the hash map.
+  typedef typename std::list<value_type>::const_iterator const_iterator;
+
+  // Constructor.
+  hash_map()
+    : size_(0),
+      buckets_(0),
+      num_buckets_(0)
+  {
+  }
+
+  // Destructor.
+  ~hash_map()
+  {
+    delete[] buckets_;
+  }
+
+  // Get an iterator for the beginning of the map.
+  iterator begin()
+  {
+    return values_.begin();
+  }
+
+  // Get an iterator for the beginning of the map.
+  const_iterator begin() const
+  {
+    return values_.begin();
+  }
+
+  // Get an iterator for the end of the map.
+  iterator end()
+  {
+    return values_.end();
+  }
+
+  // Get an iterator for the end of the map.
+  const_iterator end() const
+  {
+    return values_.end();
+  }
+
+  // Check whether the map is empty.
+  bool empty() const
+  {
+    return values_.empty();
+  }
+
+  // Find an entry in the map.
+  iterator find(const K& k)
+  {
+    if (num_buckets_)
+    {
+      size_t bucket = calculate_hash_value(k) % num_buckets_;
+      iterator it = buckets_[bucket].first;
+      if (it == values_.end())
+        return values_.end();
+      iterator end_it = buckets_[bucket].last;
+      ++end_it;
+      while (it != end_it)
+      {
+        if (it->first == k)
+          return it;
+        ++it;
+      }
+    }
+    return values_.end();
+  }
+
+  // Find an entry in the map.
+  const_iterator find(const K& k) const
+  {
+    if (num_buckets_)
+    {
+      size_t bucket = calculate_hash_value(k) % num_buckets_;
+      const_iterator it = buckets_[bucket].first;
+      if (it == values_.end())
+        return it;
+      const_iterator end_it = buckets_[bucket].last;
+      ++end_it;
+      while (it != end_it)
+      {
+        if (it->first == k)
+          return it;
+        ++it;
+      }
+    }
+    return values_.end();
+  }
+
+  // Insert a new entry into the map.
+  std::pair<iterator, bool> insert(const value_type& v)
+  {
+    if (size_ + 1 >= num_buckets_)
+      rehash(hash_size(size_ + 1));
+    size_t bucket = calculate_hash_value(v.first) % num_buckets_;
+    iterator it = buckets_[bucket].first;
+    if (it == values_.end())
+    {
+      buckets_[bucket].first = buckets_[bucket].last =
+        values_insert(values_.end(), v);
+      ++size_;
+      return std::pair<iterator, bool>(buckets_[bucket].last, true);
+    }
+    iterator end_it = buckets_[bucket].last;
+    ++end_it;
+    while (it != end_it)
+    {
+      if (it->first == v.first)
+        return std::pair<iterator, bool>(it, false);
+      ++it;
+    }
+    buckets_[bucket].last = values_insert(end_it, v);
+    ++size_;
+    return std::pair<iterator, bool>(buckets_[bucket].last, true);
+  }
+
+  // Erase an entry from the map.
+  void erase(iterator it)
+  {
+    ASIO_ASSERT(it != values_.end());
+    ASIO_ASSERT(num_buckets_ != 0);
+
+    size_t bucket = calculate_hash_value(it->first) % num_buckets_;
+    bool is_first = (it == buckets_[bucket].first);
+    bool is_last = (it == buckets_[bucket].last);
+    if (is_first && is_last)
+      buckets_[bucket].first = buckets_[bucket].last = values_.end();
+    else if (is_first)
+      ++buckets_[bucket].first;
+    else if (is_last)
+      --buckets_[bucket].last;
+
+    values_erase(it);
+    --size_;
+  }
+
+  // Erase a key from the map.
+  void erase(const K& k)
+  {
+    iterator it = find(k);
+    if (it != values_.end())
+      erase(it);
+  }
+
+  // Remove all entries from the map.
+  void clear()
+  {
+    // Clear the values.
+    values_.clear();
+    size_ = 0;
+
+    // Initialise all buckets to empty.
+    iterator end_it = values_.end();
+    for (size_t i = 0; i < num_buckets_; ++i)
+      buckets_[i].first = buckets_[i].last = end_it;
+  }
+
+private:
+  // Calculate the hash size for the specified number of elements.
+  static std::size_t hash_size(std::size_t num_elems)
+  {
+    static std::size_t sizes[] =
+    {
+#if defined(ASIO_HASH_MAP_BUCKETS)
+      ASIO_HASH_MAP_BUCKETS
+#else // ASIO_HASH_MAP_BUCKETS
+      3, 13, 23, 53, 97, 193, 389, 769, 1543, 3079, 6151, 12289, 24593,
+      49157, 98317, 196613, 393241, 786433, 1572869, 3145739, 6291469,
+      12582917, 25165843
+#endif // ASIO_HASH_MAP_BUCKETS
+    };
+    const std::size_t nth_size = sizeof(sizes) / sizeof(std::size_t) - 1;
+    for (std::size_t i = 0; i < nth_size; ++i)
+      if (num_elems < sizes[i])
+        return sizes[i];
+    return sizes[nth_size];
+  }
+
+  // Re-initialise the hash from the values already contained in the list.
+  void rehash(std::size_t num_buckets)
+  {
+    if (num_buckets == num_buckets_)
+      return;
+    ASIO_ASSERT(num_buckets != 0);
+
+    iterator end_iter = values_.end();
+
+    // Update number of buckets and initialise all buckets to empty.
+    bucket_type* tmp = new bucket_type[num_buckets];
+    delete[] buckets_;
+    buckets_ = tmp;
+    num_buckets_ = num_buckets;
+    for (std::size_t i = 0; i < num_buckets_; ++i)
+      buckets_[i].first = buckets_[i].last = end_iter;
+
+    // Put all values back into the hash.
+    iterator iter = values_.begin();
+    while (iter != end_iter)
+    {
+      std::size_t bucket = calculate_hash_value(iter->first) % num_buckets_;
+      if (buckets_[bucket].last == end_iter)
+      {
+        buckets_[bucket].first = buckets_[bucket].last = iter++;
+      }
+      else if (++buckets_[bucket].last == iter)
+      {
+        ++iter;
+      }
+      else
+      {
+        values_.splice(buckets_[bucket].last, values_, iter++);
+        --buckets_[bucket].last;
+      }
+    }
+  }
+
+  // Insert an element into the values list by splicing from the spares list,
+  // if a spare is available, and otherwise by inserting a new element.
+  iterator values_insert(iterator it, const value_type& v)
+  {
+    if (spares_.empty())
+    {
+      return values_.insert(it, v);
+    }
+    else
+    {
+      spares_.front() = v;
+      values_.splice(it, spares_, spares_.begin());
+      return --it;
+    }
+  }
+
+  // Erase an element from the values list by splicing it to the spares list.
+  void values_erase(iterator it)
+  {
+    *it = value_type();
+    spares_.splice(spares_.begin(), values_, it);
+  }
+
+  // The number of elements in the hash.
+  std::size_t size_;
+
+  // The list of all values in the hash map.
+  std::list<value_type> values_;
+
+  // The list of spare nodes waiting to be recycled. Assumes that POD types only
+  // are stored in the hash map.
+  std::list<value_type> spares_;
+
+  // The type for a bucket in the hash table.
+  struct bucket_type
+  {
+    iterator first;
+    iterator last;
+  };
+
+  // The buckets in the hash.
+  bucket_type* buckets_;
+
+  // The number of buckets in the hash.
+  std::size_t num_buckets_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_HASH_MAP_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/buffer_sequence_adapter.ipp b/subprojects/asio/include/asio/detail/impl/buffer_sequence_adapter.ipp
new file mode 100644
index 000000000..323c8adb5
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/buffer_sequence_adapter.ipp
@@ -0,0 +1,118 @@
+//
+// detail/impl/buffer_sequence_adapter.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_BUFFER_SEQUENCE_ADAPTER_IPP
+#define ASIO_DETAIL_IMPL_BUFFER_SEQUENCE_ADAPTER_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include <robuffer.h>
+#include <windows.storage.streams.h>
+#include <wrl/implements.h>
+#include "asio/detail/buffer_sequence_adapter.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class winrt_buffer_impl :
+  public Microsoft::WRL::RuntimeClass<
+    Microsoft::WRL::RuntimeClassFlags<
+      Microsoft::WRL::RuntimeClassType::WinRtClassicComMix>,
+    ABI::Windows::Storage::Streams::IBuffer,
+    Windows::Storage::Streams::IBufferByteAccess>
+{
+public:
+  explicit winrt_buffer_impl(const asio::const_buffer& b)
+  {
+    bytes_ = const_cast<byte*>(static_cast<const byte*>(b.data()));
+    length_ = b.size();
+    capacity_ = b.size();
+  }
+
+  explicit winrt_buffer_impl(const asio::mutable_buffer& b)
+  {
+    bytes_ = static_cast<byte*>(b.data());
+    length_ = 0;
+    capacity_ = b.size();
+  }
+
+  ~winrt_buffer_impl()
+  {
+  }
+
+  STDMETHODIMP Buffer(byte** value)
+  {
+    *value = bytes_;
+    return S_OK;
+  }
+
+  STDMETHODIMP get_Capacity(UINT32* value)
+  {
+    *value = capacity_;
+    return S_OK;
+  }
+
+  STDMETHODIMP get_Length(UINT32 *value)
+  {
+    *value = length_;
+    return S_OK;
+  }
+
+  STDMETHODIMP put_Length(UINT32 value)
+  {
+    if (value > capacity_)
+      return E_INVALIDARG;
+    length_ = value;
+    return S_OK;
+  }
+
+private:
+  byte* bytes_;
+  UINT32 length_;
+  UINT32 capacity_;
+};
+
+void buffer_sequence_adapter_base::init_native_buffer(
+    buffer_sequence_adapter_base::native_buffer_type& buf,
+    const asio::mutable_buffer& buffer)
+{
+  std::memset(&buf, 0, sizeof(native_buffer_type));
+  Microsoft::WRL::ComPtr<IInspectable> insp
+    = Microsoft::WRL::Make<winrt_buffer_impl>(buffer);
+  buf = reinterpret_cast<Windows::Storage::Streams::IBuffer^>(insp.Get());
+}
+
+void buffer_sequence_adapter_base::init_native_buffer(
+    buffer_sequence_adapter_base::native_buffer_type& buf,
+    const asio::const_buffer& buffer)
+{
+  std::memset(&buf, 0, sizeof(native_buffer_type));
+  Microsoft::WRL::ComPtr<IInspectable> insp
+    = Microsoft::WRL::Make<winrt_buffer_impl>(buffer);
+  Platform::Object^ buf_obj = reinterpret_cast<Platform::Object^>(insp.Get());
+  buf = reinterpret_cast<Windows::Storage::Streams::IBuffer^>(insp.Get());
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_IMPL_BUFFER_SEQUENCE_ADAPTER_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/descriptor_ops.ipp b/subprojects/asio/include/asio/detail/impl/descriptor_ops.ipp
new file mode 100644
index 000000000..1af643fb5
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/descriptor_ops.ipp
@@ -0,0 +1,474 @@
+//
+// detail/impl/descriptor_ops.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
+#define ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cerrno>
+#include "asio/detail/descriptor_ops.hpp"
+#include "asio/error.hpp"
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace descriptor_ops {
+
+int open(const char* path, int flags, asio::error_code& ec)
+{
+  errno = 0;
+  int result = error_wrapper(::open(path, flags), ec);
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int close(int d, state_type& state, asio::error_code& ec)
+{
+  int result = 0;
+  if (d != -1)
+  {
+    errno = 0;
+    result = error_wrapper(::close(d), ec);
+
+    if (result != 0
+        && (ec == asio::error::would_block
+          || ec == asio::error::try_again))
+    {
+      // According to UNIX Network Programming Vol. 1, it is possible for
+      // close() to fail with EWOULDBLOCK under certain circumstances. What
+      // isn't clear is the state of the descriptor after this error. The one
+      // current OS where this behaviour is seen, Windows, says that the socket
+      // remains open. Therefore we'll put the descriptor back into blocking
+      // mode and have another attempt at closing it.
+#if defined(__SYMBIAN32__)
+      int flags = ::fcntl(d, F_GETFL, 0);
+      if (flags >= 0)
+        ::fcntl(d, F_SETFL, flags & ~O_NONBLOCK);
+#else // defined(__SYMBIAN32__)
+      ioctl_arg_type arg = 0;
+      ::ioctl(d, FIONBIO, &arg);
+#endif // defined(__SYMBIAN32__)
+      state &= ~non_blocking;
+
+      errno = 0;
+      result = error_wrapper(::close(d), ec);
+    }
+  }
+
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+}
+
+bool set_user_non_blocking(int d, state_type& state,
+    bool value, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return false;
+  }
+
+  errno = 0;
+#if defined(__SYMBIAN32__)
+  int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
+  if (result >= 0)
+  {
+    errno = 0;
+    int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
+    result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
+  }
+#else // defined(__SYMBIAN32__)
+  ioctl_arg_type arg = (value ? 1 : 0);
+  int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
+#endif // defined(__SYMBIAN32__)
+
+  if (result >= 0)
+  {
+    ec = asio::error_code();
+    if (value)
+      state |= user_set_non_blocking;
+    else
+    {
+      // Clearing the user-set non-blocking mode always overrides any
+      // internally-set non-blocking flag. Any subsequent asynchronous
+      // operations will need to re-enable non-blocking I/O.
+      state &= ~(user_set_non_blocking | internal_non_blocking);
+    }
+    return true;
+  }
+
+  return false;
+}
+
+bool set_internal_non_blocking(int d, state_type& state,
+    bool value, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return false;
+  }
+
+  if (!value && (state & user_set_non_blocking))
+  {
+    // It does not make sense to clear the internal non-blocking flag if the
+    // user still wants non-blocking behaviour. Return an error and let the
+    // caller figure out whether to update the user-set non-blocking flag.
+    ec = asio::error::invalid_argument;
+    return false;
+  }
+
+  errno = 0;
+#if defined(__SYMBIAN32__)
+  int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
+  if (result >= 0)
+  {
+    errno = 0;
+    int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
+    result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
+  }
+#else // defined(__SYMBIAN32__)
+  ioctl_arg_type arg = (value ? 1 : 0);
+  int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
+#endif // defined(__SYMBIAN32__)
+
+  if (result >= 0)
+  {
+    ec = asio::error_code();
+    if (value)
+      state |= internal_non_blocking;
+    else
+      state &= ~internal_non_blocking;
+    return true;
+  }
+
+  return false;
+}
+
+std::size_t sync_read(int d, state_type state, buf* bufs,
+    std::size_t count, bool all_empty, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // A request to read 0 bytes on a stream is a no-op.
+  if (all_empty)
+  {
+    ec = asio::error_code();
+    return 0;
+  }
+
+  // Read some data.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    errno = 0;
+    signed_size_type bytes = error_wrapper(::readv(
+          d, bufs, static_cast<int>(count)), ec);
+
+    // Check if operation succeeded.
+    if (bytes > 0)
+      return bytes;
+
+    // Check for EOF.
+    if (bytes == 0)
+    {
+      ec = asio::error::eof;
+      return 0;
+    }
+
+    // Operation failed.
+    if ((state & user_set_non_blocking)
+        || (ec != asio::error::would_block
+          && ec != asio::error::try_again))
+      return 0;
+
+    // Wait for descriptor to become ready.
+    if (descriptor_ops::poll_read(d, 0, ec) < 0)
+      return 0;
+  }
+}
+
+bool non_blocking_read(int d, buf* bufs, std::size_t count,
+    asio::error_code& ec, std::size_t& bytes_transferred)
+{
+  for (;;)
+  {
+    // Read some data.
+    errno = 0;
+    signed_size_type bytes = error_wrapper(::readv(
+          d, bufs, static_cast<int>(count)), ec);
+
+    // Check for end of stream.
+    if (bytes == 0)
+    {
+      ec = asio::error::eof;
+      return true;
+    }
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Check if we need to run the operation again.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+      return false;
+
+    // Operation is complete.
+    if (bytes > 0)
+    {
+      ec = asio::error_code();
+      bytes_transferred = bytes;
+    }
+    else
+      bytes_transferred = 0;
+
+    return true;
+  }
+}
+
+std::size_t sync_write(int d, state_type state, const buf* bufs,
+    std::size_t count, bool all_empty, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // A request to write 0 bytes on a stream is a no-op.
+  if (all_empty)
+  {
+    ec = asio::error_code();
+    return 0;
+  }
+
+  // Write some data.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    errno = 0;
+    signed_size_type bytes = error_wrapper(::writev(
+          d, bufs, static_cast<int>(count)), ec);
+
+    // Check if operation succeeded.
+    if (bytes > 0)
+      return bytes;
+
+    // Operation failed.
+    if ((state & user_set_non_blocking)
+        || (ec != asio::error::would_block
+          && ec != asio::error::try_again))
+      return 0;
+
+    // Wait for descriptor to become ready.
+    if (descriptor_ops::poll_write(d, 0, ec) < 0)
+      return 0;
+  }
+}
+
+bool non_blocking_write(int d, const buf* bufs, std::size_t count,
+    asio::error_code& ec, std::size_t& bytes_transferred)
+{
+  for (;;)
+  {
+    // Write some data.
+    errno = 0;
+    signed_size_type bytes = error_wrapper(::writev(
+          d, bufs, static_cast<int>(count)), ec);
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Check if we need to run the operation again.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+      return false;
+
+    // Operation is complete.
+    if (bytes >= 0)
+    {
+      ec = asio::error_code();
+      bytes_transferred = bytes;
+    }
+    else
+      bytes_transferred = 0;
+
+    return true;
+  }
+}
+
+int ioctl(int d, state_type& state, long cmd,
+    ioctl_arg_type* arg, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return -1;
+  }
+
+  errno = 0;
+  int result = error_wrapper(::ioctl(d, cmd, arg), ec);
+
+  if (result >= 0)
+  {
+    ec = asio::error_code();
+
+    // When updating the non-blocking mode we always perform the ioctl syscall,
+    // even if the flags would otherwise indicate that the descriptor is
+    // already in the correct state. This ensures that the underlying
+    // descriptor is put into the state that has been requested by the user. If
+    // the ioctl syscall was successful then we need to update the flags to
+    // match.
+    if (cmd == static_cast<long>(FIONBIO))
+    {
+      if (*arg)
+      {
+        state |= user_set_non_blocking;
+      }
+      else
+      {
+        // Clearing the non-blocking mode always overrides any internally-set
+        // non-blocking flag. Any subsequent asynchronous operations will need
+        // to re-enable non-blocking I/O.
+        state &= ~(user_set_non_blocking | internal_non_blocking);
+      }
+    }
+  }
+
+  return result;
+}
+
+int fcntl(int d, int cmd, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return -1;
+  }
+
+  errno = 0;
+  int result = error_wrapper(::fcntl(d, cmd), ec);
+  if (result != -1)
+    ec = asio::error_code();
+  return result;
+}
+
+int fcntl(int d, int cmd, long arg, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return -1;
+  }
+
+  errno = 0;
+  int result = error_wrapper(::fcntl(d, cmd, arg), ec);
+  if (result != -1)
+    ec = asio::error_code();
+  return result;
+}
+
+int poll_read(int d, state_type state, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return -1;
+  }
+
+  pollfd fds;
+  fds.fd = d;
+  fds.events = POLLIN;
+  fds.revents = 0;
+  int timeout = (state & user_set_non_blocking) ? 0 : -1;
+  errno = 0;
+  int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+  if (result == 0)
+    ec = (state & user_set_non_blocking)
+      ? asio::error::would_block : asio::error_code();
+  else if (result > 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int poll_write(int d, state_type state, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return -1;
+  }
+
+  pollfd fds;
+  fds.fd = d;
+  fds.events = POLLOUT;
+  fds.revents = 0;
+  int timeout = (state & user_set_non_blocking) ? 0 : -1;
+  errno = 0;
+  int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+  if (result == 0)
+    ec = (state & user_set_non_blocking)
+      ? asio::error::would_block : asio::error_code();
+  else if (result > 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int poll_error(int d, state_type state, asio::error_code& ec)
+{
+  if (d == -1)
+  {
+    ec = asio::error::bad_descriptor;
+    return -1;
+  }
+
+  pollfd fds;
+  fds.fd = d;
+  fds.events = POLLPRI | POLLERR | POLLHUP;
+  fds.revents = 0;
+  int timeout = (state & user_set_non_blocking) ? 0 : -1;
+  errno = 0;
+  int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+  if (result == 0)
+    ec = (state & user_set_non_blocking)
+      ? asio::error::would_block : asio::error_code();
+  else if (result > 0)
+    ec = asio::error_code();
+  return result;
+}
+
+} // namespace descriptor_ops
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/dev_poll_reactor.hpp b/subprojects/asio/include/asio/detail/impl/dev_poll_reactor.hpp
new file mode 100644
index 000000000..4cd8aafec
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/dev_poll_reactor.hpp
@@ -0,0 +1,91 @@
+//
+// detail/impl/dev_poll_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_HPP
+#define ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_DEV_POLL)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+void dev_poll_reactor::add_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_add_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void dev_poll_reactor::remove_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_remove_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void dev_poll_reactor::schedule_timer(timer_queue<Time_Traits>& queue,
+    const typename Time_Traits::time_type& time,
+    typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  if (shutdown_)
+  {
+    scheduler_.post_immediate_completion(op, false);
+    return;
+  }
+
+  bool earliest = queue.enqueue_timer(time, timer, op);
+  scheduler_.work_started();
+  if (earliest)
+    interrupter_.interrupt();
+}
+
+template <typename Time_Traits>
+std::size_t dev_poll_reactor::cancel_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& timer,
+    std::size_t max_cancelled)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  std::size_t n = queue.cancel_timer(timer, ops, max_cancelled);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+  return n;
+}
+
+template <typename Time_Traits>
+void dev_poll_reactor::move_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& target,
+    typename timer_queue<Time_Traits>::per_timer_data& source)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  queue.cancel_timer(target, ops);
+  queue.move_timer(target, source);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_DEV_POLL)
+
+#endif // ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/dev_poll_reactor.ipp b/subprojects/asio/include/asio/detail/impl/dev_poll_reactor.ipp
new file mode 100644
index 000000000..1ca376c1c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/dev_poll_reactor.ipp
@@ -0,0 +1,446 @@
+//
+// detail/impl/dev_poll_reactor.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_IPP
+#define ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_DEV_POLL)
+
+#include "asio/detail/dev_poll_reactor.hpp"
+#include "asio/detail/assert.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+dev_poll_reactor::dev_poll_reactor(asio::execution_context& ctx)
+  : asio::detail::execution_context_service_base<dev_poll_reactor>(ctx),
+    scheduler_(use_service<scheduler>(ctx)),
+    mutex_(),
+    dev_poll_fd_(do_dev_poll_create()),
+    interrupter_(),
+    shutdown_(false)
+{
+  // Add the interrupter's descriptor to /dev/poll.
+  ::pollfd ev = { 0, 0, 0 };
+  ev.fd = interrupter_.read_descriptor();
+  ev.events = POLLIN | POLLERR;
+  ev.revents = 0;
+  ::write(dev_poll_fd_, &ev, sizeof(ev));
+}
+
+dev_poll_reactor::~dev_poll_reactor()
+{
+  shutdown();
+  ::close(dev_poll_fd_);
+}
+
+void dev_poll_reactor::shutdown()
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  shutdown_ = true;
+  lock.unlock();
+
+  op_queue<operation> ops;
+
+  for (int i = 0; i < max_ops; ++i)
+    op_queue_[i].get_all_operations(ops);
+
+  timer_queues_.get_all_timers(ops);
+
+  scheduler_.abandon_operations(ops);
+} 
+
+void dev_poll_reactor::notify_fork(
+    asio::execution_context::fork_event fork_ev)
+{
+  if (fork_ev == asio::execution_context::fork_child)
+  {
+    detail::mutex::scoped_lock lock(mutex_);
+
+    if (dev_poll_fd_ != -1)
+      ::close(dev_poll_fd_);
+    dev_poll_fd_ = -1;
+    dev_poll_fd_ = do_dev_poll_create();
+
+    interrupter_.recreate();
+
+    // Add the interrupter's descriptor to /dev/poll.
+    ::pollfd ev = { 0, 0, 0 };
+    ev.fd = interrupter_.read_descriptor();
+    ev.events = POLLIN | POLLERR;
+    ev.revents = 0;
+    ::write(dev_poll_fd_, &ev, sizeof(ev));
+
+    // Re-register all descriptors with /dev/poll. The changes will be written
+    // to the /dev/poll descriptor the next time the reactor is run.
+    for (int i = 0; i < max_ops; ++i)
+    {
+      reactor_op_queue<socket_type>::iterator iter = op_queue_[i].begin();
+      reactor_op_queue<socket_type>::iterator end = op_queue_[i].end();
+      for (; iter != end; ++iter)
+      {
+        ::pollfd& pending_ev = add_pending_event_change(iter->first);
+        pending_ev.events |= POLLERR | POLLHUP;
+        switch (i)
+        {
+        case read_op: pending_ev.events |= POLLIN; break;
+        case write_op: pending_ev.events |= POLLOUT; break;
+        case except_op: pending_ev.events |= POLLPRI; break;
+        default: break;
+        }
+      }
+    }
+    interrupter_.interrupt();
+  }
+}
+
+void dev_poll_reactor::init_task()
+{
+  scheduler_.init_task();
+}
+
+int dev_poll_reactor::register_descriptor(socket_type, per_descriptor_data&)
+{
+  return 0;
+}
+
+int dev_poll_reactor::register_internal_descriptor(int op_type,
+    socket_type descriptor, per_descriptor_data&, reactor_op* op)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  op_queue_[op_type].enqueue_operation(descriptor, op);
+  ::pollfd& ev = add_pending_event_change(descriptor);
+  ev.events = POLLERR | POLLHUP;
+  switch (op_type)
+  {
+  case read_op: ev.events |= POLLIN; break;
+  case write_op: ev.events |= POLLOUT; break;
+  case except_op: ev.events |= POLLPRI; break;
+  default: break;
+  }
+  interrupter_.interrupt();
+
+  return 0;
+}
+
+void dev_poll_reactor::move_descriptor(socket_type,
+    dev_poll_reactor::per_descriptor_data&,
+    dev_poll_reactor::per_descriptor_data&)
+{
+}
+
+void dev_poll_reactor::start_op(int op_type, socket_type descriptor,
+    dev_poll_reactor::per_descriptor_data&, reactor_op* op,
+    bool is_continuation, bool allow_speculative)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  if (shutdown_)
+  {
+    post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  if (allow_speculative)
+  {
+    if (op_type != read_op || !op_queue_[except_op].has_operation(descriptor))
+    {
+      if (!op_queue_[op_type].has_operation(descriptor))
+      {
+        if (op->perform())
+        {
+          lock.unlock();
+          scheduler_.post_immediate_completion(op, is_continuation);
+          return;
+        }
+      }
+    }
+  }
+
+  bool first = op_queue_[op_type].enqueue_operation(descriptor, op);
+  scheduler_.work_started();
+  if (first)
+  {
+    ::pollfd& ev = add_pending_event_change(descriptor);
+    ev.events = POLLERR | POLLHUP;
+    if (op_type == read_op
+        || op_queue_[read_op].has_operation(descriptor))
+      ev.events |= POLLIN;
+    if (op_type == write_op
+        || op_queue_[write_op].has_operation(descriptor))
+      ev.events |= POLLOUT;
+    if (op_type == except_op
+        || op_queue_[except_op].has_operation(descriptor))
+      ev.events |= POLLPRI;
+    interrupter_.interrupt();
+  }
+}
+
+void dev_poll_reactor::cancel_ops(socket_type descriptor,
+    dev_poll_reactor::per_descriptor_data&)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  cancel_ops_unlocked(descriptor, asio::error::operation_aborted);
+}
+
+void dev_poll_reactor::deregister_descriptor(socket_type descriptor,
+    dev_poll_reactor::per_descriptor_data&, bool)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // Remove the descriptor from /dev/poll.
+  ::pollfd& ev = add_pending_event_change(descriptor);
+  ev.events = POLLREMOVE;
+  interrupter_.interrupt();
+
+  // Cancel any outstanding operations associated with the descriptor.
+  cancel_ops_unlocked(descriptor, asio::error::operation_aborted);
+}
+
+void dev_poll_reactor::deregister_internal_descriptor(
+    socket_type descriptor, dev_poll_reactor::per_descriptor_data&)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // Remove the descriptor from /dev/poll. Since this function is only called
+  // during a fork, we can apply the change immediately.
+  ::pollfd ev = { 0, 0, 0 };
+  ev.fd = descriptor;
+  ev.events = POLLREMOVE;
+  ev.revents = 0;
+  ::write(dev_poll_fd_, &ev, sizeof(ev));
+
+  // Destroy all operations associated with the descriptor.
+  op_queue<operation> ops;
+  asio::error_code ec;
+  for (int i = 0; i < max_ops; ++i)
+    op_queue_[i].cancel_operations(descriptor, ops, ec);
+}
+
+void dev_poll_reactor::cleanup_descriptor_data(
+    dev_poll_reactor::per_descriptor_data&)
+{
+}
+
+void dev_poll_reactor::run(long usec, op_queue<operation>& ops)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // We can return immediately if there's no work to do and the reactor is
+  // not supposed to block.
+  if (usec == 0 && op_queue_[read_op].empty() && op_queue_[write_op].empty()
+      && op_queue_[except_op].empty() && timer_queues_.all_empty())
+    return;
+
+  // Write the pending event registration changes to the /dev/poll descriptor.
+  std::size_t events_size = sizeof(::pollfd) * pending_event_changes_.size();
+  if (events_size > 0)
+  {
+    errno = 0;
+    int result = ::write(dev_poll_fd_,
+        &pending_event_changes_[0], events_size);
+    if (result != static_cast<int>(events_size))
+    {
+      asio::error_code ec = asio::error_code(
+          errno, asio::error::get_system_category());
+      for (std::size_t i = 0; i < pending_event_changes_.size(); ++i)
+      {
+        int descriptor = pending_event_changes_[i].fd;
+        for (int j = 0; j < max_ops; ++j)
+          op_queue_[j].cancel_operations(descriptor, ops, ec);
+      }
+    }
+    pending_event_changes_.clear();
+    pending_event_change_index_.clear();
+  }
+
+  // Calculate timeout.
+  int timeout;
+  if (usec == 0)
+    timeout = 0;
+  else
+  {
+    timeout = (usec < 0) ? -1 : ((usec - 1) / 1000 + 1);
+    timeout = get_timeout(timeout);
+  }
+  lock.unlock();
+
+  // Block on the /dev/poll descriptor.
+  ::pollfd events[128] = { { 0, 0, 0 } };
+  ::dvpoll dp = { 0, 0, 0 };
+  dp.dp_fds = events;
+  dp.dp_nfds = 128;
+  dp.dp_timeout = timeout;
+  int num_events = ::ioctl(dev_poll_fd_, DP_POLL, &dp);
+
+  lock.lock();
+
+  // Dispatch the waiting events.
+  for (int i = 0; i < num_events; ++i)
+  {
+    int descriptor = events[i].fd;
+    if (descriptor == interrupter_.read_descriptor())
+    {
+      interrupter_.reset();
+    }
+    else
+    {
+      bool more_reads = false;
+      bool more_writes = false;
+      bool more_except = false;
+
+      // Exception operations must be processed first to ensure that any
+      // out-of-band data is read before normal data.
+      if (events[i].events & (POLLPRI | POLLERR | POLLHUP))
+        more_except =
+          op_queue_[except_op].perform_operations(descriptor, ops);
+      else
+        more_except = op_queue_[except_op].has_operation(descriptor);
+
+      if (events[i].events & (POLLIN | POLLERR | POLLHUP))
+        more_reads = op_queue_[read_op].perform_operations(descriptor, ops);
+      else
+        more_reads = op_queue_[read_op].has_operation(descriptor);
+
+      if (events[i].events & (POLLOUT | POLLERR | POLLHUP))
+        more_writes = op_queue_[write_op].perform_operations(descriptor, ops);
+      else
+        more_writes = op_queue_[write_op].has_operation(descriptor);
+
+      if ((events[i].events & (POLLERR | POLLHUP)) != 0
+            && !more_except && !more_reads && !more_writes)
+      {
+        // If we have an event and no operations associated with the
+        // descriptor then we need to delete the descriptor from /dev/poll.
+        // The poll operation can produce POLLHUP or POLLERR events when there
+        // is no operation pending, so if we do not remove the descriptor we
+        // can end up in a tight polling loop.
+        ::pollfd ev = { 0, 0, 0 };
+        ev.fd = descriptor;
+        ev.events = POLLREMOVE;
+        ev.revents = 0;
+        ::write(dev_poll_fd_, &ev, sizeof(ev));
+      }
+      else
+      {
+        ::pollfd ev = { 0, 0, 0 };
+        ev.fd = descriptor;
+        ev.events = POLLERR | POLLHUP;
+        if (more_reads)
+          ev.events |= POLLIN;
+        if (more_writes)
+          ev.events |= POLLOUT;
+        if (more_except)
+          ev.events |= POLLPRI;
+        ev.revents = 0;
+        int result = ::write(dev_poll_fd_, &ev, sizeof(ev));
+        if (result != sizeof(ev))
+        {
+          asio::error_code ec(errno,
+              asio::error::get_system_category());
+          for (int j = 0; j < max_ops; ++j)
+            op_queue_[j].cancel_operations(descriptor, ops, ec);
+        }
+      }
+    }
+  }
+  timer_queues_.get_ready_timers(ops);
+}
+
+void dev_poll_reactor::interrupt()
+{
+  interrupter_.interrupt();
+}
+
+int dev_poll_reactor::do_dev_poll_create()
+{
+  int fd = ::open("/dev/poll", O_RDWR);
+  if (fd == -1)
+  {
+    asio::error_code ec(errno,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "/dev/poll");
+  }
+  return fd;
+}
+
+void dev_poll_reactor::do_add_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.insert(&queue);
+}
+
+void dev_poll_reactor::do_remove_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.erase(&queue);
+}
+
+int dev_poll_reactor::get_timeout(int msec)
+{
+  // By default we will wait no longer than 5 minutes. This will ensure that
+  // any changes to the system clock are detected after no longer than this.
+  const int max_msec = 5 * 60 * 1000;
+  return timer_queues_.wait_duration_msec(
+      (msec < 0 || max_msec < msec) ? max_msec : msec);
+}
+
+void dev_poll_reactor::cancel_ops_unlocked(socket_type descriptor,
+    const asio::error_code& ec)
+{
+  bool need_interrupt = false;
+  op_queue<operation> ops;
+  for (int i = 0; i < max_ops; ++i)
+    need_interrupt = op_queue_[i].cancel_operations(
+        descriptor, ops, ec) || need_interrupt;
+  scheduler_.post_deferred_completions(ops);
+  if (need_interrupt)
+    interrupter_.interrupt();
+}
+
+::pollfd& dev_poll_reactor::add_pending_event_change(int descriptor)
+{
+  hash_map<int, std::size_t>::iterator iter
+    = pending_event_change_index_.find(descriptor);
+  if (iter == pending_event_change_index_.end())
+  {
+    std::size_t index = pending_event_changes_.size();
+    pending_event_changes_.reserve(pending_event_changes_.size() + 1);
+    pending_event_change_index_.insert(std::make_pair(descriptor, index));
+    pending_event_changes_.push_back(::pollfd());
+    pending_event_changes_[index].fd = descriptor;
+    pending_event_changes_[index].revents = 0;
+    return pending_event_changes_[index];
+  }
+  else
+  {
+    return pending_event_changes_[iter->second];
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_DEV_POLL)
+
+#endif // ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/epoll_reactor.hpp b/subprojects/asio/include/asio/detail/impl/epoll_reactor.hpp
new file mode 100644
index 000000000..f990059d8
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/epoll_reactor.hpp
@@ -0,0 +1,89 @@
+//
+// detail/impl/epoll_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_EPOLL_REACTOR_HPP
+#define ASIO_DETAIL_IMPL_EPOLL_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if defined(ASIO_HAS_EPOLL)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+void epoll_reactor::add_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_add_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void epoll_reactor::remove_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_remove_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void epoll_reactor::schedule_timer(timer_queue<Time_Traits>& queue,
+    const typename Time_Traits::time_type& time,
+    typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op)
+{
+  mutex::scoped_lock lock(mutex_);
+
+  if (shutdown_)
+  {
+    scheduler_.post_immediate_completion(op, false);
+    return;
+  }
+
+  bool earliest = queue.enqueue_timer(time, timer, op);
+  scheduler_.work_started();
+  if (earliest)
+    update_timeout();
+}
+
+template <typename Time_Traits>
+std::size_t epoll_reactor::cancel_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& timer,
+    std::size_t max_cancelled)
+{
+  mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  std::size_t n = queue.cancel_timer(timer, ops, max_cancelled);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+  return n;
+}
+
+template <typename Time_Traits>
+void epoll_reactor::move_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& target,
+    typename timer_queue<Time_Traits>::per_timer_data& source)
+{
+  mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  queue.cancel_timer(target, ops);
+  queue.move_timer(target, source);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_EPOLL)
+
+#endif // ASIO_DETAIL_IMPL_EPOLL_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/epoll_reactor.ipp b/subprojects/asio/include/asio/detail/impl/epoll_reactor.ipp
new file mode 100644
index 000000000..65584a434
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/epoll_reactor.ipp
@@ -0,0 +1,787 @@
+//
+// detail/impl/epoll_reactor.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_EPOLL_REACTOR_IPP
+#define ASIO_DETAIL_IMPL_EPOLL_REACTOR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_EPOLL)
+
+#include <cstddef>
+#include <sys/epoll.h>
+#include "asio/detail/epoll_reactor.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#if defined(ASIO_HAS_TIMERFD)
+# include <sys/timerfd.h>
+#endif // defined(ASIO_HAS_TIMERFD)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+epoll_reactor::epoll_reactor(asio::execution_context& ctx)
+  : execution_context_service_base<epoll_reactor>(ctx),
+    scheduler_(use_service<scheduler>(ctx)),
+    mutex_(ASIO_CONCURRENCY_HINT_IS_LOCKING(
+          REACTOR_REGISTRATION, scheduler_.concurrency_hint())),
+    interrupter_(),
+    epoll_fd_(do_epoll_create()),
+    timer_fd_(do_timerfd_create()),
+    shutdown_(false),
+    registered_descriptors_mutex_(mutex_.enabled())
+{
+  // Add the interrupter's descriptor to epoll.
+  epoll_event ev = { 0, { 0 } };
+  ev.events = EPOLLIN | EPOLLERR | EPOLLET;
+  ev.data.ptr = &interrupter_;
+  epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, interrupter_.read_descriptor(), &ev);
+  interrupter_.interrupt();
+
+  // Add the timer descriptor to epoll.
+  if (timer_fd_ != -1)
+  {
+    ev.events = EPOLLIN | EPOLLERR;
+    ev.data.ptr = &timer_fd_;
+    epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &ev);
+  }
+}
+
+epoll_reactor::~epoll_reactor()
+{
+  if (epoll_fd_ != -1)
+    close(epoll_fd_);
+  if (timer_fd_ != -1)
+    close(timer_fd_);
+}
+
+void epoll_reactor::shutdown()
+{
+  mutex::scoped_lock lock(mutex_);
+  shutdown_ = true;
+  lock.unlock();
+
+  op_queue<operation> ops;
+
+  while (descriptor_state* state = registered_descriptors_.first())
+  {
+    for (int i = 0; i < max_ops; ++i)
+      ops.push(state->op_queue_[i]);
+    state->shutdown_ = true;
+    registered_descriptors_.free(state);
+  }
+
+  timer_queues_.get_all_timers(ops);
+
+  scheduler_.abandon_operations(ops);
+}
+
+void epoll_reactor::notify_fork(
+    asio::execution_context::fork_event fork_ev)
+{
+  if (fork_ev == asio::execution_context::fork_child)
+  {
+    if (epoll_fd_ != -1)
+      ::close(epoll_fd_);
+    epoll_fd_ = -1;
+    epoll_fd_ = do_epoll_create();
+
+    if (timer_fd_ != -1)
+      ::close(timer_fd_);
+    timer_fd_ = -1;
+    timer_fd_ = do_timerfd_create();
+
+    interrupter_.recreate();
+
+    // Add the interrupter's descriptor to epoll.
+    epoll_event ev = { 0, { 0 } };
+    ev.events = EPOLLIN | EPOLLERR | EPOLLET;
+    ev.data.ptr = &interrupter_;
+    epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, interrupter_.read_descriptor(), &ev);
+    interrupter_.interrupt();
+
+    // Add the timer descriptor to epoll.
+    if (timer_fd_ != -1)
+    {
+      ev.events = EPOLLIN | EPOLLERR;
+      ev.data.ptr = &timer_fd_;
+      epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &ev);
+    }
+
+    update_timeout();
+
+    // Re-register all descriptors with epoll.
+    mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
+    for (descriptor_state* state = registered_descriptors_.first();
+        state != 0; state = state->next_)
+    {
+      ev.events = state->registered_events_;
+      ev.data.ptr = state;
+      int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, state->descriptor_, &ev);
+      if (result != 0)
+      {
+        asio::error_code ec(errno,
+            asio::error::get_system_category());
+        asio::detail::throw_error(ec, "epoll re-registration");
+      }
+    }
+  }
+}
+
+void epoll_reactor::init_task()
+{
+  scheduler_.init_task();
+}
+
+int epoll_reactor::register_descriptor(socket_type descriptor,
+    epoll_reactor::per_descriptor_data& descriptor_data)
+{
+  descriptor_data = allocate_descriptor_state();
+
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
+  {
+    mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+    descriptor_data->reactor_ = this;
+    descriptor_data->descriptor_ = descriptor;
+    descriptor_data->shutdown_ = false;
+    for (int i = 0; i < max_ops; ++i)
+      descriptor_data->try_speculative_[i] = true;
+  }
+
+  epoll_event ev = { 0, { 0 } };
+  ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLPRI | EPOLLET;
+  descriptor_data->registered_events_ = ev.events;
+  ev.data.ptr = descriptor_data;
+  int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, descriptor, &ev);
+  if (result != 0)
+  {
+    if (errno == EPERM)
+    {
+      // This file descriptor type is not supported by epoll. However, if it is
+      // a regular file then operations on it will not block. We will allow
+      // this descriptor to be used and fail later if an operation on it would
+      // otherwise require a trip through the reactor.
+      descriptor_data->registered_events_ = 0;
+      return 0;
+    }
+    return errno;
+  }
+
+  return 0;
+}
+
+int epoll_reactor::register_internal_descriptor(
+    int op_type, socket_type descriptor,
+    epoll_reactor::per_descriptor_data& descriptor_data, reactor_op* op)
+{
+  descriptor_data = allocate_descriptor_state();
+
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
+  {
+    mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+    descriptor_data->reactor_ = this;
+    descriptor_data->descriptor_ = descriptor;
+    descriptor_data->shutdown_ = false;
+    descriptor_data->op_queue_[op_type].push(op);
+    for (int i = 0; i < max_ops; ++i)
+      descriptor_data->try_speculative_[i] = true;
+  }
+
+  epoll_event ev = { 0, { 0 } };
+  ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLPRI | EPOLLET;
+  descriptor_data->registered_events_ = ev.events;
+  ev.data.ptr = descriptor_data;
+  int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, descriptor, &ev);
+  if (result != 0)
+    return errno;
+
+  return 0;
+}
+
+void epoll_reactor::move_descriptor(socket_type,
+    epoll_reactor::per_descriptor_data& target_descriptor_data,
+    epoll_reactor::per_descriptor_data& source_descriptor_data)
+{
+  target_descriptor_data = source_descriptor_data;
+  source_descriptor_data = 0;
+}
+
+void epoll_reactor::start_op(int op_type, socket_type descriptor,
+    epoll_reactor::per_descriptor_data& descriptor_data, reactor_op* op,
+    bool is_continuation, bool allow_speculative)
+{
+  if (!descriptor_data)
+  {
+    op->ec_ = asio::error::bad_descriptor;
+    post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  if (descriptor_data->shutdown_)
+  {
+    post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  if (descriptor_data->op_queue_[op_type].empty())
+  {
+    if (allow_speculative
+        && (op_type != read_op
+          || descriptor_data->op_queue_[except_op].empty()))
+    {
+      if (descriptor_data->try_speculative_[op_type])
+      {
+        if (reactor_op::status status = op->perform())
+        {
+          if (status == reactor_op::done_and_exhausted)
+            if (descriptor_data->registered_events_ != 0)
+              descriptor_data->try_speculative_[op_type] = false;
+          descriptor_lock.unlock();
+          scheduler_.post_immediate_completion(op, is_continuation);
+          return;
+        }
+      }
+
+      if (descriptor_data->registered_events_ == 0)
+      {
+        op->ec_ = asio::error::operation_not_supported;
+        scheduler_.post_immediate_completion(op, is_continuation);
+        return;
+      }
+
+      if (op_type == write_op)
+      {
+        if ((descriptor_data->registered_events_ & EPOLLOUT) == 0)
+        {
+          epoll_event ev = { 0, { 0 } };
+          ev.events = descriptor_data->registered_events_ | EPOLLOUT;
+          ev.data.ptr = descriptor_data;
+          if (epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, descriptor, &ev) == 0)
+          {
+            descriptor_data->registered_events_ |= ev.events;
+          }
+          else
+          {
+            op->ec_ = asio::error_code(errno,
+                asio::error::get_system_category());
+            scheduler_.post_immediate_completion(op, is_continuation);
+            return;
+          }
+        }
+      }
+    }
+    else if (descriptor_data->registered_events_ == 0)
+    {
+      op->ec_ = asio::error::operation_not_supported;
+      scheduler_.post_immediate_completion(op, is_continuation);
+      return;
+    }
+    else
+    {
+      if (op_type == write_op)
+      {
+        descriptor_data->registered_events_ |= EPOLLOUT;
+      }
+
+      epoll_event ev = { 0, { 0 } };
+      ev.events = descriptor_data->registered_events_;
+      ev.data.ptr = descriptor_data;
+      epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, descriptor, &ev);
+    }
+  }
+
+  descriptor_data->op_queue_[op_type].push(op);
+  scheduler_.work_started();
+}
+
+void epoll_reactor::cancel_ops(socket_type,
+    epoll_reactor::per_descriptor_data& descriptor_data)
+{
+  if (!descriptor_data)
+    return;
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  op_queue<operation> ops;
+  for (int i = 0; i < max_ops; ++i)
+  {
+    while (reactor_op* op = descriptor_data->op_queue_[i].front())
+    {
+      op->ec_ = asio::error::operation_aborted;
+      descriptor_data->op_queue_[i].pop();
+      ops.push(op);
+    }
+  }
+
+  descriptor_lock.unlock();
+
+  scheduler_.post_deferred_completions(ops);
+}
+
+void epoll_reactor::deregister_descriptor(socket_type descriptor,
+    epoll_reactor::per_descriptor_data& descriptor_data, bool closing)
+{
+  if (!descriptor_data)
+    return;
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  if (!descriptor_data->shutdown_)
+  {
+    if (closing)
+    {
+      // The descriptor will be automatically removed from the epoll set when
+      // it is closed.
+    }
+    else if (descriptor_data->registered_events_ != 0)
+    {
+      epoll_event ev = { 0, { 0 } };
+      epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, descriptor, &ev);
+    }
+
+    op_queue<operation> ops;
+    for (int i = 0; i < max_ops; ++i)
+    {
+      while (reactor_op* op = descriptor_data->op_queue_[i].front())
+      {
+        op->ec_ = asio::error::operation_aborted;
+        descriptor_data->op_queue_[i].pop();
+        ops.push(op);
+      }
+    }
+
+    descriptor_data->descriptor_ = -1;
+    descriptor_data->shutdown_ = true;
+
+    descriptor_lock.unlock();
+
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
+    scheduler_.post_deferred_completions(ops);
+
+    // Leave descriptor_data set so that it will be freed by the subsequent
+    // call to cleanup_descriptor_data.
+  }
+  else
+  {
+    // We are shutting down, so prevent cleanup_descriptor_data from freeing
+    // the descriptor_data object and let the destructor free it instead.
+    descriptor_data = 0;
+  }
+}
+
+void epoll_reactor::deregister_internal_descriptor(socket_type descriptor,
+    epoll_reactor::per_descriptor_data& descriptor_data)
+{
+  if (!descriptor_data)
+    return;
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  if (!descriptor_data->shutdown_)
+  {
+    epoll_event ev = { 0, { 0 } };
+    epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, descriptor, &ev);
+
+    op_queue<operation> ops;
+    for (int i = 0; i < max_ops; ++i)
+      ops.push(descriptor_data->op_queue_[i]);
+
+    descriptor_data->descriptor_ = -1;
+    descriptor_data->shutdown_ = true;
+
+    descriptor_lock.unlock();
+
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
+    // Leave descriptor_data set so that it will be freed by the subsequent
+    // call to cleanup_descriptor_data.
+  }
+  else
+  {
+    // We are shutting down, so prevent cleanup_descriptor_data from freeing
+    // the descriptor_data object and let the destructor free it instead.
+    descriptor_data = 0;
+  }
+}
+
+void epoll_reactor::cleanup_descriptor_data(
+    per_descriptor_data& descriptor_data)
+{
+  if (descriptor_data)
+  {
+    free_descriptor_state(descriptor_data);
+    descriptor_data = 0;
+  }
+}
+
+void epoll_reactor::run(long usec, op_queue<operation>& ops)
+{
+  // This code relies on the fact that the scheduler queues the reactor task
+  // behind all descriptor operations generated by this function. This means,
+  // that by the time we reach this point, any previously returned descriptor
+  // operations have already been dequeued. Therefore it is now safe for us to
+  // reuse and return them for the scheduler to queue again.
+
+  // Calculate timeout. Check the timer queues only if timerfd is not in use.
+  int timeout;
+  if (usec == 0)
+    timeout = 0;
+  else
+  {
+    timeout = (usec < 0) ? -1 : ((usec - 1) / 1000 + 1);
+    if (timer_fd_ == -1)
+    {
+      mutex::scoped_lock lock(mutex_);
+      timeout = get_timeout(timeout);
+    }
+  }
+
+  // Block on the epoll descriptor.
+  epoll_event events[128];
+  int num_events = epoll_wait(epoll_fd_, events, 128, timeout);
+
+#if defined(ASIO_ENABLE_HANDLER_TRACKING)
+  // Trace the waiting events.
+  for (int i = 0; i < num_events; ++i)
+  {
+    void* ptr = events[i].data.ptr;
+    if (ptr == &interrupter_)
+    {
+      // Ignore.
+    }
+# if defined(ASIO_HAS_TIMERFD)
+    else if (ptr == &timer_fd_)
+    {
+      // Ignore.
+    }
+# endif // defined(ASIO_HAS_TIMERFD)
+    else
+    {
+      unsigned event_mask = 0;
+      if ((events[i].events & EPOLLIN) != 0)
+        event_mask |= ASIO_HANDLER_REACTOR_READ_EVENT;
+      if ((events[i].events & EPOLLOUT))
+        event_mask |= ASIO_HANDLER_REACTOR_WRITE_EVENT;
+      if ((events[i].events & (EPOLLERR | EPOLLHUP)) != 0)
+        event_mask |= ASIO_HANDLER_REACTOR_ERROR_EVENT;
+      ASIO_HANDLER_REACTOR_EVENTS((context(),
+            reinterpret_cast<uintmax_t>(ptr), event_mask));
+    }
+  }
+#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+#if defined(ASIO_HAS_TIMERFD)
+  bool check_timers = (timer_fd_ == -1);
+#else // defined(ASIO_HAS_TIMERFD)
+  bool check_timers = true;
+#endif // defined(ASIO_HAS_TIMERFD)
+
+  // Dispatch the waiting events.
+  for (int i = 0; i < num_events; ++i)
+  {
+    void* ptr = events[i].data.ptr;
+    if (ptr == &interrupter_)
+    {
+      // No need to reset the interrupter since we're leaving the descriptor
+      // in a ready-to-read state and relying on edge-triggered notifications
+      // to make it so that we only get woken up when the descriptor's epoll
+      // registration is updated.
+
+#if defined(ASIO_HAS_TIMERFD)
+      if (timer_fd_ == -1)
+        check_timers = true;
+#else // defined(ASIO_HAS_TIMERFD)
+      check_timers = true;
+#endif // defined(ASIO_HAS_TIMERFD)
+    }
+#if defined(ASIO_HAS_TIMERFD)
+    else if (ptr == &timer_fd_)
+    {
+      check_timers = true;
+    }
+#endif // defined(ASIO_HAS_TIMERFD)
+    else
+    {
+      // The descriptor operation doesn't count as work in and of itself, so we
+      // don't call work_started() here. This still allows the scheduler to
+      // stop if the only remaining operations are descriptor operations.
+      descriptor_state* descriptor_data = static_cast<descriptor_state*>(ptr);
+      if (!ops.is_enqueued(descriptor_data))
+      {
+        descriptor_data->set_ready_events(events[i].events);
+        ops.push(descriptor_data);
+      }
+      else
+      {
+        descriptor_data->add_ready_events(events[i].events);
+      }
+    }
+  }
+
+  if (check_timers)
+  {
+    mutex::scoped_lock common_lock(mutex_);
+    timer_queues_.get_ready_timers(ops);
+
+#if defined(ASIO_HAS_TIMERFD)
+    if (timer_fd_ != -1)
+    {
+      itimerspec new_timeout;
+      itimerspec old_timeout;
+      int flags = get_timeout(new_timeout);
+      timerfd_settime(timer_fd_, flags, &new_timeout, &old_timeout);
+    }
+#endif // defined(ASIO_HAS_TIMERFD)
+  }
+}
+
+void epoll_reactor::interrupt()
+{
+  epoll_event ev = { 0, { 0 } };
+  ev.events = EPOLLIN | EPOLLERR | EPOLLET;
+  ev.data.ptr = &interrupter_;
+  epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, interrupter_.read_descriptor(), &ev);
+}
+
+int epoll_reactor::do_epoll_create()
+{
+#if defined(EPOLL_CLOEXEC)
+  int fd = epoll_create1(EPOLL_CLOEXEC);
+#else // defined(EPOLL_CLOEXEC)
+  int fd = -1;
+  errno = EINVAL;
+#endif // defined(EPOLL_CLOEXEC)
+
+  if (fd == -1 && (errno == EINVAL || errno == ENOSYS))
+  {
+    fd = epoll_create(epoll_size);
+    if (fd != -1)
+      ::fcntl(fd, F_SETFD, FD_CLOEXEC);
+  }
+
+  if (fd == -1)
+  {
+    asio::error_code ec(errno,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "epoll");
+  }
+
+  return fd;
+}
+
+int epoll_reactor::do_timerfd_create()
+{
+#if defined(ASIO_HAS_TIMERFD)
+# if defined(TFD_CLOEXEC)
+  int fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
+# else // defined(TFD_CLOEXEC)
+  int fd = -1;
+  errno = EINVAL;
+# endif // defined(TFD_CLOEXEC)
+
+  if (fd == -1 && errno == EINVAL)
+  {
+    fd = timerfd_create(CLOCK_MONOTONIC, 0);
+    if (fd != -1)
+      ::fcntl(fd, F_SETFD, FD_CLOEXEC);
+  }
+
+  return fd;
+#else // defined(ASIO_HAS_TIMERFD)
+  return -1;
+#endif // defined(ASIO_HAS_TIMERFD)
+}
+
+epoll_reactor::descriptor_state* epoll_reactor::allocate_descriptor_state()
+{
+  mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
+  return registered_descriptors_.alloc(ASIO_CONCURRENCY_HINT_IS_LOCKING(
+        REACTOR_IO, scheduler_.concurrency_hint()));
+}
+
+void epoll_reactor::free_descriptor_state(epoll_reactor::descriptor_state* s)
+{
+  mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
+  registered_descriptors_.free(s);
+}
+
+void epoll_reactor::do_add_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.insert(&queue);
+}
+
+void epoll_reactor::do_remove_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.erase(&queue);
+}
+
+void epoll_reactor::update_timeout()
+{
+#if defined(ASIO_HAS_TIMERFD)
+  if (timer_fd_ != -1)
+  {
+    itimerspec new_timeout;
+    itimerspec old_timeout;
+    int flags = get_timeout(new_timeout);
+    timerfd_settime(timer_fd_, flags, &new_timeout, &old_timeout);
+    return;
+  }
+#endif // defined(ASIO_HAS_TIMERFD)
+  interrupt();
+}
+
+int epoll_reactor::get_timeout(int msec)
+{
+  // By default we will wait no longer than 5 minutes. This will ensure that
+  // any changes to the system clock are detected after no longer than this.
+  const int max_msec = 5 * 60 * 1000;
+  return timer_queues_.wait_duration_msec(
+      (msec < 0 || max_msec < msec) ? max_msec : msec);
+}
+
+#if defined(ASIO_HAS_TIMERFD)
+int epoll_reactor::get_timeout(itimerspec& ts)
+{
+  ts.it_interval.tv_sec = 0;
+  ts.it_interval.tv_nsec = 0;
+
+  long usec = timer_queues_.wait_duration_usec(5 * 60 * 1000 * 1000);
+  ts.it_value.tv_sec = usec / 1000000;
+  ts.it_value.tv_nsec = usec ? (usec % 1000000) * 1000 : 1;
+
+  return usec ? 0 : TFD_TIMER_ABSTIME;
+}
+#endif // defined(ASIO_HAS_TIMERFD)
+
+struct epoll_reactor::perform_io_cleanup_on_block_exit
+{
+  explicit perform_io_cleanup_on_block_exit(epoll_reactor* r)
+    : reactor_(r), first_op_(0)
+  {
+  }
+
+  ~perform_io_cleanup_on_block_exit()
+  {
+    if (first_op_)
+    {
+      // Post the remaining completed operations for invocation.
+      if (!ops_.empty())
+        reactor_->scheduler_.post_deferred_completions(ops_);
+
+      // A user-initiated operation has completed, but there's no need to
+      // explicitly call work_finished() here. Instead, we'll take advantage of
+      // the fact that the scheduler will call work_finished() once we return.
+    }
+    else
+    {
+      // No user-initiated operations have completed, so we need to compensate
+      // for the work_finished() call that the scheduler will make once this
+      // operation returns.
+      reactor_->scheduler_.compensating_work_started();
+    }
+  }
+
+  epoll_reactor* reactor_;
+  op_queue<operation> ops_;
+  operation* first_op_;
+};
+
+epoll_reactor::descriptor_state::descriptor_state(bool locking)
+  : operation(&epoll_reactor::descriptor_state::do_complete),
+    mutex_(locking)
+{
+}
+
+operation* epoll_reactor::descriptor_state::perform_io(uint32_t events)
+{
+  mutex_.lock();
+  perform_io_cleanup_on_block_exit io_cleanup(reactor_);
+  mutex::scoped_lock descriptor_lock(mutex_, mutex::scoped_lock::adopt_lock);
+
+  // Exception operations must be processed first to ensure that any
+  // out-of-band data is read before normal data.
+  static const int flag[max_ops] = { EPOLLIN, EPOLLOUT, EPOLLPRI };
+  for (int j = max_ops - 1; j >= 0; --j)
+  {
+    if (events & (flag[j] | EPOLLERR | EPOLLHUP))
+    {
+      try_speculative_[j] = true;
+      while (reactor_op* op = op_queue_[j].front())
+      {
+        if (reactor_op::status status = op->perform())
+        {
+          op_queue_[j].pop();
+          io_cleanup.ops_.push(op);
+          if (status == reactor_op::done_and_exhausted)
+          {
+            try_speculative_[j] = false;
+            break;
+          }
+        }
+        else
+          break;
+      }
+    }
+  }
+
+  // The first operation will be returned for completion now. The others will
+  // be posted for later by the io_cleanup object's destructor.
+  io_cleanup.first_op_ = io_cleanup.ops_.front();
+  io_cleanup.ops_.pop();
+  return io_cleanup.first_op_;
+}
+
+void epoll_reactor::descriptor_state::do_complete(
+    void* owner, operation* base,
+    const asio::error_code& ec, std::size_t bytes_transferred)
+{
+  if (owner)
+  {
+    descriptor_state* descriptor_data = static_cast<descriptor_state*>(base);
+    uint32_t events = static_cast<uint32_t>(bytes_transferred);
+    if (operation* op = descriptor_data->perform_io(events))
+    {
+      op->complete(owner, ec, 0);
+    }
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_EPOLL)
+
+#endif // ASIO_DETAIL_IMPL_EPOLL_REACTOR_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/eventfd_select_interrupter.ipp b/subprojects/asio/include/asio/detail/impl/eventfd_select_interrupter.ipp
new file mode 100644
index 000000000..c56e89ad2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/eventfd_select_interrupter.ipp
@@ -0,0 +1,165 @@
+//
+// detail/impl/eventfd_select_interrupter.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Roelof Naude (roelof.naude at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_IPP
+#define ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_EVENTFD)
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+# include <asm/unistd.h>
+#else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+# include <sys/eventfd.h>
+#endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+#include "asio/detail/cstdint.hpp"
+#include "asio/detail/eventfd_select_interrupter.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+eventfd_select_interrupter::eventfd_select_interrupter()
+{
+  open_descriptors();
+}
+
+void eventfd_select_interrupter::open_descriptors()
+{
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+  write_descriptor_ = read_descriptor_ = syscall(__NR_eventfd, 0);
+  if (read_descriptor_ != -1)
+  {
+    ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
+    ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
+  }
+#else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+# if defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
+  write_descriptor_ = read_descriptor_ =
+    ::eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
+# else // defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
+  errno = EINVAL;
+  write_descriptor_ = read_descriptor_ = -1;
+# endif // defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
+  if (read_descriptor_ == -1 && errno == EINVAL)
+  {
+    write_descriptor_ = read_descriptor_ = ::eventfd(0, 0);
+    if (read_descriptor_ != -1)
+    {
+      ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
+      ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
+    }
+  }
+#endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+
+  if (read_descriptor_ == -1)
+  {
+    int pipe_fds[2];
+    if (pipe(pipe_fds) == 0)
+    {
+      read_descriptor_ = pipe_fds[0];
+      ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
+      ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
+      write_descriptor_ = pipe_fds[1];
+      ::fcntl(write_descriptor_, F_SETFL, O_NONBLOCK);
+      ::fcntl(write_descriptor_, F_SETFD, FD_CLOEXEC);
+    }
+    else
+    {
+      asio::error_code ec(errno,
+          asio::error::get_system_category());
+      asio::detail::throw_error(ec, "eventfd_select_interrupter");
+    }
+  }
+}
+
+eventfd_select_interrupter::~eventfd_select_interrupter()
+{
+  close_descriptors();
+}
+
+void eventfd_select_interrupter::close_descriptors()
+{
+  if (write_descriptor_ != -1 && write_descriptor_ != read_descriptor_)
+    ::close(write_descriptor_);
+  if (read_descriptor_ != -1)
+    ::close(read_descriptor_);
+}
+
+void eventfd_select_interrupter::recreate()
+{
+  close_descriptors();
+
+  write_descriptor_ = -1;
+  read_descriptor_ = -1;
+
+  open_descriptors();
+}
+
+void eventfd_select_interrupter::interrupt()
+{
+  uint64_t counter(1UL);
+  int result = ::write(write_descriptor_, &counter, sizeof(uint64_t));
+  (void)result;
+}
+
+bool eventfd_select_interrupter::reset()
+{
+  if (write_descriptor_ == read_descriptor_)
+  {
+    for (;;)
+    {
+      // Only perform one read. The kernel maintains an atomic counter.
+      uint64_t counter(0);
+      errno = 0;
+      int bytes_read = ::read(read_descriptor_, &counter, sizeof(uint64_t));
+      if (bytes_read < 0 && errno == EINTR)
+        continue;
+      bool was_interrupted = (bytes_read > 0);
+      return was_interrupted;
+    }
+  }
+  else
+  {
+    for (;;)
+    {
+      // Clear all data from the pipe.
+      char data[1024];
+      int bytes_read = ::read(read_descriptor_, data, sizeof(data));
+      if (bytes_read < 0 && errno == EINTR)
+        continue;
+      bool was_interrupted = (bytes_read > 0);
+      while (bytes_read == sizeof(data))
+        bytes_read = ::read(read_descriptor_, data, sizeof(data));
+      return was_interrupted;
+    }
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_EVENTFD)
+
+#endif // ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/handler_tracking.ipp b/subprojects/asio/include/asio/detail/impl/handler_tracking.ipp
new file mode 100644
index 000000000..5a4ff6f0f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/handler_tracking.ipp
@@ -0,0 +1,358 @@
+//
+// detail/impl/handler_tracking.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_HANDLER_TRACKING_IPP
+#define ASIO_DETAIL_IMPL_HANDLER_TRACKING_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_CUSTOM_HANDLER_TRACKING)
+
+// The handler tracking implementation is provided by the user-specified header.
+
+#elif defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+#include <cstdarg>
+#include <cstdio>
+#include "asio/detail/handler_tracking.hpp"
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+# include "asio/time_traits.hpp"
+#elif defined(ASIO_HAS_CHRONO)
+# include "asio/detail/chrono.hpp"
+# include "asio/detail/chrono_time_traits.hpp"
+# include "asio/wait_traits.hpp"
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/socket_types.hpp"
+#elif !defined(ASIO_WINDOWS)
+# include <unistd.h>
+#endif // !defined(ASIO_WINDOWS)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct handler_tracking_timestamp
+{
+  uint64_t seconds;
+  uint64_t microseconds;
+
+  handler_tracking_timestamp()
+  {
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+    boost::posix_time::ptime epoch(boost::gregorian::date(1970, 1, 1));
+    boost::posix_time::time_duration now =
+      boost::posix_time::microsec_clock::universal_time() - epoch;
+#elif defined(ASIO_HAS_CHRONO)
+    typedef chrono_time_traits<chrono::system_clock,
+        asio::wait_traits<chrono::system_clock> > traits_helper;
+    traits_helper::posix_time_duration now(
+        chrono::system_clock::now().time_since_epoch());
+#endif
+    seconds = static_cast<uint64_t>(now.total_seconds());
+    microseconds = static_cast<uint64_t>(now.total_microseconds() % 1000000);
+  }
+};
+
+struct handler_tracking::tracking_state
+{
+  static_mutex mutex_;
+  uint64_t next_id_;
+  tss_ptr<completion>* current_completion_;
+};
+
+handler_tracking::tracking_state* handler_tracking::get_state()
+{
+  static tracking_state state = { ASIO_STATIC_MUTEX_INIT, 1, 0 };
+  return &state;
+}
+
+void handler_tracking::init()
+{
+  static tracking_state* state = get_state();
+
+  state->mutex_.init();
+
+  static_mutex::scoped_lock lock(state->mutex_);
+  if (state->current_completion_ == 0)
+    state->current_completion_ = new tss_ptr<completion>;
+}
+
+void handler_tracking::creation(execution_context&,
+    handler_tracking::tracked_handler& h,
+    const char* object_type, void* object,
+    uintmax_t /*native_handle*/, const char* op_name)
+{
+  static tracking_state* state = get_state();
+
+  static_mutex::scoped_lock lock(state->mutex_);
+  h.id_ = state->next_id_++;
+  lock.unlock();
+
+  handler_tracking_timestamp timestamp;
+
+  uint64_t current_id = 0;
+  if (completion* current_completion = *state->current_completion_)
+    current_id = current_completion->id_;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|%I64u*%I64u|%.20s@%p.%.50s\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|%llu*%llu|%.20s@%p.%.50s\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      current_id, h.id_, object_type, object, op_name);
+}
+
+handler_tracking::completion::completion(
+    const handler_tracking::tracked_handler& h)
+  : id_(h.id_),
+    invoked_(false),
+    next_(*get_state()->current_completion_)
+{
+  *get_state()->current_completion_ = this;
+}
+
+handler_tracking::completion::~completion()
+{
+  if (id_)
+  {
+    handler_tracking_timestamp timestamp;
+
+    write_line(
+#if defined(ASIO_WINDOWS)
+        "@asio|%I64u.%06I64u|%c%I64u|\n",
+#else // defined(ASIO_WINDOWS)
+        "@asio|%llu.%06llu|%c%llu|\n",
+#endif // defined(ASIO_WINDOWS)
+        timestamp.seconds, timestamp.microseconds,
+        invoked_ ? '!' : '~', id_);
+  }
+
+  *get_state()->current_completion_ = next_;
+}
+
+void handler_tracking::completion::invocation_begin()
+{
+  handler_tracking_timestamp timestamp;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|>%I64u|\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|>%llu|\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds, id_);
+
+  invoked_ = true;
+}
+
+void handler_tracking::completion::invocation_begin(
+    const asio::error_code& ec)
+{
+  handler_tracking_timestamp timestamp;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|>%I64u|ec=%.20s:%d\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|>%llu|ec=%.20s:%d\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      id_, ec.category().name(), ec.value());
+
+  invoked_ = true;
+}
+
+void handler_tracking::completion::invocation_begin(
+    const asio::error_code& ec, std::size_t bytes_transferred)
+{
+  handler_tracking_timestamp timestamp;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|>%I64u|ec=%.20s:%d,bytes_transferred=%I64u\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|>%llu|ec=%.20s:%d,bytes_transferred=%llu\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      id_, ec.category().name(), ec.value(),
+      static_cast<uint64_t>(bytes_transferred));
+
+  invoked_ = true;
+}
+
+void handler_tracking::completion::invocation_begin(
+    const asio::error_code& ec, int signal_number)
+{
+  handler_tracking_timestamp timestamp;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|>%I64u|ec=%.20s:%d,signal_number=%d\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|>%llu|ec=%.20s:%d,signal_number=%d\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      id_, ec.category().name(), ec.value(), signal_number);
+
+  invoked_ = true;
+}
+
+void handler_tracking::completion::invocation_begin(
+    const asio::error_code& ec, const char* arg)
+{
+  handler_tracking_timestamp timestamp;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|>%I64u|ec=%.20s:%d,%.50s\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|>%llu|ec=%.20s:%d,%.50s\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      id_, ec.category().name(), ec.value(), arg);
+
+  invoked_ = true;
+}
+
+void handler_tracking::completion::invocation_end()
+{
+  if (id_)
+  {
+    handler_tracking_timestamp timestamp;
+
+    write_line(
+#if defined(ASIO_WINDOWS)
+        "@asio|%I64u.%06I64u|<%I64u|\n",
+#else // defined(ASIO_WINDOWS)
+        "@asio|%llu.%06llu|<%llu|\n",
+#endif // defined(ASIO_WINDOWS)
+        timestamp.seconds, timestamp.microseconds, id_);
+
+    id_ = 0;
+  }
+}
+
+void handler_tracking::operation(execution_context&,
+    const char* object_type, void* object,
+    uintmax_t /*native_handle*/, const char* op_name)
+{
+  static tracking_state* state = get_state();
+
+  handler_tracking_timestamp timestamp;
+
+  unsigned long long current_id = 0;
+  if (completion* current_completion = *state->current_completion_)
+    current_id = current_completion->id_;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|%I64u|%.20s@%p.%.50s\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|%llu|%.20s@%p.%.50s\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      current_id, object_type, object, op_name);
+}
+
+void handler_tracking::reactor_registration(execution_context& /*context*/,
+    uintmax_t /*native_handle*/, uintmax_t /*registration*/)
+{
+}
+
+void handler_tracking::reactor_deregistration(execution_context& /*context*/,
+    uintmax_t /*native_handle*/, uintmax_t /*registration*/)
+{
+}
+
+void handler_tracking::reactor_events(execution_context& /*context*/,
+    uintmax_t /*native_handle*/, unsigned /*events*/)
+{
+}
+
+void handler_tracking::reactor_operation(
+    const tracked_handler& h, const char* op_name,
+    const asio::error_code& ec)
+{
+  handler_tracking_timestamp timestamp;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|.%I64u|%s,ec=%.20s:%d\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|.%llu|%s,ec=%.20s:%d\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      h.id_, op_name, ec.category().name(), ec.value());
+}
+
+void handler_tracking::reactor_operation(
+    const tracked_handler& h, const char* op_name,
+    const asio::error_code& ec, std::size_t bytes_transferred)
+{
+  handler_tracking_timestamp timestamp;
+
+  write_line(
+#if defined(ASIO_WINDOWS)
+      "@asio|%I64u.%06I64u|.%I64u|%s,ec=%.20s:%d,bytes_transferred=%I64u\n",
+#else // defined(ASIO_WINDOWS)
+      "@asio|%llu.%06llu|.%llu|%s,ec=%.20s:%d,bytes_transferred=%llu\n",
+#endif // defined(ASIO_WINDOWS)
+      timestamp.seconds, timestamp.microseconds,
+      h.id_, op_name, ec.category().name(), ec.value(),
+      static_cast<uint64_t>(bytes_transferred));
+}
+
+void handler_tracking::write_line(const char* format, ...)
+{
+  using namespace std; // For sprintf (or equivalent).
+
+  va_list args;
+  va_start(args, format);
+
+  char line[256] = "";
+#if defined(ASIO_HAS_SECURE_RTL)
+  int length = vsprintf_s(line, sizeof(line), format, args);
+#else // defined(ASIO_HAS_SECURE_RTL)
+  int length = vsprintf(line, format, args);
+#endif // defined(ASIO_HAS_SECURE_RTL)
+
+  va_end(args);
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+  wchar_t wline[256] = L"";
+  mbstowcs_s(0, wline, sizeof(wline) / sizeof(wchar_t), line, length);
+  ::OutputDebugStringW(wline);
+#elif defined(ASIO_WINDOWS)
+  HANDLE stderr_handle = ::GetStdHandle(STD_ERROR_HANDLE);
+  DWORD bytes_written = 0;
+  ::WriteFile(stderr_handle, line, length, &bytes_written, 0);
+#else // defined(ASIO_WINDOWS)
+  ::write(STDERR_FILENO, line, length);
+#endif // defined(ASIO_WINDOWS)
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+#endif // ASIO_DETAIL_IMPL_HANDLER_TRACKING_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/kqueue_reactor.hpp b/subprojects/asio/include/asio/detail/impl/kqueue_reactor.hpp
new file mode 100644
index 000000000..136d1678d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/kqueue_reactor.hpp
@@ -0,0 +1,93 @@
+//
+// detail/impl/kqueue_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2005 Stefan Arentz (stefan at soze dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_KQUEUE_REACTOR_HPP
+#define ASIO_DETAIL_IMPL_KQUEUE_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_KQUEUE)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+void kqueue_reactor::add_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_add_timer_queue(queue);
+}
+
+// Remove a timer queue from the reactor.
+template <typename Time_Traits>
+void kqueue_reactor::remove_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_remove_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void kqueue_reactor::schedule_timer(timer_queue<Time_Traits>& queue,
+    const typename Time_Traits::time_type& time,
+    typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op)
+{
+  mutex::scoped_lock lock(mutex_);
+
+  if (shutdown_)
+  {
+    scheduler_.post_immediate_completion(op, false);
+    return;
+  }
+
+  bool earliest = queue.enqueue_timer(time, timer, op);
+  scheduler_.work_started();
+  if (earliest)
+    interrupt();
+}
+
+template <typename Time_Traits>
+std::size_t kqueue_reactor::cancel_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& timer,
+    std::size_t max_cancelled)
+{
+  mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  std::size_t n = queue.cancel_timer(timer, ops, max_cancelled);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+  return n;
+}
+
+template <typename Time_Traits>
+void kqueue_reactor::move_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& target,
+    typename timer_queue<Time_Traits>::per_timer_data& source)
+{
+  mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  queue.cancel_timer(target, ops);
+  queue.move_timer(target, source);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_KQUEUE)
+
+#endif // ASIO_DETAIL_IMPL_KQUEUE_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/kqueue_reactor.ipp b/subprojects/asio/include/asio/detail/impl/kqueue_reactor.ipp
new file mode 100644
index 000000000..73986e0e6
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/kqueue_reactor.ipp
@@ -0,0 +1,566 @@
+//
+// detail/impl/kqueue_reactor.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2005 Stefan Arentz (stefan at soze dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_KQUEUE_REACTOR_IPP
+#define ASIO_DETAIL_IMPL_KQUEUE_REACTOR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_KQUEUE)
+
+#include "asio/detail/kqueue_reactor.hpp"
+#include "asio/detail/scheduler.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+#if defined(__NetBSD__)
+# define ASIO_KQUEUE_EV_SET(ev, ident, filt, flags, fflags, data, udata) \
+    EV_SET(ev, ident, filt, flags, fflags, data, \
+      reinterpret_cast<intptr_t>(static_cast<void*>(udata)))
+#else
+# define ASIO_KQUEUE_EV_SET(ev, ident, filt, flags, fflags, data, udata) \
+    EV_SET(ev, ident, filt, flags, fflags, data, udata)
+#endif
+
+namespace asio {
+namespace detail {
+
+kqueue_reactor::kqueue_reactor(asio::execution_context& ctx)
+  : execution_context_service_base<kqueue_reactor>(ctx),
+    scheduler_(use_service<scheduler>(ctx)),
+    mutex_(ASIO_CONCURRENCY_HINT_IS_LOCKING(
+          REACTOR_REGISTRATION, scheduler_.concurrency_hint())),
+    kqueue_fd_(do_kqueue_create()),
+    interrupter_(),
+    shutdown_(false),
+    registered_descriptors_mutex_(mutex_.enabled())
+{
+  struct kevent events[1];
+  ASIO_KQUEUE_EV_SET(&events[0], interrupter_.read_descriptor(),
+      EVFILT_READ, EV_ADD, 0, 0, &interrupter_);
+  if (::kevent(kqueue_fd_, events, 1, 0, 0, 0) == -1)
+  {
+    asio::error_code error(errno,
+        asio::error::get_system_category());
+    asio::detail::throw_error(error);
+  }
+}
+
+kqueue_reactor::~kqueue_reactor()
+{
+  close(kqueue_fd_);
+}
+
+void kqueue_reactor::shutdown()
+{
+  mutex::scoped_lock lock(mutex_);
+  shutdown_ = true;
+  lock.unlock();
+
+  op_queue<operation> ops;
+
+  while (descriptor_state* state = registered_descriptors_.first())
+  {
+    for (int i = 0; i < max_ops; ++i)
+      ops.push(state->op_queue_[i]);
+    state->shutdown_ = true;
+    registered_descriptors_.free(state);
+  }
+
+  timer_queues_.get_all_timers(ops);
+
+  scheduler_.abandon_operations(ops);
+}
+
+void kqueue_reactor::notify_fork(
+    asio::execution_context::fork_event fork_ev)
+{
+  if (fork_ev == asio::execution_context::fork_child)
+  {
+    // The kqueue descriptor is automatically closed in the child.
+    kqueue_fd_ = -1;
+    kqueue_fd_ = do_kqueue_create();
+
+    interrupter_.recreate();
+
+    struct kevent events[2];
+    ASIO_KQUEUE_EV_SET(&events[0], interrupter_.read_descriptor(),
+        EVFILT_READ, EV_ADD, 0, 0, &interrupter_);
+    if (::kevent(kqueue_fd_, events, 1, 0, 0, 0) == -1)
+    {
+      asio::error_code ec(errno,
+          asio::error::get_system_category());
+      asio::detail::throw_error(ec, "kqueue interrupter registration");
+    }
+
+    // Re-register all descriptors with kqueue.
+    mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
+    for (descriptor_state* state = registered_descriptors_.first();
+        state != 0; state = state->next_)
+    {
+      if (state->num_kevents_ > 0)
+      {
+        ASIO_KQUEUE_EV_SET(&events[0], state->descriptor_,
+            EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, state);
+        ASIO_KQUEUE_EV_SET(&events[1], state->descriptor_,
+            EVFILT_WRITE, EV_ADD | EV_CLEAR, 0, 0, state);
+        if (::kevent(kqueue_fd_, events, state->num_kevents_, 0, 0, 0) == -1)
+        {
+          asio::error_code ec(errno,
+              asio::error::get_system_category());
+          asio::detail::throw_error(ec, "kqueue re-registration");
+        }
+      }
+    }
+  }
+}
+
+void kqueue_reactor::init_task()
+{
+  scheduler_.init_task();
+}
+
+int kqueue_reactor::register_descriptor(socket_type descriptor,
+    kqueue_reactor::per_descriptor_data& descriptor_data)
+{
+  descriptor_data = allocate_descriptor_state();
+
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
+  mutex::scoped_lock lock(descriptor_data->mutex_);
+
+  descriptor_data->descriptor_ = descriptor;
+  descriptor_data->num_kevents_ = 0;
+  descriptor_data->shutdown_ = false;
+
+  return 0;
+}
+
+int kqueue_reactor::register_internal_descriptor(
+    int op_type, socket_type descriptor,
+    kqueue_reactor::per_descriptor_data& descriptor_data, reactor_op* op)
+{
+  descriptor_data = allocate_descriptor_state();
+
+  ASIO_HANDLER_REACTOR_REGISTRATION((
+        context(), static_cast<uintmax_t>(descriptor),
+        reinterpret_cast<uintmax_t>(descriptor_data)));
+
+  mutex::scoped_lock lock(descriptor_data->mutex_);
+
+  descriptor_data->descriptor_ = descriptor;
+  descriptor_data->num_kevents_ = 1;
+  descriptor_data->shutdown_ = false;
+  descriptor_data->op_queue_[op_type].push(op);
+
+  struct kevent events[1];
+  ASIO_KQUEUE_EV_SET(&events[0], descriptor, EVFILT_READ,
+      EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
+  if (::kevent(kqueue_fd_, events, 1, 0, 0, 0) == -1)
+    return errno;
+
+  return 0;
+}
+
+void kqueue_reactor::move_descriptor(socket_type,
+    kqueue_reactor::per_descriptor_data& target_descriptor_data,
+    kqueue_reactor::per_descriptor_data& source_descriptor_data)
+{
+  target_descriptor_data = source_descriptor_data;
+  source_descriptor_data = 0;
+}
+
+void kqueue_reactor::start_op(int op_type, socket_type descriptor,
+    kqueue_reactor::per_descriptor_data& descriptor_data, reactor_op* op,
+    bool is_continuation, bool allow_speculative)
+{
+  if (!descriptor_data)
+  {
+    op->ec_ = asio::error::bad_descriptor;
+    post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  if (descriptor_data->shutdown_)
+  {
+    post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  if (descriptor_data->op_queue_[op_type].empty())
+  {
+    static const int num_kevents[max_ops] = { 1, 2, 1 };
+
+    if (allow_speculative
+        && (op_type != read_op
+          || descriptor_data->op_queue_[except_op].empty()))
+    {
+      if (op->perform())
+      {
+        descriptor_lock.unlock();
+        scheduler_.post_immediate_completion(op, is_continuation);
+        return;
+      }
+
+      if (descriptor_data->num_kevents_ < num_kevents[op_type])
+      {
+        struct kevent events[2];
+        ASIO_KQUEUE_EV_SET(&events[0], descriptor, EVFILT_READ,
+            EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
+        ASIO_KQUEUE_EV_SET(&events[1], descriptor, EVFILT_WRITE,
+            EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
+        if (::kevent(kqueue_fd_, events, num_kevents[op_type], 0, 0, 0) != -1)
+        {
+          descriptor_data->num_kevents_ = num_kevents[op_type];
+        }
+        else
+        {
+          op->ec_ = asio::error_code(errno,
+              asio::error::get_system_category());
+          scheduler_.post_immediate_completion(op, is_continuation);
+          return;
+        }
+      }
+    }
+    else
+    {
+      if (descriptor_data->num_kevents_ < num_kevents[op_type])
+        descriptor_data->num_kevents_ = num_kevents[op_type];
+
+      struct kevent events[2];
+      ASIO_KQUEUE_EV_SET(&events[0], descriptor, EVFILT_READ,
+          EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
+      ASIO_KQUEUE_EV_SET(&events[1], descriptor, EVFILT_WRITE,
+          EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
+      ::kevent(kqueue_fd_, events, descriptor_data->num_kevents_, 0, 0, 0);
+    }
+  }
+
+  descriptor_data->op_queue_[op_type].push(op);
+  scheduler_.work_started();
+}
+
+void kqueue_reactor::cancel_ops(socket_type,
+    kqueue_reactor::per_descriptor_data& descriptor_data)
+{
+  if (!descriptor_data)
+    return;
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  op_queue<operation> ops;
+  for (int i = 0; i < max_ops; ++i)
+  {
+    while (reactor_op* op = descriptor_data->op_queue_[i].front())
+    {
+      op->ec_ = asio::error::operation_aborted;
+      descriptor_data->op_queue_[i].pop();
+      ops.push(op);
+    }
+  }
+
+  descriptor_lock.unlock();
+
+  scheduler_.post_deferred_completions(ops);
+}
+
+void kqueue_reactor::deregister_descriptor(socket_type descriptor,
+    kqueue_reactor::per_descriptor_data& descriptor_data, bool closing)
+{
+  if (!descriptor_data)
+    return;
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  if (!descriptor_data->shutdown_)
+  {
+    if (closing)
+    {
+      // The descriptor will be automatically removed from the kqueue when it
+      // is closed.
+    }
+    else
+    {
+      struct kevent events[2];
+      ASIO_KQUEUE_EV_SET(&events[0], descriptor,
+          EVFILT_READ, EV_DELETE, 0, 0, 0);
+      ASIO_KQUEUE_EV_SET(&events[1], descriptor,
+          EVFILT_WRITE, EV_DELETE, 0, 0, 0);
+      ::kevent(kqueue_fd_, events, descriptor_data->num_kevents_, 0, 0, 0);
+    }
+
+    op_queue<operation> ops;
+    for (int i = 0; i < max_ops; ++i)
+    {
+      while (reactor_op* op = descriptor_data->op_queue_[i].front())
+      {
+        op->ec_ = asio::error::operation_aborted;
+        descriptor_data->op_queue_[i].pop();
+        ops.push(op);
+      }
+    }
+
+    descriptor_data->descriptor_ = -1;
+    descriptor_data->shutdown_ = true;
+
+    descriptor_lock.unlock();
+
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
+    scheduler_.post_deferred_completions(ops);
+
+    // Leave descriptor_data set so that it will be freed by the subsequent
+    // call to cleanup_descriptor_data.
+  }
+  else
+  {
+    // We are shutting down, so prevent cleanup_descriptor_data from freeing
+    // the descriptor_data object and let the destructor free it instead.
+    descriptor_data = 0;
+  }
+}
+
+void kqueue_reactor::deregister_internal_descriptor(socket_type descriptor,
+    kqueue_reactor::per_descriptor_data& descriptor_data)
+{
+  if (!descriptor_data)
+    return;
+
+  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+  if (!descriptor_data->shutdown_)
+  {
+    struct kevent events[2];
+    ASIO_KQUEUE_EV_SET(&events[0], descriptor,
+        EVFILT_READ, EV_DELETE, 0, 0, 0);
+    ASIO_KQUEUE_EV_SET(&events[1], descriptor,
+        EVFILT_WRITE, EV_DELETE, 0, 0, 0);
+    ::kevent(kqueue_fd_, events, descriptor_data->num_kevents_, 0, 0, 0);
+
+    op_queue<operation> ops;
+    for (int i = 0; i < max_ops; ++i)
+      ops.push(descriptor_data->op_queue_[i]);
+
+    descriptor_data->descriptor_ = -1;
+    descriptor_data->shutdown_ = true;
+
+    descriptor_lock.unlock();
+
+    ASIO_HANDLER_REACTOR_DEREGISTRATION((
+          context(), static_cast<uintmax_t>(descriptor),
+          reinterpret_cast<uintmax_t>(descriptor_data)));
+
+    // Leave descriptor_data set so that it will be freed by the subsequent
+    // call to cleanup_descriptor_data.
+  }
+  else
+  {
+    // We are shutting down, so prevent cleanup_descriptor_data from freeing
+    // the descriptor_data object and let the destructor free it instead.
+    descriptor_data = 0;
+  }
+}
+
+void kqueue_reactor::cleanup_descriptor_data(
+    per_descriptor_data& descriptor_data)
+{
+  if (descriptor_data)
+  {
+    free_descriptor_state(descriptor_data);
+    descriptor_data = 0;
+  }
+}
+
+void kqueue_reactor::run(long usec, op_queue<operation>& ops)
+{
+  mutex::scoped_lock lock(mutex_);
+
+  // Determine how long to block while waiting for events.
+  timespec timeout_buf = { 0, 0 };
+  timespec* timeout = usec ? get_timeout(usec, timeout_buf) : &timeout_buf;
+
+  lock.unlock();
+
+  // Block on the kqueue descriptor.
+  struct kevent events[128];
+  int num_events = kevent(kqueue_fd_, 0, 0, events, 128, timeout);
+
+#if defined(ASIO_ENABLE_HANDLER_TRACKING)
+  // Trace the waiting events.
+  for (int i = 0; i < num_events; ++i)
+  {
+    void* ptr = reinterpret_cast<void*>(events[i].udata);
+    if (ptr != &interrupter_)
+    {
+      unsigned event_mask = 0;
+      switch (events[i].filter)
+      {
+      case EVFILT_READ:
+        event_mask |= ASIO_HANDLER_REACTOR_READ_EVENT;
+        break;
+      case EVFILT_WRITE:
+        event_mask |= ASIO_HANDLER_REACTOR_WRITE_EVENT;
+        break;
+      }
+      if ((events[i].flags & (EV_ERROR | EV_OOBAND)) != 0)
+        event_mask |= ASIO_HANDLER_REACTOR_ERROR_EVENT;
+      ASIO_HANDLER_REACTOR_EVENTS((context(),
+            reinterpret_cast<uintmax_t>(ptr), event_mask));
+    }
+  }
+#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
+
+  // Dispatch the waiting events.
+  for (int i = 0; i < num_events; ++i)
+  {
+    void* ptr = reinterpret_cast<void*>(events[i].udata);
+    if (ptr == &interrupter_)
+    {
+      interrupter_.reset();
+    }
+    else
+    {
+      descriptor_state* descriptor_data = static_cast<descriptor_state*>(ptr);
+      mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
+
+      if (events[i].filter == EVFILT_WRITE
+          && descriptor_data->num_kevents_ == 2
+          && descriptor_data->op_queue_[write_op].empty())
+      {
+        // Some descriptor types, like serial ports, don't seem to support
+        // EV_CLEAR with EVFILT_WRITE. Since we have no pending write
+        // operations we'll remove the EVFILT_WRITE registration here so that
+        // we don't end up in a tight spin.
+        struct kevent delete_events[1];
+        ASIO_KQUEUE_EV_SET(&delete_events[0],
+            descriptor_data->descriptor_, EVFILT_WRITE, EV_DELETE, 0, 0, 0);
+        ::kevent(kqueue_fd_, delete_events, 1, 0, 0, 0);
+        descriptor_data->num_kevents_ = 1;
+      }
+
+      // Exception operations must be processed first to ensure that any
+      // out-of-band data is read before normal data.
+#if defined(__NetBSD__)
+      static const unsigned int filter[max_ops] =
+#else
+      static const int filter[max_ops] =
+#endif
+        { EVFILT_READ, EVFILT_WRITE, EVFILT_READ };
+      for (int j = max_ops - 1; j >= 0; --j)
+      {
+        if (events[i].filter == filter[j])
+        {
+          if (j != except_op || events[i].flags & EV_OOBAND)
+          {
+            while (reactor_op* op = descriptor_data->op_queue_[j].front())
+            {
+              if (events[i].flags & EV_ERROR)
+              {
+                op->ec_ = asio::error_code(
+                    static_cast<int>(events[i].data),
+                    asio::error::get_system_category());
+                descriptor_data->op_queue_[j].pop();
+                ops.push(op);
+              }
+              if (op->perform())
+              {
+                descriptor_data->op_queue_[j].pop();
+                ops.push(op);
+              }
+              else
+                break;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  lock.lock();
+  timer_queues_.get_ready_timers(ops);
+}
+
+void kqueue_reactor::interrupt()
+{
+  interrupter_.interrupt();
+}
+
+int kqueue_reactor::do_kqueue_create()
+{
+  int fd = ::kqueue();
+  if (fd == -1)
+  {
+    asio::error_code ec(errno,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "kqueue");
+  }
+  return fd;
+}
+
+kqueue_reactor::descriptor_state* kqueue_reactor::allocate_descriptor_state()
+{
+  mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
+  return registered_descriptors_.alloc(ASIO_CONCURRENCY_HINT_IS_LOCKING(
+        REACTOR_IO, scheduler_.concurrency_hint()));
+}
+
+void kqueue_reactor::free_descriptor_state(kqueue_reactor::descriptor_state* s)
+{
+  mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
+  registered_descriptors_.free(s);
+}
+
+void kqueue_reactor::do_add_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.insert(&queue);
+}
+
+void kqueue_reactor::do_remove_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.erase(&queue);
+}
+
+timespec* kqueue_reactor::get_timeout(long usec, timespec& ts)
+{
+  // By default we will wait no longer than 5 minutes. This will ensure that
+  // any changes to the system clock are detected after no longer than this.
+  const long max_usec = 5 * 60 * 1000 * 1000;
+  usec = timer_queues_.wait_duration_usec(
+      (usec < 0 || max_usec < usec) ? max_usec : usec);
+  ts.tv_sec = usec / 1000000;
+  ts.tv_nsec = (usec % 1000000) * 1000;
+  return &ts;
+}
+
+} // namespace detail
+} // namespace asio
+
+#undef ASIO_KQUEUE_EV_SET
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_KQUEUE)
+
+#endif // ASIO_DETAIL_IMPL_KQUEUE_REACTOR_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/null_event.ipp b/subprojects/asio/include/asio/detail/impl/null_event.ipp
new file mode 100644
index 000000000..22ade40b6
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/null_event.ipp
@@ -0,0 +1,74 @@
+//
+// detail/impl/null_event.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_NULL_EVENT_IPP
+#define ASIO_DETAIL_IMPL_NULL_EVENT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include <thread>
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# include "asio/detail/socket_types.hpp"
+#else
+# include <unistd.h>
+# if defined(__hpux)
+#  include <sys/time.h>
+# endif
+# if !defined(__hpux) || defined(__SELECT)
+#  include <sys/select.h>
+# endif
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+void null_event::do_wait()
+{
+#if defined(ASIO_WINDOWS_RUNTIME)
+  std::this_thread::sleep_until((std::chrono::steady_clock::time_point::max)());
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  ::Sleep(INFINITE);
+#else
+  ::pause();
+#endif
+}
+
+void null_event::do_wait_for_usec(long usec)
+{
+#if defined(ASIO_WINDOWS_RUNTIME)
+  std::this_thread::sleep_for(std::chrono::microseconds(usec));
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  ::Sleep(usec / 1000);
+#elif defined(__hpux) && defined(__SELECT)
+  timespec ts;
+  ts.tv_sec = usec / 1000000;
+  ts.tv_nsec = (usec % 1000000) * 1000;
+  ::pselect(0, 0, 0, 0, &ts, 0);
+#else
+  timeval tv;
+  tv.tv_sec = usec / 1000000;
+  tv.tv_usec = usec % 1000000;
+  ::select(0, 0, 0, 0, &tv);
+#endif
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_NULL_EVENT_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/pipe_select_interrupter.ipp b/subprojects/asio/include/asio/detail/impl/pipe_select_interrupter.ipp
new file mode 100644
index 000000000..13931ab82
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/pipe_select_interrupter.ipp
@@ -0,0 +1,124 @@
+//
+// detail/impl/pipe_select_interrupter.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_PIPE_SELECT_INTERRUPTER_IPP
+#define ASIO_DETAIL_IMPL_PIPE_SELECT_INTERRUPTER_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+#if !defined(ASIO_WINDOWS)
+#if !defined(__CYGWIN__)
+#if !defined(__SYMBIAN32__)
+#if !defined(ASIO_HAS_EVENTFD)
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "asio/detail/pipe_select_interrupter.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+pipe_select_interrupter::pipe_select_interrupter()
+{
+  open_descriptors();
+}
+
+void pipe_select_interrupter::open_descriptors()
+{
+  int pipe_fds[2];
+  if (pipe(pipe_fds) == 0)
+  {
+    read_descriptor_ = pipe_fds[0];
+    ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
+    write_descriptor_ = pipe_fds[1];
+    ::fcntl(write_descriptor_, F_SETFL, O_NONBLOCK);
+
+#if defined(FD_CLOEXEC)
+    ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
+    ::fcntl(write_descriptor_, F_SETFD, FD_CLOEXEC);
+#endif // defined(FD_CLOEXEC)
+  }
+  else
+  {
+    asio::error_code ec(errno,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "pipe_select_interrupter");
+  }
+}
+
+pipe_select_interrupter::~pipe_select_interrupter()
+{
+  close_descriptors();
+}
+
+void pipe_select_interrupter::close_descriptors()
+{
+  if (read_descriptor_ != -1)
+    ::close(read_descriptor_);
+  if (write_descriptor_ != -1)
+    ::close(write_descriptor_);
+}
+
+void pipe_select_interrupter::recreate()
+{
+  close_descriptors();
+
+  write_descriptor_ = -1;
+  read_descriptor_ = -1;
+
+  open_descriptors();
+}
+
+void pipe_select_interrupter::interrupt()
+{
+  char byte = 0;
+  signed_size_type result = ::write(write_descriptor_, &byte, 1);
+  (void)result;
+}
+
+bool pipe_select_interrupter::reset()
+{
+  for (;;)
+  {
+    char data[1024];
+    signed_size_type bytes_read = ::read(read_descriptor_, data, sizeof(data));
+    if (bytes_read < 0 && errno == EINTR)
+      continue;
+    bool was_interrupted = (bytes_read > 0);
+    while (bytes_read == sizeof(data))
+      bytes_read = ::read(read_descriptor_, data, sizeof(data));
+    return was_interrupted;
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_EVENTFD)
+#endif // !defined(__SYMBIAN32__)
+#endif // !defined(__CYGWIN__)
+#endif // !defined(ASIO_WINDOWS)
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_IMPL_PIPE_SELECT_INTERRUPTER_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/posix_event.ipp b/subprojects/asio/include/asio/detail/impl/posix_event.ipp
new file mode 100644
index 000000000..4b46ab082
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/posix_event.ipp
@@ -0,0 +1,59 @@
+//
+// detail/impl/posix_event.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_POSIX_EVENT_IPP
+#define ASIO_DETAIL_IMPL_POSIX_EVENT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include "asio/detail/posix_event.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+posix_event::posix_event()
+  : state_(0)
+{
+#if (defined(__MACH__) && defined(__APPLE__)) \
+      || (defined(__ANDROID__) && (__ANDROID_API__ < 21))
+  int error = ::pthread_cond_init(&cond_, 0);
+#else // (defined(__MACH__) && defined(__APPLE__))
+      // || (defined(__ANDROID__) && (__ANDROID_API__ < 21))
+  ::pthread_condattr_t attr;
+  ::pthread_condattr_init(&attr);
+  int error = ::pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
+  if (error == 0)
+    error = ::pthread_cond_init(&cond_, &attr);
+#endif // (defined(__MACH__) && defined(__APPLE__))
+       // || (defined(__ANDROID__) && (__ANDROID_API__ < 21))
+
+  asio::error_code ec(error,
+      asio::error::get_system_category());
+  asio::detail::throw_error(ec, "event");
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_IMPL_POSIX_EVENT_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/posix_mutex.ipp b/subprojects/asio/include/asio/detail/impl/posix_mutex.ipp
new file mode 100644
index 000000000..27272b57f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/posix_mutex.ipp
@@ -0,0 +1,46 @@
+//
+// detail/impl/posix_mutex.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_POSIX_MUTEX_IPP
+#define ASIO_DETAIL_IMPL_POSIX_MUTEX_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include "asio/detail/posix_mutex.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+posix_mutex::posix_mutex()
+{
+  int error = ::pthread_mutex_init(&mutex_, 0);
+  asio::error_code ec(error,
+      asio::error::get_system_category());
+  asio::detail::throw_error(ec, "mutex");
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_IMPL_POSIX_MUTEX_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/posix_thread.ipp b/subprojects/asio/include/asio/detail/impl/posix_thread.ipp
new file mode 100644
index 000000000..69bd16f9f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/posix_thread.ipp
@@ -0,0 +1,84 @@
+//
+// detail/impl/posix_thread.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_POSIX_THREAD_IPP
+#define ASIO_DETAIL_IMPL_POSIX_THREAD_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include "asio/detail/posix_thread.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+posix_thread::~posix_thread()
+{
+  if (!joined_)
+    ::pthread_detach(thread_);
+}
+
+void posix_thread::join()
+{
+  if (!joined_)
+  {
+    ::pthread_join(thread_, 0);
+    joined_ = true;
+  }
+}
+
+std::size_t posix_thread::hardware_concurrency()
+{
+#if defined(_SC_NPROCESSORS_ONLN)
+  long result = sysconf(_SC_NPROCESSORS_ONLN);
+  if (result > 0)
+    return result;
+#endif // defined(_SC_NPROCESSORS_ONLN)
+  return 0;
+}
+
+void posix_thread::start_thread(func_base* arg)
+{
+  int error = ::pthread_create(&thread_, 0,
+        asio_detail_posix_thread_function, arg);
+  if (error != 0)
+  {
+    delete arg;
+    asio::error_code ec(error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "thread");
+  }
+}
+
+void* asio_detail_posix_thread_function(void* arg)
+{
+  posix_thread::auto_func_base_ptr func = {
+      static_cast<posix_thread::func_base*>(arg) };
+  func.ptr->run();
+  return 0;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_IMPL_POSIX_THREAD_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/posix_tss_ptr.ipp b/subprojects/asio/include/asio/detail/impl/posix_tss_ptr.ipp
new file mode 100644
index 000000000..54b58bd1e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/posix_tss_ptr.ipp
@@ -0,0 +1,46 @@
+//
+// detail/impl/posix_tss_ptr.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_POSIX_TSS_PTR_IPP
+#define ASIO_DETAIL_IMPL_POSIX_TSS_PTR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include "asio/detail/posix_tss_ptr.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+void posix_tss_ptr_create(pthread_key_t& key)
+{
+  int error = ::pthread_key_create(&key, 0);
+  asio::error_code ec(error,
+      asio::error::get_system_category());
+  asio::detail::throw_error(ec, "tss");
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_IMPL_POSIX_TSS_PTR_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/reactive_descriptor_service.ipp b/subprojects/asio/include/asio/detail/impl/reactive_descriptor_service.ipp
new file mode 100644
index 000000000..f9505ca95
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/reactive_descriptor_service.ipp
@@ -0,0 +1,222 @@
+//
+// detail/impl/reactive_descriptor_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_REACTIVE_DESCRIPTOR_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_REACTIVE_DESCRIPTOR_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+
+#include "asio/error.hpp"
+#include "asio/detail/reactive_descriptor_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+reactive_descriptor_service::reactive_descriptor_service(
+    asio::io_context& io_context)
+  : service_base<reactive_descriptor_service>(io_context),
+    reactor_(asio::use_service<reactor>(io_context))
+{
+  reactor_.init_task();
+}
+
+void reactive_descriptor_service::shutdown()
+{
+}
+
+void reactive_descriptor_service::construct(
+    reactive_descriptor_service::implementation_type& impl)
+{
+  impl.descriptor_ = -1;
+  impl.state_ = 0;
+}
+
+void reactive_descriptor_service::move_construct(
+    reactive_descriptor_service::implementation_type& impl,
+    reactive_descriptor_service::implementation_type& other_impl)
+{
+  impl.descriptor_ = other_impl.descriptor_;
+  other_impl.descriptor_ = -1;
+
+  impl.state_ = other_impl.state_;
+  other_impl.state_ = 0;
+
+  reactor_.move_descriptor(impl.descriptor_,
+      impl.reactor_data_, other_impl.reactor_data_);
+}
+
+void reactive_descriptor_service::move_assign(
+    reactive_descriptor_service::implementation_type& impl,
+    reactive_descriptor_service& other_service,
+    reactive_descriptor_service::implementation_type& other_impl)
+{
+  destroy(impl);
+
+  impl.descriptor_ = other_impl.descriptor_;
+  other_impl.descriptor_ = -1;
+
+  impl.state_ = other_impl.state_;
+  other_impl.state_ = 0;
+
+  other_service.reactor_.move_descriptor(impl.descriptor_,
+      impl.reactor_data_, other_impl.reactor_data_);
+}
+
+void reactive_descriptor_service::destroy(
+    reactive_descriptor_service::implementation_type& impl)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((reactor_.context(),
+          "descriptor", &impl, impl.descriptor_, "close"));
+
+    reactor_.deregister_descriptor(impl.descriptor_, impl.reactor_data_,
+        (impl.state_ & descriptor_ops::possible_dup) == 0);
+
+    asio::error_code ignored_ec;
+    descriptor_ops::close(impl.descriptor_, impl.state_, ignored_ec);
+
+    reactor_.cleanup_descriptor_data(impl.reactor_data_);
+  }
+}
+
+asio::error_code reactive_descriptor_service::assign(
+    reactive_descriptor_service::implementation_type& impl,
+    const native_handle_type& native_descriptor, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  if (int err = reactor_.register_descriptor(
+        native_descriptor, impl.reactor_data_))
+  {
+    ec = asio::error_code(err,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  impl.descriptor_ = native_descriptor;
+  impl.state_ = descriptor_ops::possible_dup;
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code reactive_descriptor_service::close(
+    reactive_descriptor_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((reactor_.context(),
+          "descriptor", &impl, impl.descriptor_, "close"));
+
+    reactor_.deregister_descriptor(impl.descriptor_, impl.reactor_data_,
+        (impl.state_ & descriptor_ops::possible_dup) == 0);
+
+    descriptor_ops::close(impl.descriptor_, impl.state_, ec);
+
+    reactor_.cleanup_descriptor_data(impl.reactor_data_);
+  }
+  else
+  {
+    ec = asio::error_code();
+  }
+
+  // The descriptor is closed by the OS even if close() returns an error.
+  //
+  // (Actually, POSIX says the state of the descriptor is unspecified. On
+  // Linux the descriptor is apparently closed anyway; e.g. see
+  //   http://lkml.org/lkml/2005/9/10/129
+  // We'll just have to assume that other OSes follow the same behaviour.)
+  construct(impl);
+
+  return ec;
+}
+
+reactive_descriptor_service::native_handle_type
+reactive_descriptor_service::release(
+    reactive_descriptor_service::implementation_type& impl)
+{
+  native_handle_type descriptor = impl.descriptor_;
+
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((reactor_.context(),
+          "descriptor", &impl, impl.descriptor_, "release"));
+
+    reactor_.deregister_descriptor(impl.descriptor_, impl.reactor_data_, false);
+    reactor_.cleanup_descriptor_data(impl.reactor_data_);
+    construct(impl);
+  }
+
+  return descriptor;
+}
+
+asio::error_code reactive_descriptor_service::cancel(
+    reactive_descriptor_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return ec;
+  }
+
+  ASIO_HANDLER_OPERATION((reactor_.context(),
+        "descriptor", &impl, impl.descriptor_, "cancel"));
+
+  reactor_.cancel_ops(impl.descriptor_, impl.reactor_data_);
+  ec = asio::error_code();
+  return ec;
+}
+
+void reactive_descriptor_service::start_op(
+    reactive_descriptor_service::implementation_type& impl,
+    int op_type, reactor_op* op, bool is_continuation,
+    bool is_non_blocking, bool noop)
+{
+  if (!noop)
+  {
+    if ((impl.state_ & descriptor_ops::non_blocking) ||
+        descriptor_ops::set_internal_non_blocking(
+          impl.descriptor_, impl.state_, true, op->ec_))
+    {
+      reactor_.start_op(op_type, impl.descriptor_,
+          impl.reactor_data_, op, is_continuation, is_non_blocking);
+      return;
+    }
+  }
+
+  reactor_.post_immediate_completion(op, is_continuation);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_IMPL_REACTIVE_DESCRIPTOR_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/reactive_serial_port_service.ipp b/subprojects/asio/include/asio/detail/impl/reactive_serial_port_service.ipp
new file mode 100644
index 000000000..c907835c7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/reactive_serial_port_service.ipp
@@ -0,0 +1,152 @@
+//
+// detail/impl/reactive_serial_port_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_REACTIVE_SERIAL_PORT_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_REACTIVE_SERIAL_PORT_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_SERIAL_PORT)
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include <cstring>
+#include "asio/detail/reactive_serial_port_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+reactive_serial_port_service::reactive_serial_port_service(
+    asio::io_context& io_context)
+  : service_base<reactive_serial_port_service>(io_context),
+    descriptor_service_(io_context)
+{
+}
+
+void reactive_serial_port_service::shutdown()
+{
+  descriptor_service_.shutdown();
+}
+
+asio::error_code reactive_serial_port_service::open(
+    reactive_serial_port_service::implementation_type& impl,
+    const std::string& device, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  descriptor_ops::state_type state = 0;
+  int fd = descriptor_ops::open(device.c_str(),
+      O_RDWR | O_NONBLOCK | O_NOCTTY, ec);
+  if (fd < 0)
+    return ec;
+
+  int s = descriptor_ops::fcntl(fd, F_GETFL, ec);
+  if (s >= 0)
+    s = descriptor_ops::fcntl(fd, F_SETFL, s | O_NONBLOCK, ec);
+  if (s < 0)
+  {
+    asio::error_code ignored_ec;
+    descriptor_ops::close(fd, state, ignored_ec);
+    return ec;
+  }
+
+  // Set up default serial port options.
+  termios ios;
+  errno = 0;
+  s = descriptor_ops::error_wrapper(::tcgetattr(fd, &ios), ec);
+  if (s >= 0)
+  {
+#if defined(_BSD_SOURCE) || defined(_DEFAULT_SOURCE)
+    ::cfmakeraw(&ios);
+#else
+    ios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK
+        | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
+    ios.c_oflag &= ~OPOST;
+    ios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+    ios.c_cflag &= ~(CSIZE | PARENB);
+    ios.c_cflag |= CS8;
+#endif
+    ios.c_iflag |= IGNPAR;
+    ios.c_cflag |= CREAD | CLOCAL;
+    errno = 0;
+    s = descriptor_ops::error_wrapper(::tcsetattr(fd, TCSANOW, &ios), ec);
+  }
+  if (s < 0)
+  {
+    asio::error_code ignored_ec;
+    descriptor_ops::close(fd, state, ignored_ec);
+    return ec;
+  }
+
+  // We're done. Take ownership of the serial port descriptor.
+  if (descriptor_service_.assign(impl, fd, ec))
+  {
+    asio::error_code ignored_ec;
+    descriptor_ops::close(fd, state, ignored_ec);
+  }
+
+  return ec;
+}
+
+asio::error_code reactive_serial_port_service::do_set_option(
+    reactive_serial_port_service::implementation_type& impl,
+    reactive_serial_port_service::store_function_type store,
+    const void* option, asio::error_code& ec)
+{
+  termios ios;
+  errno = 0;
+  descriptor_ops::error_wrapper(::tcgetattr(
+        descriptor_service_.native_handle(impl), &ios), ec);
+  if (ec)
+    return ec;
+
+  if (store(option, ios, ec))
+    return ec;
+
+  errno = 0;
+  descriptor_ops::error_wrapper(::tcsetattr(
+        descriptor_service_.native_handle(impl), TCSANOW, &ios), ec);
+  return ec;
+}
+
+asio::error_code reactive_serial_port_service::do_get_option(
+    const reactive_serial_port_service::implementation_type& impl,
+    reactive_serial_port_service::load_function_type load,
+    void* option, asio::error_code& ec) const
+{
+  termios ios;
+  errno = 0;
+  descriptor_ops::error_wrapper(::tcgetattr(
+        descriptor_service_.native_handle(impl), &ios), ec);
+  if (ec)
+    return ec;
+
+  return load(option, ios, ec);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+#endif // defined(ASIO_HAS_SERIAL_PORT)
+
+#endif // ASIO_DETAIL_IMPL_REACTIVE_SERIAL_PORT_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/reactive_socket_service_base.ipp b/subprojects/asio/include/asio/detail/impl/reactive_socket_service_base.ipp
new file mode 100644
index 000000000..129b851da
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/reactive_socket_service_base.ipp
@@ -0,0 +1,300 @@
+//
+// detail/reactive_socket_service_base.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_REACTIVE_SOCKET_SERVICE_BASE_IPP
+#define ASIO_DETAIL_IMPL_REACTIVE_SOCKET_SERVICE_BASE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_IOCP) \
+  && !defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/reactive_socket_service_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+reactive_socket_service_base::reactive_socket_service_base(
+    asio::io_context& io_context)
+  : io_context_(io_context),
+    reactor_(use_service<reactor>(io_context))
+{
+  reactor_.init_task();
+}
+
+void reactive_socket_service_base::base_shutdown()
+{
+}
+
+void reactive_socket_service_base::construct(
+    reactive_socket_service_base::base_implementation_type& impl)
+{
+  impl.socket_ = invalid_socket;
+  impl.state_ = 0;
+}
+
+void reactive_socket_service_base::base_move_construct(
+    reactive_socket_service_base::base_implementation_type& impl,
+    reactive_socket_service_base::base_implementation_type& other_impl)
+{
+  impl.socket_ = other_impl.socket_;
+  other_impl.socket_ = invalid_socket;
+
+  impl.state_ = other_impl.state_;
+  other_impl.state_ = 0;
+
+  reactor_.move_descriptor(impl.socket_,
+      impl.reactor_data_, other_impl.reactor_data_);
+}
+
+void reactive_socket_service_base::base_move_assign(
+    reactive_socket_service_base::base_implementation_type& impl,
+    reactive_socket_service_base& other_service,
+    reactive_socket_service_base::base_implementation_type& other_impl)
+{
+  destroy(impl);
+
+  impl.socket_ = other_impl.socket_;
+  other_impl.socket_ = invalid_socket;
+
+  impl.state_ = other_impl.state_;
+  other_impl.state_ = 0;
+
+  other_service.reactor_.move_descriptor(impl.socket_,
+      impl.reactor_data_, other_impl.reactor_data_);
+}
+
+void reactive_socket_service_base::destroy(
+    reactive_socket_service_base::base_implementation_type& impl)
+{
+  if (impl.socket_ != invalid_socket)
+  {
+    ASIO_HANDLER_OPERATION((reactor_.context(),
+          "socket", &impl, impl.socket_, "close"));
+
+    reactor_.deregister_descriptor(impl.socket_, impl.reactor_data_,
+        (impl.state_ & socket_ops::possible_dup) == 0);
+
+    asio::error_code ignored_ec;
+    socket_ops::close(impl.socket_, impl.state_, true, ignored_ec);
+
+    reactor_.cleanup_descriptor_data(impl.reactor_data_);
+  }
+}
+
+asio::error_code reactive_socket_service_base::close(
+    reactive_socket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((reactor_.context(),
+          "socket", &impl, impl.socket_, "close"));
+
+    reactor_.deregister_descriptor(impl.socket_, impl.reactor_data_,
+        (impl.state_ & socket_ops::possible_dup) == 0);
+
+    socket_ops::close(impl.socket_, impl.state_, false, ec);
+
+    reactor_.cleanup_descriptor_data(impl.reactor_data_);
+  }
+  else
+  {
+    ec = asio::error_code();
+  }
+
+  // The descriptor is closed by the OS even if close() returns an error.
+  //
+  // (Actually, POSIX says the state of the descriptor is unspecified. On
+  // Linux the descriptor is apparently closed anyway; e.g. see
+  //   http://lkml.org/lkml/2005/9/10/129
+  // We'll just have to assume that other OSes follow the same behaviour. The
+  // known exception is when Windows's closesocket() function fails with
+  // WSAEWOULDBLOCK, but this case is handled inside socket_ops::close().
+  construct(impl);
+
+  return ec;
+}
+
+socket_type reactive_socket_service_base::release(
+    reactive_socket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return invalid_socket;
+  }
+
+  ASIO_HANDLER_OPERATION((reactor_.context(),
+        "socket", &impl, impl.socket_, "release"));
+
+  reactor_.deregister_descriptor(impl.socket_, impl.reactor_data_, false);
+  reactor_.cleanup_descriptor_data(impl.reactor_data_);
+  socket_type sock = impl.socket_;
+  construct(impl);
+  ec = asio::error_code();
+  return sock;
+}
+
+asio::error_code reactive_socket_service_base::cancel(
+    reactive_socket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return ec;
+  }
+
+  ASIO_HANDLER_OPERATION((reactor_.context(),
+        "socket", &impl, impl.socket_, "cancel"));
+
+  reactor_.cancel_ops(impl.socket_, impl.reactor_data_);
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code reactive_socket_service_base::do_open(
+    reactive_socket_service_base::base_implementation_type& impl,
+    int af, int type, int protocol, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  socket_holder sock(socket_ops::socket(af, type, protocol, ec));
+  if (sock.get() == invalid_socket)
+    return ec;
+
+  if (int err = reactor_.register_descriptor(sock.get(), impl.reactor_data_))
+  {
+    ec = asio::error_code(err,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  impl.socket_ = sock.release();
+  switch (type)
+  {
+  case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break;
+  case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break;
+  default: impl.state_ = 0; break;
+  }
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code reactive_socket_service_base::do_assign(
+    reactive_socket_service_base::base_implementation_type& impl, int type,
+    const reactive_socket_service_base::native_handle_type& native_socket,
+    asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  if (int err = reactor_.register_descriptor(
+        native_socket, impl.reactor_data_))
+  {
+    ec = asio::error_code(err,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  impl.socket_ = native_socket;
+  switch (type)
+  {
+  case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break;
+  case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break;
+  default: impl.state_ = 0; break;
+  }
+  impl.state_ |= socket_ops::possible_dup;
+  ec = asio::error_code();
+  return ec;
+}
+
+void reactive_socket_service_base::start_op(
+    reactive_socket_service_base::base_implementation_type& impl,
+    int op_type, reactor_op* op, bool is_continuation,
+    bool is_non_blocking, bool noop)
+{
+  if (!noop)
+  {
+    if ((impl.state_ & socket_ops::non_blocking)
+        || socket_ops::set_internal_non_blocking(
+          impl.socket_, impl.state_, true, op->ec_))
+    {
+      reactor_.start_op(op_type, impl.socket_,
+          impl.reactor_data_, op, is_continuation, is_non_blocking);
+      return;
+    }
+  }
+
+  reactor_.post_immediate_completion(op, is_continuation);
+}
+
+void reactive_socket_service_base::start_accept_op(
+    reactive_socket_service_base::base_implementation_type& impl,
+    reactor_op* op, bool is_continuation, bool peer_is_open)
+{
+  if (!peer_is_open)
+    start_op(impl, reactor::read_op, op, is_continuation, true, false);
+  else
+  {
+    op->ec_ = asio::error::already_open;
+    reactor_.post_immediate_completion(op, is_continuation);
+  }
+}
+
+void reactive_socket_service_base::start_connect_op(
+    reactive_socket_service_base::base_implementation_type& impl,
+    reactor_op* op, bool is_continuation,
+    const socket_addr_type* addr, size_t addrlen)
+{
+  if ((impl.state_ & socket_ops::non_blocking)
+      || socket_ops::set_internal_non_blocking(
+        impl.socket_, impl.state_, true, op->ec_))
+  {
+    if (socket_ops::connect(impl.socket_, addr, addrlen, op->ec_) != 0)
+    {
+      if (op->ec_ == asio::error::in_progress
+          || op->ec_ == asio::error::would_block)
+      {
+        op->ec_ = asio::error_code();
+        reactor_.start_op(reactor::connect_op, impl.socket_,
+            impl.reactor_data_, op, is_continuation, false);
+        return;
+      }
+    }
+  }
+
+  reactor_.post_immediate_completion(op, is_continuation);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_IOCP)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_IMPL_REACTIVE_SOCKET_SERVICE_BASE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/resolver_service_base.ipp b/subprojects/asio/include/asio/detail/impl/resolver_service_base.ipp
new file mode 100644
index 000000000..540bb66be
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/resolver_service_base.ipp
@@ -0,0 +1,154 @@
+//
+// detail/impl/resolver_service_base.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_RESOLVER_SERVICE_BASE_IPP
+#define ASIO_DETAIL_IMPL_RESOLVER_SERVICE_BASE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/resolver_service_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class resolver_service_base::work_io_context_runner
+{
+public:
+  work_io_context_runner(asio::io_context& io_context)
+    : io_context_(io_context) {}
+  void operator()() { io_context_.run(); }
+private:
+  asio::io_context& io_context_;
+};
+
+resolver_service_base::resolver_service_base(
+    asio::io_context& io_context)
+  : io_context_impl_(asio::use_service<io_context_impl>(io_context)),
+    work_io_context_(new asio::io_context(-1)),
+    work_io_context_impl_(asio::use_service<
+        io_context_impl>(*work_io_context_)),
+    work_(asio::make_work_guard(*work_io_context_)),
+    work_thread_(0)
+{
+}
+
+resolver_service_base::~resolver_service_base()
+{
+  base_shutdown();
+}
+
+void resolver_service_base::base_shutdown()
+{
+  work_.reset();
+  if (work_io_context_.get())
+  {
+    work_io_context_->stop();
+    if (work_thread_.get())
+    {
+      work_thread_->join();
+      work_thread_.reset();
+    }
+    work_io_context_.reset();
+  }
+}
+
+void resolver_service_base::base_notify_fork(
+    asio::io_context::fork_event fork_ev)
+{
+  if (work_thread_.get())
+  {
+    if (fork_ev == asio::io_context::fork_prepare)
+    {
+      work_io_context_->stop();
+      work_thread_->join();
+    }
+    else
+    {
+      work_io_context_->restart();
+      work_thread_.reset(new asio::detail::thread(
+            work_io_context_runner(*work_io_context_)));
+    }
+  }
+}
+
+void resolver_service_base::construct(
+    resolver_service_base::implementation_type& impl)
+{
+  impl.reset(static_cast<void*>(0), socket_ops::noop_deleter());
+}
+
+void resolver_service_base::destroy(
+    resolver_service_base::implementation_type& impl)
+{
+  ASIO_HANDLER_OPERATION((io_context_impl_.context(),
+        "resolver", &impl, 0, "cancel"));
+
+  impl.reset();
+}
+
+void resolver_service_base::move_construct(implementation_type& impl,
+    implementation_type& other_impl)
+{
+  impl = ASIO_MOVE_CAST(implementation_type)(other_impl);
+}
+
+void resolver_service_base::move_assign(implementation_type& impl,
+    resolver_service_base&, implementation_type& other_impl)
+{
+  destroy(impl);
+  impl = ASIO_MOVE_CAST(implementation_type)(other_impl);
+}
+
+void resolver_service_base::cancel(
+    resolver_service_base::implementation_type& impl)
+{
+  ASIO_HANDLER_OPERATION((io_context_impl_.context(),
+        "resolver", &impl, 0, "cancel"));
+
+  impl.reset(static_cast<void*>(0), socket_ops::noop_deleter());
+}
+
+void resolver_service_base::start_resolve_op(resolve_op* op)
+{
+  if (ASIO_CONCURRENCY_HINT_IS_LOCKING(SCHEDULER,
+        io_context_impl_.concurrency_hint()))
+  {
+    start_work_thread();
+    io_context_impl_.work_started();
+    work_io_context_impl_.post_immediate_completion(op, false);
+  }
+  else
+  {
+    op->ec_ = asio::error::operation_not_supported;
+    io_context_impl_.post_immediate_completion(op, false);
+  }
+}
+
+void resolver_service_base::start_work_thread()
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  if (!work_thread_.get())
+  {
+    work_thread_.reset(new asio::detail::thread(
+          work_io_context_runner(*work_io_context_)));
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_RESOLVER_SERVICE_BASE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/scheduler.ipp b/subprojects/asio/include/asio/detail/impl/scheduler.ipp
new file mode 100644
index 000000000..35bc67879
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/scheduler.ipp
@@ -0,0 +1,571 @@
+//
+// detail/impl/scheduler.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SCHEDULER_IPP
+#define ASIO_DETAIL_IMPL_SCHEDULER_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/concurrency_hint.hpp"
+#include "asio/detail/event.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/reactor.hpp"
+#include "asio/detail/scheduler.hpp"
+#include "asio/detail/scheduler_thread_info.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct scheduler::task_cleanup
+{
+  ~task_cleanup()
+  {
+    if (this_thread_->private_outstanding_work > 0)
+    {
+      asio::detail::increment(
+          scheduler_->outstanding_work_,
+          this_thread_->private_outstanding_work);
+    }
+    this_thread_->private_outstanding_work = 0;
+
+    // Enqueue the completed operations and reinsert the task at the end of
+    // the operation queue.
+    lock_->lock();
+    scheduler_->task_interrupted_ = true;
+    scheduler_->op_queue_.push(this_thread_->private_op_queue);
+    scheduler_->op_queue_.push(&scheduler_->task_operation_);
+  }
+
+  scheduler* scheduler_;
+  mutex::scoped_lock* lock_;
+  thread_info* this_thread_;
+};
+
+struct scheduler::work_cleanup
+{
+  ~work_cleanup()
+  {
+    if (this_thread_->private_outstanding_work > 1)
+    {
+      asio::detail::increment(
+          scheduler_->outstanding_work_,
+          this_thread_->private_outstanding_work - 1);
+    }
+    else if (this_thread_->private_outstanding_work < 1)
+    {
+      scheduler_->work_finished();
+    }
+    this_thread_->private_outstanding_work = 0;
+
+#if defined(ASIO_HAS_THREADS)
+    if (!this_thread_->private_op_queue.empty())
+    {
+      lock_->lock();
+      scheduler_->op_queue_.push(this_thread_->private_op_queue);
+    }
+#endif // defined(ASIO_HAS_THREADS)
+  }
+
+  scheduler* scheduler_;
+  mutex::scoped_lock* lock_;
+  thread_info* this_thread_;
+};
+
+scheduler::scheduler(
+    asio::execution_context& ctx, int concurrency_hint)
+  : asio::detail::execution_context_service_base<scheduler>(ctx),
+    one_thread_(concurrency_hint == 1
+        || !ASIO_CONCURRENCY_HINT_IS_LOCKING(
+          SCHEDULER, concurrency_hint)
+        || !ASIO_CONCURRENCY_HINT_IS_LOCKING(
+          REACTOR_IO, concurrency_hint)),
+    mutex_(ASIO_CONCURRENCY_HINT_IS_LOCKING(
+          SCHEDULER, concurrency_hint)),
+    task_(0),
+    task_interrupted_(true),
+    outstanding_work_(0),
+    stopped_(false),
+    shutdown_(false),
+    concurrency_hint_(concurrency_hint)
+{
+  ASIO_HANDLER_TRACKING_INIT;
+}
+
+void scheduler::shutdown()
+{
+  mutex::scoped_lock lock(mutex_);
+  shutdown_ = true;
+  lock.unlock();
+
+  // Destroy handler objects.
+  while (!op_queue_.empty())
+  {
+    operation* o = op_queue_.front();
+    op_queue_.pop();
+    if (o != &task_operation_)
+      o->destroy();
+  }
+
+  // Reset to initial state.
+  task_ = 0;
+}
+
+void scheduler::init_task()
+{
+  mutex::scoped_lock lock(mutex_);
+  if (!shutdown_ && !task_)
+  {
+    task_ = &use_service<reactor>(this->context());
+    op_queue_.push(&task_operation_);
+    wake_one_thread_and_unlock(lock);
+  }
+}
+
+std::size_t scheduler::run(asio::error_code& ec)
+{
+  ec = asio::error_code();
+  if (outstanding_work_ == 0)
+  {
+    stop();
+    return 0;
+  }
+
+  thread_info this_thread;
+  this_thread.private_outstanding_work = 0;
+  thread_call_stack::context ctx(this, this_thread);
+
+  mutex::scoped_lock lock(mutex_);
+
+  std::size_t n = 0;
+  for (; do_run_one(lock, this_thread, ec); lock.lock())
+    if (n != (std::numeric_limits<std::size_t>::max)())
+      ++n;
+  return n;
+}
+
+std::size_t scheduler::run_one(asio::error_code& ec)
+{
+  ec = asio::error_code();
+  if (outstanding_work_ == 0)
+  {
+    stop();
+    return 0;
+  }
+
+  thread_info this_thread;
+  this_thread.private_outstanding_work = 0;
+  thread_call_stack::context ctx(this, this_thread);
+
+  mutex::scoped_lock lock(mutex_);
+
+  return do_run_one(lock, this_thread, ec);
+}
+
+std::size_t scheduler::wait_one(long usec, asio::error_code& ec)
+{
+  ec = asio::error_code();
+  if (outstanding_work_ == 0)
+  {
+    stop();
+    return 0;
+  }
+
+  thread_info this_thread;
+  this_thread.private_outstanding_work = 0;
+  thread_call_stack::context ctx(this, this_thread);
+
+  mutex::scoped_lock lock(mutex_);
+
+  return do_wait_one(lock, this_thread, usec, ec);
+}
+
+std::size_t scheduler::poll(asio::error_code& ec)
+{
+  ec = asio::error_code();
+  if (outstanding_work_ == 0)
+  {
+    stop();
+    return 0;
+  }
+
+  thread_info this_thread;
+  this_thread.private_outstanding_work = 0;
+  thread_call_stack::context ctx(this, this_thread);
+
+  mutex::scoped_lock lock(mutex_);
+
+#if defined(ASIO_HAS_THREADS)
+  // We want to support nested calls to poll() and poll_one(), so any handlers
+  // that are already on a thread-private queue need to be put on to the main
+  // queue now.
+  if (one_thread_)
+    if (thread_info* outer_info = static_cast<thread_info*>(ctx.next_by_key()))
+      op_queue_.push(outer_info->private_op_queue);
+#endif // defined(ASIO_HAS_THREADS)
+
+  std::size_t n = 0;
+  for (; do_poll_one(lock, this_thread, ec); lock.lock())
+    if (n != (std::numeric_limits<std::size_t>::max)())
+      ++n;
+  return n;
+}
+
+std::size_t scheduler::poll_one(asio::error_code& ec)
+{
+  ec = asio::error_code();
+  if (outstanding_work_ == 0)
+  {
+    stop();
+    return 0;
+  }
+
+  thread_info this_thread;
+  this_thread.private_outstanding_work = 0;
+  thread_call_stack::context ctx(this, this_thread);
+
+  mutex::scoped_lock lock(mutex_);
+
+#if defined(ASIO_HAS_THREADS)
+  // We want to support nested calls to poll() and poll_one(), so any handlers
+  // that are already on a thread-private queue need to be put on to the main
+  // queue now.
+  if (one_thread_)
+    if (thread_info* outer_info = static_cast<thread_info*>(ctx.next_by_key()))
+      op_queue_.push(outer_info->private_op_queue);
+#endif // defined(ASIO_HAS_THREADS)
+
+  return do_poll_one(lock, this_thread, ec);
+}
+
+void scheduler::stop()
+{
+  mutex::scoped_lock lock(mutex_);
+  stop_all_threads(lock);
+}
+
+bool scheduler::stopped() const
+{
+  mutex::scoped_lock lock(mutex_);
+  return stopped_;
+}
+
+void scheduler::restart()
+{
+  mutex::scoped_lock lock(mutex_);
+  stopped_ = false;
+}
+
+void scheduler::compensating_work_started()
+{
+  thread_info_base* this_thread = thread_call_stack::contains(this);
+  ++static_cast<thread_info*>(this_thread)->private_outstanding_work;
+}
+
+void scheduler::post_immediate_completion(
+    scheduler::operation* op, bool is_continuation)
+{
+#if defined(ASIO_HAS_THREADS)
+  if (one_thread_ || is_continuation)
+  {
+    if (thread_info_base* this_thread = thread_call_stack::contains(this))
+    {
+      ++static_cast<thread_info*>(this_thread)->private_outstanding_work;
+      static_cast<thread_info*>(this_thread)->private_op_queue.push(op);
+      return;
+    }
+  }
+#else // defined(ASIO_HAS_THREADS)
+  (void)is_continuation;
+#endif // defined(ASIO_HAS_THREADS)
+
+  work_started();
+  mutex::scoped_lock lock(mutex_);
+  op_queue_.push(op);
+  wake_one_thread_and_unlock(lock);
+}
+
+void scheduler::post_deferred_completion(scheduler::operation* op)
+{
+#if defined(ASIO_HAS_THREADS)
+  if (one_thread_)
+  {
+    if (thread_info_base* this_thread = thread_call_stack::contains(this))
+    {
+      static_cast<thread_info*>(this_thread)->private_op_queue.push(op);
+      return;
+    }
+  }
+#endif // defined(ASIO_HAS_THREADS)
+
+  mutex::scoped_lock lock(mutex_);
+  op_queue_.push(op);
+  wake_one_thread_and_unlock(lock);
+}
+
+void scheduler::post_deferred_completions(
+    op_queue<scheduler::operation>& ops)
+{
+  if (!ops.empty())
+  {
+#if defined(ASIO_HAS_THREADS)
+    if (one_thread_)
+    {
+      if (thread_info_base* this_thread = thread_call_stack::contains(this))
+      {
+        static_cast<thread_info*>(this_thread)->private_op_queue.push(ops);
+        return;
+      }
+    }
+#endif // defined(ASIO_HAS_THREADS)
+
+    mutex::scoped_lock lock(mutex_);
+    op_queue_.push(ops);
+    wake_one_thread_and_unlock(lock);
+  }
+}
+
+void scheduler::do_dispatch(
+    scheduler::operation* op)
+{
+  work_started();
+  mutex::scoped_lock lock(mutex_);
+  op_queue_.push(op);
+  wake_one_thread_and_unlock(lock);
+}
+
+void scheduler::abandon_operations(
+    op_queue<scheduler::operation>& ops)
+{
+  op_queue<scheduler::operation> ops2;
+  ops2.push(ops);
+}
+
+std::size_t scheduler::do_run_one(mutex::scoped_lock& lock,
+    scheduler::thread_info& this_thread,
+    const asio::error_code& ec)
+{
+  while (!stopped_)
+  {
+    if (!op_queue_.empty())
+    {
+      // Prepare to execute first handler from queue.
+      operation* o = op_queue_.front();
+      op_queue_.pop();
+      bool more_handlers = (!op_queue_.empty());
+
+      if (o == &task_operation_)
+      {
+        task_interrupted_ = more_handlers;
+
+        if (more_handlers && !one_thread_)
+          wakeup_event_.unlock_and_signal_one(lock);
+        else
+          lock.unlock();
+
+        task_cleanup on_exit = { this, &lock, &this_thread };
+        (void)on_exit;
+
+        // Run the task. May throw an exception. Only block if the operation
+        // queue is empty and we're not polling, otherwise we want to return
+        // as soon as possible.
+        task_->run(more_handlers ? 0 : -1, this_thread.private_op_queue);
+      }
+      else
+      {
+        std::size_t task_result = o->task_result_;
+
+        if (more_handlers && !one_thread_)
+          wake_one_thread_and_unlock(lock);
+        else
+          lock.unlock();
+
+        // Ensure the count of outstanding work is decremented on block exit.
+        work_cleanup on_exit = { this, &lock, &this_thread };
+        (void)on_exit;
+
+        // Complete the operation. May throw an exception. Deletes the object.
+        o->complete(this, ec, task_result);
+
+        return 1;
+      }
+    }
+    else
+    {
+      wakeup_event_.clear(lock);
+      wakeup_event_.wait(lock);
+    }
+  }
+
+  return 0;
+}
+
+std::size_t scheduler::do_wait_one(mutex::scoped_lock& lock,
+    scheduler::thread_info& this_thread, long usec,
+    const asio::error_code& ec)
+{
+  if (stopped_)
+    return 0;
+
+  operation* o = op_queue_.front();
+  if (o == 0)
+  {
+    wakeup_event_.clear(lock);
+    wakeup_event_.wait_for_usec(lock, usec);
+    usec = 0; // Wait at most once.
+    o = op_queue_.front();
+  }
+
+  if (o == &task_operation_)
+  {
+    op_queue_.pop();
+    bool more_handlers = (!op_queue_.empty());
+
+    task_interrupted_ = more_handlers;
+
+    if (more_handlers && !one_thread_)
+      wakeup_event_.unlock_and_signal_one(lock);
+    else
+      lock.unlock();
+
+    {
+      task_cleanup on_exit = { this, &lock, &this_thread };
+      (void)on_exit;
+
+      // Run the task. May throw an exception. Only block if the operation
+      // queue is empty and we're not polling, otherwise we want to return
+      // as soon as possible.
+      task_->run(more_handlers ? 0 : usec, this_thread.private_op_queue);
+    }
+
+    o = op_queue_.front();
+    if (o == &task_operation_)
+    {
+      if (!one_thread_)
+        wakeup_event_.maybe_unlock_and_signal_one(lock);
+      return 0;
+    }
+  }
+
+  if (o == 0)
+    return 0;
+
+  op_queue_.pop();
+  bool more_handlers = (!op_queue_.empty());
+
+  std::size_t task_result = o->task_result_;
+
+  if (more_handlers && !one_thread_)
+    wake_one_thread_and_unlock(lock);
+  else
+    lock.unlock();
+
+  // Ensure the count of outstanding work is decremented on block exit.
+  work_cleanup on_exit = { this, &lock, &this_thread };
+  (void)on_exit;
+
+  // Complete the operation. May throw an exception. Deletes the object.
+  o->complete(this, ec, task_result);
+
+  return 1;
+}
+
+std::size_t scheduler::do_poll_one(mutex::scoped_lock& lock,
+    scheduler::thread_info& this_thread,
+    const asio::error_code& ec)
+{
+  if (stopped_)
+    return 0;
+
+  operation* o = op_queue_.front();
+  if (o == &task_operation_)
+  {
+    op_queue_.pop();
+    lock.unlock();
+
+    {
+      task_cleanup c = { this, &lock, &this_thread };
+      (void)c;
+
+      // Run the task. May throw an exception. Only block if the operation
+      // queue is empty and we're not polling, otherwise we want to return
+      // as soon as possible.
+      task_->run(0, this_thread.private_op_queue);
+    }
+
+    o = op_queue_.front();
+    if (o == &task_operation_)
+    {
+      wakeup_event_.maybe_unlock_and_signal_one(lock);
+      return 0;
+    }
+  }
+
+  if (o == 0)
+    return 0;
+
+  op_queue_.pop();
+  bool more_handlers = (!op_queue_.empty());
+
+  std::size_t task_result = o->task_result_;
+
+  if (more_handlers && !one_thread_)
+    wake_one_thread_and_unlock(lock);
+  else
+    lock.unlock();
+
+  // Ensure the count of outstanding work is decremented on block exit.
+  work_cleanup on_exit = { this, &lock, &this_thread };
+  (void)on_exit;
+
+  // Complete the operation. May throw an exception. Deletes the object.
+  o->complete(this, ec, task_result);
+
+  return 1;
+}
+
+void scheduler::stop_all_threads(
+    mutex::scoped_lock& lock)
+{
+  stopped_ = true;
+  wakeup_event_.signal_all(lock);
+
+  if (!task_interrupted_ && task_)
+  {
+    task_interrupted_ = true;
+    task_->interrupt();
+  }
+}
+
+void scheduler::wake_one_thread_and_unlock(
+    mutex::scoped_lock& lock)
+{
+  if (!wakeup_event_.maybe_unlock_and_signal_one(lock))
+  {
+    if (!task_interrupted_ && task_)
+    {
+      task_interrupted_ = true;
+      task_->interrupt();
+    }
+    lock.unlock();
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_SCHEDULER_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/select_reactor.hpp b/subprojects/asio/include/asio/detail/impl/select_reactor.hpp
new file mode 100644
index 000000000..04a04d49f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/select_reactor.hpp
@@ -0,0 +1,100 @@
+//
+// detail/impl/select_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SELECT_REACTOR_HPP
+#define ASIO_DETAIL_IMPL_SELECT_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP) \
+  || (!defined(ASIO_HAS_DEV_POLL) \
+      && !defined(ASIO_HAS_EPOLL) \
+      && !defined(ASIO_HAS_KQUEUE) \
+      && !defined(ASIO_WINDOWS_RUNTIME))
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+void select_reactor::add_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_add_timer_queue(queue);
+}
+
+// Remove a timer queue from the reactor.
+template <typename Time_Traits>
+void select_reactor::remove_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_remove_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void select_reactor::schedule_timer(timer_queue<Time_Traits>& queue,
+    const typename Time_Traits::time_type& time,
+    typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  if (shutdown_)
+  {
+    scheduler_.post_immediate_completion(op, false);
+    return;
+  }
+
+  bool earliest = queue.enqueue_timer(time, timer, op);
+  scheduler_.work_started();
+  if (earliest)
+    interrupter_.interrupt();
+}
+
+template <typename Time_Traits>
+std::size_t select_reactor::cancel_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& timer,
+    std::size_t max_cancelled)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  std::size_t n = queue.cancel_timer(timer, ops, max_cancelled);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+  return n;
+}
+
+template <typename Time_Traits>
+void select_reactor::move_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& target,
+    typename timer_queue<Time_Traits>::per_timer_data& source)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  queue.cancel_timer(target, ops);
+  queue.move_timer(target, source);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+       //   || (!defined(ASIO_HAS_DEV_POLL)
+       //       && !defined(ASIO_HAS_EPOLL)
+       //       && !defined(ASIO_HAS_KQUEUE)
+       //       && !defined(ASIO_WINDOWS_RUNTIME))
+
+#endif // ASIO_DETAIL_IMPL_SELECT_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/select_reactor.ipp b/subprojects/asio/include/asio/detail/impl/select_reactor.ipp
new file mode 100644
index 000000000..262bc6980
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/select_reactor.ipp
@@ -0,0 +1,333 @@
+//
+// detail/impl/select_reactor.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SELECT_REACTOR_IPP
+#define ASIO_DETAIL_IMPL_SELECT_REACTOR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP) \
+  || (!defined(ASIO_HAS_DEV_POLL) \
+      && !defined(ASIO_HAS_EPOLL) \
+      && !defined(ASIO_HAS_KQUEUE) \
+      && !defined(ASIO_WINDOWS_RUNTIME))
+
+#include "asio/detail/fd_set_adapter.hpp"
+#include "asio/detail/select_reactor.hpp"
+#include "asio/detail/signal_blocker.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_IOCP)
+class select_reactor::thread_function
+{
+public:
+  explicit thread_function(select_reactor* r)
+    : this_(r)
+  {
+  }
+
+  void operator()()
+  {
+    this_->run_thread();
+  }
+
+private:
+  select_reactor* this_;
+};
+#endif // defined(ASIO_HAS_IOCP)
+
+select_reactor::select_reactor(asio::execution_context& ctx)
+  : execution_context_service_base<select_reactor>(ctx),
+    scheduler_(use_service<scheduler_type>(ctx)),
+    mutex_(),
+    interrupter_(),
+#if defined(ASIO_HAS_IOCP)
+    stop_thread_(false),
+    thread_(0),
+#endif // defined(ASIO_HAS_IOCP)
+    shutdown_(false)
+{
+#if defined(ASIO_HAS_IOCP)
+  asio::detail::signal_blocker sb;
+  thread_ = new asio::detail::thread(thread_function(this));
+#endif // defined(ASIO_HAS_IOCP)
+}
+
+select_reactor::~select_reactor()
+{
+  shutdown();
+}
+
+void select_reactor::shutdown()
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  shutdown_ = true;
+#if defined(ASIO_HAS_IOCP)
+  stop_thread_ = true;
+#endif // defined(ASIO_HAS_IOCP)
+  lock.unlock();
+
+#if defined(ASIO_HAS_IOCP)
+  if (thread_)
+  {
+    interrupter_.interrupt();
+    thread_->join();
+    delete thread_;
+    thread_ = 0;
+  }
+#endif // defined(ASIO_HAS_IOCP)
+
+  op_queue<operation> ops;
+
+  for (int i = 0; i < max_ops; ++i)
+    op_queue_[i].get_all_operations(ops);
+
+  timer_queues_.get_all_timers(ops);
+
+  scheduler_.abandon_operations(ops);
+}
+
+void select_reactor::notify_fork(
+    asio::execution_context::fork_event fork_ev)
+{
+  if (fork_ev == asio::execution_context::fork_child)
+    interrupter_.recreate();
+}
+
+void select_reactor::init_task()
+{
+  scheduler_.init_task();
+}
+
+int select_reactor::register_descriptor(socket_type,
+    select_reactor::per_descriptor_data&)
+{
+  return 0;
+}
+
+int select_reactor::register_internal_descriptor(
+    int op_type, socket_type descriptor,
+    select_reactor::per_descriptor_data&, reactor_op* op)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  op_queue_[op_type].enqueue_operation(descriptor, op);
+  interrupter_.interrupt();
+
+  return 0;
+}
+
+void select_reactor::move_descriptor(socket_type,
+    select_reactor::per_descriptor_data&,
+    select_reactor::per_descriptor_data&)
+{
+}
+
+void select_reactor::start_op(int op_type, socket_type descriptor,
+    select_reactor::per_descriptor_data&, reactor_op* op,
+    bool is_continuation, bool)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  if (shutdown_)
+  {
+    post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  bool first = op_queue_[op_type].enqueue_operation(descriptor, op);
+  scheduler_.work_started();
+  if (first)
+    interrupter_.interrupt();
+}
+
+void select_reactor::cancel_ops(socket_type descriptor,
+    select_reactor::per_descriptor_data&)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  cancel_ops_unlocked(descriptor, asio::error::operation_aborted);
+}
+
+void select_reactor::deregister_descriptor(socket_type descriptor,
+    select_reactor::per_descriptor_data&, bool)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  cancel_ops_unlocked(descriptor, asio::error::operation_aborted);
+}
+
+void select_reactor::deregister_internal_descriptor(
+    socket_type descriptor, select_reactor::per_descriptor_data&)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  for (int i = 0; i < max_ops; ++i)
+    op_queue_[i].cancel_operations(descriptor, ops);
+}
+
+void select_reactor::cleanup_descriptor_data(
+    select_reactor::per_descriptor_data&)
+{
+}
+
+void select_reactor::run(long usec, op_queue<operation>& ops)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+#if defined(ASIO_HAS_IOCP)
+  // Check if the thread is supposed to stop.
+  if (stop_thread_)
+    return;
+#endif // defined(ASIO_HAS_IOCP)
+
+  // Set up the descriptor sets.
+  for (int i = 0; i < max_select_ops; ++i)
+    fd_sets_[i].reset();
+  fd_sets_[read_op].set(interrupter_.read_descriptor());
+  socket_type max_fd = 0;
+  bool have_work_to_do = !timer_queues_.all_empty();
+  for (int i = 0; i < max_select_ops; ++i)
+  {
+    have_work_to_do = have_work_to_do || !op_queue_[i].empty();
+    fd_sets_[i].set(op_queue_[i], ops);
+    if (fd_sets_[i].max_descriptor() > max_fd)
+      max_fd = fd_sets_[i].max_descriptor();
+  }
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  // Connection operations on Windows use both except and write fd_sets.
+  have_work_to_do = have_work_to_do || !op_queue_[connect_op].empty();
+  fd_sets_[write_op].set(op_queue_[connect_op], ops);
+  if (fd_sets_[write_op].max_descriptor() > max_fd)
+    max_fd = fd_sets_[write_op].max_descriptor();
+  fd_sets_[except_op].set(op_queue_[connect_op], ops);
+  if (fd_sets_[except_op].max_descriptor() > max_fd)
+    max_fd = fd_sets_[except_op].max_descriptor();
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+  // We can return immediately if there's no work to do and the reactor is
+  // not supposed to block.
+  if (!usec && !have_work_to_do)
+    return;
+
+  // Determine how long to block while waiting for events.
+  timeval tv_buf = { 0, 0 };
+  timeval* tv = usec ? get_timeout(usec, tv_buf) : &tv_buf;
+
+  lock.unlock();
+
+  // Block on the select call until descriptors become ready.
+  asio::error_code ec;
+  int retval = socket_ops::select(static_cast<int>(max_fd + 1),
+      fd_sets_[read_op], fd_sets_[write_op], fd_sets_[except_op], tv, ec);
+
+  // Reset the interrupter.
+  if (retval > 0 && fd_sets_[read_op].is_set(interrupter_.read_descriptor()))
+  {
+    interrupter_.reset();
+    --retval;
+  }
+
+  lock.lock();
+
+  // Dispatch all ready operations.
+  if (retval > 0)
+  {
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    // Connection operations on Windows use both except and write fd_sets.
+    fd_sets_[except_op].perform(op_queue_[connect_op], ops);
+    fd_sets_[write_op].perform(op_queue_[connect_op], ops);
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+    // Exception operations must be processed first to ensure that any
+    // out-of-band data is read before normal data.
+    for (int i = max_select_ops - 1; i >= 0; --i)
+      fd_sets_[i].perform(op_queue_[i], ops);
+  }
+  timer_queues_.get_ready_timers(ops);
+}
+
+void select_reactor::interrupt()
+{
+  interrupter_.interrupt();
+}
+
+#if defined(ASIO_HAS_IOCP)
+void select_reactor::run_thread()
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  while (!stop_thread_)
+  {
+    lock.unlock();
+    op_queue<operation> ops;
+    run(true, ops);
+    scheduler_.post_deferred_completions(ops);
+    lock.lock();
+  }
+}
+#endif // defined(ASIO_HAS_IOCP)
+
+void select_reactor::do_add_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.insert(&queue);
+}
+
+void select_reactor::do_remove_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.erase(&queue);
+}
+
+timeval* select_reactor::get_timeout(long usec, timeval& tv)
+{
+  // By default we will wait no longer than 5 minutes. This will ensure that
+  // any changes to the system clock are detected after no longer than this.
+  const long max_usec = 5 * 60 * 1000 * 1000;
+  usec = timer_queues_.wait_duration_usec(
+      (usec < 0 || max_usec < usec) ? max_usec : usec);
+  tv.tv_sec = usec / 1000000;
+  tv.tv_usec = usec % 1000000;
+  return &tv;
+}
+
+void select_reactor::cancel_ops_unlocked(socket_type descriptor,
+    const asio::error_code& ec)
+{
+  bool need_interrupt = false;
+  op_queue<operation> ops;
+  for (int i = 0; i < max_ops; ++i)
+    need_interrupt = op_queue_[i].cancel_operations(
+        descriptor, ops, ec) || need_interrupt;
+  scheduler_.post_deferred_completions(ops);
+  if (need_interrupt)
+    interrupter_.interrupt();
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+       //   || (!defined(ASIO_HAS_DEV_POLL)
+       //       && !defined(ASIO_HAS_EPOLL)
+       //       && !defined(ASIO_HAS_KQUEUE))
+       //       && !defined(ASIO_WINDOWS_RUNTIME))
+
+#endif // ASIO_DETAIL_IMPL_SELECT_REACTOR_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/service_registry.hpp b/subprojects/asio/include/asio/detail/impl/service_registry.hpp
new file mode 100644
index 000000000..d4db58994
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/service_registry.hpp
@@ -0,0 +1,94 @@
+//
+// detail/impl/service_registry.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SERVICE_REGISTRY_HPP
+#define ASIO_DETAIL_IMPL_SERVICE_REGISTRY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Service>
+Service& service_registry::use_service()
+{
+  execution_context::service::key key;
+  init_key<Service>(key, 0);
+  factory_type factory = &service_registry::create<Service, execution_context>;
+  return *static_cast<Service*>(do_use_service(key, factory, &owner_));
+}
+
+template <typename Service>
+Service& service_registry::use_service(io_context& owner)
+{
+  execution_context::service::key key;
+  init_key<Service>(key, 0);
+  factory_type factory = &service_registry::create<Service, io_context>;
+  return *static_cast<Service*>(do_use_service(key, factory, &owner));
+}
+
+template <typename Service>
+void service_registry::add_service(Service* new_service)
+{
+  execution_context::service::key key;
+  init_key<Service>(key, 0);
+  return do_add_service(key, new_service);
+}
+
+template <typename Service>
+bool service_registry::has_service() const
+{
+  execution_context::service::key key;
+  init_key<Service>(key, 0);
+  return do_has_service(key);
+}
+
+template <typename Service>
+inline void service_registry::init_key(
+    execution_context::service::key& key, ...)
+{
+  init_key_from_id(key, Service::id);
+}
+
+#if !defined(ASIO_NO_TYPEID)
+template <typename Service>
+void service_registry::init_key(execution_context::service::key& key,
+    typename enable_if<
+      is_base_of<typename Service::key_type, Service>::value>::type*)
+{
+  key.type_info_ = &typeid(typeid_wrapper<Service>);
+  key.id_ = 0;
+}
+
+template <typename Service>
+void service_registry::init_key_from_id(execution_context::service::key& key,
+    const service_id<Service>& /*id*/)
+{
+  key.type_info_ = &typeid(typeid_wrapper<Service>);
+  key.id_ = 0;
+}
+#endif // !defined(ASIO_NO_TYPEID)
+
+template <typename Service, typename Owner>
+execution_context::service* service_registry::create(void* owner)
+{
+  return new Service(*static_cast<Owner*>(owner));
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_SERVICE_REGISTRY_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/service_registry.ipp b/subprojects/asio/include/asio/detail/impl/service_registry.ipp
new file mode 100644
index 000000000..a46503321
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/service_registry.ipp
@@ -0,0 +1,197 @@
+//
+// detail/impl/service_registry.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SERVICE_REGISTRY_IPP
+#define ASIO_DETAIL_IMPL_SERVICE_REGISTRY_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <vector>
+#include "asio/detail/service_registry.hpp"
+#include "asio/detail/throw_exception.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+service_registry::service_registry(execution_context& owner)
+  : owner_(owner),
+    first_service_(0)
+{
+}
+
+service_registry::~service_registry()
+{
+}
+
+void service_registry::shutdown_services()
+{
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    service->shutdown();
+    service = service->next_;
+  }
+}
+
+void service_registry::destroy_services()
+{
+  while (first_service_)
+  {
+    execution_context::service* next_service = first_service_->next_;
+    destroy(first_service_);
+    first_service_ = next_service;
+  }
+}
+
+void service_registry::notify_fork(execution_context::fork_event fork_ev)
+{
+  // Make a copy of all of the services while holding the lock. We don't want
+  // to hold the lock while calling into each service, as it may try to call
+  // back into this class.
+  std::vector<execution_context::service*> services;
+  {
+    asio::detail::mutex::scoped_lock lock(mutex_);
+    execution_context::service* service = first_service_;
+    while (service)
+    {
+      services.push_back(service);
+      service = service->next_;
+    }
+  }
+
+  // If processing the fork_prepare event, we want to go in reverse order of
+  // service registration, which happens to be the existing order of the
+  // services in the vector. For the other events we want to go in the other
+  // direction.
+  std::size_t num_services = services.size();
+  if (fork_ev == execution_context::fork_prepare)
+    for (std::size_t i = 0; i < num_services; ++i)
+      services[i]->notify_fork(fork_ev);
+  else
+    for (std::size_t i = num_services; i > 0; --i)
+      services[i - 1]->notify_fork(fork_ev);
+}
+
+void service_registry::init_key_from_id(execution_context::service::key& key,
+    const execution_context::id& id)
+{
+  key.type_info_ = 0;
+  key.id_ = &id;
+}
+
+bool service_registry::keys_match(
+    const execution_context::service::key& key1,
+    const execution_context::service::key& key2)
+{
+  if (key1.id_ && key2.id_)
+    if (key1.id_ == key2.id_)
+      return true;
+  if (key1.type_info_ && key2.type_info_)
+    if (*key1.type_info_ == *key2.type_info_)
+      return true;
+  return false;
+}
+
+void service_registry::destroy(execution_context::service* service)
+{
+  delete service;
+}
+
+execution_context::service* service_registry::do_use_service(
+    const execution_context::service::key& key,
+    factory_type factory, void* owner)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // First see if there is an existing service object with the given key.
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      return service;
+    service = service->next_;
+  }
+
+  // Create a new service object. The service registry's mutex is not locked
+  // at this time to allow for nested calls into this function from the new
+  // service's constructor.
+  lock.unlock();
+  auto_service_ptr new_service = { factory(owner) };
+  new_service.ptr_->key_ = key;
+  lock.lock();
+
+  // Check that nobody else created another service object of the same type
+  // while the lock was released.
+  service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      return service;
+    service = service->next_;
+  }
+
+  // Service was successfully initialised, pass ownership to registry.
+  new_service.ptr_->next_ = first_service_;
+  first_service_ = new_service.ptr_;
+  new_service.ptr_ = 0;
+  return first_service_;
+}
+
+void service_registry::do_add_service(
+    const execution_context::service::key& key,
+    execution_context::service* new_service)
+{
+  if (&owner_ != &new_service->context())
+    asio::detail::throw_exception(invalid_service_owner());
+
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // Check if there is an existing service object with the given key.
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      asio::detail::throw_exception(service_already_exists());
+    service = service->next_;
+  }
+
+  // Take ownership of the service object.
+  new_service->key_ = key;
+  new_service->next_ = first_service_;
+  first_service_ = new_service;
+}
+
+bool service_registry::do_has_service(
+    const execution_context::service::key& key) const
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      return true;
+    service = service->next_;
+  }
+
+  return false;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_SERVICE_REGISTRY_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/signal_set_service.ipp b/subprojects/asio/include/asio/detail/impl/signal_set_service.ipp
new file mode 100644
index 000000000..dd68fc152
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/signal_set_service.ipp
@@ -0,0 +1,669 @@
+//
+// detail/impl/signal_set_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SIGNAL_SET_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_SIGNAL_SET_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cstring>
+#include <stdexcept>
+#include "asio/detail/reactor.hpp"
+#include "asio/detail/signal_blocker.hpp"
+#include "asio/detail/signal_set_service.hpp"
+#include "asio/detail/static_mutex.hpp"
+#include "asio/detail/throw_exception.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct signal_state
+{
+  // Mutex used for protecting global state.
+  static_mutex mutex_;
+
+  // The read end of the pipe used for signal notifications.
+  int read_descriptor_;
+
+  // The write end of the pipe used for signal notifications.
+  int write_descriptor_;
+
+  // Whether the signal state has been prepared for a fork.
+  bool fork_prepared_;
+
+  // The head of a linked list of all signal_set_service instances.
+  class signal_set_service* service_list_;
+
+  // A count of the number of objects that are registered for each signal.
+  std::size_t registration_count_[max_signal_number];
+};
+
+signal_state* get_signal_state()
+{
+  static signal_state state = {
+    ASIO_STATIC_MUTEX_INIT, -1, -1, false, 0, { 0 } };
+  return &state;
+}
+
+void asio_signal_handler(int signal_number)
+{
+#if defined(ASIO_WINDOWS) \
+  || defined(ASIO_WINDOWS_RUNTIME) \
+  || defined(__CYGWIN__)
+  signal_set_service::deliver_signal(signal_number);
+#else // defined(ASIO_WINDOWS)
+      //   || defined(ASIO_WINDOWS_RUNTIME)
+      //   || defined(__CYGWIN__)
+  int saved_errno = errno;
+  signal_state* state = get_signal_state();
+  signed_size_type result = ::write(state->write_descriptor_,
+      &signal_number, sizeof(signal_number));
+  (void)result;
+  errno = saved_errno;
+#endif // defined(ASIO_WINDOWS)
+       //   || defined(ASIO_WINDOWS_RUNTIME)
+       //   || defined(__CYGWIN__)
+
+#if defined(ASIO_HAS_SIGNAL) && !defined(ASIO_HAS_SIGACTION)
+  ::signal(signal_number, asio_signal_handler);
+#endif // defined(ASIO_HAS_SIGNAL) && !defined(ASIO_HAS_SIGACTION)
+}
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+class signal_set_service::pipe_read_op : public reactor_op
+{
+public:
+  pipe_read_op()
+    : reactor_op(&pipe_read_op::do_perform, pipe_read_op::do_complete)
+  {
+  }
+
+  static status do_perform(reactor_op*)
+  {
+    signal_state* state = get_signal_state();
+
+    int fd = state->read_descriptor_;
+    int signal_number = 0;
+    while (::read(fd, &signal_number, sizeof(int)) == sizeof(int))
+      if (signal_number >= 0 && signal_number < max_signal_number)
+        signal_set_service::deliver_signal(signal_number);
+
+    return not_done;
+  }
+
+  static void do_complete(void* /*owner*/, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    pipe_read_op* o(static_cast<pipe_read_op*>(base));
+    delete o;
+  }
+};
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+signal_set_service::signal_set_service(
+    asio::io_context& io_context)
+  : service_base<signal_set_service>(io_context),
+    io_context_(asio::use_service<io_context_impl>(io_context)),
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+    reactor_(asio::use_service<reactor>(io_context)),
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+    next_(0),
+    prev_(0)
+{
+  get_signal_state()->mutex_.init();
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+  reactor_.init_task();
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+  for (int i = 0; i < max_signal_number; ++i)
+    registrations_[i] = 0;
+
+  add_service(this);
+}
+
+signal_set_service::~signal_set_service()
+{
+  remove_service(this);
+}
+
+void signal_set_service::shutdown()
+{
+  remove_service(this);
+
+  op_queue<operation> ops;
+
+  for (int i = 0; i < max_signal_number; ++i)
+  {
+    registration* reg = registrations_[i];
+    while (reg)
+    {
+      ops.push(*reg->queue_);
+      reg = reg->next_in_table_;
+    }
+  }
+
+  io_context_.abandon_operations(ops);
+}
+
+void signal_set_service::notify_fork(
+    asio::io_context::fork_event fork_ev)
+{
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+  switch (fork_ev)
+  {
+  case asio::io_context::fork_prepare:
+    {
+      int read_descriptor = state->read_descriptor_;
+      state->fork_prepared_ = true;
+      lock.unlock();
+      reactor_.deregister_internal_descriptor(read_descriptor, reactor_data_);
+      reactor_.cleanup_descriptor_data(reactor_data_);
+    }
+    break;
+  case asio::io_context::fork_parent:
+    if (state->fork_prepared_)
+    {
+      int read_descriptor = state->read_descriptor_;
+      state->fork_prepared_ = false;
+      lock.unlock();
+      reactor_.register_internal_descriptor(reactor::read_op,
+          read_descriptor, reactor_data_, new pipe_read_op);
+    }
+    break;
+  case asio::io_context::fork_child:
+    if (state->fork_prepared_)
+    {
+      asio::detail::signal_blocker blocker;
+      close_descriptors();
+      open_descriptors();
+      int read_descriptor = state->read_descriptor_;
+      state->fork_prepared_ = false;
+      lock.unlock();
+      reactor_.register_internal_descriptor(reactor::read_op,
+          read_descriptor, reactor_data_, new pipe_read_op);
+    }
+    break;
+  default:
+    break;
+  }
+#else // !defined(ASIO_WINDOWS)
+      //   && !defined(ASIO_WINDOWS_RUNTIME)
+      //   && !defined(__CYGWIN__)
+  (void)fork_ev;
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+}
+
+void signal_set_service::construct(
+    signal_set_service::implementation_type& impl)
+{
+  impl.signals_ = 0;
+}
+
+void signal_set_service::destroy(
+    signal_set_service::implementation_type& impl)
+{
+  asio::error_code ignored_ec;
+  clear(impl, ignored_ec);
+  cancel(impl, ignored_ec);
+}
+
+asio::error_code signal_set_service::add(
+    signal_set_service::implementation_type& impl,
+    int signal_number, asio::error_code& ec)
+{
+  // Check that the signal number is valid.
+  if (signal_number < 0 || signal_number >= max_signal_number)
+  {
+    ec = asio::error::invalid_argument;
+    return ec;
+  }
+
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+  // Find the appropriate place to insert the registration.
+  registration** insertion_point = &impl.signals_;
+  registration* next = impl.signals_;
+  while (next && next->signal_number_ < signal_number)
+  {
+    insertion_point = &next->next_in_set_;
+    next = next->next_in_set_;
+  }
+
+  // Only do something if the signal is not already registered.
+  if (next == 0 || next->signal_number_ != signal_number)
+  {
+    registration* new_registration = new registration;
+
+#if defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)
+    // Register for the signal if we're the first.
+    if (state->registration_count_[signal_number] == 0)
+    {
+# if defined(ASIO_HAS_SIGACTION)
+      using namespace std; // For memset.
+      struct sigaction sa;
+      memset(&sa, 0, sizeof(sa));
+      sa.sa_handler = asio_signal_handler;
+      sigfillset(&sa.sa_mask);
+      if (::sigaction(signal_number, &sa, 0) == -1)
+# else // defined(ASIO_HAS_SIGACTION)
+      if (::signal(signal_number, asio_signal_handler) == SIG_ERR)
+# endif // defined(ASIO_HAS_SIGACTION)
+      {
+# if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        ec = asio::error::invalid_argument;
+# else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        ec = asio::error_code(errno,
+            asio::error::get_system_category());
+# endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        delete new_registration;
+        return ec;
+      }
+    }
+#endif // defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)
+
+    // Record the new registration in the set.
+    new_registration->signal_number_ = signal_number;
+    new_registration->queue_ = &impl.queue_;
+    new_registration->next_in_set_ = next;
+    *insertion_point = new_registration;
+
+    // Insert registration into the registration table.
+    new_registration->next_in_table_ = registrations_[signal_number];
+    if (registrations_[signal_number])
+      registrations_[signal_number]->prev_in_table_ = new_registration;
+    registrations_[signal_number] = new_registration;
+
+    ++state->registration_count_[signal_number];
+  }
+
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code signal_set_service::remove(
+    signal_set_service::implementation_type& impl,
+    int signal_number, asio::error_code& ec)
+{
+  // Check that the signal number is valid.
+  if (signal_number < 0 || signal_number >= max_signal_number)
+  {
+    ec = asio::error::invalid_argument;
+    return ec;
+  }
+
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+  // Find the signal number in the list of registrations.
+  registration** deletion_point = &impl.signals_;
+  registration* reg = impl.signals_;
+  while (reg && reg->signal_number_ < signal_number)
+  {
+    deletion_point = &reg->next_in_set_;
+    reg = reg->next_in_set_;
+  }
+
+  if (reg != 0 && reg->signal_number_ == signal_number)
+  {
+#if defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)
+    // Set signal handler back to the default if we're the last.
+    if (state->registration_count_[signal_number] == 1)
+    {
+# if defined(ASIO_HAS_SIGACTION)
+      using namespace std; // For memset.
+      struct sigaction sa;
+      memset(&sa, 0, sizeof(sa));
+      sa.sa_handler = SIG_DFL;
+      if (::sigaction(signal_number, &sa, 0) == -1)
+# else // defined(ASIO_HAS_SIGACTION)
+      if (::signal(signal_number, SIG_DFL) == SIG_ERR)
+# endif // defined(ASIO_HAS_SIGACTION)
+      {
+# if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        ec = asio::error::invalid_argument;
+# else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        ec = asio::error_code(errno,
+            asio::error::get_system_category());
+# endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        return ec;
+      }
+    }
+#endif // defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)
+
+    // Remove the registration from the set.
+    *deletion_point = reg->next_in_set_;
+
+    // Remove the registration from the registration table.
+    if (registrations_[signal_number] == reg)
+      registrations_[signal_number] = reg->next_in_table_;
+    if (reg->prev_in_table_)
+      reg->prev_in_table_->next_in_table_ = reg->next_in_table_;
+    if (reg->next_in_table_)
+      reg->next_in_table_->prev_in_table_ = reg->prev_in_table_;
+
+    --state->registration_count_[signal_number];
+
+    delete reg;
+  }
+
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code signal_set_service::clear(
+    signal_set_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+  while (registration* reg = impl.signals_)
+  {
+#if defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)
+    // Set signal handler back to the default if we're the last.
+    if (state->registration_count_[reg->signal_number_] == 1)
+    {
+# if defined(ASIO_HAS_SIGACTION)
+      using namespace std; // For memset.
+      struct sigaction sa;
+      memset(&sa, 0, sizeof(sa));
+      sa.sa_handler = SIG_DFL;
+      if (::sigaction(reg->signal_number_, &sa, 0) == -1)
+# else // defined(ASIO_HAS_SIGACTION)
+      if (::signal(reg->signal_number_, SIG_DFL) == SIG_ERR)
+# endif // defined(ASIO_HAS_SIGACTION)
+      {
+# if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        ec = asio::error::invalid_argument;
+# else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        ec = asio::error_code(errno,
+            asio::error::get_system_category());
+# endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+        return ec;
+      }
+    }
+#endif // defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)
+
+    // Remove the registration from the registration table.
+    if (registrations_[reg->signal_number_] == reg)
+      registrations_[reg->signal_number_] = reg->next_in_table_;
+    if (reg->prev_in_table_)
+      reg->prev_in_table_->next_in_table_ = reg->next_in_table_;
+    if (reg->next_in_table_)
+      reg->next_in_table_->prev_in_table_ = reg->prev_in_table_;
+
+    --state->registration_count_[reg->signal_number_];
+
+    impl.signals_ = reg->next_in_set_;
+    delete reg;
+  }
+
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code signal_set_service::cancel(
+    signal_set_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  ASIO_HANDLER_OPERATION((io_context_.context(),
+        "signal_set", &impl, 0, "cancel"));
+
+  op_queue<operation> ops;
+  {
+    signal_state* state = get_signal_state();
+    static_mutex::scoped_lock lock(state->mutex_);
+
+    while (signal_op* op = impl.queue_.front())
+    {
+      op->ec_ = asio::error::operation_aborted;
+      impl.queue_.pop();
+      ops.push(op);
+    }
+  }
+
+  io_context_.post_deferred_completions(ops);
+
+  ec = asio::error_code();
+  return ec;
+}
+
+void signal_set_service::deliver_signal(int signal_number)
+{
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+  signal_set_service* service = state->service_list_;
+  while (service)
+  {
+    op_queue<operation> ops;
+
+    registration* reg = service->registrations_[signal_number];
+    while (reg)
+    {
+      if (reg->queue_->empty())
+      {
+        ++reg->undelivered_;
+      }
+      else
+      {
+        while (signal_op* op = reg->queue_->front())
+        {
+          op->signal_number_ = signal_number;
+          reg->queue_->pop();
+          ops.push(op);
+        }
+      }
+
+      reg = reg->next_in_table_;
+    }
+
+    service->io_context_.post_deferred_completions(ops);
+
+    service = service->next_;
+  }
+}
+
+void signal_set_service::add_service(signal_set_service* service)
+{
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+  // If this is the first service to be created, open a new pipe.
+  if (state->service_list_ == 0)
+    open_descriptors();
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+  // If an io_context object is thread-unsafe then it must be the only
+  // io_context used to create signal_set objects.
+  if (state->service_list_ != 0)
+  {
+    if (!ASIO_CONCURRENCY_HINT_IS_LOCKING(SCHEDULER,
+          service->io_context_.concurrency_hint())
+        || !ASIO_CONCURRENCY_HINT_IS_LOCKING(SCHEDULER,
+          state->service_list_->io_context_.concurrency_hint()))
+    {
+      std::logic_error ex(
+          "Thread-unsafe io_context objects require "
+          "exclusive access to signal handling.");
+      asio::detail::throw_exception(ex);
+    }
+  }
+
+  // Insert service into linked list of all services.
+  service->next_ = state->service_list_;
+  service->prev_ = 0;
+  if (state->service_list_)
+    state->service_list_->prev_ = service;
+  state->service_list_ = service;
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+  // Register for pipe readiness notifications.
+  int read_descriptor = state->read_descriptor_;
+  lock.unlock();
+  service->reactor_.register_internal_descriptor(reactor::read_op,
+      read_descriptor, service->reactor_data_, new pipe_read_op);
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+}
+
+void signal_set_service::remove_service(signal_set_service* service)
+{
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+  if (service->next_ || service->prev_ || state->service_list_ == service)
+  {
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+    // Disable the pipe readiness notifications.
+    int read_descriptor = state->read_descriptor_;
+    lock.unlock();
+    service->reactor_.deregister_internal_descriptor(
+        read_descriptor, service->reactor_data_);
+    service->reactor_.cleanup_descriptor_data(service->reactor_data_);
+    lock.lock();
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+    // Remove service from linked list of all services.
+    if (state->service_list_ == service)
+      state->service_list_ = service->next_;
+    if (service->prev_)
+      service->prev_->next_ = service->next_;
+    if (service->next_)
+      service->next_->prev_= service->prev_;
+    service->next_ = 0;
+    service->prev_ = 0;
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+    // If this is the last service to be removed, close the pipe.
+    if (state->service_list_ == 0)
+      close_descriptors();
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+  }
+}
+
+void signal_set_service::open_descriptors()
+{
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+  signal_state* state = get_signal_state();
+
+  int pipe_fds[2];
+  if (::pipe(pipe_fds) == 0)
+  {
+    state->read_descriptor_ = pipe_fds[0];
+    ::fcntl(state->read_descriptor_, F_SETFL, O_NONBLOCK);
+
+    state->write_descriptor_ = pipe_fds[1];
+    ::fcntl(state->write_descriptor_, F_SETFL, O_NONBLOCK);
+
+#if defined(FD_CLOEXEC)
+    ::fcntl(state->read_descriptor_, F_SETFD, FD_CLOEXEC);
+    ::fcntl(state->write_descriptor_, F_SETFD, FD_CLOEXEC);
+#endif // defined(FD_CLOEXEC)
+  }
+  else
+  {
+    asio::error_code ec(errno,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "signal_set_service pipe");
+  }
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+}
+
+void signal_set_service::close_descriptors()
+{
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+  signal_state* state = get_signal_state();
+
+  if (state->read_descriptor_ != -1)
+    ::close(state->read_descriptor_);
+  state->read_descriptor_ = -1;
+
+  if (state->write_descriptor_ != -1)
+    ::close(state->write_descriptor_);
+  state->write_descriptor_ = -1;
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+}
+
+void signal_set_service::start_wait_op(
+    signal_set_service::implementation_type& impl, signal_op* op)
+{
+  io_context_.work_started();
+
+  signal_state* state = get_signal_state();
+  static_mutex::scoped_lock lock(state->mutex_);
+
+  registration* reg = impl.signals_;
+  while (reg)
+  {
+    if (reg->undelivered_ > 0)
+    {
+      --reg->undelivered_;
+      op->signal_number_ = reg->signal_number_;
+      io_context_.post_deferred_completion(op);
+      return;
+    }
+
+    reg = reg->next_in_set_;
+  }
+
+  impl.queue_.push(op);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_SIGNAL_SET_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/socket_ops.ipp b/subprojects/asio/include/asio/detail/impl/socket_ops.ipp
new file mode 100644
index 000000000..7df3400f7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/socket_ops.ipp
@@ -0,0 +1,3571 @@
+//
+// detail/impl/socket_ops.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SOCKET_OPS_IPP
+#define ASIO_DETAIL_SOCKET_OPS_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <cerrno>
+#include <new>
+#include "asio/detail/assert.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include <codecvt>
+# include <locale>
+# include <string>
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__) \
+  || defined(__MACH__) && defined(__APPLE__)
+# if defined(ASIO_HAS_PTHREADS)
+#  include <pthread.h>
+# endif // defined(ASIO_HAS_PTHREADS)
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+       // || defined(__MACH__) && defined(__APPLE__)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace socket_ops {
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+struct msghdr { int msg_namelen; };
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#if defined(__hpux)
+// HP-UX doesn't declare these functions extern "C", so they are declared again
+// here to avoid linker errors about undefined symbols.
+extern "C" char* if_indextoname(unsigned int, char*);
+extern "C" unsigned int if_nametoindex(const char*);
+#endif // defined(__hpux)
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+inline void clear_last_error()
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  WSASetLastError(0);
+#else
+  errno = 0;
+#endif
+}
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+template <typename ReturnType>
+inline ReturnType error_wrapper(ReturnType return_value,
+    asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  ec = asio::error_code(WSAGetLastError(),
+      asio::error::get_system_category());
+#else
+  ec = asio::error_code(errno,
+      asio::error::get_system_category());
+#endif
+  return return_value;
+}
+
+template <typename SockLenType>
+inline socket_type call_accept(SockLenType msghdr::*,
+    socket_type s, socket_addr_type* addr, std::size_t* addrlen)
+{
+  SockLenType tmp_addrlen = addrlen ? (SockLenType)*addrlen : 0;
+  socket_type result = ::accept(s, addr, addrlen ? &tmp_addrlen : 0);
+  if (addrlen)
+    *addrlen = (std::size_t)tmp_addrlen;
+  return result;
+}
+
+socket_type accept(socket_type s, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return invalid_socket;
+  }
+
+  clear_last_error();
+
+  socket_type new_s = error_wrapper(call_accept(
+        &msghdr::msg_namelen, s, addr, addrlen), ec);
+  if (new_s == invalid_socket)
+    return new_s;
+
+#if defined(__MACH__) && defined(__APPLE__) || defined(__FreeBSD__)
+  int optval = 1;
+  int result = error_wrapper(::setsockopt(new_s,
+        SOL_SOCKET, SO_NOSIGPIPE, &optval, sizeof(optval)), ec);
+  if (result != 0)
+  {
+    ::close(new_s);
+    return invalid_socket;
+  }
+#endif
+
+  ec = asio::error_code();
+  return new_s;
+}
+
+socket_type sync_accept(socket_type s, state_type state,
+    socket_addr_type* addr, std::size_t* addrlen, asio::error_code& ec)
+{
+  // Accept a socket.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    socket_type new_socket = socket_ops::accept(s, addr, addrlen, ec);
+
+    // Check if operation succeeded.
+    if (new_socket != invalid_socket)
+      return new_socket;
+
+    // Operation failed.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+    {
+      if (state & user_set_non_blocking)
+        return invalid_socket;
+      // Fall through to retry operation.
+    }
+    else if (ec == asio::error::connection_aborted)
+    {
+      if (state & enable_connection_aborted)
+        return invalid_socket;
+      // Fall through to retry operation.
+    }
+#if defined(EPROTO)
+    else if (ec.value() == EPROTO)
+    {
+      if (state & enable_connection_aborted)
+        return invalid_socket;
+      // Fall through to retry operation.
+    }
+#endif // defined(EPROTO)
+    else
+      return invalid_socket;
+
+    // Wait for socket to become ready.
+    if (socket_ops::poll_read(s, 0, -1, ec) < 0)
+      return invalid_socket;
+  }
+}
+
+#if defined(ASIO_HAS_IOCP)
+
+void complete_iocp_accept(socket_type s,
+    void* output_buffer, DWORD address_length,
+    socket_addr_type* addr, std::size_t* addrlen,
+    socket_type new_socket, asio::error_code& ec)
+{
+  // Map non-portable errors to their portable counterparts.
+  if (ec.value() == ERROR_NETNAME_DELETED)
+    ec = asio::error::connection_aborted;
+
+  if (!ec)
+  {
+    // Get the address of the peer.
+    if (addr && addrlen)
+    {
+      LPSOCKADDR local_addr = 0;
+      int local_addr_length = 0;
+      LPSOCKADDR remote_addr = 0;
+      int remote_addr_length = 0;
+      GetAcceptExSockaddrs(output_buffer, 0, address_length,
+          address_length, &local_addr, &local_addr_length,
+          &remote_addr, &remote_addr_length);
+      if (static_cast<std::size_t>(remote_addr_length) > *addrlen)
+      {
+        ec = asio::error::invalid_argument;
+      }
+      else
+      {
+        using namespace std; // For memcpy.
+        memcpy(addr, remote_addr, remote_addr_length);
+        *addrlen = static_cast<std::size_t>(remote_addr_length);
+      }
+    }
+
+    // Need to set the SO_UPDATE_ACCEPT_CONTEXT option so that getsockname
+    // and getpeername will work on the accepted socket.
+    SOCKET update_ctx_param = s;
+    socket_ops::state_type state = 0;
+    socket_ops::setsockopt(new_socket, state,
+          SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
+          &update_ctx_param, sizeof(SOCKET), ec);
+  }
+}
+
+#else // defined(ASIO_HAS_IOCP)
+
+bool non_blocking_accept(socket_type s,
+    state_type state, socket_addr_type* addr, std::size_t* addrlen,
+    asio::error_code& ec, socket_type& new_socket)
+{
+  for (;;)
+  {
+    // Accept the waiting connection.
+    new_socket = socket_ops::accept(s, addr, addrlen, ec);
+
+    // Check if operation succeeded.
+    if (new_socket != invalid_socket)
+      return true;
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Operation failed.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+    {
+      // Fall through to retry operation.
+    }
+    else if (ec == asio::error::connection_aborted)
+    {
+      if (state & enable_connection_aborted)
+        return true;
+      // Fall through to retry operation.
+    }
+#if defined(EPROTO)
+    else if (ec.value() == EPROTO)
+    {
+      if (state & enable_connection_aborted)
+        return true;
+      // Fall through to retry operation.
+    }
+#endif // defined(EPROTO)
+    else
+      return true;
+
+    return false;
+  }
+}
+
+#endif // defined(ASIO_HAS_IOCP)
+
+template <typename SockLenType>
+inline int call_bind(SockLenType msghdr::*,
+    socket_type s, const socket_addr_type* addr, std::size_t addrlen)
+{
+  return ::bind(s, addr, (SockLenType)addrlen);
+}
+
+int bind(socket_type s, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  clear_last_error();
+  int result = error_wrapper(call_bind(
+        &msghdr::msg_namelen, s, addr, addrlen), ec);
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int close(socket_type s, state_type& state,
+    bool destruction, asio::error_code& ec)
+{
+  int result = 0;
+  if (s != invalid_socket)
+  {
+    // We don't want the destructor to block, so set the socket to linger in
+    // the background. If the user doesn't like this behaviour then they need
+    // to explicitly close the socket.
+    if (destruction && (state & user_set_linger))
+    {
+      ::linger opt;
+      opt.l_onoff = 0;
+      opt.l_linger = 0;
+      asio::error_code ignored_ec;
+      socket_ops::setsockopt(s, state, SOL_SOCKET,
+          SO_LINGER, &opt, sizeof(opt), ignored_ec);
+    }
+
+    clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    result = error_wrapper(::closesocket(s), ec);
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    result = error_wrapper(::close(s), ec);
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+    if (result != 0
+        && (ec == asio::error::would_block
+          || ec == asio::error::try_again))
+    {
+      // According to UNIX Network Programming Vol. 1, it is possible for
+      // close() to fail with EWOULDBLOCK under certain circumstances. What
+      // isn't clear is the state of the descriptor after this error. The one
+      // current OS where this behaviour is seen, Windows, says that the socket
+      // remains open. Therefore we'll put the descriptor back into blocking
+      // mode and have another attempt at closing it.
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+      ioctl_arg_type arg = 0;
+      ::ioctlsocket(s, FIONBIO, &arg);
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if defined(__SYMBIAN32__)
+      int flags = ::fcntl(s, F_GETFL, 0);
+      if (flags >= 0)
+        ::fcntl(s, F_SETFL, flags & ~O_NONBLOCK);
+# else // defined(__SYMBIAN32__)
+      ioctl_arg_type arg = 0;
+      ::ioctl(s, FIONBIO, &arg);
+# endif // defined(__SYMBIAN32__)
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+      state &= ~non_blocking;
+
+      clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+      result = error_wrapper(::closesocket(s), ec);
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+      result = error_wrapper(::close(s), ec);
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    }
+  }
+
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+}
+
+bool set_user_non_blocking(socket_type s,
+    state_type& state, bool value, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return false;
+  }
+
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  ioctl_arg_type arg = (value ? 1 : 0);
+  int result = error_wrapper(::ioctlsocket(s, FIONBIO, &arg), ec);
+#elif defined(__SYMBIAN32__)
+  int result = error_wrapper(::fcntl(s, F_GETFL, 0), ec);
+  if (result >= 0)
+  {
+    clear_last_error();
+    int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
+    result = error_wrapper(::fcntl(s, F_SETFL, flag), ec);
+  }
+#else
+  ioctl_arg_type arg = (value ? 1 : 0);
+  int result = error_wrapper(::ioctl(s, FIONBIO, &arg), ec);
+#endif
+
+  if (result >= 0)
+  {
+    ec = asio::error_code();
+    if (value)
+      state |= user_set_non_blocking;
+    else
+    {
+      // Clearing the user-set non-blocking mode always overrides any
+      // internally-set non-blocking flag. Any subsequent asynchronous
+      // operations will need to re-enable non-blocking I/O.
+      state &= ~(user_set_non_blocking | internal_non_blocking);
+    }
+    return true;
+  }
+
+  return false;
+}
+
+bool set_internal_non_blocking(socket_type s,
+    state_type& state, bool value, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return false;
+  }
+
+  if (!value && (state & user_set_non_blocking))
+  {
+    // It does not make sense to clear the internal non-blocking flag if the
+    // user still wants non-blocking behaviour. Return an error and let the
+    // caller figure out whether to update the user-set non-blocking flag.
+    ec = asio::error::invalid_argument;
+    return false;
+  }
+
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  ioctl_arg_type arg = (value ? 1 : 0);
+  int result = error_wrapper(::ioctlsocket(s, FIONBIO, &arg), ec);
+#elif defined(__SYMBIAN32__)
+  int result = error_wrapper(::fcntl(s, F_GETFL, 0), ec);
+  if (result >= 0)
+  {
+    clear_last_error();
+    int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
+    result = error_wrapper(::fcntl(s, F_SETFL, flag), ec);
+  }
+#else
+  ioctl_arg_type arg = (value ? 1 : 0);
+  int result = error_wrapper(::ioctl(s, FIONBIO, &arg), ec);
+#endif
+
+  if (result >= 0)
+  {
+    ec = asio::error_code();
+    if (value)
+      state |= internal_non_blocking;
+    else
+      state &= ~internal_non_blocking;
+    return true;
+  }
+
+  return false;
+}
+
+int shutdown(socket_type s, int what, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  clear_last_error();
+  int result = error_wrapper(::shutdown(s, what), ec);
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+}
+
+template <typename SockLenType>
+inline int call_connect(SockLenType msghdr::*,
+    socket_type s, const socket_addr_type* addr, std::size_t addrlen)
+{
+  return ::connect(s, addr, (SockLenType)addrlen);
+}
+
+int connect(socket_type s, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  clear_last_error();
+  int result = error_wrapper(call_connect(
+        &msghdr::msg_namelen, s, addr, addrlen), ec);
+  if (result == 0)
+    ec = asio::error_code();
+#if defined(__linux__)
+  else if (ec == asio::error::try_again)
+    ec = asio::error::no_buffer_space;
+#endif // defined(__linux__)
+  return result;
+}
+
+void sync_connect(socket_type s, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec)
+{
+  // Perform the connect operation.
+  socket_ops::connect(s, addr, addrlen, ec);
+  if (ec != asio::error::in_progress
+      && ec != asio::error::would_block)
+  {
+    // The connect operation finished immediately.
+    return;
+  }
+
+  // Wait for socket to become ready.
+  if (socket_ops::poll_connect(s, -1, ec) < 0)
+    return;
+
+  // Get the error code from the connect operation.
+  int connect_error = 0;
+  size_t connect_error_len = sizeof(connect_error);
+  if (socket_ops::getsockopt(s, 0, SOL_SOCKET, SO_ERROR,
+        &connect_error, &connect_error_len, ec) == socket_error_retval)
+    return;
+
+  // Return the result of the connect operation.
+  ec = asio::error_code(connect_error,
+      asio::error::get_system_category());
+}
+
+#if defined(ASIO_HAS_IOCP)
+
+void complete_iocp_connect(socket_type s, asio::error_code& ec)
+{
+  // Map non-portable errors to their portable counterparts.
+  switch (ec.value())
+  {
+  case ERROR_CONNECTION_REFUSED:
+    ec = asio::error::connection_refused;
+    break;
+  case ERROR_NETWORK_UNREACHABLE:
+    ec = asio::error::network_unreachable;
+    break;
+  case ERROR_HOST_UNREACHABLE:
+    ec = asio::error::host_unreachable;
+    break;
+  case ERROR_SEM_TIMEOUT:
+    ec = asio::error::timed_out;
+    break;
+  default:
+    break;
+  }
+
+  if (!ec)
+  {
+    // Need to set the SO_UPDATE_CONNECT_CONTEXT option so that getsockname
+    // and getpeername will work on the connected socket.
+    socket_ops::state_type state = 0;
+    const int so_update_connect_context = 0x7010;
+    socket_ops::setsockopt(s, state, SOL_SOCKET,
+        so_update_connect_context, 0, 0, ec);
+  }
+}
+
+#endif // defined(ASIO_HAS_IOCP)
+
+bool non_blocking_connect(socket_type s, asio::error_code& ec)
+{
+  // Check if the connect operation has finished. This is required since we may
+  // get spurious readiness notifications from the reactor.
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+  fd_set write_fds;
+  FD_ZERO(&write_fds);
+  FD_SET(s, &write_fds);
+  fd_set except_fds;
+  FD_ZERO(&except_fds);
+  FD_SET(s, &except_fds);
+  timeval zero_timeout;
+  zero_timeout.tv_sec = 0;
+  zero_timeout.tv_usec = 0;
+  int ready = ::select(s + 1, 0, &write_fds, &except_fds, &zero_timeout);
+#else // defined(ASIO_WINDOWS)
+      // || defined(__CYGWIN__)
+      // || defined(__SYMBIAN32__)
+  pollfd fds;
+  fds.fd = s;
+  fds.events = POLLOUT;
+  fds.revents = 0;
+  int ready = ::poll(&fds, 1, 0);
+#endif // defined(ASIO_WINDOWS)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+  if (ready == 0)
+  {
+    // The asynchronous connect operation is still in progress.
+    return false;
+  }
+
+  // Get the error code from the connect operation.
+  int connect_error = 0;
+  size_t connect_error_len = sizeof(connect_error);
+  if (socket_ops::getsockopt(s, 0, SOL_SOCKET, SO_ERROR,
+        &connect_error, &connect_error_len, ec) == 0)
+  {
+    if (connect_error)
+    {
+      ec = asio::error_code(connect_error,
+          asio::error::get_system_category());
+    }
+    else
+      ec = asio::error_code();
+  }
+
+  return true;
+}
+
+int socketpair(int af, int type, int protocol,
+    socket_type sv[2], asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  (void)(af);
+  (void)(type);
+  (void)(protocol);
+  (void)(sv);
+  ec = asio::error::operation_not_supported;
+  return socket_error_retval;
+#else
+  clear_last_error();
+  int result = error_wrapper(::socketpair(af, type, protocol, sv), ec);
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+#endif
+}
+
+bool sockatmark(socket_type s, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return false;
+  }
+
+#if defined(SIOCATMARK)
+  ioctl_arg_type value = 0;
+# if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  int result = error_wrapper(::ioctlsocket(s, SIOCATMARK, &value), ec);
+# else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  int result = error_wrapper(::ioctl(s, SIOCATMARK, &value), ec);
+# endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  if (result == 0)
+    ec = asio::error_code();
+# if defined(ENOTTY)
+  if (ec.value() == ENOTTY)
+    ec = asio::error::not_socket;
+# endif // defined(ENOTTY)
+#else // defined(SIOCATMARK)
+  int value = error_wrapper(::sockatmark(s), ec);
+  if (value != -1)
+    ec = asio::error_code();
+#endif // defined(SIOCATMARK)
+
+  return ec ? false : value != 0;
+}
+
+size_t available(socket_type s, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  ioctl_arg_type value = 0;
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  int result = error_wrapper(::ioctlsocket(s, FIONREAD, &value), ec);
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  int result = error_wrapper(::ioctl(s, FIONREAD, &value), ec);
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  if (result == 0)
+    ec = asio::error_code();
+#if defined(ENOTTY)
+  if (ec.value() == ENOTTY)
+    ec = asio::error::not_socket;
+#endif // defined(ENOTTY)
+
+  return ec ? static_cast<size_t>(0) : static_cast<size_t>(value);
+}
+
+int listen(socket_type s, int backlog, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  clear_last_error();
+  int result = error_wrapper(::listen(s, backlog), ec);
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+}
+
+inline void init_buf_iov_base(void*& base, void* addr)
+{
+  base = addr;
+}
+
+template <typename T>
+inline void init_buf_iov_base(T& base, void* addr)
+{
+  base = static_cast<T>(addr);
+}
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+typedef WSABUF buf;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+typedef iovec buf;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+void init_buf(buf& b, void* data, size_t size)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  b.buf = static_cast<char*>(data);
+  b.len = static_cast<u_long>(size);
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  init_buf_iov_base(b.iov_base, data);
+  b.iov_len = size;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+void init_buf(buf& b, const void* data, size_t size)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  b.buf = static_cast<char*>(const_cast<void*>(data));
+  b.len = static_cast<u_long>(size);
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  init_buf_iov_base(b.iov_base, const_cast<void*>(data));
+  b.iov_len = size;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+inline void init_msghdr_msg_name(void*& name, socket_addr_type* addr)
+{
+  name = addr;
+}
+
+inline void init_msghdr_msg_name(void*& name, const socket_addr_type* addr)
+{
+  name = const_cast<socket_addr_type*>(addr);
+}
+
+template <typename T>
+inline void init_msghdr_msg_name(T& name, socket_addr_type* addr)
+{
+  name = reinterpret_cast<T>(addr);
+}
+
+template <typename T>
+inline void init_msghdr_msg_name(T& name, const socket_addr_type* addr)
+{
+  name = reinterpret_cast<T>(const_cast<socket_addr_type*>(addr));
+}
+
+signed_size_type recv(socket_type s, buf* bufs, size_t count,
+    int flags, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  // Receive some data.
+  DWORD recv_buf_count = static_cast<DWORD>(count);
+  DWORD bytes_transferred = 0;
+  DWORD recv_flags = flags;
+  int result = error_wrapper(::WSARecv(s, bufs,
+        recv_buf_count, &bytes_transferred, &recv_flags, 0, 0), ec);
+  if (ec.value() == ERROR_NETNAME_DELETED)
+    ec = asio::error::connection_reset;
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+    ec = asio::error::connection_refused;
+  else if (ec.value() == WSAEMSGSIZE || ec.value() == ERROR_MORE_DATA)
+    ec.assign(0, ec.category());
+  if (result != 0)
+    return socket_error_retval;
+  ec = asio::error_code();
+  return bytes_transferred;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  msghdr msg = msghdr();
+  msg.msg_iov = bufs;
+  msg.msg_iovlen = static_cast<int>(count);
+  signed_size_type result = error_wrapper(::recvmsg(s, &msg, flags), ec);
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+size_t sync_recv(socket_type s, state_type state, buf* bufs,
+    size_t count, int flags, bool all_empty, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // A request to read 0 bytes on a stream is a no-op.
+  if (all_empty && (state & stream_oriented))
+  {
+    ec = asio::error_code();
+    return 0;
+  }
+
+  // Read some data.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    signed_size_type bytes = socket_ops::recv(s, bufs, count, flags, ec);
+
+    // Check if operation succeeded.
+    if (bytes > 0)
+      return bytes;
+
+    // Check for EOF.
+    if ((state & stream_oriented) && bytes == 0)
+    {
+      ec = asio::error::eof;
+      return 0;
+    }
+
+    // Operation failed.
+    if ((state & user_set_non_blocking)
+        || (ec != asio::error::would_block
+          && ec != asio::error::try_again))
+      return 0;
+
+    // Wait for socket to become ready.
+    if (socket_ops::poll_read(s, 0, -1, ec) < 0)
+      return 0;
+  }
+}
+
+#if defined(ASIO_HAS_IOCP)
+
+void complete_iocp_recv(state_type state,
+    const weak_cancel_token_type& cancel_token, bool all_empty,
+    asio::error_code& ec, size_t bytes_transferred)
+{
+  // Map non-portable errors to their portable counterparts.
+  if (ec.value() == ERROR_NETNAME_DELETED)
+  {
+    if (cancel_token.expired())
+      ec = asio::error::operation_aborted;
+    else
+      ec = asio::error::connection_reset;
+  }
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+  {
+    ec = asio::error::connection_refused;
+  }
+  else if (ec.value() == WSAEMSGSIZE || ec.value() == ERROR_MORE_DATA)
+  {
+    ec.assign(0, ec.category());
+  }
+
+  // Check for connection closed.
+  else if (!ec && bytes_transferred == 0
+      && (state & stream_oriented) != 0
+      && !all_empty)
+  {
+    ec = asio::error::eof;
+  }
+}
+
+#else // defined(ASIO_HAS_IOCP)
+
+bool non_blocking_recv(socket_type s,
+    buf* bufs, size_t count, int flags, bool is_stream,
+    asio::error_code& ec, size_t& bytes_transferred)
+{
+  for (;;)
+  {
+    // Read some data.
+    signed_size_type bytes = socket_ops::recv(s, bufs, count, flags, ec);
+
+    // Check for end of stream.
+    if (is_stream && bytes == 0)
+    {
+      ec = asio::error::eof;
+      return true;
+    }
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Check if we need to run the operation again.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+      return false;
+
+    // Operation is complete.
+    if (bytes >= 0)
+    {
+      ec = asio::error_code();
+      bytes_transferred = bytes;
+    }
+    else
+      bytes_transferred = 0;
+
+    return true;
+  }
+}
+
+#endif // defined(ASIO_HAS_IOCP)
+
+signed_size_type recvfrom(socket_type s, buf* bufs, size_t count,
+    int flags, socket_addr_type* addr, std::size_t* addrlen,
+    asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  // Receive some data.
+  DWORD recv_buf_count = static_cast<DWORD>(count);
+  DWORD bytes_transferred = 0;
+  DWORD recv_flags = flags;
+  int tmp_addrlen = (int)*addrlen;
+  int result = error_wrapper(::WSARecvFrom(s, bufs, recv_buf_count,
+        &bytes_transferred, &recv_flags, addr, &tmp_addrlen, 0, 0), ec);
+  *addrlen = (std::size_t)tmp_addrlen;
+  if (ec.value() == ERROR_NETNAME_DELETED)
+    ec = asio::error::connection_reset;
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+    ec = asio::error::connection_refused;
+  else if (ec.value() == WSAEMSGSIZE || ec.value() == ERROR_MORE_DATA)
+    ec.assign(0, ec.category());
+  if (result != 0)
+    return socket_error_retval;
+  ec = asio::error_code();
+  return bytes_transferred;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  msghdr msg = msghdr();
+  init_msghdr_msg_name(msg.msg_name, addr);
+  msg.msg_namelen = static_cast<int>(*addrlen);
+  msg.msg_iov = bufs;
+  msg.msg_iovlen = static_cast<int>(count);
+  signed_size_type result = error_wrapper(::recvmsg(s, &msg, flags), ec);
+  *addrlen = msg.msg_namelen;
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+size_t sync_recvfrom(socket_type s, state_type state, buf* bufs,
+    size_t count, int flags, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // Read some data.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    signed_size_type bytes = socket_ops::recvfrom(
+        s, bufs, count, flags, addr, addrlen, ec);
+
+    // Check if operation succeeded.
+    if (bytes >= 0)
+      return bytes;
+
+    // Operation failed.
+    if ((state & user_set_non_blocking)
+        || (ec != asio::error::would_block
+          && ec != asio::error::try_again))
+      return 0;
+
+    // Wait for socket to become ready.
+    if (socket_ops::poll_read(s, 0, -1, ec) < 0)
+      return 0;
+  }
+}
+
+#if defined(ASIO_HAS_IOCP)
+
+void complete_iocp_recvfrom(
+    const weak_cancel_token_type& cancel_token,
+    asio::error_code& ec)
+{
+  // Map non-portable errors to their portable counterparts.
+  if (ec.value() == ERROR_NETNAME_DELETED)
+  {
+    if (cancel_token.expired())
+      ec = asio::error::operation_aborted;
+    else
+      ec = asio::error::connection_reset;
+  }
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+  {
+    ec = asio::error::connection_refused;
+  }
+  else if (ec.value() == WSAEMSGSIZE || ec.value() == ERROR_MORE_DATA)
+  {
+    ec.assign(0, ec.category());
+  }
+}
+
+#else // defined(ASIO_HAS_IOCP)
+
+bool non_blocking_recvfrom(socket_type s,
+    buf* bufs, size_t count, int flags,
+    socket_addr_type* addr, std::size_t* addrlen,
+    asio::error_code& ec, size_t& bytes_transferred)
+{
+  for (;;)
+  {
+    // Read some data.
+    signed_size_type bytes = socket_ops::recvfrom(
+        s, bufs, count, flags, addr, addrlen, ec);
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Check if we need to run the operation again.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+      return false;
+
+    // Operation is complete.
+    if (bytes >= 0)
+    {
+      ec = asio::error_code();
+      bytes_transferred = bytes;
+    }
+    else
+      bytes_transferred = 0;
+
+    return true;
+  }
+}
+
+#endif // defined(ASIO_HAS_IOCP)
+
+signed_size_type recvmsg(socket_type s, buf* bufs, size_t count,
+    int in_flags, int& out_flags, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  out_flags = 0;
+  return socket_ops::recv(s, bufs, count, in_flags, ec);
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  msghdr msg = msghdr();
+  msg.msg_iov = bufs;
+  msg.msg_iovlen = static_cast<int>(count);
+  signed_size_type result = error_wrapper(::recvmsg(s, &msg, in_flags), ec);
+  if (result >= 0)
+  {
+    ec = asio::error_code();
+    out_flags = msg.msg_flags;
+  }
+  else
+    out_flags = 0;
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+size_t sync_recvmsg(socket_type s, state_type state,
+    buf* bufs, size_t count, int in_flags, int& out_flags,
+    asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // Read some data.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    signed_size_type bytes = socket_ops::recvmsg(
+        s, bufs, count, in_flags, out_flags, ec);
+
+    // Check if operation succeeded.
+    if (bytes >= 0)
+      return bytes;
+
+    // Operation failed.
+    if ((state & user_set_non_blocking)
+        || (ec != asio::error::would_block
+          && ec != asio::error::try_again))
+      return 0;
+
+    // Wait for socket to become ready.
+    if (socket_ops::poll_read(s, 0, -1, ec) < 0)
+      return 0;
+  }
+}
+
+#if defined(ASIO_HAS_IOCP)
+
+void complete_iocp_recvmsg(
+    const weak_cancel_token_type& cancel_token,
+    asio::error_code& ec)
+{
+  // Map non-portable errors to their portable counterparts.
+  if (ec.value() == ERROR_NETNAME_DELETED)
+  {
+    if (cancel_token.expired())
+      ec = asio::error::operation_aborted;
+    else
+      ec = asio::error::connection_reset;
+  }
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+  {
+    ec = asio::error::connection_refused;
+  }
+  else if (ec.value() == WSAEMSGSIZE || ec.value() == ERROR_MORE_DATA)
+  {
+    ec.assign(0, ec.category());
+  }
+}
+
+#else // defined(ASIO_HAS_IOCP)
+
+bool non_blocking_recvmsg(socket_type s,
+    buf* bufs, size_t count, int in_flags, int& out_flags,
+    asio::error_code& ec, size_t& bytes_transferred)
+{
+  for (;;)
+  {
+    // Read some data.
+    signed_size_type bytes = socket_ops::recvmsg(
+        s, bufs, count, in_flags, out_flags, ec);
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Check if we need to run the operation again.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+      return false;
+
+    // Operation is complete.
+    if (bytes >= 0)
+    {
+      ec = asio::error_code();
+      bytes_transferred = bytes;
+    }
+    else
+      bytes_transferred = 0;
+
+    return true;
+  }
+}
+
+#endif // defined(ASIO_HAS_IOCP)
+
+signed_size_type send(socket_type s, const buf* bufs, size_t count,
+    int flags, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  // Send the data.
+  DWORD send_buf_count = static_cast<DWORD>(count);
+  DWORD bytes_transferred = 0;
+  DWORD send_flags = flags;
+  int result = error_wrapper(::WSASend(s, const_cast<buf*>(bufs),
+        send_buf_count, &bytes_transferred, send_flags, 0, 0), ec);
+  if (ec.value() == ERROR_NETNAME_DELETED)
+    ec = asio::error::connection_reset;
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+    ec = asio::error::connection_refused;
+  if (result != 0)
+    return socket_error_retval;
+  ec = asio::error_code();
+  return bytes_transferred;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  msghdr msg = msghdr();
+  msg.msg_iov = const_cast<buf*>(bufs);
+  msg.msg_iovlen = static_cast<int>(count);
+#if defined(__linux__)
+  flags |= MSG_NOSIGNAL;
+#endif // defined(__linux__)
+  signed_size_type result = error_wrapper(::sendmsg(s, &msg, flags), ec);
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+size_t sync_send(socket_type s, state_type state, const buf* bufs,
+    size_t count, int flags, bool all_empty, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // A request to write 0 bytes to a stream is a no-op.
+  if (all_empty && (state & stream_oriented))
+  {
+    ec = asio::error_code();
+    return 0;
+  }
+
+  // Read some data.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    signed_size_type bytes = socket_ops::send(s, bufs, count, flags, ec);
+
+    // Check if operation succeeded.
+    if (bytes >= 0)
+      return bytes;
+
+    // Operation failed.
+    if ((state & user_set_non_blocking)
+        || (ec != asio::error::would_block
+          && ec != asio::error::try_again))
+      return 0;
+
+    // Wait for socket to become ready.
+    if (socket_ops::poll_write(s, 0, -1, ec) < 0)
+      return 0;
+  }
+}
+
+#if defined(ASIO_HAS_IOCP)
+
+void complete_iocp_send(
+    const weak_cancel_token_type& cancel_token,
+    asio::error_code& ec)
+{
+  // Map non-portable errors to their portable counterparts.
+  if (ec.value() == ERROR_NETNAME_DELETED)
+  {
+    if (cancel_token.expired())
+      ec = asio::error::operation_aborted;
+    else
+      ec = asio::error::connection_reset;
+  }
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+  {
+    ec = asio::error::connection_refused;
+  }
+}
+
+#else // defined(ASIO_HAS_IOCP)
+
+bool non_blocking_send(socket_type s,
+    const buf* bufs, size_t count, int flags,
+    asio::error_code& ec, size_t& bytes_transferred)
+{
+  for (;;)
+  {
+    // Write some data.
+    signed_size_type bytes = socket_ops::send(s, bufs, count, flags, ec);
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Check if we need to run the operation again.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+      return false;
+
+    // Operation is complete.
+    if (bytes >= 0)
+    {
+      ec = asio::error_code();
+      bytes_transferred = bytes;
+    }
+    else
+      bytes_transferred = 0;
+
+    return true;
+  }
+}
+
+#endif // defined(ASIO_HAS_IOCP)
+
+signed_size_type sendto(socket_type s, const buf* bufs, size_t count,
+    int flags, const socket_addr_type* addr, std::size_t addrlen,
+    asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  // Send the data.
+  DWORD send_buf_count = static_cast<DWORD>(count);
+  DWORD bytes_transferred = 0;
+  int result = error_wrapper(::WSASendTo(s, const_cast<buf*>(bufs),
+        send_buf_count, &bytes_transferred, flags, addr,
+        static_cast<int>(addrlen), 0, 0), ec);
+  if (ec.value() == ERROR_NETNAME_DELETED)
+    ec = asio::error::connection_reset;
+  else if (ec.value() == ERROR_PORT_UNREACHABLE)
+    ec = asio::error::connection_refused;
+  if (result != 0)
+    return socket_error_retval;
+  ec = asio::error_code();
+  return bytes_transferred;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  msghdr msg = msghdr();
+  init_msghdr_msg_name(msg.msg_name, addr);
+  msg.msg_namelen = static_cast<int>(addrlen);
+  msg.msg_iov = const_cast<buf*>(bufs);
+  msg.msg_iovlen = static_cast<int>(count);
+#if defined(__linux__)
+  flags |= MSG_NOSIGNAL;
+#endif // defined(__linux__)
+  signed_size_type result = error_wrapper(::sendmsg(s, &msg, flags), ec);
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+size_t sync_sendto(socket_type s, state_type state, const buf* bufs,
+    size_t count, int flags, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // Write some data.
+  for (;;)
+  {
+    // Try to complete the operation without blocking.
+    signed_size_type bytes = socket_ops::sendto(
+        s, bufs, count, flags, addr, addrlen, ec);
+
+    // Check if operation succeeded.
+    if (bytes >= 0)
+      return bytes;
+
+    // Operation failed.
+    if ((state & user_set_non_blocking)
+        || (ec != asio::error::would_block
+          && ec != asio::error::try_again))
+      return 0;
+
+    // Wait for socket to become ready.
+    if (socket_ops::poll_write(s, 0, -1, ec) < 0)
+      return 0;
+  }
+}
+
+#if !defined(ASIO_HAS_IOCP)
+
+bool non_blocking_sendto(socket_type s,
+    const buf* bufs, size_t count, int flags,
+    const socket_addr_type* addr, std::size_t addrlen,
+    asio::error_code& ec, size_t& bytes_transferred)
+{
+  for (;;)
+  {
+    // Write some data.
+    signed_size_type bytes = socket_ops::sendto(
+        s, bufs, count, flags, addr, addrlen, ec);
+
+    // Retry operation if interrupted by signal.
+    if (ec == asio::error::interrupted)
+      continue;
+
+    // Check if we need to run the operation again.
+    if (ec == asio::error::would_block
+        || ec == asio::error::try_again)
+      return false;
+
+    // Operation is complete.
+    if (bytes >= 0)
+    {
+      ec = asio::error_code();
+      bytes_transferred = bytes;
+    }
+    else
+      bytes_transferred = 0;
+
+    return true;
+  }
+}
+
+#endif // !defined(ASIO_HAS_IOCP)
+
+socket_type socket(int af, int type, int protocol,
+    asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  socket_type s = error_wrapper(::WSASocketW(af, type, protocol, 0, 0,
+        WSA_FLAG_OVERLAPPED), ec);
+  if (s == invalid_socket)
+    return s;
+
+  if (af == ASIO_OS_DEF(AF_INET6))
+  {
+    // Try to enable the POSIX default behaviour of having IPV6_V6ONLY set to
+    // false. This will only succeed on Windows Vista and later versions of
+    // Windows, where a dual-stack IPv4/v6 implementation is available.
+    DWORD optval = 0;
+    ::setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
+        reinterpret_cast<const char*>(&optval), sizeof(optval));
+  }
+
+  ec = asio::error_code();
+
+  return s;
+#elif defined(__MACH__) && defined(__APPLE__) || defined(__FreeBSD__)
+  socket_type s = error_wrapper(::socket(af, type, protocol), ec);
+  if (s == invalid_socket)
+    return s;
+
+  int optval = 1;
+  int result = error_wrapper(::setsockopt(s,
+        SOL_SOCKET, SO_NOSIGPIPE, &optval, sizeof(optval)), ec);
+  if (result != 0)
+  {
+    ::close(s);
+    return invalid_socket;
+  }
+
+  return s;
+#else
+  int s = error_wrapper(::socket(af, type, protocol), ec);
+  if (s >= 0)
+    ec = asio::error_code();
+  return s;
+#endif
+}
+
+template <typename SockLenType>
+inline int call_setsockopt(SockLenType msghdr::*,
+    socket_type s, int level, int optname,
+    const void* optval, std::size_t optlen)
+{
+  return ::setsockopt(s, level, optname,
+      (const char*)optval, (SockLenType)optlen);
+}
+
+int setsockopt(socket_type s, state_type& state, int level, int optname,
+    const void* optval, std::size_t optlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  if (level == custom_socket_option_level && optname == always_fail_option)
+  {
+    ec = asio::error::invalid_argument;
+    return socket_error_retval;
+  }
+
+  if (level == custom_socket_option_level
+      && optname == enable_connection_aborted_option)
+  {
+    if (optlen != sizeof(int))
+    {
+      ec = asio::error::invalid_argument;
+      return socket_error_retval;
+    }
+
+    if (*static_cast<const int*>(optval))
+      state |= enable_connection_aborted;
+    else
+      state &= ~enable_connection_aborted;
+    ec = asio::error_code();
+    return 0;
+  }
+
+  if (level == SOL_SOCKET && optname == SO_LINGER)
+    state |= user_set_linger;
+
+#if defined(__BORLANDC__)
+  // Mysteriously, using the getsockopt and setsockopt functions directly with
+  // Borland C++ results in incorrect values being set and read. The bug can be
+  // worked around by using function addresses resolved with GetProcAddress.
+  if (HMODULE winsock_module = ::GetModuleHandleA("ws2_32"))
+  {
+    typedef int (WSAAPI *sso_t)(SOCKET, int, int, const char*, int);
+    if (sso_t sso = (sso_t)::GetProcAddress(winsock_module, "setsockopt"))
+    {
+      clear_last_error();
+      return error_wrapper(sso(s, level, optname,
+            reinterpret_cast<const char*>(optval),
+            static_cast<int>(optlen)), ec);
+    }
+  }
+  ec = asio::error::fault;
+  return socket_error_retval;
+#else // defined(__BORLANDC__)
+  clear_last_error();
+  int result = error_wrapper(call_setsockopt(&msghdr::msg_namelen,
+        s, level, optname, optval, optlen), ec);
+  if (result == 0)
+  {
+    ec = asio::error_code();
+
+#if defined(__MACH__) && defined(__APPLE__) \
+  || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
+    // To implement portable behaviour for SO_REUSEADDR with UDP sockets we
+    // need to also set SO_REUSEPORT on BSD-based platforms.
+    if ((state & datagram_oriented)
+        && level == SOL_SOCKET && optname == SO_REUSEADDR)
+    {
+      call_setsockopt(&msghdr::msg_namelen, s,
+          SOL_SOCKET, SO_REUSEPORT, optval, optlen);
+    }
+#endif
+  }
+
+  return result;
+#endif // defined(__BORLANDC__)
+}
+
+template <typename SockLenType>
+inline int call_getsockopt(SockLenType msghdr::*,
+    socket_type s, int level, int optname,
+    void* optval, std::size_t* optlen)
+{
+  SockLenType tmp_optlen = (SockLenType)*optlen;
+  int result = ::getsockopt(s, level, optname, (char*)optval, &tmp_optlen);
+  *optlen = (std::size_t)tmp_optlen;
+  return result;
+}
+
+int getsockopt(socket_type s, state_type state, int level, int optname,
+    void* optval, size_t* optlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  if (level == custom_socket_option_level && optname == always_fail_option)
+  {
+    ec = asio::error::invalid_argument;
+    return socket_error_retval;
+  }
+
+  if (level == custom_socket_option_level
+      && optname == enable_connection_aborted_option)
+  {
+    if (*optlen != sizeof(int))
+    {
+      ec = asio::error::invalid_argument;
+      return socket_error_retval;
+    }
+
+    *static_cast<int*>(optval) = (state & enable_connection_aborted) ? 1 : 0;
+    ec = asio::error_code();
+    return 0;
+  }
+
+#if defined(__BORLANDC__)
+  // Mysteriously, using the getsockopt and setsockopt functions directly with
+  // Borland C++ results in incorrect values being set and read. The bug can be
+  // worked around by using function addresses resolved with GetProcAddress.
+  if (HMODULE winsock_module = ::GetModuleHandleA("ws2_32"))
+  {
+    typedef int (WSAAPI *gso_t)(SOCKET, int, int, char*, int*);
+    if (gso_t gso = (gso_t)::GetProcAddress(winsock_module, "getsockopt"))
+    {
+      clear_last_error();
+      int tmp_optlen = static_cast<int>(*optlen);
+      int result = error_wrapper(gso(s, level, optname,
+            reinterpret_cast<char*>(optval), &tmp_optlen), ec);
+      *optlen = static_cast<size_t>(tmp_optlen);
+      if (result != 0 && level == IPPROTO_IPV6 && optname == IPV6_V6ONLY
+          && ec.value() == WSAENOPROTOOPT && *optlen == sizeof(DWORD))
+      {
+        // Dual-stack IPv4/v6 sockets, and the IPV6_V6ONLY socket option, are
+        // only supported on Windows Vista and later. To simplify program logic
+        // we will fake success of getting this option and specify that the
+        // value is non-zero (i.e. true). This corresponds to the behavior of
+        // IPv6 sockets on Windows platforms pre-Vista.
+        *static_cast<DWORD*>(optval) = 1;
+        ec = asio::error_code();
+      }
+      return result;
+    }
+  }
+  ec = asio::error::fault;
+  return socket_error_retval;
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  clear_last_error();
+  int result = error_wrapper(call_getsockopt(&msghdr::msg_namelen,
+        s, level, optname, optval, optlen), ec);
+  if (result != 0 && level == IPPROTO_IPV6 && optname == IPV6_V6ONLY
+      && ec.value() == WSAENOPROTOOPT && *optlen == sizeof(DWORD))
+  {
+    // Dual-stack IPv4/v6 sockets, and the IPV6_V6ONLY socket option, are only
+    // supported on Windows Vista and later. To simplify program logic we will
+    // fake success of getting this option and specify that the value is
+    // non-zero (i.e. true). This corresponds to the behavior of IPv6 sockets
+    // on Windows platforms pre-Vista.
+    *static_cast<DWORD*>(optval) = 1;
+    ec = asio::error_code();
+  }
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  clear_last_error();
+  int result = error_wrapper(call_getsockopt(&msghdr::msg_namelen,
+        s, level, optname, optval, optlen), ec);
+#if defined(__linux__)
+  if (result == 0 && level == SOL_SOCKET && *optlen == sizeof(int)
+      && (optname == SO_SNDBUF || optname == SO_RCVBUF))
+  {
+    // On Linux, setting SO_SNDBUF or SO_RCVBUF to N actually causes the kernel
+    // to set the buffer size to N*2. Linux puts additional stuff into the
+    // buffers so that only about half is actually available to the application.
+    // The retrieved value is divided by 2 here to make it appear as though the
+    // correct value has been set.
+    *static_cast<int*>(optval) /= 2;
+  }
+#endif // defined(__linux__)
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+template <typename SockLenType>
+inline int call_getpeername(SockLenType msghdr::*,
+    socket_type s, socket_addr_type* addr, std::size_t* addrlen)
+{
+  SockLenType tmp_addrlen = (SockLenType)*addrlen;
+  int result = ::getpeername(s, addr, &tmp_addrlen);
+  *addrlen = (std::size_t)tmp_addrlen;
+  return result;
+}
+
+int getpeername(socket_type s, socket_addr_type* addr,
+    std::size_t* addrlen, bool cached, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+#if defined(ASIO_WINDOWS) && !defined(ASIO_WINDOWS_APP) \
+  || defined(__CYGWIN__)
+  if (cached)
+  {
+    // Check if socket is still connected.
+    DWORD connect_time = 0;
+    size_t connect_time_len = sizeof(connect_time);
+    if (socket_ops::getsockopt(s, 0, SOL_SOCKET, SO_CONNECT_TIME,
+          &connect_time, &connect_time_len, ec) == socket_error_retval)
+    {
+      return socket_error_retval;
+    }
+    if (connect_time == 0xFFFFFFFF)
+    {
+      ec = asio::error::not_connected;
+      return socket_error_retval;
+    }
+
+    // The cached value is still valid.
+    ec = asio::error_code();
+    return 0;
+  }
+#else // defined(ASIO_WINDOWS) && !defined(ASIO_WINDOWS_APP)
+      // || defined(__CYGWIN__)
+  (void)cached;
+#endif // defined(ASIO_WINDOWS) && !defined(ASIO_WINDOWS_APP)
+       // || defined(__CYGWIN__)
+
+  clear_last_error();
+  int result = error_wrapper(call_getpeername(
+        &msghdr::msg_namelen, s, addr, addrlen), ec);
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+}
+
+template <typename SockLenType>
+inline int call_getsockname(SockLenType msghdr::*,
+    socket_type s, socket_addr_type* addr, std::size_t* addrlen)
+{
+  SockLenType tmp_addrlen = (SockLenType)*addrlen;
+  int result = ::getsockname(s, addr, &tmp_addrlen);
+  *addrlen = (std::size_t)tmp_addrlen;
+  return result;
+}
+
+int getsockname(socket_type s, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  clear_last_error();
+  int result = error_wrapper(call_getsockname(
+        &msghdr::msg_namelen, s, addr, addrlen), ec);
+  if (result == 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int ioctl(socket_type s, state_type& state, int cmd,
+    ioctl_arg_type* arg, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  int result = error_wrapper(::ioctlsocket(s, cmd, arg), ec);
+#elif defined(__MACH__) && defined(__APPLE__) \
+  || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
+  int result = error_wrapper(::ioctl(s,
+        static_cast<unsigned int>(cmd), arg), ec);
+#else
+  int result = error_wrapper(::ioctl(s, cmd, arg), ec);
+#endif
+  if (result >= 0)
+  {
+    ec = asio::error_code();
+
+    // When updating the non-blocking mode we always perform the ioctl syscall,
+    // even if the flags would otherwise indicate that the socket is already in
+    // the correct state. This ensures that the underlying socket is put into
+    // the state that has been requested by the user. If the ioctl syscall was
+    // successful then we need to update the flags to match.
+    if (cmd == static_cast<int>(FIONBIO))
+    {
+      if (*arg)
+      {
+        state |= user_set_non_blocking;
+      }
+      else
+      {
+        // Clearing the non-blocking mode always overrides any internally-set
+        // non-blocking flag. Any subsequent asynchronous operations will need
+        // to re-enable non-blocking I/O.
+        state &= ~(user_set_non_blocking | internal_non_blocking);
+      }
+    }
+  }
+
+  return result;
+}
+
+int select(int nfds, fd_set* readfds, fd_set* writefds,
+    fd_set* exceptfds, timeval* timeout, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  if (!readfds && !writefds && !exceptfds && timeout)
+  {
+    DWORD milliseconds = timeout->tv_sec * 1000 + timeout->tv_usec / 1000;
+    if (milliseconds == 0)
+      milliseconds = 1; // Force context switch.
+    ::Sleep(milliseconds);
+    ec = asio::error_code();
+    return 0;
+  }
+
+  // The select() call allows timeout values measured in microseconds, but the
+  // system clock (as wrapped by boost::posix_time::microsec_clock) typically
+  // has a resolution of 10 milliseconds. This can lead to a spinning select
+  // reactor, meaning increased CPU usage, when waiting for the earliest
+  // scheduled timeout if it's less than 10 milliseconds away. To avoid a tight
+  // spin we'll use a minimum timeout of 1 millisecond.
+  if (timeout && timeout->tv_sec == 0
+      && timeout->tv_usec > 0 && timeout->tv_usec < 1000)
+    timeout->tv_usec = 1000;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#if defined(__hpux) && defined(__SELECT)
+  timespec ts;
+  ts.tv_sec = timeout ? timeout->tv_sec : 0;
+  ts.tv_nsec = timeout ? timeout->tv_usec * 1000 : 0;
+  return error_wrapper(::pselect(nfds, readfds,
+        writefds, exceptfds, timeout ? &ts : 0, 0), ec);
+#else
+  int result = error_wrapper(::select(nfds, readfds,
+        writefds, exceptfds, timeout), ec);
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+#endif
+}
+
+int poll_read(socket_type s, state_type state,
+    int msec, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+  fd_set fds;
+  FD_ZERO(&fds);
+  FD_SET(s, &fds);
+  timeval timeout_obj;
+  timeval* timeout;
+  if (state & user_set_non_blocking)
+  {
+    timeout_obj.tv_sec = 0;
+    timeout_obj.tv_usec = 0;
+    timeout = &timeout_obj;
+  }
+  else if (msec >= 0)
+  {
+    timeout_obj.tv_sec = msec / 1000;
+    timeout_obj.tv_usec = (msec % 1000) * 1000;
+    timeout = &timeout_obj;
+  }
+  else
+    timeout = 0;
+  clear_last_error();
+  int result = error_wrapper(::select(s + 1, &fds, 0, 0, timeout), ec);
+#else // defined(ASIO_WINDOWS)
+      // || defined(__CYGWIN__)
+      // || defined(__SYMBIAN32__)
+  pollfd fds;
+  fds.fd = s;
+  fds.events = POLLIN;
+  fds.revents = 0;
+  int timeout = (state & user_set_non_blocking) ? 0 : msec;
+  clear_last_error();
+  int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+#endif // defined(ASIO_WINDOWS)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+  if (result == 0)
+    ec = (state & user_set_non_blocking)
+      ? asio::error::would_block : asio::error_code();
+  else if (result > 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int poll_write(socket_type s, state_type state,
+    int msec, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+  fd_set fds;
+  FD_ZERO(&fds);
+  FD_SET(s, &fds);
+  timeval timeout_obj;
+  timeval* timeout;
+  if (state & user_set_non_blocking)
+  {
+    timeout_obj.tv_sec = 0;
+    timeout_obj.tv_usec = 0;
+    timeout = &timeout_obj;
+  }
+  else if (msec >= 0)
+  {
+    timeout_obj.tv_sec = msec / 1000;
+    timeout_obj.tv_usec = (msec % 1000) * 1000;
+    timeout = &timeout_obj;
+  }
+  else
+    timeout = 0;
+  clear_last_error();
+  int result = error_wrapper(::select(s + 1, 0, &fds, 0, timeout), ec);
+#else // defined(ASIO_WINDOWS)
+      // || defined(__CYGWIN__)
+      // || defined(__SYMBIAN32__)
+  pollfd fds;
+  fds.fd = s;
+  fds.events = POLLOUT;
+  fds.revents = 0;
+  int timeout = (state & user_set_non_blocking) ? 0 : msec;
+  clear_last_error();
+  int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+#endif // defined(ASIO_WINDOWS)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+  if (result == 0)
+    ec = (state & user_set_non_blocking)
+      ? asio::error::would_block : asio::error_code();
+  else if (result > 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int poll_error(socket_type s, state_type state,
+    int msec, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+  fd_set fds;
+  FD_ZERO(&fds);
+  FD_SET(s, &fds);
+  timeval timeout_obj;
+  timeval* timeout;
+  if (state & user_set_non_blocking)
+  {
+    timeout_obj.tv_sec = 0;
+    timeout_obj.tv_usec = 0;
+    timeout = &timeout_obj;
+  }
+  else if (msec >= 0)
+  {
+    timeout_obj.tv_sec = msec / 1000;
+    timeout_obj.tv_usec = (msec % 1000) * 1000;
+    timeout = &timeout_obj;
+  }
+  else
+    timeout = 0;
+  clear_last_error();
+  int result = error_wrapper(::select(s + 1, 0, 0, &fds, timeout), ec);
+#else // defined(ASIO_WINDOWS)
+      // || defined(__CYGWIN__)
+      // || defined(__SYMBIAN32__)
+  pollfd fds;
+  fds.fd = s;
+  fds.events = POLLPRI | POLLERR | POLLHUP;
+  fds.revents = 0;
+  int timeout = (state & user_set_non_blocking) ? 0 : msec;
+  clear_last_error();
+  int result = error_wrapper(::poll(&fds, 1, timeout), ec);
+#endif // defined(ASIO_WINDOWS)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+  if (result == 0)
+    ec = (state & user_set_non_blocking)
+      ? asio::error::would_block : asio::error_code();
+  else if (result > 0)
+    ec = asio::error_code();
+  return result;
+}
+
+int poll_connect(socket_type s, int msec, asio::error_code& ec)
+{
+  if (s == invalid_socket)
+  {
+    ec = asio::error::bad_descriptor;
+    return socket_error_retval;
+  }
+
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+  fd_set write_fds;
+  FD_ZERO(&write_fds);
+  FD_SET(s, &write_fds);
+  fd_set except_fds;
+  FD_ZERO(&except_fds);
+  FD_SET(s, &except_fds);
+  timeval timeout_obj;
+  timeval* timeout;
+  if (msec >= 0)
+  {
+    timeout_obj.tv_sec = msec / 1000;
+    timeout_obj.tv_usec = (msec % 1000) * 1000;
+    timeout = &timeout_obj;
+  }
+  else
+    timeout = 0;
+  clear_last_error();
+  int result = error_wrapper(::select(
+        s + 1, 0, &write_fds, &except_fds, timeout), ec);
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+#else // defined(ASIO_WINDOWS)
+      // || defined(__CYGWIN__)
+      // || defined(__SYMBIAN32__)
+  pollfd fds;
+  fds.fd = s;
+  fds.events = POLLOUT;
+  fds.revents = 0;
+  clear_last_error();
+  int result = error_wrapper(::poll(&fds, 1, msec), ec);
+  if (result >= 0)
+    ec = asio::error_code();
+  return result;
+#endif // defined(ASIO_WINDOWS)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+}
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+const char* inet_ntop(int af, const void* src, char* dest, size_t length,
+    unsigned long scope_id, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS_RUNTIME)
+  using namespace std; // For sprintf.
+  const unsigned char* bytes = static_cast<const unsigned char*>(src);
+  if (af == ASIO_OS_DEF(AF_INET))
+  {
+    sprintf_s(dest, length, "%u.%u.%u.%u",
+        bytes[0], bytes[1], bytes[2], bytes[3]);
+    return dest;
+  }
+  else if (af == ASIO_OS_DEF(AF_INET6))
+  {
+    size_t n = 0, b = 0, z = 0;
+    while (n < length && b < 16)
+    {
+      if (bytes[b] == 0 && bytes[b + 1] == 0 && z == 0)
+      {
+        do b += 2; while (b < 16 && bytes[b] == 0 && bytes[b + 1] == 0);
+        n += sprintf_s(dest + n, length - n, ":%s", b < 16 ? "" : ":"), ++z;
+      }
+      else
+      {
+        n += sprintf_s(dest + n, length - n, "%s%x", b ? ":" : "",
+            (static_cast<u_long_type>(bytes[b]) << 8) | bytes[b + 1]);
+        b += 2;
+      }
+    }
+    if (scope_id)
+      n += sprintf_s(dest + n, length - n, "%%%lu", scope_id);
+    return dest;
+  }
+  else
+  {
+    ec = asio::error::address_family_not_supported;
+    return 0;
+  }
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  using namespace std; // For memcpy.
+
+  if (af != ASIO_OS_DEF(AF_INET) && af != ASIO_OS_DEF(AF_INET6))
+  {
+    ec = asio::error::address_family_not_supported;
+    return 0;
+  }
+
+  union
+  {
+    socket_addr_type base;
+    sockaddr_storage_type storage;
+    sockaddr_in4_type v4;
+    sockaddr_in6_type v6;
+  } address;
+  DWORD address_length;
+  if (af == ASIO_OS_DEF(AF_INET))
+  {
+    address_length = sizeof(sockaddr_in4_type);
+    address.v4.sin_family = ASIO_OS_DEF(AF_INET);
+    address.v4.sin_port = 0;
+    memcpy(&address.v4.sin_addr, src, sizeof(in4_addr_type));
+  }
+  else // AF_INET6
+  {
+    address_length = sizeof(sockaddr_in6_type);
+    address.v6.sin6_family = ASIO_OS_DEF(AF_INET6);
+    address.v6.sin6_port = 0;
+    address.v6.sin6_flowinfo = 0;
+    address.v6.sin6_scope_id = scope_id;
+    memcpy(&address.v6.sin6_addr, src, sizeof(in6_addr_type));
+  }
+
+  DWORD string_length = static_cast<DWORD>(length);
+#if defined(BOOST_NO_ANSI_APIS) || (defined(_MSC_VER) && (_MSC_VER >= 1800))
+  LPWSTR string_buffer = (LPWSTR)_alloca(length * sizeof(WCHAR));
+  int result = error_wrapper(::WSAAddressToStringW(&address.base,
+        address_length, 0, string_buffer, &string_length), ec);
+  ::WideCharToMultiByte(CP_ACP, 0, string_buffer, -1,
+      dest, static_cast<int>(length), 0, 0);
+#else
+  int result = error_wrapper(::WSAAddressToStringA(
+        &address.base, address_length, 0, dest, &string_length), ec);
+#endif
+
+  // Windows may set error code on success.
+  if (result != socket_error_retval)
+    ec = asio::error_code();
+
+  // Windows may not set an error code on failure.
+  else if (result == socket_error_retval && !ec)
+    ec = asio::error::invalid_argument;
+
+  return result == socket_error_retval ? 0 : dest;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  const char* result = error_wrapper(::inet_ntop(
+        af, src, dest, static_cast<int>(length)), ec);
+  if (result == 0 && !ec)
+    ec = asio::error::invalid_argument;
+  if (result != 0 && af == ASIO_OS_DEF(AF_INET6) && scope_id != 0)
+  {
+    using namespace std; // For strcat and sprintf.
+    char if_name[(IF_NAMESIZE > 21 ? IF_NAMESIZE : 21) + 1] = "%";
+    const in6_addr_type* ipv6_address = static_cast<const in6_addr_type*>(src);
+    bool is_link_local = ((ipv6_address->s6_addr[0] == 0xfe)
+        && ((ipv6_address->s6_addr[1] & 0xc0) == 0x80));
+    bool is_multicast_link_local = ((ipv6_address->s6_addr[0] == 0xff)
+        && ((ipv6_address->s6_addr[1] & 0x0f) == 0x02));
+    if ((!is_link_local && !is_multicast_link_local)
+        || if_indextoname(static_cast<unsigned>(scope_id), if_name + 1) == 0)
+      sprintf(if_name + 1, "%lu", scope_id);
+    strcat(dest, if_name);
+  }
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+int inet_pton(int af, const char* src, void* dest,
+    unsigned long* scope_id, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS_RUNTIME)
+  using namespace std; // For sscanf.
+  unsigned char* bytes = static_cast<unsigned char*>(dest);
+  if (af == ASIO_OS_DEF(AF_INET))
+  {
+    unsigned int b0, b1, b2, b3;
+    if (sscanf_s(src, "%u.%u.%u.%u", &b0, &b1, &b2, &b3) != 4)
+    {
+      ec = asio::error::invalid_argument;
+      return -1;
+    }
+    if (b0 > 255 || b1 > 255 || b2 > 255 || b3 > 255)
+    {
+      ec = asio::error::invalid_argument;
+      return -1;
+    }
+    bytes[0] = static_cast<unsigned char>(b0);
+    bytes[1] = static_cast<unsigned char>(b1);
+    bytes[2] = static_cast<unsigned char>(b2);
+    bytes[3] = static_cast<unsigned char>(b3);
+    ec = asio::error_code();
+    return 1;
+  }
+  else if (af == ASIO_OS_DEF(AF_INET6))
+  {
+    unsigned char* bytes = static_cast<unsigned char*>(dest);
+    std::memset(bytes, 0, 16);
+    unsigned char back_bytes[16] = { 0 };
+    int num_front_bytes = 0, num_back_bytes = 0;
+    const char* p = src;
+
+    enum { fword, fcolon, bword, scope, done } state = fword;
+    unsigned long current_word = 0;
+    while (state != done)
+    {
+      if (current_word > 0xFFFF)
+      {
+        ec = asio::error::invalid_argument;
+        return -1;
+      }
+
+      switch (state)
+      {
+      case fword:
+        if (*p >= '0' && *p <= '9')
+          current_word = current_word * 16 + *p++ - '0';
+        else if (*p >= 'a' && *p <= 'f')
+          current_word = current_word * 16 + *p++ - 'a' + 10;
+        else if (*p >= 'A' && *p <= 'F')
+          current_word = current_word * 16 + *p++ - 'A' + 10;
+        else
+        {
+          if (num_front_bytes == 16)
+          {
+            ec = asio::error::invalid_argument;
+            return -1;
+          }
+
+          bytes[num_front_bytes++] = (current_word >> 8) & 0xFF;
+          bytes[num_front_bytes++] = current_word & 0xFF;
+          current_word = 0;
+
+          if (*p == ':')
+            state = fcolon, ++p;
+          else if (*p == '%')
+            state = scope, ++p;
+          else if (*p == 0)
+            state = done;
+          else
+          {
+            ec = asio::error::invalid_argument;
+            return -1;
+          }
+        }
+        break;
+
+      case fcolon:
+        if (*p == ':')
+          state = bword, ++p;
+        else
+          state = fword;
+        break;
+
+      case bword:
+        if (*p >= '0' && *p <= '9')
+          current_word = current_word * 16 + *p++ - '0';
+        else if (*p >= 'a' && *p <= 'f')
+          current_word = current_word * 16 + *p++ - 'a' + 10;
+        else if (*p >= 'A' && *p <= 'F')
+          current_word = current_word * 16 + *p++ - 'A' + 10;
+        else
+        {
+          if (num_front_bytes + num_back_bytes == 16)
+          {
+            ec = asio::error::invalid_argument;
+            return -1;
+          }
+
+          back_bytes[num_back_bytes++] = (current_word >> 8) & 0xFF;
+          back_bytes[num_back_bytes++] = current_word & 0xFF;
+          current_word = 0;
+
+          if (*p == ':')
+            state = bword, ++p;
+          else if (*p == '%')
+            state = scope, ++p;
+          else if (*p == 0)
+            state = done;
+          else
+          {
+            ec = asio::error::invalid_argument;
+            return -1;
+          }
+        }
+        break;
+
+      case scope:
+        if (*p >= '0' && *p <= '9')
+          current_word = current_word * 10 + *p++ - '0';
+        else if (*p == 0)
+          *scope_id = current_word, state = done;
+        else
+        {
+          ec = asio::error::invalid_argument;
+          return -1;
+        }
+        break;
+
+      default:
+        break;
+      }
+    }
+
+    for (int i = 0; i < num_back_bytes; ++i)
+      bytes[16 - num_back_bytes + i] = back_bytes[i];
+
+    ec = asio::error_code();
+    return 1;
+  }
+  else
+  {
+    ec = asio::error::address_family_not_supported;
+    return -1;
+  }
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  using namespace std; // For memcpy and strcmp.
+
+  if (af != ASIO_OS_DEF(AF_INET) && af != ASIO_OS_DEF(AF_INET6))
+  {
+    ec = asio::error::address_family_not_supported;
+    return -1;
+  }
+
+  union
+  {
+    socket_addr_type base;
+    sockaddr_storage_type storage;
+    sockaddr_in4_type v4;
+    sockaddr_in6_type v6;
+  } address;
+  int address_length = sizeof(sockaddr_storage_type);
+#if defined(BOOST_NO_ANSI_APIS) || (defined(_MSC_VER) && (_MSC_VER >= 1800))
+  int num_wide_chars = static_cast<int>(strlen(src)) + 1;
+  LPWSTR wide_buffer = (LPWSTR)_alloca(num_wide_chars * sizeof(WCHAR));
+  ::MultiByteToWideChar(CP_ACP, 0, src, -1, wide_buffer, num_wide_chars);
+  int result = error_wrapper(::WSAStringToAddressW(
+        wide_buffer, af, 0, &address.base, &address_length), ec);
+#else
+  int result = error_wrapper(::WSAStringToAddressA(
+        const_cast<char*>(src), af, 0, &address.base, &address_length), ec);
+#endif
+
+  if (af == ASIO_OS_DEF(AF_INET))
+  {
+    if (result != socket_error_retval)
+    {
+      memcpy(dest, &address.v4.sin_addr, sizeof(in4_addr_type));
+      ec = asio::error_code();
+    }
+    else if (strcmp(src, "255.255.255.255") == 0)
+    {
+      static_cast<in4_addr_type*>(dest)->s_addr = INADDR_NONE;
+      ec = asio::error_code();
+    }
+  }
+  else // AF_INET6
+  {
+    if (result != socket_error_retval)
+    {
+      memcpy(dest, &address.v6.sin6_addr, sizeof(in6_addr_type));
+      if (scope_id)
+        *scope_id = address.v6.sin6_scope_id;
+      ec = asio::error_code();
+    }
+  }
+
+  // Windows may not set an error code on failure.
+  if (result == socket_error_retval && !ec)
+    ec = asio::error::invalid_argument;
+
+  if (result != socket_error_retval)
+    ec = asio::error_code();
+
+  return result == socket_error_retval ? -1 : 1;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  using namespace std; // For strchr, memcpy and atoi.
+
+  // On some platforms, inet_pton fails if an address string contains a scope
+  // id. Detect and remove the scope id before passing the string to inet_pton.
+  const bool is_v6 = (af == ASIO_OS_DEF(AF_INET6));
+  const char* if_name = is_v6 ? strchr(src, '%') : 0;
+  char src_buf[max_addr_v6_str_len + 1];
+  const char* src_ptr = src;
+  if (if_name != 0)
+  {
+    if (if_name - src > max_addr_v6_str_len)
+    {
+      ec = asio::error::invalid_argument;
+      return 0;
+    }
+    memcpy(src_buf, src, if_name - src);
+    src_buf[if_name - src] = 0;
+    src_ptr = src_buf;
+  }
+
+  int result = error_wrapper(::inet_pton(af, src_ptr, dest), ec);
+  if (result <= 0 && !ec)
+    ec = asio::error::invalid_argument;
+  if (result > 0 && is_v6 && scope_id)
+  {
+    using namespace std; // For strchr and atoi.
+    *scope_id = 0;
+    if (if_name != 0)
+    {
+      in6_addr_type* ipv6_address = static_cast<in6_addr_type*>(dest);
+      bool is_link_local = ((ipv6_address->s6_addr[0] == 0xfe)
+          && ((ipv6_address->s6_addr[1] & 0xc0) == 0x80));
+      bool is_multicast_link_local = ((ipv6_address->s6_addr[0] == 0xff)
+          && ((ipv6_address->s6_addr[1] & 0x0f) == 0x02));
+      if (is_link_local || is_multicast_link_local)
+        *scope_id = if_nametoindex(if_name + 1);
+      if (*scope_id == 0)
+        *scope_id = atoi(if_name + 1);
+    }
+  }
+  return result;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+}
+
+int gethostname(char* name, int namelen, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS_RUNTIME)
+  try
+  {
+    using namespace Windows::Foundation::Collections;
+    using namespace Windows::Networking;
+    using namespace Windows::Networking::Connectivity;
+    IVectorView<HostName^>^ hostnames = NetworkInformation::GetHostNames();
+    for (unsigned i = 0; i < hostnames->Size; ++i)
+    {
+      HostName^ hostname = hostnames->GetAt(i);
+      if (hostname->Type == HostNameType::DomainName)
+      {
+        std::wstring_convert<std::codecvt_utf8<wchar_t>> converter;
+        std::string raw_name = converter.to_bytes(hostname->RawName->Data());
+        if (namelen > 0 && raw_name.size() < static_cast<std::size_t>(namelen))
+        {
+          strcpy_s(name, namelen, raw_name.c_str());
+          return 0;
+        }
+      }
+    }
+    return -1;
+  }
+  catch (Platform::Exception^ e)
+  {
+    ec = asio::error_code(e->HResult,
+        asio::system_category());
+    return -1;
+  }
+#else // defined(ASIO_WINDOWS_RUNTIME)
+  int result = error_wrapper(::gethostname(name, namelen), ec);
+# if defined(ASIO_WINDOWS)
+  if (result == 0)
+    ec = asio::error_code();
+# endif // defined(ASIO_WINDOWS)
+  return result;
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+}
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+#if !defined(ASIO_HAS_GETADDRINFO)
+
+// The following functions are only needed for emulation of getaddrinfo and
+// getnameinfo.
+
+inline asio::error_code translate_netdb_error(int error)
+{
+  switch (error)
+  {
+  case 0:
+    return asio::error_code();
+  case HOST_NOT_FOUND:
+    return asio::error::host_not_found;
+  case TRY_AGAIN:
+    return asio::error::host_not_found_try_again;
+  case NO_RECOVERY:
+    return asio::error::no_recovery;
+  case NO_DATA:
+    return asio::error::no_data;
+  default:
+    ASIO_ASSERT(false);
+    return asio::error::invalid_argument;
+  }
+}
+
+inline hostent* gethostbyaddr(const char* addr, int length, int af,
+    hostent* result, char* buffer, int buflength, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  (void)(buffer);
+  (void)(buflength);
+  hostent* retval = error_wrapper(::gethostbyaddr(addr, length, af), ec);
+  if (!retval)
+    return 0;
+  ec = asio::error_code();
+  *result = *retval;
+  return retval;
+#elif defined(__sun) || defined(__QNX__)
+  int error = 0;
+  hostent* retval = error_wrapper(::gethostbyaddr_r(addr, length, af, result,
+        buffer, buflength, &error), ec);
+  if (error)
+    ec = translate_netdb_error(error);
+  return retval;
+#elif defined(__MACH__) && defined(__APPLE__)
+  (void)(buffer);
+  (void)(buflength);
+  int error = 0;
+  hostent* retval = error_wrapper(::getipnodebyaddr(
+        addr, length, af, &error), ec);
+  if (error)
+    ec = translate_netdb_error(error);
+  if (!retval)
+    return 0;
+  *result = *retval;
+  return retval;
+#else
+  hostent* retval = 0;
+  int error = 0;
+  error_wrapper(::gethostbyaddr_r(addr, length, af, result, buffer,
+        buflength, &retval, &error), ec);
+  if (error)
+    ec = translate_netdb_error(error);
+  return retval;
+#endif
+}
+
+inline hostent* gethostbyname(const char* name, int af, struct hostent* result,
+    char* buffer, int buflength, int ai_flags, asio::error_code& ec)
+{
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  (void)(buffer);
+  (void)(buflength);
+  (void)(ai_flags);
+  if (af != ASIO_OS_DEF(AF_INET))
+  {
+    ec = asio::error::address_family_not_supported;
+    return 0;
+  }
+  hostent* retval = error_wrapper(::gethostbyname(name), ec);
+  if (!retval)
+    return 0;
+  ec = asio::error_code();
+  *result = *retval;
+  return result;
+#elif defined(__sun) || defined(__QNX__)
+  (void)(ai_flags);
+  if (af != ASIO_OS_DEF(AF_INET))
+  {
+    ec = asio::error::address_family_not_supported;
+    return 0;
+  }
+  int error = 0;
+  hostent* retval = error_wrapper(::gethostbyname_r(name, result, buffer,
+        buflength, &error), ec);
+  if (error)
+    ec = translate_netdb_error(error);
+  return retval;
+#elif defined(__MACH__) && defined(__APPLE__)
+  (void)(buffer);
+  (void)(buflength);
+  int error = 0;
+  hostent* retval = error_wrapper(::getipnodebyname(
+        name, af, ai_flags, &error), ec);
+  if (error)
+    ec = translate_netdb_error(error);
+  if (!retval)
+    return 0;
+  *result = *retval;
+  return retval;
+#else
+  (void)(ai_flags);
+  if (af != ASIO_OS_DEF(AF_INET))
+  {
+    ec = asio::error::address_family_not_supported;
+    return 0;
+  }
+  hostent* retval = 0;
+  int error = 0;
+  error_wrapper(::gethostbyname_r(name, result,
+        buffer, buflength, &retval, &error), ec);
+  if (error)
+    ec = translate_netdb_error(error);
+  return retval;
+#endif
+}
+
+inline void freehostent(hostent* h)
+{
+#if defined(__MACH__) && defined(__APPLE__)
+  if (h)
+    ::freehostent(h);
+#else
+  (void)(h);
+#endif
+}
+
+// Emulation of getaddrinfo based on implementation in:
+// Stevens, W. R., UNIX Network Programming Vol. 1, 2nd Ed., Prentice-Hall 1998.
+
+struct gai_search
+{
+  const char* host;
+  int family;
+};
+
+inline int gai_nsearch(const char* host,
+    const addrinfo_type* hints, gai_search (&search)[2])
+{
+  int search_count = 0;
+  if (host == 0 || host[0] == '\0')
+  {
+    if (hints->ai_flags & AI_PASSIVE)
+    {
+      // No host and AI_PASSIVE implies wildcard bind.
+      switch (hints->ai_family)
+      {
+      case ASIO_OS_DEF(AF_INET):
+        search[search_count].host = "0.0.0.0";
+        search[search_count].family = ASIO_OS_DEF(AF_INET);
+        ++search_count;
+        break;
+      case ASIO_OS_DEF(AF_INET6):
+        search[search_count].host = "0::0";
+        search[search_count].family = ASIO_OS_DEF(AF_INET6);
+        ++search_count;
+        break;
+      case ASIO_OS_DEF(AF_UNSPEC):
+        search[search_count].host = "0::0";
+        search[search_count].family = ASIO_OS_DEF(AF_INET6);
+        ++search_count;
+        search[search_count].host = "0.0.0.0";
+        search[search_count].family = ASIO_OS_DEF(AF_INET);
+        ++search_count;
+        break;
+      default:
+        break;
+      }
+    }
+    else
+    {
+      // No host and not AI_PASSIVE means connect to local host.
+      switch (hints->ai_family)
+      {
+      case ASIO_OS_DEF(AF_INET):
+        search[search_count].host = "localhost";
+        search[search_count].family = ASIO_OS_DEF(AF_INET);
+        ++search_count;
+        break;
+      case ASIO_OS_DEF(AF_INET6):
+        search[search_count].host = "localhost";
+        search[search_count].family = ASIO_OS_DEF(AF_INET6);
+        ++search_count;
+        break;
+      case ASIO_OS_DEF(AF_UNSPEC):
+        search[search_count].host = "localhost";
+        search[search_count].family = ASIO_OS_DEF(AF_INET6);
+        ++search_count;
+        search[search_count].host = "localhost";
+        search[search_count].family = ASIO_OS_DEF(AF_INET);
+        ++search_count;
+        break;
+      default:
+        break;
+      }
+    }
+  }
+  else
+  {
+    // Host is specified.
+    switch (hints->ai_family)
+    {
+    case ASIO_OS_DEF(AF_INET):
+      search[search_count].host = host;
+      search[search_count].family = ASIO_OS_DEF(AF_INET);
+      ++search_count;
+      break;
+    case ASIO_OS_DEF(AF_INET6):
+      search[search_count].host = host;
+      search[search_count].family = ASIO_OS_DEF(AF_INET6);
+      ++search_count;
+      break;
+    case ASIO_OS_DEF(AF_UNSPEC):
+      search[search_count].host = host;
+      search[search_count].family = ASIO_OS_DEF(AF_INET6);
+      ++search_count;
+      search[search_count].host = host;
+      search[search_count].family = ASIO_OS_DEF(AF_INET);
+      ++search_count;
+      break;
+    default:
+      break;
+    }
+  }
+  return search_count;
+}
+
+template <typename T>
+inline T* gai_alloc(std::size_t size = sizeof(T))
+{
+  using namespace std;
+  T* p = static_cast<T*>(::operator new(size, std::nothrow));
+  if (p)
+    memset(p, 0, size);
+  return p;
+}
+
+inline void gai_free(void* p)
+{
+  ::operator delete(p);
+}
+
+inline void gai_strcpy(char* target, const char* source, std::size_t max_size)
+{
+  using namespace std;
+#if defined(ASIO_HAS_SECURE_RTL)
+  strcpy_s(target, max_size, source);
+#else // defined(ASIO_HAS_SECURE_RTL)
+  *target = 0;
+  if (max_size > 0)
+    strncat(target, source, max_size - 1);
+#endif // defined(ASIO_HAS_SECURE_RTL)
+}
+
+enum { gai_clone_flag = 1 << 30 };
+
+inline int gai_aistruct(addrinfo_type*** next, const addrinfo_type* hints,
+    const void* addr, int family)
+{
+  using namespace std;
+
+  addrinfo_type* ai = gai_alloc<addrinfo_type>();
+  if (ai == 0)
+    return EAI_MEMORY;
+
+  ai->ai_next = 0;
+  **next = ai;
+  *next = &ai->ai_next;
+
+  ai->ai_canonname = 0;
+  ai->ai_socktype = hints->ai_socktype;
+  if (ai->ai_socktype == 0)
+    ai->ai_flags |= gai_clone_flag;
+  ai->ai_protocol = hints->ai_protocol;
+  ai->ai_family = family;
+
+  switch (ai->ai_family)
+  {
+  case ASIO_OS_DEF(AF_INET):
+    {
+      sockaddr_in4_type* sinptr = gai_alloc<sockaddr_in4_type>();
+      if (sinptr == 0)
+        return EAI_MEMORY;
+      sinptr->sin_family = ASIO_OS_DEF(AF_INET);
+      memcpy(&sinptr->sin_addr, addr, sizeof(in4_addr_type));
+      ai->ai_addr = reinterpret_cast<sockaddr*>(sinptr);
+      ai->ai_addrlen = sizeof(sockaddr_in4_type);
+      break;
+    }
+  case ASIO_OS_DEF(AF_INET6):
+    {
+      sockaddr_in6_type* sin6ptr = gai_alloc<sockaddr_in6_type>();
+      if (sin6ptr == 0)
+        return EAI_MEMORY;
+      sin6ptr->sin6_family = ASIO_OS_DEF(AF_INET6);
+      memcpy(&sin6ptr->sin6_addr, addr, sizeof(in6_addr_type));
+      ai->ai_addr = reinterpret_cast<sockaddr*>(sin6ptr);
+      ai->ai_addrlen = sizeof(sockaddr_in6_type);
+      break;
+    }
+  default:
+    break;
+  }
+
+  return 0;
+}
+
+inline addrinfo_type* gai_clone(addrinfo_type* ai)
+{
+  using namespace std;
+
+  addrinfo_type* new_ai = gai_alloc<addrinfo_type>();
+  if (new_ai == 0)
+    return new_ai;
+
+  new_ai->ai_next = ai->ai_next;
+  ai->ai_next = new_ai;
+
+  new_ai->ai_flags = 0;
+  new_ai->ai_family = ai->ai_family;
+  new_ai->ai_socktype = ai->ai_socktype;
+  new_ai->ai_protocol = ai->ai_protocol;
+  new_ai->ai_canonname = 0;
+  new_ai->ai_addrlen = ai->ai_addrlen;
+  new_ai->ai_addr = gai_alloc<sockaddr>(ai->ai_addrlen);
+  memcpy(new_ai->ai_addr, ai->ai_addr, ai->ai_addrlen);
+
+  return new_ai;
+}
+
+inline int gai_port(addrinfo_type* aihead, int port, int socktype)
+{
+  int num_found = 0;
+
+  for (addrinfo_type* ai = aihead; ai; ai = ai->ai_next)
+  {
+    if (ai->ai_flags & gai_clone_flag)
+    {
+      if (ai->ai_socktype != 0)
+      {
+        ai = gai_clone(ai);
+        if (ai == 0)
+          return -1;
+        // ai now points to newly cloned entry.
+      }
+    }
+    else if (ai->ai_socktype != socktype)
+    {
+      // Ignore if mismatch on socket type.
+      continue;
+    }
+
+    ai->ai_socktype = socktype;
+
+    switch (ai->ai_family)
+    {
+    case ASIO_OS_DEF(AF_INET):
+      {
+        sockaddr_in4_type* sinptr =
+          reinterpret_cast<sockaddr_in4_type*>(ai->ai_addr);
+        sinptr->sin_port = port;
+        ++num_found;
+        break;
+      }
+    case ASIO_OS_DEF(AF_INET6):
+      {
+        sockaddr_in6_type* sin6ptr =
+          reinterpret_cast<sockaddr_in6_type*>(ai->ai_addr);
+        sin6ptr->sin6_port = port;
+        ++num_found;
+        break;
+      }
+    default:
+      break;
+    }
+  }
+
+  return num_found;
+}
+
+inline int gai_serv(addrinfo_type* aihead,
+    const addrinfo_type* hints, const char* serv)
+{
+  using namespace std;
+
+  int num_found = 0;
+
+  if (
+#if defined(AI_NUMERICSERV)
+      (hints->ai_flags & AI_NUMERICSERV) ||
+#endif
+      isdigit(static_cast<unsigned char>(serv[0])))
+  {
+    int port = htons(atoi(serv));
+    if (hints->ai_socktype)
+    {
+      // Caller specifies socket type.
+      int rc = gai_port(aihead, port, hints->ai_socktype);
+      if (rc < 0)
+        return EAI_MEMORY;
+      num_found += rc;
+    }
+    else
+    {
+      // Caller does not specify socket type.
+      int rc = gai_port(aihead, port, SOCK_STREAM);
+      if (rc < 0)
+        return EAI_MEMORY;
+      num_found += rc;
+      rc = gai_port(aihead, port, SOCK_DGRAM);
+      if (rc < 0)
+        return EAI_MEMORY;
+      num_found += rc;
+    }
+  }
+  else
+  {
+    // Try service name with TCP first, then UDP.
+    if (hints->ai_socktype == 0 || hints->ai_socktype == SOCK_STREAM)
+    {
+      servent* sptr = getservbyname(serv, "tcp");
+      if (sptr != 0)
+      {
+        int rc = gai_port(aihead, sptr->s_port, SOCK_STREAM);
+        if (rc < 0)
+          return EAI_MEMORY;
+        num_found += rc;
+      }
+    }
+    if (hints->ai_socktype == 0 || hints->ai_socktype == SOCK_DGRAM)
+    {
+      servent* sptr = getservbyname(serv, "udp");
+      if (sptr != 0)
+      {
+        int rc = gai_port(aihead, sptr->s_port, SOCK_DGRAM);
+        if (rc < 0)
+          return EAI_MEMORY;
+        num_found += rc;
+      }
+    }
+  }
+
+  if (num_found == 0)
+  {
+    if (hints->ai_socktype == 0)
+    {
+      // All calls to getservbyname() failed.
+      return EAI_NONAME;
+    }
+    else
+    {
+      // Service not supported for socket type.
+      return EAI_SERVICE;
+    }
+  }
+
+  return 0;
+}
+
+inline int gai_echeck(const char* host, const char* service,
+    int flags, int family, int socktype, int protocol)
+{
+  (void)(flags);
+  (void)(protocol);
+
+  // Host or service must be specified.
+  if (host == 0 || host[0] == '\0')
+    if (service == 0 || service[0] == '\0')
+      return EAI_NONAME;
+
+  // Check combination of family and socket type.
+  switch (family)
+  {
+  case ASIO_OS_DEF(AF_UNSPEC):
+    break;
+  case ASIO_OS_DEF(AF_INET):
+  case ASIO_OS_DEF(AF_INET6):
+    if (service != 0 && service[0] != '\0')
+      if (socktype != 0 && socktype != SOCK_STREAM && socktype != SOCK_DGRAM)
+        return EAI_SOCKTYPE;
+    break;
+  default:
+    return EAI_FAMILY;
+  }
+
+  return 0;
+}
+
+inline void freeaddrinfo_emulation(addrinfo_type* aihead)
+{
+  addrinfo_type* ai = aihead;
+  while (ai)
+  {
+    gai_free(ai->ai_addr);
+    gai_free(ai->ai_canonname);
+    addrinfo_type* ainext = ai->ai_next;
+    gai_free(ai);
+    ai = ainext;
+  }
+}
+
+inline int getaddrinfo_emulation(const char* host, const char* service,
+    const addrinfo_type* hintsp, addrinfo_type** result)
+{
+  // Set up linked list of addrinfo structures.
+  addrinfo_type* aihead = 0;
+  addrinfo_type** ainext = &aihead;
+  char* canon = 0;
+
+  // Supply default hints if not specified by caller.
+  addrinfo_type hints = addrinfo_type();
+  hints.ai_family = ASIO_OS_DEF(AF_UNSPEC);
+  if (hintsp)
+    hints = *hintsp;
+
+  // If the resolution is not specifically for AF_INET6, remove the AI_V4MAPPED
+  // and AI_ALL flags.
+#if defined(AI_V4MAPPED)
+  if (hints.ai_family != ASIO_OS_DEF(AF_INET6))
+    hints.ai_flags &= ~AI_V4MAPPED;
+#endif
+#if defined(AI_ALL)
+  if (hints.ai_family != ASIO_OS_DEF(AF_INET6))
+    hints.ai_flags &= ~AI_ALL;
+#endif
+
+  // Basic error checking.
+  int rc = gai_echeck(host, service, hints.ai_flags, hints.ai_family,
+      hints.ai_socktype, hints.ai_protocol);
+  if (rc != 0)
+  {
+    freeaddrinfo_emulation(aihead);
+    return rc;
+  }
+
+  gai_search search[2];
+  int search_count = gai_nsearch(host, &hints, search);
+  for (gai_search* sptr = search; sptr < search + search_count; ++sptr)
+  {
+    // Check for IPv4 dotted decimal string.
+    in4_addr_type inaddr;
+    asio::error_code ec;
+    if (socket_ops::inet_pton(ASIO_OS_DEF(AF_INET),
+          sptr->host, &inaddr, 0, ec) == 1)
+    {
+      if (hints.ai_family != ASIO_OS_DEF(AF_UNSPEC)
+          && hints.ai_family != ASIO_OS_DEF(AF_INET))
+      {
+        freeaddrinfo_emulation(aihead);
+        gai_free(canon);
+        return EAI_FAMILY;
+      }
+      if (sptr->family == ASIO_OS_DEF(AF_INET))
+      {
+        rc = gai_aistruct(&ainext, &hints, &inaddr, ASIO_OS_DEF(AF_INET));
+        if (rc != 0)
+        {
+          freeaddrinfo_emulation(aihead);
+          gai_free(canon);
+          return rc;
+        }
+      }
+      continue;
+    }
+
+    // Check for IPv6 hex string.
+    in6_addr_type in6addr;
+    if (socket_ops::inet_pton(ASIO_OS_DEF(AF_INET6),
+          sptr->host, &in6addr, 0, ec) == 1)
+    {
+      if (hints.ai_family != ASIO_OS_DEF(AF_UNSPEC)
+          && hints.ai_family != ASIO_OS_DEF(AF_INET6))
+      {
+        freeaddrinfo_emulation(aihead);
+        gai_free(canon);
+        return EAI_FAMILY;
+      }
+      if (sptr->family == ASIO_OS_DEF(AF_INET6))
+      {
+        rc = gai_aistruct(&ainext, &hints, &in6addr,
+            ASIO_OS_DEF(AF_INET6));
+        if (rc != 0)
+        {
+          freeaddrinfo_emulation(aihead);
+          gai_free(canon);
+          return rc;
+        }
+      }
+      continue;
+    }
+
+    // Look up hostname.
+    hostent hent;
+    char hbuf[8192] = "";
+    hostent* hptr = socket_ops::gethostbyname(sptr->host,
+        sptr->family, &hent, hbuf, sizeof(hbuf), hints.ai_flags, ec);
+    if (hptr == 0)
+    {
+      if (search_count == 2)
+      {
+        // Failure is OK if there are multiple searches.
+        continue;
+      }
+      freeaddrinfo_emulation(aihead);
+      gai_free(canon);
+      if (ec == asio::error::host_not_found)
+        return EAI_NONAME;
+      if (ec == asio::error::host_not_found_try_again)
+        return EAI_AGAIN;
+      if (ec == asio::error::no_recovery)
+        return EAI_FAIL;
+      if (ec == asio::error::no_data)
+        return EAI_NONAME;
+      return EAI_NONAME;
+    }
+
+    // Check for address family mismatch if one was specified.
+    if (hints.ai_family != ASIO_OS_DEF(AF_UNSPEC)
+        && hints.ai_family != hptr->h_addrtype)
+    {
+      freeaddrinfo_emulation(aihead);
+      gai_free(canon);
+      socket_ops::freehostent(hptr);
+      return EAI_FAMILY;
+    }
+
+    // Save canonical name first time.
+    if (host != 0 && host[0] != '\0' && hptr->h_name && hptr->h_name[0]
+        && (hints.ai_flags & AI_CANONNAME) && canon == 0)
+    {
+      std::size_t canon_len = strlen(hptr->h_name) + 1;
+      canon = gai_alloc<char>(canon_len);
+      if (canon == 0)
+      {
+        freeaddrinfo_emulation(aihead);
+        socket_ops::freehostent(hptr);
+        return EAI_MEMORY;
+      }
+      gai_strcpy(canon, hptr->h_name, canon_len);
+    }
+
+    // Create an addrinfo structure for each returned address.
+    for (char** ap = hptr->h_addr_list; *ap; ++ap)
+    {
+      rc = gai_aistruct(&ainext, &hints, *ap, hptr->h_addrtype);
+      if (rc != 0)
+      {
+        freeaddrinfo_emulation(aihead);
+        gai_free(canon);
+        socket_ops::freehostent(hptr);
+        return EAI_FAMILY;
+      }
+    }
+
+    socket_ops::freehostent(hptr);
+  }
+
+  // Check if we found anything.
+  if (aihead == 0)
+  {
+    gai_free(canon);
+    return EAI_NONAME;
+  }
+
+  // Return canonical name in first entry.
+  if (host != 0 && host[0] != '\0' && (hints.ai_flags & AI_CANONNAME))
+  {
+    if (canon)
+    {
+      aihead->ai_canonname = canon;
+      canon = 0;
+    }
+    else
+    {
+      std::size_t canonname_len = strlen(search[0].host) + 1;
+      aihead->ai_canonname = gai_alloc<char>(canonname_len);
+      if (aihead->ai_canonname == 0)
+      {
+        freeaddrinfo_emulation(aihead);
+        return EAI_MEMORY;
+      }
+      gai_strcpy(aihead->ai_canonname, search[0].host, canonname_len);
+    }
+  }
+  gai_free(canon);
+
+  // Process the service name.
+  if (service != 0 && service[0] != '\0')
+  {
+    rc = gai_serv(aihead, &hints, service);
+    if (rc != 0)
+    {
+      freeaddrinfo_emulation(aihead);
+      return rc;
+    }
+  }
+
+  // Return result to caller.
+  *result = aihead;
+  return 0;
+}
+
+inline asio::error_code getnameinfo_emulation(
+    const socket_addr_type* sa, std::size_t salen, char* host,
+    std::size_t hostlen, char* serv, std::size_t servlen, int flags,
+    asio::error_code& ec)
+{
+  using namespace std;
+
+  const char* addr;
+  size_t addr_len;
+  unsigned short port;
+  switch (sa->sa_family)
+  {
+  case ASIO_OS_DEF(AF_INET):
+    if (salen != sizeof(sockaddr_in4_type))
+    {
+      return ec = asio::error::invalid_argument;
+    }
+    addr = reinterpret_cast<const char*>(
+        &reinterpret_cast<const sockaddr_in4_type*>(sa)->sin_addr);
+    addr_len = sizeof(in4_addr_type);
+    port = reinterpret_cast<const sockaddr_in4_type*>(sa)->sin_port;
+    break;
+  case ASIO_OS_DEF(AF_INET6):
+    if (salen != sizeof(sockaddr_in6_type))
+    {
+      return ec = asio::error::invalid_argument;
+    }
+    addr = reinterpret_cast<const char*>(
+        &reinterpret_cast<const sockaddr_in6_type*>(sa)->sin6_addr);
+    addr_len = sizeof(in6_addr_type);
+    port = reinterpret_cast<const sockaddr_in6_type*>(sa)->sin6_port;
+    break;
+  default:
+    return ec = asio::error::address_family_not_supported;
+  }
+
+  if (host && hostlen > 0)
+  {
+    if (flags & NI_NUMERICHOST)
+    {
+      if (socket_ops::inet_ntop(sa->sa_family, addr, host, hostlen, 0, ec) == 0)
+      {
+        return ec;
+      }
+    }
+    else
+    {
+      hostent hent;
+      char hbuf[8192] = "";
+      hostent* hptr = socket_ops::gethostbyaddr(addr,
+          static_cast<int>(addr_len), sa->sa_family,
+          &hent, hbuf, sizeof(hbuf), ec);
+      if (hptr && hptr->h_name && hptr->h_name[0] != '\0')
+      {
+        if (flags & NI_NOFQDN)
+        {
+          char* dot = strchr(hptr->h_name, '.');
+          if (dot)
+          {
+            *dot = 0;
+          }
+        }
+        gai_strcpy(host, hptr->h_name, hostlen);
+        socket_ops::freehostent(hptr);
+      }
+      else
+      {
+        socket_ops::freehostent(hptr);
+        if (flags & NI_NAMEREQD)
+        {
+          return ec = asio::error::host_not_found;
+        }
+        if (socket_ops::inet_ntop(sa->sa_family,
+              addr, host, hostlen, 0, ec) == 0)
+        {
+          return ec;
+        }
+      }
+    }
+  }
+
+  if (serv && servlen > 0)
+  {
+    if (flags & NI_NUMERICSERV)
+    {
+      if (servlen < 6)
+      {
+        return ec = asio::error::no_buffer_space;
+      }
+#if defined(ASIO_HAS_SECURE_RTL)
+      sprintf_s(serv, servlen, "%u", ntohs(port));
+#else // defined(ASIO_HAS_SECURE_RTL)
+      sprintf(serv, "%u", ntohs(port));
+#endif // defined(ASIO_HAS_SECURE_RTL)
+    }
+    else
+    {
+#if defined(ASIO_HAS_PTHREADS)
+      static ::pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+      ::pthread_mutex_lock(&mutex);
+#endif // defined(ASIO_HAS_PTHREADS)
+      servent* sptr = ::getservbyport(port, (flags & NI_DGRAM) ? "udp" : 0);
+      if (sptr && sptr->s_name && sptr->s_name[0] != '\0')
+      {
+        gai_strcpy(serv, sptr->s_name, servlen);
+      }
+      else
+      {
+        if (servlen < 6)
+        {
+          return ec = asio::error::no_buffer_space;
+        }
+#if defined(ASIO_HAS_SECURE_RTL)
+        sprintf_s(serv, servlen, "%u", ntohs(port));
+#else // defined(ASIO_HAS_SECURE_RTL)
+        sprintf(serv, "%u", ntohs(port));
+#endif // defined(ASIO_HAS_SECURE_RTL)
+      }
+#if defined(ASIO_HAS_PTHREADS)
+      ::pthread_mutex_unlock(&mutex);
+#endif // defined(ASIO_HAS_PTHREADS)
+    }
+  }
+
+  ec = asio::error_code();
+  return ec;
+}
+
+#endif // !defined(ASIO_HAS_GETADDRINFO)
+
+inline asio::error_code translate_addrinfo_error(int error)
+{
+  switch (error)
+  {
+  case 0:
+    return asio::error_code();
+  case EAI_AGAIN:
+    return asio::error::host_not_found_try_again;
+  case EAI_BADFLAGS:
+    return asio::error::invalid_argument;
+  case EAI_FAIL:
+    return asio::error::no_recovery;
+  case EAI_FAMILY:
+    return asio::error::address_family_not_supported;
+  case EAI_MEMORY:
+    return asio::error::no_memory;
+  case EAI_NONAME:
+#if defined(EAI_ADDRFAMILY)
+  case EAI_ADDRFAMILY:
+#endif
+#if defined(EAI_NODATA) && (EAI_NODATA != EAI_NONAME)
+  case EAI_NODATA:
+#endif
+    return asio::error::host_not_found;
+  case EAI_SERVICE:
+    return asio::error::service_not_found;
+  case EAI_SOCKTYPE:
+    return asio::error::socket_type_not_supported;
+  default: // Possibly the non-portable EAI_SYSTEM.
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    return asio::error_code(
+        WSAGetLastError(), asio::error::get_system_category());
+#else
+    return asio::error_code(
+        errno, asio::error::get_system_category());
+#endif
+  }
+}
+
+asio::error_code getaddrinfo(const char* host,
+    const char* service, const addrinfo_type& hints,
+    addrinfo_type** result, asio::error_code& ec)
+{
+  host = (host && *host) ? host : 0;
+  service = (service && *service) ? service : 0;
+  clear_last_error();
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if defined(ASIO_HAS_GETADDRINFO)
+  // Building for Windows XP, Windows Server 2003, or later.
+  int error = ::getaddrinfo(host, service, &hints, result);
+  return ec = translate_addrinfo_error(error);
+# else
+  // Building for Windows 2000 or earlier.
+  typedef int (WSAAPI *gai_t)(const char*,
+      const char*, const addrinfo_type*, addrinfo_type**);
+  if (HMODULE winsock_module = ::GetModuleHandleA("ws2_32"))
+  {
+    if (gai_t gai = (gai_t)::GetProcAddress(winsock_module, "getaddrinfo"))
+    {
+      int error = gai(host, service, &hints, result);
+      return ec = translate_addrinfo_error(error);
+    }
+  }
+  int error = getaddrinfo_emulation(host, service, &hints, result);
+  return ec = translate_addrinfo_error(error);
+# endif
+#elif !defined(ASIO_HAS_GETADDRINFO)
+  int error = getaddrinfo_emulation(host, service, &hints, result);
+  return ec = translate_addrinfo_error(error);
+#else
+  int error = ::getaddrinfo(host, service, &hints, result);
+#if defined(__MACH__) && defined(__APPLE__)
+  using namespace std; // For isdigit and atoi.
+  if (error == 0 && service && isdigit(static_cast<unsigned char>(service[0])))
+  {
+    u_short_type port = host_to_network_short(atoi(service));
+    for (addrinfo_type* ai = *result; ai; ai = ai->ai_next)
+    {
+      switch (ai->ai_family)
+      {
+      case ASIO_OS_DEF(AF_INET):
+        {
+          sockaddr_in4_type* sinptr =
+            reinterpret_cast<sockaddr_in4_type*>(ai->ai_addr);
+          if (sinptr->sin_port == 0)
+            sinptr->sin_port = port;
+          break;
+        }
+      case ASIO_OS_DEF(AF_INET6):
+        {
+          sockaddr_in6_type* sin6ptr =
+            reinterpret_cast<sockaddr_in6_type*>(ai->ai_addr);
+          if (sin6ptr->sin6_port == 0)
+            sin6ptr->sin6_port = port;
+          break;
+        }
+      default:
+        break;
+      }
+    }
+  }
+#endif
+  return ec = translate_addrinfo_error(error);
+#endif
+}
+
+asio::error_code background_getaddrinfo(
+    const weak_cancel_token_type& cancel_token, const char* host,
+    const char* service, const addrinfo_type& hints,
+    addrinfo_type** result, asio::error_code& ec)
+{
+  if (cancel_token.expired())
+    ec = asio::error::operation_aborted;
+  else
+    socket_ops::getaddrinfo(host, service, hints, result, ec);
+  return ec;
+}
+
+void freeaddrinfo(addrinfo_type* ai)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if defined(ASIO_HAS_GETADDRINFO)
+  // Building for Windows XP, Windows Server 2003, or later.
+  ::freeaddrinfo(ai);
+# else
+  // Building for Windows 2000 or earlier.
+  typedef int (WSAAPI *fai_t)(addrinfo_type*);
+  if (HMODULE winsock_module = ::GetModuleHandleA("ws2_32"))
+  {
+    if (fai_t fai = (fai_t)::GetProcAddress(winsock_module, "freeaddrinfo"))
+    {
+      fai(ai);
+      return;
+    }
+  }
+  freeaddrinfo_emulation(ai);
+# endif
+#elif !defined(ASIO_HAS_GETADDRINFO)
+  freeaddrinfo_emulation(ai);
+#else
+  ::freeaddrinfo(ai);
+#endif
+}
+
+asio::error_code getnameinfo(const socket_addr_type* addr,
+    std::size_t addrlen, char* host, std::size_t hostlen,
+    char* serv, std::size_t servlen, int flags, asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if defined(ASIO_HAS_GETADDRINFO)
+  // Building for Windows XP, Windows Server 2003, or later.
+  clear_last_error();
+  int error = ::getnameinfo(addr, static_cast<socklen_t>(addrlen),
+      host, static_cast<DWORD>(hostlen),
+      serv, static_cast<DWORD>(servlen), flags);
+  return ec = translate_addrinfo_error(error);
+# else
+  // Building for Windows 2000 or earlier.
+  typedef int (WSAAPI *gni_t)(const socket_addr_type*,
+      int, char*, DWORD, char*, DWORD, int);
+  if (HMODULE winsock_module = ::GetModuleHandleA("ws2_32"))
+  {
+    if (gni_t gni = (gni_t)::GetProcAddress(winsock_module, "getnameinfo"))
+    {
+      clear_last_error();
+      int error = gni(addr, static_cast<int>(addrlen),
+          host, static_cast<DWORD>(hostlen),
+          serv, static_cast<DWORD>(servlen), flags);
+      return ec = translate_addrinfo_error(error);
+    }
+  }
+  clear_last_error();
+  return getnameinfo_emulation(addr, addrlen,
+      host, hostlen, serv, servlen, flags, ec);
+# endif
+#elif !defined(ASIO_HAS_GETADDRINFO)
+  using namespace std; // For memcpy.
+  sockaddr_storage_type tmp_addr;
+  memcpy(&tmp_addr, addr, addrlen);
+  addr = reinterpret_cast<socket_addr_type*>(&tmp_addr);
+  clear_last_error();
+  return getnameinfo_emulation(addr, addrlen,
+      host, hostlen, serv, servlen, flags, ec);
+#else
+  clear_last_error();
+  int error = ::getnameinfo(addr, addrlen, host, hostlen, serv, servlen, flags);
+  return ec = translate_addrinfo_error(error);
+#endif
+}
+
+asio::error_code sync_getnameinfo(
+    const socket_addr_type* addr, std::size_t addrlen,
+    char* host, std::size_t hostlen, char* serv,
+    std::size_t servlen, int sock_type, asio::error_code& ec)
+{
+  // First try resolving with the service name. If that fails try resolving
+  // but allow the service to be returned as a number.
+  int flags = (sock_type == SOCK_DGRAM) ? NI_DGRAM : 0;
+  socket_ops::getnameinfo(addr, addrlen, host,
+      hostlen, serv, servlen, flags, ec);
+  if (ec)
+  {
+    socket_ops::getnameinfo(addr, addrlen, host, hostlen,
+        serv, servlen, flags | NI_NUMERICSERV, ec);
+  }
+
+  return ec;
+}
+
+asio::error_code background_getnameinfo(
+    const weak_cancel_token_type& cancel_token,
+    const socket_addr_type* addr, std::size_t addrlen,
+    char* host, std::size_t hostlen, char* serv,
+    std::size_t servlen, int sock_type, asio::error_code& ec)
+{
+  if (cancel_token.expired())
+  {
+    ec = asio::error::operation_aborted;
+  }
+  else
+  {
+    // First try resolving with the service name. If that fails try resolving
+    // but allow the service to be returned as a number.
+    int flags = (sock_type == SOCK_DGRAM) ? NI_DGRAM : 0;
+    socket_ops::getnameinfo(addr, addrlen, host,
+        hostlen, serv, servlen, flags, ec);
+    if (ec)
+    {
+      socket_ops::getnameinfo(addr, addrlen, host, hostlen,
+          serv, servlen, flags | NI_NUMERICSERV, ec);
+    }
+  }
+
+  return ec;
+}
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+u_long_type network_to_host_long(u_long_type value)
+{
+#if defined(ASIO_WINDOWS_RUNTIME)
+  unsigned char* value_p = reinterpret_cast<unsigned char*>(&value);
+  u_long_type result = (static_cast<u_long_type>(value_p[0]) << 24)
+    | (static_cast<u_long_type>(value_p[1]) << 16)
+    | (static_cast<u_long_type>(value_p[2]) << 8)
+    | static_cast<u_long_type>(value_p[3]);
+  return result;
+#else // defined(ASIO_WINDOWS_RUNTIME)
+  return ntohl(value);
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+}
+
+u_long_type host_to_network_long(u_long_type value)
+{
+#if defined(ASIO_WINDOWS_RUNTIME)
+  u_long_type result;
+  unsigned char* result_p = reinterpret_cast<unsigned char*>(&result);
+  result_p[0] = static_cast<unsigned char>((value >> 24) & 0xFF);
+  result_p[1] = static_cast<unsigned char>((value >> 16) & 0xFF);
+  result_p[2] = static_cast<unsigned char>((value >> 8) & 0xFF);
+  result_p[3] = static_cast<unsigned char>(value & 0xFF);
+  return result;
+#else // defined(ASIO_WINDOWS_RUNTIME)
+  return htonl(value);
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+}
+
+u_short_type network_to_host_short(u_short_type value)
+{
+#if defined(ASIO_WINDOWS_RUNTIME)
+  unsigned char* value_p = reinterpret_cast<unsigned char*>(&value);
+  u_short_type result = (static_cast<u_short_type>(value_p[0]) << 8)
+    | static_cast<u_short_type>(value_p[1]);
+  return result;
+#else // defined(ASIO_WINDOWS_RUNTIME)
+  return ntohs(value);
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+}
+
+u_short_type host_to_network_short(u_short_type value)
+{
+#if defined(ASIO_WINDOWS_RUNTIME)
+  u_short_type result;
+  unsigned char* result_p = reinterpret_cast<unsigned char*>(&result);
+  result_p[0] = static_cast<unsigned char>((value >> 8) & 0xFF);
+  result_p[1] = static_cast<unsigned char>(value & 0xFF);
+  return result;
+#else // defined(ASIO_WINDOWS_RUNTIME)
+  return htons(value);
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+}
+
+} // namespace socket_ops
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SOCKET_OPS_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/socket_select_interrupter.ipp b/subprojects/asio/include/asio/detail/impl/socket_select_interrupter.ipp
new file mode 100644
index 000000000..052f2a765
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/socket_select_interrupter.ipp
@@ -0,0 +1,176 @@
+//
+// detail/impl/socket_select_interrupter.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SOCKET_SELECT_INTERRUPTER_IPP
+#define ASIO_DETAIL_IMPL_SOCKET_SELECT_INTERRUPTER_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+
+#include <cstdlib>
+#include "asio/detail/socket_holder.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_select_interrupter.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+socket_select_interrupter::socket_select_interrupter()
+{
+  open_descriptors();
+}
+
+void socket_select_interrupter::open_descriptors()
+{
+  asio::error_code ec;
+  socket_holder acceptor(socket_ops::socket(
+        AF_INET, SOCK_STREAM, IPPROTO_TCP, ec));
+  if (acceptor.get() == invalid_socket)
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  int opt = 1;
+  socket_ops::state_type acceptor_state = 0;
+  socket_ops::setsockopt(acceptor.get(), acceptor_state,
+      SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt), ec);
+
+  using namespace std; // For memset.
+  sockaddr_in4_type addr;
+  std::size_t addr_len = sizeof(addr);
+  memset(&addr, 0, sizeof(addr));
+  addr.sin_family = AF_INET;
+  addr.sin_addr.s_addr = socket_ops::host_to_network_long(INADDR_LOOPBACK);
+  addr.sin_port = 0;
+  if (socket_ops::bind(acceptor.get(), (const socket_addr_type*)&addr,
+        addr_len, ec) == socket_error_retval)
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  if (socket_ops::getsockname(acceptor.get(), (socket_addr_type*)&addr,
+        &addr_len, ec) == socket_error_retval)
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  // Some broken firewalls on Windows will intermittently cause getsockname to
+  // return 0.0.0.0 when the socket is actually bound to 127.0.0.1. We
+  // explicitly specify the target address here to work around this problem.
+  if (addr.sin_addr.s_addr == socket_ops::host_to_network_long(INADDR_ANY))
+    addr.sin_addr.s_addr = socket_ops::host_to_network_long(INADDR_LOOPBACK);
+
+  if (socket_ops::listen(acceptor.get(),
+        SOMAXCONN, ec) == socket_error_retval)
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  socket_holder client(socket_ops::socket(
+        AF_INET, SOCK_STREAM, IPPROTO_TCP, ec));
+  if (client.get() == invalid_socket)
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  if (socket_ops::connect(client.get(), (const socket_addr_type*)&addr,
+        addr_len, ec) == socket_error_retval)
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  socket_holder server(socket_ops::accept(acceptor.get(), 0, 0, ec));
+  if (server.get() == invalid_socket)
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+  
+  ioctl_arg_type non_blocking = 1;
+  socket_ops::state_type client_state = 0;
+  if (socket_ops::ioctl(client.get(), client_state,
+        FIONBIO, &non_blocking, ec))
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  opt = 1;
+  socket_ops::setsockopt(client.get(), client_state,
+      IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt), ec);
+
+  non_blocking = 1;
+  socket_ops::state_type server_state = 0;
+  if (socket_ops::ioctl(server.get(), server_state,
+        FIONBIO, &non_blocking, ec))
+    asio::detail::throw_error(ec, "socket_select_interrupter");
+
+  opt = 1;
+  socket_ops::setsockopt(server.get(), server_state,
+      IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt), ec);
+
+  read_descriptor_ = server.release();
+  write_descriptor_ = client.release();
+}
+
+socket_select_interrupter::~socket_select_interrupter()
+{
+  close_descriptors();
+}
+
+void socket_select_interrupter::close_descriptors()
+{
+  asio::error_code ec;
+  socket_ops::state_type state = socket_ops::internal_non_blocking;
+  if (read_descriptor_ != invalid_socket)
+    socket_ops::close(read_descriptor_, state, true, ec);
+  if (write_descriptor_ != invalid_socket)
+    socket_ops::close(write_descriptor_, state, true, ec);
+}
+
+void socket_select_interrupter::recreate()
+{
+  close_descriptors();
+
+  write_descriptor_ = invalid_socket;
+  read_descriptor_ = invalid_socket;
+
+  open_descriptors();
+}
+
+void socket_select_interrupter::interrupt()
+{
+  char byte = 0;
+  socket_ops::buf b;
+  socket_ops::init_buf(b, &byte, 1);
+  asio::error_code ec;
+  socket_ops::send(write_descriptor_, &b, 1, 0, ec);
+}
+
+bool socket_select_interrupter::reset()
+{
+  char data[1024];
+  socket_ops::buf b;
+  socket_ops::init_buf(b, data, sizeof(data));
+  asio::error_code ec;
+  int bytes_read = socket_ops::recv(read_descriptor_, &b, 1, 0, ec);
+  bool was_interrupted = (bytes_read > 0);
+  while (bytes_read == sizeof(data))
+    bytes_read = socket_ops::recv(read_descriptor_, &b, 1, 0, ec);
+  return was_interrupted;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_IMPL_SOCKET_SELECT_INTERRUPTER_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/strand_executor_service.hpp b/subprojects/asio/include/asio/detail/impl/strand_executor_service.hpp
new file mode 100644
index 000000000..0e18ca05e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/strand_executor_service.hpp
@@ -0,0 +1,179 @@
+//
+// detail/impl/strand_executor_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_STRAND_EXECUTOR_SERVICE_HPP
+#define ASIO_DETAIL_IMPL_STRAND_EXECUTOR_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/call_stack.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/recycling_allocator.hpp"
+#include "asio/executor_work_guard.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Executor>
+class strand_executor_service::invoker
+{
+public:
+  invoker(const implementation_type& impl, Executor& ex)
+    : impl_(impl),
+      work_(ex)
+  {
+  }
+
+  invoker(const invoker& other)
+    : impl_(other.impl_),
+      work_(other.work_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  invoker(invoker&& other)
+    : impl_(ASIO_MOVE_CAST(implementation_type)(other.impl_)),
+      work_(ASIO_MOVE_CAST(executor_work_guard<Executor>)(other.work_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  struct on_invoker_exit
+  {
+    invoker* this_;
+
+    ~on_invoker_exit()
+    {
+      this_->impl_->mutex_->lock();
+      this_->impl_->ready_queue_.push(this_->impl_->waiting_queue_);
+      bool more_handlers = this_->impl_->locked_ =
+        !this_->impl_->ready_queue_.empty();
+      this_->impl_->mutex_->unlock();
+
+      if (more_handlers)
+      {
+        Executor ex(this_->work_.get_executor());
+        recycling_allocator<void> allocator;
+        ex.post(ASIO_MOVE_CAST(invoker)(*this_), allocator);
+      }
+    }
+  };
+
+  void operator()()
+  {
+    // Indicate that this strand is executing on the current thread.
+    call_stack<strand_impl>::context ctx(impl_.get());
+
+    // Ensure the next handler, if any, is scheduled on block exit.
+    on_invoker_exit on_exit = { this };
+    (void)on_exit;
+
+    // Run all ready handlers. No lock is required since the ready queue is
+    // accessed only within the strand.
+    asio::error_code ec;
+    while (scheduler_operation* o = impl_->ready_queue_.front())
+    {
+      impl_->ready_queue_.pop();
+      o->complete(impl_.get(), ec, 0);
+    }
+  }
+
+private:
+  implementation_type impl_;
+  executor_work_guard<Executor> work_;
+};
+
+template <typename Executor, typename Function, typename Allocator>
+void strand_executor_service::dispatch(const implementation_type& impl,
+    Executor& ex, ASIO_MOVE_ARG(Function) function, const Allocator& a)
+{
+  typedef typename decay<Function>::type function_type;
+
+  // If we are already in the strand then the function can run immediately.
+  if (call_stack<strand_impl>::contains(impl.get()))
+  {
+    // Make a local, non-const copy of the function.
+    function_type tmp(ASIO_MOVE_CAST(Function)(function));
+
+    fenced_block b(fenced_block::full);
+    asio_handler_invoke_helpers::invoke(tmp, tmp);
+    return;
+  }
+
+  // Allocate and construct an operation to wrap the function.
+  typedef executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(function), a);
+
+  ASIO_HANDLER_CREATION((impl->service_->context(), *p.p,
+        "strand_executor", impl.get(), 0, "dispatch"));
+
+  // Add the function to the strand and schedule the strand if required.
+  bool first = enqueue(impl, p.p);
+  p.v = p.p = 0;
+  if (first)
+    ex.dispatch(invoker<Executor>(impl, ex), a);
+}
+
+// Request invocation of the given function and return immediately.
+template <typename Executor, typename Function, typename Allocator>
+void strand_executor_service::post(const implementation_type& impl,
+    Executor& ex, ASIO_MOVE_ARG(Function) function, const Allocator& a)
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Allocate and construct an operation to wrap the function.
+  typedef executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(function), a);
+
+  ASIO_HANDLER_CREATION((impl->service_->context(), *p.p,
+        "strand_executor", impl.get(), 0, "post"));
+
+  // Add the function to the strand and schedule the strand if required.
+  bool first = enqueue(impl, p.p);
+  p.v = p.p = 0;
+  if (first)
+    ex.post(invoker<Executor>(impl, ex), a);
+}
+
+// Request invocation of the given function and return immediately.
+template <typename Executor, typename Function, typename Allocator>
+void strand_executor_service::defer(const implementation_type& impl,
+    Executor& ex, ASIO_MOVE_ARG(Function) function, const Allocator& a)
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Allocate and construct an operation to wrap the function.
+  typedef executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(function), a);
+
+  ASIO_HANDLER_CREATION((impl->service_->context(), *p.p,
+        "strand_executor", impl.get(), 0, "defer"));
+
+  // Add the function to the strand and schedule the strand if required.
+  bool first = enqueue(impl, p.p);
+  p.v = p.p = 0;
+  if (first)
+    ex.defer(invoker<Executor>(impl, ex), a);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_STRAND_EXECUTOR_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/strand_executor_service.ipp b/subprojects/asio/include/asio/detail/impl/strand_executor_service.ipp
new file mode 100644
index 000000000..365652ece
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/strand_executor_service.ipp
@@ -0,0 +1,134 @@
+//
+// detail/impl/strand_executor_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_STRAND_EXECUTOR_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_STRAND_EXECUTOR_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/strand_executor_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+strand_executor_service::strand_executor_service(execution_context& ctx)
+  : execution_context_service_base<strand_executor_service>(ctx),
+    mutex_(),
+    salt_(0),
+    impl_list_(0)
+{
+}
+
+void strand_executor_service::shutdown()
+{
+  op_queue<scheduler_operation> ops;
+
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  strand_impl* impl = impl_list_;
+  while (impl)
+  {
+    impl->mutex_->lock();
+    impl->shutdown_ = true;
+    ops.push(impl->waiting_queue_);
+    ops.push(impl->ready_queue_);
+    impl->mutex_->unlock();
+    impl = impl->next_;
+  }
+}
+
+strand_executor_service::implementation_type
+strand_executor_service::create_implementation()
+{
+  implementation_type new_impl(new strand_impl);
+  new_impl->locked_ = false;
+  new_impl->shutdown_ = false;
+
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // Select a mutex from the pool of shared mutexes.
+  std::size_t salt = salt_++;
+  std::size_t mutex_index = reinterpret_cast<std::size_t>(new_impl.get());
+  mutex_index += (reinterpret_cast<std::size_t>(new_impl.get()) >> 3);
+  mutex_index ^= salt + 0x9e3779b9 + (mutex_index << 6) + (mutex_index >> 2);
+  mutex_index = mutex_index % num_mutexes;
+  if (!mutexes_[mutex_index].get())
+    mutexes_[mutex_index].reset(new mutex);
+  new_impl->mutex_ = mutexes_[mutex_index].get();
+
+  // Insert implementation into linked list of all implementations.
+  new_impl->next_ = impl_list_;
+  new_impl->prev_ = 0;
+  if (impl_list_)
+    impl_list_->prev_ = new_impl.get();
+  impl_list_ = new_impl.get();
+  new_impl->service_ = this;
+
+  return new_impl;
+}
+
+strand_executor_service::strand_impl::~strand_impl()
+{
+  asio::detail::mutex::scoped_lock lock(service_->mutex_);
+
+  // Remove implementation from linked list of all implementations.
+  if (service_->impl_list_ == this)
+    service_->impl_list_ = next_;
+  if (prev_)
+    prev_->next_ = next_;
+  if (next_)
+    next_->prev_= prev_;
+}
+
+bool strand_executor_service::enqueue(const implementation_type& impl,
+    scheduler_operation* op)
+{
+  impl->mutex_->lock();
+  if (impl->shutdown_)
+  {
+    impl->mutex_->unlock();
+    op->destroy();
+    return false;
+  }
+  else if (impl->locked_)
+  {
+    // Some other function already holds the strand lock. Enqueue for later.
+    impl->waiting_queue_.push(op);
+    impl->mutex_->unlock();
+    return false;
+  }
+  else
+  {
+    // The function is acquiring the strand lock and so is responsible for
+    // scheduling the strand.
+    impl->locked_ = true;
+    impl->mutex_->unlock();
+    impl->ready_queue_.push(op);
+    return true;
+  }
+}
+
+bool strand_executor_service::running_in_this_thread(
+    const implementation_type& impl)
+{
+  return !!call_stack<strand_impl>::contains(impl.get());
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_STRAND_EXECUTOR_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/strand_service.hpp b/subprojects/asio/include/asio/detail/impl/strand_service.hpp
new file mode 100644
index 000000000..da5b71694
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/strand_service.hpp
@@ -0,0 +1,118 @@
+//
+// detail/impl/strand_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_STRAND_SERVICE_HPP
+#define ASIO_DETAIL_IMPL_STRAND_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/call_stack.hpp"
+#include "asio/detail/completion_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+inline strand_service::strand_impl::strand_impl()
+  : operation(&strand_service::do_complete),
+    locked_(false)
+{
+}
+
+struct strand_service::on_dispatch_exit
+{
+  io_context_impl* io_context_;
+  strand_impl* impl_;
+
+  ~on_dispatch_exit()
+  {
+    impl_->mutex_.lock();
+    impl_->ready_queue_.push(impl_->waiting_queue_);
+    bool more_handlers = impl_->locked_ = !impl_->ready_queue_.empty();
+    impl_->mutex_.unlock();
+
+    if (more_handlers)
+      io_context_->post_immediate_completion(impl_, false);
+  }
+};
+
+template <typename Handler>
+void strand_service::dispatch(strand_service::implementation_type& impl,
+    Handler& handler)
+{
+  // If we are already in the strand then the handler can run immediately.
+  if (call_stack<strand_impl>::contains(impl))
+  {
+    fenced_block b(fenced_block::full);
+    asio_handler_invoke_helpers::invoke(handler, handler);
+    return;
+  }
+
+  // Allocate and construct an operation to wrap the handler.
+  typedef completion_handler<Handler> op;
+  typename op::ptr p = { asio::detail::addressof(handler),
+    op::ptr::allocate(handler), 0 };
+  p.p = new (p.v) op(handler);
+
+  ASIO_HANDLER_CREATION((this->context(),
+        *p.p, "strand", impl, 0, "dispatch"));
+
+  bool dispatch_immediately = do_dispatch(impl, p.p);
+  operation* o = p.p;
+  p.v = p.p = 0;
+
+  if (dispatch_immediately)
+  {
+    // Indicate that this strand is executing on the current thread.
+    call_stack<strand_impl>::context ctx(impl);
+
+    // Ensure the next handler, if any, is scheduled on block exit.
+    on_dispatch_exit on_exit = { &io_context_, impl };
+    (void)on_exit;
+
+    completion_handler<Handler>::do_complete(
+        &io_context_, o, asio::error_code(), 0);
+  }
+}
+
+// Request the io_context to invoke the given handler and return immediately.
+template <typename Handler>
+void strand_service::post(strand_service::implementation_type& impl,
+    Handler& handler)
+{
+  bool is_continuation =
+    asio_handler_cont_helpers::is_continuation(handler);
+
+  // Allocate and construct an operation to wrap the handler.
+  typedef completion_handler<Handler> op;
+  typename op::ptr p = { asio::detail::addressof(handler),
+    op::ptr::allocate(handler), 0 };
+  p.p = new (p.v) op(handler);
+
+  ASIO_HANDLER_CREATION((this->context(),
+        *p.p, "strand", impl, 0, "post"));
+
+  do_post(impl, p.p, is_continuation);
+  p.v = p.p = 0;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_STRAND_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/strand_service.ipp b/subprojects/asio/include/asio/detail/impl/strand_service.ipp
new file mode 100644
index 000000000..cbaf25b35
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/strand_service.ipp
@@ -0,0 +1,177 @@
+//
+// detail/impl/strand_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_STRAND_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_STRAND_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/call_stack.hpp"
+#include "asio/detail/strand_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct strand_service::on_do_complete_exit
+{
+  io_context_impl* owner_;
+  strand_impl* impl_;
+
+  ~on_do_complete_exit()
+  {
+    impl_->mutex_.lock();
+    impl_->ready_queue_.push(impl_->waiting_queue_);
+    bool more_handlers = impl_->locked_ = !impl_->ready_queue_.empty();
+    impl_->mutex_.unlock();
+
+    if (more_handlers)
+      owner_->post_immediate_completion(impl_, true);
+  }
+};
+
+strand_service::strand_service(asio::io_context& io_context)
+  : asio::detail::service_base<strand_service>(io_context),
+    io_context_(asio::use_service<io_context_impl>(io_context)),
+    mutex_(),
+    salt_(0)
+{
+}
+
+void strand_service::shutdown()
+{
+  op_queue<operation> ops;
+
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  for (std::size_t i = 0; i < num_implementations; ++i)
+  {
+    if (strand_impl* impl = implementations_[i].get())
+    {
+      ops.push(impl->waiting_queue_);
+      ops.push(impl->ready_queue_);
+    }
+  }
+}
+
+void strand_service::construct(strand_service::implementation_type& impl)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  std::size_t salt = salt_++;
+#if defined(ASIO_ENABLE_SEQUENTIAL_STRAND_ALLOCATION)
+  std::size_t index = salt;
+#else // defined(ASIO_ENABLE_SEQUENTIAL_STRAND_ALLOCATION)
+  std::size_t index = reinterpret_cast<std::size_t>(&impl);
+  index += (reinterpret_cast<std::size_t>(&impl) >> 3);
+  index ^= salt + 0x9e3779b9 + (index << 6) + (index >> 2);
+#endif // defined(ASIO_ENABLE_SEQUENTIAL_STRAND_ALLOCATION)
+  index = index % num_implementations;
+
+  if (!implementations_[index].get())
+    implementations_[index].reset(new strand_impl);
+  impl = implementations_[index].get();
+}
+
+bool strand_service::running_in_this_thread(
+    const implementation_type& impl) const
+{
+  return call_stack<strand_impl>::contains(impl) != 0;
+}
+
+bool strand_service::do_dispatch(implementation_type& impl, operation* op)
+{
+  // If we are running inside the io_context, and no other handler already
+  // holds the strand lock, then the handler can run immediately.
+  bool can_dispatch = io_context_.can_dispatch();
+  impl->mutex_.lock();
+  if (can_dispatch && !impl->locked_)
+  {
+    // Immediate invocation is allowed.
+    impl->locked_ = true;
+    impl->mutex_.unlock();
+    return true;
+  }
+
+  if (impl->locked_)
+  {
+    // Some other handler already holds the strand lock. Enqueue for later.
+    impl->waiting_queue_.push(op);
+    impl->mutex_.unlock();
+  }
+  else
+  {
+    // The handler is acquiring the strand lock and so is responsible for
+    // scheduling the strand.
+    impl->locked_ = true;
+    impl->mutex_.unlock();
+    impl->ready_queue_.push(op);
+    io_context_.post_immediate_completion(impl, false);
+  }
+
+  return false;
+}
+
+void strand_service::do_post(implementation_type& impl,
+    operation* op, bool is_continuation)
+{
+  impl->mutex_.lock();
+  if (impl->locked_)
+  {
+    // Some other handler already holds the strand lock. Enqueue for later.
+    impl->waiting_queue_.push(op);
+    impl->mutex_.unlock();
+  }
+  else
+  {
+    // The handler is acquiring the strand lock and so is responsible for
+    // scheduling the strand.
+    impl->locked_ = true;
+    impl->mutex_.unlock();
+    impl->ready_queue_.push(op);
+    io_context_.post_immediate_completion(impl, is_continuation);
+  }
+}
+
+void strand_service::do_complete(void* owner, operation* base,
+    const asio::error_code& ec, std::size_t /*bytes_transferred*/)
+{
+  if (owner)
+  {
+    strand_impl* impl = static_cast<strand_impl*>(base);
+
+    // Indicate that this strand is executing on the current thread.
+    call_stack<strand_impl>::context ctx(impl);
+
+    // Ensure the next handler, if any, is scheduled on block exit.
+    on_do_complete_exit on_exit;
+    on_exit.owner_ = static_cast<io_context_impl*>(owner);
+    on_exit.impl_ = impl;
+
+    // Run all ready handlers. No lock is required since the ready queue is
+    // accessed only within the strand.
+    while (operation* o = impl->ready_queue_.front())
+    {
+      impl->ready_queue_.pop();
+      o->complete(owner, ec, 0);
+    }
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_STRAND_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/throw_error.ipp b/subprojects/asio/include/asio/detail/impl/throw_error.ipp
new file mode 100644
index 000000000..a540cd20d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/throw_error.ipp
@@ -0,0 +1,60 @@
+//
+// detail/impl/throw_error.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_THROW_ERROR_IPP
+#define ASIO_DETAIL_IMPL_THROW_ERROR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/system_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+void do_throw_error(const asio::error_code& err)
+{
+  asio::system_error e(err);
+  asio::detail::throw_exception(e);
+}
+
+void do_throw_error(const asio::error_code& err, const char* location)
+{
+  // boostify: non-boost code starts here
+#if defined(ASIO_MSVC) && defined(ASIO_HAS_STD_SYSTEM_ERROR)
+  // Microsoft's implementation of std::system_error is non-conformant in that
+  // it ignores the error code's message when a "what" string is supplied. We'll
+  // work around this by explicitly formatting the "what" string.
+  std::string what_msg = location;
+  what_msg += ": ";
+  what_msg += err.message();
+  asio::system_error e(err, what_msg);
+  asio::detail::throw_exception(e);
+#else // defined(ASIO_MSVC) && defined(ASIO_HAS_STD_SYSTEM_ERROR)
+  // boostify: non-boost code ends here
+  asio::system_error e(err, location);
+  asio::detail::throw_exception(e);
+  // boostify: non-boost code starts here
+#endif // defined(ASIO_MSVC) && defined(ASIO_HAS_STD_SYSTEM_ERROR)
+  // boostify: non-boost code ends here
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_THROW_ERROR_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/timer_queue_ptime.ipp b/subprojects/asio/include/asio/detail/impl/timer_queue_ptime.ipp
new file mode 100644
index 000000000..742837f84
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/timer_queue_ptime.ipp
@@ -0,0 +1,91 @@
+//
+// detail/impl/timer_queue_ptime.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_TIMER_QUEUE_PTIME_IPP
+#define ASIO_DETAIL_IMPL_TIMER_QUEUE_PTIME_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#include "asio/detail/timer_queue_ptime.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+timer_queue<time_traits<boost::posix_time::ptime> >::timer_queue()
+{
+}
+
+timer_queue<time_traits<boost::posix_time::ptime> >::~timer_queue()
+{
+}
+
+bool timer_queue<time_traits<boost::posix_time::ptime> >::enqueue_timer(
+    const time_type& time, per_timer_data& timer, wait_op* op)
+{
+  return impl_.enqueue_timer(time, timer, op);
+}
+
+bool timer_queue<time_traits<boost::posix_time::ptime> >::empty() const
+{
+  return impl_.empty();
+}
+
+long timer_queue<time_traits<boost::posix_time::ptime> >::wait_duration_msec(
+    long max_duration) const
+{
+  return impl_.wait_duration_msec(max_duration);
+}
+
+long timer_queue<time_traits<boost::posix_time::ptime> >::wait_duration_usec(
+    long max_duration) const
+{
+  return impl_.wait_duration_usec(max_duration);
+}
+
+void timer_queue<time_traits<boost::posix_time::ptime> >::get_ready_timers(
+    op_queue<operation>& ops)
+{
+  impl_.get_ready_timers(ops);
+}
+
+void timer_queue<time_traits<boost::posix_time::ptime> >::get_all_timers(
+    op_queue<operation>& ops)
+{
+  impl_.get_all_timers(ops);
+}
+
+std::size_t timer_queue<time_traits<boost::posix_time::ptime> >::cancel_timer(
+    per_timer_data& timer, op_queue<operation>& ops, std::size_t max_cancelled)
+{
+  return impl_.cancel_timer(timer, ops, max_cancelled);
+}
+
+void timer_queue<time_traits<boost::posix_time::ptime> >::move_timer(
+    per_timer_data& target, per_timer_data& source)
+{
+  impl_.move_timer(target, source);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#endif // ASIO_DETAIL_IMPL_TIMER_QUEUE_PTIME_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/timer_queue_set.ipp b/subprojects/asio/include/asio/detail/impl/timer_queue_set.ipp
new file mode 100644
index 000000000..b51654883
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/timer_queue_set.ipp
@@ -0,0 +1,101 @@
+//
+// detail/impl/timer_queue_set.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_TIMER_QUEUE_SET_IPP
+#define ASIO_DETAIL_IMPL_TIMER_QUEUE_SET_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/timer_queue_set.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+timer_queue_set::timer_queue_set()
+  : first_(0)
+{
+}
+
+void timer_queue_set::insert(timer_queue_base* q)
+{
+  q->next_ = first_;
+  first_ = q;
+}
+
+void timer_queue_set::erase(timer_queue_base* q)
+{
+  if (first_)
+  {
+    if (q == first_)
+    {
+      first_ = q->next_;
+      q->next_ = 0;
+      return;
+    }
+
+    for (timer_queue_base* p = first_; p->next_; p = p->next_)
+    {
+      if (p->next_ == q)
+      {
+        p->next_ = q->next_;
+        q->next_ = 0;
+        return;
+      }
+    }
+  }
+}
+
+bool timer_queue_set::all_empty() const
+{
+  for (timer_queue_base* p = first_; p; p = p->next_)
+    if (!p->empty())
+      return false;
+  return true;
+}
+
+long timer_queue_set::wait_duration_msec(long max_duration) const
+{
+  long min_duration = max_duration;
+  for (timer_queue_base* p = first_; p; p = p->next_)
+    min_duration = p->wait_duration_msec(min_duration);
+  return min_duration;
+}
+
+long timer_queue_set::wait_duration_usec(long max_duration) const
+{
+  long min_duration = max_duration;
+  for (timer_queue_base* p = first_; p; p = p->next_)
+    min_duration = p->wait_duration_usec(min_duration);
+  return min_duration;
+}
+
+void timer_queue_set::get_ready_timers(op_queue<operation>& ops)
+{
+  for (timer_queue_base* p = first_; p; p = p->next_)
+    p->get_ready_timers(ops);
+}
+
+void timer_queue_set::get_all_timers(op_queue<operation>& ops)
+{
+  for (timer_queue_base* p = first_; p; p = p->next_)
+    p->get_all_timers(ops);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_TIMER_QUEUE_SET_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_event.ipp b/subprojects/asio/include/asio/detail/impl/win_event.ipp
new file mode 100644
index 000000000..6f7464991
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_event.ipp
@@ -0,0 +1,76 @@
+//
+// detail/win_event.ipp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_EVENT_IPP
+#define ASIO_DETAIL_IMPL_WIN_EVENT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_event.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+win_event::win_event()
+  : state_(0)
+{
+#if defined(ASIO_WINDOWS_APP)
+  events_[0] = ::CreateEventExW(0, 0,
+      CREATE_EVENT_MANUAL_RESET, EVENT_ALL_ACCESS);
+#else // defined(ASIO_WINDOWS_APP)
+  events_[0] = ::CreateEventW(0, true, false, 0);
+#endif // defined(ASIO_WINDOWS_APP)
+  if (!events_[0])
+  {
+    DWORD last_error = ::GetLastError();
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "event");
+  }
+
+#if defined(ASIO_WINDOWS_APP)
+  events_[1] = ::CreateEventExW(0, 0, 0, EVENT_ALL_ACCESS);
+#else // defined(ASIO_WINDOWS_APP)
+  events_[1] = ::CreateEventW(0, false, false, 0);
+#endif // defined(ASIO_WINDOWS_APP)
+  if (!events_[1])
+  {
+    DWORD last_error = ::GetLastError();
+    ::CloseHandle(events_[0]);
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "event");
+  }
+}
+
+win_event::~win_event()
+{
+  ::CloseHandle(events_[0]);
+  ::CloseHandle(events_[1]);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_IMPL_WIN_EVENT_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_iocp_handle_service.ipp b/subprojects/asio/include/asio/detail/impl/win_iocp_handle_service.ipp
new file mode 100644
index 000000000..9cba2b0fc
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_iocp_handle_service.ipp
@@ -0,0 +1,525 @@
+//
+// detail/impl/win_iocp_handle_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_IOCP_HANDLE_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_WIN_IOCP_HANDLE_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/win_iocp_handle_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_iocp_handle_service::overlapped_wrapper
+  : public OVERLAPPED
+{
+public:
+  explicit overlapped_wrapper(asio::error_code& ec)
+  {
+    Internal = 0;
+    InternalHigh = 0;
+    Offset = 0;
+    OffsetHigh = 0;
+
+    // Create a non-signalled manual-reset event, for GetOverlappedResult.
+    hEvent = ::CreateEventW(0, TRUE, FALSE, 0);
+    if (hEvent)
+    {
+      // As documented in GetQueuedCompletionStatus, setting the low order
+      // bit of this event prevents our synchronous writes from being treated
+      // as completion port events.
+      DWORD_PTR tmp = reinterpret_cast<DWORD_PTR>(hEvent);
+      hEvent = reinterpret_cast<HANDLE>(tmp | 1);
+    }
+    else
+    {
+      DWORD last_error = ::GetLastError();
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+    }
+  }
+
+  ~overlapped_wrapper()
+  {
+    if (hEvent)
+    {
+      ::CloseHandle(hEvent);
+    }
+  }
+};
+
+win_iocp_handle_service::win_iocp_handle_service(
+    asio::io_context& io_context)
+  : service_base<win_iocp_handle_service>(io_context),
+    iocp_service_(asio::use_service<win_iocp_io_context>(io_context)),
+    mutex_(),
+    impl_list_(0)
+{
+}
+
+void win_iocp_handle_service::shutdown()
+{
+  // Close all implementations, causing all operations to complete.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  implementation_type* impl = impl_list_;
+  while (impl)
+  {
+    close_for_destruction(*impl);
+    impl = impl->next_;
+  }
+}
+
+void win_iocp_handle_service::construct(
+    win_iocp_handle_service::implementation_type& impl)
+{
+  impl.handle_ = INVALID_HANDLE_VALUE;
+  impl.safe_cancellation_thread_id_ = 0;
+
+  // Insert implementation into linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  impl.next_ = impl_list_;
+  impl.prev_ = 0;
+  if (impl_list_)
+    impl_list_->prev_ = &impl;
+  impl_list_ = &impl;
+}
+
+void win_iocp_handle_service::move_construct(
+    win_iocp_handle_service::implementation_type& impl,
+    win_iocp_handle_service::implementation_type& other_impl)
+{
+  impl.handle_ = other_impl.handle_;
+  other_impl.handle_ = INVALID_HANDLE_VALUE;
+
+  impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_;
+  other_impl.safe_cancellation_thread_id_ = 0;
+
+  // Insert implementation into linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  impl.next_ = impl_list_;
+  impl.prev_ = 0;
+  if (impl_list_)
+    impl_list_->prev_ = &impl;
+  impl_list_ = &impl;
+}
+
+void win_iocp_handle_service::move_assign(
+    win_iocp_handle_service::implementation_type& impl,
+    win_iocp_handle_service& other_service,
+    win_iocp_handle_service::implementation_type& other_impl)
+{
+  close_for_destruction(impl);
+
+  if (this != &other_service)
+  {
+    // Remove implementation from linked list of all implementations.
+    asio::detail::mutex::scoped_lock lock(mutex_);
+    if (impl_list_ == &impl)
+      impl_list_ = impl.next_;
+    if (impl.prev_)
+      impl.prev_->next_ = impl.next_;
+    if (impl.next_)
+      impl.next_->prev_= impl.prev_;
+    impl.next_ = 0;
+    impl.prev_ = 0;
+  }
+
+  impl.handle_ = other_impl.handle_;
+  other_impl.handle_ = INVALID_HANDLE_VALUE;
+
+  impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_;
+  other_impl.safe_cancellation_thread_id_ = 0;
+
+  if (this != &other_service)
+  {
+    // Insert implementation into linked list of all implementations.
+    asio::detail::mutex::scoped_lock lock(other_service.mutex_);
+    impl.next_ = other_service.impl_list_;
+    impl.prev_ = 0;
+    if (other_service.impl_list_)
+      other_service.impl_list_->prev_ = &impl;
+    other_service.impl_list_ = &impl;
+  }
+}
+
+void win_iocp_handle_service::destroy(
+    win_iocp_handle_service::implementation_type& impl)
+{
+  close_for_destruction(impl);
+  
+  // Remove implementation from linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  if (impl_list_ == &impl)
+    impl_list_ = impl.next_;
+  if (impl.prev_)
+    impl.prev_->next_ = impl.next_;
+  if (impl.next_)
+    impl.next_->prev_= impl.prev_;
+  impl.next_ = 0;
+  impl.prev_ = 0;
+}
+
+asio::error_code win_iocp_handle_service::assign(
+    win_iocp_handle_service::implementation_type& impl,
+    const native_handle_type& handle, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  if (iocp_service_.register_handle(handle, ec))
+    return ec;
+
+  impl.handle_ = handle;
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code win_iocp_handle_service::close(
+    win_iocp_handle_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((iocp_service_.context(), "handle",
+          &impl, reinterpret_cast<uintmax_t>(impl.handle_), "close"));
+
+    if (!::CloseHandle(impl.handle_))
+    {
+      DWORD last_error = ::GetLastError();
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+    }
+    else
+    {
+      ec = asio::error_code();
+    }
+
+    impl.handle_ = INVALID_HANDLE_VALUE;
+    impl.safe_cancellation_thread_id_ = 0;
+  }
+  else
+  {
+    ec = asio::error_code();
+  }
+
+  return ec;
+}
+
+asio::error_code win_iocp_handle_service::cancel(
+    win_iocp_handle_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return ec;
+  }
+
+  ASIO_HANDLER_OPERATION((iocp_service_.context(), "handle",
+        &impl, reinterpret_cast<uintmax_t>(impl.handle_), "cancel"));
+
+  if (FARPROC cancel_io_ex_ptr = ::GetProcAddress(
+        ::GetModuleHandleA("KERNEL32"), "CancelIoEx"))
+  {
+    // The version of Windows supports cancellation from any thread.
+    typedef BOOL (WINAPI* cancel_io_ex_t)(HANDLE, LPOVERLAPPED);
+    cancel_io_ex_t cancel_io_ex = (cancel_io_ex_t)cancel_io_ex_ptr;
+    if (!cancel_io_ex(impl.handle_, 0))
+    {
+      DWORD last_error = ::GetLastError();
+      if (last_error == ERROR_NOT_FOUND)
+      {
+        // ERROR_NOT_FOUND means that there were no operations to be
+        // cancelled. We swallow this error to match the behaviour on other
+        // platforms.
+        ec = asio::error_code();
+      }
+      else
+      {
+        ec = asio::error_code(last_error,
+            asio::error::get_system_category());
+      }
+    }
+    else
+    {
+      ec = asio::error_code();
+    }
+  }
+  else if (impl.safe_cancellation_thread_id_ == 0)
+  {
+    // No operations have been started, so there's nothing to cancel.
+    ec = asio::error_code();
+  }
+  else if (impl.safe_cancellation_thread_id_ == ::GetCurrentThreadId())
+  {
+    // Asynchronous operations have been started from the current thread only,
+    // so it is safe to try to cancel them using CancelIo.
+    if (!::CancelIo(impl.handle_))
+    {
+      DWORD last_error = ::GetLastError();
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+    }
+    else
+    {
+      ec = asio::error_code();
+    }
+  }
+  else
+  {
+    // Asynchronous operations have been started from more than one thread,
+    // so cancellation is not safe.
+    ec = asio::error::operation_not_supported;
+  }
+
+  return ec;
+}
+
+size_t win_iocp_handle_service::do_write(
+    win_iocp_handle_service::implementation_type& impl, uint64_t offset,
+    const asio::const_buffer& buffer, asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  // A request to write 0 bytes on a handle is a no-op.
+  if (buffer.size() == 0)
+  {
+    ec = asio::error_code();
+    return 0;
+  }
+
+  overlapped_wrapper overlapped(ec);
+  if (ec)
+  {
+    return 0;
+  }
+
+  // Write the data. 
+  overlapped.Offset = offset & 0xFFFFFFFF;
+  overlapped.OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
+  BOOL ok = ::WriteFile(impl.handle_, buffer.data(),
+      static_cast<DWORD>(buffer.size()), 0, &overlapped);
+  if (!ok) 
+  {
+    DWORD last_error = ::GetLastError();
+    if (last_error != ERROR_IO_PENDING)
+    {
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+      return 0;
+    }
+  }
+
+  // Wait for the operation to complete.
+  DWORD bytes_transferred = 0;
+  ok = ::GetOverlappedResult(impl.handle_,
+      &overlapped, &bytes_transferred, TRUE);
+  if (!ok)
+  {
+    DWORD last_error = ::GetLastError();
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return 0;
+  }
+
+  ec = asio::error_code();
+  return bytes_transferred;
+}
+
+void win_iocp_handle_service::start_write_op(
+    win_iocp_handle_service::implementation_type& impl, uint64_t offset,
+    const asio::const_buffer& buffer, operation* op)
+{
+  update_cancellation_thread_id(impl);
+  iocp_service_.work_started();
+
+  if (!is_open(impl))
+  {
+    iocp_service_.on_completion(op, asio::error::bad_descriptor);
+  }
+  else if (buffer.size() == 0)
+  {
+    // A request to write 0 bytes on a handle is a no-op.
+    iocp_service_.on_completion(op);
+  }
+  else
+  {
+    DWORD bytes_transferred = 0;
+    op->Offset = offset & 0xFFFFFFFF;
+    op->OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
+    BOOL ok = ::WriteFile(impl.handle_, buffer.data(),
+        static_cast<DWORD>(buffer.size()),
+        &bytes_transferred, op);
+    DWORD last_error = ::GetLastError();
+    if (!ok && last_error != ERROR_IO_PENDING
+        && last_error != ERROR_MORE_DATA)
+    {
+      iocp_service_.on_completion(op, last_error, bytes_transferred);
+    }
+    else
+    {
+      iocp_service_.on_pending(op);
+    }
+  }
+}
+
+size_t win_iocp_handle_service::do_read(
+    win_iocp_handle_service::implementation_type& impl, uint64_t offset,
+    const asio::mutable_buffer& buffer, asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+  
+  // A request to read 0 bytes on a stream handle is a no-op.
+  if (buffer.size() == 0)
+  {
+    ec = asio::error_code();
+    return 0;
+  }
+
+  overlapped_wrapper overlapped(ec);
+  if (ec)
+  {
+    return 0;
+  }
+
+  // Read some data.
+  overlapped.Offset = offset & 0xFFFFFFFF;
+  overlapped.OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
+  BOOL ok = ::ReadFile(impl.handle_, buffer.data(),
+      static_cast<DWORD>(buffer.size()), 0, &overlapped);
+  if (!ok) 
+  {
+    DWORD last_error = ::GetLastError();
+    if (last_error != ERROR_IO_PENDING && last_error != ERROR_MORE_DATA)
+    {
+      if (last_error == ERROR_HANDLE_EOF)
+      {
+        ec = asio::error::eof;
+      }
+      else
+      {
+        ec = asio::error_code(last_error,
+            asio::error::get_system_category());
+      }
+      return 0;
+    }
+  }
+
+  // Wait for the operation to complete.
+  DWORD bytes_transferred = 0;
+  ok = ::GetOverlappedResult(impl.handle_,
+      &overlapped, &bytes_transferred, TRUE);
+  if (!ok)
+  {
+    DWORD last_error = ::GetLastError();
+    if (last_error == ERROR_HANDLE_EOF)
+    {
+      ec = asio::error::eof;
+    }
+    else
+    {
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+    }
+    return (last_error == ERROR_MORE_DATA) ? bytes_transferred : 0;
+  }
+
+  ec = asio::error_code();
+  return bytes_transferred;
+}
+
+void win_iocp_handle_service::start_read_op(
+    win_iocp_handle_service::implementation_type& impl, uint64_t offset,
+    const asio::mutable_buffer& buffer, operation* op)
+{
+  update_cancellation_thread_id(impl);
+  iocp_service_.work_started();
+
+  if (!is_open(impl))
+  {
+    iocp_service_.on_completion(op, asio::error::bad_descriptor);
+  }
+  else if (buffer.size() == 0)
+  {
+    // A request to read 0 bytes on a handle is a no-op.
+    iocp_service_.on_completion(op);
+  }
+  else
+  {
+    DWORD bytes_transferred = 0;
+    op->Offset = offset & 0xFFFFFFFF;
+    op->OffsetHigh = (offset >> 32) & 0xFFFFFFFF;
+    BOOL ok = ::ReadFile(impl.handle_, buffer.data(),
+        static_cast<DWORD>(buffer.size()),
+        &bytes_transferred, op);
+    DWORD last_error = ::GetLastError();
+    if (!ok && last_error != ERROR_IO_PENDING
+        && last_error != ERROR_MORE_DATA)
+    {
+      iocp_service_.on_completion(op, last_error, bytes_transferred);
+    }
+    else
+    {
+      iocp_service_.on_pending(op);
+    }
+  }
+}
+
+void win_iocp_handle_service::update_cancellation_thread_id(
+    win_iocp_handle_service::implementation_type& impl)
+{
+  if (impl.safe_cancellation_thread_id_ == 0)
+    impl.safe_cancellation_thread_id_ = ::GetCurrentThreadId();
+  else if (impl.safe_cancellation_thread_id_ != ::GetCurrentThreadId())
+    impl.safe_cancellation_thread_id_ = ~DWORD(0);
+}
+
+void win_iocp_handle_service::close_for_destruction(implementation_type& impl)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((iocp_service_.context(), "handle",
+          &impl, reinterpret_cast<uintmax_t>(impl.handle_), "close"));
+
+    ::CloseHandle(impl.handle_);
+    impl.handle_ = INVALID_HANDLE_VALUE;
+    impl.safe_cancellation_thread_id_ = 0;
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_IMPL_WIN_IOCP_HANDLE_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_iocp_io_context.hpp b/subprojects/asio/include/asio/detail/impl/win_iocp_io_context.hpp
new file mode 100644
index 000000000..44887d7c2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_iocp_io_context.hpp
@@ -0,0 +1,103 @@
+//
+// detail/impl/win_iocp_io_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_HPP
+#define ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/completion_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+void win_iocp_io_context::add_timer_queue(
+    timer_queue<Time_Traits>& queue)
+{
+  do_add_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void win_iocp_io_context::remove_timer_queue(
+    timer_queue<Time_Traits>& queue)
+{
+  do_remove_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void win_iocp_io_context::schedule_timer(timer_queue<Time_Traits>& queue,
+    const typename Time_Traits::time_type& time,
+    typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op)
+{
+  // If the service has been shut down we silently discard the timer.
+  if (::InterlockedExchangeAdd(&shutdown_, 0) != 0)
+  {
+    post_immediate_completion(op, false);
+    return;
+  }
+
+  mutex::scoped_lock lock(dispatch_mutex_);
+
+  bool earliest = queue.enqueue_timer(time, timer, op);
+  work_started();
+  if (earliest)
+    update_timeout();
+}
+
+template <typename Time_Traits>
+std::size_t win_iocp_io_context::cancel_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& timer,
+    std::size_t max_cancelled)
+{
+  // If the service has been shut down we silently ignore the cancellation.
+  if (::InterlockedExchangeAdd(&shutdown_, 0) != 0)
+    return 0;
+
+  mutex::scoped_lock lock(dispatch_mutex_);
+  op_queue<win_iocp_operation> ops;
+  std::size_t n = queue.cancel_timer(timer, ops, max_cancelled);
+  post_deferred_completions(ops);
+  return n;
+}
+
+template <typename Time_Traits>
+void win_iocp_io_context::move_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& to,
+    typename timer_queue<Time_Traits>::per_timer_data& from)
+{
+  asio::detail::mutex::scoped_lock lock(dispatch_mutex_);
+  op_queue<operation> ops;
+  queue.cancel_timer(to, ops);
+  queue.move_timer(to, from);
+  lock.unlock();
+  post_deferred_completions(ops);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_iocp_io_context.ipp b/subprojects/asio/include/asio/detail/impl/win_iocp_io_context.ipp
new file mode 100644
index 000000000..c371b86b2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_iocp_io_context.ipp
@@ -0,0 +1,554 @@
+//
+// detail/impl/win_iocp_io_context.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_IPP
+#define ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/error.hpp"
+#include "asio/detail/cstdint.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_iocp_io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct win_iocp_io_context::work_finished_on_block_exit
+{
+  ~work_finished_on_block_exit()
+  {
+    io_context_->work_finished();
+  }
+
+  win_iocp_io_context* io_context_;
+};
+
+struct win_iocp_io_context::timer_thread_function
+{
+  void operator()()
+  {
+    while (::InterlockedExchangeAdd(&io_context_->shutdown_, 0) == 0)
+    {
+      if (::WaitForSingleObject(io_context_->waitable_timer_.handle,
+            INFINITE) == WAIT_OBJECT_0)
+      {
+        ::InterlockedExchange(&io_context_->dispatch_required_, 1);
+        ::PostQueuedCompletionStatus(io_context_->iocp_.handle,
+            0, wake_for_dispatch, 0);
+      }
+    }
+  }
+
+  win_iocp_io_context* io_context_;
+};
+
+win_iocp_io_context::win_iocp_io_context(
+    asio::execution_context& ctx, int concurrency_hint)
+  : execution_context_service_base<win_iocp_io_context>(ctx),
+    iocp_(),
+    outstanding_work_(0),
+    stopped_(0),
+    stop_event_posted_(0),
+    shutdown_(0),
+    gqcs_timeout_(get_gqcs_timeout()),
+    dispatch_required_(0),
+    concurrency_hint_(concurrency_hint)
+{
+  ASIO_HANDLER_TRACKING_INIT;
+
+  iocp_.handle = ::CreateIoCompletionPort(INVALID_HANDLE_VALUE, 0, 0,
+      static_cast<DWORD>(concurrency_hint >= 0 ? concurrency_hint : DWORD(~0)));
+  if (!iocp_.handle)
+  {
+    DWORD last_error = ::GetLastError();
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "iocp");
+  }
+}
+
+void win_iocp_io_context::shutdown()
+{
+  ::InterlockedExchange(&shutdown_, 1);
+
+  if (timer_thread_.get())
+  {
+    LARGE_INTEGER timeout;
+    timeout.QuadPart = 1;
+    ::SetWaitableTimer(waitable_timer_.handle, &timeout, 1, 0, 0, FALSE);
+  }
+
+  while (::InterlockedExchangeAdd(&outstanding_work_, 0) > 0)
+  {
+    op_queue<win_iocp_operation> ops;
+    timer_queues_.get_all_timers(ops);
+    ops.push(completed_ops_);
+    if (!ops.empty())
+    {
+      while (win_iocp_operation* op = ops.front())
+      {
+        ops.pop();
+        ::InterlockedDecrement(&outstanding_work_);
+        op->destroy();
+      }
+    }
+    else
+    {
+      DWORD bytes_transferred = 0;
+      dword_ptr_t completion_key = 0;
+      LPOVERLAPPED overlapped = 0;
+      ::GetQueuedCompletionStatus(iocp_.handle, &bytes_transferred,
+          &completion_key, &overlapped, gqcs_timeout_);
+      if (overlapped)
+      {
+        ::InterlockedDecrement(&outstanding_work_);
+        static_cast<win_iocp_operation*>(overlapped)->destroy();
+      }
+    }
+  }
+
+  if (timer_thread_.get())
+    timer_thread_->join();
+}
+
+asio::error_code win_iocp_io_context::register_handle(
+    HANDLE handle, asio::error_code& ec)
+{
+  if (::CreateIoCompletionPort(handle, iocp_.handle, 0, 0) == 0)
+  {
+    DWORD last_error = ::GetLastError();
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+  }
+  else
+  {
+    ec = asio::error_code();
+  }
+  return ec;
+}
+
+size_t win_iocp_io_context::run(asio::error_code& ec)
+{
+  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
+  {
+    stop();
+    ec = asio::error_code();
+    return 0;
+  }
+
+  win_iocp_thread_info this_thread;
+  thread_call_stack::context ctx(this, this_thread);
+
+  size_t n = 0;
+  while (do_one(INFINITE, ec))
+    if (n != (std::numeric_limits<size_t>::max)())
+      ++n;
+  return n;
+}
+
+size_t win_iocp_io_context::run_one(asio::error_code& ec)
+{
+  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
+  {
+    stop();
+    ec = asio::error_code();
+    return 0;
+  }
+
+  win_iocp_thread_info this_thread;
+  thread_call_stack::context ctx(this, this_thread);
+
+  return do_one(INFINITE, ec);
+}
+
+size_t win_iocp_io_context::wait_one(long usec, asio::error_code& ec)
+{
+  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
+  {
+    stop();
+    ec = asio::error_code();
+    return 0;
+  }
+
+  win_iocp_thread_info this_thread;
+  thread_call_stack::context ctx(this, this_thread);
+
+  return do_one(usec < 0 ? INFINITE : ((usec - 1) / 1000 + 1), ec);
+}
+
+size_t win_iocp_io_context::poll(asio::error_code& ec)
+{
+  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
+  {
+    stop();
+    ec = asio::error_code();
+    return 0;
+  }
+
+  win_iocp_thread_info this_thread;
+  thread_call_stack::context ctx(this, this_thread);
+
+  size_t n = 0;
+  while (do_one(0, ec))
+    if (n != (std::numeric_limits<size_t>::max)())
+      ++n;
+  return n;
+}
+
+size_t win_iocp_io_context::poll_one(asio::error_code& ec)
+{
+  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
+  {
+    stop();
+    ec = asio::error_code();
+    return 0;
+  }
+
+  win_iocp_thread_info this_thread;
+  thread_call_stack::context ctx(this, this_thread);
+
+  return do_one(0, ec);
+}
+
+void win_iocp_io_context::stop()
+{
+  if (::InterlockedExchange(&stopped_, 1) == 0)
+  {
+    if (::InterlockedExchange(&stop_event_posted_, 1) == 0)
+    {
+      if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, 0))
+      {
+        DWORD last_error = ::GetLastError();
+        asio::error_code ec(last_error,
+            asio::error::get_system_category());
+        asio::detail::throw_error(ec, "pqcs");
+      }
+    }
+  }
+}
+
+void win_iocp_io_context::post_deferred_completion(win_iocp_operation* op)
+{
+  // Flag the operation as ready.
+  op->ready_ = 1;
+
+  // Enqueue the operation on the I/O completion port.
+  if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, op))
+  {
+    // Out of resources. Put on completed queue instead.
+    mutex::scoped_lock lock(dispatch_mutex_);
+    completed_ops_.push(op);
+    ::InterlockedExchange(&dispatch_required_, 1);
+  }
+}
+
+void win_iocp_io_context::post_deferred_completions(
+    op_queue<win_iocp_operation>& ops)
+{
+  while (win_iocp_operation* op = ops.front())
+  {
+    ops.pop();
+
+    // Flag the operation as ready.
+    op->ready_ = 1;
+
+    // Enqueue the operation on the I/O completion port.
+    if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, op))
+    {
+      // Out of resources. Put on completed queue instead.
+      mutex::scoped_lock lock(dispatch_mutex_);
+      completed_ops_.push(op);
+      completed_ops_.push(ops);
+      ::InterlockedExchange(&dispatch_required_, 1);
+    }
+  }
+}
+
+void win_iocp_io_context::abandon_operations(
+    op_queue<win_iocp_operation>& ops)
+{
+  while (win_iocp_operation* op = ops.front())
+  {
+    ops.pop();
+    ::InterlockedDecrement(&outstanding_work_);
+    op->destroy();
+  }
+}
+
+void win_iocp_io_context::on_pending(win_iocp_operation* op)
+{
+  if (::InterlockedCompareExchange(&op->ready_, 1, 0) == 1)
+  {
+    // Enqueue the operation on the I/O completion port.
+    if (!::PostQueuedCompletionStatus(iocp_.handle,
+          0, overlapped_contains_result, op))
+    {
+      // Out of resources. Put on completed queue instead.
+      mutex::scoped_lock lock(dispatch_mutex_);
+      completed_ops_.push(op);
+      ::InterlockedExchange(&dispatch_required_, 1);
+    }
+  }
+}
+
+void win_iocp_io_context::on_completion(win_iocp_operation* op,
+    DWORD last_error, DWORD bytes_transferred)
+{
+  // Flag that the operation is ready for invocation.
+  op->ready_ = 1;
+
+  // Store results in the OVERLAPPED structure.
+  op->Internal = reinterpret_cast<ulong_ptr_t>(
+      &asio::error::get_system_category());
+  op->Offset = last_error;
+  op->OffsetHigh = bytes_transferred;
+
+  // Enqueue the operation on the I/O completion port.
+  if (!::PostQueuedCompletionStatus(iocp_.handle,
+        0, overlapped_contains_result, op))
+  {
+    // Out of resources. Put on completed queue instead.
+    mutex::scoped_lock lock(dispatch_mutex_);
+    completed_ops_.push(op);
+    ::InterlockedExchange(&dispatch_required_, 1);
+  }
+}
+
+void win_iocp_io_context::on_completion(win_iocp_operation* op,
+    const asio::error_code& ec, DWORD bytes_transferred)
+{
+  // Flag that the operation is ready for invocation.
+  op->ready_ = 1;
+
+  // Store results in the OVERLAPPED structure.
+  op->Internal = reinterpret_cast<ulong_ptr_t>(&ec.category());
+  op->Offset = ec.value();
+  op->OffsetHigh = bytes_transferred;
+
+  // Enqueue the operation on the I/O completion port.
+  if (!::PostQueuedCompletionStatus(iocp_.handle,
+        0, overlapped_contains_result, op))
+  {
+    // Out of resources. Put on completed queue instead.
+    mutex::scoped_lock lock(dispatch_mutex_);
+    completed_ops_.push(op);
+    ::InterlockedExchange(&dispatch_required_, 1);
+  }
+}
+
+size_t win_iocp_io_context::do_one(DWORD msec, asio::error_code& ec)
+{
+  for (;;)
+  {
+    // Try to acquire responsibility for dispatching timers and completed ops.
+    if (::InterlockedCompareExchange(&dispatch_required_, 0, 1) == 1)
+    {
+      mutex::scoped_lock lock(dispatch_mutex_);
+
+      // Dispatch pending timers and operations.
+      op_queue<win_iocp_operation> ops;
+      ops.push(completed_ops_);
+      timer_queues_.get_ready_timers(ops);
+      post_deferred_completions(ops);
+      update_timeout();
+    }
+
+    // Get the next operation from the queue.
+    DWORD bytes_transferred = 0;
+    dword_ptr_t completion_key = 0;
+    LPOVERLAPPED overlapped = 0;
+    ::SetLastError(0);
+    BOOL ok = ::GetQueuedCompletionStatus(iocp_.handle,
+        &bytes_transferred, &completion_key, &overlapped,
+        msec < gqcs_timeout_ ? msec : gqcs_timeout_);
+    DWORD last_error = ::GetLastError();
+
+    if (overlapped)
+    {
+      win_iocp_operation* op = static_cast<win_iocp_operation*>(overlapped);
+      asio::error_code result_ec(last_error,
+          asio::error::get_system_category());
+
+      // We may have been passed the last_error and bytes_transferred in the
+      // OVERLAPPED structure itself.
+      if (completion_key == overlapped_contains_result)
+      {
+        result_ec = asio::error_code(static_cast<int>(op->Offset),
+            *reinterpret_cast<asio::error_category*>(op->Internal));
+        bytes_transferred = op->OffsetHigh;
+      }
+
+      // Otherwise ensure any result has been saved into the OVERLAPPED
+      // structure.
+      else
+      {
+        op->Internal = reinterpret_cast<ulong_ptr_t>(&result_ec.category());
+        op->Offset = result_ec.value();
+        op->OffsetHigh = bytes_transferred;
+      }
+
+      // Dispatch the operation only if ready. The operation may not be ready
+      // if the initiating function (e.g. a call to WSARecv) has not yet
+      // returned. This is because the initiating function still wants access
+      // to the operation's OVERLAPPED structure.
+      if (::InterlockedCompareExchange(&op->ready_, 1, 0) == 1)
+      {
+        // Ensure the count of outstanding work is decremented on block exit.
+        work_finished_on_block_exit on_exit = { this };
+        (void)on_exit;
+
+        op->complete(this, result_ec, bytes_transferred);
+        ec = asio::error_code();
+        return 1;
+      }
+    }
+    else if (!ok)
+    {
+      if (last_error != WAIT_TIMEOUT)
+      {
+        ec = asio::error_code(last_error,
+            asio::error::get_system_category());
+        return 0;
+      }
+
+      // If we're waiting indefinitely we need to keep going until we get a
+      // real handler.
+      if (msec == INFINITE)
+        continue;
+
+      ec = asio::error_code();
+      return 0;
+    }
+    else if (completion_key == wake_for_dispatch)
+    {
+      // We have been woken up to try to acquire responsibility for dispatching
+      // timers and completed operations.
+    }
+    else
+    {
+      // Indicate that there is no longer an in-flight stop event.
+      ::InterlockedExchange(&stop_event_posted_, 0);
+
+      // The stopped_ flag is always checked to ensure that any leftover
+      // stop events from a previous run invocation are ignored.
+      if (::InterlockedExchangeAdd(&stopped_, 0) != 0)
+      {
+        // Wake up next thread that is blocked on GetQueuedCompletionStatus.
+        if (::InterlockedExchange(&stop_event_posted_, 1) == 0)
+        {
+          if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, 0))
+          {
+            last_error = ::GetLastError();
+            ec = asio::error_code(last_error,
+                asio::error::get_system_category());
+            return 0;
+          }
+        }
+
+        ec = asio::error_code();
+        return 0;
+      }
+    }
+  }
+}
+
+DWORD win_iocp_io_context::get_gqcs_timeout()
+{
+  OSVERSIONINFOEX osvi;
+  ZeroMemory(&osvi, sizeof(osvi));
+  osvi.dwOSVersionInfoSize = sizeof(osvi);
+  osvi.dwMajorVersion = 6ul;
+
+  const uint64_t condition_mask = ::VerSetConditionMask(
+      0, VER_MAJORVERSION, VER_GREATER_EQUAL);
+
+  if (!!::VerifyVersionInfo(&osvi, VER_MAJORVERSION, condition_mask))
+    return INFINITE;
+
+  return default_gqcs_timeout;
+}
+
+void win_iocp_io_context::do_add_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(dispatch_mutex_);
+
+  timer_queues_.insert(&queue);
+
+  if (!waitable_timer_.handle)
+  {
+    waitable_timer_.handle = ::CreateWaitableTimer(0, FALSE, 0);
+    if (waitable_timer_.handle == 0)
+    {
+      DWORD last_error = ::GetLastError();
+      asio::error_code ec(last_error,
+          asio::error::get_system_category());
+      asio::detail::throw_error(ec, "timer");
+    }
+
+    LARGE_INTEGER timeout;
+    timeout.QuadPart = -max_timeout_usec;
+    timeout.QuadPart *= 10;
+    ::SetWaitableTimer(waitable_timer_.handle,
+        &timeout, max_timeout_msec, 0, 0, FALSE);
+  }
+
+  if (!timer_thread_.get())
+  {
+    timer_thread_function thread_function = { this };
+    timer_thread_.reset(new thread(thread_function, 65536));
+  }
+}
+
+void win_iocp_io_context::do_remove_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(dispatch_mutex_);
+
+  timer_queues_.erase(&queue);
+}
+
+void win_iocp_io_context::update_timeout()
+{
+  if (timer_thread_.get())
+  {
+    // There's no point updating the waitable timer if the new timeout period
+    // exceeds the maximum timeout. In that case, we might as well wait for the
+    // existing period of the timer to expire.
+    long timeout_usec = timer_queues_.wait_duration_usec(max_timeout_usec);
+    if (timeout_usec < max_timeout_usec)
+    {
+      LARGE_INTEGER timeout;
+      timeout.QuadPart = -timeout_usec;
+      timeout.QuadPart *= 10;
+      ::SetWaitableTimer(waitable_timer_.handle,
+          &timeout, max_timeout_msec, 0, 0, FALSE);
+    }
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_iocp_serial_port_service.ipp b/subprojects/asio/include/asio/detail/impl/win_iocp_serial_port_service.ipp
new file mode 100644
index 000000000..4a9b8cd9f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_iocp_serial_port_service.ipp
@@ -0,0 +1,181 @@
+//
+// detail/impl/win_iocp_serial_port_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_IOCP_SERIAL_PORT_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_WIN_IOCP_SERIAL_PORT_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP) && defined(ASIO_HAS_SERIAL_PORT)
+
+#include <cstring>
+#include "asio/detail/win_iocp_serial_port_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+win_iocp_serial_port_service::win_iocp_serial_port_service(
+    asio::io_context& io_context)
+  : service_base<win_iocp_serial_port_service>(io_context),
+    handle_service_(io_context)
+{
+}
+
+void win_iocp_serial_port_service::shutdown()
+{
+}
+
+asio::error_code win_iocp_serial_port_service::open(
+    win_iocp_serial_port_service::implementation_type& impl,
+    const std::string& device, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  // For convenience, add a leading \\.\ sequence if not already present.
+  std::string name = (device[0] == '\\') ? device : "\\\\.\\" + device;
+
+  // Open a handle to the serial port.
+  ::HANDLE handle = ::CreateFileA(name.c_str(),
+      GENERIC_READ | GENERIC_WRITE, 0, 0,
+      OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0);
+  if (handle == INVALID_HANDLE_VALUE)
+  {
+    DWORD last_error = ::GetLastError();
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  // Determine the initial serial port parameters.
+  using namespace std; // For memset.
+  ::DCB dcb;
+  memset(&dcb, 0, sizeof(DCB));
+  dcb.DCBlength = sizeof(DCB);
+  if (!::GetCommState(handle, &dcb))
+  {
+    DWORD last_error = ::GetLastError();
+    ::CloseHandle(handle);
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  // Set some default serial port parameters. This implementation does not
+  // support changing these, so they might as well be in a known state.
+  dcb.fBinary = TRUE; // Win32 only supports binary mode.
+  dcb.fDsrSensitivity = FALSE;
+  dcb.fNull = FALSE; // Do not ignore NULL characters.
+  dcb.fAbortOnError = FALSE; // Ignore serial framing errors.
+  if (!::SetCommState(handle, &dcb))
+  {
+    DWORD last_error = ::GetLastError();
+    ::CloseHandle(handle);
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  // Set up timeouts so that the serial port will behave similarly to a
+  // network socket. Reads wait for at least one byte, then return with
+  // whatever they have. Writes return once everything is out the door.
+  ::COMMTIMEOUTS timeouts;
+  timeouts.ReadIntervalTimeout = 1;
+  timeouts.ReadTotalTimeoutMultiplier = 0;
+  timeouts.ReadTotalTimeoutConstant = 0;
+  timeouts.WriteTotalTimeoutMultiplier = 0;
+  timeouts.WriteTotalTimeoutConstant = 0;
+  if (!::SetCommTimeouts(handle, &timeouts))
+  {
+    DWORD last_error = ::GetLastError();
+    ::CloseHandle(handle);
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  // We're done. Take ownership of the serial port handle.
+  if (handle_service_.assign(impl, handle, ec))
+    ::CloseHandle(handle);
+  return ec;
+}
+
+asio::error_code win_iocp_serial_port_service::do_set_option(
+    win_iocp_serial_port_service::implementation_type& impl,
+    win_iocp_serial_port_service::store_function_type store,
+    const void* option, asio::error_code& ec)
+{
+  using namespace std; // For memcpy.
+
+  ::DCB dcb;
+  memset(&dcb, 0, sizeof(DCB));
+  dcb.DCBlength = sizeof(DCB);
+  if (!::GetCommState(handle_service_.native_handle(impl), &dcb))
+  {
+    DWORD last_error = ::GetLastError();
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  if (store(option, dcb, ec))
+    return ec;
+
+  if (!::SetCommState(handle_service_.native_handle(impl), &dcb))
+  {
+    DWORD last_error = ::GetLastError();
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code win_iocp_serial_port_service::do_get_option(
+    const win_iocp_serial_port_service::implementation_type& impl,
+    win_iocp_serial_port_service::load_function_type load,
+    void* option, asio::error_code& ec) const
+{
+  using namespace std; // For memset.
+
+  ::DCB dcb;
+  memset(&dcb, 0, sizeof(DCB));
+  dcb.DCBlength = sizeof(DCB);
+  if (!::GetCommState(handle_service_.native_handle(impl), &dcb))
+  {
+    DWORD last_error = ::GetLastError();
+    ec = asio::error_code(last_error,
+        asio::error::get_system_category());
+    return ec;
+  }
+
+  return load(option, dcb, ec);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP) && defined(ASIO_HAS_SERIAL_PORT)
+
+#endif // ASIO_DETAIL_IMPL_WIN_IOCP_SERIAL_PORT_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_iocp_socket_service_base.ipp b/subprojects/asio/include/asio/detail/impl/win_iocp_socket_service_base.ipp
new file mode 100644
index 000000000..6c478cd2f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_iocp_socket_service_base.ipp
@@ -0,0 +1,799 @@
+//
+// detail/impl/win_iocp_socket_service_base.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP
+#define ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/win_iocp_socket_service_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+win_iocp_socket_service_base::win_iocp_socket_service_base(
+    asio::io_context& io_context)
+  : io_context_(io_context),
+    iocp_service_(use_service<win_iocp_io_context>(io_context)),
+    reactor_(0),
+    connect_ex_(0),
+    nt_set_info_(0),
+    mutex_(),
+    impl_list_(0)
+{
+}
+
+void win_iocp_socket_service_base::base_shutdown()
+{
+  // Close all implementations, causing all operations to complete.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  base_implementation_type* impl = impl_list_;
+  while (impl)
+  {
+    close_for_destruction(*impl);
+    impl = impl->next_;
+  }
+}
+
+void win_iocp_socket_service_base::construct(
+    win_iocp_socket_service_base::base_implementation_type& impl)
+{
+  impl.socket_ = invalid_socket;
+  impl.state_ = 0;
+  impl.cancel_token_.reset();
+#if defined(ASIO_ENABLE_CANCELIO)
+  impl.safe_cancellation_thread_id_ = 0;
+#endif // defined(ASIO_ENABLE_CANCELIO)
+
+  // Insert implementation into linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  impl.next_ = impl_list_;
+  impl.prev_ = 0;
+  if (impl_list_)
+    impl_list_->prev_ = &impl;
+  impl_list_ = &impl;
+}
+
+void win_iocp_socket_service_base::base_move_construct(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    win_iocp_socket_service_base::base_implementation_type& other_impl)
+{
+  impl.socket_ = other_impl.socket_;
+  other_impl.socket_ = invalid_socket;
+
+  impl.state_ = other_impl.state_;
+  other_impl.state_ = 0;
+
+  impl.cancel_token_ = other_impl.cancel_token_;
+  other_impl.cancel_token_.reset();
+
+#if defined(ASIO_ENABLE_CANCELIO)
+  impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_;
+  other_impl.safe_cancellation_thread_id_ = 0;
+#endif // defined(ASIO_ENABLE_CANCELIO)
+
+  // Insert implementation into linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  impl.next_ = impl_list_;
+  impl.prev_ = 0;
+  if (impl_list_)
+    impl_list_->prev_ = &impl;
+  impl_list_ = &impl;
+}
+
+void win_iocp_socket_service_base::base_move_assign(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    win_iocp_socket_service_base& other_service,
+    win_iocp_socket_service_base::base_implementation_type& other_impl)
+{
+  close_for_destruction(impl);
+
+  if (this != &other_service)
+  {
+    // Remove implementation from linked list of all implementations.
+    asio::detail::mutex::scoped_lock lock(mutex_);
+    if (impl_list_ == &impl)
+      impl_list_ = impl.next_;
+    if (impl.prev_)
+      impl.prev_->next_ = impl.next_;
+    if (impl.next_)
+      impl.next_->prev_= impl.prev_;
+    impl.next_ = 0;
+    impl.prev_ = 0;
+  }
+
+  impl.socket_ = other_impl.socket_;
+  other_impl.socket_ = invalid_socket;
+
+  impl.state_ = other_impl.state_;
+  other_impl.state_ = 0;
+
+  impl.cancel_token_ = other_impl.cancel_token_;
+  other_impl.cancel_token_.reset();
+
+#if defined(ASIO_ENABLE_CANCELIO)
+  impl.safe_cancellation_thread_id_ = other_impl.safe_cancellation_thread_id_;
+  other_impl.safe_cancellation_thread_id_ = 0;
+#endif // defined(ASIO_ENABLE_CANCELIO)
+
+  if (this != &other_service)
+  {
+    // Insert implementation into linked list of all implementations.
+    asio::detail::mutex::scoped_lock lock(other_service.mutex_);
+    impl.next_ = other_service.impl_list_;
+    impl.prev_ = 0;
+    if (other_service.impl_list_)
+      other_service.impl_list_->prev_ = &impl;
+    other_service.impl_list_ = &impl;
+  }
+}
+
+void win_iocp_socket_service_base::destroy(
+    win_iocp_socket_service_base::base_implementation_type& impl)
+{
+  close_for_destruction(impl);
+
+  // Remove implementation from linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  if (impl_list_ == &impl)
+    impl_list_ = impl.next_;
+  if (impl.prev_)
+    impl.prev_->next_ = impl.next_;
+  if (impl.next_)
+    impl.next_->prev_= impl.prev_;
+  impl.next_ = 0;
+  impl.prev_ = 0;
+}
+
+asio::error_code win_iocp_socket_service_base::close(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((iocp_service_.context(),
+          "socket", &impl, impl.socket_, "close"));
+
+    // Check if the reactor was created, in which case we need to close the
+    // socket on the reactor as well to cancel any operations that might be
+    // running there.
+    select_reactor* r = static_cast<select_reactor*>(
+          interlocked_compare_exchange_pointer(
+            reinterpret_cast<void**>(&reactor_), 0, 0));
+    if (r)
+      r->deregister_descriptor(impl.socket_, impl.reactor_data_, true);
+
+    socket_ops::close(impl.socket_, impl.state_, false, ec);
+
+    if (r)
+      r->cleanup_descriptor_data(impl.reactor_data_);
+  }
+  else
+  {
+    ec = asio::error_code();
+  }
+
+  impl.socket_ = invalid_socket;
+  impl.state_ = 0;
+  impl.cancel_token_.reset();
+#if defined(ASIO_ENABLE_CANCELIO)
+  impl.safe_cancellation_thread_id_ = 0;
+#endif // defined(ASIO_ENABLE_CANCELIO)
+
+  return ec;
+}
+
+socket_type win_iocp_socket_service_base::release(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (!is_open(impl))
+    return invalid_socket;
+
+  cancel(impl, ec);
+  if (ec)
+    return invalid_socket;
+
+  nt_set_info_fn fn = get_nt_set_info();
+  if (fn == 0)
+  {
+    ec = asio::error::operation_not_supported;
+    return invalid_socket;
+  }
+
+  HANDLE sock_as_handle = reinterpret_cast<HANDLE>(impl.socket_);
+  ULONG_PTR iosb[2] = { 0, 0 };
+  void* info[2] = { 0, 0 };
+  if (fn(sock_as_handle, iosb, &info, sizeof(info),
+        61 /* FileReplaceCompletionInformation */))
+  {
+    ec = asio::error::operation_not_supported;
+    return invalid_socket;
+  }
+
+  socket_type tmp = impl.socket_;
+  impl.socket_ = invalid_socket;
+  return tmp;
+}
+
+asio::error_code win_iocp_socket_service_base::cancel(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return ec;
+  }
+
+  ASIO_HANDLER_OPERATION((iocp_service_.context(),
+        "socket", &impl, impl.socket_, "cancel"));
+
+  if (FARPROC cancel_io_ex_ptr = ::GetProcAddress(
+        ::GetModuleHandleA("KERNEL32"), "CancelIoEx"))
+  {
+    // The version of Windows supports cancellation from any thread.
+    typedef BOOL (WINAPI* cancel_io_ex_t)(HANDLE, LPOVERLAPPED);
+    cancel_io_ex_t cancel_io_ex = (cancel_io_ex_t)cancel_io_ex_ptr;
+    socket_type sock = impl.socket_;
+    HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock);
+    if (!cancel_io_ex(sock_as_handle, 0))
+    {
+      DWORD last_error = ::GetLastError();
+      if (last_error == ERROR_NOT_FOUND)
+      {
+        // ERROR_NOT_FOUND means that there were no operations to be
+        // cancelled. We swallow this error to match the behaviour on other
+        // platforms.
+        ec = asio::error_code();
+      }
+      else
+      {
+        ec = asio::error_code(last_error,
+            asio::error::get_system_category());
+      }
+    }
+    else
+    {
+      ec = asio::error_code();
+    }
+  }
+#if defined(ASIO_ENABLE_CANCELIO)
+  else if (impl.safe_cancellation_thread_id_ == 0)
+  {
+    // No operations have been started, so there's nothing to cancel.
+    ec = asio::error_code();
+  }
+  else if (impl.safe_cancellation_thread_id_ == ::GetCurrentThreadId())
+  {
+    // Asynchronous operations have been started from the current thread only,
+    // so it is safe to try to cancel them using CancelIo.
+    socket_type sock = impl.socket_;
+    HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock);
+    if (!::CancelIo(sock_as_handle))
+    {
+      DWORD last_error = ::GetLastError();
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+    }
+    else
+    {
+      ec = asio::error_code();
+    }
+  }
+  else
+  {
+    // Asynchronous operations have been started from more than one thread,
+    // so cancellation is not safe.
+    ec = asio::error::operation_not_supported;
+  }
+#else // defined(ASIO_ENABLE_CANCELIO)
+  else
+  {
+    // Cancellation is not supported as CancelIo may not be used.
+    ec = asio::error::operation_not_supported;
+  }
+#endif // defined(ASIO_ENABLE_CANCELIO)
+
+  // Cancel any operations started via the reactor.
+  if (!ec)
+  {
+    select_reactor* r = static_cast<select_reactor*>(
+          interlocked_compare_exchange_pointer(
+            reinterpret_cast<void**>(&reactor_), 0, 0));
+    if (r)
+      r->cancel_ops(impl.socket_, impl.reactor_data_);
+  }
+
+  return ec;
+}
+
+asio::error_code win_iocp_socket_service_base::do_open(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    int family, int type, int protocol, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  socket_holder sock(socket_ops::socket(family, type, protocol, ec));
+  if (sock.get() == invalid_socket)
+    return ec;
+
+  HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock.get());
+  if (iocp_service_.register_handle(sock_as_handle, ec))
+    return ec;
+
+  impl.socket_ = sock.release();
+  switch (type)
+  {
+  case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break;
+  case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break;
+  default: impl.state_ = 0; break;
+  }
+  impl.cancel_token_.reset(static_cast<void*>(0), socket_ops::noop_deleter());
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code win_iocp_socket_service_base::do_assign(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    int type, socket_type native_socket, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  HANDLE sock_as_handle = reinterpret_cast<HANDLE>(native_socket);
+  if (iocp_service_.register_handle(sock_as_handle, ec))
+    return ec;
+
+  impl.socket_ = native_socket;
+  switch (type)
+  {
+  case SOCK_STREAM: impl.state_ = socket_ops::stream_oriented; break;
+  case SOCK_DGRAM: impl.state_ = socket_ops::datagram_oriented; break;
+  default: impl.state_ = 0; break;
+  }
+  impl.cancel_token_.reset(static_cast<void*>(0), socket_ops::noop_deleter());
+  ec = asio::error_code();
+  return ec;
+}
+
+void win_iocp_socket_service_base::start_send_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    WSABUF* buffers, std::size_t buffer_count,
+    socket_base::message_flags flags, bool noop, operation* op)
+{
+  update_cancellation_thread_id(impl);
+  iocp_service_.work_started();
+
+  if (noop)
+    iocp_service_.on_completion(op);
+  else if (!is_open(impl))
+    iocp_service_.on_completion(op, asio::error::bad_descriptor);
+  else
+  {
+    DWORD bytes_transferred = 0;
+    int result = ::WSASend(impl.socket_, buffers,
+        static_cast<DWORD>(buffer_count), &bytes_transferred, flags, op, 0);
+    DWORD last_error = ::WSAGetLastError();
+    if (last_error == ERROR_PORT_UNREACHABLE)
+      last_error = WSAECONNREFUSED;
+    if (result != 0 && last_error != WSA_IO_PENDING)
+      iocp_service_.on_completion(op, last_error, bytes_transferred);
+    else
+      iocp_service_.on_pending(op);
+  }
+}
+
+void win_iocp_socket_service_base::start_send_to_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    WSABUF* buffers, std::size_t buffer_count,
+    const socket_addr_type* addr, int addrlen,
+    socket_base::message_flags flags, operation* op)
+{
+  update_cancellation_thread_id(impl);
+  iocp_service_.work_started();
+
+  if (!is_open(impl))
+    iocp_service_.on_completion(op, asio::error::bad_descriptor);
+  else
+  {
+    DWORD bytes_transferred = 0;
+    int result = ::WSASendTo(impl.socket_, buffers,
+        static_cast<DWORD>(buffer_count),
+        &bytes_transferred, flags, addr, addrlen, op, 0);
+    DWORD last_error = ::WSAGetLastError();
+    if (last_error == ERROR_PORT_UNREACHABLE)
+      last_error = WSAECONNREFUSED;
+    if (result != 0 && last_error != WSA_IO_PENDING)
+      iocp_service_.on_completion(op, last_error, bytes_transferred);
+    else
+      iocp_service_.on_pending(op);
+  }
+}
+
+void win_iocp_socket_service_base::start_receive_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    WSABUF* buffers, std::size_t buffer_count,
+    socket_base::message_flags flags, bool noop, operation* op)
+{
+  update_cancellation_thread_id(impl);
+  iocp_service_.work_started();
+
+  if (noop)
+    iocp_service_.on_completion(op);
+  else if (!is_open(impl))
+    iocp_service_.on_completion(op, asio::error::bad_descriptor);
+  else
+  {
+    DWORD bytes_transferred = 0;
+    DWORD recv_flags = flags;
+    int result = ::WSARecv(impl.socket_, buffers,
+        static_cast<DWORD>(buffer_count),
+        &bytes_transferred, &recv_flags, op, 0);
+    DWORD last_error = ::WSAGetLastError();
+    if (last_error == ERROR_NETNAME_DELETED)
+      last_error = WSAECONNRESET;
+    else if (last_error == ERROR_PORT_UNREACHABLE)
+      last_error = WSAECONNREFUSED;
+    if (result != 0 && last_error != WSA_IO_PENDING)
+      iocp_service_.on_completion(op, last_error, bytes_transferred);
+    else
+      iocp_service_.on_pending(op);
+  }
+}
+
+void win_iocp_socket_service_base::start_null_buffers_receive_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    socket_base::message_flags flags, reactor_op* op)
+{
+  if ((impl.state_ & socket_ops::stream_oriented) != 0)
+  {
+    // For stream sockets on Windows, we may issue a 0-byte overlapped
+    // WSARecv to wait until there is data available on the socket.
+    ::WSABUF buf = { 0, 0 };
+    start_receive_op(impl, &buf, 1, flags, false, op);
+  }
+  else
+  {
+    start_reactor_op(impl,
+        (flags & socket_base::message_out_of_band)
+          ? select_reactor::except_op : select_reactor::read_op,
+        op);
+  }
+}
+
+void win_iocp_socket_service_base::start_receive_from_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    WSABUF* buffers, std::size_t buffer_count, socket_addr_type* addr,
+    socket_base::message_flags flags, int* addrlen, operation* op)
+{
+  update_cancellation_thread_id(impl);
+  iocp_service_.work_started();
+
+  if (!is_open(impl))
+    iocp_service_.on_completion(op, asio::error::bad_descriptor);
+  else
+  {
+    DWORD bytes_transferred = 0;
+    DWORD recv_flags = flags;
+    int result = ::WSARecvFrom(impl.socket_, buffers,
+        static_cast<DWORD>(buffer_count),
+        &bytes_transferred, &recv_flags, addr, addrlen, op, 0);
+    DWORD last_error = ::WSAGetLastError();
+    if (last_error == ERROR_PORT_UNREACHABLE)
+      last_error = WSAECONNREFUSED;
+    if (result != 0 && last_error != WSA_IO_PENDING)
+      iocp_service_.on_completion(op, last_error, bytes_transferred);
+    else
+      iocp_service_.on_pending(op);
+  }
+}
+
+void win_iocp_socket_service_base::start_accept_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    bool peer_is_open, socket_holder& new_socket, int family, int type,
+    int protocol, void* output_buffer, DWORD address_length, operation* op)
+{
+  update_cancellation_thread_id(impl);
+  iocp_service_.work_started();
+
+  if (!is_open(impl))
+    iocp_service_.on_completion(op, asio::error::bad_descriptor);
+  else if (peer_is_open)
+    iocp_service_.on_completion(op, asio::error::already_open);
+  else
+  {
+    asio::error_code ec;
+    new_socket.reset(socket_ops::socket(family, type, protocol, ec));
+    if (new_socket.get() == invalid_socket)
+      iocp_service_.on_completion(op, ec);
+    else
+    {
+      DWORD bytes_read = 0;
+      BOOL result = ::AcceptEx(impl.socket_, new_socket.get(), output_buffer,
+          0, address_length, address_length, &bytes_read, op);
+      DWORD last_error = ::WSAGetLastError();
+      if (!result && last_error != WSA_IO_PENDING)
+        iocp_service_.on_completion(op, last_error);
+      else
+        iocp_service_.on_pending(op);
+    }
+  }
+}
+
+void win_iocp_socket_service_base::restart_accept_op(
+    socket_type s, socket_holder& new_socket, int family, int type,
+    int protocol, void* output_buffer, DWORD address_length, operation* op)
+{
+  new_socket.reset();
+  iocp_service_.work_started();
+
+  asio::error_code ec;
+  new_socket.reset(socket_ops::socket(family, type, protocol, ec));
+  if (new_socket.get() == invalid_socket)
+    iocp_service_.on_completion(op, ec);
+  else
+  {
+    DWORD bytes_read = 0;
+    BOOL result = ::AcceptEx(s, new_socket.get(), output_buffer,
+        0, address_length, address_length, &bytes_read, op);
+    DWORD last_error = ::WSAGetLastError();
+    if (!result && last_error != WSA_IO_PENDING)
+      iocp_service_.on_completion(op, last_error);
+    else
+      iocp_service_.on_pending(op);
+  }
+}
+
+void win_iocp_socket_service_base::start_reactor_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    int op_type, reactor_op* op)
+{
+  select_reactor& r = get_reactor();
+  update_cancellation_thread_id(impl);
+
+  if (is_open(impl))
+  {
+    r.start_op(op_type, impl.socket_, impl.reactor_data_, op, false, false);
+    return;
+  }
+  else
+    op->ec_ = asio::error::bad_descriptor;
+
+  iocp_service_.post_immediate_completion(op, false);
+}
+
+void win_iocp_socket_service_base::start_connect_op(
+    win_iocp_socket_service_base::base_implementation_type& impl,
+    int family, int type, const socket_addr_type* addr,
+    std::size_t addrlen, win_iocp_socket_connect_op_base* op)
+{
+  // If ConnectEx is available, use that.
+  if (family == ASIO_OS_DEF(AF_INET)
+      || family == ASIO_OS_DEF(AF_INET6))
+  {
+    if (connect_ex_fn connect_ex = get_connect_ex(impl, type))
+    {
+      union address_union
+      {
+        socket_addr_type base;
+        sockaddr_in4_type v4;
+        sockaddr_in6_type v6;
+      } a;
+
+      using namespace std; // For memset.
+      memset(&a, 0, sizeof(a));
+      a.base.sa_family = family;
+
+      socket_ops::bind(impl.socket_, &a.base,
+          family == ASIO_OS_DEF(AF_INET)
+          ? sizeof(a.v4) : sizeof(a.v6), op->ec_);
+      if (op->ec_ && op->ec_ != asio::error::invalid_argument)
+      {
+        iocp_service_.post_immediate_completion(op, false);
+        return;
+      }
+
+      op->connect_ex_ = true;
+      update_cancellation_thread_id(impl);
+      iocp_service_.work_started();
+
+      BOOL result = connect_ex(impl.socket_,
+          addr, static_cast<int>(addrlen), 0, 0, 0, op);
+      DWORD last_error = ::WSAGetLastError();
+      if (!result && last_error != WSA_IO_PENDING)
+        iocp_service_.on_completion(op, last_error);
+      else
+        iocp_service_.on_pending(op);
+      return;
+    }
+  }
+
+  // Otherwise, fall back to a reactor-based implementation.
+  select_reactor& r = get_reactor();
+  update_cancellation_thread_id(impl);
+
+  if ((impl.state_ & socket_ops::non_blocking) != 0
+      || socket_ops::set_internal_non_blocking(
+        impl.socket_, impl.state_, true, op->ec_))
+  {
+    if (socket_ops::connect(impl.socket_, addr, addrlen, op->ec_) != 0)
+    {
+      if (op->ec_ == asio::error::in_progress
+          || op->ec_ == asio::error::would_block)
+      {
+        op->ec_ = asio::error_code();
+        r.start_op(select_reactor::connect_op, impl.socket_,
+            impl.reactor_data_, op, false, false);
+        return;
+      }
+    }
+  }
+
+  r.post_immediate_completion(op, false);
+}
+
+void win_iocp_socket_service_base::close_for_destruction(
+    win_iocp_socket_service_base::base_implementation_type& impl)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((iocp_service_.context(),
+          "socket", &impl, impl.socket_, "close"));
+
+    // Check if the reactor was created, in which case we need to close the
+    // socket on the reactor as well to cancel any operations that might be
+    // running there.
+    select_reactor* r = static_cast<select_reactor*>(
+          interlocked_compare_exchange_pointer(
+            reinterpret_cast<void**>(&reactor_), 0, 0));
+    if (r)
+      r->deregister_descriptor(impl.socket_, impl.reactor_data_, true);
+
+    asio::error_code ignored_ec;
+    socket_ops::close(impl.socket_, impl.state_, true, ignored_ec);
+
+    if (r)
+      r->cleanup_descriptor_data(impl.reactor_data_);
+  }
+
+  impl.socket_ = invalid_socket;
+  impl.state_ = 0;
+  impl.cancel_token_.reset();
+#if defined(ASIO_ENABLE_CANCELIO)
+  impl.safe_cancellation_thread_id_ = 0;
+#endif // defined(ASIO_ENABLE_CANCELIO)
+}
+
+void win_iocp_socket_service_base::update_cancellation_thread_id(
+    win_iocp_socket_service_base::base_implementation_type& impl)
+{
+#if defined(ASIO_ENABLE_CANCELIO)
+  if (impl.safe_cancellation_thread_id_ == 0)
+    impl.safe_cancellation_thread_id_ = ::GetCurrentThreadId();
+  else if (impl.safe_cancellation_thread_id_ != ::GetCurrentThreadId())
+    impl.safe_cancellation_thread_id_ = ~DWORD(0);
+#else // defined(ASIO_ENABLE_CANCELIO)
+  (void)impl;
+#endif // defined(ASIO_ENABLE_CANCELIO)
+}
+
+select_reactor& win_iocp_socket_service_base::get_reactor()
+{
+  select_reactor* r = static_cast<select_reactor*>(
+        interlocked_compare_exchange_pointer(
+          reinterpret_cast<void**>(&reactor_), 0, 0));
+  if (!r)
+  {
+    r = &(use_service<select_reactor>(io_context_));
+    interlocked_exchange_pointer(reinterpret_cast<void**>(&reactor_), r);
+  }
+  return *r;
+}
+
+win_iocp_socket_service_base::connect_ex_fn
+win_iocp_socket_service_base::get_connect_ex(
+    win_iocp_socket_service_base::base_implementation_type& impl, int type)
+{
+#if defined(ASIO_DISABLE_CONNECTEX)
+  (void)impl;
+  (void)type;
+  return 0;
+#else // defined(ASIO_DISABLE_CONNECTEX)
+  if (type != ASIO_OS_DEF(SOCK_STREAM)
+      && type != ASIO_OS_DEF(SOCK_SEQPACKET))
+    return 0;
+
+  void* ptr = interlocked_compare_exchange_pointer(&connect_ex_, 0, 0);
+  if (!ptr)
+  {
+    GUID guid = { 0x25a207b9, 0xddf3, 0x4660,
+      { 0x8e, 0xe9, 0x76, 0xe5, 0x8c, 0x74, 0x06, 0x3e } };
+
+    DWORD bytes = 0;
+    if (::WSAIoctl(impl.socket_, SIO_GET_EXTENSION_FUNCTION_POINTER,
+          &guid, sizeof(guid), &ptr, sizeof(ptr), &bytes, 0, 0) != 0)
+    {
+      // Set connect_ex_ to a special value to indicate that ConnectEx is
+      // unavailable. That way we won't bother trying to look it up again.
+      ptr = this;
+    }
+
+    interlocked_exchange_pointer(&connect_ex_, ptr);
+  }
+
+  return reinterpret_cast<connect_ex_fn>(ptr == this ? 0 : ptr);
+#endif // defined(ASIO_DISABLE_CONNECTEX)
+}
+
+win_iocp_socket_service_base::nt_set_info_fn
+win_iocp_socket_service_base::get_nt_set_info()
+{
+  void* ptr = interlocked_compare_exchange_pointer(&nt_set_info_, 0, 0);
+  if (!ptr)
+  {
+    if (HMODULE h = ::GetModuleHandleA("NTDLL.DLL"))
+      ptr = reinterpret_cast<void*>(GetProcAddress(h, "NtSetInformationFile"));
+
+    // On failure, set nt_set_info_ to a special value to indicate that the
+    // NtSetInformationFile function is unavailable. That way we won't bother
+    // trying to look it up again.
+    interlocked_exchange_pointer(&nt_set_info_, ptr ? ptr : this);
+  }
+
+  return reinterpret_cast<nt_set_info_fn>(ptr == this ? 0 : ptr);
+}
+
+void* win_iocp_socket_service_base::interlocked_compare_exchange_pointer(
+    void** dest, void* exch, void* cmp)
+{
+#if defined(_M_IX86)
+  return reinterpret_cast<void*>(InterlockedCompareExchange(
+        reinterpret_cast<PLONG>(dest), reinterpret_cast<LONG>(exch),
+        reinterpret_cast<LONG>(cmp)));
+#else
+  return InterlockedCompareExchangePointer(dest, exch, cmp);
+#endif
+}
+
+void* win_iocp_socket_service_base::interlocked_exchange_pointer(
+    void** dest, void* val)
+{
+#if defined(_M_IX86)
+  return reinterpret_cast<void*>(InterlockedExchange(
+        reinterpret_cast<PLONG>(dest), reinterpret_cast<LONG>(val)));
+#else
+  return InterlockedExchangePointer(dest, val);
+#endif
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_IMPL_WIN_IOCP_SOCKET_SERVICE_BASE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_mutex.ipp b/subprojects/asio/include/asio/detail/impl/win_mutex.ipp
new file mode 100644
index 000000000..dc58a12cd
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_mutex.ipp
@@ -0,0 +1,84 @@
+//
+// detail/impl/win_mutex.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_MUTEX_IPP
+#define ASIO_DETAIL_IMPL_WIN_MUTEX_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_mutex.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+win_mutex::win_mutex()
+{
+  int error = do_init();
+  asio::error_code ec(error,
+      asio::error::get_system_category());
+  asio::detail::throw_error(ec, "mutex");
+}
+
+int win_mutex::do_init()
+{
+#if defined(__MINGW32__)
+  // Not sure if MinGW supports structured exception handling, so for now
+  // we'll just call the Windows API and hope.
+# if defined(UNDER_CE)
+  ::InitializeCriticalSection(&crit_section_);
+# elif defined(ASIO_WINDOWS_APP)
+  if (!::InitializeCriticalSectionEx(&crit_section_, 0, 0))
+    return ::GetLastError();
+# else
+  if (!::InitializeCriticalSectionAndSpinCount(&crit_section_, 0x80000000))
+    return ::GetLastError();
+# endif
+  return 0;
+#else
+  __try
+  {
+# if defined(UNDER_CE)
+    ::InitializeCriticalSection(&crit_section_);
+# elif defined(ASIO_WINDOWS_APP)
+    if (!::InitializeCriticalSectionEx(&crit_section_, 0, 0))
+      return ::GetLastError();
+# else
+    if (!::InitializeCriticalSectionAndSpinCount(&crit_section_, 0x80000000))
+      return ::GetLastError();
+# endif
+  }
+  __except(GetExceptionCode() == STATUS_NO_MEMORY
+      ? EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH)
+  {
+    return ERROR_OUTOFMEMORY;
+  }
+
+  return 0;
+#endif
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_IMPL_WIN_MUTEX_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_object_handle_service.ipp b/subprojects/asio/include/asio/detail/impl/win_object_handle_service.ipp
new file mode 100644
index 000000000..c5e59d1be
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_object_handle_service.ipp
@@ -0,0 +1,449 @@
+//
+// detail/impl/win_object_handle_service.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2011 Boris Schaeling (boris@highscore.de)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_OBJECT_HANDLE_SERVICE_IPP
+#define ASIO_DETAIL_IMPL_WIN_OBJECT_HANDLE_SERVICE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+
+#include "asio/detail/win_object_handle_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+win_object_handle_service::win_object_handle_service(
+    asio::io_context& io_context)
+  : service_base<win_object_handle_service>(io_context),
+    io_context_(asio::use_service<io_context_impl>(io_context)),
+    mutex_(),
+    impl_list_(0),
+    shutdown_(false)
+{
+}
+
+void win_object_handle_service::shutdown()
+{
+  mutex::scoped_lock lock(mutex_);
+
+  // Setting this flag to true prevents new objects from being registered, and
+  // new asynchronous wait operations from being started. We only need to worry
+  // about cleaning up the operations that are currently in progress.
+  shutdown_ = true;
+
+  op_queue<operation> ops;
+  for (implementation_type* impl = impl_list_; impl; impl = impl->next_)
+    ops.push(impl->op_queue_);
+
+  lock.unlock();
+
+  io_context_.abandon_operations(ops);
+}
+
+void win_object_handle_service::construct(
+    win_object_handle_service::implementation_type& impl)
+{
+  impl.handle_ = INVALID_HANDLE_VALUE;
+  impl.wait_handle_ = INVALID_HANDLE_VALUE;
+  impl.owner_ = this;
+
+  // Insert implementation into linked list of all implementations.
+  mutex::scoped_lock lock(mutex_);
+  if (!shutdown_)
+  {
+    impl.next_ = impl_list_;
+    impl.prev_ = 0;
+    if (impl_list_)
+      impl_list_->prev_ = &impl;
+    impl_list_ = &impl;
+  }
+}
+
+void win_object_handle_service::move_construct(
+    win_object_handle_service::implementation_type& impl,
+    win_object_handle_service::implementation_type& other_impl)
+{
+  mutex::scoped_lock lock(mutex_);
+
+  // Insert implementation into linked list of all implementations.
+  if (!shutdown_)
+  {
+    impl.next_ = impl_list_;
+    impl.prev_ = 0;
+    if (impl_list_)
+      impl_list_->prev_ = &impl;
+    impl_list_ = &impl;
+  }
+
+  impl.handle_ = other_impl.handle_;
+  other_impl.handle_ = INVALID_HANDLE_VALUE;
+  impl.wait_handle_ = other_impl.wait_handle_;
+  other_impl.wait_handle_ = INVALID_HANDLE_VALUE;
+  impl.op_queue_.push(other_impl.op_queue_);
+  impl.owner_ = this;
+
+  // We must not hold the lock while calling UnregisterWaitEx. This is because
+  // the registered callback function might be invoked while we are waiting for
+  // UnregisterWaitEx to complete.
+  lock.unlock();
+
+  if (impl.wait_handle_ != INVALID_HANDLE_VALUE)
+    ::UnregisterWaitEx(impl.wait_handle_, INVALID_HANDLE_VALUE);
+
+  if (!impl.op_queue_.empty())
+    register_wait_callback(impl, lock);
+}
+
+void win_object_handle_service::move_assign(
+    win_object_handle_service::implementation_type& impl,
+    win_object_handle_service& other_service,
+    win_object_handle_service::implementation_type& other_impl)
+{
+  asio::error_code ignored_ec;
+  close(impl, ignored_ec);
+
+  mutex::scoped_lock lock(mutex_);
+
+  if (this != &other_service)
+  {
+    // Remove implementation from linked list of all implementations.
+    if (impl_list_ == &impl)
+      impl_list_ = impl.next_;
+    if (impl.prev_)
+      impl.prev_->next_ = impl.next_;
+    if (impl.next_)
+      impl.next_->prev_= impl.prev_;
+    impl.next_ = 0;
+    impl.prev_ = 0;
+  }
+
+  impl.handle_ = other_impl.handle_;
+  other_impl.handle_ = INVALID_HANDLE_VALUE;
+  impl.wait_handle_ = other_impl.wait_handle_;
+  other_impl.wait_handle_ = INVALID_HANDLE_VALUE;
+  impl.op_queue_.push(other_impl.op_queue_);
+  impl.owner_ = this;
+
+  if (this != &other_service)
+  {
+    // Insert implementation into linked list of all implementations.
+    impl.next_ = other_service.impl_list_;
+    impl.prev_ = 0;
+    if (other_service.impl_list_)
+      other_service.impl_list_->prev_ = &impl;
+    other_service.impl_list_ = &impl;
+  }
+
+  // We must not hold the lock while calling UnregisterWaitEx. This is because
+  // the registered callback function might be invoked while we are waiting for
+  // UnregisterWaitEx to complete.
+  lock.unlock();
+
+  if (impl.wait_handle_ != INVALID_HANDLE_VALUE)
+    ::UnregisterWaitEx(impl.wait_handle_, INVALID_HANDLE_VALUE);
+
+  if (!impl.op_queue_.empty())
+    register_wait_callback(impl, lock);
+}
+
+void win_object_handle_service::destroy(
+    win_object_handle_service::implementation_type& impl)
+{
+  mutex::scoped_lock lock(mutex_);
+
+  // Remove implementation from linked list of all implementations.
+  if (impl_list_ == &impl)
+    impl_list_ = impl.next_;
+  if (impl.prev_)
+    impl.prev_->next_ = impl.next_;
+  if (impl.next_)
+    impl.next_->prev_= impl.prev_;
+  impl.next_ = 0;
+  impl.prev_ = 0;
+
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((io_context_.context(), "object_handle",
+          &impl, reinterpret_cast<uintmax_t>(impl.wait_handle_), "close"));
+
+    HANDLE wait_handle = impl.wait_handle_;
+    impl.wait_handle_ = INVALID_HANDLE_VALUE;
+
+    op_queue<operation> ops;
+    while (wait_op* op = impl.op_queue_.front())
+    {
+      op->ec_ = asio::error::operation_aborted;
+      impl.op_queue_.pop();
+      ops.push(op);
+    }
+
+    // We must not hold the lock while calling UnregisterWaitEx. This is
+    // because the registered callback function might be invoked while we are
+    // waiting for UnregisterWaitEx to complete.
+    lock.unlock();
+
+    if (wait_handle != INVALID_HANDLE_VALUE)
+      ::UnregisterWaitEx(wait_handle, INVALID_HANDLE_VALUE);
+
+    ::CloseHandle(impl.handle_);
+    impl.handle_ = INVALID_HANDLE_VALUE;
+
+    io_context_.post_deferred_completions(ops);
+  }
+}
+
+asio::error_code win_object_handle_service::assign(
+    win_object_handle_service::implementation_type& impl,
+    const native_handle_type& handle, asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ec = asio::error::already_open;
+    return ec;
+  }
+
+  impl.handle_ = handle;
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code win_object_handle_service::close(
+    win_object_handle_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((io_context_.context(), "object_handle",
+          &impl, reinterpret_cast<uintmax_t>(impl.wait_handle_), "close"));
+
+    mutex::scoped_lock lock(mutex_);
+
+    HANDLE wait_handle = impl.wait_handle_;
+    impl.wait_handle_ = INVALID_HANDLE_VALUE;
+
+    op_queue<operation> completed_ops;
+    while (wait_op* op = impl.op_queue_.front())
+    {
+      impl.op_queue_.pop();
+      op->ec_ = asio::error::operation_aborted;
+      completed_ops.push(op);
+    }
+
+    // We must not hold the lock while calling UnregisterWaitEx. This is
+    // because the registered callback function might be invoked while we are
+    // waiting for UnregisterWaitEx to complete.
+    lock.unlock();
+
+    if (wait_handle != INVALID_HANDLE_VALUE)
+      ::UnregisterWaitEx(wait_handle, INVALID_HANDLE_VALUE);
+
+    if (::CloseHandle(impl.handle_))
+    {
+      impl.handle_ = INVALID_HANDLE_VALUE;
+      ec = asio::error_code();
+    }
+    else
+    {
+      DWORD last_error = ::GetLastError();
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+    }
+
+    io_context_.post_deferred_completions(completed_ops);
+  }
+  else
+  {
+    ec = asio::error_code();
+  }
+
+  return ec;
+}
+
+asio::error_code win_object_handle_service::cancel(
+    win_object_handle_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (is_open(impl))
+  {
+    ASIO_HANDLER_OPERATION((io_context_.context(), "object_handle",
+          &impl, reinterpret_cast<uintmax_t>(impl.wait_handle_), "cancel"));
+
+    mutex::scoped_lock lock(mutex_);
+
+    HANDLE wait_handle = impl.wait_handle_;
+    impl.wait_handle_ = INVALID_HANDLE_VALUE;
+
+    op_queue<operation> completed_ops;
+    while (wait_op* op = impl.op_queue_.front())
+    {
+      op->ec_ = asio::error::operation_aborted;
+      impl.op_queue_.pop();
+      completed_ops.push(op);
+    }
+
+    // We must not hold the lock while calling UnregisterWaitEx. This is
+    // because the registered callback function might be invoked while we are
+    // waiting for UnregisterWaitEx to complete.
+    lock.unlock();
+
+    if (wait_handle != INVALID_HANDLE_VALUE)
+      ::UnregisterWaitEx(wait_handle, INVALID_HANDLE_VALUE);
+
+    ec = asio::error_code();
+
+    io_context_.post_deferred_completions(completed_ops);
+  }
+  else
+  {
+    ec = asio::error::bad_descriptor;
+  }
+
+  return ec;
+}
+
+void win_object_handle_service::wait(
+    win_object_handle_service::implementation_type& impl,
+    asio::error_code& ec)
+{
+  switch (::WaitForSingleObject(impl.handle_, INFINITE))
+  {
+  case WAIT_FAILED:
+    {
+      DWORD last_error = ::GetLastError();
+      ec = asio::error_code(last_error,
+          asio::error::get_system_category());
+      break;
+    }
+  case WAIT_OBJECT_0:
+  case WAIT_ABANDONED:
+  default:
+    ec = asio::error_code();
+    break;
+  }
+}
+
+void win_object_handle_service::start_wait_op(
+    win_object_handle_service::implementation_type& impl, wait_op* op)
+{
+  io_context_.work_started();
+
+  if (is_open(impl))
+  {
+    mutex::scoped_lock lock(mutex_);
+
+    if (!shutdown_)
+    {
+      impl.op_queue_.push(op);
+
+      // Only the first operation to be queued gets to register a wait callback.
+      // Subsequent operations have to wait for the first to finish.
+      if (impl.op_queue_.front() == op)
+        register_wait_callback(impl, lock);
+    }
+    else
+    {
+      lock.unlock();
+      io_context_.post_deferred_completion(op);
+    }
+  }
+  else
+  {
+    op->ec_ = asio::error::bad_descriptor;
+    io_context_.post_deferred_completion(op);
+  }
+}
+
+void win_object_handle_service::register_wait_callback(
+    win_object_handle_service::implementation_type& impl,
+    mutex::scoped_lock& lock)
+{
+  lock.lock();
+
+  if (!RegisterWaitForSingleObject(&impl.wait_handle_,
+        impl.handle_, &win_object_handle_service::wait_callback,
+        &impl, INFINITE, WT_EXECUTEONLYONCE))
+  {
+    DWORD last_error = ::GetLastError();
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+
+    op_queue<operation> completed_ops;
+    while (wait_op* op = impl.op_queue_.front())
+    {
+      op->ec_ = ec;
+      impl.op_queue_.pop();
+      completed_ops.push(op);
+    }
+
+    lock.unlock();
+    io_context_.post_deferred_completions(completed_ops);
+  }
+}
+
+void win_object_handle_service::wait_callback(PVOID param, BOOLEAN)
+{
+  implementation_type* impl = static_cast<implementation_type*>(param);
+  mutex::scoped_lock lock(impl->owner_->mutex_);
+
+  if (impl->wait_handle_ != INVALID_HANDLE_VALUE)
+  {
+    ::UnregisterWaitEx(impl->wait_handle_, NULL);
+    impl->wait_handle_ = INVALID_HANDLE_VALUE;
+  }
+
+  if (wait_op* op = impl->op_queue_.front())
+  {
+    op_queue<operation> completed_ops;
+
+    op->ec_ = asio::error_code();
+    impl->op_queue_.pop();
+    completed_ops.push(op);
+
+    if (!impl->op_queue_.empty())
+    {
+      if (!RegisterWaitForSingleObject(&impl->wait_handle_,
+            impl->handle_, &win_object_handle_service::wait_callback,
+            param, INFINITE, WT_EXECUTEONLYONCE))
+      {
+        DWORD last_error = ::GetLastError();
+        asio::error_code ec(last_error,
+            asio::error::get_system_category());
+
+        while ((op = impl->op_queue_.front()) != 0)
+        {
+          op->ec_ = ec;
+          impl->op_queue_.pop();
+          completed_ops.push(op);
+        }
+      }
+    }
+
+    io_context_impl& ioc = impl->owner_->io_context_;
+    lock.unlock();
+    ioc.post_deferred_completions(completed_ops);
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+
+#endif // ASIO_DETAIL_IMPL_WIN_OBJECT_HANDLE_SERVICE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_static_mutex.ipp b/subprojects/asio/include/asio/detail/impl/win_static_mutex.ipp
new file mode 100644
index 000000000..42089bd5c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_static_mutex.ipp
@@ -0,0 +1,136 @@
+//
+// detail/impl/win_static_mutex.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_STATIC_MUTEX_IPP
+#define ASIO_DETAIL_IMPL_WIN_STATIC_MUTEX_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include <cstdio>
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_static_mutex.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+void win_static_mutex::init()
+{
+  int error = do_init();
+  asio::error_code ec(error,
+      asio::error::get_system_category());
+  asio::detail::throw_error(ec, "static_mutex");
+}
+
+int win_static_mutex::do_init()
+{
+  using namespace std; // For sprintf.
+  wchar_t mutex_name[128];
+#if defined(ASIO_HAS_SECURE_RTL)
+  swprintf_s(
+#else // defined(ASIO_HAS_SECURE_RTL)
+  _snwprintf(
+#endif // defined(ASIO_HAS_SECURE_RTL)
+      mutex_name, 128, L"asio-58CCDC44-6264-4842-90C2-F3C545CB8AA7-%u-%p",
+      static_cast<unsigned int>(::GetCurrentProcessId()), this);
+
+#if defined(ASIO_WINDOWS_APP)
+  HANDLE mutex = ::CreateMutexExW(0, mutex_name, CREATE_MUTEX_INITIAL_OWNER, 0);
+#else // defined(ASIO_WINDOWS_APP)
+  HANDLE mutex = ::CreateMutexW(0, TRUE, mutex_name);
+#endif // defined(ASIO_WINDOWS_APP)
+  DWORD last_error = ::GetLastError();
+  if (mutex == 0)
+    return ::GetLastError();
+
+  if (last_error == ERROR_ALREADY_EXISTS)
+  {
+#if defined(ASIO_WINDOWS_APP)
+    ::WaitForSingleObjectEx(mutex, INFINITE, false);
+#else // defined(ASIO_WINDOWS_APP)
+    ::WaitForSingleObject(mutex, INFINITE);
+#endif // defined(ASIO_WINDOWS_APP)
+  }
+
+  if (initialised_)
+  {
+    ::ReleaseMutex(mutex);
+    ::CloseHandle(mutex);
+    return 0;
+  }
+
+#if defined(__MINGW32__)
+  // Not sure if MinGW supports structured exception handling, so for now
+  // we'll just call the Windows API and hope.
+# if defined(UNDER_CE)
+  ::InitializeCriticalSection(&crit_section_);
+# else
+  if (!::InitializeCriticalSectionAndSpinCount(&crit_section_, 0x80000000))
+  {
+    last_error = ::GetLastError();
+    ::ReleaseMutex(mutex);
+    ::CloseHandle(mutex);
+    return last_error;
+  }
+# endif
+#else
+  __try
+  {
+# if defined(UNDER_CE)
+    ::InitializeCriticalSection(&crit_section_);
+# elif defined(ASIO_WINDOWS_APP)
+    if (!::InitializeCriticalSectionEx(&crit_section_, 0, 0))
+    {
+      last_error = ::GetLastError();
+      ::ReleaseMutex(mutex);
+      ::CloseHandle(mutex);
+      return last_error;
+    }
+# else
+    if (!::InitializeCriticalSectionAndSpinCount(&crit_section_, 0x80000000))
+    {
+      last_error = ::GetLastError();
+      ::ReleaseMutex(mutex);
+      ::CloseHandle(mutex);
+      return last_error;
+    }
+# endif
+  }
+  __except(GetExceptionCode() == STATUS_NO_MEMORY
+      ? EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH)
+  {
+    ::ReleaseMutex(mutex);
+    ::CloseHandle(mutex);
+    return ERROR_OUTOFMEMORY;
+  }
+#endif
+
+  initialised_ = true;
+  ::ReleaseMutex(mutex);
+  ::CloseHandle(mutex);
+  return 0;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_IMPL_WIN_STATIC_MUTEX_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_thread.ipp b/subprojects/asio/include/asio/detail/impl/win_thread.ipp
new file mode 100644
index 000000000..ed6dbafe0
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_thread.ipp
@@ -0,0 +1,150 @@
+//
+// detail/impl/win_thread.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_THREAD_IPP
+#define ASIO_DETAIL_IMPL_WIN_THREAD_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_APP) \
+  && !defined(UNDER_CE)
+
+#include <process.h>
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_thread.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+win_thread::~win_thread()
+{
+  ::CloseHandle(thread_);
+
+  // The exit_event_ handle is deliberately allowed to leak here since it
+  // is an error for the owner of an internal thread not to join() it.
+}
+
+void win_thread::join()
+{
+  HANDLE handles[2] = { exit_event_, thread_ };
+  ::WaitForMultipleObjects(2, handles, FALSE, INFINITE);
+  ::CloseHandle(exit_event_);
+  if (terminate_threads())
+  {
+    ::TerminateThread(thread_, 0);
+  }
+  else
+  {
+    ::QueueUserAPC(apc_function, thread_, 0);
+    ::WaitForSingleObject(thread_, INFINITE);
+  }
+}
+
+std::size_t win_thread::hardware_concurrency()
+{
+  SYSTEM_INFO system_info;
+  ::GetSystemInfo(&system_info);
+  return system_info.dwNumberOfProcessors;
+}
+
+void win_thread::start_thread(func_base* arg, unsigned int stack_size)
+{
+  ::HANDLE entry_event = 0;
+  arg->entry_event_ = entry_event = ::CreateEventW(0, true, false, 0);
+  if (!entry_event)
+  {
+    DWORD last_error = ::GetLastError();
+    delete arg;
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "thread.entry_event");
+  }
+
+  arg->exit_event_ = exit_event_ = ::CreateEventW(0, true, false, 0);
+  if (!exit_event_)
+  {
+    DWORD last_error = ::GetLastError();
+    delete arg;
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "thread.exit_event");
+  }
+
+  unsigned int thread_id = 0;
+  thread_ = reinterpret_cast<HANDLE>(::_beginthreadex(0,
+        stack_size, win_thread_function, arg, 0, &thread_id));
+  if (!thread_)
+  {
+    DWORD last_error = ::GetLastError();
+    delete arg;
+    if (entry_event)
+      ::CloseHandle(entry_event);
+    if (exit_event_)
+      ::CloseHandle(exit_event_);
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "thread");
+  }
+
+  if (entry_event)
+  {
+    ::WaitForSingleObject(entry_event, INFINITE);
+    ::CloseHandle(entry_event);
+  }
+}
+
+unsigned int __stdcall win_thread_function(void* arg)
+{
+  win_thread::auto_func_base_ptr func = {
+      static_cast<win_thread::func_base*>(arg) };
+
+  ::SetEvent(func.ptr->entry_event_);
+
+  func.ptr->run();
+
+  // Signal that the thread has finished its work, but rather than returning go
+  // to sleep to put the thread into a well known state. If the thread is being
+  // joined during global object destruction then it may be killed using
+  // TerminateThread (to avoid a deadlock in DllMain). Otherwise, the SleepEx
+  // call will be interrupted using QueueUserAPC and the thread will shut down
+  // cleanly.
+  HANDLE exit_event = func.ptr->exit_event_;
+  delete func.ptr;
+  func.ptr = 0;
+  ::SetEvent(exit_event);
+  ::SleepEx(INFINITE, TRUE);
+
+  return 0;
+}
+
+#if defined(WINVER) && (WINVER < 0x0500)
+void __stdcall apc_function(ULONG) {}
+#else
+void __stdcall apc_function(ULONG_PTR) {}
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS)
+       // && !defined(ASIO_WINDOWS_APP)
+       // && !defined(UNDER_CE)
+
+#endif // ASIO_DETAIL_IMPL_WIN_THREAD_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/win_tss_ptr.ipp b/subprojects/asio/include/asio/detail/impl/win_tss_ptr.ipp
new file mode 100644
index 000000000..61df0ce26
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/win_tss_ptr.ipp
@@ -0,0 +1,57 @@
+//
+// detail/impl/win_tss_ptr.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WIN_TSS_PTR_IPP
+#define ASIO_DETAIL_IMPL_WIN_TSS_PTR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_tss_ptr.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+DWORD win_tss_ptr_create()
+{
+#if defined(UNDER_CE)
+  const DWORD out_of_indexes = 0xFFFFFFFF;
+#else
+  const DWORD out_of_indexes = TLS_OUT_OF_INDEXES;
+#endif
+
+  DWORD tss_key = ::TlsAlloc();
+  if (tss_key == out_of_indexes)
+  {
+    DWORD last_error = ::GetLastError();
+    asio::error_code ec(last_error,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "tss");
+  }
+  return tss_key;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_IMPL_WIN_TSS_PTR_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/winrt_ssocket_service_base.ipp b/subprojects/asio/include/asio/detail/impl/winrt_ssocket_service_base.ipp
new file mode 100644
index 000000000..288ca8b13
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/winrt_ssocket_service_base.ipp
@@ -0,0 +1,629 @@
+//
+// detail/impl/winrt_ssocket_service_base.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WINRT_SSOCKET_SERVICE_BASE_IPP
+#define ASIO_DETAIL_IMPL_WINRT_SSOCKET_SERVICE_BASE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include <cstring>
+#include "asio/detail/winrt_ssocket_service_base.hpp"
+#include "asio/detail/winrt_async_op.hpp"
+#include "asio/detail/winrt_utils.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+winrt_ssocket_service_base::winrt_ssocket_service_base(
+    asio::io_context& io_context)
+  : io_context_(use_service<io_context_impl>(io_context)),
+    async_manager_(use_service<winrt_async_manager>(io_context)),
+    mutex_(),
+    impl_list_(0)
+{
+}
+
+void winrt_ssocket_service_base::base_shutdown()
+{
+  // Close all implementations, causing all operations to complete.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  base_implementation_type* impl = impl_list_;
+  while (impl)
+  {
+    asio::error_code ignored_ec;
+    close(*impl, ignored_ec);
+    impl = impl->next_;
+  }
+}
+
+void winrt_ssocket_service_base::construct(
+    winrt_ssocket_service_base::base_implementation_type& impl)
+{
+  // Insert implementation into linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  impl.next_ = impl_list_;
+  impl.prev_ = 0;
+  if (impl_list_)
+    impl_list_->prev_ = &impl;
+  impl_list_ = &impl;
+}
+
+void winrt_ssocket_service_base::base_move_construct(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    winrt_ssocket_service_base::base_implementation_type& other_impl)
+{
+  impl.socket_ = other_impl.socket_;
+  other_impl.socket_ = nullptr;
+
+  // Insert implementation into linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  impl.next_ = impl_list_;
+  impl.prev_ = 0;
+  if (impl_list_)
+    impl_list_->prev_ = &impl;
+  impl_list_ = &impl;
+}
+
+void winrt_ssocket_service_base::base_move_assign(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    winrt_ssocket_service_base& other_service,
+    winrt_ssocket_service_base::base_implementation_type& other_impl)
+{
+  asio::error_code ignored_ec;
+  close(impl, ignored_ec);
+
+  if (this != &other_service)
+  {
+    // Remove implementation from linked list of all implementations.
+    asio::detail::mutex::scoped_lock lock(mutex_);
+    if (impl_list_ == &impl)
+      impl_list_ = impl.next_;
+    if (impl.prev_)
+      impl.prev_->next_ = impl.next_;
+    if (impl.next_)
+      impl.next_->prev_= impl.prev_;
+    impl.next_ = 0;
+    impl.prev_ = 0;
+  }
+
+  impl.socket_ = other_impl.socket_;
+  other_impl.socket_ = nullptr;
+
+  if (this != &other_service)
+  {
+    // Insert implementation into linked list of all implementations.
+    asio::detail::mutex::scoped_lock lock(other_service.mutex_);
+    impl.next_ = other_service.impl_list_;
+    impl.prev_ = 0;
+    if (other_service.impl_list_)
+      other_service.impl_list_->prev_ = &impl;
+    other_service.impl_list_ = &impl;
+  }
+}
+
+void winrt_ssocket_service_base::destroy(
+    winrt_ssocket_service_base::base_implementation_type& impl)
+{
+  asio::error_code ignored_ec;
+  close(impl, ignored_ec);
+
+  // Remove implementation from linked list of all implementations.
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  if (impl_list_ == &impl)
+    impl_list_ = impl.next_;
+  if (impl.prev_)
+    impl.prev_->next_ = impl.next_;
+  if (impl.next_)
+    impl.next_->prev_= impl.prev_;
+  impl.next_ = 0;
+  impl.prev_ = 0;
+}
+
+asio::error_code winrt_ssocket_service_base::close(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (impl.socket_)
+  {
+    delete impl.socket_;
+    impl.socket_ = nullptr;
+  }
+
+  ec = asio::error_code();
+  return ec;
+}
+
+winrt_ssocket_service_base::native_handle_type
+winrt_ssocket_service_base::release(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    asio::error_code& ec)
+{
+  if (!is_open(impl))
+    return nullptr;
+
+  cancel(impl, ec);
+  if (ec)
+    return nullptr;
+
+  native_handle_type tmp = impl.socket_;
+  impl.socket_ = nullptr;
+  return tmp;
+}
+
+std::size_t winrt_ssocket_service_base::do_get_endpoint(
+    const base_implementation_type& impl, bool local,
+    void* addr, std::size_t addr_len, asio::error_code& ec) const
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return addr_len;
+  }
+
+  try
+  {
+    std::string addr_string = winrt_utils::string(local
+        ? impl.socket_->Information->LocalAddress->CanonicalName
+        : impl.socket_->Information->RemoteAddress->CanonicalName);
+    unsigned short port = winrt_utils::integer(local
+        ? impl.socket_->Information->LocalPort
+        : impl.socket_->Information->RemotePort);
+    unsigned long scope = 0;
+
+    switch (reinterpret_cast<const socket_addr_type*>(addr)->sa_family)
+    {
+    case ASIO_OS_DEF(AF_INET):
+      if (addr_len < sizeof(sockaddr_in4_type))
+      {
+        ec = asio::error::invalid_argument;
+        return addr_len;
+      }
+      else
+      {
+        socket_ops::inet_pton(ASIO_OS_DEF(AF_INET), addr_string.c_str(),
+            &reinterpret_cast<sockaddr_in4_type*>(addr)->sin_addr, &scope, ec);
+        reinterpret_cast<sockaddr_in4_type*>(addr)->sin_port
+          = socket_ops::host_to_network_short(port);
+        ec = asio::error_code();
+        return sizeof(sockaddr_in4_type);
+      }
+    case ASIO_OS_DEF(AF_INET6):
+      if (addr_len < sizeof(sockaddr_in6_type))
+      {
+        ec = asio::error::invalid_argument;
+        return addr_len;
+      }
+      else
+      {
+        socket_ops::inet_pton(ASIO_OS_DEF(AF_INET6), addr_string.c_str(),
+            &reinterpret_cast<sockaddr_in6_type*>(addr)->sin6_addr, &scope, ec);
+        reinterpret_cast<sockaddr_in6_type*>(addr)->sin6_port
+          = socket_ops::host_to_network_short(port);
+        ec = asio::error_code();
+        return sizeof(sockaddr_in6_type);
+      }
+    default:
+      ec = asio::error::address_family_not_supported;
+      return addr_len;
+    }
+  }
+  catch (Platform::Exception^ e)
+  {
+    ec = asio::error_code(e->HResult,
+        asio::system_category());
+    return addr_len;
+  }
+}
+
+asio::error_code winrt_ssocket_service_base::do_set_option(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    int level, int optname, const void* optval,
+    std::size_t optlen, asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return ec;
+  }
+
+  try
+  {
+    if (level == ASIO_OS_DEF(SOL_SOCKET)
+        && optname == ASIO_OS_DEF(SO_KEEPALIVE))
+    {
+      if (optlen == sizeof(int))
+      {
+        int value = 0;
+        std::memcpy(&value, optval, optlen);
+        impl.socket_->Control->KeepAlive = !!value;
+        ec = asio::error_code();
+      }
+      else
+      {
+        ec = asio::error::invalid_argument;
+      }
+    }
+    else if (level == ASIO_OS_DEF(IPPROTO_TCP)
+        && optname == ASIO_OS_DEF(TCP_NODELAY))
+    {
+      if (optlen == sizeof(int))
+      {
+        int value = 0;
+        std::memcpy(&value, optval, optlen);
+        impl.socket_->Control->NoDelay = !!value;
+        ec = asio::error_code();
+      }
+      else
+      {
+        ec = asio::error::invalid_argument;
+      }
+    }
+    else
+    {
+      ec = asio::error::invalid_argument;
+    }
+  }
+  catch (Platform::Exception^ e)
+  {
+    ec = asio::error_code(e->HResult,
+        asio::system_category());
+  }
+
+  return ec;
+}
+
+void winrt_ssocket_service_base::do_get_option(
+    const winrt_ssocket_service_base::base_implementation_type& impl,
+    int level, int optname, void* optval,
+    std::size_t* optlen, asio::error_code& ec) const
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return;
+  }
+
+  try
+  {
+    if (level == ASIO_OS_DEF(SOL_SOCKET)
+        && optname == ASIO_OS_DEF(SO_KEEPALIVE))
+    {
+      if (*optlen >= sizeof(int))
+      {
+        int value = impl.socket_->Control->KeepAlive ? 1 : 0;
+        std::memcpy(optval, &value, sizeof(int));
+        *optlen = sizeof(int);
+        ec = asio::error_code();
+      }
+      else
+      {
+        ec = asio::error::invalid_argument;
+      }
+    }
+    else if (level == ASIO_OS_DEF(IPPROTO_TCP)
+        && optname == ASIO_OS_DEF(TCP_NODELAY))
+    {
+      if (*optlen >= sizeof(int))
+      {
+        int value = impl.socket_->Control->NoDelay ? 1 : 0;
+        std::memcpy(optval, &value, sizeof(int));
+        *optlen = sizeof(int);
+        ec = asio::error_code();
+      }
+      else
+      {
+        ec = asio::error::invalid_argument;
+      }
+    }
+    else
+    {
+      ec = asio::error::invalid_argument;
+    }
+  }
+  catch (Platform::Exception^ e)
+  {
+    ec = asio::error_code(e->HResult,
+        asio::system_category());
+  }
+}
+
+asio::error_code winrt_ssocket_service_base::do_connect(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    const void* addr, asio::error_code& ec)
+{
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return ec;
+  }
+
+  char addr_string[max_addr_v6_str_len];
+  unsigned short port;
+  switch (reinterpret_cast<const socket_addr_type*>(addr)->sa_family)
+  {
+  case ASIO_OS_DEF(AF_INET):
+    socket_ops::inet_ntop(ASIO_OS_DEF(AF_INET),
+        &reinterpret_cast<const sockaddr_in4_type*>(addr)->sin_addr,
+        addr_string, sizeof(addr_string), 0, ec);
+    port = socket_ops::network_to_host_short(
+        reinterpret_cast<const sockaddr_in4_type*>(addr)->sin_port);
+    break;
+  case ASIO_OS_DEF(AF_INET6):
+    socket_ops::inet_ntop(ASIO_OS_DEF(AF_INET6),
+        &reinterpret_cast<const sockaddr_in6_type*>(addr)->sin6_addr,
+        addr_string, sizeof(addr_string), 0, ec);
+    port = socket_ops::network_to_host_short(
+        reinterpret_cast<const sockaddr_in6_type*>(addr)->sin6_port);
+    break;
+  default:
+    ec = asio::error::address_family_not_supported;
+    return ec;
+  }
+
+  if (!ec) try
+  {
+    async_manager_.sync(impl.socket_->ConnectAsync(
+          ref new Windows::Networking::HostName(
+            winrt_utils::string(addr_string)),
+          winrt_utils::string(port)), ec);
+  }
+  catch (Platform::Exception^ e)
+  {
+    ec = asio::error_code(e->HResult,
+        asio::system_category());
+  }
+
+  return ec;
+}
+
+void winrt_ssocket_service_base::start_connect_op(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    const void* addr, winrt_async_op<void>* op, bool is_continuation)
+{
+  if (!is_open(impl))
+  {
+    op->ec_ = asio::error::bad_descriptor;
+    io_context_.post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  char addr_string[max_addr_v6_str_len];
+  unsigned short port = 0;
+  switch (reinterpret_cast<const socket_addr_type*>(addr)->sa_family)
+  {
+  case ASIO_OS_DEF(AF_INET):
+    socket_ops::inet_ntop(ASIO_OS_DEF(AF_INET),
+        &reinterpret_cast<const sockaddr_in4_type*>(addr)->sin_addr,
+        addr_string, sizeof(addr_string), 0, op->ec_);
+    port = socket_ops::network_to_host_short(
+        reinterpret_cast<const sockaddr_in4_type*>(addr)->sin_port);
+    break;
+  case ASIO_OS_DEF(AF_INET6):
+    socket_ops::inet_ntop(ASIO_OS_DEF(AF_INET6),
+        &reinterpret_cast<const sockaddr_in6_type*>(addr)->sin6_addr,
+        addr_string, sizeof(addr_string), 0, op->ec_);
+    port = socket_ops::network_to_host_short(
+        reinterpret_cast<const sockaddr_in6_type*>(addr)->sin6_port);
+    break;
+  default:
+    op->ec_ = asio::error::address_family_not_supported;
+    break;
+  }
+
+  if (op->ec_)
+  {
+    io_context_.post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  try
+  {
+    async_manager_.async(impl.socket_->ConnectAsync(
+          ref new Windows::Networking::HostName(
+            winrt_utils::string(addr_string)),
+          winrt_utils::string(port)), op);
+  }
+  catch (Platform::Exception^ e)
+  {
+    op->ec_ = asio::error_code(
+        e->HResult, asio::system_category());
+    io_context_.post_immediate_completion(op, is_continuation);
+  }
+}
+
+std::size_t winrt_ssocket_service_base::do_send(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    const asio::const_buffer& data,
+    socket_base::message_flags flags, asio::error_code& ec)
+{
+  if (flags)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  try
+  {
+    buffer_sequence_adapter<asio::const_buffer,
+      asio::const_buffer> bufs(asio::buffer(data));
+
+    if (bufs.all_empty())
+    {
+      ec = asio::error_code();
+      return 0;
+    }
+
+    return async_manager_.sync(
+        impl.socket_->OutputStream->WriteAsync(bufs.buffers()[0]), ec);
+  }
+  catch (Platform::Exception^ e)
+  {
+    ec = asio::error_code(e->HResult,
+        asio::system_category());
+    return 0;
+  }
+}
+
+void winrt_ssocket_service_base::start_send_op(
+      winrt_ssocket_service_base::base_implementation_type& impl,
+      const asio::const_buffer& data, socket_base::message_flags flags,
+      winrt_async_op<unsigned int>* op, bool is_continuation)
+{
+  if (flags)
+  {
+    op->ec_ = asio::error::operation_not_supported;
+    io_context_.post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  if (!is_open(impl))
+  {
+    op->ec_ = asio::error::bad_descriptor;
+    io_context_.post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  try
+  {
+    buffer_sequence_adapter<asio::const_buffer,
+        asio::const_buffer> bufs(asio::buffer(data));
+
+    if (bufs.all_empty())
+    {
+      io_context_.post_immediate_completion(op, is_continuation);
+      return;
+    }
+
+    async_manager_.async(
+        impl.socket_->OutputStream->WriteAsync(bufs.buffers()[0]), op);
+  }
+  catch (Platform::Exception^ e)
+  {
+    op->ec_ = asio::error_code(e->HResult,
+        asio::system_category());
+    io_context_.post_immediate_completion(op, is_continuation);
+  }
+}
+
+std::size_t winrt_ssocket_service_base::do_receive(
+    winrt_ssocket_service_base::base_implementation_type& impl,
+    const asio::mutable_buffer& data,
+    socket_base::message_flags flags, asio::error_code& ec)
+{
+  if (flags)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  if (!is_open(impl))
+  {
+    ec = asio::error::bad_descriptor;
+    return 0;
+  }
+
+  try
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        asio::mutable_buffer> bufs(asio::buffer(data));
+
+    if (bufs.all_empty())
+    {
+      ec = asio::error_code();
+      return 0;
+    }
+
+    async_manager_.sync(
+        impl.socket_->InputStream->ReadAsync(
+          bufs.buffers()[0], bufs.buffers()[0]->Capacity,
+          Windows::Storage::Streams::InputStreamOptions::Partial), ec);
+
+    std::size_t bytes_transferred = bufs.buffers()[0]->Length;
+    if (bytes_transferred == 0 && !ec)
+    {
+      ec = asio::error::eof;
+    }
+
+    return bytes_transferred;
+  }
+  catch (Platform::Exception^ e)
+  {
+    ec = asio::error_code(e->HResult,
+        asio::system_category());
+    return 0;
+  }
+}
+
+void winrt_ssocket_service_base::start_receive_op(
+      winrt_ssocket_service_base::base_implementation_type& impl,
+      const asio::mutable_buffer& data, socket_base::message_flags flags,
+      winrt_async_op<Windows::Storage::Streams::IBuffer^>* op,
+      bool is_continuation)
+{
+  if (flags)
+  {
+    op->ec_ = asio::error::operation_not_supported;
+    io_context_.post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  if (!is_open(impl))
+  {
+    op->ec_ = asio::error::bad_descriptor;
+    io_context_.post_immediate_completion(op, is_continuation);
+    return;
+  }
+
+  try
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        asio::mutable_buffer> bufs(asio::buffer(data));
+
+    if (bufs.all_empty())
+    {
+      io_context_.post_immediate_completion(op, is_continuation);
+      return;
+    }
+
+    async_manager_.async(
+        impl.socket_->InputStream->ReadAsync(
+          bufs.buffers()[0], bufs.buffers()[0]->Capacity,
+          Windows::Storage::Streams::InputStreamOptions::Partial), op);
+  }
+  catch (Platform::Exception^ e)
+  {
+    op->ec_ = asio::error_code(e->HResult,
+        asio::system_category());
+    io_context_.post_immediate_completion(op, is_continuation);
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_IMPL_WINRT_SSOCKET_SERVICE_BASE_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/winrt_timer_scheduler.hpp b/subprojects/asio/include/asio/detail/impl/winrt_timer_scheduler.hpp
new file mode 100644
index 000000000..856378feb
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/winrt_timer_scheduler.hpp
@@ -0,0 +1,92 @@
+//
+// detail/impl/winrt_timer_scheduler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WINRT_TIMER_SCHEDULER_HPP
+#define ASIO_DETAIL_IMPL_WINRT_TIMER_SCHEDULER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+void winrt_timer_scheduler::add_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_add_timer_queue(queue);
+}
+
+// Remove a timer queue from the reactor.
+template <typename Time_Traits>
+void winrt_timer_scheduler::remove_timer_queue(timer_queue<Time_Traits>& queue)
+{
+  do_remove_timer_queue(queue);
+}
+
+template <typename Time_Traits>
+void winrt_timer_scheduler::schedule_timer(timer_queue<Time_Traits>& queue,
+    const typename Time_Traits::time_type& time,
+    typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  if (shutdown_)
+  {
+    io_context_.post_immediate_completion(op, false);
+    return;
+  }
+
+  bool earliest = queue.enqueue_timer(time, timer, op);
+  io_context_.work_started();
+  if (earliest)
+    event_.signal(lock);
+}
+
+template <typename Time_Traits>
+std::size_t winrt_timer_scheduler::cancel_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& timer,
+    std::size_t max_cancelled)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  std::size_t n = queue.cancel_timer(timer, ops, max_cancelled);
+  lock.unlock();
+  io_context_.post_deferred_completions(ops);
+  return n;
+}
+
+template <typename Time_Traits>
+void winrt_timer_scheduler::move_timer(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data& to,
+    typename timer_queue<Time_Traits>::per_timer_data& from)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  queue.cancel_timer(to, ops);
+  queue.move_timer(to, from);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_IMPL_WINRT_TIMER_SCHEDULER_HPP
diff --git a/subprojects/asio/include/asio/detail/impl/winrt_timer_scheduler.ipp b/subprojects/asio/include/asio/detail/impl/winrt_timer_scheduler.ipp
new file mode 100644
index 000000000..ef2139965
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/winrt_timer_scheduler.ipp
@@ -0,0 +1,122 @@
+//
+// detail/impl/winrt_timer_scheduler.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WINRT_TIMER_SCHEDULER_IPP
+#define ASIO_DETAIL_IMPL_WINRT_TIMER_SCHEDULER_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/winrt_timer_scheduler.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+winrt_timer_scheduler::winrt_timer_scheduler(
+    asio::io_context& io_context)
+  : asio::detail::service_base<winrt_timer_scheduler>(io_context),
+    io_context_(use_service<io_context_impl>(io_context)),
+    mutex_(),
+    event_(),
+    timer_queues_(),
+    thread_(0),
+    stop_thread_(false),
+    shutdown_(false)
+{
+  thread_ = new asio::detail::thread(
+      bind_handler(&winrt_timer_scheduler::call_run_thread, this));
+}
+
+winrt_timer_scheduler::~winrt_timer_scheduler()
+{
+  shutdown();
+}
+
+void winrt_timer_scheduler::shutdown()
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  shutdown_ = true;
+  stop_thread_ = true;
+  event_.signal(lock);
+  lock.unlock();
+
+  if (thread_)
+  {
+    thread_->join();
+    delete thread_;
+    thread_ = 0;
+  }
+
+  op_queue<operation> ops;
+  timer_queues_.get_all_timers(ops);
+  io_context_.abandon_operations(ops);
+}
+
+void winrt_timer_scheduler::notify_fork(asio::io_context::fork_event)
+{
+}
+
+void winrt_timer_scheduler::init_task()
+{
+}
+
+void winrt_timer_scheduler::run_thread()
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+  while (!stop_thread_)
+  {
+    const long max_wait_duration = 5 * 60 * 1000000;
+    long wait_duration = timer_queues_.wait_duration_usec(max_wait_duration);
+    event_.wait_for_usec(lock, wait_duration);
+    event_.clear(lock);
+    op_queue<operation> ops;
+    timer_queues_.get_ready_timers(ops);
+    if (!ops.empty())
+    {
+      lock.unlock();
+      io_context_.post_deferred_completions(ops);
+      lock.lock();
+    }
+  }
+}
+
+void winrt_timer_scheduler::call_run_thread(winrt_timer_scheduler* scheduler)
+{
+  scheduler->run_thread();
+}
+
+void winrt_timer_scheduler::do_add_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.insert(&queue);
+}
+
+void winrt_timer_scheduler::do_remove_timer_queue(timer_queue_base& queue)
+{
+  mutex::scoped_lock lock(mutex_);
+  timer_queues_.erase(&queue);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_IMPL_WINRT_TIMER_SCHEDULER_IPP
diff --git a/subprojects/asio/include/asio/detail/impl/winsock_init.ipp b/subprojects/asio/include/asio/detail/impl/winsock_init.ipp
new file mode 100644
index 000000000..da4b0c0b4
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/impl/winsock_init.ipp
@@ -0,0 +1,82 @@
+//
+// detail/impl/winsock_init.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IMPL_WINSOCK_INIT_IPP
+#define ASIO_DETAIL_IMPL_WINSOCK_INIT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/winsock_init.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+void winsock_init_base::startup(data& d,
+    unsigned char major, unsigned char minor)
+{
+  if (::InterlockedIncrement(&d.init_count_) == 1)
+  {
+    WSADATA wsa_data;
+    long result = ::WSAStartup(MAKEWORD(major, minor), &wsa_data);
+    ::InterlockedExchange(&d.result_, result);
+  }
+}
+
+void winsock_init_base::manual_startup(data& d)
+{
+  if (::InterlockedIncrement(&d.init_count_) == 1)
+  {
+    ::InterlockedExchange(&d.result_, 0);
+  }
+}
+
+void winsock_init_base::cleanup(data& d)
+{
+  if (::InterlockedDecrement(&d.init_count_) == 0)
+  {
+    ::WSACleanup();
+  }
+}
+
+void winsock_init_base::manual_cleanup(data& d)
+{
+  ::InterlockedDecrement(&d.init_count_);
+}
+
+void winsock_init_base::throw_on_error(data& d)
+{
+  long result = ::InterlockedExchangeAdd(&d.result_, 0);
+  if (result != 0)
+  {
+    asio::error_code ec(result,
+        asio::error::get_system_category());
+    asio::detail::throw_error(ec, "winsock");
+  }
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_IMPL_WINSOCK_INIT_IPP
diff --git a/subprojects/asio/include/asio/detail/io_control.hpp b/subprojects/asio/include/asio/detail/io_control.hpp
new file mode 100644
index 000000000..12f35e096
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/io_control.hpp
@@ -0,0 +1,84 @@
+//
+// detail/io_control.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IO_CONTROL_HPP
+#define ASIO_DETAIL_IO_CONTROL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace io_control {
+
+// I/O control command for getting number of bytes available.
+class bytes_readable
+{
+public:
+  // Default constructor.
+  bytes_readable()
+    : value_(0)
+  {
+  }
+
+  // Construct with a specific command value.
+  bytes_readable(std::size_t value)
+    : value_(static_cast<detail::ioctl_arg_type>(value))
+  {
+  }
+
+  // Get the name of the IO control command.
+  int name() const
+  {
+    return static_cast<int>(ASIO_OS_DEF(FIONREAD));
+  }
+
+  // Set the value of the I/O control command.
+  void set(std::size_t value)
+  {
+    value_ = static_cast<detail::ioctl_arg_type>(value);
+  }
+
+  // Get the current value of the I/O control command.
+  std::size_t get() const
+  {
+    return static_cast<std::size_t>(value_);
+  }
+
+  // Get the address of the command data.
+  detail::ioctl_arg_type* data()
+  {
+    return &value_;
+  }
+
+  // Get the address of the command data.
+  const detail::ioctl_arg_type* data() const
+  {
+    return &value_;
+  }
+
+private:
+  detail::ioctl_arg_type value_;
+};
+
+} // namespace io_control
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IO_CONTROL_HPP
diff --git a/subprojects/asio/include/asio/detail/is_buffer_sequence.hpp b/subprojects/asio/include/asio/detail/is_buffer_sequence.hpp
new file mode 100644
index 000000000..69f9bbdf2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/is_buffer_sequence.hpp
@@ -0,0 +1,263 @@
+//
+// detail/is_buffer_sequence.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IS_BUFFER_SEQUENCE_HPP
+#define ASIO_DETAIL_IS_BUFFER_SEQUENCE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class mutable_buffer;
+class const_buffer;
+
+namespace detail {
+
+struct buffer_sequence_memfns_base
+{
+  void begin();
+  void end();
+  void size();
+  void max_size();
+  void capacity();
+  void data();
+  void prepare();
+  void commit();
+  void consume();
+};
+
+template <typename T>
+struct buffer_sequence_memfns_derived
+  : T, buffer_sequence_memfns_base
+{
+};
+
+template <typename T, T>
+struct buffer_sequence_memfns_check
+{
+};
+
+template <typename>
+char (&buffer_sequence_begin_helper(...))[2];
+
+#if defined(ASIO_HAS_DECLTYPE)
+
+template <typename T>
+char buffer_sequence_begin_helper(T* t,
+    typename enable_if<!is_same<
+      decltype(asio::buffer_sequence_begin(*t)),
+        void>::value>::type*);
+
+#else // defined(ASIO_HAS_DECLTYPE)
+
+template <typename T>
+char buffer_sequence_begin_helper(T* t,
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::begin>*);
+
+#endif // defined(ASIO_HAS_DECLTYPE)
+
+template <typename>
+char (&buffer_sequence_end_helper(...))[2];
+
+#if defined(ASIO_HAS_DECLTYPE)
+
+template <typename T>
+char buffer_sequence_end_helper(T* t,
+    typename enable_if<!is_same<
+      decltype(asio::buffer_sequence_end(*t)),
+        void>::value>::type*);
+
+#else // defined(ASIO_HAS_DECLTYPE)
+
+template <typename T>
+char buffer_sequence_end_helper(T* t,
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::end>*);
+
+#endif // defined(ASIO_HAS_DECLTYPE)
+
+template <typename>
+char (&size_memfn_helper(...))[2];
+
+template <typename T>
+char size_memfn_helper(
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::size>*);
+
+template <typename>
+char (&max_size_memfn_helper(...))[2];
+
+template <typename T>
+char max_size_memfn_helper(
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::max_size>*);
+
+template <typename>
+char (&capacity_memfn_helper(...))[2];
+
+template <typename T>
+char capacity_memfn_helper(
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::capacity>*);
+
+template <typename>
+char (&data_memfn_helper(...))[2];
+
+template <typename T>
+char data_memfn_helper(
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::data>*);
+
+template <typename>
+char (&prepare_memfn_helper(...))[2];
+
+template <typename T>
+char prepare_memfn_helper(
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::prepare>*);
+
+template <typename>
+char (&commit_memfn_helper(...))[2];
+
+template <typename T>
+char commit_memfn_helper(
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::commit>*);
+
+template <typename>
+char (&consume_memfn_helper(...))[2];
+
+template <typename T>
+char consume_memfn_helper(
+    buffer_sequence_memfns_check<
+      void (buffer_sequence_memfns_base::*)(),
+      &buffer_sequence_memfns_derived<T>::consume>*);
+
+template <typename, typename>
+char (&buffer_sequence_element_type_helper(...))[2];
+
+#if defined(ASIO_HAS_DECLTYPE)
+
+template <typename T, typename Buffer>
+char buffer_sequence_element_type_helper(T* t,
+    typename enable_if<is_convertible<
+      decltype(*asio::buffer_sequence_begin(*t)),
+        Buffer>::value>::type*);
+
+#else // defined(ASIO_HAS_DECLTYPE)
+
+template <typename T, typename Buffer>
+char buffer_sequence_element_type_helper(
+    typename T::const_iterator*,
+    typename enable_if<is_convertible<
+      typename T::value_type, Buffer>::value>::type*);
+
+#endif // defined(ASIO_HAS_DECLTYPE)
+
+template <typename>
+char (&const_buffers_type_typedef_helper(...))[2];
+
+template <typename T>
+char const_buffers_type_typedef_helper(
+    typename T::const_buffers_type*);
+
+template <typename>
+char (&mutable_buffers_type_typedef_helper(...))[2];
+
+template <typename T>
+char mutable_buffers_type_typedef_helper(
+    typename T::mutable_buffers_type*);
+
+template <typename T, typename Buffer>
+struct is_buffer_sequence_class
+  : integral_constant<bool,
+      sizeof(buffer_sequence_begin_helper<T>(0)) != 1 &&
+      sizeof(buffer_sequence_end_helper<T>(0)) != 1 &&
+      sizeof(buffer_sequence_element_type_helper<T, Buffer>(0, 0)) == 1>
+{
+};
+
+template <typename T, typename Buffer>
+struct is_buffer_sequence
+  : conditional<is_class<T>::value,
+      is_buffer_sequence_class<T, Buffer>,
+      false_type>::type
+{
+};
+
+template <>
+struct is_buffer_sequence<mutable_buffer, mutable_buffer>
+  : true_type
+{
+};
+
+template <>
+struct is_buffer_sequence<mutable_buffer, const_buffer>
+  : true_type
+{
+};
+
+template <>
+struct is_buffer_sequence<const_buffer, const_buffer>
+  : true_type
+{
+};
+
+template <>
+struct is_buffer_sequence<const_buffer, mutable_buffer>
+  : false_type
+{
+};
+
+template <typename T>
+struct is_dynamic_buffer_class
+  : integral_constant<bool,
+      sizeof(size_memfn_helper<T>(0)) != 1 &&
+      sizeof(max_size_memfn_helper<T>(0)) != 1 &&
+      sizeof(capacity_memfn_helper<T>(0)) != 1 &&
+      sizeof(data_memfn_helper<T>(0)) != 1 &&
+      sizeof(consume_memfn_helper<T>(0)) != 1 &&
+      sizeof(prepare_memfn_helper<T>(0)) != 1 &&
+      sizeof(commit_memfn_helper<T>(0)) != 1 &&
+      sizeof(const_buffers_type_typedef_helper<T>(0)) == 1 &&
+      sizeof(mutable_buffers_type_typedef_helper<T>(0)) == 1>
+{
+};
+
+template <typename T>
+struct is_dynamic_buffer
+  : conditional<is_class<T>::value,
+      is_dynamic_buffer_class<T>,
+      false_type>::type
+{
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IS_BUFFER_SEQUENCE_HPP
diff --git a/subprojects/asio/include/asio/detail/is_executor.hpp b/subprojects/asio/include/asio/detail/is_executor.hpp
new file mode 100644
index 000000000..4584dd04b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/is_executor.hpp
@@ -0,0 +1,126 @@
+//
+// detail/is_executor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_IS_EXECUTOR_HPP
+#define ASIO_DETAIL_IS_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct executor_memfns_base
+{
+  void context();
+  void on_work_started();
+  void on_work_finished();
+  void dispatch();
+  void post();
+  void defer();
+};
+
+template <typename T>
+struct executor_memfns_derived
+  : T, executor_memfns_base
+{
+};
+
+template <typename T, T>
+struct executor_memfns_check
+{
+};
+
+template <typename>
+char (&context_memfn_helper(...))[2];
+
+template <typename T>
+char context_memfn_helper(
+    executor_memfns_check<
+      void (executor_memfns_base::*)(),
+      &executor_memfns_derived<T>::context>*);
+
+template <typename>
+char (&on_work_started_memfn_helper(...))[2];
+
+template <typename T>
+char on_work_started_memfn_helper(
+    executor_memfns_check<
+      void (executor_memfns_base::*)(),
+      &executor_memfns_derived<T>::on_work_started>*);
+
+template <typename>
+char (&on_work_finished_memfn_helper(...))[2];
+
+template <typename T>
+char on_work_finished_memfn_helper(
+    executor_memfns_check<
+      void (executor_memfns_base::*)(),
+      &executor_memfns_derived<T>::on_work_finished>*);
+
+template <typename>
+char (&dispatch_memfn_helper(...))[2];
+
+template <typename T>
+char dispatch_memfn_helper(
+    executor_memfns_check<
+      void (executor_memfns_base::*)(),
+      &executor_memfns_derived<T>::dispatch>*);
+
+template <typename>
+char (&post_memfn_helper(...))[2];
+
+template <typename T>
+char post_memfn_helper(
+    executor_memfns_check<
+      void (executor_memfns_base::*)(),
+      &executor_memfns_derived<T>::post>*);
+
+template <typename>
+char (&defer_memfn_helper(...))[2];
+
+template <typename T>
+char defer_memfn_helper(
+    executor_memfns_check<
+      void (executor_memfns_base::*)(),
+      &executor_memfns_derived<T>::defer>*);
+
+template <typename T>
+struct is_executor_class
+  : integral_constant<bool,
+      sizeof(context_memfn_helper<T>(0)) != 1 &&
+      sizeof(on_work_started_memfn_helper<T>(0)) != 1 &&
+      sizeof(on_work_finished_memfn_helper<T>(0)) != 1 &&
+      sizeof(dispatch_memfn_helper<T>(0)) != 1 &&
+      sizeof(post_memfn_helper<T>(0)) != 1 &&
+      sizeof(defer_memfn_helper<T>(0)) != 1>
+{
+};
+
+template <typename T>
+struct is_executor
+  : conditional<is_class<T>::value,
+      is_executor_class<T>,
+      false_type>::type
+{
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IS_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/keyword_tss_ptr.hpp b/subprojects/asio/include/asio/detail/keyword_tss_ptr.hpp
new file mode 100644
index 000000000..2ae651ab2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/keyword_tss_ptr.hpp
@@ -0,0 +1,70 @@
+//
+// detail/keyword_tss_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_KEYWORD_TSS_PTR_HPP
+#define ASIO_DETAIL_KEYWORD_TSS_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_THREAD_KEYWORD_EXTENSION)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+class keyword_tss_ptr
+  : private noncopyable
+{
+public:
+  // Constructor.
+  keyword_tss_ptr()
+  {
+  }
+
+  // Destructor.
+  ~keyword_tss_ptr()
+  {
+  }
+
+  // Get the value.
+  operator T*() const
+  {
+    return value_;
+  }
+
+  // Set the value.
+  void operator=(T* value)
+  {
+    value_ = value;
+  }
+
+private:
+  static ASIO_THREAD_KEYWORD T* value_;
+};
+
+template <typename T>
+ASIO_THREAD_KEYWORD T* keyword_tss_ptr<T>::value_;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_THREAD_KEYWORD_EXTENSION)
+
+#endif // ASIO_DETAIL_KEYWORD_TSS_PTR_HPP
diff --git a/subprojects/asio/include/asio/detail/kqueue_reactor.hpp b/subprojects/asio/include/asio/detail/kqueue_reactor.hpp
new file mode 100644
index 000000000..43cb9f935
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/kqueue_reactor.hpp
@@ -0,0 +1,242 @@
+//
+// detail/kqueue_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2005 Stefan Arentz (stefan at soze dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_KQUEUE_REACTOR_HPP
+#define ASIO_DETAIL_KQUEUE_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_KQUEUE)
+
+#include <cstddef>
+#include <sys/types.h>
+#include <sys/event.h>
+#include <sys/time.h>
+#include "asio/detail/limits.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/object_pool.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/select_interrupter.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+#include "asio/detail/timer_queue_set.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/error.hpp"
+#include "asio/execution_context.hpp"
+
+// Older versions of Mac OS X may not define EV_OOBAND.
+#if !defined(EV_OOBAND)
+# define EV_OOBAND EV_FLAG1
+#endif // !defined(EV_OOBAND)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class scheduler;
+
+class kqueue_reactor
+  : public execution_context_service_base<kqueue_reactor>
+{
+private:
+  // The mutex type used by this reactor.
+  typedef conditionally_enabled_mutex mutex;
+
+public:
+  enum op_types { read_op = 0, write_op = 1,
+    connect_op = 1, except_op = 2, max_ops = 3 };
+
+  // Per-descriptor queues.
+  struct descriptor_state
+  {
+    descriptor_state(bool locking) : mutex_(locking) {}
+
+    friend class kqueue_reactor;
+    friend class object_pool_access;
+
+    descriptor_state* next_;
+    descriptor_state* prev_;
+
+    mutex mutex_;
+    int descriptor_;
+    int num_kevents_; // 1 == read only, 2 == read and write
+    op_queue<reactor_op> op_queue_[max_ops];
+    bool shutdown_;
+  };
+
+  // Per-descriptor data.
+  typedef descriptor_state* per_descriptor_data;
+
+  // Constructor.
+  ASIO_DECL kqueue_reactor(asio::execution_context& ctx);
+
+  // Destructor.
+  ASIO_DECL ~kqueue_reactor();
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Recreate internal descriptors following a fork.
+  ASIO_DECL void notify_fork(
+      asio::execution_context::fork_event fork_ev);
+
+  // Initialise the task.
+  ASIO_DECL void init_task();
+
+  // Register a socket with the reactor. Returns 0 on success, system error
+  // code on failure.
+  ASIO_DECL int register_descriptor(socket_type descriptor,
+      per_descriptor_data& descriptor_data);
+
+  // Register a descriptor with an associated single operation. Returns 0 on
+  // success, system error code on failure.
+  ASIO_DECL int register_internal_descriptor(
+      int op_type, socket_type descriptor,
+      per_descriptor_data& descriptor_data, reactor_op* op);
+
+  // Move descriptor registration from one descriptor_data object to another.
+  ASIO_DECL void move_descriptor(socket_type descriptor,
+      per_descriptor_data& target_descriptor_data,
+      per_descriptor_data& source_descriptor_data);
+
+  // Post a reactor operation for immediate completion.
+  void post_immediate_completion(reactor_op* op, bool is_continuation)
+  {
+    scheduler_.post_immediate_completion(op, is_continuation);
+  }
+
+  // Start a new operation. The reactor operation will be performed when the
+  // given descriptor is flagged as ready, or an error has occurred.
+  ASIO_DECL void start_op(int op_type, socket_type descriptor,
+      per_descriptor_data& descriptor_data, reactor_op* op,
+      bool is_continuation, bool allow_speculative);
+
+  // Cancel all operations associated with the given descriptor. The
+  // handlers associated with the descriptor will be invoked with the
+  // operation_aborted error.
+  ASIO_DECL void cancel_ops(socket_type descriptor,
+      per_descriptor_data& descriptor_data);
+
+  // Cancel any operations that are running against the descriptor and remove
+  // its registration from the reactor. The reactor resources associated with
+  // the descriptor must be released by calling cleanup_descriptor_data.
+  ASIO_DECL void deregister_descriptor(socket_type descriptor,
+      per_descriptor_data& descriptor_data, bool closing);
+
+  // Remove the descriptor's registration from the reactor. The reactor
+  // resources associated with the descriptor must be released by calling
+  // cleanup_descriptor_data.
+  ASIO_DECL void deregister_internal_descriptor(
+      socket_type descriptor, per_descriptor_data& descriptor_data);
+
+  // Perform any post-deregistration cleanup tasks associated with the
+  // descriptor data.
+  ASIO_DECL void cleanup_descriptor_data(
+      per_descriptor_data& descriptor_data);
+
+  // Add a new timer queue to the reactor.
+  template <typename Time_Traits>
+  void add_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Remove a timer queue from the reactor.
+  template <typename Time_Traits>
+  void remove_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Schedule a new operation in the given timer queue to expire at the
+  // specified absolute time.
+  template <typename Time_Traits>
+  void schedule_timer(timer_queue<Time_Traits>& queue,
+      const typename Time_Traits::time_type& time,
+      typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
+
+  // Cancel the timer operations associated with the given token. Returns the
+  // number of operations that have been posted or dispatched.
+  template <typename Time_Traits>
+  std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& timer,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
+
+  // Move the timer operations associated with the given timer.
+  template <typename Time_Traits>
+  void move_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& target,
+      typename timer_queue<Time_Traits>::per_timer_data& source);
+
+  // Run the kqueue loop.
+  ASIO_DECL void run(long usec, op_queue<operation>& ops);
+
+  // Interrupt the kqueue loop.
+  ASIO_DECL void interrupt();
+
+private:
+  // Create the kqueue file descriptor. Throws an exception if the descriptor
+  // cannot be created.
+  ASIO_DECL static int do_kqueue_create();
+
+  // Allocate a new descriptor state object.
+  ASIO_DECL descriptor_state* allocate_descriptor_state();
+
+  // Free an existing descriptor state object.
+  ASIO_DECL void free_descriptor_state(descriptor_state* s);
+
+  // Helper function to add a new timer queue.
+  ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
+
+  // Helper function to remove a timer queue.
+  ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
+
+  // Get the timeout value for the kevent call.
+  ASIO_DECL timespec* get_timeout(long usec, timespec& ts);
+
+  // The scheduler used to post completions.
+  scheduler& scheduler_;
+
+  // Mutex to protect access to internal data.
+  mutex mutex_;
+
+  // The kqueue file descriptor.
+  int kqueue_fd_;
+
+  // The interrupter is used to break a blocking kevent call.
+  select_interrupter interrupter_;
+
+  // The timer queues.
+  timer_queue_set timer_queues_;
+
+  // Whether the service has been shut down.
+  bool shutdown_;
+
+  // Mutex to protect access to the registered descriptors.
+  mutex registered_descriptors_mutex_;
+
+  // Keep track of all registered descriptors.
+  object_pool<descriptor_state> registered_descriptors_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/kqueue_reactor.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/kqueue_reactor.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_KQUEUE)
+
+#endif // ASIO_DETAIL_KQUEUE_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/limits.hpp b/subprojects/asio/include/asio/detail/limits.hpp
new file mode 100644
index 000000000..d32470d2d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/limits.hpp
@@ -0,0 +1,26 @@
+//
+// detail/limits.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2011 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_LIMITS_HPP
+#define ASIO_DETAIL_LIMITS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_LIMITS)
+# include <boost/limits.hpp>
+#else // defined(ASIO_HAS_BOOST_LIMITS)
+# include <limits>
+#endif // defined(ASIO_HAS_BOOST_LIMITS)
+
+#endif // ASIO_DETAIL_LIMITS_HPP
diff --git a/subprojects/asio/include/asio/detail/local_free_on_block_exit.hpp b/subprojects/asio/include/asio/detail/local_free_on_block_exit.hpp
new file mode 100644
index 000000000..eba6b7771
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/local_free_on_block_exit.hpp
@@ -0,0 +1,59 @@
+//
+// detail/local_free_on_block_exit.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_LOCAL_FREE_ON_BLOCK_EXIT_HPP
+#define ASIO_DETAIL_LOCAL_FREE_ON_BLOCK_EXIT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+#if !defined(ASIO_WINDOWS_APP)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class local_free_on_block_exit
+  : private noncopyable
+{
+public:
+  // Constructor blocks all signals for the calling thread.
+  explicit local_free_on_block_exit(void* p)
+    : p_(p)
+  {
+  }
+
+  // Destructor restores the previous signal mask.
+  ~local_free_on_block_exit()
+  {
+    ::LocalFree(p_);
+  }
+
+private:
+  void* p_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS_APP)
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_LOCAL_FREE_ON_BLOCK_EXIT_HPP
diff --git a/subprojects/asio/include/asio/detail/macos_fenced_block.hpp b/subprojects/asio/include/asio/detail/macos_fenced_block.hpp
new file mode 100644
index 000000000..bbac270a4
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/macos_fenced_block.hpp
@@ -0,0 +1,62 @@
+//
+// detail/macos_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_MACOS_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_MACOS_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(__MACH__) && defined(__APPLE__)
+
+#include <libkern/OSAtomic.h>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class macos_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_t { half };
+  enum full_t { full };
+
+  // Constructor for a half fenced block.
+  explicit macos_fenced_block(half_t)
+  {
+  }
+
+  // Constructor for a full fenced block.
+  explicit macos_fenced_block(full_t)
+  {
+    OSMemoryBarrier();
+  }
+
+  // Destructor.
+  ~macos_fenced_block()
+  {
+    OSMemoryBarrier();
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(__MACH__) && defined(__APPLE__)
+
+#endif // ASIO_DETAIL_MACOS_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/memory.hpp b/subprojects/asio/include/asio/detail/memory.hpp
new file mode 100644
index 000000000..b1ec4975f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/memory.hpp
@@ -0,0 +1,70 @@
+//
+// detail/memory.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_MEMORY_HPP
+#define ASIO_DETAIL_MEMORY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <memory>
+
+#if !defined(ASIO_HAS_STD_SHARED_PTR)
+# include <boost/shared_ptr.hpp>
+# include <boost/weak_ptr.hpp>
+#endif // !defined(ASIO_HAS_STD_SHARED_PTR)
+
+#if !defined(ASIO_HAS_STD_ADDRESSOF)
+# include <boost/utility/addressof.hpp>
+#endif // !defined(ASIO_HAS_STD_ADDRESSOF)
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_STD_SHARED_PTR)
+using std::shared_ptr;
+using std::weak_ptr;
+#else // defined(ASIO_HAS_STD_SHARED_PTR)
+using boost::shared_ptr;
+using boost::weak_ptr;
+#endif // defined(ASIO_HAS_STD_SHARED_PTR)
+
+#if defined(ASIO_HAS_STD_ADDRESSOF)
+using std::addressof;
+#else // defined(ASIO_HAS_STD_ADDRESSOF)
+using boost::addressof;
+#endif // defined(ASIO_HAS_STD_ADDRESSOF)
+
+} // namespace detail
+
+#if defined(ASIO_HAS_CXX11_ALLOCATORS)
+using std::allocator_arg_t;
+# define ASIO_USES_ALLOCATOR(t) \
+  namespace std { \
+    template <typename Allocator> \
+    struct uses_allocator<t, Allocator> : true_type {}; \
+  } \
+  /**/
+# define ASIO_REBIND_ALLOC(alloc, t) \
+  typename std::allocator_traits<alloc>::template rebind_alloc<t>
+  /**/
+#else // defined(ASIO_HAS_CXX11_ALLOCATORS)
+struct allocator_arg_t {};
+# define ASIO_USES_ALLOCATOR(t)
+# define ASIO_REBIND_ALLOC(alloc, t) \
+  typename alloc::template rebind<t>::other
+  /**/
+#endif // defined(ASIO_HAS_CXX11_ALLOCATORS)
+
+} // namespace asio
+
+#endif // ASIO_DETAIL_MEMORY_HPP
diff --git a/subprojects/asio/include/asio/detail/mutex.hpp b/subprojects/asio/include/asio/detail/mutex.hpp
new file mode 100644
index 000000000..2f8f0b132
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/mutex.hpp
@@ -0,0 +1,48 @@
+//
+// detail/mutex.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_MUTEX_HPP
+#define ASIO_DETAIL_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+# include "asio/detail/null_mutex.hpp"
+#elif defined(ASIO_WINDOWS)
+# include "asio/detail/win_mutex.hpp"
+#elif defined(ASIO_HAS_PTHREADS)
+# include "asio/detail/posix_mutex.hpp"
+#elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+# include "asio/detail/std_mutex.hpp"
+#else
+# error Only Windows, POSIX and std::mutex are supported!
+#endif
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS)
+typedef null_mutex mutex;
+#elif defined(ASIO_WINDOWS)
+typedef win_mutex mutex;
+#elif defined(ASIO_HAS_PTHREADS)
+typedef posix_mutex mutex;
+#elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+typedef std_mutex mutex;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/noncopyable.hpp b/subprojects/asio/include/asio/detail/noncopyable.hpp
new file mode 100644
index 000000000..0c038e11e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/noncopyable.hpp
@@ -0,0 +1,43 @@
+//
+// detail/noncopyable.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NONCOPYABLE_HPP
+#define ASIO_DETAIL_NONCOPYABLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class noncopyable
+{
+protected:
+  noncopyable() {}
+  ~noncopyable() {}
+private:
+  noncopyable(const noncopyable&);
+  const noncopyable& operator=(const noncopyable&);
+};
+
+} // namespace detail
+
+using asio::detail::noncopyable;
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_NONCOPYABLE_HPP
diff --git a/subprojects/asio/include/asio/detail/null_event.hpp b/subprojects/asio/include/asio/detail/null_event.hpp
new file mode 100644
index 000000000..5686a41e7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_event.hpp
@@ -0,0 +1,100 @@
+//
+// detail/null_event.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_EVENT_HPP
+#define ASIO_DETAIL_NULL_EVENT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class null_event
+  : private noncopyable
+{
+public:
+  // Constructor.
+  null_event()
+  {
+  }
+
+  // Destructor.
+  ~null_event()
+  {
+  }
+
+  // Signal the event. (Retained for backward compatibility.)
+  template <typename Lock>
+  void signal(Lock&)
+  {
+  }
+
+  // Signal all waiters.
+  template <typename Lock>
+  void signal_all(Lock&)
+  {
+  }
+
+  // Unlock the mutex and signal one waiter.
+  template <typename Lock>
+  void unlock_and_signal_one(Lock&)
+  {
+  }
+
+  // If there's a waiter, unlock the mutex and signal it.
+  template <typename Lock>
+  bool maybe_unlock_and_signal_one(Lock&)
+  {
+    return false;
+  }
+
+  // Reset the event.
+  template <typename Lock>
+  void clear(Lock&)
+  {
+  }
+
+  // Wait for the event to become signalled.
+  template <typename Lock>
+  void wait(Lock&)
+  {
+    do_wait();
+  }
+
+  // Timed wait for the event to become signalled.
+  template <typename Lock>
+  bool wait_for_usec(Lock&, long usec)
+  {
+    do_wait_for_usec(usec);
+    return true;
+  }
+
+private:
+  ASIO_DECL static void do_wait();
+  ASIO_DECL static void do_wait_for_usec(long usec);
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/null_event.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_NULL_EVENT_HPP
diff --git a/subprojects/asio/include/asio/detail/null_fenced_block.hpp b/subprojects/asio/include/asio/detail/null_fenced_block.hpp
new file mode 100644
index 000000000..0275326b1
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_fenced_block.hpp
@@ -0,0 +1,47 @@
+//
+// detail/null_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_NULL_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class null_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_or_full_t { half, full };
+
+  // Constructor.
+  explicit null_fenced_block(half_or_full_t)
+  {
+  }
+
+  // Destructor.
+  ~null_fenced_block()
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_NULL_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/null_global.hpp b/subprojects/asio/include/asio/detail/null_global.hpp
new file mode 100644
index 000000000..727dd3f49
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_global.hpp
@@ -0,0 +1,59 @@
+//
+// detail/null_global.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_GLOBAL_HPP
+#define ASIO_DETAIL_NULL_GLOBAL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+struct null_global_impl
+{
+  null_global_impl()
+    : ptr_(0)
+  {
+  }
+
+  // Destructor automatically cleans up the global.
+  ~null_global_impl()
+  {
+    delete ptr_;
+  }
+
+  static null_global_impl instance_;
+  T* ptr_;
+};
+
+template <typename T>
+null_global_impl<T> null_global_impl<T>::instance_;
+
+template <typename T>
+T& null_global()
+{
+  if (null_global_impl<T>::instance_.ptr_ == 0)
+    null_global_impl<T>::instance_.ptr_ = new T;
+  return *null_global_impl<T>::instance_.ptr_;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_NULL_GLOBAL_HPP
diff --git a/subprojects/asio/include/asio/detail/null_mutex.hpp b/subprojects/asio/include/asio/detail/null_mutex.hpp
new file mode 100644
index 000000000..afe3fc032
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_mutex.hpp
@@ -0,0 +1,64 @@
+//
+// detail/null_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_MUTEX_HPP
+#define ASIO_DETAIL_NULL_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class null_mutex
+  : private noncopyable
+{
+public:
+  typedef asio::detail::scoped_lock<null_mutex> scoped_lock;
+
+  // Constructor.
+  null_mutex()
+  {
+  }
+
+  // Destructor.
+  ~null_mutex()
+  {
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_THREADS)
+
+#endif // ASIO_DETAIL_NULL_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/null_reactor.hpp b/subprojects/asio/include/asio/detail/null_reactor.hpp
new file mode 100644
index 000000000..ca3c5fde6
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_reactor.hpp
@@ -0,0 +1,68 @@
+//
+// detail/null_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_REACTOR_HPP
+#define ASIO_DETAIL_NULL_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP) || defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/scheduler_operation.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class null_reactor
+  : public execution_context_service_base<null_reactor>
+{
+public:
+  // Constructor.
+  null_reactor(asio::execution_context& ctx)
+    : execution_context_service_base<null_reactor>(ctx)
+  {
+  }
+
+  // Destructor.
+  ~null_reactor()
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+  }
+
+  // No-op because should never be called.
+  void run(long /*usec*/, op_queue<scheduler_operation>& /*ops*/)
+  {
+  }
+
+  // No-op.
+  void interrupt()
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP) || defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_NULL_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/null_signal_blocker.hpp b/subprojects/asio/include/asio/detail/null_signal_blocker.hpp
new file mode 100644
index 000000000..edfe82051
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_signal_blocker.hpp
@@ -0,0 +1,69 @@
+//
+// detail/null_signal_blocker.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_SIGNAL_BLOCKER_HPP
+#define ASIO_DETAIL_NULL_SIGNAL_BLOCKER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS) \
+  || defined(ASIO_WINDOWS) \
+  || defined(ASIO_WINDOWS_RUNTIME) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class null_signal_blocker
+  : private noncopyable
+{
+public:
+  // Constructor blocks all signals for the calling thread.
+  null_signal_blocker()
+  {
+  }
+
+  // Destructor restores the previous signal mask.
+  ~null_signal_blocker()
+  {
+  }
+
+  // Block all signals for the calling thread.
+  void block()
+  {
+  }
+
+  // Restore the previous signal mask.
+  void unblock()
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_THREADS)
+       // || defined(ASIO_WINDOWS)
+       // || defined(ASIO_WINDOWS_RUNTIME)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+
+#endif // ASIO_DETAIL_NULL_SIGNAL_BLOCKER_HPP
diff --git a/subprojects/asio/include/asio/detail/null_socket_service.hpp b/subprojects/asio/include/asio/detail/null_socket_service.hpp
new file mode 100644
index 000000000..109c6c7bd
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_socket_service.hpp
@@ -0,0 +1,508 @@
+//
+// detail/null_socket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_SOCKET_SERVICE_HPP
+#define ASIO_DETAIL_NULL_SOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/buffer.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/socket_base.hpp"
+#include "asio/detail/bind_handler.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol>
+class null_socket_service :
+  public service_base<null_socket_service<Protocol> >
+{
+public:
+  // The protocol type.
+  typedef Protocol protocol_type;
+
+  // The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  // The native type of a socket.
+  typedef int native_handle_type;
+
+  // The implementation type of the socket.
+  struct implementation_type
+  {
+  };
+
+  // Constructor.
+  null_socket_service(asio::io_context& io_context)
+    : service_base<null_socket_service<Protocol> >(io_context),
+      io_context_(io_context)
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+  }
+
+  // Construct a new socket implementation.
+  void construct(implementation_type&)
+  {
+  }
+
+  // Move-construct a new socket implementation.
+  void move_construct(implementation_type&, implementation_type&)
+  {
+  }
+
+  // Move-assign from another socket implementation.
+  void move_assign(implementation_type&,
+      null_socket_service&, implementation_type&)
+  {
+  }
+
+  // Move-construct a new socket implementation from another protocol type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type&,
+      null_socket_service<Protocol1>&,
+      typename null_socket_service<Protocol1>::implementation_type&)
+  {
+  }
+
+  // Destroy a socket implementation.
+  void destroy(implementation_type&)
+  {
+  }
+
+  // Open a new socket implementation.
+  asio::error_code open(implementation_type&,
+      const protocol_type&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Assign a native socket to a socket implementation.
+  asio::error_code assign(implementation_type&, const protocol_type&,
+      const native_handle_type&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Determine whether the socket is open.
+  bool is_open(const implementation_type&) const
+  {
+    return false;
+  }
+
+  // Destroy a socket implementation.
+  asio::error_code close(implementation_type&,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Release ownership of the socket.
+  native_handle_type release(implementation_type&,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Get the native socket representation.
+  native_handle_type native_handle(implementation_type&)
+  {
+    return 0;
+  }
+
+  // Cancel all operations associated with the socket.
+  asio::error_code cancel(implementation_type&,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const implementation_type&,
+      asio::error_code& ec) const
+  {
+    ec = asio::error::operation_not_supported;
+    return false;
+  }
+
+  // Determine the number of bytes available for reading.
+  std::size_t available(const implementation_type&,
+      asio::error_code& ec) const
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Place the socket into the state where it will listen for new connections.
+  asio::error_code listen(implementation_type&,
+      int, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Perform an IO control command on the socket.
+  template <typename IO_Control_Command>
+  asio::error_code io_control(implementation_type&,
+      IO_Control_Command&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the socket.
+  bool non_blocking(const implementation_type&) const
+  {
+    return false;
+  }
+
+  // Sets the non-blocking mode of the socket.
+  asio::error_code non_blocking(implementation_type&,
+      bool, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const implementation_type&) const
+  {
+    return false;
+  }
+
+  // Sets the non-blocking mode of the native socket implementation.
+  asio::error_code native_non_blocking(implementation_type&,
+      bool, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Disable sends or receives on the socket.
+  asio::error_code shutdown(implementation_type&,
+      socket_base::shutdown_type, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Bind the socket to the specified local endpoint.
+  asio::error_code bind(implementation_type&,
+      const endpoint_type&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Set a socket option.
+  template <typename Option>
+  asio::error_code set_option(implementation_type&,
+      const Option&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Set a socket option.
+  template <typename Option>
+  asio::error_code get_option(const implementation_type&,
+      Option&, asio::error_code& ec) const
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type&,
+      asio::error_code& ec) const
+  {
+    ec = asio::error::operation_not_supported;
+    return endpoint_type();
+  }
+
+  // Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type&,
+      asio::error_code& ec) const
+  {
+    ec = asio::error::operation_not_supported;
+    return endpoint_type();
+  }
+
+  // Send the given data to the peer.
+  template <typename ConstBufferSequence>
+  std::size_t send(implementation_type&, const ConstBufferSequence&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Wait until data can be sent without blocking.
+  std::size_t send(implementation_type&, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Start an asynchronous send. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_send(implementation_type&, const ConstBufferSequence&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Start an asynchronous wait until data can be sent without blocking.
+  template <typename Handler>
+  void async_send(implementation_type&, const null_buffers&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Receive some data from the peer. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  std::size_t receive(implementation_type&, const MutableBufferSequence&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Wait until data can be received without blocking.
+  std::size_t receive(implementation_type&, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive(implementation_type&, const MutableBufferSequence&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive(implementation_type&, const null_buffers&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Receive some data with associated flags. Returns the number of bytes
+  // received.
+  template <typename MutableBufferSequence>
+  std::size_t receive_with_flags(implementation_type&,
+      const MutableBufferSequence&, socket_base::message_flags,
+      socket_base::message_flags&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Wait until data can be received without blocking.
+  std::size_t receive_with_flags(implementation_type&,
+      const null_buffers&, socket_base::message_flags,
+      socket_base::message_flags&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive_with_flags(implementation_type&,
+      const MutableBufferSequence&, socket_base::message_flags,
+      socket_base::message_flags&, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive_with_flags(implementation_type&,
+      const null_buffers&, socket_base::message_flags,
+      socket_base::message_flags&, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Send a datagram to the specified endpoint. Returns the number of bytes
+  // sent.
+  template <typename ConstBufferSequence>
+  std::size_t send_to(implementation_type&, const ConstBufferSequence&,
+      const endpoint_type&, socket_base::message_flags,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Wait until data can be sent without blocking.
+  std::size_t send_to(implementation_type&, const null_buffers&,
+      const endpoint_type&, socket_base::message_flags,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Start an asynchronous send. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_send_to(implementation_type&, const ConstBufferSequence&,
+      const endpoint_type&, socket_base::message_flags,
+      Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Start an asynchronous wait until data can be sent without blocking.
+  template <typename Handler>
+  void async_send_to(implementation_type&, const null_buffers&,
+      const endpoint_type&, socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Receive a datagram with the endpoint of the sender. Returns the number of
+  // bytes received.
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(implementation_type&, const MutableBufferSequence&,
+      endpoint_type&, socket_base::message_flags,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Wait until data can be received without blocking.
+  std::size_t receive_from(implementation_type&, const null_buffers&,
+      endpoint_type&, socket_base::message_flags,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received and
+  // the sender_endpoint object must both be valid for the lifetime of the
+  // asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive_from(implementation_type&,
+      const MutableBufferSequence&, endpoint_type&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive_from(implementation_type&,
+      const null_buffers&, endpoint_type&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.post(detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Accept a new connection.
+  template <typename Socket>
+  asio::error_code accept(implementation_type&,
+      Socket&, endpoint_type*, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Start an asynchronous accept. The peer and peer_endpoint objects
+  // must be valid until the accept's handler is invoked.
+  template <typename Socket, typename Handler>
+  void async_accept(implementation_type&, Socket&,
+      endpoint_type*, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    io_context_.post(detail::bind_handler(handler, ec));
+  }
+
+  // Connect the socket to the specified endpoint.
+  asio::error_code connect(implementation_type&,
+      const endpoint_type&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Start an asynchronous connect.
+  template <typename Handler>
+  void async_connect(implementation_type&,
+      const endpoint_type&, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    io_context_.post(detail::bind_handler(handler, ec));
+  }
+
+private:
+  asio::io_context& io_context_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_NULL_SOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/null_static_mutex.hpp b/subprojects/asio/include/asio/detail/null_static_mutex.hpp
new file mode 100644
index 000000000..36ec04f7e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_static_mutex.hpp
@@ -0,0 +1,60 @@
+//
+// detail/null_static_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_STATIC_MUTEX_HPP
+#define ASIO_DETAIL_NULL_STATIC_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct null_static_mutex
+{
+  typedef asio::detail::scoped_lock<null_static_mutex> scoped_lock;
+
+  // Initialise the mutex.
+  void init()
+  {
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+  }
+
+  int unused_;
+};
+
+#define ASIO_NULL_STATIC_MUTEX_INIT { 0 }
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_THREADS)
+
+#endif // ASIO_DETAIL_NULL_STATIC_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/null_thread.hpp b/subprojects/asio/include/asio/detail/null_thread.hpp
new file mode 100644
index 000000000..7291ba384
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_thread.hpp
@@ -0,0 +1,67 @@
+//
+// detail/null_thread.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_THREAD_HPP
+#define ASIO_DETAIL_NULL_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class null_thread
+  : private noncopyable
+{
+public:
+  // Constructor.
+  template <typename Function>
+  null_thread(Function, unsigned int = 0)
+  {
+    asio::detail::throw_error(
+        asio::error::operation_not_supported, "thread");
+  }
+
+  // Destructor.
+  ~null_thread()
+  {
+  }
+
+  // Wait for the thread to exit.
+  void join()
+  {
+  }
+
+  // Get number of CPUs.
+  static std::size_t hardware_concurrency()
+  {
+    return 1;
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_THREADS)
+
+#endif // ASIO_DETAIL_NULL_THREAD_HPP
diff --git a/subprojects/asio/include/asio/detail/null_tss_ptr.hpp b/subprojects/asio/include/asio/detail/null_tss_ptr.hpp
new file mode 100644
index 000000000..323967d6c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/null_tss_ptr.hpp
@@ -0,0 +1,68 @@
+//
+// detail/null_tss_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_NULL_TSS_PTR_HPP
+#define ASIO_DETAIL_NULL_TSS_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+class null_tss_ptr
+  : private noncopyable
+{
+public:
+  // Constructor.
+  null_tss_ptr()
+    : value_(0)
+  {
+  }
+
+  // Destructor.
+  ~null_tss_ptr()
+  {
+  }
+
+  // Get the value.
+  operator T*() const
+  {
+    return value_;
+  }
+
+  // Set the value.
+  void operator=(T* value)
+  {
+    value_ = value;
+  }
+
+private:
+  T* value_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_THREADS)
+
+#endif // ASIO_DETAIL_NULL_TSS_PTR_HPP
diff --git a/subprojects/asio/include/asio/detail/object_pool.hpp b/subprojects/asio/include/asio/detail/object_pool.hpp
new file mode 100644
index 000000000..e1a3c5482
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/object_pool.hpp
@@ -0,0 +1,171 @@
+//
+// detail/object_pool.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_OBJECT_POOL_HPP
+#define ASIO_DETAIL_OBJECT_POOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Object>
+class object_pool;
+
+class object_pool_access
+{
+public:
+  template <typename Object>
+  static Object* create()
+  {
+    return new Object;
+  }
+
+  template <typename Object, typename Arg>
+  static Object* create(Arg arg)
+  {
+    return new Object(arg);
+  }
+
+  template <typename Object>
+  static void destroy(Object* o)
+  {
+    delete o;
+  }
+
+  template <typename Object>
+  static Object*& next(Object* o)
+  {
+    return o->next_;
+  }
+
+  template <typename Object>
+  static Object*& prev(Object* o)
+  {
+    return o->prev_;
+  }
+};
+
+template <typename Object>
+class object_pool
+  : private noncopyable
+{
+public:
+  // Constructor.
+  object_pool()
+    : live_list_(0),
+      free_list_(0)
+  {
+  }
+
+  // Destructor destroys all objects.
+  ~object_pool()
+  {
+    destroy_list(live_list_);
+    destroy_list(free_list_);
+  }
+
+  // Get the object at the start of the live list.
+  Object* first()
+  {
+    return live_list_;
+  }
+
+  // Allocate a new object.
+  Object* alloc()
+  {
+    Object* o = free_list_;
+    if (o)
+      free_list_ = object_pool_access::next(free_list_);
+    else
+      o = object_pool_access::create<Object>();
+
+    object_pool_access::next(o) = live_list_;
+    object_pool_access::prev(o) = 0;
+    if (live_list_)
+      object_pool_access::prev(live_list_) = o;
+    live_list_ = o;
+
+    return o;
+  }
+
+  // Allocate a new object with an argument.
+  template <typename Arg>
+  Object* alloc(Arg arg)
+  {
+    Object* o = free_list_;
+    if (o)
+      free_list_ = object_pool_access::next(free_list_);
+    else
+      o = object_pool_access::create<Object>(arg);
+
+    object_pool_access::next(o) = live_list_;
+    object_pool_access::prev(o) = 0;
+    if (live_list_)
+      object_pool_access::prev(live_list_) = o;
+    live_list_ = o;
+
+    return o;
+  }
+
+  // Free an object. Moves it to the free list. No destructors are run.
+  void free(Object* o)
+  {
+    if (live_list_ == o)
+      live_list_ = object_pool_access::next(o);
+
+    if (object_pool_access::prev(o))
+    {
+      object_pool_access::next(object_pool_access::prev(o))
+        = object_pool_access::next(o);
+    }
+
+    if (object_pool_access::next(o))
+    {
+      object_pool_access::prev(object_pool_access::next(o))
+        = object_pool_access::prev(o);
+    }
+
+    object_pool_access::next(o) = free_list_;
+    object_pool_access::prev(o) = 0;
+    free_list_ = o;
+  }
+
+private:
+  // Helper function to destroy all elements in a list.
+  void destroy_list(Object* list)
+  {
+    while (list)
+    {
+      Object* o = list;
+      list = object_pool_access::next(o);
+      object_pool_access::destroy(o);
+    }
+  }
+
+  // The list of live objects.
+  Object* live_list_;
+
+  // The free list.
+  Object* free_list_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_OBJECT_POOL_HPP
diff --git a/subprojects/asio/include/asio/detail/old_win_sdk_compat.hpp b/subprojects/asio/include/asio/detail/old_win_sdk_compat.hpp
new file mode 100644
index 000000000..bfb109e7f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/old_win_sdk_compat.hpp
@@ -0,0 +1,214 @@
+//
+// detail/old_win_sdk_compat.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_OLD_WIN_SDK_COMPAT_HPP
+#define ASIO_DETAIL_OLD_WIN_SDK_COMPAT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+// Guess whether we are building against on old Platform SDK.
+#if !defined(IN6ADDR_ANY_INIT)
+#define ASIO_HAS_OLD_WIN_SDK 1
+#endif // !defined(IN6ADDR_ANY_INIT)
+
+#if defined(ASIO_HAS_OLD_WIN_SDK)
+
+// Emulation of types that are missing from old Platform SDKs.
+//
+// N.B. this emulation is also used if building for a Windows 2000 target with
+// a recent (i.e. Vista or later) SDK, as the SDK does not provide IPv6 support
+// in that case.
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+enum
+{
+  sockaddr_storage_maxsize = 128, // Maximum size.
+  sockaddr_storage_alignsize = (sizeof(__int64)), // Desired alignment.
+  sockaddr_storage_pad1size = (sockaddr_storage_alignsize - sizeof(short)),
+  sockaddr_storage_pad2size = (sockaddr_storage_maxsize -
+      (sizeof(short) + sockaddr_storage_pad1size + sockaddr_storage_alignsize))
+};
+
+struct sockaddr_storage_emulation
+{
+  short ss_family;
+  char __ss_pad1[sockaddr_storage_pad1size];
+  __int64 __ss_align;
+  char __ss_pad2[sockaddr_storage_pad2size];
+};
+
+struct in6_addr_emulation
+{
+  union
+  {
+    u_char Byte[16];
+    u_short Word[8];
+  } u;
+};
+
+#if !defined(s6_addr)
+# define _S6_un u
+# define _S6_u8 Byte
+# define s6_addr _S6_un._S6_u8
+#endif // !defined(s6_addr)
+
+struct sockaddr_in6_emulation
+{
+  short sin6_family;
+  u_short sin6_port;
+  u_long sin6_flowinfo;
+  in6_addr_emulation sin6_addr;
+  u_long sin6_scope_id;
+};
+
+struct ipv6_mreq_emulation
+{
+  in6_addr_emulation ipv6mr_multiaddr;
+  unsigned int ipv6mr_interface;
+};
+
+struct addrinfo_emulation
+{
+  int ai_flags;
+  int ai_family;
+  int ai_socktype;
+  int ai_protocol;
+  size_t ai_addrlen;
+  char* ai_canonname;
+  sockaddr* ai_addr;
+  addrinfo_emulation* ai_next;
+};
+
+#if !defined(AI_PASSIVE)
+# define AI_PASSIVE 0x1
+#endif
+
+#if !defined(AI_CANONNAME)
+# define AI_CANONNAME 0x2
+#endif
+
+#if !defined(AI_NUMERICHOST)
+# define AI_NUMERICHOST 0x4
+#endif
+
+#if !defined(EAI_AGAIN)
+# define EAI_AGAIN WSATRY_AGAIN
+#endif
+
+#if !defined(EAI_BADFLAGS)
+# define EAI_BADFLAGS WSAEINVAL
+#endif
+
+#if !defined(EAI_FAIL)
+# define EAI_FAIL WSANO_RECOVERY
+#endif
+
+#if !defined(EAI_FAMILY)
+# define EAI_FAMILY WSAEAFNOSUPPORT
+#endif
+
+#if !defined(EAI_MEMORY)
+# define EAI_MEMORY WSA_NOT_ENOUGH_MEMORY
+#endif
+
+#if !defined(EAI_NODATA)
+# define EAI_NODATA WSANO_DATA
+#endif
+
+#if !defined(EAI_NONAME)
+# define EAI_NONAME WSAHOST_NOT_FOUND
+#endif
+
+#if !defined(EAI_SERVICE)
+# define EAI_SERVICE WSATYPE_NOT_FOUND
+#endif
+
+#if !defined(EAI_SOCKTYPE)
+# define EAI_SOCKTYPE WSAESOCKTNOSUPPORT
+#endif
+
+#if !defined(NI_NOFQDN)
+# define NI_NOFQDN 0x01
+#endif
+
+#if !defined(NI_NUMERICHOST)
+# define NI_NUMERICHOST 0x02
+#endif
+
+#if !defined(NI_NAMEREQD)
+# define NI_NAMEREQD 0x04
+#endif
+
+#if !defined(NI_NUMERICSERV)
+# define NI_NUMERICSERV 0x08
+#endif
+
+#if !defined(NI_DGRAM)
+# define NI_DGRAM 0x10
+#endif
+
+#if !defined(IPPROTO_IPV6)
+# define IPPROTO_IPV6 41
+#endif
+
+#if !defined(IPV6_UNICAST_HOPS)
+# define IPV6_UNICAST_HOPS 4
+#endif
+
+#if !defined(IPV6_MULTICAST_IF)
+# define IPV6_MULTICAST_IF 9
+#endif
+
+#if !defined(IPV6_MULTICAST_HOPS)
+# define IPV6_MULTICAST_HOPS 10
+#endif
+
+#if !defined(IPV6_MULTICAST_LOOP)
+# define IPV6_MULTICAST_LOOP 11
+#endif
+
+#if !defined(IPV6_JOIN_GROUP)
+# define IPV6_JOIN_GROUP 12
+#endif
+
+#if !defined(IPV6_LEAVE_GROUP)
+# define IPV6_LEAVE_GROUP 13
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_OLD_WIN_SDK)
+
+// Even newer Platform SDKs that support IPv6 may not define IPV6_V6ONLY.
+#if !defined(IPV6_V6ONLY)
+# define IPV6_V6ONLY 27
+#endif
+
+// Some SDKs (e.g. Windows CE) don't define IPPROTO_ICMPV6.
+#if !defined(IPPROTO_ICMPV6)
+# define IPPROTO_ICMPV6 58
+#endif
+
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_OLD_WIN_SDK_COMPAT_HPP
diff --git a/subprojects/asio/include/asio/detail/op_queue.hpp b/subprojects/asio/include/asio/detail/op_queue.hpp
new file mode 100644
index 000000000..6219f797d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/op_queue.hpp
@@ -0,0 +1,162 @@
+//
+// detail/op_queue.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_OP_QUEUE_HPP
+#define ASIO_DETAIL_OP_QUEUE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Operation>
+class op_queue;
+
+class op_queue_access
+{
+public:
+  template <typename Operation>
+  static Operation* next(Operation* o)
+  {
+    return static_cast<Operation*>(o->next_);
+  }
+
+  template <typename Operation1, typename Operation2>
+  static void next(Operation1*& o1, Operation2* o2)
+  {
+    o1->next_ = o2;
+  }
+
+  template <typename Operation>
+  static void destroy(Operation* o)
+  {
+    o->destroy();
+  }
+
+  template <typename Operation>
+  static Operation*& front(op_queue<Operation>& q)
+  {
+    return q.front_;
+  }
+
+  template <typename Operation>
+  static Operation*& back(op_queue<Operation>& q)
+  {
+    return q.back_;
+  }
+};
+
+template <typename Operation>
+class op_queue
+  : private noncopyable
+{
+public:
+  // Constructor.
+  op_queue()
+    : front_(0),
+      back_(0)
+  {
+  }
+
+  // Destructor destroys all operations.
+  ~op_queue()
+  {
+    while (Operation* op = front_)
+    {
+      pop();
+      op_queue_access::destroy(op);
+    }
+  }
+
+  // Get the operation at the front of the queue.
+  Operation* front()
+  {
+    return front_;
+  }
+
+  // Pop an operation from the front of the queue.
+  void pop()
+  {
+    if (front_)
+    {
+      Operation* tmp = front_;
+      front_ = op_queue_access::next(front_);
+      if (front_ == 0)
+        back_ = 0;
+      op_queue_access::next(tmp, static_cast<Operation*>(0));
+    }
+  }
+
+  // Push an operation on to the back of the queue.
+  void push(Operation* h)
+  {
+    op_queue_access::next(h, static_cast<Operation*>(0));
+    if (back_)
+    {
+      op_queue_access::next(back_, h);
+      back_ = h;
+    }
+    else
+    {
+      front_ = back_ = h;
+    }
+  }
+
+  // Push all operations from another queue on to the back of the queue. The
+  // source queue may contain operations of a derived type.
+  template <typename OtherOperation>
+  void push(op_queue<OtherOperation>& q)
+  {
+    if (Operation* other_front = op_queue_access::front(q))
+    {
+      if (back_)
+        op_queue_access::next(back_, other_front);
+      else
+        front_ = other_front;
+      back_ = op_queue_access::back(q);
+      op_queue_access::front(q) = 0;
+      op_queue_access::back(q) = 0;
+    }
+  }
+
+  // Whether the queue is empty.
+  bool empty() const
+  {
+    return front_ == 0;
+  }
+
+  // Test whether an operation is already enqueued.
+  bool is_enqueued(Operation* o) const
+  {
+    return op_queue_access::next(o) != 0 || back_ == o;
+  }
+
+private:
+  friend class op_queue_access;
+
+  // The front of the queue.
+  Operation* front_;
+
+  // The back of the queue.
+  Operation* back_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_OP_QUEUE_HPP
diff --git a/subprojects/asio/include/asio/detail/operation.hpp b/subprojects/asio/include/asio/detail/operation.hpp
new file mode 100644
index 000000000..811e54d4a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/operation.hpp
@@ -0,0 +1,38 @@
+//
+// detail/operation.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_OPERATION_HPP
+#define ASIO_DETAIL_OPERATION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_operation.hpp"
+#else
+# include "asio/detail/scheduler_operation.hpp"
+#endif
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_IOCP)
+typedef win_iocp_operation operation;
+#else
+typedef scheduler_operation operation;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_OPERATION_HPP
diff --git a/subprojects/asio/include/asio/detail/pipe_select_interrupter.hpp b/subprojects/asio/include/asio/detail/pipe_select_interrupter.hpp
new file mode 100644
index 000000000..55d7db491
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/pipe_select_interrupter.hpp
@@ -0,0 +1,89 @@
+//
+// detail/pipe_select_interrupter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_PIPE_SELECT_INTERRUPTER_HPP
+#define ASIO_DETAIL_PIPE_SELECT_INTERRUPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS)
+#if !defined(ASIO_WINDOWS_RUNTIME)
+#if !defined(__CYGWIN__)
+#if !defined(__SYMBIAN32__)
+#if !defined(ASIO_HAS_EVENTFD)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class pipe_select_interrupter
+{
+public:
+  // Constructor.
+  ASIO_DECL pipe_select_interrupter();
+
+  // Destructor.
+  ASIO_DECL ~pipe_select_interrupter();
+
+  // Recreate the interrupter's descriptors. Used after a fork.
+  ASIO_DECL void recreate();
+
+  // Interrupt the select call.
+  ASIO_DECL void interrupt();
+
+  // Reset the select interrupt. Returns true if the call was interrupted.
+  ASIO_DECL bool reset();
+
+  // Get the read descriptor to be passed to select.
+  int read_descriptor() const
+  {
+    return read_descriptor_;
+  }
+
+private:
+  // Open the descriptors. Throws on error.
+  ASIO_DECL void open_descriptors();
+
+  // Close the descriptors.
+  ASIO_DECL void close_descriptors();
+
+  // The read end of a connection used to interrupt the select call. This file
+  // descriptor is passed to select such that when it is time to stop, a single
+  // byte will be written on the other end of the connection and this
+  // descriptor will become readable.
+  int read_descriptor_;
+
+  // The write end of a connection used to interrupt the select call. A single
+  // byte may be written to this to wake up the select which is waiting for the
+  // other end to become readable.
+  int write_descriptor_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/pipe_select_interrupter.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // !defined(ASIO_HAS_EVENTFD)
+#endif // !defined(__SYMBIAN32__)
+#endif // !defined(__CYGWIN__)
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+#endif // !defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_PIPE_SELECT_INTERRUPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/pop_options.hpp b/subprojects/asio/include/asio/detail/pop_options.hpp
new file mode 100644
index 000000000..1045612bf
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/pop_options.hpp
@@ -0,0 +1,135 @@
+//
+// detail/pop_options.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+// No header guard
+
+#if defined(__COMO__)
+
+// Comeau C++
+
+#elif defined(__DMC__)
+
+// Digital Mars C++
+
+#elif defined(__INTEL_COMPILER) || defined(__ICL) \
+  || defined(__ICC) || defined(__ECC)
+
+// Intel C++
+
+# if (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+#  pragma GCC visibility pop
+# endif // (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+
+#elif defined(__clang__)
+
+// Clang
+
+# if defined(__OBJC__)
+#  if !defined(__APPLE_CC__) || (__APPLE_CC__ <= 1)
+#   if defined(ASIO_OBJC_WORKAROUND)
+#    undef Protocol
+#    undef id
+#    undef ASIO_OBJC_WORKAROUND
+#   endif
+#  endif
+# endif
+
+# if !defined(_WIN32) && !defined(__WIN32__) && !defined(WIN32)
+#  pragma GCC visibility pop
+# endif // !defined(_WIN32) && !defined(__WIN32__) && !defined(WIN32)
+
+#elif defined(__GNUC__)
+
+// GNU C++
+
+# if defined(__MINGW32__) || defined(__CYGWIN__)
+#  pragma pack (pop)
+# endif
+
+# if defined(__OBJC__)
+#  if !defined(__APPLE_CC__) || (__APPLE_CC__ <= 1)
+#   if defined(ASIO_OBJC_WORKAROUND)
+#    undef Protocol
+#    undef id
+#    undef ASIO_OBJC_WORKAROUND
+#   endif
+#  endif
+# endif
+
+# if (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+#  pragma GCC visibility pop
+# endif // (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+
+# if (__GNUC__ >= 7)
+#  pragma GCC diagnostic pop
+# endif // (__GNUC__ >= 7)
+
+#elif defined(__KCC)
+
+// Kai C++
+
+#elif defined(__sgi)
+
+// SGI MIPSpro C++
+
+#elif defined(__DECCXX)
+
+// Compaq Tru64 Unix cxx
+
+#elif defined(__ghs)
+
+// Greenhills C++
+
+#elif defined(__BORLANDC__)
+
+// Borland C++
+
+# pragma option pop
+# pragma nopushoptwarn
+# pragma nopackwarning
+
+#elif defined(__MWERKS__)
+
+// Metrowerks CodeWarrior
+
+#elif defined(__SUNPRO_CC)
+
+// Sun Workshop Compiler C++
+
+#elif defined(__HP_aCC)
+
+// HP aCC
+
+#elif defined(__MRC__) || defined(__SC__)
+
+// MPW MrCpp or SCpp
+
+#elif defined(__IBMCPP__)
+
+// IBM Visual Age
+
+#elif defined(_MSC_VER)
+
+// Microsoft Visual C++
+//
+// Must remain the last #elif since some other vendors (Metrowerks, for example)
+// also #define _MSC_VER
+
+# pragma warning (pop)
+# pragma pack (pop)
+
+# if defined(__cplusplus_cli) || defined(__cplusplus_winrt)
+#  if defined(ASIO_CLR_WORKAROUND)
+#   undef generic
+#   undef ASIO_CLR_WORKAROUND
+#  endif
+# endif
+
+#endif
diff --git a/subprojects/asio/include/asio/detail/posix_event.hpp b/subprojects/asio/include/asio/detail/posix_event.hpp
new file mode 100644
index 000000000..121065efb
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_event.hpp
@@ -0,0 +1,162 @@
+//
+// detail/posix_event.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_EVENT_HPP
+#define ASIO_DETAIL_POSIX_EVENT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include <pthread.h>
+#include "asio/detail/assert.hpp"
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class posix_event
+  : private noncopyable
+{
+public:
+  // Constructor.
+  ASIO_DECL posix_event();
+
+  // Destructor.
+  ~posix_event()
+  {
+    ::pthread_cond_destroy(&cond_);
+  }
+
+  // Signal the event. (Retained for backward compatibility.)
+  template <typename Lock>
+  void signal(Lock& lock)
+  {
+    this->signal_all(lock);
+  }
+
+  // Signal all waiters.
+  template <typename Lock>
+  void signal_all(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    (void)lock;
+    state_ |= 1;
+    ::pthread_cond_broadcast(&cond_); // Ignore EINVAL.
+  }
+
+  // Unlock the mutex and signal one waiter.
+  template <typename Lock>
+  void unlock_and_signal_one(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    state_ |= 1;
+    bool have_waiters = (state_ > 1);
+    lock.unlock();
+    if (have_waiters)
+      ::pthread_cond_signal(&cond_); // Ignore EINVAL.
+  }
+
+  // If there's a waiter, unlock the mutex and signal it.
+  template <typename Lock>
+  bool maybe_unlock_and_signal_one(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    state_ |= 1;
+    if (state_ > 1)
+    {
+      lock.unlock();
+      ::pthread_cond_signal(&cond_); // Ignore EINVAL.
+      return true;
+    }
+    return false;
+  }
+
+  // Reset the event.
+  template <typename Lock>
+  void clear(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    (void)lock;
+    state_ &= ~std::size_t(1);
+  }
+
+  // Wait for the event to become signalled.
+  template <typename Lock>
+  void wait(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    while ((state_ & 1) == 0)
+    {
+      state_ += 2;
+      ::pthread_cond_wait(&cond_, &lock.mutex().mutex_); // Ignore EINVAL.
+      state_ -= 2;
+    }
+  }
+
+  // Timed wait for the event to become signalled.
+  template <typename Lock>
+  bool wait_for_usec(Lock& lock, long usec)
+  {
+    ASIO_ASSERT(lock.locked());
+    if ((state_ & 1) == 0)
+    {
+      state_ += 2;
+      timespec ts;
+#if (defined(__MACH__) && defined(__APPLE__)) \
+      || (defined(__ANDROID__) && (__ANDROID_API__ < 21) \
+          && defined(HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE))
+      ts.tv_sec = usec / 1000000;
+      ts.tv_nsec = (usec % 1000000) * 1000;
+      ::pthread_cond_timedwait_relative_np(
+          &cond_, &lock.mutex().mutex_, &ts); // Ignore EINVAL.
+#else // (defined(__MACH__) && defined(__APPLE__))
+      // || (defined(__ANDROID__) && (__ANDROID_API__ < 21)
+      //     && defined(HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE))
+      if (::clock_gettime(CLOCK_MONOTONIC, &ts) == 0)
+      {
+        ts.tv_sec += usec / 1000000;
+        ts.tv_nsec = (usec % 1000000) * 1000;
+        ts.tv_sec += ts.tv_nsec / 1000000000;
+        ts.tv_nsec = ts.tv_nsec % 1000000000;
+        ::pthread_cond_timedwait(&cond_,
+            &lock.mutex().mutex_, &ts); // Ignore EINVAL.
+      }
+#endif // (defined(__MACH__) && defined(__APPLE__))
+       // || (defined(__ANDROID__) && (__ANDROID_API__ < 21)
+       //     && defined(HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE))
+      state_ -= 2;
+    }
+    return (state_ & 1) != 0;
+  }
+
+private:
+  ::pthread_cond_t cond_;
+  std::size_t state_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/posix_event.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_POSIX_EVENT_HPP
diff --git a/subprojects/asio/include/asio/detail/posix_fd_set_adapter.hpp b/subprojects/asio/include/asio/detail/posix_fd_set_adapter.hpp
new file mode 100644
index 000000000..95042d663
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_fd_set_adapter.hpp
@@ -0,0 +1,118 @@
+//
+// detail/posix_fd_set_adapter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_FD_SET_ADAPTER_HPP
+#define ASIO_DETAIL_POSIX_FD_SET_ADAPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(__CYGWIN__) \
+  && !defined(ASIO_WINDOWS_RUNTIME)
+
+#include <cstring>
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/reactor_op_queue.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Adapts the FD_SET type to meet the Descriptor_Set concept's requirements.
+class posix_fd_set_adapter : noncopyable
+{
+public:
+  posix_fd_set_adapter()
+    : max_descriptor_(invalid_socket)
+  {
+    using namespace std; // Needed for memset on Solaris.
+    FD_ZERO(&fd_set_);
+  }
+
+  void reset()
+  {
+    using namespace std; // Needed for memset on Solaris.
+    FD_ZERO(&fd_set_);
+  }
+
+  bool set(socket_type descriptor)
+  {
+    if (descriptor < (socket_type)FD_SETSIZE)
+    {
+      if (max_descriptor_ == invalid_socket || descriptor > max_descriptor_)
+        max_descriptor_ = descriptor;
+      FD_SET(descriptor, &fd_set_);
+      return true;
+    }
+    return false;
+  }
+
+  void set(reactor_op_queue<socket_type>& operations, op_queue<operation>& ops)
+  {
+    reactor_op_queue<socket_type>::iterator i = operations.begin();
+    while (i != operations.end())
+    {
+      reactor_op_queue<socket_type>::iterator op_iter = i++;
+      if (!set(op_iter->first))
+      {
+        asio::error_code ec(error::fd_set_failure);
+        operations.cancel_operations(op_iter, ops, ec);
+      }
+    }
+  }
+
+  bool is_set(socket_type descriptor) const
+  {
+    return FD_ISSET(descriptor, &fd_set_) != 0;
+  }
+
+  operator fd_set*()
+  {
+    return &fd_set_;
+  }
+
+  socket_type max_descriptor() const
+  {
+    return max_descriptor_;
+  }
+
+  void perform(reactor_op_queue<socket_type>& operations,
+      op_queue<operation>& ops) const
+  {
+    reactor_op_queue<socket_type>::iterator i = operations.begin();
+    while (i != operations.end())
+    {
+      reactor_op_queue<socket_type>::iterator op_iter = i++;
+      if (is_set(op_iter->first))
+        operations.perform_operations(op_iter, ops);
+    }
+  }
+
+private:
+  mutable fd_set fd_set_;
+  socket_type max_descriptor_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS)
+       // && !defined(__CYGWIN__)
+       // && !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_POSIX_FD_SET_ADAPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/posix_global.hpp b/subprojects/asio/include/asio/detail/posix_global.hpp
new file mode 100644
index 000000000..7ee0a7154
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_global.hpp
@@ -0,0 +1,80 @@
+//
+// detail/posix_global.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_GLOBAL_HPP
+#define ASIO_DETAIL_POSIX_GLOBAL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include <exception>
+#include <pthread.h>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+struct posix_global_impl
+{
+  // Helper function to perform initialisation.
+  static void do_init()
+  {
+    instance_.static_ptr_ = instance_.ptr_ = new T;
+  }
+
+  // Destructor automatically cleans up the global.
+  ~posix_global_impl()
+  {
+    delete static_ptr_;
+  }
+
+  static ::pthread_once_t init_once_;
+  static T* static_ptr_;
+  static posix_global_impl instance_;
+  T* ptr_;
+};
+
+template <typename T>
+::pthread_once_t posix_global_impl<T>::init_once_ = PTHREAD_ONCE_INIT;
+
+template <typename T>
+T* posix_global_impl<T>::static_ptr_ = 0;
+
+template <typename T>
+posix_global_impl<T> posix_global_impl<T>::instance_;
+
+template <typename T>
+T& posix_global()
+{
+  int result = ::pthread_once(
+      &posix_global_impl<T>::init_once_,
+      &posix_global_impl<T>::do_init);
+
+  if (result != 0)
+    std::terminate();
+
+  return *posix_global_impl<T>::instance_.ptr_;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_POSIX_GLOBAL_HPP
diff --git a/subprojects/asio/include/asio/detail/posix_mutex.hpp b/subprojects/asio/include/asio/detail/posix_mutex.hpp
new file mode 100644
index 000000000..c0d9fc9b7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_mutex.hpp
@@ -0,0 +1,76 @@
+//
+// detail/posix_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_MUTEX_HPP
+#define ASIO_DETAIL_POSIX_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include <pthread.h>
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class posix_event;
+
+class posix_mutex
+  : private noncopyable
+{
+public:
+  typedef asio::detail::scoped_lock<posix_mutex> scoped_lock;
+
+  // Constructor.
+  ASIO_DECL posix_mutex();
+
+  // Destructor.
+  ~posix_mutex()
+  {
+    ::pthread_mutex_destroy(&mutex_); // Ignore EBUSY.
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+    (void)::pthread_mutex_lock(&mutex_); // Ignore EINVAL.
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+    (void)::pthread_mutex_unlock(&mutex_); // Ignore EINVAL.
+  }
+
+private:
+  friend class posix_event;
+  ::pthread_mutex_t mutex_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/posix_mutex.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_POSIX_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/posix_signal_blocker.hpp b/subprojects/asio/include/asio/detail/posix_signal_blocker.hpp
new file mode 100644
index 000000000..fab5eb129
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_signal_blocker.hpp
@@ -0,0 +1,85 @@
+//
+// detail/posix_signal_blocker.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
+#define ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include <csignal>
+#include <pthread.h>
+#include <signal.h>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class posix_signal_blocker
+  : private noncopyable
+{
+public:
+  // Constructor blocks all signals for the calling thread.
+  posix_signal_blocker()
+    : blocked_(false)
+  {
+    sigset_t new_mask;
+    sigfillset(&new_mask);
+    blocked_ = (pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask_) == 0);
+  }
+
+  // Destructor restores the previous signal mask.
+  ~posix_signal_blocker()
+  {
+    if (blocked_)
+      pthread_sigmask(SIG_SETMASK, &old_mask_, 0);
+  }
+
+  // Block all signals for the calling thread.
+  void block()
+  {
+    if (!blocked_)
+    {
+      sigset_t new_mask;
+      sigfillset(&new_mask);
+      blocked_ = (pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask_) == 0);
+    }
+  }
+
+  // Restore the previous signal mask.
+  void unblock()
+  {
+    if (blocked_)
+      blocked_ = (pthread_sigmask(SIG_SETMASK, &old_mask_, 0) != 0);
+  }
+
+private:
+  // Have signals been blocked.
+  bool blocked_;
+
+  // The previous signal mask.
+  sigset_t old_mask_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_POSIX_SIGNAL_BLOCKER_HPP
diff --git a/subprojects/asio/include/asio/detail/posix_static_mutex.hpp b/subprojects/asio/include/asio/detail/posix_static_mutex.hpp
new file mode 100644
index 000000000..59b86c188
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_static_mutex.hpp
@@ -0,0 +1,64 @@
+//
+// detail/posix_static_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_STATIC_MUTEX_HPP
+#define ASIO_DETAIL_POSIX_STATIC_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include <pthread.h>
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct posix_static_mutex
+{
+  typedef asio::detail::scoped_lock<posix_static_mutex> scoped_lock;
+
+  // Initialise the mutex.
+  void init()
+  {
+    // Nothing to do.
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+    (void)::pthread_mutex_lock(&mutex_); // Ignore EINVAL.
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+    (void)::pthread_mutex_unlock(&mutex_); // Ignore EINVAL.
+  }
+
+  ::pthread_mutex_t mutex_;
+};
+
+#define ASIO_POSIX_STATIC_MUTEX_INIT { PTHREAD_MUTEX_INITIALIZER }
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_POSIX_STATIC_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/posix_thread.hpp b/subprojects/asio/include/asio/detail/posix_thread.hpp
new file mode 100644
index 000000000..1817af28d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_thread.hpp
@@ -0,0 +1,109 @@
+//
+// detail/posix_thread.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_THREAD_HPP
+#define ASIO_DETAIL_POSIX_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include <cstddef>
+#include <pthread.h>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+extern "C"
+{
+  ASIO_DECL void* asio_detail_posix_thread_function(void* arg);
+}
+
+class posix_thread
+  : private noncopyable
+{
+public:
+  // Constructor.
+  template <typename Function>
+  posix_thread(Function f, unsigned int = 0)
+    : joined_(false)
+  {
+    start_thread(new func<Function>(f));
+  }
+
+  // Destructor.
+  ASIO_DECL ~posix_thread();
+
+  // Wait for the thread to exit.
+  ASIO_DECL void join();
+
+  // Get number of CPUs.
+  ASIO_DECL static std::size_t hardware_concurrency();
+
+private:
+  friend void* asio_detail_posix_thread_function(void* arg);
+
+  class func_base
+  {
+  public:
+    virtual ~func_base() {}
+    virtual void run() = 0;
+  };
+
+  struct auto_func_base_ptr
+  {
+    func_base* ptr;
+    ~auto_func_base_ptr() { delete ptr; }
+  };
+
+  template <typename Function>
+  class func
+    : public func_base
+  {
+  public:
+    func(Function f)
+      : f_(f)
+    {
+    }
+
+    virtual void run()
+    {
+      f_();
+    }
+
+  private:
+    Function f_;
+  };
+
+  ASIO_DECL void start_thread(func_base* arg);
+
+  ::pthread_t thread_;
+  bool joined_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/posix_thread.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_POSIX_THREAD_HPP
diff --git a/subprojects/asio/include/asio/detail/posix_tss_ptr.hpp b/subprojects/asio/include/asio/detail/posix_tss_ptr.hpp
new file mode 100644
index 000000000..a3096b43e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/posix_tss_ptr.hpp
@@ -0,0 +1,79 @@
+//
+// detail/posix_tss_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_POSIX_TSS_PTR_HPP
+#define ASIO_DETAIL_POSIX_TSS_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_PTHREADS)
+
+#include <pthread.h>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper function to create thread-specific storage.
+ASIO_DECL void posix_tss_ptr_create(pthread_key_t& key);
+
+template <typename T>
+class posix_tss_ptr
+  : private noncopyable
+{
+public:
+  // Constructor.
+  posix_tss_ptr()
+  {
+    posix_tss_ptr_create(tss_key_);
+  }
+
+  // Destructor.
+  ~posix_tss_ptr()
+  {
+    ::pthread_key_delete(tss_key_);
+  }
+
+  // Get the value.
+  operator T*() const
+  {
+    return static_cast<T*>(::pthread_getspecific(tss_key_));
+  }
+
+  // Set the value.
+  void operator=(T* value)
+  {
+    ::pthread_setspecific(tss_key_, value);
+  }
+
+private:
+  // Thread-specific storage to allow unlocked access to determine whether a
+  // thread is a member of the pool.
+  pthread_key_t tss_key_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/posix_tss_ptr.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_PTHREADS)
+
+#endif // ASIO_DETAIL_POSIX_TSS_PTR_HPP
diff --git a/subprojects/asio/include/asio/detail/push_options.hpp b/subprojects/asio/include/asio/detail/push_options.hpp
new file mode 100644
index 000000000..0a3e97980
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/push_options.hpp
@@ -0,0 +1,175 @@
+//
+// detail/push_options.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+// No header guard
+
+#if defined(__COMO__)
+
+// Comeau C++
+
+#elif defined(__DMC__)
+
+// Digital Mars C++
+
+#elif defined(__INTEL_COMPILER) || defined(__ICL) \
+  || defined(__ICC) || defined(__ECC)
+
+// Intel C++
+
+# if (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+#  pragma GCC visibility push (default)
+# endif // (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+
+#elif defined(__clang__)
+
+// Clang
+
+# if defined(__OBJC__)
+#  if !defined(__APPLE_CC__) || (__APPLE_CC__ <= 1)
+#   if !defined(ASIO_DISABLE_OBJC_WORKAROUND)
+#    if !defined(Protocol) && !defined(id)
+#     define Protocol cpp_Protocol
+#     define id cpp_id
+#     define ASIO_OBJC_WORKAROUND
+#    endif
+#   endif
+#  endif
+# endif
+
+# if !defined(_WIN32) && !defined(__WIN32__) && !defined(WIN32)
+#  pragma GCC visibility push (default)
+# endif // !defined(_WIN32) && !defined(__WIN32__) && !defined(WIN32)
+
+#elif defined(__GNUC__)
+
+// GNU C++
+
+# if defined(__MINGW32__) || defined(__CYGWIN__)
+#  pragma pack (push, 8)
+# endif
+
+# if defined(__OBJC__)
+#  if !defined(__APPLE_CC__) || (__APPLE_CC__ <= 1)
+#   if !defined(ASIO_DISABLE_OBJC_WORKAROUND)
+#    if !defined(Protocol) && !defined(id)
+#     define Protocol cpp_Protocol
+#     define id cpp_id
+#     define ASIO_OBJC_WORKAROUND
+#    endif
+#   endif
+#  endif
+# endif
+
+# if (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+#  pragma GCC visibility push (default)
+# endif // (__GNUC__ == 4 && __GNUC_MINOR__ >= 1) || (__GNUC__ > 4)
+
+# if (__GNUC__ >= 7)
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+# endif // (__GNUC__ >= 7)
+
+#elif defined(__KCC)
+
+// Kai C++
+
+#elif defined(__sgi)
+
+// SGI MIPSpro C++
+
+#elif defined(__DECCXX)
+
+// Compaq Tru64 Unix cxx
+
+#elif defined(__ghs)
+
+// Greenhills C++
+
+#elif defined(__BORLANDC__)
+
+// Borland C++
+
+# pragma option push -a8 -b -Ve- -Vx- -w-inl -vi-
+# pragma nopushoptwarn
+# pragma nopackwarning
+# if !defined(__MT__)
+#  error Multithreaded RTL must be selected.
+# endif // !defined(__MT__)
+
+#elif defined(__MWERKS__)
+
+// Metrowerks CodeWarrior
+
+#elif defined(__SUNPRO_CC)
+
+// Sun Workshop Compiler C++
+
+#elif defined(__HP_aCC)
+
+// HP aCC
+
+#elif defined(__MRC__) || defined(__SC__)
+
+// MPW MrCpp or SCpp
+
+#elif defined(__IBMCPP__)
+
+// IBM Visual Age
+
+#elif defined(_MSC_VER)
+
+// Microsoft Visual C++
+//
+// Must remain the last #elif since some other vendors (Metrowerks, for example)
+// also #define _MSC_VER
+
+# pragma warning (disable:4103)
+# pragma warning (push)
+# pragma warning (disable:4127)
+# pragma warning (disable:4180)
+# pragma warning (disable:4244)
+# pragma warning (disable:4355)
+# pragma warning (disable:4510)
+# pragma warning (disable:4512)
+# pragma warning (disable:4610)
+# pragma warning (disable:4675)
+# if (_MSC_VER < 1600)
+// Visual Studio 2008 generates spurious warnings about unused parameters.
+#  pragma warning (disable:4100)
+# endif // (_MSC_VER < 1600)
+# if defined(_M_IX86) && defined(_Wp64)
+// The /Wp64 option is broken. If you want to check 64 bit portability, use a
+// 64 bit compiler!
+#  pragma warning (disable:4311)
+#  pragma warning (disable:4312)
+# endif // defined(_M_IX86) && defined(_Wp64)
+# pragma pack (push, 8)
+// Note that if the /Og optimisation flag is enabled with MSVC6, the compiler
+// has a tendency to incorrectly optimise away some calls to member template
+// functions, even though those functions contain code that should not be
+// optimised away! Therefore we will always disable this optimisation option
+// for the MSVC6 compiler.
+# if (_MSC_VER < 1300)
+#  pragma optimize ("g", off)
+# endif
+# if !defined(_MT)
+#  error Multithreaded RTL must be selected.
+# endif // !defined(_MT)
+
+# if defined(__cplusplus_cli) || defined(__cplusplus_winrt)
+#  if !defined(ASIO_DISABLE_CLR_WORKAROUND)
+#   if !defined(generic)
+#    define generic cpp_generic
+#    define ASIO_CLR_WORKAROUND
+#   endif
+#  endif
+# endif
+
+#endif
diff --git a/subprojects/asio/include/asio/detail/reactive_descriptor_service.hpp b/subprojects/asio/include/asio/detail/reactive_descriptor_service.hpp
new file mode 100644
index 000000000..e86686399
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_descriptor_service.hpp
@@ -0,0 +1,388 @@
+//
+// detail/reactive_descriptor_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_DESCRIPTOR_SERVICE_HPP
+#define ASIO_DETAIL_REACTIVE_DESCRIPTOR_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+
+#include "asio/buffer.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/descriptor_ops.hpp"
+#include "asio/detail/descriptor_read_op.hpp"
+#include "asio/detail/descriptor_write_op.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/reactive_null_buffers_op.hpp"
+#include "asio/detail/reactive_wait_op.hpp"
+#include "asio/detail/reactor.hpp"
+#include "asio/posix/descriptor_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class reactive_descriptor_service :
+  public service_base<reactive_descriptor_service>
+{
+public:
+  // The native type of a descriptor.
+  typedef int native_handle_type;
+
+  // The implementation type of the descriptor.
+  class implementation_type
+    : private asio::detail::noncopyable
+  {
+  public:
+    // Default constructor.
+    implementation_type()
+      : descriptor_(-1),
+        state_(0)
+    {
+    }
+
+  private:
+    // Only this service will have access to the internal values.
+    friend class reactive_descriptor_service;
+
+    // The native descriptor representation.
+    int descriptor_;
+
+    // The current state of the descriptor.
+    descriptor_ops::state_type state_;
+
+    // Per-descriptor data used by the reactor.
+    reactor::per_descriptor_data reactor_data_;
+  };
+
+  // Constructor.
+  ASIO_DECL reactive_descriptor_service(
+      asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Construct a new descriptor implementation.
+  ASIO_DECL void construct(implementation_type& impl);
+
+  // Move-construct a new descriptor implementation.
+  ASIO_DECL void move_construct(implementation_type& impl,
+      implementation_type& other_impl);
+
+  // Move-assign from another descriptor implementation.
+  ASIO_DECL void move_assign(implementation_type& impl,
+      reactive_descriptor_service& other_service,
+      implementation_type& other_impl);
+
+  // Destroy a descriptor implementation.
+  ASIO_DECL void destroy(implementation_type& impl);
+
+  // Assign a native descriptor to a descriptor implementation.
+  ASIO_DECL asio::error_code assign(implementation_type& impl,
+      const native_handle_type& native_descriptor,
+      asio::error_code& ec);
+
+  // Determine whether the descriptor is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return impl.descriptor_ != -1;
+  }
+
+  // Destroy a descriptor implementation.
+  ASIO_DECL asio::error_code close(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Get the native descriptor representation.
+  native_handle_type native_handle(const implementation_type& impl) const
+  {
+    return impl.descriptor_;
+  }
+
+  // Release ownership of the native descriptor representation.
+  ASIO_DECL native_handle_type release(implementation_type& impl);
+
+  // Cancel all operations associated with the descriptor.
+  ASIO_DECL asio::error_code cancel(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Perform an IO control command on the descriptor.
+  template <typename IO_Control_Command>
+  asio::error_code io_control(implementation_type& impl,
+      IO_Control_Command& command, asio::error_code& ec)
+  {
+    descriptor_ops::ioctl(impl.descriptor_, impl.state_,
+        command.name(), static_cast<ioctl_arg_type*>(command.data()), ec);
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the descriptor.
+  bool non_blocking(const implementation_type& impl) const
+  {
+    return (impl.state_ & descriptor_ops::user_set_non_blocking) != 0;
+  }
+
+  // Sets the non-blocking mode of the descriptor.
+  asio::error_code non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    descriptor_ops::set_user_non_blocking(
+        impl.descriptor_, impl.state_, mode, ec);
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the native descriptor implementation.
+  bool native_non_blocking(const implementation_type& impl) const
+  {
+    return (impl.state_ & descriptor_ops::internal_non_blocking) != 0;
+  }
+
+  // Sets the non-blocking mode of the native descriptor implementation.
+  asio::error_code native_non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    descriptor_ops::set_internal_non_blocking(
+        impl.descriptor_, impl.state_, mode, ec);
+    return ec;
+  }
+
+  // Wait for the descriptor to become ready to read, ready to write, or to have
+  // pending error conditions.
+  asio::error_code wait(implementation_type& impl,
+      posix::descriptor_base::wait_type w, asio::error_code& ec)
+  {
+    switch (w)
+    {
+    case posix::descriptor_base::wait_read:
+      descriptor_ops::poll_read(impl.descriptor_, impl.state_, ec);
+      break;
+    case posix::descriptor_base::wait_write:
+      descriptor_ops::poll_write(impl.descriptor_, impl.state_, ec);
+      break;
+    case posix::descriptor_base::wait_error:
+      descriptor_ops::poll_error(impl.descriptor_, impl.state_, ec);
+      break;
+    default:
+      ec = asio::error::invalid_argument;
+      break;
+    }
+
+    return ec;
+  }
+
+  // Asynchronously wait for the descriptor to become ready to read, ready to
+  // write, or to have pending error conditions.
+  template <typename Handler>
+  void async_wait(implementation_type& impl,
+      posix::descriptor_base::wait_type w, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_wait_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "descriptor",
+          &impl, impl.descriptor_, "async_wait"));
+
+    int op_type;
+    switch (w)
+    {
+    case posix::descriptor_base::wait_read:
+        op_type = reactor::read_op;
+        break;
+    case posix::descriptor_base::wait_write:
+        op_type = reactor::write_op;
+        break;
+    case posix::descriptor_base::wait_error:
+        op_type = reactor::except_op;
+        break;
+      default:
+        p.p->ec_ = asio::error::invalid_argument;
+        reactor_.post_immediate_completion(p.p, is_continuation);
+        p.v = p.p = 0;
+        return;
+    }
+
+    start_op(impl, op_type, p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+  // Write some data to the descriptor.
+  template <typename ConstBufferSequence>
+  size_t write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(buffers);
+
+    return descriptor_ops::sync_write(impl.descriptor_, impl.state_,
+        bufs.buffers(), bufs.count(), bufs.all_empty(), ec);
+  }
+
+  // Wait until data can be written without blocking.
+  size_t write_some(implementation_type& impl,
+      const null_buffers&, asio::error_code& ec)
+  {
+    // Wait for descriptor to become ready.
+    descriptor_ops::poll_write(impl.descriptor_, impl.state_, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous write. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef descriptor_write_op<ConstBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.descriptor_, buffers, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "descriptor",
+          &impl, impl.descriptor_, "async_write_some"));
+
+    start_op(impl, reactor::write_op, p.p, is_continuation, true,
+        buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::all_empty(buffers));
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous wait until data can be written without blocking.
+  template <typename Handler>
+  void async_write_some(implementation_type& impl,
+      const null_buffers&, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "descriptor",
+          &impl, impl.descriptor_, "async_write_some(null_buffers)"));
+
+    start_op(impl, reactor::write_op, p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+  // Read some data from the stream. Returns the number of bytes read.
+  template <typename MutableBufferSequence>
+  size_t read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    return descriptor_ops::sync_read(impl.descriptor_, impl.state_,
+        bufs.buffers(), bufs.count(), bufs.all_empty(), ec);
+  }
+
+  // Wait until data can be read without blocking.
+  size_t read_some(implementation_type& impl,
+      const null_buffers&, asio::error_code& ec)
+  {
+    // Wait for descriptor to become ready.
+    descriptor_ops::poll_read(impl.descriptor_, impl.state_, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous read. The buffer for the data being read must be
+  // valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef descriptor_read_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.descriptor_, buffers, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "descriptor",
+          &impl, impl.descriptor_, "async_read_some"));
+
+    start_op(impl, reactor::read_op, p.p, is_continuation, true,
+        buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::all_empty(buffers));
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be read without blocking.
+  template <typename Handler>
+  void async_read_some(implementation_type& impl,
+      const null_buffers&, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "descriptor",
+          &impl, impl.descriptor_, "async_read_some(null_buffers)"));
+
+    start_op(impl, reactor::read_op, p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+private:
+  // Start the asynchronous operation.
+  ASIO_DECL void start_op(implementation_type& impl, int op_type,
+      reactor_op* op, bool is_continuation, bool is_non_blocking, bool noop);
+
+  // The selector that performs event demultiplexing for the service.
+  reactor& reactor_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/reactive_descriptor_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_REACTIVE_DESCRIPTOR_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_null_buffers_op.hpp b/subprojects/asio/include/asio/detail/reactive_null_buffers_op.hpp
new file mode 100644
index 000000000..740826928
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_null_buffers_op.hpp
@@ -0,0 +1,90 @@
+//
+// detail/reactive_null_buffers_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_NULL_BUFFERS_OP_HPP
+#define ASIO_DETAIL_REACTIVE_NULL_BUFFERS_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class reactive_null_buffers_op : public reactor_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_null_buffers_op);
+
+  reactive_null_buffers_op(Handler& handler)
+    : reactor_op(&reactive_null_buffers_op::do_perform,
+        &reactive_null_buffers_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static status do_perform(reactor_op*)
+  {
+    return done;
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_null_buffers_op* o(static_cast<reactive_null_buffers_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_NULL_BUFFERS_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_serial_port_service.hpp b/subprojects/asio/include/asio/detail/reactive_serial_port_service.hpp
new file mode 100644
index 000000000..6fddd9f1a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_serial_port_service.hpp
@@ -0,0 +1,236 @@
+//
+// detail/reactive_serial_port_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SERIAL_PORT_SERVICE_HPP
+#define ASIO_DETAIL_REACTIVE_SERIAL_PORT_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_SERIAL_PORT)
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include <string>
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/serial_port_base.hpp"
+#include "asio/detail/descriptor_ops.hpp"
+#include "asio/detail/reactive_descriptor_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Extend reactive_descriptor_service to provide serial port support.
+class reactive_serial_port_service :
+  public service_base<reactive_serial_port_service>
+{
+public:
+  // The native type of a serial port.
+  typedef reactive_descriptor_service::native_handle_type native_handle_type;
+
+  // The implementation type of the serial port.
+  typedef reactive_descriptor_service::implementation_type implementation_type;
+
+  ASIO_DECL reactive_serial_port_service(
+      asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Construct a new serial port implementation.
+  void construct(implementation_type& impl)
+  {
+    descriptor_service_.construct(impl);
+  }
+
+  // Move-construct a new serial port implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    descriptor_service_.move_construct(impl, other_impl);
+  }
+
+  // Move-assign from another serial port implementation.
+  void move_assign(implementation_type& impl,
+      reactive_serial_port_service& other_service,
+      implementation_type& other_impl)
+  {
+    descriptor_service_.move_assign(impl,
+        other_service.descriptor_service_, other_impl);
+  }
+
+  // Destroy a serial port implementation.
+  void destroy(implementation_type& impl)
+  {
+    descriptor_service_.destroy(impl);
+  }
+
+  // Open the serial port using the specified device name.
+  ASIO_DECL asio::error_code open(implementation_type& impl,
+      const std::string& device, asio::error_code& ec);
+
+  // Assign a native descriptor to a serial port implementation.
+  asio::error_code assign(implementation_type& impl,
+      const native_handle_type& native_descriptor,
+      asio::error_code& ec)
+  {
+    return descriptor_service_.assign(impl, native_descriptor, ec);
+  }
+
+  // Determine whether the serial port is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return descriptor_service_.is_open(impl);
+  }
+
+  // Destroy a serial port implementation.
+  asio::error_code close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return descriptor_service_.close(impl, ec);
+  }
+
+  // Get the native serial port representation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return descriptor_service_.native_handle(impl);
+  }
+
+  // Cancel all operations associated with the serial port.
+  asio::error_code cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return descriptor_service_.cancel(impl, ec);
+  }
+
+  // Set an option on the serial port.
+  template <typename SettableSerialPortOption>
+  asio::error_code set_option(implementation_type& impl,
+      const SettableSerialPortOption& option, asio::error_code& ec)
+  {
+    return do_set_option(impl,
+        &reactive_serial_port_service::store_option<SettableSerialPortOption>,
+        &option, ec);
+  }
+
+  // Get an option from the serial port.
+  template <typename GettableSerialPortOption>
+  asio::error_code get_option(const implementation_type& impl,
+      GettableSerialPortOption& option, asio::error_code& ec) const
+  {
+    return do_get_option(impl,
+        &reactive_serial_port_service::load_option<GettableSerialPortOption>,
+        &option, ec);
+  }
+
+  // Send a break sequence to the serial port.
+  asio::error_code send_break(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    errno = 0;
+    descriptor_ops::error_wrapper(::tcsendbreak(
+          descriptor_service_.native_handle(impl), 0), ec);
+    return ec;
+  }
+
+  // Write the given data. Returns the number of bytes sent.
+  template <typename ConstBufferSequence>
+  size_t write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return descriptor_service_.write_some(impl, buffers, ec);
+  }
+
+  // Start an asynchronous write. The data being written must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, Handler& handler)
+  {
+    descriptor_service_.async_write_some(impl, buffers, handler);
+  }
+
+  // Read some data. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  size_t read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return descriptor_service_.read_some(impl, buffers, ec);
+  }
+
+  // Start an asynchronous read. The buffer for the data being received must be
+  // valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, Handler& handler)
+  {
+    descriptor_service_.async_read_some(impl, buffers, handler);
+  }
+
+private:
+  // Function pointer type for storing a serial port option.
+  typedef asio::error_code (*store_function_type)(
+      const void*, termios&, asio::error_code&);
+
+  // Helper function template to store a serial port option.
+  template <typename SettableSerialPortOption>
+  static asio::error_code store_option(const void* option,
+      termios& storage, asio::error_code& ec)
+  {
+    static_cast<const SettableSerialPortOption*>(option)->store(storage, ec);
+    return ec;
+  }
+
+  // Helper function to set a serial port option.
+  ASIO_DECL asio::error_code do_set_option(
+      implementation_type& impl, store_function_type store,
+      const void* option, asio::error_code& ec);
+
+  // Function pointer type for loading a serial port option.
+  typedef asio::error_code (*load_function_type)(
+      void*, const termios&, asio::error_code&);
+
+  // Helper function template to load a serial port option.
+  template <typename GettableSerialPortOption>
+  static asio::error_code load_option(void* option,
+      const termios& storage, asio::error_code& ec)
+  {
+    static_cast<GettableSerialPortOption*>(option)->load(storage, ec);
+    return ec;
+  }
+
+  // Helper function to get a serial port option.
+  ASIO_DECL asio::error_code do_get_option(
+      const implementation_type& impl, load_function_type load,
+      void* option, asio::error_code& ec) const;
+
+  // The implementation used for initiating asynchronous operations.
+  reactive_descriptor_service descriptor_service_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/reactive_serial_port_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+#endif // defined(ASIO_HAS_SERIAL_PORT)
+
+#endif // ASIO_DETAIL_REACTIVE_SERIAL_PORT_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_accept_op.hpp b/subprojects/asio/include/asio/detail/reactive_socket_accept_op.hpp
new file mode 100644
index 000000000..4a98f047f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_accept_op.hpp
@@ -0,0 +1,217 @@
+//
+// detail/reactive_socket_accept_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_ACCEPT_OP_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_ACCEPT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_holder.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Socket, typename Protocol>
+class reactive_socket_accept_op_base : public reactor_op
+{
+public:
+  reactive_socket_accept_op_base(socket_type socket,
+      socket_ops::state_type state, Socket& peer, const Protocol& protocol,
+      typename Protocol::endpoint* peer_endpoint, func_type complete_func)
+    : reactor_op(&reactive_socket_accept_op_base::do_perform, complete_func),
+      socket_(socket),
+      state_(state),
+      peer_(peer),
+      protocol_(protocol),
+      peer_endpoint_(peer_endpoint),
+      addrlen_(peer_endpoint ? peer_endpoint->capacity() : 0)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    reactive_socket_accept_op_base* o(
+        static_cast<reactive_socket_accept_op_base*>(base));
+
+    socket_type new_socket = invalid_socket;
+    status result = socket_ops::non_blocking_accept(o->socket_,
+        o->state_, o->peer_endpoint_ ? o->peer_endpoint_->data() : 0,
+        o->peer_endpoint_ ? &o->addrlen_ : 0, o->ec_, new_socket)
+    ? done : not_done;
+    o->new_socket_.reset(new_socket);
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_accept", o->ec_));
+
+    return result;
+  }
+
+  void do_assign()
+  {
+    if (new_socket_.get() != invalid_socket)
+    {
+      if (peer_endpoint_)
+        peer_endpoint_->resize(addrlen_);
+      peer_.assign(protocol_, new_socket_.get(), ec_);
+      if (!ec_)
+        new_socket_.release();
+    }
+  }
+
+private:
+  socket_type socket_;
+  socket_ops::state_type state_;
+  socket_holder new_socket_;
+  Socket& peer_;
+  Protocol protocol_;
+  typename Protocol::endpoint* peer_endpoint_;
+  std::size_t addrlen_;
+};
+
+template <typename Socket, typename Protocol, typename Handler>
+class reactive_socket_accept_op :
+  public reactive_socket_accept_op_base<Socket, Protocol>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_accept_op);
+
+  reactive_socket_accept_op(socket_type socket,
+      socket_ops::state_type state, Socket& peer, const Protocol& protocol,
+      typename Protocol::endpoint* peer_endpoint, Handler& handler)
+    : reactive_socket_accept_op_base<Socket, Protocol>(socket, state, peer,
+        protocol, peer_endpoint, &reactive_socket_accept_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_accept_op* o(static_cast<reactive_socket_accept_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    // On success, assign new connection to peer socket object.
+    if (owner)
+      o->do_assign();
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(o->handler_, o->ec_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+#if defined(ASIO_HAS_MOVE)
+
+template <typename Protocol, typename Handler>
+class reactive_socket_move_accept_op :
+  private Protocol::socket,
+  public reactive_socket_accept_op_base<typename Protocol::socket, Protocol>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_move_accept_op);
+
+  reactive_socket_move_accept_op(io_context& ioc, socket_type socket,
+      socket_ops::state_type state, const Protocol& protocol,
+      typename Protocol::endpoint* peer_endpoint, Handler& handler)
+    : Protocol::socket(ioc),
+      reactive_socket_accept_op_base<typename Protocol::socket, Protocol>(
+        socket, state, *this, protocol, peer_endpoint,
+        &reactive_socket_move_accept_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_move_accept_op* o(
+        static_cast<reactive_socket_move_accept_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    // On success, assign new connection to peer socket object.
+    if (owner)
+      o->do_assign();
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::move_binder2<Handler,
+      asio::error_code, typename Protocol::socket>
+        handler(0, ASIO_MOVE_CAST(Handler)(o->handler_), o->ec_,
+          ASIO_MOVE_CAST(typename Protocol::socket)(*o));
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+#endif // defined(ASIO_HAS_MOVE)
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_ACCEPT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_connect_op.hpp b/subprojects/asio/include/asio/detail/reactive_socket_connect_op.hpp
new file mode 100644
index 000000000..76164b2a8
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_connect_op.hpp
@@ -0,0 +1,113 @@
+//
+// detail/reactive_socket_connect_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_CONNECT_OP_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_CONNECT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class reactive_socket_connect_op_base : public reactor_op
+{
+public:
+  reactive_socket_connect_op_base(socket_type socket, func_type complete_func)
+    : reactor_op(&reactive_socket_connect_op_base::do_perform, complete_func),
+      socket_(socket)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    reactive_socket_connect_op_base* o(
+        static_cast<reactive_socket_connect_op_base*>(base));
+
+    status result = socket_ops::non_blocking_connect(
+        o->socket_, o->ec_) ? done : not_done;
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_connect", o->ec_));
+
+    return result;
+  }
+
+private:
+  socket_type socket_;
+};
+
+template <typename Handler>
+class reactive_socket_connect_op : public reactive_socket_connect_op_base
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_connect_op);
+
+  reactive_socket_connect_op(socket_type socket, Handler& handler)
+    : reactive_socket_connect_op_base(socket,
+        &reactive_socket_connect_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_connect_op* o
+      (static_cast<reactive_socket_connect_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(o->handler_, o->ec_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_CONNECT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_recv_op.hpp b/subprojects/asio/include/asio/detail/reactive_socket_recv_op.hpp
new file mode 100644
index 000000000..04bd266f9
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_recv_op.hpp
@@ -0,0 +1,135 @@
+//
+// detail/reactive_socket_recv_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_RECV_OP_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_RECV_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence>
+class reactive_socket_recv_op_base : public reactor_op
+{
+public:
+  reactive_socket_recv_op_base(socket_type socket,
+      socket_ops::state_type state, const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, func_type complete_func)
+    : reactor_op(&reactive_socket_recv_op_base::do_perform, complete_func),
+      socket_(socket),
+      state_(state),
+      buffers_(buffers),
+      flags_(flags)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    reactive_socket_recv_op_base* o(
+        static_cast<reactive_socket_recv_op_base*>(base));
+
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(o->buffers_);
+
+    status result = socket_ops::non_blocking_recv(o->socket_,
+        bufs.buffers(), bufs.count(), o->flags_,
+        (o->state_ & socket_ops::stream_oriented) != 0,
+        o->ec_, o->bytes_transferred_) ? done : not_done;
+
+    if (result == done)
+      if ((o->state_ & socket_ops::stream_oriented) != 0)
+        if (o->bytes_transferred_ == 0)
+          result = done_and_exhausted;
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_recv",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  socket_type socket_;
+  socket_ops::state_type state_;
+  MutableBufferSequence buffers_;
+  socket_base::message_flags flags_;
+};
+
+template <typename MutableBufferSequence, typename Handler>
+class reactive_socket_recv_op :
+  public reactive_socket_recv_op_base<MutableBufferSequence>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_recv_op);
+
+  reactive_socket_recv_op(socket_type socket,
+      socket_ops::state_type state, const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+    : reactive_socket_recv_op_base<MutableBufferSequence>(socket, state,
+        buffers, flags, &reactive_socket_recv_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_recv_op* o(static_cast<reactive_socket_recv_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_RECV_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_recvfrom_op.hpp b/subprojects/asio/include/asio/detail/reactive_socket_recvfrom_op.hpp
new file mode 100644
index 000000000..3d4fa4cad
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_recvfrom_op.hpp
@@ -0,0 +1,138 @@
+//
+// detail/reactive_socket_recvfrom_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_RECVFROM_OP_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_RECVFROM_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence, typename Endpoint>
+class reactive_socket_recvfrom_op_base : public reactor_op
+{
+public:
+  reactive_socket_recvfrom_op_base(socket_type socket, int protocol_type,
+      const MutableBufferSequence& buffers, Endpoint& endpoint,
+      socket_base::message_flags flags, func_type complete_func)
+    : reactor_op(&reactive_socket_recvfrom_op_base::do_perform, complete_func),
+      socket_(socket),
+      protocol_type_(protocol_type),
+      buffers_(buffers),
+      sender_endpoint_(endpoint),
+      flags_(flags)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    reactive_socket_recvfrom_op_base* o(
+        static_cast<reactive_socket_recvfrom_op_base*>(base));
+
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(o->buffers_);
+
+    std::size_t addr_len = o->sender_endpoint_.capacity();
+    status result = socket_ops::non_blocking_recvfrom(o->socket_,
+        bufs.buffers(), bufs.count(), o->flags_,
+        o->sender_endpoint_.data(), &addr_len,
+        o->ec_, o->bytes_transferred_) ? done : not_done;
+
+    if (result && !o->ec_)
+      o->sender_endpoint_.resize(addr_len);
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_recvfrom",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  socket_type socket_;
+  int protocol_type_;
+  MutableBufferSequence buffers_;
+  Endpoint& sender_endpoint_;
+  socket_base::message_flags flags_;
+};
+
+template <typename MutableBufferSequence, typename Endpoint, typename Handler>
+class reactive_socket_recvfrom_op :
+  public reactive_socket_recvfrom_op_base<MutableBufferSequence, Endpoint>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_recvfrom_op);
+
+  reactive_socket_recvfrom_op(socket_type socket, int protocol_type,
+      const MutableBufferSequence& buffers, Endpoint& endpoint,
+      socket_base::message_flags flags, Handler& handler)
+    : reactive_socket_recvfrom_op_base<MutableBufferSequence, Endpoint>(
+        socket, protocol_type, buffers, endpoint, flags,
+        &reactive_socket_recvfrom_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_recvfrom_op* o(
+        static_cast<reactive_socket_recvfrom_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_RECVFROM_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_recvmsg_op.hpp b/subprojects/asio/include/asio/detail/reactive_socket_recvmsg_op.hpp
new file mode 100644
index 000000000..f47327472
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_recvmsg_op.hpp
@@ -0,0 +1,132 @@
+//
+// detail/reactive_socket_recvmsg_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_RECVMSG_OP_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_RECVMSG_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/socket_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence>
+class reactive_socket_recvmsg_op_base : public reactor_op
+{
+public:
+  reactive_socket_recvmsg_op_base(socket_type socket,
+      const MutableBufferSequence& buffers, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, func_type complete_func)
+    : reactor_op(&reactive_socket_recvmsg_op_base::do_perform, complete_func),
+      socket_(socket),
+      buffers_(buffers),
+      in_flags_(in_flags),
+      out_flags_(out_flags)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    reactive_socket_recvmsg_op_base* o(
+        static_cast<reactive_socket_recvmsg_op_base*>(base));
+
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(o->buffers_);
+
+    status result = socket_ops::non_blocking_recvmsg(o->socket_,
+        bufs.buffers(), bufs.count(),
+        o->in_flags_, o->out_flags_,
+        o->ec_, o->bytes_transferred_) ? done : not_done;
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_recvmsg",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  socket_type socket_;
+  MutableBufferSequence buffers_;
+  socket_base::message_flags in_flags_;
+  socket_base::message_flags& out_flags_;
+};
+
+template <typename MutableBufferSequence, typename Handler>
+class reactive_socket_recvmsg_op :
+  public reactive_socket_recvmsg_op_base<MutableBufferSequence>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_recvmsg_op);
+
+  reactive_socket_recvmsg_op(socket_type socket,
+      const MutableBufferSequence& buffers, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, Handler& handler)
+    : reactive_socket_recvmsg_op_base<MutableBufferSequence>(socket, buffers,
+        in_flags, out_flags, &reactive_socket_recvmsg_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_recvmsg_op* o(
+        static_cast<reactive_socket_recvmsg_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_RECVMSG_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_send_op.hpp b/subprojects/asio/include/asio/detail/reactive_socket_send_op.hpp
new file mode 100644
index 000000000..bd550d9c5
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_send_op.hpp
@@ -0,0 +1,134 @@
+//
+// detail/reactive_socket_send_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_SEND_OP_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_SEND_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename ConstBufferSequence>
+class reactive_socket_send_op_base : public reactor_op
+{
+public:
+  reactive_socket_send_op_base(socket_type socket,
+      socket_ops::state_type state, const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, func_type complete_func)
+    : reactor_op(&reactive_socket_send_op_base::do_perform, complete_func),
+      socket_(socket),
+      state_(state),
+      buffers_(buffers),
+      flags_(flags)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    reactive_socket_send_op_base* o(
+        static_cast<reactive_socket_send_op_base*>(base));
+
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(o->buffers_);
+
+    status result = socket_ops::non_blocking_send(o->socket_,
+          bufs.buffers(), bufs.count(), o->flags_,
+          o->ec_, o->bytes_transferred_) ? done : not_done;
+
+    if (result == done)
+      if ((o->state_ & socket_ops::stream_oriented) != 0)
+        if (o->bytes_transferred_ < bufs.total_size())
+          result = done_and_exhausted;
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_send",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  socket_type socket_;
+  socket_ops::state_type state_;
+  ConstBufferSequence buffers_;
+  socket_base::message_flags flags_;
+};
+
+template <typename ConstBufferSequence, typename Handler>
+class reactive_socket_send_op :
+  public reactive_socket_send_op_base<ConstBufferSequence>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_send_op);
+
+  reactive_socket_send_op(socket_type socket,
+      socket_ops::state_type state, const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+    : reactive_socket_send_op_base<ConstBufferSequence>(socket,
+        state, buffers, flags, &reactive_socket_send_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_send_op* o(static_cast<reactive_socket_send_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_SEND_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_sendto_op.hpp b/subprojects/asio/include/asio/detail/reactive_socket_sendto_op.hpp
new file mode 100644
index 000000000..c97554d7b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_sendto_op.hpp
@@ -0,0 +1,130 @@
+//
+// detail/reactive_socket_sendto_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_SENDTO_OP_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_SENDTO_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename ConstBufferSequence, typename Endpoint>
+class reactive_socket_sendto_op_base : public reactor_op
+{
+public:
+  reactive_socket_sendto_op_base(socket_type socket,
+      const ConstBufferSequence& buffers, const Endpoint& endpoint,
+      socket_base::message_flags flags, func_type complete_func)
+    : reactor_op(&reactive_socket_sendto_op_base::do_perform, complete_func),
+      socket_(socket),
+      buffers_(buffers),
+      destination_(endpoint),
+      flags_(flags)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    reactive_socket_sendto_op_base* o(
+        static_cast<reactive_socket_sendto_op_base*>(base));
+
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(o->buffers_);
+
+    status result = socket_ops::non_blocking_sendto(o->socket_,
+          bufs.buffers(), bufs.count(), o->flags_,
+          o->destination_.data(), o->destination_.size(),
+          o->ec_, o->bytes_transferred_) ? done : not_done;
+
+    ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_sendto",
+          o->ec_, o->bytes_transferred_));
+
+    return result;
+  }
+
+private:
+  socket_type socket_;
+  ConstBufferSequence buffers_;
+  Endpoint destination_;
+  socket_base::message_flags flags_;
+};
+
+template <typename ConstBufferSequence, typename Endpoint, typename Handler>
+class reactive_socket_sendto_op :
+  public reactive_socket_sendto_op_base<ConstBufferSequence, Endpoint>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_socket_sendto_op);
+
+  reactive_socket_sendto_op(socket_type socket,
+      const ConstBufferSequence& buffers, const Endpoint& endpoint,
+      socket_base::message_flags flags, Handler& handler)
+    : reactive_socket_sendto_op_base<ConstBufferSequence, Endpoint>(socket,
+        buffers, endpoint, flags, &reactive_socket_sendto_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_socket_sendto_op* o(static_cast<reactive_socket_sendto_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->bytes_transferred_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_SENDTO_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_service.hpp b/subprojects/asio/include/asio/detail/reactive_socket_service.hpp
new file mode 100644
index 000000000..15a4fdb58
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_service.hpp
@@ -0,0 +1,526 @@
+//
+// detail/reactive_socket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_IOCP)
+
+#include "asio/buffer.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/socket_base.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/reactive_null_buffers_op.hpp"
+#include "asio/detail/reactive_socket_accept_op.hpp"
+#include "asio/detail/reactive_socket_connect_op.hpp"
+#include "asio/detail/reactive_socket_recvfrom_op.hpp"
+#include "asio/detail/reactive_socket_sendto_op.hpp"
+#include "asio/detail/reactive_socket_service_base.hpp"
+#include "asio/detail/reactor.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_holder.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol>
+class reactive_socket_service :
+  public service_base<reactive_socket_service<Protocol> >,
+  public reactive_socket_service_base
+{
+public:
+  // The protocol type.
+  typedef Protocol protocol_type;
+
+  // The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  // The native type of a socket.
+  typedef socket_type native_handle_type;
+
+  // The implementation type of the socket.
+  struct implementation_type :
+    reactive_socket_service_base::base_implementation_type
+  {
+    // Default constructor.
+    implementation_type()
+      : protocol_(endpoint_type().protocol())
+    {
+    }
+
+    // The protocol associated with the socket.
+    protocol_type protocol_;
+  };
+
+  // Constructor.
+  reactive_socket_service(asio::io_context& io_context)
+    : service_base<reactive_socket_service<Protocol> >(io_context),
+      reactive_socket_service_base(io_context)
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    this->base_shutdown();
+  }
+
+  // Move-construct a new socket implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    this->base_move_construct(impl, other_impl);
+
+    impl.protocol_ = other_impl.protocol_;
+    other_impl.protocol_ = endpoint_type().protocol();
+  }
+
+  // Move-assign from another socket implementation.
+  void move_assign(implementation_type& impl,
+      reactive_socket_service_base& other_service,
+      implementation_type& other_impl)
+  {
+    this->base_move_assign(impl, other_service, other_impl);
+
+    impl.protocol_ = other_impl.protocol_;
+    other_impl.protocol_ = endpoint_type().protocol();
+  }
+
+  // Move-construct a new socket implementation from another protocol type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      reactive_socket_service<Protocol1>&,
+      typename reactive_socket_service<
+        Protocol1>::implementation_type& other_impl)
+  {
+    this->base_move_construct(impl, other_impl);
+
+    impl.protocol_ = protocol_type(other_impl.protocol_);
+    other_impl.protocol_ = typename Protocol1::endpoint().protocol();
+  }
+
+  // Open a new socket implementation.
+  asio::error_code open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    if (!do_open(impl, protocol.family(),
+          protocol.type(), protocol.protocol(), ec))
+      impl.protocol_ = protocol;
+    return ec;
+  }
+
+  // Assign a native socket to a socket implementation.
+  asio::error_code assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_socket,
+      asio::error_code& ec)
+  {
+    if (!do_assign(impl, protocol.type(), native_socket, ec))
+      impl.protocol_ = protocol;
+    return ec;
+  }
+
+  // Get the native socket representation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return impl.socket_;
+  }
+
+  // Bind the socket to the specified local endpoint.
+  asio::error_code bind(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    socket_ops::bind(impl.socket_, endpoint.data(), endpoint.size(), ec);
+    return ec;
+  }
+
+  // Set a socket option.
+  template <typename Option>
+  asio::error_code set_option(implementation_type& impl,
+      const Option& option, asio::error_code& ec)
+  {
+    socket_ops::setsockopt(impl.socket_, impl.state_,
+        option.level(impl.protocol_), option.name(impl.protocol_),
+        option.data(impl.protocol_), option.size(impl.protocol_), ec);
+    return ec;
+  }
+
+  // Set a socket option.
+  template <typename Option>
+  asio::error_code get_option(const implementation_type& impl,
+      Option& option, asio::error_code& ec) const
+  {
+    std::size_t size = option.size(impl.protocol_);
+    socket_ops::getsockopt(impl.socket_, impl.state_,
+        option.level(impl.protocol_), option.name(impl.protocol_),
+        option.data(impl.protocol_), &size, ec);
+    if (!ec)
+      option.resize(impl.protocol_, size);
+    return ec;
+  }
+
+  // Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    endpoint_type endpoint;
+    std::size_t addr_len = endpoint.capacity();
+    if (socket_ops::getsockname(impl.socket_, endpoint.data(), &addr_len, ec))
+      return endpoint_type();
+    endpoint.resize(addr_len);
+    return endpoint;
+  }
+
+  // Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    endpoint_type endpoint;
+    std::size_t addr_len = endpoint.capacity();
+    if (socket_ops::getpeername(impl.socket_,
+          endpoint.data(), &addr_len, false, ec))
+      return endpoint_type();
+    endpoint.resize(addr_len);
+    return endpoint;
+  }
+
+  // Disable sends or receives on the socket.
+  asio::error_code shutdown(base_implementation_type& impl,
+      socket_base::shutdown_type what, asio::error_code& ec)
+  {
+    socket_ops::shutdown(impl.socket_, what, ec);
+    return ec;
+  }
+
+  // Send a datagram to the specified endpoint. Returns the number of bytes
+  // sent.
+  template <typename ConstBufferSequence>
+  size_t send_to(implementation_type& impl, const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_sendto(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), flags,
+        destination.data(), destination.size(), ec);
+  }
+
+  // Wait until data can be sent without blocking.
+  size_t send_to(implementation_type& impl, const null_buffers&,
+      const endpoint_type&, socket_base::message_flags,
+      asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous send. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_send_to(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags,
+      Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_sendto_op<ConstBufferSequence,
+        endpoint_type, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.socket_, buffers, destination, flags, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_send_to"));
+
+    start_op(impl, reactor::write_op, p.p, is_continuation, true, false);
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous wait until data can be sent without blocking.
+  template <typename Handler>
+  void async_send_to(implementation_type& impl, const null_buffers&,
+      const endpoint_type&, socket_base::message_flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_send_to(null_buffers)"));
+
+    start_op(impl, reactor::write_op, p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+  // Receive a datagram with the endpoint of the sender. Returns the number of
+  // bytes received.
+  template <typename MutableBufferSequence>
+  size_t receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    std::size_t addr_len = sender_endpoint.capacity();
+    std::size_t bytes_recvd = socket_ops::sync_recvfrom(
+        impl.socket_, impl.state_, bufs.buffers(), bufs.count(),
+        flags, sender_endpoint.data(), &addr_len, ec);
+
+    if (!ec)
+      sender_endpoint.resize(addr_len);
+
+    return bytes_recvd;
+  }
+
+  // Wait until data can be received without blocking.
+  size_t receive_from(implementation_type& impl, const null_buffers&,
+      endpoint_type& sender_endpoint, socket_base::message_flags,
+      asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+
+    // Reset endpoint since it can be given no sensible value at this time.
+    sender_endpoint = endpoint_type();
+
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received and
+  // the sender_endpoint object must both be valid for the lifetime of the
+  // asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers, endpoint_type& sender_endpoint,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_recvfrom_op<MutableBufferSequence,
+        endpoint_type, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    int protocol = impl.protocol_.type();
+    p.p = new (p.v) op(impl.socket_, protocol,
+        buffers, sender_endpoint, flags, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_receive_from"));
+
+    start_op(impl,
+        (flags & socket_base::message_out_of_band)
+          ? reactor::except_op : reactor::read_op,
+        p.p, is_continuation, true, false);
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive_from(implementation_type& impl,
+      const null_buffers&, endpoint_type& sender_endpoint,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_receive_from(null_buffers)"));
+
+    // Reset endpoint since it can be given no sensible value at this time.
+    sender_endpoint = endpoint_type();
+
+    start_op(impl,
+        (flags & socket_base::message_out_of_band)
+          ? reactor::except_op : reactor::read_op,
+        p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+  // Accept a new connection.
+  template <typename Socket>
+  asio::error_code accept(implementation_type& impl,
+      Socket& peer, endpoint_type* peer_endpoint, asio::error_code& ec)
+  {
+    // We cannot accept a socket that is already open.
+    if (peer.is_open())
+    {
+      ec = asio::error::already_open;
+      return ec;
+    }
+
+    std::size_t addr_len = peer_endpoint ? peer_endpoint->capacity() : 0;
+    socket_holder new_socket(socket_ops::sync_accept(impl.socket_,
+          impl.state_, peer_endpoint ? peer_endpoint->data() : 0,
+          peer_endpoint ? &addr_len : 0, ec));
+
+    // On success, assign new connection to peer socket object.
+    if (new_socket.get() != invalid_socket)
+    {
+      if (peer_endpoint)
+        peer_endpoint->resize(addr_len);
+      peer.assign(impl.protocol_, new_socket.get(), ec);
+      if (!ec)
+        new_socket.release();
+    }
+
+    return ec;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  // Accept a new connection.
+  typename Protocol::socket accept(implementation_type& impl,
+      io_context* peer_io_context, endpoint_type* peer_endpoint,
+      asio::error_code& ec)
+  {
+    typename Protocol::socket peer(
+        peer_io_context ? *peer_io_context : io_context_);
+
+    std::size_t addr_len = peer_endpoint ? peer_endpoint->capacity() : 0;
+    socket_holder new_socket(socket_ops::sync_accept(impl.socket_,
+          impl.state_, peer_endpoint ? peer_endpoint->data() : 0,
+          peer_endpoint ? &addr_len : 0, ec));
+
+    // On success, assign new connection to peer socket object.
+    if (new_socket.get() != invalid_socket)
+    {
+      if (peer_endpoint)
+        peer_endpoint->resize(addr_len);
+      peer.assign(impl.protocol_, new_socket.get(), ec);
+      if (!ec)
+        new_socket.release();
+    }
+
+    return peer;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  // Start an asynchronous accept. The peer and peer_endpoint objects must be
+  // valid until the accept's handler is invoked.
+  template <typename Socket, typename Handler>
+  void async_accept(implementation_type& impl, Socket& peer,
+      endpoint_type* peer_endpoint, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_accept_op<Socket, Protocol, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.socket_, impl.state_, peer,
+        impl.protocol_, peer_endpoint, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_accept"));
+
+    start_accept_op(impl, p.p, is_continuation, peer.is_open());
+    p.v = p.p = 0;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  // Start an asynchronous accept. The peer_endpoint object must be valid until
+  // the accept's handler is invoked.
+  template <typename Handler>
+  void async_accept(implementation_type& impl,
+      asio::io_context* peer_io_context,
+      endpoint_type* peer_endpoint, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_move_accept_op<Protocol, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(peer_io_context ? *peer_io_context : io_context_,
+        impl.socket_, impl.state_, impl.protocol_, peer_endpoint, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_accept"));
+
+    start_accept_op(impl, p.p, is_continuation, false);
+    p.v = p.p = 0;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  // Connect the socket to the specified endpoint.
+  asio::error_code connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    socket_ops::sync_connect(impl.socket_,
+        peer_endpoint.data(), peer_endpoint.size(), ec);
+    return ec;
+  }
+
+  // Start an asynchronous connect.
+  template <typename Handler>
+  void async_connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_connect_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.socket_, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_connect"));
+
+    start_connect_op(impl, p.p, is_continuation,
+        peer_endpoint.data(), peer_endpoint.size());
+    p.v = p.p = 0;
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_socket_service_base.hpp b/subprojects/asio/include/asio/detail/reactive_socket_service_base.hpp
new file mode 100644
index 000000000..ccd497e80
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_socket_service_base.hpp
@@ -0,0 +1,511 @@
+//
+// detail/reactive_socket_service_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_BASE_HPP
+#define ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_IOCP) \
+  && !defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/buffer.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/socket_base.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactive_null_buffers_op.hpp"
+#include "asio/detail/reactive_socket_recv_op.hpp"
+#include "asio/detail/reactive_socket_recvmsg_op.hpp"
+#include "asio/detail/reactive_socket_send_op.hpp"
+#include "asio/detail/reactive_wait_op.hpp"
+#include "asio/detail/reactor.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_holder.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class reactive_socket_service_base
+{
+public:
+  // The native type of a socket.
+  typedef socket_type native_handle_type;
+
+  // The implementation type of the socket.
+  struct base_implementation_type
+  {
+    // The native socket representation.
+    socket_type socket_;
+
+    // The current state of the socket.
+    socket_ops::state_type state_;
+
+    // Per-descriptor data used by the reactor.
+    reactor::per_descriptor_data reactor_data_;
+  };
+
+  // Constructor.
+  ASIO_DECL reactive_socket_service_base(
+      asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void base_shutdown();
+
+  // Construct a new socket implementation.
+  ASIO_DECL void construct(base_implementation_type& impl);
+
+  // Move-construct a new socket implementation.
+  ASIO_DECL void base_move_construct(base_implementation_type& impl,
+      base_implementation_type& other_impl);
+
+  // Move-assign from another socket implementation.
+  ASIO_DECL void base_move_assign(base_implementation_type& impl,
+      reactive_socket_service_base& other_service,
+      base_implementation_type& other_impl);
+
+  // Destroy a socket implementation.
+  ASIO_DECL void destroy(base_implementation_type& impl);
+
+  // Determine whether the socket is open.
+  bool is_open(const base_implementation_type& impl) const
+  {
+    return impl.socket_ != invalid_socket;
+  }
+
+  // Destroy a socket implementation.
+  ASIO_DECL asio::error_code close(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Release ownership of the socket.
+  ASIO_DECL socket_type release(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Get the native socket representation.
+  native_handle_type native_handle(base_implementation_type& impl)
+  {
+    return impl.socket_;
+  }
+
+  // Cancel all operations associated with the socket.
+  ASIO_DECL asio::error_code cancel(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const base_implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return socket_ops::sockatmark(impl.socket_, ec);
+  }
+
+  // Determine the number of bytes available for reading.
+  std::size_t available(const base_implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return socket_ops::available(impl.socket_, ec);
+  }
+
+  // Place the socket into the state where it will listen for new connections.
+  asio::error_code listen(base_implementation_type& impl,
+      int backlog, asio::error_code& ec)
+  {
+    socket_ops::listen(impl.socket_, backlog, ec);
+    return ec;
+  }
+
+  // Perform an IO control command on the socket.
+  template <typename IO_Control_Command>
+  asio::error_code io_control(base_implementation_type& impl,
+      IO_Control_Command& command, asio::error_code& ec)
+  {
+    socket_ops::ioctl(impl.socket_, impl.state_, command.name(),
+        static_cast<ioctl_arg_type*>(command.data()), ec);
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the socket.
+  bool non_blocking(const base_implementation_type& impl) const
+  {
+    return (impl.state_ & socket_ops::user_set_non_blocking) != 0;
+  }
+
+  // Sets the non-blocking mode of the socket.
+  asio::error_code non_blocking(base_implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    socket_ops::set_user_non_blocking(impl.socket_, impl.state_, mode, ec);
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const base_implementation_type& impl) const
+  {
+    return (impl.state_ & socket_ops::internal_non_blocking) != 0;
+  }
+
+  // Sets the non-blocking mode of the native socket implementation.
+  asio::error_code native_non_blocking(base_implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    socket_ops::set_internal_non_blocking(impl.socket_, impl.state_, mode, ec);
+    return ec;
+  }
+
+  // Wait for the socket to become ready to read, ready to write, or to have
+  // pending error conditions.
+  asio::error_code wait(base_implementation_type& impl,
+      socket_base::wait_type w, asio::error_code& ec)
+  {
+    switch (w)
+    {
+    case socket_base::wait_read:
+      socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+      break;
+    case socket_base::wait_write:
+      socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);
+      break;
+    case socket_base::wait_error:
+      socket_ops::poll_error(impl.socket_, impl.state_, -1, ec);
+      break;
+    default:
+      ec = asio::error::invalid_argument;
+      break;
+    }
+
+    return ec;
+  }
+
+  // Asynchronously wait for the socket to become ready to read, ready to
+  // write, or to have pending error conditions.
+  template <typename Handler>
+  void async_wait(base_implementation_type& impl,
+      socket_base::wait_type w, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_wait_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_wait"));
+
+    int op_type;
+    switch (w)
+    {
+      case socket_base::wait_read:
+        op_type = reactor::read_op;
+        break;
+      case socket_base::wait_write:
+        op_type = reactor::write_op;
+        break;
+      case socket_base::wait_error:
+        op_type = reactor::except_op;
+        break;
+      default:
+        p.p->ec_ = asio::error::invalid_argument;
+        reactor_.post_immediate_completion(p.p, is_continuation);
+        p.v = p.p = 0;
+        return;
+    }
+
+    start_op(impl, op_type, p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+  // Send the given data to the peer.
+  template <typename ConstBufferSequence>
+  size_t send(base_implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_send(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), flags, bufs.all_empty(), ec);
+  }
+
+  // Wait until data can be sent without blocking.
+  size_t send(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous send. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_send(base_implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_send_op<ConstBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.socket_, impl.state_, buffers, flags, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_send"));
+
+    start_op(impl, reactor::write_op, p.p, is_continuation, true,
+        ((impl.state_ & socket_ops::stream_oriented)
+          && buffer_sequence_adapter<asio::const_buffer,
+            ConstBufferSequence>::all_empty(buffers)));
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous wait until data can be sent without blocking.
+  template <typename Handler>
+  void async_send(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_send(null_buffers)"));
+
+    start_op(impl, reactor::write_op, p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+  // Receive some data from the peer. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  size_t receive(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_recv(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), flags, bufs.all_empty(), ec);
+  }
+
+  // Wait until data can be received without blocking.
+  size_t receive(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_recv_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.socket_, impl.state_, buffers, flags, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_receive"));
+
+    start_op(impl,
+        (flags & socket_base::message_out_of_band)
+          ? reactor::except_op : reactor::read_op,
+        p.p, is_continuation,
+        (flags & socket_base::message_out_of_band) == 0,
+        ((impl.state_ & socket_ops::stream_oriented)
+          && buffer_sequence_adapter<asio::mutable_buffer,
+            MutableBufferSequence>::all_empty(buffers)));
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_receive(null_buffers)"));
+
+    start_op(impl,
+        (flags & socket_base::message_out_of_band)
+          ? reactor::except_op : reactor::read_op,
+        p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+  // Receive some data with associated flags. Returns the number of bytes
+  // received.
+  template <typename MutableBufferSequence>
+  size_t receive_with_flags(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_recvmsg(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), in_flags, out_flags, ec);
+  }
+
+  // Wait until data can be received without blocking.
+  size_t receive_with_flags(base_implementation_type& impl,
+      const null_buffers&, socket_base::message_flags,
+      socket_base::message_flags& out_flags, asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+
+    // Clear out_flags, since we cannot give it any other sensible value when
+    // performing a null_buffers operation.
+    out_flags = 0;
+
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive_with_flags(base_implementation_type& impl,
+      const MutableBufferSequence& buffers, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_socket_recvmsg_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.socket_, buffers, in_flags, out_flags, handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_receive_with_flags"));
+
+    start_op(impl,
+        (in_flags & socket_base::message_out_of_band)
+          ? reactor::except_op : reactor::read_op,
+        p.p, is_continuation,
+        (in_flags & socket_base::message_out_of_band) == 0, false);
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive_with_flags(base_implementation_type& impl,
+      const null_buffers&, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef reactive_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
+          &impl, impl.socket_, "async_receive_with_flags(null_buffers)"));
+
+    // Clear out_flags, since we cannot give it any other sensible value when
+    // performing a null_buffers operation.
+    out_flags = 0;
+
+    start_op(impl,
+        (in_flags & socket_base::message_out_of_band)
+          ? reactor::except_op : reactor::read_op,
+        p.p, is_continuation, false, false);
+    p.v = p.p = 0;
+  }
+
+protected:
+  // Open a new socket implementation.
+  ASIO_DECL asio::error_code do_open(
+      base_implementation_type& impl, int af,
+      int type, int protocol, asio::error_code& ec);
+
+  // Assign a native socket to a socket implementation.
+  ASIO_DECL asio::error_code do_assign(
+      base_implementation_type& impl, int type,
+      const native_handle_type& native_socket, asio::error_code& ec);
+
+  // Start the asynchronous read or write operation.
+  ASIO_DECL void start_op(base_implementation_type& impl, int op_type,
+      reactor_op* op, bool is_continuation, bool is_non_blocking, bool noop);
+
+  // Start the asynchronous accept operation.
+  ASIO_DECL void start_accept_op(base_implementation_type& impl,
+      reactor_op* op, bool is_continuation, bool peer_is_open);
+
+  // Start the asynchronous connect operation.
+  ASIO_DECL void start_connect_op(base_implementation_type& impl,
+      reactor_op* op, bool is_continuation,
+      const socket_addr_type* addr, size_t addrlen);
+
+  // The io_context that owns this socket service.
+  io_context& io_context_;
+
+  // The selector that performs event demultiplexing for the service.
+  reactor& reactor_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/reactive_socket_service_base.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // !defined(ASIO_HAS_IOCP)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_BASE_HPP
diff --git a/subprojects/asio/include/asio/detail/reactive_wait_op.hpp b/subprojects/asio/include/asio/detail/reactive_wait_op.hpp
new file mode 100644
index 000000000..616d8b115
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactive_wait_op.hpp
@@ -0,0 +1,90 @@
+//
+// detail/reactive_wait_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTIVE_WAIT_OP_HPP
+#define ASIO_DETAIL_REACTIVE_WAIT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class reactive_wait_op : public reactor_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(reactive_wait_op);
+
+  reactive_wait_op(Handler& handler)
+    : reactor_op(&reactive_wait_op::do_perform,
+        &reactive_wait_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static status do_perform(reactor_op*)
+  {
+    return done;
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    reactive_wait_op* o(static_cast<reactive_wait_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(o->handler_, o->ec_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTIVE_WAIT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactor.hpp b/subprojects/asio/include/asio/detail/reactor.hpp
new file mode 100644
index 000000000..47502764f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactor.hpp
@@ -0,0 +1,32 @@
+//
+// detail/reactor.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTOR_HPP
+#define ASIO_DETAIL_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/reactor_fwd.hpp"
+
+#if defined(ASIO_HAS_EPOLL)
+# include "asio/detail/epoll_reactor.hpp"
+#elif defined(ASIO_HAS_KQUEUE)
+# include "asio/detail/kqueue_reactor.hpp"
+#elif defined(ASIO_HAS_DEV_POLL)
+# include "asio/detail/dev_poll_reactor.hpp"
+#elif defined(ASIO_HAS_IOCP) || defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/null_reactor.hpp"
+#else
+# include "asio/detail/select_reactor.hpp"
+#endif
+
+#endif // ASIO_DETAIL_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/reactor_fwd.hpp b/subprojects/asio/include/asio/detail/reactor_fwd.hpp
new file mode 100644
index 000000000..a4555c3db
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactor_fwd.hpp
@@ -0,0 +1,40 @@
+//
+// detail/reactor_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTOR_FWD_HPP
+#define ASIO_DETAIL_REACTOR_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_IOCP) || defined(ASIO_WINDOWS_RUNTIME)
+typedef class null_reactor reactor;
+#elif defined(ASIO_HAS_IOCP)
+typedef class select_reactor reactor;
+#elif defined(ASIO_HAS_EPOLL)
+typedef class epoll_reactor reactor;
+#elif defined(ASIO_HAS_KQUEUE)
+typedef class kqueue_reactor reactor;
+#elif defined(ASIO_HAS_DEV_POLL)
+typedef class dev_poll_reactor reactor;
+#else
+typedef class select_reactor reactor;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_REACTOR_FWD_HPP
diff --git a/subprojects/asio/include/asio/detail/reactor_op.hpp b/subprojects/asio/include/asio/detail/reactor_op.hpp
new file mode 100644
index 000000000..faad1a775
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactor_op.hpp
@@ -0,0 +1,65 @@
+//
+// detail/reactor_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTOR_OP_HPP
+#define ASIO_DETAIL_REACTOR_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class reactor_op
+  : public operation
+{
+public:
+  // The error code to be passed to the completion handler.
+  asio::error_code ec_;
+
+  // The number of bytes transferred, to be passed to the completion handler.
+  std::size_t bytes_transferred_;
+
+  // Status returned by perform function. May be used to decide whether it is
+  // worth performing more operations on the descriptor immediately.
+  enum status { not_done, done, done_and_exhausted };
+
+  // Perform the operation. Returns true if it is finished.
+  status perform()
+  {
+    return perform_func_(this);
+  }
+
+protected:
+  typedef status (*perform_func_type)(reactor_op*);
+
+  reactor_op(perform_func_type perform_func, func_type complete_func)
+    : operation(complete_func),
+      bytes_transferred_(0),
+      perform_func_(perform_func)
+  {
+  }
+
+private:
+  perform_func_type perform_func_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTOR_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/reactor_op_queue.hpp b/subprojects/asio/include/asio/detail/reactor_op_queue.hpp
new file mode 100644
index 000000000..898f31d1c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/reactor_op_queue.hpp
@@ -0,0 +1,168 @@
+//
+// detail/reactor_op_queue.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REACTOR_OP_QUEUE_HPP
+#define ASIO_DETAIL_REACTOR_OP_QUEUE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/hash_map.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Descriptor>
+class reactor_op_queue
+  : private noncopyable
+{
+public:
+  typedef Descriptor key_type;
+
+  struct mapped_type : op_queue<reactor_op>
+  {
+    mapped_type() {}
+    mapped_type(const mapped_type&) {}
+    void operator=(const mapped_type&) {}
+  };
+
+  typedef typename hash_map<key_type, mapped_type>::value_type value_type;
+  typedef typename hash_map<key_type, mapped_type>::iterator iterator;
+
+  // Constructor.
+  reactor_op_queue()
+    : operations_()
+  {
+  }
+
+  // Obtain iterators to all registered descriptors.
+  iterator begin() { return operations_.begin(); }
+  iterator end() { return operations_.end(); }
+
+  // Add a new operation to the queue. Returns true if this is the only
+  // operation for the given descriptor, in which case the reactor's event
+  // demultiplexing function call may need to be interrupted and restarted.
+  bool enqueue_operation(Descriptor descriptor, reactor_op* op)
+  {
+    std::pair<iterator, bool> entry =
+      operations_.insert(value_type(descriptor, mapped_type()));
+    entry.first->second.push(op);
+    return entry.second;
+  }
+
+  // Cancel all operations associated with the descriptor identified by the
+  // supplied iterator. Any operations pending for the descriptor will be
+  // cancelled. Returns true if any operations were cancelled, in which case
+  // the reactor's event demultiplexing function may need to be interrupted and
+  // restarted.
+  bool cancel_operations(iterator i, op_queue<operation>& ops,
+      const asio::error_code& ec =
+        asio::error::operation_aborted)
+  {
+    if (i != operations_.end())
+    {
+      while (reactor_op* op = i->second.front())
+      {
+        op->ec_ = ec;
+        i->second.pop();
+        ops.push(op);
+      }
+      operations_.erase(i);
+      return true;
+    }
+
+    return false;
+  }
+
+  // Cancel all operations associated with the descriptor. Any operations
+  // pending for the descriptor will be cancelled. Returns true if any
+  // operations were cancelled, in which case the reactor's event
+  // demultiplexing function may need to be interrupted and restarted.
+  bool cancel_operations(Descriptor descriptor, op_queue<operation>& ops,
+      const asio::error_code& ec =
+        asio::error::operation_aborted)
+  {
+    return this->cancel_operations(operations_.find(descriptor), ops, ec);
+  }
+
+  // Whether there are no operations in the queue.
+  bool empty() const
+  {
+    return operations_.empty();
+  }
+
+  // Determine whether there are any operations associated with the descriptor.
+  bool has_operation(Descriptor descriptor) const
+  {
+    return operations_.find(descriptor) != operations_.end();
+  }
+
+  // Perform the operations corresponding to the descriptor identified by the
+  // supplied iterator. Returns true if there are still unfinished operations
+  // queued for the descriptor.
+  bool perform_operations(iterator i, op_queue<operation>& ops)
+  {
+    if (i != operations_.end())
+    {
+      while (reactor_op* op = i->second.front())
+      {
+        if (op->perform())
+        {
+          i->second.pop();
+          ops.push(op);
+        }
+        else
+        {
+          return true;
+        }
+      }
+      operations_.erase(i);
+    }
+    return false;
+  }
+
+  // Perform the operations corresponding to the descriptor. Returns true if
+  // there are still unfinished operations queued for the descriptor.
+  bool perform_operations(Descriptor descriptor, op_queue<operation>& ops)
+  {
+    return this->perform_operations(operations_.find(descriptor), ops);
+  }
+
+  // Get all operations owned by the queue.
+  void get_all_operations(op_queue<operation>& ops)
+  {
+    iterator i = operations_.begin();
+    while (i != operations_.end())
+    {
+      iterator op_iter = i++;
+      ops.push(op_iter->second);
+      operations_.erase(op_iter);
+    }
+  }
+
+private:
+  // The operations that are currently executing asynchronously.
+  hash_map<key_type, mapped_type> operations_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_REACTOR_OP_QUEUE_HPP
diff --git a/subprojects/asio/include/asio/detail/recycling_allocator.hpp b/subprojects/asio/include/asio/detail/recycling_allocator.hpp
new file mode 100644
index 000000000..964af1da6
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/recycling_allocator.hpp
@@ -0,0 +1,104 @@
+//
+// detail/recycling_allocator.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_RECYCLING_ALLOCATOR_HPP
+#define ASIO_DETAIL_RECYCLING_ALLOCATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/thread_context.hpp"
+#include "asio/detail/thread_info_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+class recycling_allocator
+{
+public:
+  typedef T value_type;
+
+  template <typename U>
+  struct rebind
+  {
+    typedef recycling_allocator<U> other;
+  };
+
+  recycling_allocator()
+  {
+  }
+
+  template <typename U>
+  recycling_allocator(const recycling_allocator<U>&)
+  {
+  }
+
+  T* allocate(std::size_t n)
+  {
+    typedef thread_context::thread_call_stack call_stack;
+    void* p = thread_info_base::allocate(call_stack::top(), sizeof(T) * n);
+    return static_cast<T*>(p);
+  }
+
+  void deallocate(T* p, std::size_t n)
+  {
+    typedef thread_context::thread_call_stack call_stack;
+    thread_info_base::deallocate(call_stack::top(), p, sizeof(T) * n);
+  }
+};
+
+template <>
+class recycling_allocator<void>
+{
+public:
+  typedef void value_type;
+
+  template <typename U>
+  struct rebind
+  {
+    typedef recycling_allocator<U> other;
+  };
+
+  recycling_allocator()
+  {
+  }
+
+  template <typename U>
+  recycling_allocator(const recycling_allocator<U>&)
+  {
+  }
+};
+
+template <typename Allocator>
+struct get_recycling_allocator
+{
+  typedef Allocator type;
+  static type get(const Allocator& a) { return a; }
+};
+
+template <typename T>
+struct get_recycling_allocator<std::allocator<T> >
+{
+  typedef recycling_allocator<T> type;
+  static type get(const std::allocator<T>&) { return type(); }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_RECYCLING_ALLOCATOR_HPP
diff --git a/subprojects/asio/include/asio/detail/regex_fwd.hpp b/subprojects/asio/include/asio/detail/regex_fwd.hpp
new file mode 100644
index 000000000..dcf7d06e3
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/regex_fwd.hpp
@@ -0,0 +1,35 @@
+//
+// detail/regex_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_REGEX_FWD_HPP
+#define ASIO_DETAIL_REGEX_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if defined(ASIO_HAS_BOOST_REGEX)
+
+#include <boost/regex_fwd.hpp>
+#include <boost/regex/v4/match_flags.hpp>
+
+namespace boost {
+
+template <class BidiIterator>
+struct sub_match;
+
+template <class BidiIterator, class Allocator>
+class match_results;
+
+} // namespace boost
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+
+#endif // ASIO_DETAIL_REGEX_FWD_HPP
diff --git a/subprojects/asio/include/asio/detail/resolve_endpoint_op.hpp b/subprojects/asio/include/asio/detail/resolve_endpoint_op.hpp
new file mode 100644
index 000000000..8eee2f98b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/resolve_endpoint_op.hpp
@@ -0,0 +1,122 @@
+//
+// detail/resolve_endpoint_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_RESOLVER_ENDPOINT_OP_HPP
+#define ASIO_DETAIL_RESOLVER_ENDPOINT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/ip/basic_resolver_results.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/resolve_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol, typename Handler>
+class resolve_endpoint_op : public resolve_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(resolve_endpoint_op);
+
+  typedef typename Protocol::endpoint endpoint_type;
+  typedef asio::ip::basic_resolver_results<Protocol> results_type;
+
+  resolve_endpoint_op(socket_ops::weak_cancel_token_type cancel_token,
+      const endpoint_type& endpoint, io_context_impl& ioc, Handler& handler)
+    : resolve_op(&resolve_endpoint_op::do_complete),
+      cancel_token_(cancel_token),
+      endpoint_(endpoint),
+      io_context_impl_(ioc),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the operation object.
+    resolve_endpoint_op* o(static_cast<resolve_endpoint_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    if (owner && owner != &o->io_context_impl_)
+    {
+      // The operation is being run on the worker io_context. Time to perform
+      // the resolver operation.
+    
+      // Perform the blocking endpoint resolution operation.
+      char host_name[NI_MAXHOST];
+      char service_name[NI_MAXSERV];
+      socket_ops::background_getnameinfo(o->cancel_token_, o->endpoint_.data(),
+          o->endpoint_.size(), host_name, NI_MAXHOST, service_name, NI_MAXSERV,
+          o->endpoint_.protocol().type(), o->ec_);
+      o->results_ = results_type::create(o->endpoint_, host_name, service_name);
+
+      // Pass operation back to main io_context for completion.
+      o->io_context_impl_.post_deferred_completion(o);
+      p.v = p.p = 0;
+    }
+    else
+    {
+      // The operation has been returned to the main io_context. The completion
+      // handler is ready to be delivered.
+
+      ASIO_HANDLER_COMPLETION((*o));
+
+      // Make a copy of the handler so that the memory can be deallocated
+      // before the upcall is made. Even if we're not about to make an upcall,
+      // a sub-object of the handler may be the true owner of the memory
+      // associated with the handler. Consequently, a local copy of the handler
+      // is required to ensure that any owning sub-object remains valid until
+      // after we have deallocated the memory here.
+      detail::binder2<Handler, asio::error_code, results_type>
+        handler(o->handler_, o->ec_, o->results_);
+      p.h = asio::detail::addressof(handler.handler_);
+      p.reset();
+
+      if (owner)
+      {
+        fenced_block b(fenced_block::half);
+        ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
+        w.complete(handler, handler.handler_);
+        ASIO_HANDLER_INVOCATION_END;
+      }
+    }
+  }
+
+private:
+  socket_ops::weak_cancel_token_type cancel_token_;
+  endpoint_type endpoint_;
+  io_context_impl& io_context_impl_;
+  Handler handler_;
+  results_type results_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_RESOLVER_ENDPOINT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/resolve_op.hpp b/subprojects/asio/include/asio/detail/resolve_op.hpp
new file mode 100644
index 000000000..a528aa825
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/resolve_op.hpp
@@ -0,0 +1,45 @@
+//
+// detail/resolve_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_RESOLVE_OP_HPP
+#define ASIO_DETAIL_RESOLVE_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/error.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class resolve_op : public operation
+{
+public:
+  // The error code to be passed to the completion handler.
+  asio::error_code ec_;
+
+protected:
+  resolve_op(func_type complete_func)
+    : operation(complete_func)
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_RESOLVE_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/resolve_query_op.hpp b/subprojects/asio/include/asio/detail/resolve_query_op.hpp
new file mode 100644
index 000000000..0ec5a3210
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/resolve_query_op.hpp
@@ -0,0 +1,134 @@
+//
+// detail/resolve_query_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_RESOLVE_QUERY_OP_HPP
+#define ASIO_DETAIL_RESOLVE_QUERY_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+#include "asio/ip/basic_resolver_results.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/resolve_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol, typename Handler>
+class resolve_query_op : public resolve_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(resolve_query_op);
+
+  typedef asio::ip::basic_resolver_query<Protocol> query_type;
+  typedef asio::ip::basic_resolver_results<Protocol> results_type;
+
+  resolve_query_op(socket_ops::weak_cancel_token_type cancel_token,
+      const query_type& query, io_context_impl& ioc, Handler& handler)
+    : resolve_op(&resolve_query_op::do_complete),
+      cancel_token_(cancel_token),
+      query_(query),
+      io_context_impl_(ioc),
+      handler_(ASIO_MOVE_CAST(Handler)(handler)),
+      addrinfo_(0)
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  ~resolve_query_op()
+  {
+    if (addrinfo_)
+      socket_ops::freeaddrinfo(addrinfo_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the operation object.
+    resolve_query_op* o(static_cast<resolve_query_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+
+    if (owner && owner != &o->io_context_impl_)
+    {
+      // The operation is being run on the worker io_context. Time to perform
+      // the resolver operation.
+    
+      // Perform the blocking host resolution operation.
+      socket_ops::background_getaddrinfo(o->cancel_token_,
+          o->query_.host_name().c_str(), o->query_.service_name().c_str(),
+          o->query_.hints(), &o->addrinfo_, o->ec_);
+
+      // Pass operation back to main io_context for completion.
+      o->io_context_impl_.post_deferred_completion(o);
+      p.v = p.p = 0;
+    }
+    else
+    {
+      // The operation has been returned to the main io_context. The completion
+      // handler is ready to be delivered.
+
+      // Take ownership of the operation's outstanding work.
+      handler_work<Handler> w(o->handler_);
+
+      ASIO_HANDLER_COMPLETION((*o));
+
+      // Make a copy of the handler so that the memory can be deallocated
+      // before the upcall is made. Even if we're not about to make an upcall,
+      // a sub-object of the handler may be the true owner of the memory
+      // associated with the handler. Consequently, a local copy of the handler
+      // is required to ensure that any owning sub-object remains valid until
+      // after we have deallocated the memory here.
+      detail::binder2<Handler, asio::error_code, results_type>
+        handler(o->handler_, o->ec_, results_type());
+      p.h = asio::detail::addressof(handler.handler_);
+      if (o->addrinfo_)
+      {
+        handler.arg2_ = results_type::create(o->addrinfo_,
+            o->query_.host_name(), o->query_.service_name());
+      }
+      p.reset();
+
+      if (owner)
+      {
+        fenced_block b(fenced_block::half);
+        ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
+        w.complete(handler, handler.handler_);
+        ASIO_HANDLER_INVOCATION_END;
+      }
+    }
+  }
+
+private:
+  socket_ops::weak_cancel_token_type cancel_token_;
+  query_type query_;
+  io_context_impl& io_context_impl_;
+  Handler handler_;
+  asio::detail::addrinfo_type* addrinfo_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_RESOLVE_QUERY_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/resolver_service.hpp b/subprojects/asio/include/asio/detail/resolver_service.hpp
new file mode 100644
index 000000000..11a94d135
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/resolver_service.hpp
@@ -0,0 +1,145 @@
+//
+// detail/resolver_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_RESOLVER_SERVICE_HPP
+#define ASIO_DETAIL_RESOLVER_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/ip/basic_resolver_query.hpp"
+#include "asio/ip/basic_resolver_results.hpp"
+#include "asio/detail/concurrency_hint.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/resolve_endpoint_op.hpp"
+#include "asio/detail/resolve_query_op.hpp"
+#include "asio/detail/resolver_service_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol>
+class resolver_service :
+  public service_base<resolver_service<Protocol> >,
+  public resolver_service_base
+{
+public:
+  // The implementation type of the resolver. A cancellation token is used to
+  // indicate to the background thread that the operation has been cancelled.
+  typedef socket_ops::shared_cancel_token_type implementation_type;
+
+  // The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  // The query type.
+  typedef asio::ip::basic_resolver_query<Protocol> query_type;
+
+  // The results type.
+  typedef asio::ip::basic_resolver_results<Protocol> results_type;
+
+  // Constructor.
+  resolver_service(asio::io_context& io_context)
+    : service_base<resolver_service<Protocol> >(io_context),
+      resolver_service_base(io_context)
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    this->base_shutdown();
+  }
+
+  // Perform any fork-related housekeeping.
+  void notify_fork(asio::io_context::fork_event fork_ev)
+  {
+    this->base_notify_fork(fork_ev);
+  }
+
+  // Resolve a query to a list of entries.
+  results_type resolve(implementation_type&, const query_type& query,
+      asio::error_code& ec)
+  {
+    asio::detail::addrinfo_type* address_info = 0;
+
+    socket_ops::getaddrinfo(query.host_name().c_str(),
+        query.service_name().c_str(), query.hints(), &address_info, ec);
+    auto_addrinfo auto_address_info(address_info);
+
+    return ec ? results_type() : results_type::create(
+        address_info, query.host_name(), query.service_name());
+  }
+
+  // Asynchronously resolve a query to a list of entries.
+  template <typename Handler>
+  void async_resolve(implementation_type& impl,
+      const query_type& query, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef resolve_query_op<Protocol, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl, query, io_context_impl_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_impl_.context(),
+          *p.p, "resolver", &impl, 0, "async_resolve"));
+
+    start_resolve_op(p.p);
+    p.v = p.p = 0;
+  }
+
+  // Resolve an endpoint to a list of entries.
+  results_type resolve(implementation_type&,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    char host_name[NI_MAXHOST];
+    char service_name[NI_MAXSERV];
+    socket_ops::sync_getnameinfo(endpoint.data(), endpoint.size(),
+        host_name, NI_MAXHOST, service_name, NI_MAXSERV,
+        endpoint.protocol().type(), ec);
+
+    return ec ? results_type() : results_type::create(
+        endpoint, host_name, service_name);
+  }
+
+  // Asynchronously resolve an endpoint to a list of entries.
+  template <typename Handler>
+  void async_resolve(implementation_type& impl,
+      const endpoint_type& endpoint, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef resolve_endpoint_op<Protocol, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl, endpoint, io_context_impl_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_impl_.context(),
+          *p.p, "resolver", &impl, 0, "async_resolve"));
+
+    start_resolve_op(p.p);
+    p.v = p.p = 0;
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_RESOLVER_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/resolver_service_base.hpp b/subprojects/asio/include/asio/detail/resolver_service_base.hpp
new file mode 100644
index 000000000..10a792241
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/resolver_service_base.hpp
@@ -0,0 +1,140 @@
+//
+// detail/resolver_service_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_RESOLVER_SERVICE_BASE_HPP
+#define ASIO_DETAIL_RESOLVER_SERVICE_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/error.hpp"
+#include "asio/executor_work_guard.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/resolve_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/detail/thread.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class resolver_service_base
+{
+public:
+  // The implementation type of the resolver. A cancellation token is used to
+  // indicate to the background thread that the operation has been cancelled.
+  typedef socket_ops::shared_cancel_token_type implementation_type;
+
+  // Constructor.
+  ASIO_DECL resolver_service_base(asio::io_context& io_context);
+
+  // Destructor.
+  ASIO_DECL ~resolver_service_base();
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void base_shutdown();
+
+  // Perform any fork-related housekeeping.
+  ASIO_DECL void base_notify_fork(
+      asio::io_context::fork_event fork_ev);
+
+  // Construct a new resolver implementation.
+  ASIO_DECL void construct(implementation_type& impl);
+
+  // Destroy a resolver implementation.
+  ASIO_DECL void destroy(implementation_type&);
+
+  // Move-construct a new resolver implementation.
+  ASIO_DECL void move_construct(implementation_type& impl,
+      implementation_type& other_impl);
+
+  // Move-assign from another resolver implementation.
+  ASIO_DECL void move_assign(implementation_type& impl,
+      resolver_service_base& other_service,
+      implementation_type& other_impl);
+
+  // Cancel pending asynchronous operations.
+  ASIO_DECL void cancel(implementation_type& impl);
+
+protected:
+  // Helper function to start an asynchronous resolve operation.
+  ASIO_DECL void start_resolve_op(resolve_op* op);
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+  // Helper class to perform exception-safe cleanup of addrinfo objects.
+  class auto_addrinfo
+    : private asio::detail::noncopyable
+  {
+  public:
+    explicit auto_addrinfo(asio::detail::addrinfo_type* ai)
+      : ai_(ai)
+    {
+    }
+
+    ~auto_addrinfo()
+    {
+      if (ai_)
+        socket_ops::freeaddrinfo(ai_);
+    }
+
+    operator asio::detail::addrinfo_type*()
+    {
+      return ai_;
+    }
+
+  private:
+    asio::detail::addrinfo_type* ai_;
+  };
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+  // Helper class to run the work io_context in a thread.
+  class work_io_context_runner;
+
+  // Start the work thread if it's not already running.
+  ASIO_DECL void start_work_thread();
+
+  // The io_context implementation used to post completions.
+  io_context_impl& io_context_impl_;
+
+private:
+  // Mutex to protect access to internal data.
+  asio::detail::mutex mutex_;
+
+  // Private io_context used for performing asynchronous host resolution.
+  asio::detail::scoped_ptr<asio::io_context> work_io_context_;
+
+  // The work io_context implementation used to post completions.
+  io_context_impl& work_io_context_impl_;
+
+  // Work for the private io_context to perform.
+  asio::executor_work_guard<
+      asio::io_context::executor_type> work_;
+
+  // Thread used for running the work io_context's run loop.
+  asio::detail::scoped_ptr<asio::detail::thread> work_thread_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/resolver_service_base.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_RESOLVER_SERVICE_BASE_HPP
diff --git a/subprojects/asio/include/asio/detail/scheduler.hpp b/subprojects/asio/include/asio/detail/scheduler.hpp
new file mode 100644
index 000000000..10c29b7ed
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/scheduler.hpp
@@ -0,0 +1,213 @@
+//
+// detail/scheduler.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SCHEDULER_HPP
+#define ASIO_DETAIL_SCHEDULER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/error_code.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/detail/atomic_count.hpp"
+#include "asio/detail/conditionally_enabled_event.hpp"
+#include "asio/detail/conditionally_enabled_mutex.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/reactor_fwd.hpp"
+#include "asio/detail/scheduler_operation.hpp"
+#include "asio/detail/thread_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct scheduler_thread_info;
+
+class scheduler
+  : public execution_context_service_base<scheduler>,
+    public thread_context
+{
+public:
+  typedef scheduler_operation operation;
+
+  // Constructor. Specifies the number of concurrent threads that are likely to
+  // run the scheduler. If set to 1 certain optimisation are performed.
+  ASIO_DECL scheduler(asio::execution_context& ctx,
+      int concurrency_hint = 0);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Initialise the task, if required.
+  ASIO_DECL void init_task();
+
+  // Run the event loop until interrupted or no more work.
+  ASIO_DECL std::size_t run(asio::error_code& ec);
+
+  // Run until interrupted or one operation is performed.
+  ASIO_DECL std::size_t run_one(asio::error_code& ec);
+
+  // Run until timeout, interrupted, or one operation is performed.
+  ASIO_DECL std::size_t wait_one(
+      long usec, asio::error_code& ec);
+
+  // Poll for operations without blocking.
+  ASIO_DECL std::size_t poll(asio::error_code& ec);
+
+  // Poll for one operation without blocking.
+  ASIO_DECL std::size_t poll_one(asio::error_code& ec);
+
+  // Interrupt the event processing loop.
+  ASIO_DECL void stop();
+
+  // Determine whether the scheduler is stopped.
+  ASIO_DECL bool stopped() const;
+
+  // Restart in preparation for a subsequent run invocation.
+  ASIO_DECL void restart();
+
+  // Notify that some work has started.
+  void work_started()
+  {
+    ++outstanding_work_;
+  }
+
+  // Used to compensate for a forthcoming work_finished call. Must be called
+  // from within a scheduler-owned thread.
+  ASIO_DECL void compensating_work_started();
+
+  // Notify that some work has finished.
+  void work_finished()
+  {
+    if (--outstanding_work_ == 0)
+      stop();
+  }
+
+  // Return whether a handler can be dispatched immediately.
+  bool can_dispatch()
+  {
+    return thread_call_stack::contains(this) != 0;
+  }
+
+  // Request invocation of the given operation and return immediately. Assumes
+  // that work_started() has not yet been called for the operation.
+  ASIO_DECL void post_immediate_completion(
+      operation* op, bool is_continuation);
+
+  // Request invocation of the given operation and return immediately. Assumes
+  // that work_started() was previously called for the operation.
+  ASIO_DECL void post_deferred_completion(operation* op);
+
+  // Request invocation of the given operations and return immediately. Assumes
+  // that work_started() was previously called for each operation.
+  ASIO_DECL void post_deferred_completions(op_queue<operation>& ops);
+
+  // Enqueue the given operation following a failed attempt to dispatch the
+  // operation for immediate invocation.
+  ASIO_DECL void do_dispatch(operation* op);
+
+  // Process unfinished operations as part of a shutdownoperation. Assumes that
+  // work_started() was previously called for the operations.
+  ASIO_DECL void abandon_operations(op_queue<operation>& ops);
+
+  // Get the concurrency hint that was used to initialise the scheduler.
+  int concurrency_hint() const
+  {
+    return concurrency_hint_;
+  }
+
+private:
+  // The mutex type used by this scheduler.
+  typedef conditionally_enabled_mutex mutex;
+
+  // The event type used by this scheduler.
+  typedef conditionally_enabled_event event;
+
+  // Structure containing thread-specific data.
+  typedef scheduler_thread_info thread_info;
+
+  // Run at most one operation. May block.
+  ASIO_DECL std::size_t do_run_one(mutex::scoped_lock& lock,
+      thread_info& this_thread, const asio::error_code& ec);
+
+  // Run at most one operation with a timeout. May block.
+  ASIO_DECL std::size_t do_wait_one(mutex::scoped_lock& lock,
+      thread_info& this_thread, long usec, const asio::error_code& ec);
+
+  // Poll for at most one operation.
+  ASIO_DECL std::size_t do_poll_one(mutex::scoped_lock& lock,
+      thread_info& this_thread, const asio::error_code& ec);
+
+  // Stop the task and all idle threads.
+  ASIO_DECL void stop_all_threads(mutex::scoped_lock& lock);
+
+  // Wake a single idle thread, or the task, and always unlock the mutex.
+  ASIO_DECL void wake_one_thread_and_unlock(
+      mutex::scoped_lock& lock);
+
+  // Helper class to perform task-related operations on block exit.
+  struct task_cleanup;
+  friend struct task_cleanup;
+
+  // Helper class to call work-related operations on block exit.
+  struct work_cleanup;
+  friend struct work_cleanup;
+
+  // Whether to optimise for single-threaded use cases.
+  const bool one_thread_;
+
+  // Mutex to protect access to internal data.
+  mutable mutex mutex_;
+
+  // Event to wake up blocked threads.
+  event wakeup_event_;
+
+  // The task to be run by this service.
+  reactor* task_;
+
+  // Operation object to represent the position of the task in the queue.
+  struct task_operation : operation
+  {
+    task_operation() : operation(0) {}
+  } task_operation_;
+
+  // Whether the task has been interrupted.
+  bool task_interrupted_;
+
+  // The count of unfinished work.
+  atomic_count outstanding_work_;
+
+  // The queue of handlers that are ready to be delivered.
+  op_queue<operation> op_queue_;
+
+  // Flag to indicate that the dispatcher has been stopped.
+  bool stopped_;
+
+  // Flag to indicate that the dispatcher has been shut down.
+  bool shutdown_;
+
+  // The concurrency hint used to initialise the scheduler.
+  const int concurrency_hint_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/scheduler.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_SCHEDULER_HPP
diff --git a/subprojects/asio/include/asio/detail/scheduler_operation.hpp b/subprojects/asio/include/asio/detail/scheduler_operation.hpp
new file mode 100644
index 000000000..1c2ce02ec
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/scheduler_operation.hpp
@@ -0,0 +1,78 @@
+//
+// detail/scheduler_operation.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SCHEDULER_OPERATION_HPP
+#define ASIO_DETAIL_SCHEDULER_OPERATION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/error_code.hpp"
+#include "asio/detail/handler_tracking.hpp"
+#include "asio/detail/op_queue.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class scheduler;
+
+// Base class for all operations. A function pointer is used instead of virtual
+// functions to avoid the associated overhead.
+class scheduler_operation ASIO_INHERIT_TRACKED_HANDLER
+{
+public:
+  typedef scheduler_operation operation_type;
+
+  void complete(void* owner, const asio::error_code& ec,
+      std::size_t bytes_transferred)
+  {
+    func_(owner, this, ec, bytes_transferred);
+  }
+
+  void destroy()
+  {
+    func_(0, this, asio::error_code(), 0);
+  }
+
+protected:
+  typedef void (*func_type)(void*,
+      scheduler_operation*,
+      const asio::error_code&, std::size_t);
+
+  scheduler_operation(func_type func)
+    : next_(0),
+      func_(func),
+      task_result_(0)
+  {
+  }
+
+  // Prevents deletion through this type.
+  ~scheduler_operation()
+  {
+  }
+
+private:
+  friend class op_queue_access;
+  scheduler_operation* next_;
+  func_type func_;
+protected:
+  friend class scheduler;
+  unsigned int task_result_; // Passed into bytes transferred.
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SCHEDULER_OPERATION_HPP
diff --git a/subprojects/asio/include/asio/detail/scheduler_thread_info.hpp b/subprojects/asio/include/asio/detail/scheduler_thread_info.hpp
new file mode 100644
index 000000000..2ffe013bc
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/scheduler_thread_info.hpp
@@ -0,0 +1,40 @@
+//
+// detail/scheduler_thread_info.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SCHEDULER_THREAD_INFO_HPP
+#define ASIO_DETAIL_SCHEDULER_THREAD_INFO_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/thread_info_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class scheduler;
+class scheduler_operation;
+
+struct scheduler_thread_info : public thread_info_base
+{
+  op_queue<scheduler_operation> private_op_queue;
+  long private_outstanding_work;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SCHEDULER_THREAD_INFO_HPP
diff --git a/subprojects/asio/include/asio/detail/scoped_lock.hpp b/subprojects/asio/include/asio/detail/scoped_lock.hpp
new file mode 100644
index 000000000..6cbce3814
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/scoped_lock.hpp
@@ -0,0 +1,101 @@
+//
+// detail/scoped_lock.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SCOPED_LOCK_HPP
+#define ASIO_DETAIL_SCOPED_LOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper class to lock and unlock a mutex automatically.
+template <typename Mutex>
+class scoped_lock
+  : private noncopyable
+{
+public:
+  // Tag type used to distinguish constructors.
+  enum adopt_lock_t { adopt_lock };
+
+  // Constructor adopts a lock that is already held.
+  scoped_lock(Mutex& m, adopt_lock_t)
+    : mutex_(m),
+      locked_(true)
+  {
+  }
+
+  // Constructor acquires the lock.
+  explicit scoped_lock(Mutex& m)
+    : mutex_(m)
+  {
+    mutex_.lock();
+    locked_ = true;
+  }
+
+  // Destructor releases the lock.
+  ~scoped_lock()
+  {
+    if (locked_)
+      mutex_.unlock();
+  }
+
+  // Explicitly acquire the lock.
+  void lock()
+  {
+    if (!locked_)
+    {
+      mutex_.lock();
+      locked_ = true;
+    }
+  }
+
+  // Explicitly release the lock.
+  void unlock()
+  {
+    if (locked_)
+    {
+      mutex_.unlock();
+      locked_ = false;
+    }
+  }
+
+  // Test whether the lock is held.
+  bool locked() const
+  {
+    return locked_;
+  }
+
+  // Get the underlying mutex.
+  Mutex& mutex()
+  {
+    return mutex_;
+  }
+
+private:
+  // The underlying mutex.
+  Mutex& mutex_;
+
+  // Whether the mutex is currently locked or unlocked.
+  bool locked_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SCOPED_LOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/scoped_ptr.hpp b/subprojects/asio/include/asio/detail/scoped_ptr.hpp
new file mode 100644
index 000000000..3449c53b7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/scoped_ptr.hpp
@@ -0,0 +1,87 @@
+//
+// detail/scoped_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SCOPED_PTR_HPP
+#define ASIO_DETAIL_SCOPED_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+class scoped_ptr
+{
+public:
+  // Constructor.
+  explicit scoped_ptr(T* p = 0)
+    : p_(p)
+  {
+  }
+
+  // Destructor.
+  ~scoped_ptr()
+  {
+    delete p_;
+  }
+
+  // Access.
+  T* get()
+  {
+    return p_;
+  }
+
+  // Access.
+  T* operator->()
+  {
+    return p_;
+  }
+
+  // Dereference.
+  T& operator*()
+  {
+    return *p_;
+  }
+
+  // Reset pointer.
+  void reset(T* p = 0)
+  {
+    delete p_;
+    p_ = p;
+  }
+
+  // Release ownership of the pointer.
+  T* release()
+  {
+    T* tmp = p_;
+    p_ = 0;
+    return tmp;
+  }
+
+private:
+  // Disallow copying and assignment.
+  scoped_ptr(const scoped_ptr&);
+  scoped_ptr& operator=(const scoped_ptr&);
+
+  T* p_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SCOPED_PTR_HPP
diff --git a/subprojects/asio/include/asio/detail/select_interrupter.hpp b/subprojects/asio/include/asio/detail/select_interrupter.hpp
new file mode 100644
index 000000000..1a0759918
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/select_interrupter.hpp
@@ -0,0 +1,46 @@
+//
+// detail/select_interrupter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SELECT_INTERRUPTER_HPP
+#define ASIO_DETAIL_SELECT_INTERRUPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__) || defined(__SYMBIAN32__)
+# include "asio/detail/socket_select_interrupter.hpp"
+#elif defined(ASIO_HAS_EVENTFD)
+# include "asio/detail/eventfd_select_interrupter.hpp"
+#else
+# include "asio/detail/pipe_select_interrupter.hpp"
+#endif
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__) || defined(__SYMBIAN32__)
+typedef socket_select_interrupter select_interrupter;
+#elif defined(ASIO_HAS_EVENTFD)
+typedef eventfd_select_interrupter select_interrupter;
+#else
+typedef pipe_select_interrupter select_interrupter;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_SELECT_INTERRUPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/select_reactor.hpp b/subprojects/asio/include/asio/detail/select_reactor.hpp
new file mode 100644
index 000000000..099654927
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/select_reactor.hpp
@@ -0,0 +1,238 @@
+//
+// detail/select_reactor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SELECT_REACTOR_HPP
+#define ASIO_DETAIL_SELECT_REACTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP) \
+  || (!defined(ASIO_HAS_DEV_POLL) \
+      && !defined(ASIO_HAS_EPOLL) \
+      && !defined(ASIO_HAS_KQUEUE) \
+      && !defined(ASIO_WINDOWS_RUNTIME))
+
+#include <cstddef>
+#include "asio/detail/fd_set_adapter.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/reactor_op_queue.hpp"
+#include "asio/detail/select_interrupter.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+#include "asio/detail/timer_queue_set.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/execution_context.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+# include "asio/detail/thread.hpp"
+#endif // defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class select_reactor
+  : public execution_context_service_base<select_reactor>
+{
+public:
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  enum op_types { read_op = 0, write_op = 1, except_op = 2,
+    max_select_ops = 3, connect_op = 3, max_ops = 4 };
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  enum op_types { read_op = 0, write_op = 1, except_op = 2,
+    max_select_ops = 3, connect_op = 1, max_ops = 3 };
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+  // Per-descriptor data.
+  struct per_descriptor_data
+  {
+  };
+
+  // Constructor.
+  ASIO_DECL select_reactor(asio::execution_context& ctx);
+
+  // Destructor.
+  ASIO_DECL ~select_reactor();
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Recreate internal descriptors following a fork.
+  ASIO_DECL void notify_fork(
+      asio::execution_context::fork_event fork_ev);
+
+  // Initialise the task, but only if the reactor is not in its own thread.
+  ASIO_DECL void init_task();
+
+  // Register a socket with the reactor. Returns 0 on success, system error
+  // code on failure.
+  ASIO_DECL int register_descriptor(socket_type, per_descriptor_data&);
+
+  // Register a descriptor with an associated single operation. Returns 0 on
+  // success, system error code on failure.
+  ASIO_DECL int register_internal_descriptor(
+      int op_type, socket_type descriptor,
+      per_descriptor_data& descriptor_data, reactor_op* op);
+
+  // Post a reactor operation for immediate completion.
+  void post_immediate_completion(reactor_op* op, bool is_continuation)
+  {
+    scheduler_.post_immediate_completion(op, is_continuation);
+  }
+
+  // Start a new operation. The reactor operation will be performed when the
+  // given descriptor is flagged as ready, or an error has occurred.
+  ASIO_DECL void start_op(int op_type, socket_type descriptor,
+      per_descriptor_data&, reactor_op* op, bool is_continuation, bool);
+
+  // Cancel all operations associated with the given descriptor. The
+  // handlers associated with the descriptor will be invoked with the
+  // operation_aborted error.
+  ASIO_DECL void cancel_ops(socket_type descriptor, per_descriptor_data&);
+
+  // Cancel any operations that are running against the descriptor and remove
+  // its registration from the reactor. The reactor resources associated with
+  // the descriptor must be released by calling cleanup_descriptor_data.
+  ASIO_DECL void deregister_descriptor(socket_type descriptor,
+      per_descriptor_data&, bool closing);
+
+  // Remove the descriptor's registration from the reactor. The reactor
+  // resources associated with the descriptor must be released by calling
+  // cleanup_descriptor_data.
+  ASIO_DECL void deregister_internal_descriptor(
+      socket_type descriptor, per_descriptor_data&);
+
+  // Perform any post-deregistration cleanup tasks associated with the
+  // descriptor data.
+  ASIO_DECL void cleanup_descriptor_data(per_descriptor_data&);
+
+  // Move descriptor registration from one descriptor_data object to another.
+  ASIO_DECL void move_descriptor(socket_type descriptor,
+      per_descriptor_data& target_descriptor_data,
+      per_descriptor_data& source_descriptor_data);
+
+  // Add a new timer queue to the reactor.
+  template <typename Time_Traits>
+  void add_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Remove a timer queue from the reactor.
+  template <typename Time_Traits>
+  void remove_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Schedule a new operation in the given timer queue to expire at the
+  // specified absolute time.
+  template <typename Time_Traits>
+  void schedule_timer(timer_queue<Time_Traits>& queue,
+      const typename Time_Traits::time_type& time,
+      typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
+
+  // Cancel the timer operations associated with the given token. Returns the
+  // number of operations that have been posted or dispatched.
+  template <typename Time_Traits>
+  std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& timer,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
+
+  // Move the timer operations associated with the given timer.
+  template <typename Time_Traits>
+  void move_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& target,
+      typename timer_queue<Time_Traits>::per_timer_data& source);
+
+  // Run select once until interrupted or events are ready to be dispatched.
+  ASIO_DECL void run(long usec, op_queue<operation>& ops);
+
+  // Interrupt the select loop.
+  ASIO_DECL void interrupt();
+
+private:
+#if defined(ASIO_HAS_IOCP)
+  // Run the select loop in the thread.
+  ASIO_DECL void run_thread();
+#endif // defined(ASIO_HAS_IOCP)
+
+  // Helper function to add a new timer queue.
+  ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
+
+  // Helper function to remove a timer queue.
+  ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
+
+  // Get the timeout value for the select call.
+  ASIO_DECL timeval* get_timeout(long usec, timeval& tv);
+
+  // Cancel all operations associated with the given descriptor. This function
+  // does not acquire the select_reactor's mutex.
+  ASIO_DECL void cancel_ops_unlocked(socket_type descriptor,
+      const asio::error_code& ec);
+
+  // The scheduler implementation used to post completions.
+# if defined(ASIO_HAS_IOCP)
+  typedef class win_iocp_io_context scheduler_type;
+# else // defined(ASIO_HAS_IOCP)
+  typedef class scheduler scheduler_type;
+# endif // defined(ASIO_HAS_IOCP)
+  scheduler_type& scheduler_;
+
+  // Mutex to protect access to internal data.
+  asio::detail::mutex mutex_;
+
+  // The interrupter is used to break a blocking select call.
+  select_interrupter interrupter_;
+
+  // The queues of read, write and except operations.
+  reactor_op_queue<socket_type> op_queue_[max_ops];
+
+  // The file descriptor sets to be passed to the select system call.
+  fd_set_adapter fd_sets_[max_select_ops];
+
+  // The timer queues.
+  timer_queue_set timer_queues_;
+
+#if defined(ASIO_HAS_IOCP)
+  // Helper class to run the reactor loop in a thread.
+  class thread_function;
+  friend class thread_function;
+
+  // Does the reactor loop thread need to stop.
+  bool stop_thread_;
+
+  // The thread that is running the reactor loop.
+  asio::detail::thread* thread_;
+#endif // defined(ASIO_HAS_IOCP)
+
+  // Whether the service has been shut down.
+  bool shutdown_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/select_reactor.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/select_reactor.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_IOCP)
+       //   || (!defined(ASIO_HAS_DEV_POLL)
+       //       && !defined(ASIO_HAS_EPOLL)
+       //       && !defined(ASIO_HAS_KQUEUE)
+       //       && !defined(ASIO_WINDOWS_RUNTIME))
+
+#endif // ASIO_DETAIL_SELECT_REACTOR_HPP
diff --git a/subprojects/asio/include/asio/detail/service_registry.hpp b/subprojects/asio/include/asio/detail/service_registry.hpp
new file mode 100644
index 000000000..cda63072f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/service_registry.hpp
@@ -0,0 +1,164 @@
+//
+// detail/service_registry.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SERVICE_REGISTRY_HPP
+#define ASIO_DETAIL_SERVICE_REGISTRY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <typeinfo>
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class io_context;
+
+namespace detail {
+
+template <typename T>
+class typeid_wrapper {};
+
+class service_registry
+  : private noncopyable
+{
+public:
+  // Constructor.
+  ASIO_DECL service_registry(execution_context& owner);
+
+  // Destructor.
+  ASIO_DECL ~service_registry();
+
+  // Shutdown all services.
+  ASIO_DECL void shutdown_services();
+
+  // Destroy all services.
+  ASIO_DECL void destroy_services();
+
+  // Notify all services of a fork event.
+  ASIO_DECL void notify_fork(execution_context::fork_event fork_ev);
+
+  // Get the service object corresponding to the specified service type. Will
+  // create a new service object automatically if no such object already
+  // exists. Ownership of the service object is not transferred to the caller.
+  template <typename Service>
+  Service& use_service();
+
+  // Get the service object corresponding to the specified service type. Will
+  // create a new service object automatically if no such object already
+  // exists. Ownership of the service object is not transferred to the caller.
+  // This overload is used for backwards compatibility with services that
+  // inherit from io_context::service.
+  template <typename Service>
+  Service& use_service(io_context& owner);
+
+  // Add a service object. Throws on error, in which case ownership of the
+  // object is retained by the caller.
+  template <typename Service>
+  void add_service(Service* new_service);
+
+  // Check whether a service object of the specified type already exists.
+  template <typename Service>
+  bool has_service() const;
+
+private:
+  // Initalise a service's key when the key_type typedef is not available.
+  template <typename Service>
+  static void init_key(execution_context::service::key& key, ...);
+
+#if !defined(ASIO_NO_TYPEID)
+  // Initalise a service's key when the key_type typedef is available.
+  template <typename Service>
+  static void init_key(execution_context::service::key& key,
+      typename enable_if<
+        is_base_of<typename Service::key_type, Service>::value>::type*);
+#endif // !defined(ASIO_NO_TYPEID)
+
+  // Initialise a service's key based on its id.
+  ASIO_DECL static void init_key_from_id(
+      execution_context::service::key& key,
+      const execution_context::id& id);
+
+#if !defined(ASIO_NO_TYPEID)
+  // Initialise a service's key based on its id.
+  template <typename Service>
+  static void init_key_from_id(execution_context::service::key& key,
+      const service_id<Service>& /*id*/);
+#endif // !defined(ASIO_NO_TYPEID)
+
+  // Check if a service matches the given id.
+  ASIO_DECL static bool keys_match(
+      const execution_context::service::key& key1,
+      const execution_context::service::key& key2);
+
+  // The type of a factory function used for creating a service instance.
+  typedef execution_context::service*(*factory_type)(void*);
+
+  // Factory function for creating a service instance.
+  template <typename Service, typename Owner>
+  static execution_context::service* create(void* owner);
+
+  // Destroy a service instance.
+  ASIO_DECL static void destroy(execution_context::service* service);
+
+  // Helper class to manage service pointers.
+  struct auto_service_ptr;
+  friend struct auto_service_ptr;
+  struct auto_service_ptr
+  {
+    execution_context::service* ptr_;
+    ~auto_service_ptr() { destroy(ptr_); }
+  };
+
+  // Get the service object corresponding to the specified service key. Will
+  // create a new service object automatically if no such object already
+  // exists. Ownership of the service object is not transferred to the caller.
+  ASIO_DECL execution_context::service* do_use_service(
+      const execution_context::service::key& key,
+      factory_type factory, void* owner);
+
+  // Add a service object. Throws on error, in which case ownership of the
+  // object is retained by the caller.
+  ASIO_DECL void do_add_service(
+      const execution_context::service::key& key,
+      execution_context::service* new_service);
+
+  // Check whether a service object with the specified key already exists.
+  ASIO_DECL bool do_has_service(
+      const execution_context::service::key& key) const;
+
+  // Mutex to protect access to internal data.
+  mutable asio::detail::mutex mutex_;
+
+  // The owner of this service registry and the services it contains.
+  execution_context& owner_;
+
+  // The first service in the list of contained services.
+  execution_context::service* first_service_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/service_registry.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/service_registry.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_SERVICE_REGISTRY_HPP
diff --git a/subprojects/asio/include/asio/detail/signal_blocker.hpp b/subprojects/asio/include/asio/detail/signal_blocker.hpp
new file mode 100644
index 000000000..b68429577
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/signal_blocker.hpp
@@ -0,0 +1,44 @@
+//
+// detail/signal_blocker.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SIGNAL_BLOCKER_HPP
+#define ASIO_DETAIL_SIGNAL_BLOCKER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS) || defined(ASIO_WINDOWS) \
+  || defined(ASIO_WINDOWS_RUNTIME) \
+  || defined(__CYGWIN__) || defined(__SYMBIAN32__)
+# include "asio/detail/null_signal_blocker.hpp"
+#elif defined(ASIO_HAS_PTHREADS)
+# include "asio/detail/posix_signal_blocker.hpp"
+#else
+# error Only Windows and POSIX are supported!
+#endif
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS) || defined(ASIO_WINDOWS) \
+  || defined(ASIO_WINDOWS_RUNTIME) \
+  || defined(__CYGWIN__) || defined(__SYMBIAN32__)
+typedef null_signal_blocker signal_blocker;
+#elif defined(ASIO_HAS_PTHREADS)
+typedef posix_signal_blocker signal_blocker;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_SIGNAL_BLOCKER_HPP
diff --git a/subprojects/asio/include/asio/detail/signal_handler.hpp b/subprojects/asio/include/asio/detail/signal_handler.hpp
new file mode 100644
index 000000000..d1c99105a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/signal_handler.hpp
@@ -0,0 +1,86 @@
+//
+// detail/signal_handler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SIGNAL_HANDLER_HPP
+#define ASIO_DETAIL_SIGNAL_HANDLER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_work.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/signal_op.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class signal_handler : public signal_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(signal_handler);
+
+  signal_handler(Handler& h)
+    : signal_op(&signal_handler::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(h))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    signal_handler* h(static_cast<signal_handler*>(base));
+    ptr p = { asio::detail::addressof(h->handler_), h, h };
+    handler_work<Handler> w(h->handler_);
+
+    ASIO_HANDLER_COMPLETION((*h));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, int>
+      handler(h->handler_, h->ec_, h->signal_number_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SIGNAL_HANDLER_HPP
diff --git a/subprojects/asio/include/asio/detail/signal_init.hpp b/subprojects/asio/include/asio/detail/signal_init.hpp
new file mode 100644
index 000000000..814ff5196
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/signal_init.hpp
@@ -0,0 +1,47 @@
+//
+// detail/signal_init.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SIGNAL_INIT_HPP
+#define ASIO_DETAIL_SIGNAL_INIT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include <csignal>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <int Signal = SIGPIPE>
+class signal_init
+{
+public:
+  // Constructor.
+  signal_init()
+  {
+    std::signal(Signal, SIG_IGN);
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_SIGNAL_INIT_HPP
diff --git a/subprojects/asio/include/asio/detail/signal_op.hpp b/subprojects/asio/include/asio/detail/signal_op.hpp
new file mode 100644
index 000000000..c4e364c14
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/signal_op.hpp
@@ -0,0 +1,49 @@
+//
+// detail/signal_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SIGNAL_OP_HPP
+#define ASIO_DETAIL_SIGNAL_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class signal_op
+  : public operation
+{
+public:
+  // The error code to be passed to the completion handler.
+  asio::error_code ec_;
+
+  // The signal number to be passed to the completion handler.
+  int signal_number_;
+
+protected:
+  signal_op(func_type func)
+    : operation(func),
+      signal_number_(0)
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SIGNAL_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/signal_set_service.hpp b/subprojects/asio/include/asio/detail/signal_set_service.hpp
new file mode 100644
index 000000000..a18ab7093
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/signal_set_service.hpp
@@ -0,0 +1,217 @@
+//
+// detail/signal_set_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SIGNAL_SET_SERVICE_HPP
+#define ASIO_DETAIL_SIGNAL_SET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cstddef>
+#include <signal.h>
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/signal_handler.hpp"
+#include "asio/detail/signal_op.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+# include "asio/detail/reactor.hpp"
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(NSIG) && (NSIG > 0)
+enum { max_signal_number = NSIG };
+#else
+enum { max_signal_number = 128 };
+#endif
+
+extern ASIO_DECL struct signal_state* get_signal_state();
+
+extern "C" ASIO_DECL void asio_signal_handler(int signal_number);
+
+class signal_set_service :
+  public service_base<signal_set_service>
+{
+public:
+  // Type used for tracking an individual signal registration.
+  class registration
+  {
+  public:
+    // Default constructor.
+    registration()
+      : signal_number_(0),
+        queue_(0),
+        undelivered_(0),
+        next_in_table_(0),
+        prev_in_table_(0),
+        next_in_set_(0)
+    {
+    }
+
+  private:
+    // Only this service will have access to the internal values.
+    friend class signal_set_service;
+
+    // The signal number that is registered.
+    int signal_number_;
+
+    // The waiting signal handlers.
+    op_queue<signal_op>* queue_;
+
+    // The number of undelivered signals.
+    std::size_t undelivered_;
+
+    // Pointers to adjacent registrations in the registrations_ table.
+    registration* next_in_table_;
+    registration* prev_in_table_;
+
+    // Link to next registration in the signal set.
+    registration* next_in_set_;
+  };
+
+  // The implementation type of the signal_set.
+  class implementation_type
+  {
+  public:
+    // Default constructor.
+    implementation_type()
+      : signals_(0)
+    {
+    }
+
+  private:
+    // Only this service will have access to the internal values.
+    friend class signal_set_service;
+
+    // The pending signal handlers.
+    op_queue<signal_op> queue_;
+
+    // Linked list of registered signals.
+    registration* signals_;
+  };
+
+  // Constructor.
+  ASIO_DECL signal_set_service(asio::io_context& io_context);
+
+  // Destructor.
+  ASIO_DECL ~signal_set_service();
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Perform fork-related housekeeping.
+  ASIO_DECL void notify_fork(
+      asio::io_context::fork_event fork_ev);
+
+  // Construct a new signal_set implementation.
+  ASIO_DECL void construct(implementation_type& impl);
+
+  // Destroy a signal_set implementation.
+  ASIO_DECL void destroy(implementation_type& impl);
+
+  // Add a signal to a signal_set.
+  ASIO_DECL asio::error_code add(implementation_type& impl,
+      int signal_number, asio::error_code& ec);
+
+  // Remove a signal to a signal_set.
+  ASIO_DECL asio::error_code remove(implementation_type& impl,
+      int signal_number, asio::error_code& ec);
+
+  // Remove all signals from a signal_set.
+  ASIO_DECL asio::error_code clear(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Cancel all operations associated with the signal set.
+  ASIO_DECL asio::error_code cancel(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Start an asynchronous operation to wait for a signal to be delivered.
+  template <typename Handler>
+  void async_wait(implementation_type& impl, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef signal_handler<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((io_context_.context(),
+          *p.p, "signal_set", &impl, 0, "async_wait"));
+
+    start_wait_op(impl, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Deliver notification that a particular signal occurred.
+  ASIO_DECL static void deliver_signal(int signal_number);
+
+private:
+  // Helper function to add a service to the global signal state.
+  ASIO_DECL static void add_service(signal_set_service* service);
+
+  // Helper function to remove a service from the global signal state.
+  ASIO_DECL static void remove_service(signal_set_service* service);
+
+  // Helper function to create the pipe descriptors.
+  ASIO_DECL static void open_descriptors();
+
+  // Helper function to close the pipe descriptors.
+  ASIO_DECL static void close_descriptors();
+
+  // Helper function to start a wait operation.
+  ASIO_DECL void start_wait_op(implementation_type& impl, signal_op* op);
+
+  // The io_context instance used for dispatching handlers.
+  io_context_impl& io_context_;
+
+#if !defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_RUNTIME) \
+  && !defined(__CYGWIN__)
+  // The type used for registering for pipe reactor notifications.
+  class pipe_read_op;
+
+  // The reactor used for waiting for pipe readiness.
+  reactor& reactor_;
+
+  // The per-descriptor reactor data used for the pipe.
+  reactor::per_descriptor_data reactor_data_;
+#endif // !defined(ASIO_WINDOWS)
+       //   && !defined(ASIO_WINDOWS_RUNTIME)
+       //   && !defined(__CYGWIN__)
+
+  // A mapping from signal number to the registered signal sets.
+  registration* registrations_[max_signal_number];
+
+  // Pointers to adjacent services in linked list.
+  signal_set_service* next_;
+  signal_set_service* prev_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/signal_set_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_SIGNAL_SET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/socket_holder.hpp b/subprojects/asio/include/asio/detail/socket_holder.hpp
new file mode 100644
index 000000000..99b081f71
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/socket_holder.hpp
@@ -0,0 +1,98 @@
+//
+// detail/socket_holder.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SOCKET_HOLDER_HPP
+#define ASIO_DETAIL_SOCKET_HOLDER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Implement the resource acquisition is initialisation idiom for sockets.
+class socket_holder
+  : private noncopyable
+{
+public:
+  // Construct as an uninitialised socket.
+  socket_holder()
+    : socket_(invalid_socket)
+  {
+  }
+
+  // Construct to take ownership of the specified socket.
+  explicit socket_holder(socket_type s)
+    : socket_(s)
+  {
+  }
+
+  // Destructor.
+  ~socket_holder()
+  {
+    if (socket_ != invalid_socket)
+    {
+      asio::error_code ec;
+      socket_ops::state_type state = 0;
+      socket_ops::close(socket_, state, true, ec);
+    }
+  }
+
+  // Get the underlying socket.
+  socket_type get() const
+  {
+    return socket_;
+  }
+
+  // Reset to an uninitialised socket.
+  void reset()
+  {
+    if (socket_ != invalid_socket)
+    {
+      asio::error_code ec;
+      socket_ops::state_type state = 0;
+      socket_ops::close(socket_, state, true, ec);
+      socket_ = invalid_socket;
+    }
+  }
+
+  // Reset to take ownership of the specified socket.
+  void reset(socket_type s)
+  {
+    reset();
+    socket_ = s;
+  }
+
+  // Release ownership of the socket.
+  socket_type release()
+  {
+    socket_type tmp = socket_;
+    socket_ = invalid_socket;
+    return tmp;
+  }
+
+private:
+  // The underlying socket.
+  socket_type socket_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SOCKET_HOLDER_HPP
diff --git a/subprojects/asio/include/asio/detail/socket_ops.hpp b/subprojects/asio/include/asio/detail/socket_ops.hpp
new file mode 100644
index 000000000..815b0d1c8
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/socket_ops.hpp
@@ -0,0 +1,337 @@
+//
+// detail/socket_ops.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SOCKET_OPS_HPP
+#define ASIO_DETAIL_SOCKET_OPS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/error_code.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace socket_ops {
+
+// Socket state bits.
+enum
+{
+  // The user wants a non-blocking socket.
+  user_set_non_blocking = 1,
+
+  // The socket has been set non-blocking.
+  internal_non_blocking = 2,
+
+  // Helper "state" used to determine whether the socket is non-blocking.
+  non_blocking = user_set_non_blocking | internal_non_blocking,
+
+  // User wants connection_aborted errors, which are disabled by default.
+  enable_connection_aborted = 4,
+
+  // The user set the linger option. Needs to be checked when closing.
+  user_set_linger = 8,
+
+  // The socket is stream-oriented.
+  stream_oriented = 16,
+
+  // The socket is datagram-oriented.
+  datagram_oriented = 32,
+
+  // The socket may have been dup()-ed.
+  possible_dup = 64
+};
+
+typedef unsigned char state_type;
+
+struct noop_deleter { void operator()(void*) {} };
+typedef shared_ptr<void> shared_cancel_token_type;
+typedef weak_ptr<void> weak_cancel_token_type;
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+ASIO_DECL socket_type accept(socket_type s, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec);
+
+ASIO_DECL socket_type sync_accept(socket_type s,
+    state_type state, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec);
+
+#if defined(ASIO_HAS_IOCP)
+
+ASIO_DECL void complete_iocp_accept(socket_type s,
+    void* output_buffer, DWORD address_length,
+    socket_addr_type* addr, std::size_t* addrlen,
+    socket_type new_socket, asio::error_code& ec);
+
+#else // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL bool non_blocking_accept(socket_type s,
+    state_type state, socket_addr_type* addr, std::size_t* addrlen,
+    asio::error_code& ec, socket_type& new_socket);
+
+#endif // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL int bind(socket_type s, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec);
+
+ASIO_DECL int close(socket_type s, state_type& state,
+    bool destruction, asio::error_code& ec);
+
+ASIO_DECL bool set_user_non_blocking(socket_type s,
+    state_type& state, bool value, asio::error_code& ec);
+
+ASIO_DECL bool set_internal_non_blocking(socket_type s,
+    state_type& state, bool value, asio::error_code& ec);
+
+ASIO_DECL int shutdown(socket_type s,
+    int what, asio::error_code& ec);
+
+ASIO_DECL int connect(socket_type s, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec);
+
+ASIO_DECL void sync_connect(socket_type s, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec);
+
+#if defined(ASIO_HAS_IOCP)
+
+ASIO_DECL void complete_iocp_connect(socket_type s,
+    asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL bool non_blocking_connect(socket_type s,
+    asio::error_code& ec);
+
+ASIO_DECL int socketpair(int af, int type, int protocol,
+    socket_type sv[2], asio::error_code& ec);
+
+ASIO_DECL bool sockatmark(socket_type s, asio::error_code& ec);
+
+ASIO_DECL size_t available(socket_type s, asio::error_code& ec);
+
+ASIO_DECL int listen(socket_type s,
+    int backlog, asio::error_code& ec);
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+typedef WSABUF buf;
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+typedef iovec buf;
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+ASIO_DECL void init_buf(buf& b, void* data, size_t size);
+
+ASIO_DECL void init_buf(buf& b, const void* data, size_t size);
+
+ASIO_DECL signed_size_type recv(socket_type s, buf* bufs,
+    size_t count, int flags, asio::error_code& ec);
+
+ASIO_DECL size_t sync_recv(socket_type s, state_type state, buf* bufs,
+    size_t count, int flags, bool all_empty, asio::error_code& ec);
+
+#if defined(ASIO_HAS_IOCP)
+
+ASIO_DECL void complete_iocp_recv(state_type state,
+    const weak_cancel_token_type& cancel_token, bool all_empty,
+    asio::error_code& ec, size_t bytes_transferred);
+
+#else // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL bool non_blocking_recv(socket_type s,
+    buf* bufs, size_t count, int flags, bool is_stream,
+    asio::error_code& ec, size_t& bytes_transferred);
+
+#endif // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL signed_size_type recvfrom(socket_type s, buf* bufs,
+    size_t count, int flags, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec);
+
+ASIO_DECL size_t sync_recvfrom(socket_type s, state_type state,
+    buf* bufs, size_t count, int flags, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec);
+
+#if defined(ASIO_HAS_IOCP)
+
+ASIO_DECL void complete_iocp_recvfrom(
+    const weak_cancel_token_type& cancel_token,
+    asio::error_code& ec);
+
+#else // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL bool non_blocking_recvfrom(socket_type s,
+    buf* bufs, size_t count, int flags,
+    socket_addr_type* addr, std::size_t* addrlen,
+    asio::error_code& ec, size_t& bytes_transferred);
+
+#endif // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL signed_size_type recvmsg(socket_type s, buf* bufs,
+    size_t count, int in_flags, int& out_flags,
+    asio::error_code& ec);
+
+ASIO_DECL size_t sync_recvmsg(socket_type s, state_type state,
+    buf* bufs, size_t count, int in_flags, int& out_flags,
+    asio::error_code& ec);
+
+#if defined(ASIO_HAS_IOCP)
+
+ASIO_DECL void complete_iocp_recvmsg(
+    const weak_cancel_token_type& cancel_token,
+    asio::error_code& ec);
+
+#else // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL bool non_blocking_recvmsg(socket_type s,
+    buf* bufs, size_t count, int in_flags, int& out_flags,
+    asio::error_code& ec, size_t& bytes_transferred);
+
+#endif // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL signed_size_type send(socket_type s, const buf* bufs,
+    size_t count, int flags, asio::error_code& ec);
+
+ASIO_DECL size_t sync_send(socket_type s, state_type state,
+    const buf* bufs, size_t count, int flags,
+    bool all_empty, asio::error_code& ec);
+
+#if defined(ASIO_HAS_IOCP)
+
+ASIO_DECL void complete_iocp_send(
+    const weak_cancel_token_type& cancel_token,
+    asio::error_code& ec);
+
+#else // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL bool non_blocking_send(socket_type s,
+    const buf* bufs, size_t count, int flags,
+    asio::error_code& ec, size_t& bytes_transferred);
+
+#endif // defined(ASIO_HAS_IOCP)
+
+ASIO_DECL signed_size_type sendto(socket_type s, const buf* bufs,
+    size_t count, int flags, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec);
+
+ASIO_DECL size_t sync_sendto(socket_type s, state_type state,
+    const buf* bufs, size_t count, int flags, const socket_addr_type* addr,
+    std::size_t addrlen, asio::error_code& ec);
+
+#if !defined(ASIO_HAS_IOCP)
+
+ASIO_DECL bool non_blocking_sendto(socket_type s,
+    const buf* bufs, size_t count, int flags,
+    const socket_addr_type* addr, std::size_t addrlen,
+    asio::error_code& ec, size_t& bytes_transferred);
+
+#endif // !defined(ASIO_HAS_IOCP)
+
+ASIO_DECL socket_type socket(int af, int type, int protocol,
+    asio::error_code& ec);
+
+ASIO_DECL int setsockopt(socket_type s, state_type& state,
+    int level, int optname, const void* optval,
+    std::size_t optlen, asio::error_code& ec);
+
+ASIO_DECL int getsockopt(socket_type s, state_type state,
+    int level, int optname, void* optval,
+    size_t* optlen, asio::error_code& ec);
+
+ASIO_DECL int getpeername(socket_type s, socket_addr_type* addr,
+    std::size_t* addrlen, bool cached, asio::error_code& ec);
+
+ASIO_DECL int getsockname(socket_type s, socket_addr_type* addr,
+    std::size_t* addrlen, asio::error_code& ec);
+
+ASIO_DECL int ioctl(socket_type s, state_type& state,
+    int cmd, ioctl_arg_type* arg, asio::error_code& ec);
+
+ASIO_DECL int select(int nfds, fd_set* readfds, fd_set* writefds,
+    fd_set* exceptfds, timeval* timeout, asio::error_code& ec);
+
+ASIO_DECL int poll_read(socket_type s,
+    state_type state, int msec, asio::error_code& ec);
+
+ASIO_DECL int poll_write(socket_type s,
+    state_type state, int msec, asio::error_code& ec);
+
+ASIO_DECL int poll_error(socket_type s,
+    state_type state, int msec, asio::error_code& ec);
+
+ASIO_DECL int poll_connect(socket_type s,
+    int msec, asio::error_code& ec);
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+ASIO_DECL const char* inet_ntop(int af, const void* src, char* dest,
+    size_t length, unsigned long scope_id, asio::error_code& ec);
+
+ASIO_DECL int inet_pton(int af, const char* src, void* dest,
+    unsigned long* scope_id, asio::error_code& ec);
+
+ASIO_DECL int gethostname(char* name,
+    int namelen, asio::error_code& ec);
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+ASIO_DECL asio::error_code getaddrinfo(const char* host,
+    const char* service, const addrinfo_type& hints,
+    addrinfo_type** result, asio::error_code& ec);
+
+ASIO_DECL asio::error_code background_getaddrinfo(
+    const weak_cancel_token_type& cancel_token, const char* host,
+    const char* service, const addrinfo_type& hints,
+    addrinfo_type** result, asio::error_code& ec);
+
+ASIO_DECL void freeaddrinfo(addrinfo_type* ai);
+
+ASIO_DECL asio::error_code getnameinfo(
+    const socket_addr_type* addr, std::size_t addrlen,
+    char* host, std::size_t hostlen, char* serv,
+    std::size_t servlen, int flags, asio::error_code& ec);
+
+ASIO_DECL asio::error_code sync_getnameinfo(
+    const socket_addr_type* addr, std::size_t addrlen,
+    char* host, std::size_t hostlen, char* serv,
+    std::size_t servlen, int sock_type, asio::error_code& ec);
+
+ASIO_DECL asio::error_code background_getnameinfo(
+    const weak_cancel_token_type& cancel_token,
+    const socket_addr_type* addr, std::size_t addrlen,
+    char* host, std::size_t hostlen, char* serv,
+    std::size_t servlen, int sock_type, asio::error_code& ec);
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+ASIO_DECL u_long_type network_to_host_long(u_long_type value);
+
+ASIO_DECL u_long_type host_to_network_long(u_long_type value);
+
+ASIO_DECL u_short_type network_to_host_short(u_short_type value);
+
+ASIO_DECL u_short_type host_to_network_short(u_short_type value);
+
+} // namespace socket_ops
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/socket_ops.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_SOCKET_OPS_HPP
diff --git a/subprojects/asio/include/asio/detail/socket_option.hpp b/subprojects/asio/include/asio/detail/socket_option.hpp
new file mode 100644
index 000000000..6852d5699
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/socket_option.hpp
@@ -0,0 +1,316 @@
+//
+// detail/socket_option.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SOCKET_OPTION_HPP
+#define ASIO_DETAIL_SOCKET_OPTION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <stdexcept>
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_exception.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace socket_option {
+
+// Helper template for implementing boolean-based options.
+template <int Level, int Name>
+class boolean
+{
+public:
+  // Default constructor.
+  boolean()
+    : value_(0)
+  {
+  }
+
+  // Construct with a specific option value.
+  explicit boolean(bool v)
+    : value_(v ? 1 : 0)
+  {
+  }
+
+  // Set the current value of the boolean.
+  boolean& operator=(bool v)
+  {
+    value_ = v ? 1 : 0;
+    return *this;
+  }
+
+  // Get the current value of the boolean.
+  bool value() const
+  {
+    return !!value_;
+  }
+
+  // Convert to bool.
+  operator bool() const
+  {
+    return !!value_;
+  }
+
+  // Test for false.
+  bool operator!() const
+  {
+    return !value_;
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol&) const
+  {
+    return Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol&) const
+  {
+    return Name;
+  }
+
+  // Get the address of the boolean data.
+  template <typename Protocol>
+  int* data(const Protocol&)
+  {
+    return &value_;
+  }
+
+  // Get the address of the boolean data.
+  template <typename Protocol>
+  const int* data(const Protocol&) const
+  {
+    return &value_;
+  }
+
+  // Get the size of the boolean data.
+  template <typename Protocol>
+  std::size_t size(const Protocol&) const
+  {
+    return sizeof(value_);
+  }
+
+  // Set the size of the boolean data.
+  template <typename Protocol>
+  void resize(const Protocol&, std::size_t s)
+  {
+    // On some platforms (e.g. Windows Vista), the getsockopt function will
+    // return the size of a boolean socket option as one byte, even though a
+    // four byte integer was passed in.
+    switch (s)
+    {
+    case sizeof(char):
+      value_ = *reinterpret_cast<char*>(&value_) ? 1 : 0;
+      break;
+    case sizeof(value_):
+      break;
+    default:
+      {
+        std::length_error ex("boolean socket option resize");
+        asio::detail::throw_exception(ex);
+      }
+    }
+  }
+
+private:
+  int value_;
+};
+
+// Helper template for implementing integer options.
+template <int Level, int Name>
+class integer
+{
+public:
+  // Default constructor.
+  integer()
+    : value_(0)
+  {
+  }
+
+  // Construct with a specific option value.
+  explicit integer(int v)
+    : value_(v)
+  {
+  }
+
+  // Set the value of the int option.
+  integer& operator=(int v)
+  {
+    value_ = v;
+    return *this;
+  }
+
+  // Get the current value of the int option.
+  int value() const
+  {
+    return value_;
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol&) const
+  {
+    return Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol&) const
+  {
+    return Name;
+  }
+
+  // Get the address of the int data.
+  template <typename Protocol>
+  int* data(const Protocol&)
+  {
+    return &value_;
+  }
+
+  // Get the address of the int data.
+  template <typename Protocol>
+  const int* data(const Protocol&) const
+  {
+    return &value_;
+  }
+
+  // Get the size of the int data.
+  template <typename Protocol>
+  std::size_t size(const Protocol&) const
+  {
+    return sizeof(value_);
+  }
+
+  // Set the size of the int data.
+  template <typename Protocol>
+  void resize(const Protocol&, std::size_t s)
+  {
+    if (s != sizeof(value_))
+    {
+      std::length_error ex("integer socket option resize");
+      asio::detail::throw_exception(ex);
+    }
+  }
+
+private:
+  int value_;
+};
+
+// Helper template for implementing linger options.
+template <int Level, int Name>
+class linger
+{
+public:
+  // Default constructor.
+  linger()
+  {
+    value_.l_onoff = 0;
+    value_.l_linger = 0;
+  }
+
+  // Construct with specific option values.
+  linger(bool e, int t)
+  {
+    enabled(e);
+    timeout ASIO_PREVENT_MACRO_SUBSTITUTION(t);
+  }
+
+  // Set the value for whether linger is enabled.
+  void enabled(bool value)
+  {
+    value_.l_onoff = value ? 1 : 0;
+  }
+
+  // Get the value for whether linger is enabled.
+  bool enabled() const
+  {
+    return value_.l_onoff != 0;
+  }
+
+  // Set the value for the linger timeout.
+  void timeout ASIO_PREVENT_MACRO_SUBSTITUTION(int value)
+  {
+#if defined(WIN32)
+    value_.l_linger = static_cast<u_short>(value);
+#else
+    value_.l_linger = value;
+#endif
+  }
+
+  // Get the value for the linger timeout.
+  int timeout ASIO_PREVENT_MACRO_SUBSTITUTION() const
+  {
+    return static_cast<int>(value_.l_linger);
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol&) const
+  {
+    return Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol&) const
+  {
+    return Name;
+  }
+
+  // Get the address of the linger data.
+  template <typename Protocol>
+  detail::linger_type* data(const Protocol&)
+  {
+    return &value_;
+  }
+
+  // Get the address of the linger data.
+  template <typename Protocol>
+  const detail::linger_type* data(const Protocol&) const
+  {
+    return &value_;
+  }
+
+  // Get the size of the linger data.
+  template <typename Protocol>
+  std::size_t size(const Protocol&) const
+  {
+    return sizeof(value_);
+  }
+
+  // Set the size of the int data.
+  template <typename Protocol>
+  void resize(const Protocol&, std::size_t s)
+  {
+    if (s != sizeof(value_))
+    {
+      std::length_error ex("linger socket option resize");
+      asio::detail::throw_exception(ex);
+    }
+  }
+
+private:
+  detail::linger_type value_;
+};
+
+} // namespace socket_option
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SOCKET_OPTION_HPP
diff --git a/subprojects/asio/include/asio/detail/socket_select_interrupter.hpp b/subprojects/asio/include/asio/detail/socket_select_interrupter.hpp
new file mode 100644
index 000000000..7351070ca
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/socket_select_interrupter.hpp
@@ -0,0 +1,91 @@
+//
+// detail/socket_select_interrupter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SOCKET_SELECT_INTERRUPTER_HPP
+#define ASIO_DETAIL_SOCKET_SELECT_INTERRUPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_WINDOWS_RUNTIME)
+
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(__SYMBIAN32__)
+
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class socket_select_interrupter
+{
+public:
+  // Constructor.
+  ASIO_DECL socket_select_interrupter();
+
+  // Destructor.
+  ASIO_DECL ~socket_select_interrupter();
+
+  // Recreate the interrupter's descriptors. Used after a fork.
+  ASIO_DECL void recreate();
+
+  // Interrupt the select call.
+  ASIO_DECL void interrupt();
+
+  // Reset the select interrupt. Returns true if the call was interrupted.
+  ASIO_DECL bool reset();
+
+  // Get the read descriptor to be passed to select.
+  socket_type read_descriptor() const
+  {
+    return read_descriptor_;
+  }
+
+private:
+  // Open the descriptors. Throws on error.
+  ASIO_DECL void open_descriptors();
+
+  // Close the descriptors.
+  ASIO_DECL void close_descriptors();
+
+  // The read end of a connection used to interrupt the select call. This file
+  // descriptor is passed to select such that when it is time to stop, a single
+  // byte will be written on the other end of the connection and this
+  // descriptor will become readable.
+  socket_type read_descriptor_;
+
+  // The write end of a connection used to interrupt the select call. A single
+  // byte may be written to this to wake up the select which is waiting for the
+  // other end to become readable.
+  socket_type write_descriptor_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/socket_select_interrupter.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS)
+       // || defined(__CYGWIN__)
+       // || defined(__SYMBIAN32__)
+
+#endif // !defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_SOCKET_SELECT_INTERRUPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/socket_types.hpp b/subprojects/asio/include/asio/detail/socket_types.hpp
new file mode 100644
index 000000000..d354343c0
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/socket_types.hpp
@@ -0,0 +1,416 @@
+//
+// detail/socket_types.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SOCKET_TYPES_HPP
+#define ASIO_DETAIL_SOCKET_TYPES_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+// Empty.
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# if defined(_WINSOCKAPI_) && !defined(_WINSOCK2API_)
+#  error WinSock.h has already been included
+# endif // defined(_WINSOCKAPI_) && !defined(_WINSOCK2API_)
+# if defined(__BORLANDC__)
+#  include <stdlib.h> // Needed for __errno
+#  if !defined(_WSPIAPI_H_)
+#   define _WSPIAPI_H_
+#   define ASIO_WSPIAPI_H_DEFINED
+#  endif // !defined(_WSPIAPI_H_)
+# endif // defined(__BORLANDC__)
+# include <winsock2.h>
+# include <ws2tcpip.h>
+# if defined(WINAPI_FAMILY)
+#  if ((WINAPI_FAMILY & WINAPI_PARTITION_DESKTOP) != 0)
+#   include <windows.h>
+#  endif // ((WINAPI_FAMILY & WINAPI_PARTITION_DESKTOP) != 0)
+# endif // defined(WINAPI_FAMILY)
+# if !defined(ASIO_WINDOWS_APP)
+#  include <mswsock.h>
+# endif // !defined(ASIO_WINDOWS_APP)
+# if defined(ASIO_WSPIAPI_H_DEFINED)
+#  undef _WSPIAPI_H_
+#  undef ASIO_WSPIAPI_H_DEFINED
+# endif // defined(ASIO_WSPIAPI_H_DEFINED)
+# if !defined(ASIO_NO_DEFAULT_LINKED_LIBS)
+#  if defined(UNDER_CE)
+#   pragma comment(lib, "ws2.lib")
+#  elif defined(_MSC_VER) || defined(__BORLANDC__)
+#   pragma comment(lib, "ws2_32.lib")
+#   if !defined(ASIO_WINDOWS_APP)
+#    pragma comment(lib, "mswsock.lib")
+#   endif // !defined(ASIO_WINDOWS_APP)
+#  endif // defined(_MSC_VER) || defined(__BORLANDC__)
+# endif // !defined(ASIO_NO_DEFAULT_LINKED_LIBS)
+# include "asio/detail/old_win_sdk_compat.hpp"
+#else
+# include <sys/ioctl.h>
+# if (defined(__MACH__) && defined(__APPLE__)) \
+   || defined(__FreeBSD__) || defined(__NetBSD__) \
+   || defined(__OpenBSD__) || defined(__linux__) \
+   || defined(__EMSCRIPTEN__)
+#  include <poll.h>
+# elif !defined(__SYMBIAN32__)
+#  include <sys/poll.h>
+# endif
+# include <sys/types.h>
+# include <sys/stat.h>
+# include <fcntl.h>
+# if defined(__hpux)
+#  include <sys/time.h>
+# endif
+# if !defined(__hpux) || defined(__SELECT)
+#  include <sys/select.h>
+# endif
+# include <sys/socket.h>
+# include <sys/uio.h>
+# include <sys/un.h>
+# include <netinet/in.h>
+# if !defined(__SYMBIAN32__)
+#  include <netinet/tcp.h>
+# endif
+# include <arpa/inet.h>
+# include <netdb.h>
+# include <net/if.h>
+# include <limits.h>
+# if defined(__sun)
+#  include <sys/filio.h>
+#  include <sys/sockio.h>
+# endif
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+const int max_addr_v4_str_len = 256;
+const int max_addr_v6_str_len = 256;
+typedef unsigned __int32 u_long_type;
+typedef unsigned __int16 u_short_type;
+struct in4_addr_type { u_long_type s_addr; };
+struct in4_mreq_type { in4_addr_type imr_multiaddr, imr_interface; };
+struct in6_addr_type { unsigned char s6_addr[16]; };
+struct in6_mreq_type { in6_addr_type ipv6mr_multiaddr;
+  unsigned long ipv6mr_interface; };
+struct socket_addr_type { int sa_family; };
+struct sockaddr_in4_type { int sin_family;
+  in4_addr_type sin_addr; u_short_type sin_port; };
+struct sockaddr_in6_type { int sin6_family;
+  in6_addr_type sin6_addr; u_short_type sin6_port;
+  u_long_type sin6_flowinfo; u_long_type sin6_scope_id; };
+struct sockaddr_storage_type { int ss_family;
+  unsigned char ss_bytes[128 - sizeof(int)]; };
+struct addrinfo_type { int ai_flags;
+  int ai_family, ai_socktype, ai_protocol;
+  int ai_addrlen; const void* ai_addr;
+  const char* ai_canonname; addrinfo_type* ai_next; };
+struct linger_type { u_short_type l_onoff, l_linger; };
+typedef u_long_type ioctl_arg_type;
+typedef int signed_size_type;
+# define ASIO_OS_DEF(c) ASIO_OS_DEF_##c
+# define ASIO_OS_DEF_AF_UNSPEC 0
+# define ASIO_OS_DEF_AF_INET 2
+# define ASIO_OS_DEF_AF_INET6 23
+# define ASIO_OS_DEF_SOCK_STREAM 1
+# define ASIO_OS_DEF_SOCK_DGRAM 2
+# define ASIO_OS_DEF_SOCK_RAW 3
+# define ASIO_OS_DEF_SOCK_SEQPACKET 5
+# define ASIO_OS_DEF_IPPROTO_IP 0
+# define ASIO_OS_DEF_IPPROTO_IPV6 41
+# define ASIO_OS_DEF_IPPROTO_TCP 6
+# define ASIO_OS_DEF_IPPROTO_UDP 17
+# define ASIO_OS_DEF_IPPROTO_ICMP 1
+# define ASIO_OS_DEF_IPPROTO_ICMPV6 58
+# define ASIO_OS_DEF_FIONBIO 1
+# define ASIO_OS_DEF_FIONREAD 2
+# define ASIO_OS_DEF_INADDR_ANY 0
+# define ASIO_OS_DEF_MSG_OOB 0x1
+# define ASIO_OS_DEF_MSG_PEEK 0x2
+# define ASIO_OS_DEF_MSG_DONTROUTE 0x4
+# define ASIO_OS_DEF_MSG_EOR 0 // Not supported.
+# define ASIO_OS_DEF_SHUT_RD 0x0
+# define ASIO_OS_DEF_SHUT_WR 0x1
+# define ASIO_OS_DEF_SHUT_RDWR 0x2
+# define ASIO_OS_DEF_SOMAXCONN 0x7fffffff
+# define ASIO_OS_DEF_SOL_SOCKET 0xffff
+# define ASIO_OS_DEF_SO_BROADCAST 0x20
+# define ASIO_OS_DEF_SO_DEBUG 0x1
+# define ASIO_OS_DEF_SO_DONTROUTE 0x10
+# define ASIO_OS_DEF_SO_KEEPALIVE 0x8
+# define ASIO_OS_DEF_SO_LINGER 0x80
+# define ASIO_OS_DEF_SO_OOBINLINE 0x100
+# define ASIO_OS_DEF_SO_SNDBUF 0x1001
+# define ASIO_OS_DEF_SO_RCVBUF 0x1002
+# define ASIO_OS_DEF_SO_SNDLOWAT 0x1003
+# define ASIO_OS_DEF_SO_RCVLOWAT 0x1004
+# define ASIO_OS_DEF_SO_REUSEADDR 0x4
+# define ASIO_OS_DEF_TCP_NODELAY 0x1
+# define ASIO_OS_DEF_IP_MULTICAST_IF 2
+# define ASIO_OS_DEF_IP_MULTICAST_TTL 3
+# define ASIO_OS_DEF_IP_MULTICAST_LOOP 4
+# define ASIO_OS_DEF_IP_ADD_MEMBERSHIP 5
+# define ASIO_OS_DEF_IP_DROP_MEMBERSHIP 6
+# define ASIO_OS_DEF_IP_TTL 7
+# define ASIO_OS_DEF_IPV6_UNICAST_HOPS 4
+# define ASIO_OS_DEF_IPV6_MULTICAST_IF 9
+# define ASIO_OS_DEF_IPV6_MULTICAST_HOPS 10
+# define ASIO_OS_DEF_IPV6_MULTICAST_LOOP 11
+# define ASIO_OS_DEF_IPV6_JOIN_GROUP 12
+# define ASIO_OS_DEF_IPV6_LEAVE_GROUP 13
+# define ASIO_OS_DEF_AI_CANONNAME 0x2
+# define ASIO_OS_DEF_AI_PASSIVE 0x1
+# define ASIO_OS_DEF_AI_NUMERICHOST 0x4
+# define ASIO_OS_DEF_AI_NUMERICSERV 0x8
+# define ASIO_OS_DEF_AI_V4MAPPED 0x800
+# define ASIO_OS_DEF_AI_ALL 0x100
+# define ASIO_OS_DEF_AI_ADDRCONFIG 0x400
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+typedef SOCKET socket_type;
+const SOCKET invalid_socket = INVALID_SOCKET;
+const int socket_error_retval = SOCKET_ERROR;
+const int max_addr_v4_str_len = 256;
+const int max_addr_v6_str_len = 256;
+typedef sockaddr socket_addr_type;
+typedef in_addr in4_addr_type;
+typedef ip_mreq in4_mreq_type;
+typedef sockaddr_in sockaddr_in4_type;
+# if defined(ASIO_HAS_OLD_WIN_SDK)
+typedef in6_addr_emulation in6_addr_type;
+typedef ipv6_mreq_emulation in6_mreq_type;
+typedef sockaddr_in6_emulation sockaddr_in6_type;
+typedef sockaddr_storage_emulation sockaddr_storage_type;
+typedef addrinfo_emulation addrinfo_type;
+# else
+typedef in6_addr in6_addr_type;
+typedef ipv6_mreq in6_mreq_type;
+typedef sockaddr_in6 sockaddr_in6_type;
+typedef sockaddr_storage sockaddr_storage_type;
+typedef addrinfo addrinfo_type;
+# endif
+typedef ::linger linger_type;
+typedef unsigned long ioctl_arg_type;
+typedef u_long u_long_type;
+typedef u_short u_short_type;
+typedef int signed_size_type;
+# define ASIO_OS_DEF(c) ASIO_OS_DEF_##c
+# define ASIO_OS_DEF_AF_UNSPEC AF_UNSPEC
+# define ASIO_OS_DEF_AF_INET AF_INET
+# define ASIO_OS_DEF_AF_INET6 AF_INET6
+# define ASIO_OS_DEF_SOCK_STREAM SOCK_STREAM
+# define ASIO_OS_DEF_SOCK_DGRAM SOCK_DGRAM
+# define ASIO_OS_DEF_SOCK_RAW SOCK_RAW
+# define ASIO_OS_DEF_SOCK_SEQPACKET SOCK_SEQPACKET
+# define ASIO_OS_DEF_IPPROTO_IP IPPROTO_IP
+# define ASIO_OS_DEF_IPPROTO_IPV6 IPPROTO_IPV6
+# define ASIO_OS_DEF_IPPROTO_TCP IPPROTO_TCP
+# define ASIO_OS_DEF_IPPROTO_UDP IPPROTO_UDP
+# define ASIO_OS_DEF_IPPROTO_ICMP IPPROTO_ICMP
+# define ASIO_OS_DEF_IPPROTO_ICMPV6 IPPROTO_ICMPV6
+# define ASIO_OS_DEF_FIONBIO FIONBIO
+# define ASIO_OS_DEF_FIONREAD FIONREAD
+# define ASIO_OS_DEF_INADDR_ANY INADDR_ANY
+# define ASIO_OS_DEF_MSG_OOB MSG_OOB
+# define ASIO_OS_DEF_MSG_PEEK MSG_PEEK
+# define ASIO_OS_DEF_MSG_DONTROUTE MSG_DONTROUTE
+# define ASIO_OS_DEF_MSG_EOR 0 // Not supported on Windows.
+# define ASIO_OS_DEF_SHUT_RD SD_RECEIVE
+# define ASIO_OS_DEF_SHUT_WR SD_SEND
+# define ASIO_OS_DEF_SHUT_RDWR SD_BOTH
+# define ASIO_OS_DEF_SOMAXCONN SOMAXCONN
+# define ASIO_OS_DEF_SOL_SOCKET SOL_SOCKET
+# define ASIO_OS_DEF_SO_BROADCAST SO_BROADCAST
+# define ASIO_OS_DEF_SO_DEBUG SO_DEBUG
+# define ASIO_OS_DEF_SO_DONTROUTE SO_DONTROUTE
+# define ASIO_OS_DEF_SO_KEEPALIVE SO_KEEPALIVE
+# define ASIO_OS_DEF_SO_LINGER SO_LINGER
+# define ASIO_OS_DEF_SO_OOBINLINE SO_OOBINLINE
+# define ASIO_OS_DEF_SO_SNDBUF SO_SNDBUF
+# define ASIO_OS_DEF_SO_RCVBUF SO_RCVBUF
+# define ASIO_OS_DEF_SO_SNDLOWAT SO_SNDLOWAT
+# define ASIO_OS_DEF_SO_RCVLOWAT SO_RCVLOWAT
+# define ASIO_OS_DEF_SO_REUSEADDR SO_REUSEADDR
+# define ASIO_OS_DEF_TCP_NODELAY TCP_NODELAY
+# define ASIO_OS_DEF_IP_MULTICAST_IF IP_MULTICAST_IF
+# define ASIO_OS_DEF_IP_MULTICAST_TTL IP_MULTICAST_TTL
+# define ASIO_OS_DEF_IP_MULTICAST_LOOP IP_MULTICAST_LOOP
+# define ASIO_OS_DEF_IP_ADD_MEMBERSHIP IP_ADD_MEMBERSHIP
+# define ASIO_OS_DEF_IP_DROP_MEMBERSHIP IP_DROP_MEMBERSHIP
+# define ASIO_OS_DEF_IP_TTL IP_TTL
+# define ASIO_OS_DEF_IPV6_UNICAST_HOPS IPV6_UNICAST_HOPS
+# define ASIO_OS_DEF_IPV6_MULTICAST_IF IPV6_MULTICAST_IF
+# define ASIO_OS_DEF_IPV6_MULTICAST_HOPS IPV6_MULTICAST_HOPS
+# define ASIO_OS_DEF_IPV6_MULTICAST_LOOP IPV6_MULTICAST_LOOP
+# define ASIO_OS_DEF_IPV6_JOIN_GROUP IPV6_JOIN_GROUP
+# define ASIO_OS_DEF_IPV6_LEAVE_GROUP IPV6_LEAVE_GROUP
+# define ASIO_OS_DEF_AI_CANONNAME AI_CANONNAME
+# define ASIO_OS_DEF_AI_PASSIVE AI_PASSIVE
+# define ASIO_OS_DEF_AI_NUMERICHOST AI_NUMERICHOST
+# if defined(AI_NUMERICSERV)
+#  define ASIO_OS_DEF_AI_NUMERICSERV AI_NUMERICSERV
+# else
+#  define ASIO_OS_DEF_AI_NUMERICSERV 0
+# endif
+# if defined(AI_V4MAPPED)
+#  define ASIO_OS_DEF_AI_V4MAPPED AI_V4MAPPED
+# else
+#  define ASIO_OS_DEF_AI_V4MAPPED 0
+# endif
+# if defined(AI_ALL)
+#  define ASIO_OS_DEF_AI_ALL AI_ALL
+# else
+#  define ASIO_OS_DEF_AI_ALL 0
+# endif
+# if defined(AI_ADDRCONFIG)
+#  define ASIO_OS_DEF_AI_ADDRCONFIG AI_ADDRCONFIG
+# else
+#  define ASIO_OS_DEF_AI_ADDRCONFIG 0
+# endif
+# if defined (_WIN32_WINNT)
+const int max_iov_len = 64;
+# else
+const int max_iov_len = 16;
+# endif
+#else
+typedef int socket_type;
+const int invalid_socket = -1;
+const int socket_error_retval = -1;
+const int max_addr_v4_str_len = INET_ADDRSTRLEN;
+#if defined(INET6_ADDRSTRLEN)
+const int max_addr_v6_str_len = INET6_ADDRSTRLEN + 1 + IF_NAMESIZE;
+#else // defined(INET6_ADDRSTRLEN)
+const int max_addr_v6_str_len = 256;
+#endif // defined(INET6_ADDRSTRLEN)
+typedef sockaddr socket_addr_type;
+typedef in_addr in4_addr_type;
+# if defined(__hpux)
+// HP-UX doesn't provide ip_mreq when _XOPEN_SOURCE_EXTENDED is defined.
+struct in4_mreq_type
+{
+  struct in_addr imr_multiaddr;
+  struct in_addr imr_interface;
+};
+# else
+typedef ip_mreq in4_mreq_type;
+# endif
+typedef sockaddr_in sockaddr_in4_type;
+typedef in6_addr in6_addr_type;
+typedef ipv6_mreq in6_mreq_type;
+typedef sockaddr_in6 sockaddr_in6_type;
+typedef sockaddr_storage sockaddr_storage_type;
+typedef sockaddr_un sockaddr_un_type;
+typedef addrinfo addrinfo_type;
+typedef ::linger linger_type;
+typedef int ioctl_arg_type;
+typedef uint32_t u_long_type;
+typedef uint16_t u_short_type;
+#if defined(ASIO_HAS_SSIZE_T)
+typedef ssize_t signed_size_type;
+#else // defined(ASIO_HAS_SSIZE_T)
+typedef int signed_size_type;
+#endif // defined(ASIO_HAS_SSIZE_T)
+# define ASIO_OS_DEF(c) ASIO_OS_DEF_##c
+# define ASIO_OS_DEF_AF_UNSPEC AF_UNSPEC
+# define ASIO_OS_DEF_AF_INET AF_INET
+# define ASIO_OS_DEF_AF_INET6 AF_INET6
+# define ASIO_OS_DEF_SOCK_STREAM SOCK_STREAM
+# define ASIO_OS_DEF_SOCK_DGRAM SOCK_DGRAM
+# define ASIO_OS_DEF_SOCK_RAW SOCK_RAW
+# define ASIO_OS_DEF_SOCK_SEQPACKET SOCK_SEQPACKET
+# define ASIO_OS_DEF_IPPROTO_IP IPPROTO_IP
+# define ASIO_OS_DEF_IPPROTO_IPV6 IPPROTO_IPV6
+# define ASIO_OS_DEF_IPPROTO_TCP IPPROTO_TCP
+# define ASIO_OS_DEF_IPPROTO_UDP IPPROTO_UDP
+# define ASIO_OS_DEF_IPPROTO_ICMP IPPROTO_ICMP
+# define ASIO_OS_DEF_IPPROTO_ICMPV6 IPPROTO_ICMPV6
+# define ASIO_OS_DEF_FIONBIO FIONBIO
+# define ASIO_OS_DEF_FIONREAD FIONREAD
+# define ASIO_OS_DEF_INADDR_ANY INADDR_ANY
+# define ASIO_OS_DEF_MSG_OOB MSG_OOB
+# define ASIO_OS_DEF_MSG_PEEK MSG_PEEK
+# define ASIO_OS_DEF_MSG_DONTROUTE MSG_DONTROUTE
+# define ASIO_OS_DEF_MSG_EOR MSG_EOR
+# define ASIO_OS_DEF_SHUT_RD SHUT_RD
+# define ASIO_OS_DEF_SHUT_WR SHUT_WR
+# define ASIO_OS_DEF_SHUT_RDWR SHUT_RDWR
+# define ASIO_OS_DEF_SOMAXCONN SOMAXCONN
+# define ASIO_OS_DEF_SOL_SOCKET SOL_SOCKET
+# define ASIO_OS_DEF_SO_BROADCAST SO_BROADCAST
+# define ASIO_OS_DEF_SO_DEBUG SO_DEBUG
+# define ASIO_OS_DEF_SO_DONTROUTE SO_DONTROUTE
+# define ASIO_OS_DEF_SO_KEEPALIVE SO_KEEPALIVE
+# define ASIO_OS_DEF_SO_LINGER SO_LINGER
+# define ASIO_OS_DEF_SO_OOBINLINE SO_OOBINLINE
+# define ASIO_OS_DEF_SO_SNDBUF SO_SNDBUF
+# define ASIO_OS_DEF_SO_RCVBUF SO_RCVBUF
+# define ASIO_OS_DEF_SO_SNDLOWAT SO_SNDLOWAT
+# define ASIO_OS_DEF_SO_RCVLOWAT SO_RCVLOWAT
+# define ASIO_OS_DEF_SO_REUSEADDR SO_REUSEADDR
+# define ASIO_OS_DEF_TCP_NODELAY TCP_NODELAY
+# define ASIO_OS_DEF_IP_MULTICAST_IF IP_MULTICAST_IF
+# define ASIO_OS_DEF_IP_MULTICAST_TTL IP_MULTICAST_TTL
+# define ASIO_OS_DEF_IP_MULTICAST_LOOP IP_MULTICAST_LOOP
+# define ASIO_OS_DEF_IP_ADD_MEMBERSHIP IP_ADD_MEMBERSHIP
+# define ASIO_OS_DEF_IP_DROP_MEMBERSHIP IP_DROP_MEMBERSHIP
+# define ASIO_OS_DEF_IP_TTL IP_TTL
+# define ASIO_OS_DEF_IPV6_UNICAST_HOPS IPV6_UNICAST_HOPS
+# define ASIO_OS_DEF_IPV6_MULTICAST_IF IPV6_MULTICAST_IF
+# define ASIO_OS_DEF_IPV6_MULTICAST_HOPS IPV6_MULTICAST_HOPS
+# define ASIO_OS_DEF_IPV6_MULTICAST_LOOP IPV6_MULTICAST_LOOP
+# define ASIO_OS_DEF_IPV6_JOIN_GROUP IPV6_JOIN_GROUP
+# define ASIO_OS_DEF_IPV6_LEAVE_GROUP IPV6_LEAVE_GROUP
+# define ASIO_OS_DEF_AI_CANONNAME AI_CANONNAME
+# define ASIO_OS_DEF_AI_PASSIVE AI_PASSIVE
+# define ASIO_OS_DEF_AI_NUMERICHOST AI_NUMERICHOST
+# if defined(AI_NUMERICSERV)
+#  define ASIO_OS_DEF_AI_NUMERICSERV AI_NUMERICSERV
+# else
+#  define ASIO_OS_DEF_AI_NUMERICSERV 0
+# endif
+// Note: QNX Neutrino 6.3 defines AI_V4MAPPED, AI_ALL and AI_ADDRCONFIG but
+// does not implement them. Therefore they are specifically excluded here.
+# if defined(AI_V4MAPPED) && !defined(__QNXNTO__)
+#  define ASIO_OS_DEF_AI_V4MAPPED AI_V4MAPPED
+# else
+#  define ASIO_OS_DEF_AI_V4MAPPED 0
+# endif
+# if defined(AI_ALL) && !defined(__QNXNTO__)
+#  define ASIO_OS_DEF_AI_ALL AI_ALL
+# else
+#  define ASIO_OS_DEF_AI_ALL 0
+# endif
+# if defined(AI_ADDRCONFIG) && !defined(__QNXNTO__)
+#  define ASIO_OS_DEF_AI_ADDRCONFIG AI_ADDRCONFIG
+# else
+#  define ASIO_OS_DEF_AI_ADDRCONFIG 0
+# endif
+# if defined(IOV_MAX)
+const int max_iov_len = IOV_MAX;
+# else
+// POSIX platforms are not required to define IOV_MAX.
+const int max_iov_len = 16;
+# endif
+#endif
+const int custom_socket_option_level = 0xA5100000;
+const int enable_connection_aborted_option = 1;
+const int always_fail_option = 2;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_SOCKET_TYPES_HPP
diff --git a/subprojects/asio/include/asio/detail/solaris_fenced_block.hpp b/subprojects/asio/include/asio/detail/solaris_fenced_block.hpp
new file mode 100644
index 000000000..d48f6a374
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/solaris_fenced_block.hpp
@@ -0,0 +1,62 @@
+//
+// detail/solaris_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_SOLARIS_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_SOLARIS_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(__sun)
+
+#include <atomic.h>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class solaris_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_t { half };
+  enum full_t { full };
+
+  // Constructor for a half fenced block.
+  explicit solaris_fenced_block(half_t)
+  {
+  }
+
+  // Constructor for a full fenced block.
+  explicit solaris_fenced_block(full_t)
+  {
+    membar_consumer();
+  }
+
+  // Destructor.
+  ~solaris_fenced_block()
+  {
+    membar_producer();
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(__sun)
+
+#endif // ASIO_DETAIL_SOLARIS_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/static_mutex.hpp b/subprojects/asio/include/asio/detail/static_mutex.hpp
new file mode 100644
index 000000000..8f2bc02a0
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/static_mutex.hpp
@@ -0,0 +1,52 @@
+//
+// detail/static_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STATIC_MUTEX_HPP
+#define ASIO_DETAIL_STATIC_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+# include "asio/detail/null_static_mutex.hpp"
+#elif defined(ASIO_WINDOWS)
+# include "asio/detail/win_static_mutex.hpp"
+#elif defined(ASIO_HAS_PTHREADS)
+# include "asio/detail/posix_static_mutex.hpp"
+#elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+# include "asio/detail/std_static_mutex.hpp"
+#else
+# error Only Windows and POSIX are supported!
+#endif
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS)
+typedef null_static_mutex static_mutex;
+# define ASIO_STATIC_MUTEX_INIT ASIO_NULL_STATIC_MUTEX_INIT
+#elif defined(ASIO_WINDOWS)
+typedef win_static_mutex static_mutex;
+# define ASIO_STATIC_MUTEX_INIT ASIO_WIN_STATIC_MUTEX_INIT
+#elif defined(ASIO_HAS_PTHREADS)
+typedef posix_static_mutex static_mutex;
+# define ASIO_STATIC_MUTEX_INIT ASIO_POSIX_STATIC_MUTEX_INIT
+#elif defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+typedef std_static_mutex static_mutex;
+# define ASIO_STATIC_MUTEX_INIT ASIO_STD_STATIC_MUTEX_INIT
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_STATIC_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/std_event.hpp b/subprojects/asio/include/asio/detail/std_event.hpp
new file mode 100644
index 000000000..5639ecdd4
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/std_event.hpp
@@ -0,0 +1,176 @@
+//
+// detail/std_event.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STD_EVENT_HPP
+#define ASIO_DETAIL_STD_EVENT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+
+#include <chrono>
+#include <condition_variable>
+#include "asio/detail/assert.hpp"
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class std_event
+  : private noncopyable
+{
+public:
+  // Constructor.
+  std_event()
+    : state_(0)
+  {
+  }
+
+  // Destructor.
+  ~std_event()
+  {
+  }
+
+  // Signal the event. (Retained for backward compatibility.)
+  template <typename Lock>
+  void signal(Lock& lock)
+  {
+    this->signal_all(lock);
+  }
+
+  // Signal all waiters.
+  template <typename Lock>
+  void signal_all(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    (void)lock;
+    state_ |= 1;
+    cond_.notify_all();
+  }
+
+  // Unlock the mutex and signal one waiter.
+  template <typename Lock>
+  void unlock_and_signal_one(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    state_ |= 1;
+    bool have_waiters = (state_ > 1);
+    lock.unlock();
+    if (have_waiters)
+      cond_.notify_one();
+  }
+
+  // If there's a waiter, unlock the mutex and signal it.
+  template <typename Lock>
+  bool maybe_unlock_and_signal_one(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    state_ |= 1;
+    if (state_ > 1)
+    {
+      lock.unlock();
+      cond_.notify_one();
+      return true;
+    }
+    return false;
+  }
+
+  // Reset the event.
+  template <typename Lock>
+  void clear(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    (void)lock;
+    state_ &= ~std::size_t(1);
+  }
+
+  // Wait for the event to become signalled.
+  template <typename Lock>
+  void wait(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    unique_lock_adapter u_lock(lock);
+    while ((state_ & 1) == 0)
+    {
+      waiter w(state_);
+      cond_.wait(u_lock.unique_lock_);
+    }
+  }
+
+  // Timed wait for the event to become signalled.
+  template <typename Lock>
+  bool wait_for_usec(Lock& lock, long usec)
+  {
+    ASIO_ASSERT(lock.locked());
+    unique_lock_adapter u_lock(lock);
+    if ((state_ & 1) == 0)
+    {
+      waiter w(state_);
+      cond_.wait_for(u_lock.unique_lock_, std::chrono::microseconds(usec));
+    }
+    return (state_ & 1) != 0;
+  }
+
+private:
+  // Helper class to temporarily adapt a scoped_lock into a unique_lock so that
+  // it can be passed to std::condition_variable::wait().
+  struct unique_lock_adapter
+  {
+    template <typename Lock>
+    explicit unique_lock_adapter(Lock& lock)
+      : unique_lock_(lock.mutex().mutex_, std::adopt_lock)
+    {
+    }
+
+    ~unique_lock_adapter()
+    {
+      unique_lock_.release();
+    }
+
+    std::unique_lock<std::mutex> unique_lock_;
+  };
+
+  // Helper to increment and decrement the state to track outstanding waiters.
+  class waiter
+  {
+  public:
+    explicit waiter(std::size_t& state)
+      : state_(state)
+    {
+      state_ += 2;
+    }
+
+    ~waiter()
+    {
+      state_ -= 2;
+    }
+
+  private:
+    std::size_t& state_;
+  };
+
+  std::condition_variable cond_;
+  std::size_t state_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+
+#endif // ASIO_DETAIL_STD_EVENT_HPP
diff --git a/subprojects/asio/include/asio/detail/std_fenced_block.hpp b/subprojects/asio/include/asio/detail/std_fenced_block.hpp
new file mode 100644
index 000000000..0d8ade028
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/std_fenced_block.hpp
@@ -0,0 +1,62 @@
+//
+// detail/std_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STD_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_STD_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_ATOMIC)
+
+#include <atomic>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class std_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_t { half };
+  enum full_t { full };
+
+  // Constructor for a half fenced block.
+  explicit std_fenced_block(half_t)
+  {
+  }
+
+  // Constructor for a full fenced block.
+  explicit std_fenced_block(full_t)
+  {
+    std::atomic_thread_fence(std::memory_order_acquire);
+  }
+
+  // Destructor.
+  ~std_fenced_block()
+  {
+    std::atomic_thread_fence(std::memory_order_release);
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_STD_ATOMIC)
+
+#endif // ASIO_DETAIL_STD_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/std_global.hpp b/subprojects/asio/include/asio/detail/std_global.hpp
new file mode 100644
index 000000000..0c5173e6b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/std_global.hpp
@@ -0,0 +1,70 @@
+//
+// detail/std_global.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STD_GLOBAL_HPP
+#define ASIO_DETAIL_STD_GLOBAL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_CALL_ONCE)
+
+#include <exception>
+#include <mutex>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+struct std_global_impl
+{
+  // Helper function to perform initialisation.
+  static void do_init()
+  {
+    instance_.ptr_ = new T;
+  }
+
+  // Destructor automatically cleans up the global.
+  ~std_global_impl()
+  {
+    delete ptr_;
+  }
+
+  static std::once_flag init_once_;
+  static std_global_impl instance_;
+  T* ptr_;
+};
+
+template <typename T>
+std::once_flag std_global_impl<T>::init_once_;
+
+template <typename T>
+std_global_impl<T> std_global_impl<T>::instance_;
+
+template <typename T>
+T& std_global()
+{
+  std::call_once(std_global_impl<T>::init_once_, &std_global_impl<T>::do_init);
+  return *std_global_impl<T>::instance_.ptr_;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_STD_CALL_ONCE)
+
+#endif // ASIO_DETAIL_STD_GLOBAL_HPP
diff --git a/subprojects/asio/include/asio/detail/std_mutex.hpp b/subprojects/asio/include/asio/detail/std_mutex.hpp
new file mode 100644
index 000000000..159049e8c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/std_mutex.hpp
@@ -0,0 +1,73 @@
+//
+// detail/std_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STD_MUTEX_HPP
+#define ASIO_DETAIL_STD_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+
+#include <mutex>
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class std_event;
+
+class std_mutex
+  : private noncopyable
+{
+public:
+  typedef asio::detail::scoped_lock<std_mutex> scoped_lock;
+
+  // Constructor.
+  std_mutex()
+  {
+  }
+
+  // Destructor.
+  ~std_mutex()
+  {
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+    mutex_.lock();
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+    mutex_.unlock();
+  }
+
+private:
+  friend class std_event;
+  std::mutex mutex_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+
+#endif // ASIO_DETAIL_STD_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/std_static_mutex.hpp b/subprojects/asio/include/asio/detail/std_static_mutex.hpp
new file mode 100644
index 000000000..e9c9dc5ee
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/std_static_mutex.hpp
@@ -0,0 +1,81 @@
+//
+// detail/std_static_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STD_STATIC_MUTEX_HPP
+#define ASIO_DETAIL_STD_STATIC_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+
+#include <mutex>
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class std_event;
+
+class std_static_mutex
+  : private noncopyable
+{
+public:
+  typedef asio::detail::scoped_lock<std_static_mutex> scoped_lock;
+
+  // Constructor.
+  std_static_mutex(int)
+  {
+  }
+
+  // Destructor.
+  ~std_static_mutex()
+  {
+  }
+
+  // Initialise the mutex.
+  void init()
+  {
+    // Nothing to do.
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+    mutex_.lock();
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+    mutex_.unlock();
+  }
+
+private:
+  friend class std_event;
+  std::mutex mutex_;
+};
+
+#define ASIO_STD_STATIC_MUTEX_INIT 0
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_STD_MUTEX_AND_CONDVAR)
+
+#endif // ASIO_DETAIL_STD_STATIC_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/std_thread.hpp b/subprojects/asio/include/asio/detail/std_thread.hpp
new file mode 100644
index 000000000..a240308d8
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/std_thread.hpp
@@ -0,0 +1,71 @@
+//
+// detail/std_thread.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STD_THREAD_HPP
+#define ASIO_DETAIL_STD_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_THREAD)
+
+#include <thread>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class std_thread
+  : private noncopyable
+{
+public:
+  // Constructor.
+  template <typename Function>
+  std_thread(Function f, unsigned int = 0)
+    : thread_(f)
+  {
+  }
+
+  // Destructor.
+  ~std_thread()
+  {
+    join();
+  }
+
+  // Wait for the thread to exit.
+  void join()
+  {
+    if (thread_.joinable())
+      thread_.join();
+  }
+
+  // Get number of CPUs.
+  static std::size_t hardware_concurrency()
+  {
+    return std::thread::hardware_concurrency();
+  }
+
+private:
+  std::thread thread_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_STD_THREAD)
+
+#endif // ASIO_DETAIL_STD_THREAD_HPP
diff --git a/subprojects/asio/include/asio/detail/strand_executor_service.hpp b/subprojects/asio/include/asio/detail/strand_executor_service.hpp
new file mode 100644
index 000000000..67e84274b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/strand_executor_service.hpp
@@ -0,0 +1,142 @@
+//
+// detail/strand_executor_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STRAND_EXECUTOR_SERVICE_HPP
+#define ASIO_DETAIL_STRAND_EXECUTOR_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/atomic_count.hpp"
+#include "asio/detail/executor_op.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/scheduler_operation.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Default service implementation for a strand.
+class strand_executor_service
+  : public execution_context_service_base<strand_executor_service>
+{
+public:
+  // The underlying implementation of a strand.
+  class strand_impl
+  {
+  public:
+    ASIO_DECL ~strand_impl();
+
+  private:
+    friend class strand_executor_service;
+
+    // Mutex to protect access to internal data.
+    mutex* mutex_;
+
+    // Indicates whether the strand is currently "locked" by a handler. This
+    // means that there is a handler upcall in progress, or that the strand
+    // itself has been scheduled in order to invoke some pending handlers.
+    bool locked_;
+
+    // Indicates that the strand has been shut down and will accept no further
+    // handlers.
+    bool shutdown_;
+
+    // The handlers that are waiting on the strand but should not be run until
+    // after the next time the strand is scheduled. This queue must only be
+    // modified while the mutex is locked.
+    op_queue<scheduler_operation> waiting_queue_;
+
+    // The handlers that are ready to be run. Logically speaking, these are the
+    // handlers that hold the strand's lock. The ready queue is only modified
+    // from within the strand and so may be accessed without locking the mutex.
+    op_queue<scheduler_operation> ready_queue_;
+
+    // Pointers to adjacent handle implementations in linked list.
+    strand_impl* next_;
+    strand_impl* prev_;
+
+    // The strand service in where the implementation is held.
+    strand_executor_service* service_;
+  };
+
+  typedef shared_ptr<strand_impl> implementation_type;
+
+  // Construct a new strand service for the specified context.
+  ASIO_DECL explicit strand_executor_service(execution_context& context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Create a new strand_executor implementation.
+  ASIO_DECL implementation_type create_implementation();
+
+  // Request invocation of the given function.
+  template <typename Executor, typename Function, typename Allocator>
+  static void dispatch(const implementation_type& impl, Executor& ex,
+      ASIO_MOVE_ARG(Function) function, const Allocator& a);
+
+  // Request invocation of the given function and return immediately.
+  template <typename Executor, typename Function, typename Allocator>
+  static void post(const implementation_type& impl, Executor& ex,
+      ASIO_MOVE_ARG(Function) function, const Allocator& a);
+
+  // Request invocation of the given function and return immediately.
+  template <typename Executor, typename Function, typename Allocator>
+  static void defer(const implementation_type& impl, Executor& ex,
+      ASIO_MOVE_ARG(Function) function, const Allocator& a);
+
+  // Determine whether the strand is running in the current thread.
+  ASIO_DECL static bool running_in_this_thread(
+      const implementation_type& impl);
+
+private:
+  friend class strand_impl;
+  template <typename Executor> class invoker;
+
+  // Adds a function to the strand. Returns true if it acquires the lock.
+  ASIO_DECL static bool enqueue(const implementation_type& impl,
+      scheduler_operation* op);
+
+  // Mutex to protect access to the service-wide state.
+  mutex mutex_;
+
+  // Number of mutexes shared between all strand objects.
+  enum { num_mutexes = 193 };
+
+  // Pool of mutexes.
+  scoped_ptr<mutex> mutexes_[num_mutexes];
+
+  // Extra value used when hashing to prevent recycled memory locations from
+  // getting the same mutex.
+  std::size_t salt_;
+
+  // The head of a linked list of all implementations.
+  strand_impl* impl_list_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/strand_executor_service.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/strand_executor_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_STRAND_EXECUTOR_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/strand_service.hpp b/subprojects/asio/include/asio/detail/strand_service.hpp
new file mode 100644
index 000000000..edc14a0f7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/strand_service.hpp
@@ -0,0 +1,142 @@
+//
+// detail/strand_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STRAND_SERVICE_HPP
+#define ASIO_DETAIL_STRAND_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Default service implementation for a strand.
+class strand_service
+  : public asio::detail::service_base<strand_service>
+{
+private:
+  // Helper class to re-post the strand on exit.
+  struct on_do_complete_exit;
+
+  // Helper class to re-post the strand on exit.
+  struct on_dispatch_exit;
+
+public:
+
+  // The underlying implementation of a strand.
+  class strand_impl
+    : public operation
+  {
+  public:
+    strand_impl();
+
+  private:
+    // Only this service will have access to the internal values.
+    friend class strand_service;
+    friend struct on_do_complete_exit;
+    friend struct on_dispatch_exit;
+
+    // Mutex to protect access to internal data.
+    asio::detail::mutex mutex_;
+
+    // Indicates whether the strand is currently "locked" by a handler. This
+    // means that there is a handler upcall in progress, or that the strand
+    // itself has been scheduled in order to invoke some pending handlers.
+    bool locked_;
+
+    // The handlers that are waiting on the strand but should not be run until
+    // after the next time the strand is scheduled. This queue must only be
+    // modified while the mutex is locked.
+    op_queue<operation> waiting_queue_;
+
+    // The handlers that are ready to be run. Logically speaking, these are the
+    // handlers that hold the strand's lock. The ready queue is only modified
+    // from within the strand and so may be accessed without locking the mutex.
+    op_queue<operation> ready_queue_;
+  };
+
+  typedef strand_impl* implementation_type;
+
+  // Construct a new strand service for the specified io_context.
+  ASIO_DECL explicit strand_service(asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Construct a new strand implementation.
+  ASIO_DECL void construct(implementation_type& impl);
+
+  // Request the io_context to invoke the given handler.
+  template <typename Handler>
+  void dispatch(implementation_type& impl, Handler& handler);
+
+  // Request the io_context to invoke the given handler and return immediately.
+  template <typename Handler>
+  void post(implementation_type& impl, Handler& handler);
+
+  // Determine whether the strand is running in the current thread.
+  ASIO_DECL bool running_in_this_thread(
+      const implementation_type& impl) const;
+
+private:
+  // Helper function to dispatch a handler. Returns true if the handler should
+  // be dispatched immediately.
+  ASIO_DECL bool do_dispatch(implementation_type& impl, operation* op);
+
+  // Helper fiunction to post a handler.
+  ASIO_DECL void do_post(implementation_type& impl,
+      operation* op, bool is_continuation);
+
+  ASIO_DECL static void do_complete(void* owner,
+      operation* base, const asio::error_code& ec,
+      std::size_t bytes_transferred);
+
+  // The io_context implementation used to post completions.
+  io_context_impl& io_context_;
+
+  // Mutex to protect access to the array of implementations.
+  asio::detail::mutex mutex_;
+
+  // Number of implementations shared between all strand objects.
+#if defined(ASIO_STRAND_IMPLEMENTATIONS)
+  enum { num_implementations = ASIO_STRAND_IMPLEMENTATIONS };
+#else // defined(ASIO_STRAND_IMPLEMENTATIONS)
+  enum { num_implementations = 193 };
+#endif // defined(ASIO_STRAND_IMPLEMENTATIONS)
+
+  // Pool of implementations.
+  scoped_ptr<strand_impl> implementations_[num_implementations];
+
+  // Extra value used when hashing to prevent recycled memory locations from
+  // getting the same strand implementation.
+  std::size_t salt_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/strand_service.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/strand_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_STRAND_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/string_view.hpp b/subprojects/asio/include/asio/detail/string_view.hpp
new file mode 100644
index 000000000..f09cebc2b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/string_view.hpp
@@ -0,0 +1,47 @@
+//
+// detail/string_view.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_STRING_VIEW_HPP
+#define ASIO_DETAIL_STRING_VIEW_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STRING_VIEW)
+
+#if defined(ASIO_HAS_STD_STRING_VIEW)
+# include <string_view>
+#elif defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+# include <experimental/string_view>
+#else // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+# error ASIO_HAS_STRING_VIEW is set but no string_view is available
+#endif // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+
+namespace asio {
+
+#if defined(ASIO_HAS_STD_STRING_VIEW)
+using std::basic_string_view;
+using std::string_view;
+#elif defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+using std::experimental::basic_string_view;
+using std::experimental::string_view;
+#endif // defined(ASIO_HAS_STD_EXPERIMENTAL_STRING_VIEW)
+
+} // namespace asio
+
+# define ASIO_STRING_VIEW_PARAM asio::string_view
+#else // defined(ASIO_HAS_STRING_VIEW)
+# define ASIO_STRING_VIEW_PARAM const std::string&
+#endif // defined(ASIO_HAS_STRING_VIEW)
+
+#endif // ASIO_DETAIL_STRING_VIEW_HPP
diff --git a/subprojects/asio/include/asio/detail/thread.hpp b/subprojects/asio/include/asio/detail/thread.hpp
new file mode 100644
index 000000000..ea556dba6
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/thread.hpp
@@ -0,0 +1,60 @@
+//
+// detail/thread.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_THREAD_HPP
+#define ASIO_DETAIL_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+# include "asio/detail/null_thread.hpp"
+#elif defined(ASIO_WINDOWS)
+# if defined(UNDER_CE)
+#  include "asio/detail/wince_thread.hpp"
+# elif defined(ASIO_WINDOWS_APP)
+#  include "asio/detail/winapp_thread.hpp"
+# else
+#  include "asio/detail/win_thread.hpp"
+# endif
+#elif defined(ASIO_HAS_PTHREADS)
+# include "asio/detail/posix_thread.hpp"
+#elif defined(ASIO_HAS_STD_THREAD)
+# include "asio/detail/std_thread.hpp"
+#else
+# error Only Windows, POSIX and std::thread are supported!
+#endif
+
+namespace asio {
+namespace detail {
+
+#if !defined(ASIO_HAS_THREADS)
+typedef null_thread thread;
+#elif defined(ASIO_WINDOWS)
+# if defined(UNDER_CE)
+typedef wince_thread thread;
+# elif defined(ASIO_WINDOWS_APP)
+typedef winapp_thread thread;
+# else
+typedef win_thread thread;
+# endif
+#elif defined(ASIO_HAS_PTHREADS)
+typedef posix_thread thread;
+#elif defined(ASIO_HAS_STD_THREAD)
+typedef std_thread thread;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_THREAD_HPP
diff --git a/subprojects/asio/include/asio/detail/thread_context.hpp b/subprojects/asio/include/asio/detail/thread_context.hpp
new file mode 100644
index 000000000..88b4f3115
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/thread_context.hpp
@@ -0,0 +1,42 @@
+//
+// detail/thread_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_THREAD_CONTEXT_HPP
+#define ASIO_DETAIL_THREAD_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <climits>
+#include <cstddef>
+#include "asio/detail/call_stack.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class thread_info_base;
+
+// Base class for things that manage threads (scheduler, win_iocp_io_context).
+class thread_context
+{
+public:
+  // Per-thread call stack to track the state of each thread in the context.
+  typedef call_stack<thread_context, thread_info_base> thread_call_stack;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_THREAD_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/detail/thread_group.hpp b/subprojects/asio/include/asio/detail/thread_group.hpp
new file mode 100644
index 000000000..1e400b037
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/thread_group.hpp
@@ -0,0 +1,89 @@
+//
+// detail/thread_group.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_THREAD_GROUP_HPP
+#define ASIO_DETAIL_THREAD_GROUP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/detail/thread.hpp"
+
+namespace asio {
+namespace detail {
+
+class thread_group
+{
+public:
+  // Constructor initialises an empty thread group.
+  thread_group()
+    : first_(0)
+  {
+  }
+
+  // Destructor joins any remaining threads in the group.
+  ~thread_group()
+  {
+    join();
+  }
+
+  // Create a new thread in the group.
+  template <typename Function>
+  void create_thread(Function f)
+  {
+    first_ = new item(f, first_);
+  }
+
+  // Create new threads in the group.
+  template <typename Function>
+  void create_threads(Function f, std::size_t num_threads)
+  {
+    for (std::size_t i = 0; i < num_threads; ++i)
+      create_thread(f);
+  }
+
+  // Wait for all threads in the group to exit.
+  void join()
+  {
+    while (first_)
+    {
+      first_->thread_.join();
+      item* tmp = first_;
+      first_ = first_->next_;
+      delete tmp;
+    }
+  }
+
+private:
+  // Structure used to track a single thread in the group.
+  struct item
+  {
+    template <typename Function>
+    explicit item(Function f, item* next)
+      : thread_(f),
+        next_(next)
+    {
+    }
+
+    asio::detail::thread thread_;
+    item* next_;
+  };
+
+  // The first thread in the group.
+  item* first_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_THREAD_GROUP_HPP
diff --git a/subprojects/asio/include/asio/detail/thread_info_base.hpp b/subprojects/asio/include/asio/detail/thread_info_base.hpp
new file mode 100644
index 000000000..1b2220745
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/thread_info_base.hpp
@@ -0,0 +1,121 @@
+//
+// detail/thread_info_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_THREAD_INFO_BASE_HPP
+#define ASIO_DETAIL_THREAD_INFO_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <climits>
+#include <cstddef>
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class thread_info_base
+  : private noncopyable
+{
+public:
+  struct default_tag
+  {
+    enum { mem_index = 0 };
+  };
+
+  struct awaitee_tag
+  {
+    enum { mem_index = 1 };
+  };
+
+  thread_info_base()
+  {
+    for (int i = 0; i < max_mem_index; ++i)
+      reusable_memory_[i] = 0;
+  }
+
+  ~thread_info_base()
+  {
+    for (int i = 0; i < max_mem_index; ++i)
+      if (reusable_memory_[i])
+        ::operator delete(reusable_memory_[i]);
+  }
+
+  static void* allocate(thread_info_base* this_thread, std::size_t size)
+  {
+    return allocate(default_tag(), this_thread, size);
+  }
+
+  static void deallocate(thread_info_base* this_thread,
+      void* pointer, std::size_t size)
+  {
+    deallocate(default_tag(), this_thread, pointer, size);
+  }
+
+  template <typename Purpose>
+  static void* allocate(Purpose, thread_info_base* this_thread,
+      std::size_t size)
+  {
+    std::size_t chunks = (size + chunk_size - 1) / chunk_size;
+
+    if (this_thread && this_thread->reusable_memory_[Purpose::mem_index])
+    {
+      void* const pointer = this_thread->reusable_memory_[Purpose::mem_index];
+      this_thread->reusable_memory_[Purpose::mem_index] = 0;
+
+      unsigned char* const mem = static_cast<unsigned char*>(pointer);
+      if (static_cast<std::size_t>(mem[0]) >= chunks)
+      {
+        mem[size] = mem[0];
+        return pointer;
+      }
+
+      ::operator delete(pointer);
+    }
+
+    void* const pointer = ::operator new(chunks * chunk_size + 1);
+    unsigned char* const mem = static_cast<unsigned char*>(pointer);
+    mem[size] = (chunks <= UCHAR_MAX) ? static_cast<unsigned char>(chunks) : 0;
+    return pointer;
+  }
+
+  template <typename Purpose>
+  static void deallocate(Purpose, thread_info_base* this_thread,
+      void* pointer, std::size_t size)
+  {
+    if (size <= chunk_size * UCHAR_MAX)
+    {
+      if (this_thread && this_thread->reusable_memory_[Purpose::mem_index] == 0)
+      {
+        unsigned char* const mem = static_cast<unsigned char*>(pointer);
+        mem[0] = mem[size];
+        this_thread->reusable_memory_[Purpose::mem_index] = pointer;
+        return;
+      }
+    }
+
+    ::operator delete(pointer);
+  }
+
+private:
+  enum { chunk_size = 4 };
+  enum { max_mem_index = 2 };
+  void* reusable_memory_[max_mem_index];
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_THREAD_INFO_BASE_HPP
diff --git a/subprojects/asio/include/asio/detail/throw_error.hpp b/subprojects/asio/include/asio/detail/throw_error.hpp
new file mode 100644
index 000000000..5dd87855a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/throw_error.hpp
@@ -0,0 +1,53 @@
+//
+// detail/throw_error.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_THROW_ERROR_HPP
+#define ASIO_DETAIL_THROW_ERROR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/error_code.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+ASIO_DECL void do_throw_error(const asio::error_code& err);
+
+ASIO_DECL void do_throw_error(const asio::error_code& err,
+    const char* location);
+
+inline void throw_error(const asio::error_code& err)
+{
+  if (err)
+    do_throw_error(err);
+}
+
+inline void throw_error(const asio::error_code& err,
+    const char* location)
+{
+  if (err)
+    do_throw_error(err, location);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/throw_error.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_THROW_ERROR_HPP
diff --git a/subprojects/asio/include/asio/detail/throw_exception.hpp b/subprojects/asio/include/asio/detail/throw_exception.hpp
new file mode 100644
index 000000000..f9f7bfb9f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/throw_exception.hpp
@@ -0,0 +1,51 @@
+//
+// detail/throw_exception.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_THROW_EXCEPTION_HPP
+#define ASIO_DETAIL_THROW_EXCEPTION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_THROW_EXCEPTION)
+# include <boost/throw_exception.hpp>
+#endif // defined(ASIO_BOOST_THROW_EXCEPTION)
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_BOOST_THROW_EXCEPTION)
+using boost::throw_exception;
+#else // defined(ASIO_HAS_BOOST_THROW_EXCEPTION)
+
+// Declare the throw_exception function for all targets.
+template <typename Exception>
+void throw_exception(const Exception& e);
+
+// Only define the throw_exception function when exceptions are enabled.
+// Otherwise, it is up to the application to provide a definition of this
+// function.
+# if !defined(ASIO_NO_EXCEPTIONS)
+template <typename Exception>
+void throw_exception(const Exception& e)
+{
+  throw e;
+}
+# endif // !defined(ASIO_NO_EXCEPTIONS)
+
+#endif // defined(ASIO_HAS_BOOST_THROW_EXCEPTION)
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_THROW_EXCEPTION_HPP
diff --git a/subprojects/asio/include/asio/detail/timer_queue.hpp b/subprojects/asio/include/asio/detail/timer_queue.hpp
new file mode 100644
index 000000000..de37000db
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/timer_queue.hpp
@@ -0,0 +1,360 @@
+//
+// detail/timer_queue.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TIMER_QUEUE_HPP
+#define ASIO_DETAIL_TIMER_QUEUE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <vector>
+#include "asio/detail/cstdint.hpp"
+#include "asio/detail/date_time_fwd.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Time_Traits>
+class timer_queue
+  : public timer_queue_base
+{
+public:
+  // The time type.
+  typedef typename Time_Traits::time_type time_type;
+
+  // The duration type.
+  typedef typename Time_Traits::duration_type duration_type;
+
+  // Per-timer data.
+  class per_timer_data
+  {
+  public:
+    per_timer_data() :
+      heap_index_((std::numeric_limits<std::size_t>::max)()),
+      next_(0), prev_(0)
+    {
+    }
+
+  private:
+    friend class timer_queue;
+
+    // The operations waiting on the timer.
+    op_queue<wait_op> op_queue_;
+
+    // The index of the timer in the heap.
+    std::size_t heap_index_;
+
+    // Pointers to adjacent timers in a linked list.
+    per_timer_data* next_;
+    per_timer_data* prev_;
+  };
+
+  // Constructor.
+  timer_queue()
+    : timers_(),
+      heap_()
+  {
+  }
+
+  // Add a new timer to the queue. Returns true if this is the timer that is
+  // earliest in the queue, in which case the reactor's event demultiplexing
+  // function call may need to be interrupted and restarted.
+  bool enqueue_timer(const time_type& time, per_timer_data& timer, wait_op* op)
+  {
+    // Enqueue the timer object.
+    if (timer.prev_ == 0 && &timer != timers_)
+    {
+      if (this->is_positive_infinity(time))
+      {
+        // No heap entry is required for timers that never expire.
+        timer.heap_index_ = (std::numeric_limits<std::size_t>::max)();
+      }
+      else
+      {
+        // Put the new timer at the correct position in the heap. This is done
+        // first since push_back() can throw due to allocation failure.
+        timer.heap_index_ = heap_.size();
+        heap_entry entry = { time, &timer };
+        heap_.push_back(entry);
+        up_heap(heap_.size() - 1);
+      }
+
+      // Insert the new timer into the linked list of active timers.
+      timer.next_ = timers_;
+      timer.prev_ = 0;
+      if (timers_)
+        timers_->prev_ = &timer;
+      timers_ = &timer;
+    }
+
+    // Enqueue the individual timer operation.
+    timer.op_queue_.push(op);
+
+    // Interrupt reactor only if newly added timer is first to expire.
+    return timer.heap_index_ == 0 && timer.op_queue_.front() == op;
+  }
+
+  // Whether there are no timers in the queue.
+  virtual bool empty() const
+  {
+    return timers_ == 0;
+  }
+
+  // Get the time for the timer that is earliest in the queue.
+  virtual long wait_duration_msec(long max_duration) const
+  {
+    if (heap_.empty())
+      return max_duration;
+
+    return this->to_msec(
+        Time_Traits::to_posix_duration(
+          Time_Traits::subtract(heap_[0].time_, Time_Traits::now())),
+        max_duration);
+  }
+
+  // Get the time for the timer that is earliest in the queue.
+  virtual long wait_duration_usec(long max_duration) const
+  {
+    if (heap_.empty())
+      return max_duration;
+
+    return this->to_usec(
+        Time_Traits::to_posix_duration(
+          Time_Traits::subtract(heap_[0].time_, Time_Traits::now())),
+        max_duration);
+  }
+
+  // Dequeue all timers not later than the current time.
+  virtual void get_ready_timers(op_queue<operation>& ops)
+  {
+    if (!heap_.empty())
+    {
+      const time_type now = Time_Traits::now();
+      while (!heap_.empty() && !Time_Traits::less_than(now, heap_[0].time_))
+      {
+        per_timer_data* timer = heap_[0].timer_;
+        ops.push(timer->op_queue_);
+        remove_timer(*timer);
+      }
+    }
+  }
+
+  // Dequeue all timers.
+  virtual void get_all_timers(op_queue<operation>& ops)
+  {
+    while (timers_)
+    {
+      per_timer_data* timer = timers_;
+      timers_ = timers_->next_;
+      ops.push(timer->op_queue_);
+      timer->next_ = 0;
+      timer->prev_ = 0;
+    }
+
+    heap_.clear();
+  }
+
+  // Cancel and dequeue operations for the given timer.
+  std::size_t cancel_timer(per_timer_data& timer, op_queue<operation>& ops,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)())
+  {
+    std::size_t num_cancelled = 0;
+    if (timer.prev_ != 0 || &timer == timers_)
+    {
+      while (wait_op* op = (num_cancelled != max_cancelled)
+          ? timer.op_queue_.front() : 0)
+      {
+        op->ec_ = asio::error::operation_aborted;
+        timer.op_queue_.pop();
+        ops.push(op);
+        ++num_cancelled;
+      }
+      if (timer.op_queue_.empty())
+        remove_timer(timer);
+    }
+    return num_cancelled;
+  }
+
+  // Move operations from one timer to another, empty timer.
+  void move_timer(per_timer_data& target, per_timer_data& source)
+  {
+    target.op_queue_.push(source.op_queue_);
+
+    target.heap_index_ = source.heap_index_;
+    source.heap_index_ = (std::numeric_limits<std::size_t>::max)();
+
+    if (target.heap_index_ < heap_.size())
+      heap_[target.heap_index_].timer_ = &target;
+
+    if (timers_ == &source)
+      timers_ = &target;
+    if (source.prev_)
+      source.prev_->next_ = &target;
+    if (source.next_)
+      source.next_->prev_= &target;
+    target.next_ = source.next_;
+    target.prev_ = source.prev_;
+    source.next_ = 0;
+    source.prev_ = 0;
+  }
+
+private:
+  // Move the item at the given index up the heap to its correct position.
+  void up_heap(std::size_t index)
+  {
+    while (index > 0)
+    {
+      std::size_t parent = (index - 1) / 2;
+      if (!Time_Traits::less_than(heap_[index].time_, heap_[parent].time_))
+        break;
+      swap_heap(index, parent);
+      index = parent;
+    }
+  }
+
+  // Move the item at the given index down the heap to its correct position.
+  void down_heap(std::size_t index)
+  {
+    std::size_t child = index * 2 + 1;
+    while (child < heap_.size())
+    {
+      std::size_t min_child = (child + 1 == heap_.size()
+          || Time_Traits::less_than(
+            heap_[child].time_, heap_[child + 1].time_))
+        ? child : child + 1;
+      if (Time_Traits::less_than(heap_[index].time_, heap_[min_child].time_))
+        break;
+      swap_heap(index, min_child);
+      index = min_child;
+      child = index * 2 + 1;
+    }
+  }
+
+  // Swap two entries in the heap.
+  void swap_heap(std::size_t index1, std::size_t index2)
+  {
+    heap_entry tmp = heap_[index1];
+    heap_[index1] = heap_[index2];
+    heap_[index2] = tmp;
+    heap_[index1].timer_->heap_index_ = index1;
+    heap_[index2].timer_->heap_index_ = index2;
+  }
+
+  // Remove a timer from the heap and list of timers.
+  void remove_timer(per_timer_data& timer)
+  {
+    // Remove the timer from the heap.
+    std::size_t index = timer.heap_index_;
+    if (!heap_.empty() && index < heap_.size())
+    {
+      if (index == heap_.size() - 1)
+      {
+        timer.heap_index_ = (std::numeric_limits<std::size_t>::max)();
+        heap_.pop_back();
+      }
+      else
+      {
+        swap_heap(index, heap_.size() - 1);
+        timer.heap_index_ = (std::numeric_limits<std::size_t>::max)();
+        heap_.pop_back();
+        if (index > 0 && Time_Traits::less_than(
+              heap_[index].time_, heap_[(index - 1) / 2].time_))
+          up_heap(index);
+        else
+          down_heap(index);
+      }
+    }
+
+    // Remove the timer from the linked list of active timers.
+    if (timers_ == &timer)
+      timers_ = timer.next_;
+    if (timer.prev_)
+      timer.prev_->next_ = timer.next_;
+    if (timer.next_)
+      timer.next_->prev_= timer.prev_;
+    timer.next_ = 0;
+    timer.prev_ = 0;
+  }
+
+  // Determine if the specified absolute time is positive infinity.
+  template <typename Time_Type>
+  static bool is_positive_infinity(const Time_Type&)
+  {
+    return false;
+  }
+
+  // Determine if the specified absolute time is positive infinity.
+  template <typename T, typename TimeSystem>
+  static bool is_positive_infinity(
+      const boost::date_time::base_time<T, TimeSystem>& time)
+  {
+    return time.is_pos_infinity();
+  }
+
+  // Helper function to convert a duration into milliseconds.
+  template <typename Duration>
+  long to_msec(const Duration& d, long max_duration) const
+  {
+    if (d.ticks() <= 0)
+      return 0;
+    int64_t msec = d.total_milliseconds();
+    if (msec == 0)
+      return 1;
+    if (msec > max_duration)
+      return max_duration;
+    return static_cast<long>(msec);
+  }
+
+  // Helper function to convert a duration into microseconds.
+  template <typename Duration>
+  long to_usec(const Duration& d, long max_duration) const
+  {
+    if (d.ticks() <= 0)
+      return 0;
+    int64_t usec = d.total_microseconds();
+    if (usec == 0)
+      return 1;
+    if (usec > max_duration)
+      return max_duration;
+    return static_cast<long>(usec);
+  }
+
+  // The head of a linked list of all active timers.
+  per_timer_data* timers_;
+
+  struct heap_entry
+  {
+    // The time when the timer should fire.
+    time_type time_;
+
+    // The associated timer with enqueued operations.
+    per_timer_data* timer_;
+  };
+
+  // The heap of timers, with the earliest timer at the front.
+  std::vector<heap_entry> heap_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_TIMER_QUEUE_HPP
diff --git a/subprojects/asio/include/asio/detail/timer_queue_base.hpp b/subprojects/asio/include/asio/detail/timer_queue_base.hpp
new file mode 100644
index 000000000..4af995f23
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/timer_queue_base.hpp
@@ -0,0 +1,68 @@
+//
+// detail/timer_queue_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TIMER_QUEUE_BASE_HPP
+#define ASIO_DETAIL_TIMER_QUEUE_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class timer_queue_base
+  : private noncopyable
+{
+public:
+  // Constructor.
+  timer_queue_base() : next_(0) {}
+
+  // Destructor.
+  virtual ~timer_queue_base() {}
+
+  // Whether there are no timers in the queue.
+  virtual bool empty() const = 0;
+
+  // Get the time to wait until the next timer.
+  virtual long wait_duration_msec(long max_duration) const = 0;
+
+  // Get the time to wait until the next timer.
+  virtual long wait_duration_usec(long max_duration) const = 0;
+
+  // Dequeue all ready timers.
+  virtual void get_ready_timers(op_queue<operation>& ops) = 0;
+
+  // Dequeue all timers.
+  virtual void get_all_timers(op_queue<operation>& ops) = 0;
+
+private:
+  friend class timer_queue_set;
+
+  // Next timer queue in the set.
+  timer_queue_base* next_;
+};
+
+template <typename Time_Traits>
+class timer_queue;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_TIMER_QUEUE_BASE_HPP
diff --git a/subprojects/asio/include/asio/detail/timer_queue_ptime.hpp b/subprojects/asio/include/asio/detail/timer_queue_ptime.hpp
new file mode 100644
index 000000000..84e83385e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/timer_queue_ptime.hpp
@@ -0,0 +1,99 @@
+//
+// detail/timer_queue_ptime.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TIMER_QUEUE_PTIME_HPP
+#define ASIO_DETAIL_TIMER_QUEUE_PTIME_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#include "asio/time_traits.hpp"
+#include "asio/detail/timer_queue.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct forwarding_posix_time_traits : time_traits<boost::posix_time::ptime> {};
+
+// Template specialisation for the commonly used instantation.
+template <>
+class timer_queue<time_traits<boost::posix_time::ptime> >
+  : public timer_queue_base
+{
+public:
+  // The time type.
+  typedef boost::posix_time::ptime time_type;
+
+  // The duration type.
+  typedef boost::posix_time::time_duration duration_type;
+
+  // Per-timer data.
+  typedef timer_queue<forwarding_posix_time_traits>::per_timer_data
+    per_timer_data;
+
+  // Constructor.
+  ASIO_DECL timer_queue();
+
+  // Destructor.
+  ASIO_DECL virtual ~timer_queue();
+
+  // Add a new timer to the queue. Returns true if this is the timer that is
+  // earliest in the queue, in which case the reactor's event demultiplexing
+  // function call may need to be interrupted and restarted.
+  ASIO_DECL bool enqueue_timer(const time_type& time,
+      per_timer_data& timer, wait_op* op);
+
+  // Whether there are no timers in the queue.
+  ASIO_DECL virtual bool empty() const;
+
+  // Get the time for the timer that is earliest in the queue.
+  ASIO_DECL virtual long wait_duration_msec(long max_duration) const;
+
+  // Get the time for the timer that is earliest in the queue.
+  ASIO_DECL virtual long wait_duration_usec(long max_duration) const;
+
+  // Dequeue all timers not later than the current time.
+  ASIO_DECL virtual void get_ready_timers(op_queue<operation>& ops);
+
+  // Dequeue all timers.
+  ASIO_DECL virtual void get_all_timers(op_queue<operation>& ops);
+
+  // Cancel and dequeue operations for the given timer.
+  ASIO_DECL std::size_t cancel_timer(
+      per_timer_data& timer, op_queue<operation>& ops,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
+
+  // Move operations from one timer to another, empty timer.
+  ASIO_DECL void move_timer(per_timer_data& target,
+      per_timer_data& source);
+
+private:
+  timer_queue<forwarding_posix_time_traits> impl_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/timer_queue_ptime.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#endif // ASIO_DETAIL_TIMER_QUEUE_PTIME_HPP
diff --git a/subprojects/asio/include/asio/detail/timer_queue_set.hpp b/subprojects/asio/include/asio/detail/timer_queue_set.hpp
new file mode 100644
index 000000000..0ea372ae5
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/timer_queue_set.hpp
@@ -0,0 +1,66 @@
+//
+// detail/timer_queue_set.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TIMER_QUEUE_SET_HPP
+#define ASIO_DETAIL_TIMER_QUEUE_SET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class timer_queue_set
+{
+public:
+  // Constructor.
+  ASIO_DECL timer_queue_set();
+
+  // Add a timer queue to the set.
+  ASIO_DECL void insert(timer_queue_base* q);
+
+  // Remove a timer queue from the set.
+  ASIO_DECL void erase(timer_queue_base* q);
+
+  // Determine whether all queues are empty.
+  ASIO_DECL bool all_empty() const;
+
+  // Get the wait duration in milliseconds.
+  ASIO_DECL long wait_duration_msec(long max_duration) const;
+
+  // Get the wait duration in microseconds.
+  ASIO_DECL long wait_duration_usec(long max_duration) const;
+
+  // Dequeue all ready timers.
+  ASIO_DECL void get_ready_timers(op_queue<operation>& ops);
+
+  // Dequeue all timers.
+  ASIO_DECL void get_all_timers(op_queue<operation>& ops);
+
+private:
+  timer_queue_base* first_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/timer_queue_set.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_DETAIL_TIMER_QUEUE_SET_HPP
diff --git a/subprojects/asio/include/asio/detail/timer_scheduler.hpp b/subprojects/asio/include/asio/detail/timer_scheduler.hpp
new file mode 100644
index 000000000..b1f8df45d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/timer_scheduler.hpp
@@ -0,0 +1,35 @@
+//
+// detail/timer_scheduler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TIMER_SCHEDULER_HPP
+#define ASIO_DETAIL_TIMER_SCHEDULER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/timer_scheduler_fwd.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/winrt_timer_scheduler.hpp"
+#elif defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_io_context.hpp"
+#elif defined(ASIO_HAS_EPOLL)
+# include "asio/detail/epoll_reactor.hpp"
+#elif defined(ASIO_HAS_KQUEUE)
+# include "asio/detail/kqueue_reactor.hpp"
+#elif defined(ASIO_HAS_DEV_POLL)
+# include "asio/detail/dev_poll_reactor.hpp"
+#else
+# include "asio/detail/select_reactor.hpp"
+#endif
+
+#endif // ASIO_DETAIL_TIMER_SCHEDULER_HPP
diff --git a/subprojects/asio/include/asio/detail/timer_scheduler_fwd.hpp b/subprojects/asio/include/asio/detail/timer_scheduler_fwd.hpp
new file mode 100644
index 000000000..80bae5034
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/timer_scheduler_fwd.hpp
@@ -0,0 +1,40 @@
+//
+// detail/timer_scheduler_fwd.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TIMER_SCHEDULER_FWD_HPP
+#define ASIO_DETAIL_TIMER_SCHEDULER_FWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+typedef class winrt_timer_scheduler timer_scheduler;
+#elif defined(ASIO_HAS_IOCP)
+typedef class win_iocp_io_context timer_scheduler;
+#elif defined(ASIO_HAS_EPOLL)
+typedef class epoll_reactor timer_scheduler;
+#elif defined(ASIO_HAS_KQUEUE)
+typedef class kqueue_reactor timer_scheduler;
+#elif defined(ASIO_HAS_DEV_POLL)
+typedef class dev_poll_reactor timer_scheduler;
+#else
+typedef class select_reactor timer_scheduler;
+#endif
+
+} // namespace detail
+} // namespace asio
+
+#endif // ASIO_DETAIL_TIMER_SCHEDULER_FWD_HPP
diff --git a/subprojects/asio/include/asio/detail/tss_ptr.hpp b/subprojects/asio/include/asio/detail/tss_ptr.hpp
new file mode 100644
index 000000000..e628abe9d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/tss_ptr.hpp
@@ -0,0 +1,69 @@
+//
+// detail/tss_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TSS_PTR_HPP
+#define ASIO_DETAIL_TSS_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_THREADS)
+# include "asio/detail/null_tss_ptr.hpp"
+#elif defined(ASIO_HAS_THREAD_KEYWORD_EXTENSION)
+# include "asio/detail/keyword_tss_ptr.hpp"
+#elif defined(ASIO_WINDOWS)
+# include "asio/detail/win_tss_ptr.hpp"
+#elif defined(ASIO_HAS_PTHREADS)
+# include "asio/detail/posix_tss_ptr.hpp"
+#else
+# error Only Windows and POSIX are supported!
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+class tss_ptr
+#if !defined(ASIO_HAS_THREADS)
+  : public null_tss_ptr<T>
+#elif defined(ASIO_HAS_THREAD_KEYWORD_EXTENSION)
+  : public keyword_tss_ptr<T>
+#elif defined(ASIO_WINDOWS)
+  : public win_tss_ptr<T>
+#elif defined(ASIO_HAS_PTHREADS)
+  : public posix_tss_ptr<T>
+#endif
+{
+public:
+  void operator=(T* value)
+  {
+#if !defined(ASIO_HAS_THREADS)
+    null_tss_ptr<T>::operator=(value);
+#elif defined(ASIO_HAS_THREAD_KEYWORD_EXTENSION)
+    keyword_tss_ptr<T>::operator=(value);
+#elif defined(ASIO_WINDOWS)
+    win_tss_ptr<T>::operator=(value);
+#elif defined(ASIO_HAS_PTHREADS)
+    posix_tss_ptr<T>::operator=(value);
+#endif
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_TSS_PTR_HPP
diff --git a/subprojects/asio/include/asio/detail/type_traits.hpp b/subprojects/asio/include/asio/detail/type_traits.hpp
new file mode 100644
index 000000000..edf09281a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/type_traits.hpp
@@ -0,0 +1,86 @@
+//
+// detail/type_traits.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_TYPE_TRAITS_HPP
+#define ASIO_DETAIL_TYPE_TRAITS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_TYPE_TRAITS)
+# include <type_traits>
+#else // defined(ASIO_HAS_TYPE_TRAITS)
+# include <boost/type_traits/add_const.hpp>
+# include <boost/type_traits/conditional.hpp>
+# include <boost/type_traits/decay.hpp>
+# include <boost/type_traits/integral_constant.hpp>
+# include <boost/type_traits/is_base_of.hpp>
+# include <boost/type_traits/is_class.hpp>
+# include <boost/type_traits/is_const.hpp>
+# include <boost/type_traits/is_convertible.hpp>
+# include <boost/type_traits/is_function.hpp>
+# include <boost/type_traits/is_same.hpp>
+# include <boost/type_traits/remove_pointer.hpp>
+# include <boost/type_traits/remove_reference.hpp>
+# include <boost/utility/enable_if.hpp>
+# include <boost/utility/result_of.hpp>
+#endif // defined(ASIO_HAS_TYPE_TRAITS)
+
+namespace asio {
+
+#if defined(ASIO_HAS_STD_TYPE_TRAITS)
+using std::add_const;
+using std::conditional;
+using std::decay;
+using std::enable_if;
+using std::false_type;
+using std::integral_constant;
+using std::is_base_of;
+using std::is_class;
+using std::is_const;
+using std::is_convertible;
+using std::is_function;
+using std::is_same;
+using std::remove_pointer;
+using std::remove_reference;
+#if defined(ASIO_HAS_STD_INVOKE_RESULT)
+template <typename> struct result_of;
+template <typename F, typename... Args>
+struct result_of<F(Args...)> : std::invoke_result<F, Args...> {};
+#else // defined(ASIO_HAS_STD_INVOKE_RESULT)
+using std::result_of;
+#endif // defined(ASIO_HAS_STD_INVOKE_RESULT)
+using std::true_type;
+#else // defined(ASIO_HAS_STD_TYPE_TRAITS)
+using boost::add_const;
+template <bool Condition, typename Type = void>
+struct enable_if : boost::enable_if_c<Condition, Type> {};
+using boost::conditional;
+using boost::decay;
+using boost::false_type;
+using boost::integral_constant;
+using boost::is_base_of;
+using boost::is_class;
+using boost::is_const;
+using boost::is_convertible;
+using boost::is_function;
+using boost::is_same;
+using boost::remove_pointer;
+using boost::remove_reference;
+using boost::result_of;
+using boost::true_type;
+#endif // defined(ASIO_HAS_STD_TYPE_TRAITS)
+
+} // namespace asio
+
+#endif // ASIO_DETAIL_TYPE_TRAITS_HPP
diff --git a/subprojects/asio/include/asio/detail/variadic_templates.hpp b/subprojects/asio/include/asio/detail/variadic_templates.hpp
new file mode 100644
index 000000000..d54eb4e4b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/variadic_templates.hpp
@@ -0,0 +1,119 @@
+//
+// detail/variadic_templates.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_VARIADIC_TEMPLATES_HPP
+#define ASIO_DETAIL_VARIADIC_TEMPLATES_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+# define ASIO_VARIADIC_TPARAMS(n) ASIO_VARIADIC_TPARAMS_##n
+
+# define ASIO_VARIADIC_TPARAMS_1 \
+  typename T1
+# define ASIO_VARIADIC_TPARAMS_2 \
+  typename T1, typename T2
+# define ASIO_VARIADIC_TPARAMS_3 \
+  typename T1, typename T2, typename T3
+# define ASIO_VARIADIC_TPARAMS_4 \
+  typename T1, typename T2, typename T3, typename T4
+# define ASIO_VARIADIC_TPARAMS_5 \
+  typename T1, typename T2, typename T3, typename T4, typename T5
+
+# define ASIO_VARIADIC_TARGS(n) ASIO_VARIADIC_TARGS_##n
+
+# define ASIO_VARIADIC_TARGS_1 T1
+# define ASIO_VARIADIC_TARGS_2 T1, T2
+# define ASIO_VARIADIC_TARGS_3 T1, T2, T3
+# define ASIO_VARIADIC_TARGS_4 T1, T2, T3, T4
+# define ASIO_VARIADIC_TARGS_5 T1, T2, T3, T4, T5
+
+# define ASIO_VARIADIC_BYVAL_PARAMS(n) \
+  ASIO_VARIADIC_BYVAL_PARAMS_##n
+
+# define ASIO_VARIADIC_BYVAL_PARAMS_1 T1 x1
+# define ASIO_VARIADIC_BYVAL_PARAMS_2 T1 x1, T2 x2
+# define ASIO_VARIADIC_BYVAL_PARAMS_3 T1 x1, T2 x2, T3 x3
+# define ASIO_VARIADIC_BYVAL_PARAMS_4 T1 x1, T2 x2, T3 x3, T4 x4
+# define ASIO_VARIADIC_BYVAL_PARAMS_5 T1 x1, T2 x2, T3 x3, T4 x4, T5 x5
+
+# define ASIO_VARIADIC_BYVAL_ARGS(n) \
+  ASIO_VARIADIC_BYVAL_ARGS_##n
+
+# define ASIO_VARIADIC_BYVAL_ARGS_1 x1
+# define ASIO_VARIADIC_BYVAL_ARGS_2 x1, x2
+# define ASIO_VARIADIC_BYVAL_ARGS_3 x1, x2, x3
+# define ASIO_VARIADIC_BYVAL_ARGS_4 x1, x2, x3, x4
+# define ASIO_VARIADIC_BYVAL_ARGS_5 x1, x2, x3, x4, x5
+
+# define ASIO_VARIADIC_MOVE_PARAMS(n) \
+  ASIO_VARIADIC_MOVE_PARAMS_##n
+
+# define ASIO_VARIADIC_MOVE_PARAMS_1 \
+  ASIO_MOVE_ARG(T1) x1
+# define ASIO_VARIADIC_MOVE_PARAMS_2 \
+  ASIO_MOVE_ARG(T1) x1, ASIO_MOVE_ARG(T2) x2
+# define ASIO_VARIADIC_MOVE_PARAMS_3 \
+  ASIO_MOVE_ARG(T1) x1, ASIO_MOVE_ARG(T2) x2, \
+  ASIO_MOVE_ARG(T3) x3
+# define ASIO_VARIADIC_MOVE_PARAMS_4 \
+  ASIO_MOVE_ARG(T1) x1, ASIO_MOVE_ARG(T2) x2, \
+  ASIO_MOVE_ARG(T3) x3, ASIO_MOVE_ARG(T4) x4
+# define ASIO_VARIADIC_MOVE_PARAMS_5 \
+  ASIO_MOVE_ARG(T1) x1, ASIO_MOVE_ARG(T2) x2, \
+  ASIO_MOVE_ARG(T3) x3, ASIO_MOVE_ARG(T4) x4, \
+  ASIO_MOVE_ARG(T5) x5
+
+# define ASIO_VARIADIC_MOVE_ARGS(n) \
+  ASIO_VARIADIC_MOVE_ARGS_##n
+
+# define ASIO_VARIADIC_MOVE_ARGS_1 \
+  ASIO_MOVE_CAST(T1)(x1)
+# define ASIO_VARIADIC_MOVE_ARGS_2 \
+  ASIO_MOVE_CAST(T1)(x1), ASIO_MOVE_CAST(T2)(x2)
+# define ASIO_VARIADIC_MOVE_ARGS_3 \
+  ASIO_MOVE_CAST(T1)(x1), ASIO_MOVE_CAST(T2)(x2), \
+  ASIO_MOVE_CAST(T3)(x3)
+# define ASIO_VARIADIC_MOVE_ARGS_4 \
+  ASIO_MOVE_CAST(T1)(x1), ASIO_MOVE_CAST(T2)(x2), \
+  ASIO_MOVE_CAST(T3)(x3), ASIO_MOVE_CAST(T4)(x4)
+# define ASIO_VARIADIC_MOVE_ARGS_5 \
+  ASIO_MOVE_CAST(T1)(x1), ASIO_MOVE_CAST(T2)(x2), \
+  ASIO_MOVE_CAST(T3)(x3), ASIO_MOVE_CAST(T4)(x4), \
+  ASIO_MOVE_CAST(T5)(x5)
+
+# define ASIO_VARIADIC_DECAY(n) \
+  ASIO_VARIADIC_DECAY_##n
+
+# define ASIO_VARIADIC_DECAY_1 \
+  typename decay<T1>::type
+# define ASIO_VARIADIC_DECAY_2 \
+  typename decay<T1>::type, typename decay<T2>::type
+# define ASIO_VARIADIC_DECAY_3 \
+  typename decay<T1>::type, typename decay<T2>::type, \
+  typename decay<T3>::type
+# define ASIO_VARIADIC_DECAY_4 \
+  typename decay<T1>::type, typename decay<T2>::type, \
+  typename decay<T3>::type, typename decay<T4>::type
+# define ASIO_VARIADIC_DECAY_5 \
+  typename decay<T1>::type, typename decay<T2>::type, \
+  typename decay<T3>::type, typename decay<T4>::type, \
+  typename decay<T5>::type
+
+# define ASIO_VARIADIC_GENERATE(m) m(1) m(2) m(3) m(4) m(5)
+
+#endif // !defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#endif // ASIO_DETAIL_VARIADIC_TEMPLATES_HPP
diff --git a/subprojects/asio/include/asio/detail/wait_handler.hpp b/subprojects/asio/include/asio/detail/wait_handler.hpp
new file mode 100644
index 000000000..bd3dc2441
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/wait_handler.hpp
@@ -0,0 +1,85 @@
+//
+// detail/wait_handler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WAIT_HANDLER_HPP
+#define ASIO_DETAIL_WAIT_HANDLER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class wait_handler : public wait_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(wait_handler);
+
+  wait_handler(Handler& h)
+    : wait_op(&wait_handler::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(h))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& /*ec*/,
+      std::size_t /*bytes_transferred*/)
+  {
+    // Take ownership of the handler object.
+    wait_handler* h(static_cast<wait_handler*>(base));
+    ptr p = { asio::detail::addressof(h->handler_), h, h };
+    handler_work<Handler> w(h->handler_);
+
+    ASIO_HANDLER_COMPLETION((*h));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(h->handler_, h->ec_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WAIT_HANDLER_HPP
diff --git a/subprojects/asio/include/asio/detail/wait_op.hpp b/subprojects/asio/include/asio/detail/wait_op.hpp
new file mode 100644
index 000000000..1a3017bae
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/wait_op.hpp
@@ -0,0 +1,45 @@
+//
+// detail/wait_op.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WAIT_OP_HPP
+#define ASIO_DETAIL_WAIT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class wait_op
+  : public operation
+{
+public:
+  // The error code to be passed to the completion handler.
+  asio::error_code ec_;
+
+protected:
+  wait_op(func_type func)
+    : operation(func)
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WAIT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_event.hpp b/subprojects/asio/include/asio/detail/win_event.hpp
new file mode 100644
index 000000000..859cdee7b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_event.hpp
@@ -0,0 +1,151 @@
+//
+// detail/win_event.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_EVENT_HPP
+#define ASIO_DETAIL_WIN_EVENT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include "asio/detail/assert.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_event
+  : private noncopyable
+{
+public:
+  // Constructor.
+  ASIO_DECL win_event();
+
+  // Destructor.
+  ASIO_DECL ~win_event();
+
+  // Signal the event. (Retained for backward compatibility.)
+  template <typename Lock>
+  void signal(Lock& lock)
+  {
+    this->signal_all(lock);
+  }
+
+  // Signal all waiters.
+  template <typename Lock>
+  void signal_all(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    (void)lock;
+    state_ |= 1;
+    ::SetEvent(events_[0]);
+  }
+
+  // Unlock the mutex and signal one waiter.
+  template <typename Lock>
+  void unlock_and_signal_one(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    state_ |= 1;
+    bool have_waiters = (state_ > 1);
+    lock.unlock();
+    if (have_waiters)
+      ::SetEvent(events_[1]);
+  }
+
+  // If there's a waiter, unlock the mutex and signal it.
+  template <typename Lock>
+  bool maybe_unlock_and_signal_one(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    state_ |= 1;
+    if (state_ > 1)
+    {
+      lock.unlock();
+      ::SetEvent(events_[1]);
+      return true;
+    }
+    return false;
+  }
+
+  // Reset the event.
+  template <typename Lock>
+  void clear(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    (void)lock;
+    ::ResetEvent(events_[0]);
+    state_ &= ~std::size_t(1);
+  }
+
+  // Wait for the event to become signalled.
+  template <typename Lock>
+  void wait(Lock& lock)
+  {
+    ASIO_ASSERT(lock.locked());
+    while ((state_ & 1) == 0)
+    {
+      state_ += 2;
+      lock.unlock();
+#if defined(ASIO_WINDOWS_APP)
+      ::WaitForMultipleObjectsEx(2, events_, false, INFINITE, false);
+#else // defined(ASIO_WINDOWS_APP)
+      ::WaitForMultipleObjects(2, events_, false, INFINITE);
+#endif // defined(ASIO_WINDOWS_APP)
+      lock.lock();
+      state_ -= 2;
+    }
+  }
+
+  // Timed wait for the event to become signalled.
+  template <typename Lock>
+  bool wait_for_usec(Lock& lock, long usec)
+  {
+    ASIO_ASSERT(lock.locked());
+    if ((state_ & 1) == 0)
+    {
+      state_ += 2;
+      lock.unlock();
+      DWORD msec = usec > 0 ? (usec < 1000 ? 1 : usec / 1000) : 0;
+#if defined(ASIO_WINDOWS_APP)
+      ::WaitForMultipleObjectsEx(2, events_, false, msec, false);
+#else // defined(ASIO_WINDOWS_APP)
+      ::WaitForMultipleObjects(2, events_, false, msec);
+#endif // defined(ASIO_WINDOWS_APP)
+      lock.lock();
+      state_ -= 2;
+    }
+    return (state_ & 1) != 0;
+  }
+
+private:
+  HANDLE events_[2];
+  std::size_t state_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_event.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_WIN_EVENT_HPP
diff --git a/subprojects/asio/include/asio/detail/win_fd_set_adapter.hpp b/subprojects/asio/include/asio/detail/win_fd_set_adapter.hpp
new file mode 100644
index 000000000..8d5e700e2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_fd_set_adapter.hpp
@@ -0,0 +1,149 @@
+//
+// detail/win_fd_set_adapter.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_FD_SET_ADAPTER_HPP
+#define ASIO_DETAIL_WIN_FD_SET_ADAPTER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/reactor_op_queue.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Adapts the FD_SET type to meet the Descriptor_Set concept's requirements.
+class win_fd_set_adapter : noncopyable
+{
+public:
+  enum { default_fd_set_size = 1024 };
+
+  win_fd_set_adapter()
+    : capacity_(default_fd_set_size),
+      max_descriptor_(invalid_socket)
+  {
+    fd_set_ = static_cast<win_fd_set*>(::operator new(
+          sizeof(win_fd_set) - sizeof(SOCKET)
+          + sizeof(SOCKET) * (capacity_)));
+    fd_set_->fd_count = 0;
+  }
+
+  ~win_fd_set_adapter()
+  {
+    ::operator delete(fd_set_);
+  }
+
+  void reset()
+  {
+    fd_set_->fd_count = 0;
+    max_descriptor_ = invalid_socket;
+  }
+
+  bool set(socket_type descriptor)
+  {
+    for (u_int i = 0; i < fd_set_->fd_count; ++i)
+      if (fd_set_->fd_array[i] == descriptor)
+        return true;
+
+    reserve(fd_set_->fd_count + 1);
+    fd_set_->fd_array[fd_set_->fd_count++] = descriptor;
+    return true;
+  }
+
+  void set(reactor_op_queue<socket_type>& operations, op_queue<operation>&)
+  {
+    reactor_op_queue<socket_type>::iterator i = operations.begin();
+    while (i != operations.end())
+    {
+      reactor_op_queue<socket_type>::iterator op_iter = i++;
+      reserve(fd_set_->fd_count + 1);
+      fd_set_->fd_array[fd_set_->fd_count++] = op_iter->first;
+    }
+  }
+
+  bool is_set(socket_type descriptor) const
+  {
+    return !!__WSAFDIsSet(descriptor,
+        const_cast<fd_set*>(reinterpret_cast<const fd_set*>(fd_set_)));
+  }
+
+  operator fd_set*()
+  {
+    return reinterpret_cast<fd_set*>(fd_set_);
+  }
+
+  socket_type max_descriptor() const
+  {
+    return max_descriptor_;
+  }
+
+  void perform(reactor_op_queue<socket_type>& operations,
+      op_queue<operation>& ops) const
+  {
+    for (u_int i = 0; i < fd_set_->fd_count; ++i)
+      operations.perform_operations(fd_set_->fd_array[i], ops);
+  }
+
+private:
+  // This structure is defined to be compatible with the Windows API fd_set
+  // structure, but without being dependent on the value of FD_SETSIZE. We use
+  // the "struct hack" to allow the number of descriptors to be varied at
+  // runtime.
+  struct win_fd_set
+  {
+    u_int fd_count;
+    SOCKET fd_array[1];
+  };
+
+  // Increase the fd_set_ capacity to at least the specified number of elements.
+  void reserve(u_int n)
+  {
+    if (n <= capacity_)
+      return;
+
+    u_int new_capacity = capacity_ + capacity_ / 2;
+    if (new_capacity < n)
+      new_capacity = n;
+
+    win_fd_set* new_fd_set = static_cast<win_fd_set*>(::operator new(
+          sizeof(win_fd_set) - sizeof(SOCKET)
+          + sizeof(SOCKET) * (new_capacity)));
+
+    new_fd_set->fd_count = fd_set_->fd_count;
+    for (u_int i = 0; i < fd_set_->fd_count; ++i)
+      new_fd_set->fd_array[i] = fd_set_->fd_array[i];
+
+    ::operator delete(fd_set_);
+    fd_set_ = new_fd_set;
+    capacity_ = new_capacity;
+  }
+
+  win_fd_set* fd_set_;
+  u_int capacity_;
+  socket_type max_descriptor_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_WIN_FD_SET_ADAPTER_HPP
diff --git a/subprojects/asio/include/asio/detail/win_fenced_block.hpp b/subprojects/asio/include/asio/detail/win_fenced_block.hpp
new file mode 100644
index 000000000..1ce6e13b9
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_fenced_block.hpp
@@ -0,0 +1,90 @@
+//
+// detail/win_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_WIN_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) && !defined(UNDER_CE)
+
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/noncopyable.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_fenced_block
+  : private noncopyable
+{
+public:
+  enum half_t { half };
+  enum full_t { full };
+
+  // Constructor for a half fenced block.
+  explicit win_fenced_block(half_t)
+  {
+  }
+
+  // Constructor for a full fenced block.
+  explicit win_fenced_block(full_t)
+  {
+#if defined(__BORLANDC__)
+    LONG barrier = 0;
+    ::InterlockedExchange(&barrier, 1);
+#elif defined(ASIO_MSVC) \
+  && ((ASIO_MSVC < 1400) || !defined(MemoryBarrier))
+# if defined(_M_IX86)
+#  pragma warning(push)
+#  pragma warning(disable:4793)
+    LONG barrier;
+    __asm { xchg barrier, eax }
+#  pragma warning(pop)
+# endif // defined(_M_IX86)
+#else
+    MemoryBarrier();
+#endif
+  }
+
+  // Destructor.
+  ~win_fenced_block()
+  {
+#if defined(__BORLANDC__)
+    LONG barrier = 0;
+    ::InterlockedExchange(&barrier, 1);
+#elif defined(ASIO_MSVC) \
+  && ((ASIO_MSVC < 1400) || !defined(MemoryBarrier))
+# if defined(_M_IX86)
+#  pragma warning(push)
+#  pragma warning(disable:4793)
+    LONG barrier;
+    __asm { xchg barrier, eax }
+#  pragma warning(pop)
+# endif // defined(_M_IX86)
+#else
+    MemoryBarrier();
+#endif
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS) && !defined(UNDER_CE)
+
+#endif // ASIO_DETAIL_WIN_FENCED_BLOCK_HPP
diff --git a/subprojects/asio/include/asio/detail/win_global.hpp b/subprojects/asio/include/asio/detail/win_global.hpp
new file mode 100644
index 000000000..dd0a55564
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_global.hpp
@@ -0,0 +1,74 @@
+//
+// detail/win_global.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_GLOBAL_HPP
+#define ASIO_DETAIL_WIN_GLOBAL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/static_mutex.hpp"
+#include "asio/detail/tss_ptr.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename T>
+struct win_global_impl
+{
+  // Destructor automatically cleans up the global.
+  ~win_global_impl()
+  {
+    delete ptr_;
+  }
+
+  static win_global_impl instance_;
+  static static_mutex mutex_;
+  static T* ptr_;
+  static tss_ptr<T> tss_ptr_;
+};
+
+template <typename T>
+win_global_impl<T> win_global_impl<T>::instance_ = { 0 };
+
+template <typename T>
+static_mutex win_global_impl<T>::mutex_ = ASIO_STATIC_MUTEX_INIT;
+
+template <typename T>
+T* win_global_impl<T>::ptr_ = 0;
+
+template <typename T>
+tss_ptr<T> win_global_impl<T>::tss_ptr_;
+
+template <typename T>
+T& win_global()
+{
+  if (static_cast<T*>(win_global_impl<T>::tss_ptr_) == 0)
+  {
+    win_global_impl<T>::mutex_.init();
+    static_mutex::scoped_lock lock(win_global_impl<T>::mutex_);
+    if (win_global_impl<T>::ptr_ == 0)
+      win_global_impl<T>::ptr_ = new T;
+    win_global_impl<T>::tss_ptr_ = win_global_impl<T>::ptr_;
+  }
+
+  return *win_global_impl<T>::tss_ptr_;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WIN_GLOBAL_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_handle_read_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_handle_read_op.hpp
new file mode 100644
index 000000000..88e3f6c7b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_handle_read_op.hpp
@@ -0,0 +1,111 @@
+//
+// detail/win_iocp_handle_read_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_HANDLE_READ_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_HANDLE_READ_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/error.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence, typename Handler>
+class win_iocp_handle_read_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_handle_read_op);
+
+  win_iocp_handle_read_op(
+      const MutableBufferSequence& buffers, Handler& handler)
+    : operation(&win_iocp_handle_read_op::do_complete),
+      buffers_(buffers),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t bytes_transferred)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_handle_read_op* o(static_cast<win_iocp_handle_read_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    if (owner)
+    {
+      // Check whether buffers are still valid.
+      buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    // Map non-portable errors to their portable counterparts.
+    if (ec.value() == ERROR_HANDLE_EOF)
+      ec = asio::error::eof;
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  MutableBufferSequence buffers_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_HANDLE_READ_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_handle_service.hpp b/subprojects/asio/include/asio/detail/win_iocp_handle_service.hpp
new file mode 100644
index 000000000..849fe8f18
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_handle_service.hpp
@@ -0,0 +1,323 @@
+//
+// detail/win_iocp_handle_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_HANDLE_SERVICE_HPP
+#define ASIO_DETAIL_WIN_IOCP_HANDLE_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/cstdint.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/win_iocp_handle_read_op.hpp"
+#include "asio/detail/win_iocp_handle_write_op.hpp"
+#include "asio/detail/win_iocp_io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_iocp_handle_service :
+  public service_base<win_iocp_handle_service>
+{
+public:
+  // The native type of a stream handle.
+  typedef HANDLE native_handle_type;
+
+  // The implementation type of the stream handle.
+  class implementation_type
+  {
+  public:
+    // Default constructor.
+    implementation_type()
+      : handle_(INVALID_HANDLE_VALUE),
+        safe_cancellation_thread_id_(0),
+        next_(0),
+        prev_(0)
+    {
+    }
+
+  private:
+    // Only this service will have access to the internal values.
+    friend class win_iocp_handle_service;
+
+    // The native stream handle representation.
+    native_handle_type handle_;
+
+    // The ID of the thread from which it is safe to cancel asynchronous
+    // operations. 0 means no asynchronous operations have been started yet.
+    // ~0 means asynchronous operations have been started from more than one
+    // thread, and cancellation is not supported for the handle.
+    DWORD safe_cancellation_thread_id_;
+
+    // Pointers to adjacent handle implementations in linked list.
+    implementation_type* next_;
+    implementation_type* prev_;
+  };
+
+  ASIO_DECL win_iocp_handle_service(asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Construct a new handle implementation.
+  ASIO_DECL void construct(implementation_type& impl);
+
+  // Move-construct a new handle implementation.
+  ASIO_DECL void move_construct(implementation_type& impl,
+      implementation_type& other_impl);
+
+  // Move-assign from another handle implementation.
+  ASIO_DECL void move_assign(implementation_type& impl,
+      win_iocp_handle_service& other_service,
+      implementation_type& other_impl);
+
+  // Destroy a handle implementation.
+  ASIO_DECL void destroy(implementation_type& impl);
+
+  // Assign a native handle to a handle implementation.
+  ASIO_DECL asio::error_code assign(implementation_type& impl,
+      const native_handle_type& handle, asio::error_code& ec);
+
+  // Determine whether the handle is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return impl.handle_ != INVALID_HANDLE_VALUE;
+  }
+
+  // Destroy a handle implementation.
+  ASIO_DECL asio::error_code close(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Get the native handle representation.
+  native_handle_type native_handle(const implementation_type& impl) const
+  {
+    return impl.handle_;
+  }
+
+  // Cancel all operations associated with the handle.
+  ASIO_DECL asio::error_code cancel(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Write the given data. Returns the number of bytes written.
+  template <typename ConstBufferSequence>
+  size_t write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return write_some_at(impl, 0, buffers, ec);
+  }
+
+  // Write the given data at the specified offset. Returns the number of bytes
+  // written.
+  template <typename ConstBufferSequence>
+  size_t write_some_at(implementation_type& impl, uint64_t offset,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    asio::const_buffer buffer =
+      buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence>::first(buffers);
+
+    return do_write(impl, offset, buffer, ec);
+  }
+
+  // Start an asynchronous write. The data being written must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_handle_write_op<ConstBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(buffers, handler);
+
+    ASIO_HANDLER_CREATION((iocp_service_.context(), *p.p, "handle", &impl,
+          reinterpret_cast<uintmax_t>(impl.handle_), "async_write_some"));
+
+    start_write_op(impl, 0,
+        buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::first(buffers), p.p);
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous write at a specified offset. The data being written
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_write_some_at(implementation_type& impl, uint64_t offset,
+      const ConstBufferSequence& buffers, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_handle_write_op<ConstBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(buffers, handler);
+
+    ASIO_HANDLER_CREATION((iocp_service_.context(), *p.p, "handle", &impl,
+          reinterpret_cast<uintmax_t>(impl.handle_), "async_write_some_at"));
+
+    start_write_op(impl, offset,
+        buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::first(buffers), p.p);
+    p.v = p.p = 0;
+  }
+
+  // Read some data. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  size_t read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return read_some_at(impl, 0, buffers, ec);
+  }
+
+  // Read some data at a specified offset. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  size_t read_some_at(implementation_type& impl, uint64_t offset,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    asio::mutable_buffer buffer =
+      buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence>::first(buffers);
+
+    return do_read(impl, offset, buffer, ec);
+  }
+
+  // Start an asynchronous read. The buffer for the data being received must be
+  // valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_handle_read_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(buffers, handler);
+
+    ASIO_HANDLER_CREATION((iocp_service_.context(), *p.p, "handle", &impl,
+          reinterpret_cast<uintmax_t>(impl.handle_), "async_read_some"));
+
+    start_read_op(impl, 0,
+        buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::first(buffers), p.p);
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous read at a specified offset. The buffer for the data
+  // being received must be valid for the lifetime of the asynchronous
+  // operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_read_some_at(implementation_type& impl, uint64_t offset,
+      const MutableBufferSequence& buffers, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_handle_read_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(buffers, handler);
+
+    ASIO_HANDLER_CREATION((iocp_service_.context(), *p.p, "handle", &impl,
+          reinterpret_cast<uintmax_t>(impl.handle_), "async_read_some_at"));
+
+    start_read_op(impl, offset,
+        buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::first(buffers), p.p);
+    p.v = p.p = 0;
+  }
+
+private:
+  // Prevent the use of the null_buffers type with this service.
+  size_t write_some(implementation_type& impl,
+      const null_buffers& buffers, asio::error_code& ec);
+  size_t write_some_at(implementation_type& impl, uint64_t offset,
+      const null_buffers& buffers, asio::error_code& ec);
+  template <typename Handler>
+  void async_write_some(implementation_type& impl,
+      const null_buffers& buffers, Handler& handler);
+  template <typename Handler>
+  void async_write_some_at(implementation_type& impl, uint64_t offset,
+      const null_buffers& buffers, Handler& handler);
+  size_t read_some(implementation_type& impl,
+      const null_buffers& buffers, asio::error_code& ec);
+  size_t read_some_at(implementation_type& impl, uint64_t offset,
+      const null_buffers& buffers, asio::error_code& ec);
+  template <typename Handler>
+  void async_read_some(implementation_type& impl,
+      const null_buffers& buffers, Handler& handler);
+  template <typename Handler>
+  void async_read_some_at(implementation_type& impl, uint64_t offset,
+      const null_buffers& buffers, Handler& handler);
+
+  // Helper class for waiting for synchronous operations to complete.
+  class overlapped_wrapper;
+
+  // Helper function to perform a synchronous write operation.
+  ASIO_DECL size_t do_write(implementation_type& impl,
+      uint64_t offset, const asio::const_buffer& buffer,
+      asio::error_code& ec);
+
+  // Helper function to start a write operation.
+  ASIO_DECL void start_write_op(implementation_type& impl,
+      uint64_t offset, const asio::const_buffer& buffer,
+      operation* op);
+
+  // Helper function to perform a synchronous write operation.
+  ASIO_DECL size_t do_read(implementation_type& impl,
+      uint64_t offset, const asio::mutable_buffer& buffer,
+      asio::error_code& ec);
+
+  // Helper function to start a read operation.
+  ASIO_DECL void start_read_op(implementation_type& impl,
+      uint64_t offset, const asio::mutable_buffer& buffer,
+      operation* op);
+
+  // Update the ID of the thread from which cancellation is safe.
+  ASIO_DECL void update_cancellation_thread_id(implementation_type& impl);
+
+  // Helper function to close a handle when the associated object is being
+  // destroyed.
+  ASIO_DECL void close_for_destruction(implementation_type& impl);
+
+  // The IOCP service used for running asynchronous operations and dispatching
+  // handlers.
+  win_iocp_io_context& iocp_service_;
+
+  // Mutex to protect access to the linked list of implementations.
+  mutex mutex_;
+
+  // The head of a linked list of all implementations.
+  implementation_type* impl_list_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_iocp_handle_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_HANDLE_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_handle_write_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_handle_write_op.hpp
new file mode 100644
index 000000000..d7bb9443a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_handle_write_op.hpp
@@ -0,0 +1,103 @@
+//
+// detail/win_iocp_handle_write_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_HANDLE_WRITE_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_HANDLE_WRITE_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/error.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename ConstBufferSequence, typename Handler>
+class win_iocp_handle_write_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_handle_write_op);
+
+  win_iocp_handle_write_op(const ConstBufferSequence& buffers, Handler& handler)
+    : operation(&win_iocp_handle_write_op::do_complete),
+      buffers_(buffers),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& ec, std::size_t bytes_transferred)
+  {
+    // Take ownership of the operation object.
+    win_iocp_handle_write_op* o(static_cast<win_iocp_handle_write_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    if (owner)
+    {
+      // Check whether buffers are still valid.
+      buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  ConstBufferSequence buffers_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_HANDLE_WRITE_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_io_context.hpp b/subprojects/asio/include/asio/detail/win_iocp_io_context.hpp
new file mode 100644
index 000000000..11bf58b7d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_io_context.hpp
@@ -0,0 +1,328 @@
+//
+// detail/win_iocp_io_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_IO_CONTEXT_HPP
+#define ASIO_DETAIL_WIN_IOCP_IO_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/limits.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/thread.hpp"
+#include "asio/detail/thread_context.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+#include "asio/detail/timer_queue_set.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/detail/win_iocp_operation.hpp"
+#include "asio/detail/win_iocp_thread_info.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class wait_op;
+
+class win_iocp_io_context
+  : public execution_context_service_base<win_iocp_io_context>,
+    public thread_context
+{
+public:
+  // Constructor. Specifies a concurrency hint that is passed through to the
+  // underlying I/O completion port.
+  ASIO_DECL win_iocp_io_context(asio::execution_context& ctx,
+      int concurrency_hint = -1);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Initialise the task. Nothing to do here.
+  void init_task()
+  {
+  }
+
+  // Register a handle with the IO completion port.
+  ASIO_DECL asio::error_code register_handle(
+      HANDLE handle, asio::error_code& ec);
+
+  // Run the event loop until stopped or no more work.
+  ASIO_DECL size_t run(asio::error_code& ec);
+
+  // Run until stopped or one operation is performed.
+  ASIO_DECL size_t run_one(asio::error_code& ec);
+
+  // Run until timeout, interrupted, or one operation is performed.
+  ASIO_DECL size_t wait_one(long usec, asio::error_code& ec);
+
+  // Poll for operations without blocking.
+  ASIO_DECL size_t poll(asio::error_code& ec);
+
+  // Poll for one operation without blocking.
+  ASIO_DECL size_t poll_one(asio::error_code& ec);
+
+  // Stop the event processing loop.
+  ASIO_DECL void stop();
+
+  // Determine whether the io_context is stopped.
+  bool stopped() const
+  {
+    return ::InterlockedExchangeAdd(&stopped_, 0) != 0;
+  }
+
+  // Restart in preparation for a subsequent run invocation.
+  void restart()
+  {
+    ::InterlockedExchange(&stopped_, 0);
+  }
+
+  // Notify that some work has started.
+  void work_started()
+  {
+    ::InterlockedIncrement(&outstanding_work_);
+  }
+
+  // Notify that some work has finished.
+  void work_finished()
+  {
+    if (::InterlockedDecrement(&outstanding_work_) == 0)
+      stop();
+  }
+
+  // Return whether a handler can be dispatched immediately.
+  bool can_dispatch()
+  {
+    return thread_call_stack::contains(this) != 0;
+  }
+
+  // Request invocation of the given operation and return immediately. Assumes
+  // that work_started() has not yet been called for the operation.
+  void post_immediate_completion(win_iocp_operation* op, bool)
+  {
+    work_started();
+    post_deferred_completion(op);
+  }
+
+  // Request invocation of the given operation and return immediately. Assumes
+  // that work_started() was previously called for the operation.
+  ASIO_DECL void post_deferred_completion(win_iocp_operation* op);
+
+  // Request invocation of the given operation and return immediately. Assumes
+  // that work_started() was previously called for the operations.
+  ASIO_DECL void post_deferred_completions(
+      op_queue<win_iocp_operation>& ops);
+
+  // Request invocation of the given operation using the thread-private queue
+  // and return immediately. Assumes that work_started() has not yet been
+  // called for the operation.
+  void post_private_immediate_completion(win_iocp_operation* op)
+  {
+    post_immediate_completion(op, false);
+  }
+
+  // Request invocation of the given operation using the thread-private queue
+  // and return immediately. Assumes that work_started() was previously called
+  // for the operation.
+  void post_private_deferred_completion(win_iocp_operation* op)
+  {
+    post_deferred_completion(op);
+  }
+
+  // Enqueue the given operation following a failed attempt to dispatch the
+  // operation for immediate invocation.
+  void do_dispatch(operation* op)
+  {
+    post_immediate_completion(op, false);
+  }
+
+  // Process unfinished operations as part of a shutdown operation. Assumes
+  // that work_started() was previously called for the operations.
+  ASIO_DECL void abandon_operations(op_queue<operation>& ops);
+
+  // Called after starting an overlapped I/O operation that did not complete
+  // immediately. The caller must have already called work_started() prior to
+  // starting the operation.
+  ASIO_DECL void on_pending(win_iocp_operation* op);
+
+  // Called after starting an overlapped I/O operation that completed
+  // immediately. The caller must have already called work_started() prior to
+  // starting the operation.
+  ASIO_DECL void on_completion(win_iocp_operation* op,
+      DWORD last_error = 0, DWORD bytes_transferred = 0);
+
+  // Called after starting an overlapped I/O operation that completed
+  // immediately. The caller must have already called work_started() prior to
+  // starting the operation.
+  ASIO_DECL void on_completion(win_iocp_operation* op,
+      const asio::error_code& ec, DWORD bytes_transferred = 0);
+
+  // Add a new timer queue to the service.
+  template <typename Time_Traits>
+  void add_timer_queue(timer_queue<Time_Traits>& timer_queue);
+
+  // Remove a timer queue from the service.
+  template <typename Time_Traits>
+  void remove_timer_queue(timer_queue<Time_Traits>& timer_queue);
+
+  // Schedule a new operation in the given timer queue to expire at the
+  // specified absolute time.
+  template <typename Time_Traits>
+  void schedule_timer(timer_queue<Time_Traits>& queue,
+      const typename Time_Traits::time_type& time,
+      typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
+
+  // Cancel the timer associated with the given token. Returns the number of
+  // handlers that have been posted or dispatched.
+  template <typename Time_Traits>
+  std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& timer,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
+
+  // Move the timer operations associated with the given timer.
+  template <typename Time_Traits>
+  void move_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& to,
+      typename timer_queue<Time_Traits>::per_timer_data& from);
+
+  // Get the concurrency hint that was used to initialise the io_context.
+  int concurrency_hint() const
+  {
+    return concurrency_hint_;
+  }
+
+private:
+#if defined(WINVER) && (WINVER < 0x0500)
+  typedef DWORD dword_ptr_t;
+  typedef ULONG ulong_ptr_t;
+#else // defined(WINVER) && (WINVER < 0x0500)
+  typedef DWORD_PTR dword_ptr_t;
+  typedef ULONG_PTR ulong_ptr_t;
+#endif // defined(WINVER) && (WINVER < 0x0500)
+
+  // Dequeues at most one operation from the I/O completion port, and then
+  // executes it. Returns the number of operations that were dequeued (i.e.
+  // either 0 or 1).
+  ASIO_DECL size_t do_one(DWORD msec, asio::error_code& ec);
+
+  // Helper to calculate the GetQueuedCompletionStatus timeout.
+  ASIO_DECL static DWORD get_gqcs_timeout();
+
+  // Helper function to add a new timer queue.
+  ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
+
+  // Helper function to remove a timer queue.
+  ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
+
+  // Called to recalculate and update the timeout.
+  ASIO_DECL void update_timeout();
+
+  // Helper class to call work_finished() on block exit.
+  struct work_finished_on_block_exit;
+
+  // Helper class for managing a HANDLE.
+  struct auto_handle
+  {
+    HANDLE handle;
+    auto_handle() : handle(0) {}
+    ~auto_handle() { if (handle) ::CloseHandle(handle); }
+  };
+
+  // The IO completion port used for queueing operations.
+  auto_handle iocp_;
+
+  // The count of unfinished work.
+  long outstanding_work_;
+
+  // Flag to indicate whether the event loop has been stopped.
+  mutable long stopped_;
+
+  // Flag to indicate whether there is an in-flight stop event. Every event
+  // posted using PostQueuedCompletionStatus consumes non-paged pool, so to
+  // avoid exhausting this resouce we limit the number of outstanding events.
+  long stop_event_posted_;
+
+  // Flag to indicate whether the service has been shut down.
+  long shutdown_;
+
+  enum
+  {
+    // Timeout to use with GetQueuedCompletionStatus on older versions of
+    // Windows. Some versions of windows have a "bug" where a call to
+    // GetQueuedCompletionStatus can appear stuck even though there are events
+    // waiting on the queue. Using a timeout helps to work around the issue.
+    default_gqcs_timeout = 500,
+
+    // Maximum waitable timer timeout, in milliseconds.
+    max_timeout_msec = 5 * 60 * 1000,
+
+    // Maximum waitable timer timeout, in microseconds.
+    max_timeout_usec = max_timeout_msec * 1000,
+
+    // Completion key value used to wake up a thread to dispatch timers or
+    // completed operations.
+    wake_for_dispatch = 1,
+
+    // Completion key value to indicate that an operation has posted with the
+    // original last_error and bytes_transferred values stored in the fields of
+    // the OVERLAPPED structure.
+    overlapped_contains_result = 2
+  };
+
+  // Timeout to use with GetQueuedCompletionStatus.
+  const DWORD gqcs_timeout_;
+
+  // Function object for processing timeouts in a background thread.
+  struct timer_thread_function;
+  friend struct timer_thread_function;
+
+  // Background thread used for processing timeouts.
+  scoped_ptr<thread> timer_thread_;
+
+  // A waitable timer object used for waiting for timeouts.
+  auto_handle waitable_timer_;
+
+  // Non-zero if timers or completed operations need to be dispatched.
+  long dispatch_required_;
+
+  // Mutex for protecting access to the timer queues and completed operations.
+  mutex dispatch_mutex_;
+
+  // The timer queues.
+  timer_queue_set timer_queues_;
+
+  // The operations that are ready to dispatch.
+  op_queue<win_iocp_operation> completed_ops_;
+
+  // The concurrency hint used to initialise the io_context.
+  const int concurrency_hint_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/win_iocp_io_context.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_iocp_io_context.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_IO_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_null_buffers_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_null_buffers_op.hpp
new file mode 100644
index 000000000..db70cb28a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_null_buffers_op.hpp
@@ -0,0 +1,121 @@
+//
+// detail/win_iocp_null_buffers_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_NULL_BUFFERS_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_NULL_BUFFERS_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class win_iocp_null_buffers_op : public reactor_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_null_buffers_op);
+
+  win_iocp_null_buffers_op(socket_ops::weak_cancel_token_type cancel_token,
+      Handler& handler)
+    : reactor_op(&win_iocp_null_buffers_op::do_perform,
+        &win_iocp_null_buffers_op::do_complete),
+      cancel_token_(cancel_token),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static status do_perform(reactor_op*)
+  {
+    return done;
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t bytes_transferred)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_null_buffers_op* o(static_cast<win_iocp_null_buffers_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // The reactor may have stored a result in the operation object.
+    if (o->ec_)
+      ec = o->ec_;
+
+    // Map non-portable errors to their portable counterparts.
+    if (ec.value() == ERROR_NETNAME_DELETED)
+    {
+      if (o->cancel_token_.expired())
+        ec = asio::error::operation_aborted;
+      else
+        ec = asio::error::connection_reset;
+    }
+    else if (ec.value() == ERROR_PORT_UNREACHABLE)
+    {
+      ec = asio::error::connection_refused;
+    }
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  socket_ops::weak_cancel_token_type cancel_token_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_NULL_BUFFERS_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_operation.hpp b/subprojects/asio/include/asio/detail/win_iocp_operation.hpp
new file mode 100644
index 000000000..81d43f07f
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_operation.hpp
@@ -0,0 +1,96 @@
+//
+// detail/win_iocp_operation.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_OPERATION_HPP
+#define ASIO_DETAIL_WIN_IOCP_OPERATION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/handler_tracking.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/error_code.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_iocp_io_context;
+
+// Base class for all operations. A function pointer is used instead of virtual
+// functions to avoid the associated overhead.
+class win_iocp_operation
+  : public OVERLAPPED
+    ASIO_ALSO_INHERIT_TRACKED_HANDLER
+{
+public:
+  typedef win_iocp_operation operation_type;
+
+  void complete(void* owner, const asio::error_code& ec,
+      std::size_t bytes_transferred)
+  {
+    func_(owner, this, ec, bytes_transferred);
+  }
+
+  void destroy()
+  {
+    func_(0, this, asio::error_code(), 0);
+  }
+
+protected:
+  typedef void (*func_type)(
+      void*, win_iocp_operation*,
+      const asio::error_code&, std::size_t);
+
+  win_iocp_operation(func_type func)
+    : next_(0),
+      func_(func)
+  {
+    reset();
+  }
+
+  // Prevents deletion through this type.
+  ~win_iocp_operation()
+  {
+  }
+
+  void reset()
+  {
+    Internal = 0;
+    InternalHigh = 0;
+    Offset = 0;
+    OffsetHigh = 0;
+    hEvent = 0;
+    ready_ = 0;
+  }
+
+private:
+  friend class op_queue_access;
+  friend class win_iocp_io_context;
+  win_iocp_operation* next_;
+  func_type func_;
+  long ready_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_OPERATION_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_overlapped_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_overlapped_op.hpp
new file mode 100644
index 000000000..2b2cc319b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_overlapped_op.hpp
@@ -0,0 +1,90 @@
+//
+// detail/win_iocp_overlapped_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_OVERLAPPED_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_OVERLAPPED_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/error.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class win_iocp_overlapped_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_overlapped_op);
+
+  win_iocp_overlapped_op(Handler& handler)
+    : operation(&win_iocp_overlapped_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& ec, std::size_t bytes_transferred)
+  {
+    // Take ownership of the operation object.
+    win_iocp_overlapped_op* o(static_cast<win_iocp_overlapped_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_OVERLAPPED_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_overlapped_ptr.hpp b/subprojects/asio/include/asio/detail/win_iocp_overlapped_ptr.hpp
new file mode 100644
index 000000000..7a1911434
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_overlapped_ptr.hpp
@@ -0,0 +1,143 @@
+//
+// detail/win_iocp_overlapped_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_OVERLAPPED_PTR_HPP
+#define ASIO_DETAIL_WIN_IOCP_OVERLAPPED_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/io_context.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/win_iocp_overlapped_op.hpp"
+#include "asio/detail/win_iocp_io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Wraps a handler to create an OVERLAPPED object for use with overlapped I/O.
+class win_iocp_overlapped_ptr
+  : private noncopyable
+{
+public:
+  // Construct an empty win_iocp_overlapped_ptr.
+  win_iocp_overlapped_ptr()
+    : ptr_(0),
+      iocp_service_(0)
+  {
+  }
+
+  // Construct an win_iocp_overlapped_ptr to contain the specified handler.
+  template <typename Handler>
+  explicit win_iocp_overlapped_ptr(
+      asio::io_context& io_context, ASIO_MOVE_ARG(Handler) handler)
+    : ptr_(0),
+      iocp_service_(0)
+  {
+    this->reset(io_context, ASIO_MOVE_CAST(Handler)(handler));
+  }
+
+  // Destructor automatically frees the OVERLAPPED object unless released.
+  ~win_iocp_overlapped_ptr()
+  {
+    reset();
+  }
+
+  // Reset to empty.
+  void reset()
+  {
+    if (ptr_)
+    {
+      ptr_->destroy();
+      ptr_ = 0;
+      iocp_service_->work_finished();
+      iocp_service_ = 0;
+    }
+  }
+
+  // Reset to contain the specified handler, freeing any current OVERLAPPED
+  // object.
+  template <typename Handler>
+  void reset(asio::io_context& io_context, Handler handler)
+  {
+    typedef win_iocp_overlapped_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((io_context, *p.p,
+          "io_context", &io_context.impl_, 0, "overlapped"));
+
+    io_context.impl_.work_started();
+    reset();
+    ptr_ = p.p;
+    p.v = p.p = 0;
+    iocp_service_ = &io_context.impl_;
+  }
+
+  // Get the contained OVERLAPPED object.
+  OVERLAPPED* get()
+  {
+    return ptr_;
+  }
+
+  // Get the contained OVERLAPPED object.
+  const OVERLAPPED* get() const
+  {
+    return ptr_;
+  }
+
+  // Release ownership of the OVERLAPPED object.
+  OVERLAPPED* release()
+  {
+    if (ptr_)
+      iocp_service_->on_pending(ptr_);
+
+    OVERLAPPED* tmp = ptr_;
+    ptr_ = 0;
+    iocp_service_ = 0;
+    return tmp;
+  }
+
+  // Post completion notification for overlapped operation. Releases ownership.
+  void complete(const asio::error_code& ec,
+      std::size_t bytes_transferred)
+  {
+    if (ptr_)
+    {
+      iocp_service_->on_completion(ptr_, ec,
+          static_cast<DWORD>(bytes_transferred));
+      ptr_ = 0;
+      iocp_service_ = 0;
+    }
+  }
+
+private:
+  win_iocp_operation* ptr_;
+  win_iocp_io_context* iocp_service_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_OVERLAPPED_PTR_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_serial_port_service.hpp b/subprojects/asio/include/asio/detail/win_iocp_serial_port_service.hpp
new file mode 100644
index 000000000..ac06348ec
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_serial_port_service.hpp
@@ -0,0 +1,230 @@
+//
+// detail/win_iocp_serial_port_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SERIAL_PORT_SERVICE_HPP
+#define ASIO_DETAIL_WIN_IOCP_SERIAL_PORT_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP) && defined(ASIO_HAS_SERIAL_PORT)
+
+#include <string>
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/win_iocp_handle_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Extend win_iocp_handle_service to provide serial port support.
+class win_iocp_serial_port_service :
+  public service_base<win_iocp_serial_port_service>
+{
+public:
+  // The native type of a serial port.
+  typedef win_iocp_handle_service::native_handle_type native_handle_type;
+
+  // The implementation type of the serial port.
+  typedef win_iocp_handle_service::implementation_type implementation_type;
+
+  // Constructor.
+  ASIO_DECL win_iocp_serial_port_service(
+      asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Construct a new serial port implementation.
+  void construct(implementation_type& impl)
+  {
+    handle_service_.construct(impl);
+  }
+
+  // Move-construct a new serial port implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    handle_service_.move_construct(impl, other_impl);
+  }
+
+  // Move-assign from another serial port implementation.
+  void move_assign(implementation_type& impl,
+      win_iocp_serial_port_service& other_service,
+      implementation_type& other_impl)
+  {
+    handle_service_.move_assign(impl,
+        other_service.handle_service_, other_impl);
+  }
+
+  // Destroy a serial port implementation.
+  void destroy(implementation_type& impl)
+  {
+    handle_service_.destroy(impl);
+  }
+
+  // Open the serial port using the specified device name.
+  ASIO_DECL asio::error_code open(implementation_type& impl,
+      const std::string& device, asio::error_code& ec);
+
+  // Assign a native handle to a serial port implementation.
+  asio::error_code assign(implementation_type& impl,
+      const native_handle_type& handle, asio::error_code& ec)
+  {
+    return handle_service_.assign(impl, handle, ec);
+  }
+
+  // Determine whether the serial port is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return handle_service_.is_open(impl);
+  }
+
+  // Destroy a serial port implementation.
+  asio::error_code close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return handle_service_.close(impl, ec);
+  }
+
+  // Get the native serial port representation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return handle_service_.native_handle(impl);
+  }
+
+  // Cancel all operations associated with the handle.
+  asio::error_code cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return handle_service_.cancel(impl, ec);
+  }
+
+  // Set an option on the serial port.
+  template <typename SettableSerialPortOption>
+  asio::error_code set_option(implementation_type& impl,
+      const SettableSerialPortOption& option, asio::error_code& ec)
+  {
+    return do_set_option(impl,
+        &win_iocp_serial_port_service::store_option<SettableSerialPortOption>,
+        &option, ec);
+  }
+
+  // Get an option from the serial port.
+  template <typename GettableSerialPortOption>
+  asio::error_code get_option(const implementation_type& impl,
+      GettableSerialPortOption& option, asio::error_code& ec) const
+  {
+    return do_get_option(impl,
+        &win_iocp_serial_port_service::load_option<GettableSerialPortOption>,
+        &option, ec);
+  }
+
+  // Send a break sequence to the serial port.
+  asio::error_code send_break(implementation_type&,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Write the given data. Returns the number of bytes sent.
+  template <typename ConstBufferSequence>
+  size_t write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return handle_service_.write_some(impl, buffers, ec);
+  }
+
+  // Start an asynchronous write. The data being written must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, Handler& handler)
+  {
+    handle_service_.async_write_some(impl, buffers, handler);
+  }
+
+  // Read some data. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  size_t read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return handle_service_.read_some(impl, buffers, ec);
+  }
+
+  // Start an asynchronous read. The buffer for the data being received must be
+  // valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, Handler& handler)
+  {
+    handle_service_.async_read_some(impl, buffers, handler);
+  }
+
+private:
+  // Function pointer type for storing a serial port option.
+  typedef asio::error_code (*store_function_type)(
+      const void*, ::DCB&, asio::error_code&);
+
+  // Helper function template to store a serial port option.
+  template <typename SettableSerialPortOption>
+  static asio::error_code store_option(const void* option,
+      ::DCB& storage, asio::error_code& ec)
+  {
+    static_cast<const SettableSerialPortOption*>(option)->store(storage, ec);
+    return ec;
+  }
+
+  // Helper function to set a serial port option.
+  ASIO_DECL asio::error_code do_set_option(
+      implementation_type& impl, store_function_type store,
+      const void* option, asio::error_code& ec);
+
+  // Function pointer type for loading a serial port option.
+  typedef asio::error_code (*load_function_type)(
+      void*, const ::DCB&, asio::error_code&);
+
+  // Helper function template to load a serial port option.
+  template <typename GettableSerialPortOption>
+  static asio::error_code load_option(void* option,
+      const ::DCB& storage, asio::error_code& ec)
+  {
+    static_cast<GettableSerialPortOption*>(option)->load(storage, ec);
+    return ec;
+  }
+
+  // Helper function to get a serial port option.
+  ASIO_DECL asio::error_code do_get_option(
+      const implementation_type& impl, load_function_type load,
+      void* option, asio::error_code& ec) const;
+
+  // The implementation used for initiating asynchronous operations.
+  win_iocp_handle_service handle_service_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_iocp_serial_port_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_IOCP) && defined(ASIO_HAS_SERIAL_PORT)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SERIAL_PORT_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_accept_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_accept_op.hpp
new file mode 100644
index 000000000..18e73356c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_accept_op.hpp
@@ -0,0 +1,297 @@
+//
+// detail/win_iocp_socket_accept_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_ACCEPT_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_ACCEPT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/win_iocp_socket_service_base.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Socket, typename Protocol, typename Handler>
+class win_iocp_socket_accept_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_socket_accept_op);
+
+  win_iocp_socket_accept_op(win_iocp_socket_service_base& socket_service,
+      socket_type socket, Socket& peer, const Protocol& protocol,
+      typename Protocol::endpoint* peer_endpoint,
+      bool enable_connection_aborted, Handler& handler)
+    : operation(&win_iocp_socket_accept_op::do_complete),
+      socket_service_(socket_service),
+      socket_(socket),
+      peer_(peer),
+      protocol_(protocol),
+      peer_endpoint_(peer_endpoint),
+      enable_connection_aborted_(enable_connection_aborted),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  socket_holder& new_socket()
+  {
+    return new_socket_;
+  }
+
+  void* output_buffer()
+  {
+    return output_buffer_;
+  }
+
+  DWORD address_length()
+  {
+    return sizeof(sockaddr_storage_type) + 16;
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t /*bytes_transferred*/)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_socket_accept_op* o(static_cast<win_iocp_socket_accept_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    if (owner)
+    {
+      typename Protocol::endpoint peer_endpoint;
+      std::size_t addr_len = peer_endpoint.capacity();
+      socket_ops::complete_iocp_accept(o->socket_,
+          o->output_buffer(), o->address_length(),
+          peer_endpoint.data(), &addr_len,
+          o->new_socket_.get(), ec);
+
+      // Restart the accept operation if we got the connection_aborted error
+      // and the enable_connection_aborted socket option is not set.
+      if (ec == asio::error::connection_aborted
+          && !o->enable_connection_aborted_)
+      {
+        o->reset();
+        o->socket_service_.restart_accept_op(o->socket_,
+            o->new_socket_, o->protocol_.family(),
+            o->protocol_.type(), o->protocol_.protocol(),
+            o->output_buffer(), o->address_length(), o);
+        p.v = p.p = 0;
+        return;
+      }
+
+      // If the socket was successfully accepted, transfer ownership of the
+      // socket to the peer object.
+      if (!ec)
+      {
+        o->peer_.assign(o->protocol_,
+            typename Socket::native_handle_type(
+              o->new_socket_.get(), peer_endpoint), ec);
+        if (!ec)
+          o->new_socket_.release();
+      }
+
+      // Pass endpoint back to caller.
+      if (o->peer_endpoint_)
+        *o->peer_endpoint_ = peer_endpoint;
+    }
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(o->handler_, ec);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  win_iocp_socket_service_base& socket_service_;
+  socket_type socket_;
+  socket_holder new_socket_;
+  Socket& peer_;
+  Protocol protocol_;
+  typename Protocol::endpoint* peer_endpoint_;
+  unsigned char output_buffer_[(sizeof(sockaddr_storage_type) + 16) * 2];
+  bool enable_connection_aborted_;
+  Handler handler_;
+};
+
+#if defined(ASIO_HAS_MOVE)
+
+template <typename Protocol, typename Handler>
+class win_iocp_socket_move_accept_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_socket_move_accept_op);
+
+  win_iocp_socket_move_accept_op(
+      win_iocp_socket_service_base& socket_service, socket_type socket,
+      const Protocol& protocol, asio::io_context& peer_io_context,
+      typename Protocol::endpoint* peer_endpoint,
+      bool enable_connection_aborted, Handler& handler)
+    : operation(&win_iocp_socket_move_accept_op::do_complete),
+      socket_service_(socket_service),
+      socket_(socket),
+      peer_(peer_io_context),
+      protocol_(protocol),
+      peer_endpoint_(peer_endpoint),
+      enable_connection_aborted_(enable_connection_aborted),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  socket_holder& new_socket()
+  {
+    return new_socket_;
+  }
+
+  void* output_buffer()
+  {
+    return output_buffer_;
+  }
+
+  DWORD address_length()
+  {
+    return sizeof(sockaddr_storage_type) + 16;
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t /*bytes_transferred*/)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_socket_move_accept_op* o(
+        static_cast<win_iocp_socket_move_accept_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    if (owner)
+    {
+      typename Protocol::endpoint peer_endpoint;
+      std::size_t addr_len = peer_endpoint.capacity();
+      socket_ops::complete_iocp_accept(o->socket_,
+          o->output_buffer(), o->address_length(),
+          peer_endpoint.data(), &addr_len,
+          o->new_socket_.get(), ec);
+
+      // Restart the accept operation if we got the connection_aborted error
+      // and the enable_connection_aborted socket option is not set.
+      if (ec == asio::error::connection_aborted
+          && !o->enable_connection_aborted_)
+      {
+        o->reset();
+        o->socket_service_.restart_accept_op(o->socket_,
+            o->new_socket_, o->protocol_.family(),
+            o->protocol_.type(), o->protocol_.protocol(),
+            o->output_buffer(), o->address_length(), o);
+        p.v = p.p = 0;
+        return;
+      }
+
+      // If the socket was successfully accepted, transfer ownership of the
+      // socket to the peer object.
+      if (!ec)
+      {
+        o->peer_.assign(o->protocol_,
+            typename Protocol::socket::native_handle_type(
+              o->new_socket_.get(), peer_endpoint), ec);
+        if (!ec)
+          o->new_socket_.release();
+      }
+
+      // Pass endpoint back to caller.
+      if (o->peer_endpoint_)
+        *o->peer_endpoint_ = peer_endpoint;
+    }
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::move_binder2<Handler,
+      asio::error_code, typename Protocol::socket>
+        handler(0, ASIO_MOVE_CAST(Handler)(o->handler_), ec,
+          ASIO_MOVE_CAST(typename Protocol::socket)(o->peer_));
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  win_iocp_socket_service_base& socket_service_;
+  socket_type socket_;
+  socket_holder new_socket_;
+  typename Protocol::socket peer_;
+  Protocol protocol_;
+  typename Protocol::endpoint* peer_endpoint_;
+  unsigned char output_buffer_[(sizeof(sockaddr_storage_type) + 16) * 2];
+  bool enable_connection_aborted_;
+  Handler handler_;
+};
+
+#endif // defined(ASIO_HAS_MOVE)
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_ACCEPT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_connect_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_connect_op.hpp
new file mode 100644
index 000000000..e0c52dc97
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_connect_op.hpp
@@ -0,0 +1,127 @@
+//
+// detail/win_iocp_socket_connect_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_CONNECT_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_CONNECT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_iocp_socket_connect_op_base : public reactor_op
+{
+public:
+  win_iocp_socket_connect_op_base(socket_type socket, func_type complete_func)
+    : reactor_op(&win_iocp_socket_connect_op_base::do_perform, complete_func),
+      socket_(socket),
+      connect_ex_(false)
+  {
+  }
+
+  static status do_perform(reactor_op* base)
+  {
+    win_iocp_socket_connect_op_base* o(
+        static_cast<win_iocp_socket_connect_op_base*>(base));
+
+    return socket_ops::non_blocking_connect(
+        o->socket_, o->ec_) ? done : not_done;
+  }
+
+  socket_type socket_;
+  bool connect_ex_;
+};
+
+template <typename Handler>
+class win_iocp_socket_connect_op : public win_iocp_socket_connect_op_base
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_socket_connect_op);
+
+  win_iocp_socket_connect_op(socket_type socket, Handler& handler)
+    : win_iocp_socket_connect_op_base(socket,
+        &win_iocp_socket_connect_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t /*bytes_transferred*/)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_socket_connect_op* o(
+        static_cast<win_iocp_socket_connect_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    if (owner)
+    {
+      if (o->connect_ex_)
+        socket_ops::complete_iocp_connect(o->socket_, ec);
+      else
+        ec = o->ec_;
+    }
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(o->handler_, ec);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_CONNECT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_recv_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_recv_op.hpp
new file mode 100644
index 000000000..41595405d
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_recv_op.hpp
@@ -0,0 +1,117 @@
+//
+// detail/win_iocp_socket_recv_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_RECV_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_RECV_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence, typename Handler>
+class win_iocp_socket_recv_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_socket_recv_op);
+
+  win_iocp_socket_recv_op(socket_ops::state_type state,
+      socket_ops::weak_cancel_token_type cancel_token,
+      const MutableBufferSequence& buffers, Handler& handler)
+    : operation(&win_iocp_socket_recv_op::do_complete),
+      state_(state),
+      cancel_token_(cancel_token),
+      buffers_(buffers),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t bytes_transferred)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_socket_recv_op* o(static_cast<win_iocp_socket_recv_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    // Check whether buffers are still valid.
+    if (owner)
+    {
+      buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    socket_ops::complete_iocp_recv(o->state_, o->cancel_token_,
+        buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::all_empty(o->buffers_),
+        ec, bytes_transferred);
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  socket_ops::state_type state_;
+  socket_ops::weak_cancel_token_type cancel_token_;
+  MutableBufferSequence buffers_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_RECV_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_recvfrom_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_recvfrom_op.hpp
new file mode 100644
index 000000000..843ce5bba
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_recvfrom_op.hpp
@@ -0,0 +1,125 @@
+//
+// detail/win_iocp_socket_recvfrom_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_RECVFROM_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_RECVFROM_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence, typename Endpoint, typename Handler>
+class win_iocp_socket_recvfrom_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_socket_recvfrom_op);
+
+  win_iocp_socket_recvfrom_op(Endpoint& endpoint,
+      socket_ops::weak_cancel_token_type cancel_token,
+      const MutableBufferSequence& buffers, Handler& handler)
+    : operation(&win_iocp_socket_recvfrom_op::do_complete),
+      endpoint_(endpoint),
+      endpoint_size_(static_cast<int>(endpoint.capacity())),
+      cancel_token_(cancel_token),
+      buffers_(buffers),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  int& endpoint_size()
+  {
+    return endpoint_size_;
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t bytes_transferred)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_socket_recvfrom_op* o(
+        static_cast<win_iocp_socket_recvfrom_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    // Check whether buffers are still valid.
+    if (owner)
+    {
+      buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    socket_ops::complete_iocp_recvfrom(o->cancel_token_, ec);
+
+    // Record the size of the endpoint returned by the operation.
+    o->endpoint_.resize(o->endpoint_size_);
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Endpoint& endpoint_;
+  int endpoint_size_;
+  socket_ops::weak_cancel_token_type cancel_token_;
+  MutableBufferSequence buffers_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_RECVFROM_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_recvmsg_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_recvmsg_op.hpp
new file mode 100644
index 000000000..78f36b7f3
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_recvmsg_op.hpp
@@ -0,0 +1,118 @@
+//
+// detail/win_iocp_socket_recvmsg_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_RECVMSG_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_RECVMSG_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+#include "asio/socket_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence, typename Handler>
+class win_iocp_socket_recvmsg_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_socket_recvmsg_op);
+
+  win_iocp_socket_recvmsg_op(
+      socket_ops::weak_cancel_token_type cancel_token,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags& out_flags, Handler& handler)
+    : operation(&win_iocp_socket_recvmsg_op::do_complete),
+      cancel_token_(cancel_token),
+      buffers_(buffers),
+      out_flags_(out_flags),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t bytes_transferred)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_socket_recvmsg_op* o(
+        static_cast<win_iocp_socket_recvmsg_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    // Check whether buffers are still valid.
+    if (owner)
+    {
+      buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    socket_ops::complete_iocp_recvmsg(o->cancel_token_, ec);
+    o->out_flags_ = 0;
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  socket_ops::weak_cancel_token_type cancel_token_;
+  MutableBufferSequence buffers_;
+  socket_base::message_flags& out_flags_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_RECVMSG_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_send_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_send_op.hpp
new file mode 100644
index 000000000..e1c7ab93c
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_send_op.hpp
@@ -0,0 +1,111 @@
+//
+// detail/win_iocp_socket_send_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_SEND_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_SEND_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename ConstBufferSequence, typename Handler>
+class win_iocp_socket_send_op : public operation
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_socket_send_op);
+
+  win_iocp_socket_send_op(socket_ops::weak_cancel_token_type cancel_token,
+      const ConstBufferSequence& buffers, Handler& handler)
+    : operation(&win_iocp_socket_send_op::do_complete),
+      cancel_token_(cancel_token),
+      buffers_(buffers),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t bytes_transferred)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_socket_send_op* o(static_cast<win_iocp_socket_send_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    // Check whether buffers are still valid.
+    if (owner)
+    {
+      buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    socket_ops::complete_iocp_send(o->cancel_token_, ec);
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, ec, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  socket_ops::weak_cancel_token_type cancel_token_;
+  ConstBufferSequence buffers_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_SEND_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_service.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_service.hpp
new file mode 100644
index 000000000..3f01b4d3e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_service.hpp
@@ -0,0 +1,599 @@
+//
+// detail/win_iocp_socket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include <cstring>
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/socket_base.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/select_reactor.hpp"
+#include "asio/detail/socket_holder.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/win_iocp_io_context.hpp"
+#include "asio/detail/win_iocp_null_buffers_op.hpp"
+#include "asio/detail/win_iocp_socket_accept_op.hpp"
+#include "asio/detail/win_iocp_socket_connect_op.hpp"
+#include "asio/detail/win_iocp_socket_recvfrom_op.hpp"
+#include "asio/detail/win_iocp_socket_send_op.hpp"
+#include "asio/detail/win_iocp_socket_service_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol>
+class win_iocp_socket_service :
+  public service_base<win_iocp_socket_service<Protocol> >,
+  public win_iocp_socket_service_base
+{
+public:
+  // The protocol type.
+  typedef Protocol protocol_type;
+
+  // The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  // The native type of a socket.
+  class native_handle_type
+  {
+  public:
+    native_handle_type(socket_type s)
+      : socket_(s),
+        have_remote_endpoint_(false)
+    {
+    }
+
+    native_handle_type(socket_type s, const endpoint_type& ep)
+      : socket_(s),
+        have_remote_endpoint_(true),
+        remote_endpoint_(ep)
+    {
+    }
+
+    void operator=(socket_type s)
+    {
+      socket_ = s;
+      have_remote_endpoint_ = false;
+      remote_endpoint_ = endpoint_type();
+    }
+
+    operator socket_type() const
+    {
+      return socket_;
+    }
+
+    bool have_remote_endpoint() const
+    {
+      return have_remote_endpoint_;
+    }
+
+    endpoint_type remote_endpoint() const
+    {
+      return remote_endpoint_;
+    }
+
+  private:
+    socket_type socket_;
+    bool have_remote_endpoint_;
+    endpoint_type remote_endpoint_;
+  };
+
+  // The implementation type of the socket.
+  struct implementation_type :
+    win_iocp_socket_service_base::base_implementation_type
+  {
+    // Default constructor.
+    implementation_type()
+      : protocol_(endpoint_type().protocol()),
+        have_remote_endpoint_(false),
+        remote_endpoint_()
+    {
+    }
+
+    // The protocol associated with the socket.
+    protocol_type protocol_;
+
+    // Whether we have a cached remote endpoint.
+    bool have_remote_endpoint_;
+
+    // A cached remote endpoint.
+    endpoint_type remote_endpoint_;
+  };
+
+  // Constructor.
+  win_iocp_socket_service(asio::io_context& io_context)
+    : service_base<win_iocp_socket_service<Protocol> >(io_context),
+      win_iocp_socket_service_base(io_context)
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    this->base_shutdown();
+  }
+
+  // Move-construct a new socket implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    this->base_move_construct(impl, other_impl);
+
+    impl.protocol_ = other_impl.protocol_;
+    other_impl.protocol_ = endpoint_type().protocol();
+
+    impl.have_remote_endpoint_ = other_impl.have_remote_endpoint_;
+    other_impl.have_remote_endpoint_ = false;
+
+    impl.remote_endpoint_ = other_impl.remote_endpoint_;
+    other_impl.remote_endpoint_ = endpoint_type();
+  }
+
+  // Move-assign from another socket implementation.
+  void move_assign(implementation_type& impl,
+      win_iocp_socket_service_base& other_service,
+      implementation_type& other_impl)
+  {
+    this->base_move_assign(impl, other_service, other_impl);
+
+    impl.protocol_ = other_impl.protocol_;
+    other_impl.protocol_ = endpoint_type().protocol();
+
+    impl.have_remote_endpoint_ = other_impl.have_remote_endpoint_;
+    other_impl.have_remote_endpoint_ = false;
+
+    impl.remote_endpoint_ = other_impl.remote_endpoint_;
+    other_impl.remote_endpoint_ = endpoint_type();
+  }
+
+  // Move-construct a new socket implementation from another protocol type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      win_iocp_socket_service<Protocol1>&,
+      typename win_iocp_socket_service<
+        Protocol1>::implementation_type& other_impl)
+  {
+    this->base_move_construct(impl, other_impl);
+
+    impl.protocol_ = protocol_type(other_impl.protocol_);
+    other_impl.protocol_ = typename Protocol1::endpoint().protocol();
+
+    impl.have_remote_endpoint_ = other_impl.have_remote_endpoint_;
+    other_impl.have_remote_endpoint_ = false;
+
+    impl.remote_endpoint_ = other_impl.remote_endpoint_;
+    other_impl.remote_endpoint_ = typename Protocol1::endpoint();
+  }
+
+  // Open a new socket implementation.
+  asio::error_code open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    if (!do_open(impl, protocol.family(),
+          protocol.type(), protocol.protocol(), ec))
+    {
+      impl.protocol_ = protocol;
+      impl.have_remote_endpoint_ = false;
+      impl.remote_endpoint_ = endpoint_type();
+    }
+    return ec;
+  }
+
+  // Assign a native socket to a socket implementation.
+  asio::error_code assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_socket,
+      asio::error_code& ec)
+  {
+    if (!do_assign(impl, protocol.type(), native_socket, ec))
+    {
+      impl.protocol_ = protocol;
+      impl.have_remote_endpoint_ = native_socket.have_remote_endpoint();
+      impl.remote_endpoint_ = native_socket.remote_endpoint();
+    }
+    return ec;
+  }
+
+  // Get the native socket representation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    if (impl.have_remote_endpoint_)
+      return native_handle_type(impl.socket_, impl.remote_endpoint_);
+    return native_handle_type(impl.socket_);
+  }
+
+  // Bind the socket to the specified local endpoint.
+  asio::error_code bind(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    socket_ops::bind(impl.socket_, endpoint.data(), endpoint.size(), ec);
+    return ec;
+  }
+
+  // Set a socket option.
+  template <typename Option>
+  asio::error_code set_option(implementation_type& impl,
+      const Option& option, asio::error_code& ec)
+  {
+    socket_ops::setsockopt(impl.socket_, impl.state_,
+        option.level(impl.protocol_), option.name(impl.protocol_),
+        option.data(impl.protocol_), option.size(impl.protocol_), ec);
+    return ec;
+  }
+
+  // Set a socket option.
+  template <typename Option>
+  asio::error_code get_option(const implementation_type& impl,
+      Option& option, asio::error_code& ec) const
+  {
+    std::size_t size = option.size(impl.protocol_);
+    socket_ops::getsockopt(impl.socket_, impl.state_,
+        option.level(impl.protocol_), option.name(impl.protocol_),
+        option.data(impl.protocol_), &size, ec);
+    if (!ec)
+      option.resize(impl.protocol_, size);
+    return ec;
+  }
+
+  // Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    endpoint_type endpoint;
+    std::size_t addr_len = endpoint.capacity();
+    if (socket_ops::getsockname(impl.socket_, endpoint.data(), &addr_len, ec))
+      return endpoint_type();
+    endpoint.resize(addr_len);
+    return endpoint;
+  }
+
+  // Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    endpoint_type endpoint = impl.remote_endpoint_;
+    std::size_t addr_len = endpoint.capacity();
+    if (socket_ops::getpeername(impl.socket_, endpoint.data(),
+          &addr_len, impl.have_remote_endpoint_, ec))
+      return endpoint_type();
+    endpoint.resize(addr_len);
+    return endpoint;
+  }
+
+  // Disable sends or receives on the socket.
+  asio::error_code shutdown(base_implementation_type& impl,
+      socket_base::shutdown_type what, asio::error_code& ec)
+  {
+    socket_ops::shutdown(impl.socket_, what, ec);
+    return ec;
+  }
+
+  // Send a datagram to the specified endpoint. Returns the number of bytes
+  // sent.
+  template <typename ConstBufferSequence>
+  size_t send_to(implementation_type& impl, const ConstBufferSequence& buffers,
+      const endpoint_type& destination, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_sendto(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), flags,
+        destination.data(), destination.size(), ec);
+  }
+
+  // Wait until data can be sent without blocking.
+  size_t send_to(implementation_type& impl, const null_buffers&,
+      const endpoint_type&, socket_base::message_flags,
+      asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous send. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_send_to(implementation_type& impl,
+      const ConstBufferSequence& buffers, const endpoint_type& destination,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_send_op<ConstBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, buffers, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_send_to"));
+
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(buffers);
+
+    start_send_to_op(impl, bufs.buffers(), bufs.count(),
+        destination.data(), static_cast<int>(destination.size()),
+        flags, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous wait until data can be sent without blocking.
+  template <typename Handler>
+  void async_send_to(implementation_type& impl, const null_buffers&,
+      const endpoint_type&, socket_base::message_flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_send_to(null_buffers)"));
+
+    start_reactor_op(impl, select_reactor::write_op, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Receive a datagram with the endpoint of the sender. Returns the number of
+  // bytes received.
+  template <typename MutableBufferSequence>
+  size_t receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      endpoint_type& sender_endpoint, socket_base::message_flags flags,
+      asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    std::size_t addr_len = sender_endpoint.capacity();
+    std::size_t bytes_recvd = socket_ops::sync_recvfrom(
+        impl.socket_, impl.state_, bufs.buffers(), bufs.count(),
+        flags, sender_endpoint.data(), &addr_len, ec);
+
+    if (!ec)
+      sender_endpoint.resize(addr_len);
+
+    return bytes_recvd;
+  }
+
+  // Wait until data can be received without blocking.
+  size_t receive_from(implementation_type& impl,
+      const null_buffers&, endpoint_type& sender_endpoint,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+
+    // Reset endpoint since it can be given no sensible value at this time.
+    sender_endpoint = endpoint_type();
+
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received and
+  // the sender_endpoint object must both be valid for the lifetime of the
+  // asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers, endpoint_type& sender_endp,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_recvfrom_op<
+      MutableBufferSequence, endpoint_type, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(sender_endp, impl.cancel_token_, buffers, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_receive_from"));
+
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    start_receive_from_op(impl, bufs.buffers(), bufs.count(),
+        sender_endp.data(), flags, &p.p->endpoint_size(), p.p);
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive_from(implementation_type& impl,
+      const null_buffers&, endpoint_type& sender_endpoint,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_receive_from(null_buffers)"));
+
+    // Reset endpoint since it can be given no sensible value at this time.
+    sender_endpoint = endpoint_type();
+
+    start_null_buffers_receive_op(impl, flags, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Accept a new connection.
+  template <typename Socket>
+  asio::error_code accept(implementation_type& impl, Socket& peer,
+      endpoint_type* peer_endpoint, asio::error_code& ec)
+  {
+    // We cannot accept a socket that is already open.
+    if (peer.is_open())
+    {
+      ec = asio::error::already_open;
+      return ec;
+    }
+
+    std::size_t addr_len = peer_endpoint ? peer_endpoint->capacity() : 0;
+    socket_holder new_socket(socket_ops::sync_accept(impl.socket_,
+          impl.state_, peer_endpoint ? peer_endpoint->data() : 0,
+          peer_endpoint ? &addr_len : 0, ec));
+
+    // On success, assign new connection to peer socket object.
+    if (new_socket.get() != invalid_socket)
+    {
+      if (peer_endpoint)
+        peer_endpoint->resize(addr_len);
+      peer.assign(impl.protocol_, new_socket.get(), ec);
+      if (!ec)
+        new_socket.release();
+    }
+
+    return ec;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  // Accept a new connection.
+  typename Protocol::socket accept(implementation_type& impl,
+      io_context* peer_io_context, endpoint_type* peer_endpoint,
+      asio::error_code& ec)
+  {
+    typename Protocol::socket peer(
+        peer_io_context ? *peer_io_context : io_context_);
+
+    std::size_t addr_len = peer_endpoint ? peer_endpoint->capacity() : 0;
+    socket_holder new_socket(socket_ops::sync_accept(impl.socket_,
+          impl.state_, peer_endpoint ? peer_endpoint->data() : 0,
+          peer_endpoint ? &addr_len : 0, ec));
+
+    // On success, assign new connection to peer socket object.
+    if (new_socket.get() != invalid_socket)
+    {
+      if (peer_endpoint)
+        peer_endpoint->resize(addr_len);
+      peer.assign(impl.protocol_, new_socket.get(), ec);
+      if (!ec)
+        new_socket.release();
+    }
+
+    return peer;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  // Start an asynchronous accept. The peer and peer_endpoint objects
+  // must be valid until the accept's handler is invoked.
+  template <typename Socket, typename Handler>
+  void async_accept(implementation_type& impl, Socket& peer,
+      endpoint_type* peer_endpoint, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_accept_op<Socket, protocol_type, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    bool enable_connection_aborted =
+      (impl.state_ & socket_ops::enable_connection_aborted) != 0;
+    p.p = new (p.v) op(*this, impl.socket_, peer, impl.protocol_,
+        peer_endpoint, enable_connection_aborted, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_accept"));
+
+    start_accept_op(impl, peer.is_open(), p.p->new_socket(),
+        impl.protocol_.family(), impl.protocol_.type(),
+        impl.protocol_.protocol(), p.p->output_buffer(),
+        p.p->address_length(), p.p);
+    p.v = p.p = 0;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  // Start an asynchronous accept. The peer and peer_endpoint objects
+  // must be valid until the accept's handler is invoked.
+  template <typename Handler>
+  void async_accept(implementation_type& impl,
+      asio::io_context* peer_io_context,
+      endpoint_type* peer_endpoint, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_move_accept_op<protocol_type, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    bool enable_connection_aborted =
+      (impl.state_ & socket_ops::enable_connection_aborted) != 0;
+    p.p = new (p.v) op(*this, impl.socket_, impl.protocol_,
+        peer_io_context ? *peer_io_context : io_context_,
+        peer_endpoint, enable_connection_aborted, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_accept"));
+
+    start_accept_op(impl, false, p.p->new_socket(),
+        impl.protocol_.family(), impl.protocol_.type(),
+        impl.protocol_.protocol(), p.p->output_buffer(),
+        p.p->address_length(), p.p);
+    p.v = p.p = 0;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  // Connect the socket to the specified endpoint.
+  asio::error_code connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    socket_ops::sync_connect(impl.socket_,
+        peer_endpoint.data(), peer_endpoint.size(), ec);
+    return ec;
+  }
+
+  // Start an asynchronous connect.
+  template <typename Handler>
+  void async_connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_connect_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.socket_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_connect"));
+
+    start_connect_op(impl, impl.protocol_.family(), impl.protocol_.type(),
+        peer_endpoint.data(), static_cast<int>(peer_endpoint.size()), p.p);
+    p.v = p.p = 0;
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_socket_service_base.hpp b/subprojects/asio/include/asio/detail/win_iocp_socket_service_base.hpp
new file mode 100644
index 000000000..ef1d7180e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_socket_service_base.hpp
@@ -0,0 +1,591 @@
+//
+// detail/win_iocp_socket_service_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_BASE_HPP
+#define ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/socket_base.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/operation.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/select_reactor.hpp"
+#include "asio/detail/socket_holder.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/win_iocp_io_context.hpp"
+#include "asio/detail/win_iocp_null_buffers_op.hpp"
+#include "asio/detail/win_iocp_socket_connect_op.hpp"
+#include "asio/detail/win_iocp_socket_send_op.hpp"
+#include "asio/detail/win_iocp_socket_recv_op.hpp"
+#include "asio/detail/win_iocp_socket_recvmsg_op.hpp"
+#include "asio/detail/win_iocp_wait_op.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_iocp_socket_service_base
+{
+public:
+  // The implementation type of the socket.
+  struct base_implementation_type
+  {
+    // The native socket representation.
+    socket_type socket_;
+
+    // The current state of the socket.
+    socket_ops::state_type state_;
+
+    // We use a shared pointer as a cancellation token here to work around the
+    // broken Windows support for cancellation. MSDN says that when you call
+    // closesocket any outstanding WSARecv or WSASend operations will complete
+    // with the error ERROR_OPERATION_ABORTED. In practice they complete with
+    // ERROR_NETNAME_DELETED, which means you can't tell the difference between
+    // a local cancellation and the socket being hard-closed by the peer.
+    socket_ops::shared_cancel_token_type cancel_token_;
+
+    // Per-descriptor data used by the reactor.
+    select_reactor::per_descriptor_data reactor_data_;
+
+#if defined(ASIO_ENABLE_CANCELIO)
+    // The ID of the thread from which it is safe to cancel asynchronous
+    // operations. 0 means no asynchronous operations have been started yet.
+    // ~0 means asynchronous operations have been started from more than one
+    // thread, and cancellation is not supported for the socket.
+    DWORD safe_cancellation_thread_id_;
+#endif // defined(ASIO_ENABLE_CANCELIO)
+
+    // Pointers to adjacent socket implementations in linked list.
+    base_implementation_type* next_;
+    base_implementation_type* prev_;
+  };
+
+  // Constructor.
+  ASIO_DECL win_iocp_socket_service_base(
+      asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void base_shutdown();
+
+  // Construct a new socket implementation.
+  ASIO_DECL void construct(base_implementation_type& impl);
+
+  // Move-construct a new socket implementation.
+  ASIO_DECL void base_move_construct(base_implementation_type& impl,
+      base_implementation_type& other_impl);
+
+  // Move-assign from another socket implementation.
+  ASIO_DECL void base_move_assign(base_implementation_type& impl,
+      win_iocp_socket_service_base& other_service,
+      base_implementation_type& other_impl);
+
+  // Destroy a socket implementation.
+  ASIO_DECL void destroy(base_implementation_type& impl);
+
+  // Determine whether the socket is open.
+  bool is_open(const base_implementation_type& impl) const
+  {
+    return impl.socket_ != invalid_socket;
+  }
+
+  // Destroy a socket implementation.
+  ASIO_DECL asio::error_code close(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Release ownership of the socket.
+  ASIO_DECL socket_type release(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Cancel all operations associated with the socket.
+  ASIO_DECL asio::error_code cancel(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const base_implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return socket_ops::sockatmark(impl.socket_, ec);
+  }
+
+  // Determine the number of bytes available for reading.
+  std::size_t available(const base_implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return socket_ops::available(impl.socket_, ec);
+  }
+
+  // Place the socket into the state where it will listen for new connections.
+  asio::error_code listen(base_implementation_type& impl,
+      int backlog, asio::error_code& ec)
+  {
+    socket_ops::listen(impl.socket_, backlog, ec);
+    return ec;
+  }
+
+  // Perform an IO control command on the socket.
+  template <typename IO_Control_Command>
+  asio::error_code io_control(base_implementation_type& impl,
+      IO_Control_Command& command, asio::error_code& ec)
+  {
+    socket_ops::ioctl(impl.socket_, impl.state_, command.name(),
+        static_cast<ioctl_arg_type*>(command.data()), ec);
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the socket.
+  bool non_blocking(const base_implementation_type& impl) const
+  {
+    return (impl.state_ & socket_ops::user_set_non_blocking) != 0;
+  }
+
+  // Sets the non-blocking mode of the socket.
+  asio::error_code non_blocking(base_implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    socket_ops::set_user_non_blocking(impl.socket_, impl.state_, mode, ec);
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const base_implementation_type& impl) const
+  {
+    return (impl.state_ & socket_ops::internal_non_blocking) != 0;
+  }
+
+  // Sets the non-blocking mode of the native socket implementation.
+  asio::error_code native_non_blocking(base_implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    socket_ops::set_internal_non_blocking(impl.socket_, impl.state_, mode, ec);
+    return ec;
+  }
+
+  // Wait for the socket to become ready to read, ready to write, or to have
+  // pending error conditions.
+  asio::error_code wait(base_implementation_type& impl,
+      socket_base::wait_type w, asio::error_code& ec)
+  {
+    switch (w)
+    {
+    case socket_base::wait_read:
+      socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+      break;
+    case socket_base::wait_write:
+      socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);
+      break;
+    case socket_base::wait_error:
+      socket_ops::poll_error(impl.socket_, impl.state_, -1, ec);
+      break;
+    default:
+      ec = asio::error::invalid_argument;
+      break;
+    }
+
+    return ec;
+  }
+
+  // Asynchronously wait for the socket to become ready to read, ready to
+  // write, or to have pending error conditions.
+  template <typename Handler>
+  void async_wait(base_implementation_type& impl,
+      socket_base::wait_type w, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_wait_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_wait"));
+
+    switch (w)
+    {
+      case socket_base::wait_read:
+        start_null_buffers_receive_op(impl, 0, p.p);
+        break;
+      case socket_base::wait_write:
+        start_reactor_op(impl, select_reactor::write_op, p.p);
+        break;
+      case socket_base::wait_error:
+        start_reactor_op(impl, select_reactor::except_op, p.p);
+        break;
+      default:
+        p.p->ec_ = asio::error::invalid_argument;
+        iocp_service_.post_immediate_completion(p.p, is_continuation);
+        break;
+    }
+
+    p.v = p.p = 0;
+  }
+
+  // Send the given data to the peer. Returns the number of bytes sent.
+  template <typename ConstBufferSequence>
+  size_t send(base_implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_send(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), flags, bufs.all_empty(), ec);
+  }
+
+  // Wait until data can be sent without blocking.
+  size_t send(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous send. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_send(base_implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_send_op<ConstBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, buffers, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_send"));
+
+    buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence> bufs(buffers);
+
+    start_send_op(impl, bufs.buffers(), bufs.count(), flags,
+        (impl.state_ & socket_ops::stream_oriented) != 0 && bufs.all_empty(),
+        p.p);
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous wait until data can be sent without blocking.
+  template <typename Handler>
+  void async_send(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_send(null_buffers)"));
+
+    start_reactor_op(impl, select_reactor::write_op, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Receive some data from the peer. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  size_t receive(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_recv(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), flags, bufs.all_empty(), ec);
+  }
+
+  // Wait until data can be received without blocking.
+  size_t receive(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_recv_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.state_, impl.cancel_token_, buffers, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_receive"));
+
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    start_receive_op(impl, bufs.buffers(), bufs.count(), flags,
+        (impl.state_ & socket_ops::stream_oriented) != 0 && bufs.all_empty(),
+        p.p);
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive(base_implementation_type& impl, const null_buffers&,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_receive(null_buffers)"));
+
+    start_null_buffers_receive_op(impl, flags, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Receive some data with associated flags. Returns the number of bytes
+  // received.
+  template <typename MutableBufferSequence>
+  size_t receive_with_flags(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, asio::error_code& ec)
+  {
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    return socket_ops::sync_recvmsg(impl.socket_, impl.state_,
+        bufs.buffers(), bufs.count(), in_flags, out_flags, ec);
+  }
+
+  // Wait until data can be received without blocking.
+  size_t receive_with_flags(base_implementation_type& impl,
+      const null_buffers&, socket_base::message_flags,
+      socket_base::message_flags& out_flags, asio::error_code& ec)
+  {
+    // Wait for socket to become ready.
+    socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
+
+    // Clear out_flags, since we cannot give it any other sensible value when
+    // performing a null_buffers operation.
+    out_flags = 0;
+
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive_with_flags(base_implementation_type& impl,
+      const MutableBufferSequence& buffers, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_socket_recvmsg_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, buffers, out_flags, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_receive_with_flags"));
+
+    buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence> bufs(buffers);
+
+    start_receive_op(impl, bufs.buffers(), bufs.count(), in_flags, false, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive_with_flags(base_implementation_type& impl,
+      const null_buffers&, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef win_iocp_null_buffers_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(impl.cancel_token_, handler);
+
+    ASIO_HANDLER_CREATION((io_context_, *p.p, "socket",
+          &impl, impl.socket_, "async_receive_with_flags(null_buffers)"));
+
+    // Reset out_flags since it can be given no sensible value at this time.
+    out_flags = 0;
+
+    start_null_buffers_receive_op(impl, in_flags, p.p);
+    p.v = p.p = 0;
+  }
+
+  // Helper function to restart an asynchronous accept operation.
+  ASIO_DECL void restart_accept_op(socket_type s,
+      socket_holder& new_socket, int family, int type, int protocol,
+      void* output_buffer, DWORD address_length, operation* op);
+
+protected:
+  // Open a new socket implementation.
+  ASIO_DECL asio::error_code do_open(
+      base_implementation_type& impl, int family, int type,
+      int protocol, asio::error_code& ec);
+
+  // Assign a native socket to a socket implementation.
+  ASIO_DECL asio::error_code do_assign(
+      base_implementation_type& impl, int type,
+      socket_type native_socket, asio::error_code& ec);
+
+  // Helper function to start an asynchronous send operation.
+  ASIO_DECL void start_send_op(base_implementation_type& impl,
+      WSABUF* buffers, std::size_t buffer_count,
+      socket_base::message_flags flags, bool noop, operation* op);
+
+  // Helper function to start an asynchronous send_to operation.
+  ASIO_DECL void start_send_to_op(base_implementation_type& impl,
+      WSABUF* buffers, std::size_t buffer_count,
+      const socket_addr_type* addr, int addrlen,
+      socket_base::message_flags flags, operation* op);
+
+  // Helper function to start an asynchronous receive operation.
+  ASIO_DECL void start_receive_op(base_implementation_type& impl,
+      WSABUF* buffers, std::size_t buffer_count,
+      socket_base::message_flags flags, bool noop, operation* op);
+
+  // Helper function to start an asynchronous null_buffers receive operation.
+  ASIO_DECL void start_null_buffers_receive_op(
+      base_implementation_type& impl,
+      socket_base::message_flags flags, reactor_op* op);
+
+  // Helper function to start an asynchronous receive_from operation.
+  ASIO_DECL void start_receive_from_op(base_implementation_type& impl,
+      WSABUF* buffers, std::size_t buffer_count, socket_addr_type* addr,
+      socket_base::message_flags flags, int* addrlen, operation* op);
+
+  // Helper function to start an asynchronous accept operation.
+  ASIO_DECL void start_accept_op(base_implementation_type& impl,
+      bool peer_is_open, socket_holder& new_socket, int family, int type,
+      int protocol, void* output_buffer, DWORD address_length, operation* op);
+
+  // Start an asynchronous read or write operation using the reactor.
+  ASIO_DECL void start_reactor_op(base_implementation_type& impl,
+      int op_type, reactor_op* op);
+
+  // Start the asynchronous connect operation using the reactor.
+  ASIO_DECL void start_connect_op(base_implementation_type& impl,
+      int family, int type, const socket_addr_type* remote_addr,
+      std::size_t remote_addrlen, win_iocp_socket_connect_op_base* op);
+
+  // Helper function to close a socket when the associated object is being
+  // destroyed.
+  ASIO_DECL void close_for_destruction(base_implementation_type& impl);
+
+  // Update the ID of the thread from which cancellation is safe.
+  ASIO_DECL void update_cancellation_thread_id(
+      base_implementation_type& impl);
+
+  // Helper function to get the reactor. If no reactor has been created yet, a
+  // new one is obtained from the io_context and a pointer to it is cached in
+  // this service.
+  ASIO_DECL select_reactor& get_reactor();
+
+  // The type of a ConnectEx function pointer, as old SDKs may not provide it.
+  typedef BOOL (PASCAL *connect_ex_fn)(SOCKET,
+      const socket_addr_type*, int, void*, DWORD, DWORD*, OVERLAPPED*);
+
+  // Helper function to get the ConnectEx pointer. If no ConnectEx pointer has
+  // been obtained yet, one is obtained using WSAIoctl and the pointer is
+  // cached. Returns a null pointer if ConnectEx is not available.
+  ASIO_DECL connect_ex_fn get_connect_ex(
+      base_implementation_type& impl, int type);
+
+  // The type of a NtSetInformationFile function pointer.
+  typedef LONG (NTAPI *nt_set_info_fn)(HANDLE, ULONG_PTR*, void*, ULONG, ULONG);
+
+  // Helper function to get the NtSetInformationFile function pointer. If no
+  // NtSetInformationFile pointer has been obtained yet, one is obtained using
+  // GetProcAddress and the pointer is cached. Returns a null pointer if
+  // NtSetInformationFile is not available.
+  ASIO_DECL nt_set_info_fn get_nt_set_info();
+
+  // Helper function to emulate InterlockedCompareExchangePointer functionality
+  // for:
+  // - very old Platform SDKs; and
+  // - platform SDKs where MSVC's /Wp64 option causes spurious warnings.
+  ASIO_DECL void* interlocked_compare_exchange_pointer(
+      void** dest, void* exch, void* cmp);
+
+  // Helper function to emulate InterlockedExchangePointer functionality for:
+  // - very old Platform SDKs; and
+  // - platform SDKs where MSVC's /Wp64 option causes spurious warnings.
+  ASIO_DECL void* interlocked_exchange_pointer(void** dest, void* val);
+
+  // The io_context used to obtain the reactor, if required.
+  asio::io_context& io_context_;
+
+  // The IOCP service used for running asynchronous operations and dispatching
+  // handlers.
+  win_iocp_io_context& iocp_service_;
+
+  // The reactor used for performing connect operations. This object is created
+  // only if needed.
+  select_reactor* reactor_;
+
+  // Pointer to ConnectEx implementation.
+  void* connect_ex_;
+
+  // Pointer to NtSetInformationFile implementation.
+  void* nt_set_info_;
+
+  // Mutex to protect access to the linked list of implementations. 
+  asio::detail::mutex mutex_;
+
+  // The head of a linked list of all implementations.
+  base_implementation_type* impl_list_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_iocp_socket_service_base.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_BASE_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_thread_info.hpp b/subprojects/asio/include/asio/detail/win_iocp_thread_info.hpp
new file mode 100644
index 000000000..13181e2ec
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_thread_info.hpp
@@ -0,0 +1,34 @@
+//
+// detail/win_iocp_thread_info.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_THREAD_INFO_HPP
+#define ASIO_DETAIL_WIN_IOCP_THREAD_INFO_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/thread_info_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct win_iocp_thread_info : public thread_info_base
+{
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WIN_IOCP_THREAD_INFO_HPP
diff --git a/subprojects/asio/include/asio/detail/win_iocp_wait_op.hpp b/subprojects/asio/include/asio/detail/win_iocp_wait_op.hpp
new file mode 100644
index 000000000..472eea38a
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_iocp_wait_op.hpp
@@ -0,0 +1,121 @@
+//
+// detail/win_iocp_wait_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_IOCP_WAIT_OP_HPP
+#define ASIO_DETAIL_WIN_IOCP_WAIT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/reactor_op.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class win_iocp_wait_op : public reactor_op
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(win_iocp_wait_op);
+
+  win_iocp_wait_op(socket_ops::weak_cancel_token_type cancel_token,
+      Handler& handler)
+    : reactor_op(&win_iocp_wait_op::do_perform,
+        &win_iocp_wait_op::do_complete),
+      cancel_token_(cancel_token),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static status do_perform(reactor_op*)
+  {
+    return done;
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code& result_ec,
+      std::size_t /*bytes_transferred*/)
+  {
+    asio::error_code ec(result_ec);
+
+    // Take ownership of the operation object.
+    win_iocp_wait_op* o(static_cast<win_iocp_wait_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // The reactor may have stored a result in the operation object.
+    if (o->ec_)
+      ec = o->ec_;
+
+    // Map non-portable errors to their portable counterparts.
+    if (ec.value() == ERROR_NETNAME_DELETED)
+    {
+      if (o->cancel_token_.expired())
+        ec = asio::error::operation_aborted;
+      else
+        ec = asio::error::connection_reset;
+    }
+    else if (ec.value() == ERROR_PORT_UNREACHABLE)
+    {
+      ec = asio::error::connection_refused;
+    }
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(o->handler_, ec);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  socket_ops::weak_cancel_token_type cancel_token_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_IOCP)
+
+#endif // ASIO_DETAIL_WIN_IOCP_WAIT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/win_mutex.hpp b/subprojects/asio/include/asio/detail/win_mutex.hpp
new file mode 100644
index 000000000..ce52a2f79
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_mutex.hpp
@@ -0,0 +1,78 @@
+//
+// detail/win_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_MUTEX_HPP
+#define ASIO_DETAIL_WIN_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_lock.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_mutex
+  : private noncopyable
+{
+public:
+  typedef asio::detail::scoped_lock<win_mutex> scoped_lock;
+
+  // Constructor.
+  ASIO_DECL win_mutex();
+
+  // Destructor.
+  ~win_mutex()
+  {
+    ::DeleteCriticalSection(&crit_section_);
+  }
+
+  // Lock the mutex.
+  void lock()
+  {
+    ::EnterCriticalSection(&crit_section_);
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+    ::LeaveCriticalSection(&crit_section_);
+  }
+
+private:
+  // Initialisation must be performed in a separate function to the constructor
+  // since the compiler does not support the use of structured exceptions and
+  // C++ exceptions in the same function.
+  ASIO_DECL int do_init();
+
+  ::CRITICAL_SECTION crit_section_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_mutex.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_WIN_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/win_object_handle_service.hpp b/subprojects/asio/include/asio/detail/win_object_handle_service.hpp
new file mode 100644
index 000000000..1d8abc9c7
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_object_handle_service.hpp
@@ -0,0 +1,184 @@
+//
+// detail/win_object_handle_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2011 Boris Schaeling (boris@highscore.de)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_OBJECT_HANDLE_SERVICE_HPP
+#define ASIO_DETAIL_WIN_OBJECT_HANDLE_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/wait_handler.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class win_object_handle_service :
+  public service_base<win_object_handle_service>
+{
+public:
+  // The native type of an object handle.
+  typedef HANDLE native_handle_type;
+
+  // The implementation type of the object handle.
+  class implementation_type
+  {
+   public:
+    // Default constructor.
+    implementation_type()
+      : handle_(INVALID_HANDLE_VALUE),
+        wait_handle_(INVALID_HANDLE_VALUE),
+        owner_(0),
+        next_(0),
+        prev_(0)
+    {
+    }
+
+  private:
+    // Only this service will have access to the internal values.
+    friend class win_object_handle_service;
+
+    // The native object handle representation. May be accessed or modified
+    // without locking the mutex.
+    native_handle_type handle_;
+
+    // The handle used to unregister the wait operation. The mutex must be
+    // locked when accessing or modifying this member.
+    HANDLE wait_handle_;
+
+    // The operations waiting on the object handle. If there is a registered
+    // wait then the mutex must be locked when accessing or modifying this
+    // member
+    op_queue<wait_op> op_queue_;
+
+    // The service instance that owns the object handle implementation.
+    win_object_handle_service* owner_;
+
+    // Pointers to adjacent handle implementations in linked list. The mutex
+    // must be locked when accessing or modifying these members.
+    implementation_type* next_;
+    implementation_type* prev_;
+  };
+
+  // Constructor.
+  ASIO_DECL win_object_handle_service(
+      asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Construct a new handle implementation.
+  ASIO_DECL void construct(implementation_type& impl);
+
+  // Move-construct a new handle implementation.
+  ASIO_DECL void move_construct(implementation_type& impl,
+      implementation_type& other_impl);
+
+  // Move-assign from another handle implementation.
+  ASIO_DECL void move_assign(implementation_type& impl,
+      win_object_handle_service& other_service,
+      implementation_type& other_impl);
+
+  // Destroy a handle implementation.
+  ASIO_DECL void destroy(implementation_type& impl);
+
+  // Assign a native handle to a handle implementation.
+  ASIO_DECL asio::error_code assign(implementation_type& impl,
+      const native_handle_type& handle, asio::error_code& ec);
+
+  // Determine whether the handle is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return impl.handle_ != INVALID_HANDLE_VALUE && impl.handle_ != 0;
+  }
+
+  // Destroy a handle implementation.
+  ASIO_DECL asio::error_code close(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Get the native handle representation.
+  native_handle_type native_handle(const implementation_type& impl) const
+  {
+    return impl.handle_;
+  }
+
+  // Cancel all operations associated with the handle.
+  ASIO_DECL asio::error_code cancel(implementation_type& impl,
+      asio::error_code& ec);
+
+  // Perform a synchronous wait for the object to enter a signalled state.
+  ASIO_DECL void wait(implementation_type& impl,
+      asio::error_code& ec);
+
+  /// Start an asynchronous wait.
+  template <typename Handler>
+  void async_wait(implementation_type& impl, Handler& handler)
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef wait_handler<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((io_context_.context(), *p.p, "object_handle",
+          &impl, reinterpret_cast<uintmax_t>(impl.wait_handle_), "async_wait"));
+
+    start_wait_op(impl, p.p);
+    p.v = p.p = 0;
+  }
+
+private:
+  // Helper function to start an asynchronous wait operation.
+  ASIO_DECL void start_wait_op(implementation_type& impl, wait_op* op);
+
+  // Helper function to register a wait operation.
+  ASIO_DECL void register_wait_callback(
+      implementation_type& impl, mutex::scoped_lock& lock);
+
+  // Callback function invoked when the registered wait completes.
+  static ASIO_DECL VOID CALLBACK wait_callback(
+      PVOID param, BOOLEAN timeout);
+
+  // The io_context implementation used to post completions.
+  io_context_impl& io_context_;
+
+  // Mutex to protect access to internal state.
+  mutex mutex_;
+
+  // The head of a linked list of all implementations.
+  implementation_type* impl_list_;
+
+  // Flag to indicate that the dispatcher has been shut down.
+  bool shutdown_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_object_handle_service.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+
+#endif // ASIO_DETAIL_WIN_OBJECT_HANDLE_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/win_static_mutex.hpp b/subprojects/asio/include/asio/detail/win_static_mutex.hpp
new file mode 100644
index 000000000..b16968862
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_static_mutex.hpp
@@ -0,0 +1,74 @@
+//
+// detail/win_static_mutex.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_STATIC_MUTEX_HPP
+#define ASIO_DETAIL_WIN_STATIC_MUTEX_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include "asio/detail/scoped_lock.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct win_static_mutex
+{
+  typedef asio::detail::scoped_lock<win_static_mutex> scoped_lock;
+
+  // Initialise the mutex.
+  ASIO_DECL void init();
+
+  // Initialisation must be performed in a separate function to the "public"
+  // init() function since the compiler does not support the use of structured
+  // exceptions and C++ exceptions in the same function.
+  ASIO_DECL int do_init();
+
+  // Lock the mutex.
+  void lock()
+  {
+    ::EnterCriticalSection(&crit_section_);
+  }
+
+  // Unlock the mutex.
+  void unlock()
+  {
+    ::LeaveCriticalSection(&crit_section_);
+  }
+
+  bool initialised_;
+  ::CRITICAL_SECTION crit_section_;
+};
+
+#if defined(UNDER_CE)
+# define ASIO_WIN_STATIC_MUTEX_INIT { false, { 0, 0, 0, 0, 0 } }
+#else // defined(UNDER_CE)
+# define ASIO_WIN_STATIC_MUTEX_INIT { false, { 0, 0, 0, 0, 0, 0 } }
+#endif // defined(UNDER_CE)
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_static_mutex.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_WIN_STATIC_MUTEX_HPP
diff --git a/subprojects/asio/include/asio/detail/win_thread.hpp b/subprojects/asio/include/asio/detail/win_thread.hpp
new file mode 100644
index 000000000..8b28a90b6
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_thread.hpp
@@ -0,0 +1,147 @@
+//
+// detail/win_thread.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_THREAD_HPP
+#define ASIO_DETAIL_WIN_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) \
+  && !defined(ASIO_WINDOWS_APP) \
+  && !defined(UNDER_CE)
+
+#include <cstddef>
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+ASIO_DECL unsigned int __stdcall win_thread_function(void* arg);
+
+#if defined(WINVER) && (WINVER < 0x0500)
+ASIO_DECL void __stdcall apc_function(ULONG data);
+#else
+ASIO_DECL void __stdcall apc_function(ULONG_PTR data);
+#endif
+
+template <typename T>
+class win_thread_base
+{
+public:
+  static bool terminate_threads()
+  {
+    return ::InterlockedExchangeAdd(&terminate_threads_, 0) != 0;
+  }
+
+  static void set_terminate_threads(bool b)
+  {
+    ::InterlockedExchange(&terminate_threads_, b ? 1 : 0);
+  }
+
+private:
+  static long terminate_threads_;
+};
+
+template <typename T>
+long win_thread_base<T>::terminate_threads_ = 0;
+
+class win_thread
+  : private noncopyable,
+    public win_thread_base<win_thread>
+{
+public:
+  // Constructor.
+  template <typename Function>
+  win_thread(Function f, unsigned int stack_size = 0)
+    : thread_(0),
+      exit_event_(0)
+  {
+    start_thread(new func<Function>(f), stack_size);
+  }
+
+  // Destructor.
+  ASIO_DECL ~win_thread();
+
+  // Wait for the thread to exit.
+  ASIO_DECL void join();
+
+  // Get number of CPUs.
+  ASIO_DECL static std::size_t hardware_concurrency();
+
+private:
+  friend ASIO_DECL unsigned int __stdcall win_thread_function(void* arg);
+
+#if defined(WINVER) && (WINVER < 0x0500)
+  friend ASIO_DECL void __stdcall apc_function(ULONG);
+#else
+  friend ASIO_DECL void __stdcall apc_function(ULONG_PTR);
+#endif
+
+  class func_base
+  {
+  public:
+    virtual ~func_base() {}
+    virtual void run() = 0;
+    ::HANDLE entry_event_;
+    ::HANDLE exit_event_;
+  };
+
+  struct auto_func_base_ptr
+  {
+    func_base* ptr;
+    ~auto_func_base_ptr() { delete ptr; }
+  };
+
+  template <typename Function>
+  class func
+    : public func_base
+  {
+  public:
+    func(Function f)
+      : f_(f)
+    {
+    }
+
+    virtual void run()
+    {
+      f_();
+    }
+
+  private:
+    Function f_;
+  };
+
+  ASIO_DECL void start_thread(func_base* arg, unsigned int stack_size);
+
+  ::HANDLE thread_;
+  ::HANDLE exit_event_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_thread.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS)
+       // && !defined(ASIO_WINDOWS_APP)
+       // && !defined(UNDER_CE)
+
+#endif // ASIO_DETAIL_WIN_THREAD_HPP
diff --git a/subprojects/asio/include/asio/detail/win_tss_ptr.hpp b/subprojects/asio/include/asio/detail/win_tss_ptr.hpp
new file mode 100644
index 000000000..4207108a3
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/win_tss_ptr.hpp
@@ -0,0 +1,79 @@
+//
+// detail/win_tss_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WIN_TSS_PTR_HPP
+#define ASIO_DETAIL_WIN_TSS_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+// Helper function to create thread-specific storage.
+ASIO_DECL DWORD win_tss_ptr_create();
+
+template <typename T>
+class win_tss_ptr
+  : private noncopyable
+{
+public:
+  // Constructor.
+  win_tss_ptr()
+    : tss_key_(win_tss_ptr_create())
+  {
+  }
+
+  // Destructor.
+  ~win_tss_ptr()
+  {
+    ::TlsFree(tss_key_);
+  }
+
+  // Get the value.
+  operator T*() const
+  {
+    return static_cast<T*>(::TlsGetValue(tss_key_));
+  }
+
+  // Set the value.
+  void operator=(T* value)
+  {
+    ::TlsSetValue(tss_key_, value);
+  }
+
+private:
+  // Thread-specific storage to allow unlocked access to determine whether a
+  // thread is a member of the pool.
+  DWORD tss_key_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/win_tss_ptr.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS)
+
+#endif // ASIO_DETAIL_WIN_TSS_PTR_HPP
diff --git a/subprojects/asio/include/asio/detail/winapp_thread.hpp b/subprojects/asio/include/asio/detail/winapp_thread.hpp
new file mode 100644
index 000000000..69dcf08d4
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winapp_thread.hpp
@@ -0,0 +1,124 @@
+//
+// detail/winapp_thread.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINAPP_THREAD_HPP
+#define ASIO_DETAIL_WINAPP_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) && defined(ASIO_WINDOWS_APP)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+DWORD WINAPI winapp_thread_function(LPVOID arg);
+
+class winapp_thread
+  : private noncopyable
+{
+public:
+  // Constructor.
+  template <typename Function>
+  winapp_thread(Function f, unsigned int = 0)
+  {
+    scoped_ptr<func_base> arg(new func<Function>(f));
+    DWORD thread_id = 0;
+    thread_ = ::CreateThread(0, 0, winapp_thread_function,
+        arg.get(), 0, &thread_id);
+    if (!thread_)
+    {
+      DWORD last_error = ::GetLastError();
+      asio::error_code ec(last_error,
+          asio::error::get_system_category());
+      asio::detail::throw_error(ec, "thread");
+    }
+    arg.release();
+  }
+
+  // Destructor.
+  ~winapp_thread()
+  {
+    ::CloseHandle(thread_);
+  }
+
+  // Wait for the thread to exit.
+  void join()
+  {
+    ::WaitForSingleObjectEx(thread_, INFINITE, false);
+  }
+
+  // Get number of CPUs.
+  static std::size_t hardware_concurrency()
+  {
+    SYSTEM_INFO system_info;
+    ::GetNativeSystemInfo(&system_info);
+    return system_info.dwNumberOfProcessors;
+  }
+
+private:
+  friend DWORD WINAPI winapp_thread_function(LPVOID arg);
+
+  class func_base
+  {
+  public:
+    virtual ~func_base() {}
+    virtual void run() = 0;
+  };
+
+  template <typename Function>
+  class func
+    : public func_base
+  {
+  public:
+    func(Function f)
+      : f_(f)
+    {
+    }
+
+    virtual void run()
+    {
+      f_();
+    }
+
+  private:
+    Function f_;
+  };
+
+  ::HANDLE thread_;
+};
+
+inline DWORD WINAPI winapp_thread_function(LPVOID arg)
+{
+  scoped_ptr<winapp_thread::func_base> func(
+      static_cast<winapp_thread::func_base*>(arg));
+  func->run();
+  return 0;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS) && defined(ASIO_WINDOWS_APP)
+
+#endif // ASIO_DETAIL_WINAPP_THREAD_HPP
diff --git a/subprojects/asio/include/asio/detail/wince_thread.hpp b/subprojects/asio/include/asio/detail/wince_thread.hpp
new file mode 100644
index 000000000..a2863f625
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/wince_thread.hpp
@@ -0,0 +1,124 @@
+//
+// detail/wince_thread.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINCE_THREAD_HPP
+#define ASIO_DETAIL_WINCE_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) && defined(UNDER_CE)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+DWORD WINAPI wince_thread_function(LPVOID arg);
+
+class wince_thread
+  : private noncopyable
+{
+public:
+  // Constructor.
+  template <typename Function>
+  wince_thread(Function f, unsigned int = 0)
+  {
+    scoped_ptr<func_base> arg(new func<Function>(f));
+    DWORD thread_id = 0;
+    thread_ = ::CreateThread(0, 0, wince_thread_function,
+        arg.get(), 0, &thread_id);
+    if (!thread_)
+    {
+      DWORD last_error = ::GetLastError();
+      asio::error_code ec(last_error,
+          asio::error::get_system_category());
+      asio::detail::throw_error(ec, "thread");
+    }
+    arg.release();
+  }
+
+  // Destructor.
+  ~wince_thread()
+  {
+    ::CloseHandle(thread_);
+  }
+
+  // Wait for the thread to exit.
+  void join()
+  {
+    ::WaitForSingleObject(thread_, INFINITE);
+  }
+
+  // Get number of CPUs.
+  static std::size_t hardware_concurrency()
+  {
+    SYSTEM_INFO system_info;
+    ::GetSystemInfo(&system_info);
+    return system_info.dwNumberOfProcessors;
+  }
+
+private:
+  friend DWORD WINAPI wince_thread_function(LPVOID arg);
+
+  class func_base
+  {
+  public:
+    virtual ~func_base() {}
+    virtual void run() = 0;
+  };
+
+  template <typename Function>
+  class func
+    : public func_base
+  {
+  public:
+    func(Function f)
+      : f_(f)
+    {
+    }
+
+    virtual void run()
+    {
+      f_();
+    }
+
+  private:
+    Function f_;
+  };
+
+  ::HANDLE thread_;
+};
+
+inline DWORD WINAPI wince_thread_function(LPVOID arg)
+{
+  scoped_ptr<wince_thread::func_base> func(
+      static_cast<wince_thread::func_base*>(arg));
+  func->run();
+  return 0;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS) && defined(UNDER_CE)
+
+#endif // ASIO_DETAIL_WINCE_THREAD_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_async_manager.hpp b/subprojects/asio/include/asio/detail/winrt_async_manager.hpp
new file mode 100644
index 000000000..e22ad52e2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_async_manager.hpp
@@ -0,0 +1,294 @@
+//
+// detail/winrt_async_manager.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_ASYNC_MANAGER_HPP
+#define ASIO_DETAIL_WINRT_ASYNC_MANAGER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include <future>
+#include "asio/detail/atomic_count.hpp"
+#include "asio/detail/winrt_async_op.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class winrt_async_manager
+  : public asio::detail::service_base<winrt_async_manager>
+{
+public:
+  // Constructor.
+  winrt_async_manager(asio::io_context& io_context)
+    : asio::detail::service_base<winrt_async_manager>(io_context),
+      io_context_(use_service<io_context_impl>(io_context)),
+      outstanding_ops_(1)
+  {
+  }
+
+  // Destructor.
+  ~winrt_async_manager()
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    if (--outstanding_ops_ > 0)
+    {
+      // Block until last operation is complete.
+      std::future<void> f = promise_.get_future();
+      f.wait();
+    }
+  }
+
+  void sync(Windows::Foundation::IAsyncAction^ action,
+      asio::error_code& ec)
+  {
+    using namespace Windows::Foundation;
+    using Windows::Foundation::AsyncStatus;
+
+    auto promise = std::make_shared<std::promise<asio::error_code>>();
+    auto future = promise->get_future();
+
+    action->Completed = ref new AsyncActionCompletedHandler(
+      [promise](IAsyncAction^ action, AsyncStatus status)
+      {
+        switch (status)
+        {
+        case AsyncStatus::Canceled:
+          promise->set_value(asio::error::operation_aborted);
+          break;
+        case AsyncStatus::Error:
+        case AsyncStatus::Completed:
+        default:
+          asio::error_code ec(
+              action->ErrorCode.Value,
+              asio::system_category());
+          promise->set_value(ec);
+          break;
+        }
+      });
+
+    ec = future.get();
+  }
+
+  template <typename TResult>
+  TResult sync(Windows::Foundation::IAsyncOperation<TResult>^ operation,
+      asio::error_code& ec)
+  {
+    using namespace Windows::Foundation;
+    using Windows::Foundation::AsyncStatus;
+
+    auto promise = std::make_shared<std::promise<asio::error_code>>();
+    auto future = promise->get_future();
+
+    operation->Completed = ref new AsyncOperationCompletedHandler<TResult>(
+      [promise](IAsyncOperation<TResult>^ operation, AsyncStatus status)
+      {
+        switch (status)
+        {
+        case AsyncStatus::Canceled:
+          promise->set_value(asio::error::operation_aborted);
+          break;
+        case AsyncStatus::Error:
+        case AsyncStatus::Completed:
+        default:
+          asio::error_code ec(
+              operation->ErrorCode.Value,
+              asio::system_category());
+          promise->set_value(ec);
+          break;
+        }
+      });
+
+    ec = future.get();
+    return operation->GetResults();
+  }
+
+  template <typename TResult, typename TProgress>
+  TResult sync(
+      Windows::Foundation::IAsyncOperationWithProgress<
+        TResult, TProgress>^ operation,
+      asio::error_code& ec)
+  {
+    using namespace Windows::Foundation;
+    using Windows::Foundation::AsyncStatus;
+
+    auto promise = std::make_shared<std::promise<asio::error_code>>();
+    auto future = promise->get_future();
+
+    operation->Completed
+      = ref new AsyncOperationWithProgressCompletedHandler<TResult, TProgress>(
+        [promise](IAsyncOperationWithProgress<TResult, TProgress>^ operation,
+          AsyncStatus status)
+        {
+          switch (status)
+          {
+          case AsyncStatus::Canceled:
+            promise->set_value(asio::error::operation_aborted);
+            break;
+          case AsyncStatus::Started:
+            break;
+          case AsyncStatus::Error:
+          case AsyncStatus::Completed:
+          default:
+            asio::error_code ec(
+                operation->ErrorCode.Value,
+                asio::system_category());
+            promise->set_value(ec);
+            break;
+          }
+        });
+
+    ec = future.get();
+    return operation->GetResults();
+  }
+
+  void async(Windows::Foundation::IAsyncAction^ action,
+      winrt_async_op<void>* handler)
+  {
+    using namespace Windows::Foundation;
+    using Windows::Foundation::AsyncStatus;
+
+    auto on_completed = ref new AsyncActionCompletedHandler(
+      [this, handler](IAsyncAction^ action, AsyncStatus status)
+      {
+        switch (status)
+        {
+        case AsyncStatus::Canceled:
+          handler->ec_ = asio::error::operation_aborted;
+          break;
+        case AsyncStatus::Started:
+          return;
+        case AsyncStatus::Completed:
+        case AsyncStatus::Error:
+        default:
+          handler->ec_ = asio::error_code(
+              action->ErrorCode.Value,
+              asio::system_category());
+          break;
+        }
+        io_context_.post_deferred_completion(handler);
+        if (--outstanding_ops_ == 0)
+          promise_.set_value();
+      });
+
+    io_context_.work_started();
+    ++outstanding_ops_;
+    action->Completed = on_completed;
+  }
+
+  template <typename TResult>
+  void async(Windows::Foundation::IAsyncOperation<TResult>^ operation,
+      winrt_async_op<TResult>* handler)
+  {
+    using namespace Windows::Foundation;
+    using Windows::Foundation::AsyncStatus;
+
+    auto on_completed = ref new AsyncOperationCompletedHandler<TResult>(
+      [this, handler](IAsyncOperation<TResult>^ operation, AsyncStatus status)
+      {
+        switch (status)
+        {
+        case AsyncStatus::Canceled:
+          handler->ec_ = asio::error::operation_aborted;
+          break;
+        case AsyncStatus::Started:
+          return;
+        case AsyncStatus::Completed:
+          handler->result_ = operation->GetResults();
+          // Fall through.
+        case AsyncStatus::Error:
+        default:
+          handler->ec_ = asio::error_code(
+              operation->ErrorCode.Value,
+              asio::system_category());
+          break;
+        }
+        io_context_.post_deferred_completion(handler);
+        if (--outstanding_ops_ == 0)
+          promise_.set_value();
+      });
+
+    io_context_.work_started();
+    ++outstanding_ops_;
+    operation->Completed = on_completed;
+  }
+
+  template <typename TResult, typename TProgress>
+  void async(
+      Windows::Foundation::IAsyncOperationWithProgress<
+        TResult, TProgress>^ operation,
+      winrt_async_op<TResult>* handler)
+  {
+    using namespace Windows::Foundation;
+    using Windows::Foundation::AsyncStatus;
+
+    auto on_completed
+      = ref new AsyncOperationWithProgressCompletedHandler<TResult, TProgress>(
+        [this, handler](IAsyncOperationWithProgress<
+          TResult, TProgress>^ operation, AsyncStatus status)
+        {
+          switch (status)
+          {
+          case AsyncStatus::Canceled:
+            handler->ec_ = asio::error::operation_aborted;
+            break;
+          case AsyncStatus::Started:
+            return;
+          case AsyncStatus::Completed:
+            handler->result_ = operation->GetResults();
+            // Fall through.
+          case AsyncStatus::Error:
+          default:
+            handler->ec_ = asio::error_code(
+                operation->ErrorCode.Value,
+                asio::system_category());
+            break;
+          }
+          io_context_.post_deferred_completion(handler);
+          if (--outstanding_ops_ == 0)
+            promise_.set_value();
+        });
+
+    io_context_.work_started();
+    ++outstanding_ops_;
+    operation->Completed = on_completed;
+  }
+
+private:
+  // The io_context implementation used to post completed handlers.
+  io_context_impl& io_context_;
+
+  // Count of outstanding operations.
+  atomic_count outstanding_ops_;
+
+  // Used to keep wait for outstanding operations to complete.
+  std::promise<void> promise_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_ASYNC_MANAGER_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_async_op.hpp b/subprojects/asio/include/asio/detail/winrt_async_op.hpp
new file mode 100644
index 000000000..75891a4ad
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_async_op.hpp
@@ -0,0 +1,65 @@
+//
+// detail/winrt_async_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_ASYNC_OP_HPP
+#define ASIO_DETAIL_WINRT_ASYNC_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/operation.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename TResult>
+class winrt_async_op
+  : public operation
+{
+public:
+  // The error code to be passed to the completion handler.
+  asio::error_code ec_;
+
+  // The result of the operation, to be passed to the completion handler.
+  TResult result_;
+
+protected:
+  winrt_async_op(func_type complete_func)
+    : operation(complete_func),
+      result_()
+  {
+  }
+};
+
+template <>
+class winrt_async_op<void>
+  : public operation
+{
+public:
+  // The error code to be passed to the completion handler.
+  asio::error_code ec_;
+
+protected:
+  winrt_async_op(func_type complete_func)
+    : operation(complete_func)
+  {
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WINRT_ASYNC_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_resolve_op.hpp b/subprojects/asio/include/asio/detail/winrt_resolve_op.hpp
new file mode 100644
index 000000000..07efd29d2
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_resolve_op.hpp
@@ -0,0 +1,118 @@
+//
+// detail/winrt_resolve_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_RESOLVE_OP_HPP
+#define ASIO_DETAIL_WINRT_RESOLVE_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/winrt_async_op.hpp"
+#include "asio/ip/basic_resolver_results.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol, typename Handler>
+class winrt_resolve_op :
+  public winrt_async_op<
+    Windows::Foundation::Collections::IVectorView<
+      Windows::Networking::EndpointPair^>^>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(winrt_resolve_op);
+
+  typedef typename Protocol::endpoint endpoint_type;
+  typedef asio::ip::basic_resolver_query<Protocol> query_type;
+  typedef asio::ip::basic_resolver_results<Protocol> results_type;
+
+  winrt_resolve_op(const query_type& query, Handler& handler)
+    : winrt_async_op<
+        Windows::Foundation::Collections::IVectorView<
+          Windows::Networking::EndpointPair^>^>(
+            &winrt_resolve_op::do_complete),
+      query_(query),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code&, std::size_t)
+  {
+    // Take ownership of the operation object.
+    winrt_resolve_op* o(static_cast<winrt_resolve_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    results_type results = results_type();
+    if (!o->ec_)
+    {
+      try
+      {
+        results = results_type::create(o->result_, o->query_.hints(),
+            o->query_.host_name(), o->query_.service_name());
+      }
+      catch (Platform::Exception^ e)
+      {
+        o->ec_ = asio::error_code(e->HResult,
+            asio::system_category());
+      }
+    }
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, results_type>
+      handler(o->handler_, o->ec_, results);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  query_type query_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_RESOLVE_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_resolver_service.hpp b/subprojects/asio/include/asio/detail/winrt_resolver_service.hpp
new file mode 100644
index 000000000..aeb44485e
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_resolver_service.hpp
@@ -0,0 +1,198 @@
+//
+// detail/winrt_resolver_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_RESOLVER_SERVICE_HPP
+#define ASIO_DETAIL_WINRT_RESOLVER_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/ip/basic_resolver_query.hpp"
+#include "asio/ip/basic_resolver_results.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/winrt_async_manager.hpp"
+#include "asio/detail/winrt_resolve_op.hpp"
+#include "asio/detail/winrt_utils.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol>
+class winrt_resolver_service :
+  public service_base<winrt_resolver_service<Protocol> >
+{
+public:
+  // The implementation type of the resolver. A cancellation token is used to
+  // indicate to the asynchronous operation that the operation has been
+  // cancelled.
+  typedef socket_ops::shared_cancel_token_type implementation_type;
+
+  // The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  // The query type.
+  typedef asio::ip::basic_resolver_query<Protocol> query_type;
+
+  // The results type.
+  typedef asio::ip::basic_resolver_results<Protocol> results_type;
+
+  // Constructor.
+  winrt_resolver_service(asio::io_context& io_context)
+    : service_base<winrt_resolver_service<Protocol> >(io_context),
+      io_context_(use_service<io_context_impl>(io_context)),
+      async_manager_(use_service<winrt_async_manager>(io_context))
+  {
+  }
+
+  // Destructor.
+  ~winrt_resolver_service()
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+  }
+
+  // Perform any fork-related housekeeping.
+  void notify_fork(asio::io_context::fork_event)
+  {
+  }
+
+  // Construct a new resolver implementation.
+  void construct(implementation_type&)
+  {
+  }
+
+  // Move-construct a new resolver implementation.
+  void move_construct(implementation_type&,
+      implementation_type&)
+  {
+  }
+
+  // Move-assign from another resolver implementation.
+  void move_assign(implementation_type&,
+      winrt_resolver_service&, implementation_type&)
+  {
+  }
+
+  // Destroy a resolver implementation.
+  void destroy(implementation_type&)
+  {
+  }
+
+  // Cancel pending asynchronous operations.
+  void cancel(implementation_type&)
+  {
+  }
+
+  // Resolve a query to a list of entries.
+  results_type resolve(implementation_type&,
+      const query_type& query, asio::error_code& ec)
+  {
+    try
+    {
+      using namespace Windows::Networking::Sockets;
+      auto endpoint_pairs = async_manager_.sync(
+          DatagramSocket::GetEndpointPairsAsync(
+            winrt_utils::host_name(query.host_name()),
+            winrt_utils::string(query.service_name())), ec);
+
+      if (ec)
+        return results_type();
+
+      return results_type::create(
+          endpoint_pairs, query.hints(),
+          query.host_name(), query.service_name());
+    }
+    catch (Platform::Exception^ e)
+    {
+      ec = asio::error_code(e->HResult,
+          asio::system_category());
+      return results_type();
+    }
+  }
+
+  // Asynchronously resolve a query to a list of entries.
+  template <typename Handler>
+  void async_resolve(implementation_type& impl,
+      const query_type& query, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef winrt_resolve_op<Protocol, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(query, handler);
+
+    ASIO_HANDLER_CREATION((io_context_.context(),
+          *p.p, "resolver", &impl, 0, "async_resolve"));
+    (void)impl;
+
+    try
+    {
+      using namespace Windows::Networking::Sockets;
+      async_manager_.async(DatagramSocket::GetEndpointPairsAsync(
+            winrt_utils::host_name(query.host_name()),
+            winrt_utils::string(query.service_name())), p.p);
+      p.v = p.p = 0;
+    }
+    catch (Platform::Exception^ e)
+    {
+      p.p->ec_ = asio::error_code(
+          e->HResult, asio::system_category());
+      io_context_.post_immediate_completion(p.p, is_continuation);
+      p.v = p.p = 0;
+    }
+  }
+
+  // Resolve an endpoint to a list of entries.
+  results_type resolve(implementation_type&,
+      const endpoint_type&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return results_type();
+  }
+
+  // Asynchronously resolve an endpoint to a list of entries.
+  template <typename Handler>
+  void async_resolve(implementation_type&,
+      const endpoint_type&, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const results_type results;
+    io_context_.get_io_context().post(
+        detail::bind_handler(handler, ec, results));
+  }
+
+private:
+  io_context_impl& io_context_;
+  winrt_async_manager& async_manager_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_RESOLVER_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_socket_connect_op.hpp b/subprojects/asio/include/asio/detail/winrt_socket_connect_op.hpp
new file mode 100644
index 000000000..f18b445f8
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_socket_connect_op.hpp
@@ -0,0 +1,92 @@
+//
+// detail/winrt_socket_connect_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_SOCKET_CONNECT_OP_HPP
+#define ASIO_DETAIL_WINRT_SOCKET_CONNECT_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/winrt_async_op.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class winrt_socket_connect_op :
+  public winrt_async_op<void>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(winrt_socket_connect_op);
+
+  winrt_socket_connect_op(Handler& handler)
+    : winrt_async_op<void>(&winrt_socket_connect_op::do_complete),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code&, std::size_t)
+  {
+    // Take ownership of the operation object.
+    winrt_socket_connect_op* o(static_cast<winrt_socket_connect_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder1<Handler, asio::error_code>
+      handler(o->handler_, o->ec_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_SOCKET_CONNECT_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_socket_recv_op.hpp b/subprojects/asio/include/asio/detail/winrt_socket_recv_op.hpp
new file mode 100644
index 000000000..8f1fcf576
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_socket_recv_op.hpp
@@ -0,0 +1,112 @@
+//
+// detail/winrt_socket_recv_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_SOCKET_RECV_OP_HPP
+#define ASIO_DETAIL_WINRT_SOCKET_RECV_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/winrt_async_op.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename MutableBufferSequence, typename Handler>
+class winrt_socket_recv_op :
+  public winrt_async_op<Windows::Storage::Streams::IBuffer^>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(winrt_socket_recv_op);
+
+  winrt_socket_recv_op(const MutableBufferSequence& buffers, Handler& handler)
+    : winrt_async_op<Windows::Storage::Streams::IBuffer^>(
+          &winrt_socket_recv_op::do_complete),
+      buffers_(buffers),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code&, std::size_t)
+  {
+    // Take ownership of the operation object.
+    winrt_socket_recv_op* o(static_cast<winrt_socket_recv_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    // Check whether buffers are still valid.
+    if (owner)
+    {
+      buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    std::size_t bytes_transferred = o->result_ ? o->result_->Length : 0;
+    if (bytes_transferred == 0 && !o->ec_ &&
+        !buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::all_empty(o->buffers_))
+    {
+      o->ec_ = asio::error::eof;
+    }
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, bytes_transferred);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  MutableBufferSequence buffers_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_SOCKET_RECV_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_socket_send_op.hpp b/subprojects/asio/include/asio/detail/winrt_socket_send_op.hpp
new file mode 100644
index 000000000..1148c24e4
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_socket_send_op.hpp
@@ -0,0 +1,103 @@
+//
+// detail/winrt_socket_send_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_SOCKET_SEND_OP_HPP
+#define ASIO_DETAIL_WINRT_SOCKET_SEND_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/winrt_async_op.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename ConstBufferSequence, typename Handler>
+class winrt_socket_send_op :
+  public winrt_async_op<unsigned int>
+{
+public:
+  ASIO_DEFINE_HANDLER_PTR(winrt_socket_send_op);
+
+  winrt_socket_send_op(const ConstBufferSequence& buffers, Handler& handler)
+    : winrt_async_op<unsigned int>(&winrt_socket_send_op::do_complete),
+      buffers_(buffers),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+    handler_work<Handler>::start(handler_);
+  }
+
+  static void do_complete(void* owner, operation* base,
+      const asio::error_code&, std::size_t)
+  {
+    // Take ownership of the operation object.
+    winrt_socket_send_op* o(static_cast<winrt_socket_send_op*>(base));
+    ptr p = { asio::detail::addressof(o->handler_), o, o };
+    handler_work<Handler> w(o->handler_);
+
+    ASIO_HANDLER_COMPLETION((*o));
+
+#if defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+    // Check whether buffers are still valid.
+    if (owner)
+    {
+      buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::validate(o->buffers_);
+    }
+#endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
+
+    // Make a copy of the handler so that the memory can be deallocated before
+    // the upcall is made. Even if we're not about to make an upcall, a
+    // sub-object of the handler may be the true owner of the memory associated
+    // with the handler. Consequently, a local copy of the handler is required
+    // to ensure that any owning sub-object remains valid until after we have
+    // deallocated the memory here.
+    detail::binder2<Handler, asio::error_code, std::size_t>
+      handler(o->handler_, o->ec_, o->result_);
+    p.h = asio::detail::addressof(handler.handler_);
+    p.reset();
+
+    // Make the upcall if required.
+    if (owner)
+    {
+      fenced_block b(fenced_block::half);
+      ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
+      w.complete(handler, handler.handler_);
+      ASIO_HANDLER_INVOCATION_END;
+    }
+  }
+
+private:
+  ConstBufferSequence buffers_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_SOCKET_SEND_OP_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_ssocket_service.hpp b/subprojects/asio/include/asio/detail/winrt_ssocket_service.hpp
new file mode 100644
index 000000000..603724a30
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_ssocket_service.hpp
@@ -0,0 +1,241 @@
+//
+// detail/winrt_ssocket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_SSOCKET_SERVICE_HPP
+#define ASIO_DETAIL_WINRT_SSOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/winrt_socket_connect_op.hpp"
+#include "asio/detail/winrt_ssocket_service_base.hpp"
+#include "asio/detail/winrt_utils.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Protocol>
+class winrt_ssocket_service :
+  public service_base<winrt_ssocket_service<Protocol> >,
+  public winrt_ssocket_service_base
+{
+public:
+  // The protocol type.
+  typedef Protocol protocol_type;
+
+  // The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+  // The native type of a socket.
+  typedef Windows::Networking::Sockets::StreamSocket^ native_handle_type;
+
+  // The implementation type of the socket.
+  struct implementation_type : base_implementation_type
+  {
+    // Default constructor.
+    implementation_type()
+      : base_implementation_type(),
+        protocol_(endpoint_type().protocol())
+    {
+    }
+
+    // The protocol associated with the socket.
+    protocol_type protocol_;
+  };
+
+  // Constructor.
+  winrt_ssocket_service(asio::io_context& io_context)
+    : service_base<winrt_ssocket_service<Protocol> >(io_context),
+      winrt_ssocket_service_base(io_context)
+  {
+  }
+
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    this->base_shutdown();
+  }
+
+  // Move-construct a new socket implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    this->base_move_construct(impl, other_impl);
+
+    impl.protocol_ = other_impl.protocol_;
+    other_impl.protocol_ = endpoint_type().protocol();
+  }
+
+  // Move-assign from another socket implementation.
+  void move_assign(implementation_type& impl,
+      winrt_ssocket_service& other_service,
+      implementation_type& other_impl)
+  {
+    this->base_move_assign(impl, other_service, other_impl);
+
+    impl.protocol_ = other_impl.protocol_;
+    other_impl.protocol_ = endpoint_type().protocol();
+  }
+
+  // Move-construct a new socket implementation from another protocol type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      winrt_ssocket_service<Protocol1>&,
+      typename winrt_ssocket_service<
+        Protocol1>::implementation_type& other_impl)
+  {
+    this->base_move_construct(impl, other_impl);
+
+    impl.protocol_ = protocol_type(other_impl.protocol_);
+    other_impl.protocol_ = typename Protocol1::endpoint().protocol();
+  }
+
+  // Open a new socket implementation.
+  asio::error_code open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    if (is_open(impl))
+    {
+      ec = asio::error::already_open;
+      return ec;
+    }
+
+    try
+    {
+      impl.socket_ = ref new Windows::Networking::Sockets::StreamSocket;
+      impl.protocol_ = protocol;
+      ec = asio::error_code();
+    }
+    catch (Platform::Exception^ e)
+    {
+      ec = asio::error_code(e->HResult,
+            asio::system_category());
+    }
+
+    return ec;
+  }
+
+  // Assign a native socket to a socket implementation.
+  asio::error_code assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_socket,
+      asio::error_code& ec)
+  {
+    if (is_open(impl))
+    {
+      ec = asio::error::already_open;
+      return ec;
+    }
+
+    impl.socket_ = native_socket;
+    impl.protocol_ = protocol;
+    ec = asio::error_code();
+
+    return ec;
+  }
+
+  // Bind the socket to the specified local endpoint.
+  asio::error_code bind(implementation_type&,
+      const endpoint_type&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    endpoint_type endpoint;
+    endpoint.resize(do_get_endpoint(impl, true,
+          endpoint.data(), endpoint.size(), ec));
+    return endpoint;
+  }
+
+  // Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    endpoint_type endpoint;
+    endpoint.resize(do_get_endpoint(impl, false,
+          endpoint.data(), endpoint.size(), ec));
+    return endpoint;
+  }
+
+  // Set a socket option.
+  template <typename Option>
+  asio::error_code set_option(implementation_type& impl,
+      const Option& option, asio::error_code& ec)
+  {
+    return do_set_option(impl, option.level(impl.protocol_),
+        option.name(impl.protocol_), option.data(impl.protocol_),
+        option.size(impl.protocol_), ec);
+  }
+
+  // Get a socket option.
+  template <typename Option>
+  asio::error_code get_option(const implementation_type& impl,
+      Option& option, asio::error_code& ec) const
+  {
+    std::size_t size = option.size(impl.protocol_);
+    do_get_option(impl, option.level(impl.protocol_),
+        option.name(impl.protocol_),
+        option.data(impl.protocol_), &size, ec);
+    if (!ec)
+      option.resize(impl.protocol_, size);
+    return ec;
+  }
+
+  // Connect the socket to the specified endpoint.
+  asio::error_code connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    return do_connect(impl, peer_endpoint.data(), ec);
+  }
+
+  // Start an asynchronous connect.
+  template <typename Handler>
+  void async_connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef winrt_socket_connect_op<Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(handler);
+
+    ASIO_HANDLER_CREATION((io_context_.context(),
+          *p.p, "socket", &impl, 0, "async_connect"));
+
+    start_connect_op(impl, peer_endpoint.data(), p.p, is_continuation);
+    p.v = p.p = 0;
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_SSOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_ssocket_service_base.hpp b/subprojects/asio/include/asio/detail/winrt_ssocket_service_base.hpp
new file mode 100644
index 000000000..61328d0a0
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_ssocket_service_base.hpp
@@ -0,0 +1,359 @@
+//
+// detail/winrt_ssocket_service_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_SSOCKET_SERVICE_BASE_HPP
+#define ASIO_DETAIL_WINRT_SSOCKET_SERVICE_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/buffer.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/socket_base.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/winrt_async_manager.hpp"
+#include "asio/detail/winrt_socket_recv_op.hpp"
+#include "asio/detail/winrt_socket_send_op.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class winrt_ssocket_service_base
+{
+public:
+  // The native type of a socket.
+  typedef Windows::Networking::Sockets::StreamSocket^ native_handle_type;
+
+  // The implementation type of the socket.
+  struct base_implementation_type
+  {
+    // Default constructor.
+    base_implementation_type()
+      : socket_(nullptr),
+        next_(0),
+        prev_(0)
+    {
+    }
+
+    // The underlying native socket.
+    native_handle_type socket_;
+
+    // Pointers to adjacent socket implementations in linked list.
+    base_implementation_type* next_;
+    base_implementation_type* prev_;
+  };
+
+  // Constructor.
+  ASIO_DECL winrt_ssocket_service_base(
+      asio::io_context& io_context);
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void base_shutdown();
+
+  // Construct a new socket implementation.
+  ASIO_DECL void construct(base_implementation_type&);
+
+  // Move-construct a new socket implementation.
+  ASIO_DECL void base_move_construct(base_implementation_type& impl,
+      base_implementation_type& other_impl);
+
+  // Move-assign from another socket implementation.
+  ASIO_DECL void base_move_assign(base_implementation_type& impl,
+      winrt_ssocket_service_base& other_service,
+      base_implementation_type& other_impl);
+
+  // Destroy a socket implementation.
+  ASIO_DECL void destroy(base_implementation_type& impl);
+
+  // Determine whether the socket is open.
+  bool is_open(const base_implementation_type& impl) const
+  {
+    return impl.socket_ != nullptr;
+  }
+
+  // Destroy a socket implementation.
+  ASIO_DECL asio::error_code close(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Release ownership of the socket.
+  ASIO_DECL native_handle_type release(
+      base_implementation_type& impl, asio::error_code& ec);
+
+  // Get the native socket representation.
+  native_handle_type native_handle(base_implementation_type& impl)
+  {
+    return impl.socket_;
+  }
+
+  // Cancel all operations associated with the socket.
+  asio::error_code cancel(base_implementation_type&,
+      asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const base_implementation_type&,
+      asio::error_code& ec) const
+  {
+    ec = asio::error::operation_not_supported;
+    return false;
+  }
+
+  // Determine the number of bytes available for reading.
+  std::size_t available(const base_implementation_type&,
+      asio::error_code& ec) const
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Perform an IO control command on the socket.
+  template <typename IO_Control_Command>
+  asio::error_code io_control(base_implementation_type&,
+      IO_Control_Command&, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the socket.
+  bool non_blocking(const base_implementation_type&) const
+  {
+    return false;
+  }
+
+  // Sets the non-blocking mode of the socket.
+  asio::error_code non_blocking(base_implementation_type&,
+      bool, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const base_implementation_type&) const
+  {
+    return false;
+  }
+
+  // Sets the non-blocking mode of the native socket implementation.
+  asio::error_code native_non_blocking(base_implementation_type&,
+      bool, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Disable sends or receives on the socket.
+  asio::error_code shutdown(base_implementation_type&,
+      socket_base::shutdown_type, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return ec;
+  }
+
+  // Send the given data to the peer.
+  template <typename ConstBufferSequence>
+  std::size_t send(base_implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return do_send(impl,
+        buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::first(buffers), flags, ec);
+  }
+
+  // Wait until data can be sent without blocking.
+  std::size_t send(base_implementation_type&, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Start an asynchronous send. The data being sent must be valid for the
+  // lifetime of the asynchronous operation.
+  template <typename ConstBufferSequence, typename Handler>
+  void async_send(base_implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef winrt_socket_send_op<ConstBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(buffers, handler);
+
+    ASIO_HANDLER_CREATION((io_context_.context(),
+          *p.p, "socket", &impl, 0, "async_send"));
+
+    start_send_op(impl,
+        buffer_sequence_adapter<asio::const_buffer,
+          ConstBufferSequence>::first(buffers),
+        flags, p.p, is_continuation);
+    p.v = p.p = 0;
+  }
+
+  // Start an asynchronous wait until data can be sent without blocking.
+  template <typename Handler>
+  void async_send(base_implementation_type&, const null_buffers&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.get_io_context().post(
+        detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+  // Receive some data from the peer. Returns the number of bytes received.
+  template <typename MutableBufferSequence>
+  std::size_t receive(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return do_receive(impl,
+        buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::first(buffers), flags, ec);
+  }
+
+  // Wait until data can be received without blocking.
+  std::size_t receive(base_implementation_type&, const null_buffers&,
+      socket_base::message_flags, asio::error_code& ec)
+  {
+    ec = asio::error::operation_not_supported;
+    return 0;
+  }
+
+  // Start an asynchronous receive. The buffer for the data being received
+  // must be valid for the lifetime of the asynchronous operation.
+  template <typename MutableBufferSequence, typename Handler>
+  void async_receive(base_implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, Handler& handler)
+  {
+    bool is_continuation =
+      asio_handler_cont_helpers::is_continuation(handler);
+
+    // Allocate and construct an operation to wrap the handler.
+    typedef winrt_socket_recv_op<MutableBufferSequence, Handler> op;
+    typename op::ptr p = { asio::detail::addressof(handler),
+      op::ptr::allocate(handler), 0 };
+    p.p = new (p.v) op(buffers, handler);
+
+    ASIO_HANDLER_CREATION((io_context_.context(),
+          *p.p, "socket", &impl, 0, "async_receive"));
+
+    start_receive_op(impl,
+        buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::first(buffers),
+        flags, p.p, is_continuation);
+    p.v = p.p = 0;
+  }
+
+  // Wait until data can be received without blocking.
+  template <typename Handler>
+  void async_receive(base_implementation_type&, const null_buffers&,
+      socket_base::message_flags, Handler& handler)
+  {
+    asio::error_code ec = asio::error::operation_not_supported;
+    const std::size_t bytes_transferred = 0;
+    io_context_.get_io_context().post(
+        detail::bind_handler(handler, ec, bytes_transferred));
+  }
+
+protected:
+  // Helper function to obtain endpoints associated with the connection.
+  ASIO_DECL std::size_t do_get_endpoint(
+      const base_implementation_type& impl, bool local,
+      void* addr, std::size_t addr_len, asio::error_code& ec) const;
+
+  // Helper function to set a socket option.
+  ASIO_DECL asio::error_code do_set_option(
+      base_implementation_type& impl,
+      int level, int optname, const void* optval,
+      std::size_t optlen, asio::error_code& ec);
+
+  // Helper function to get a socket option.
+  ASIO_DECL void do_get_option(
+      const base_implementation_type& impl,
+      int level, int optname, void* optval,
+      std::size_t* optlen, asio::error_code& ec) const;
+
+  // Helper function to perform a synchronous connect.
+  ASIO_DECL asio::error_code do_connect(
+      base_implementation_type& impl,
+      const void* addr, asio::error_code& ec);
+
+  // Helper function to start an asynchronous connect.
+  ASIO_DECL void start_connect_op(
+      base_implementation_type& impl, const void* addr,
+      winrt_async_op<void>* op, bool is_continuation);
+
+  // Helper function to perform a synchronous send.
+  ASIO_DECL std::size_t do_send(
+      base_implementation_type& impl, const asio::const_buffer& data,
+      socket_base::message_flags flags, asio::error_code& ec);
+
+  // Helper function to start an asynchronous send.
+  ASIO_DECL void start_send_op(base_implementation_type& impl,
+      const asio::const_buffer& data, socket_base::message_flags flags,
+      winrt_async_op<unsigned int>* op, bool is_continuation);
+
+  // Helper function to perform a synchronous receive.
+  ASIO_DECL std::size_t do_receive(
+      base_implementation_type& impl, const asio::mutable_buffer& data,
+      socket_base::message_flags flags, asio::error_code& ec);
+
+  // Helper function to start an asynchronous receive.
+  ASIO_DECL void start_receive_op(base_implementation_type& impl,
+      const asio::mutable_buffer& data, socket_base::message_flags flags,
+      winrt_async_op<Windows::Storage::Streams::IBuffer^>* op,
+      bool is_continuation);
+
+  // The io_context implementation used for delivering completions.
+  io_context_impl& io_context_;
+
+  // The manager that keeps track of outstanding operations.
+  winrt_async_manager& async_manager_;
+
+  // Mutex to protect access to the linked list of implementations. 
+  asio::detail::mutex mutex_;
+
+  // The head of a linked list of all implementations.
+  base_implementation_type* impl_list_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/winrt_ssocket_service_base.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_SSOCKET_SERVICE_BASE_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_timer_scheduler.hpp b/subprojects/asio/include/asio/detail/winrt_timer_scheduler.hpp
new file mode 100644
index 000000000..5dec7c0b6
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_timer_scheduler.hpp
@@ -0,0 +1,137 @@
+//
+// detail/winrt_timer_scheduler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_TIMER_SCHEDULER_HPP
+#define ASIO_DETAIL_WINRT_TIMER_SCHEDULER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include <cstddef>
+#include "asio/detail/event.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/op_queue.hpp"
+#include "asio/detail/thread.hpp"
+#include "asio/detail/timer_queue_base.hpp"
+#include "asio/detail/timer_queue_set.hpp"
+#include "asio/detail/wait_op.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+# include "asio/detail/thread.hpp"
+#endif // defined(ASIO_HAS_IOCP)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class winrt_timer_scheduler
+  : public asio::detail::service_base<winrt_timer_scheduler>
+{
+public:
+  // Constructor.
+  ASIO_DECL winrt_timer_scheduler(asio::io_context& io_context);
+
+  // Destructor.
+  ASIO_DECL ~winrt_timer_scheduler();
+
+  // Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL void shutdown();
+
+  // Recreate internal descriptors following a fork.
+  ASIO_DECL void notify_fork(
+      asio::io_context::fork_event fork_ev);
+
+  // Initialise the task. No effect as this class uses its own thread.
+  ASIO_DECL void init_task();
+
+  // Add a new timer queue to the reactor.
+  template <typename Time_Traits>
+  void add_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Remove a timer queue from the reactor.
+  template <typename Time_Traits>
+  void remove_timer_queue(timer_queue<Time_Traits>& queue);
+
+  // Schedule a new operation in the given timer queue to expire at the
+  // specified absolute time.
+  template <typename Time_Traits>
+  void schedule_timer(timer_queue<Time_Traits>& queue,
+      const typename Time_Traits::time_type& time,
+      typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
+
+  // Cancel the timer operations associated with the given token. Returns the
+  // number of operations that have been posted or dispatched.
+  template <typename Time_Traits>
+  std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& timer,
+      std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
+
+  // Move the timer operations associated with the given timer.
+  template <typename Time_Traits>
+  void move_timer(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data& to,
+      typename timer_queue<Time_Traits>::per_timer_data& from);
+
+private:
+  // Run the select loop in the thread.
+  ASIO_DECL void run_thread();
+
+  // Entry point for the select loop thread.
+  ASIO_DECL static void call_run_thread(winrt_timer_scheduler* reactor);
+
+  // Helper function to add a new timer queue.
+  ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
+
+  // Helper function to remove a timer queue.
+  ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
+
+  // The io_context implementation used to post completions.
+  io_context_impl& io_context_;
+
+  // Mutex used to protect internal variables.
+  asio::detail::mutex mutex_;
+
+  // Event used to wake up background thread.
+  asio::detail::event event_;
+
+  // The timer queues.
+  timer_queue_set timer_queues_;
+
+  // The background thread that is waiting for timers to expire.
+  asio::detail::thread* thread_;
+
+  // Does the background thread need to stop.
+  bool stop_thread_;
+
+  // Whether the service has been shut down.
+  bool shutdown_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/detail/impl/winrt_timer_scheduler.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/winrt_timer_scheduler.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_TIMER_SCHEDULER_HPP
diff --git a/subprojects/asio/include/asio/detail/winrt_utils.hpp b/subprojects/asio/include/asio/detail/winrt_utils.hpp
new file mode 100644
index 000000000..22a248958
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winrt_utils.hpp
@@ -0,0 +1,106 @@
+//
+// detail/winrt_utils.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINRT_UTILS_HPP
+#define ASIO_DETAIL_WINRT_UTILS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+
+#include <codecvt>
+#include <cstdlib>
+#include <future>
+#include <locale>
+#include <robuffer.h>
+#include <windows.storage.streams.h>
+#include <wrl/implements.h>
+#include "asio/buffer.hpp"
+#include "asio/error_code.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/socket_ops.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+namespace winrt_utils {
+
+inline Platform::String^ string(const char* from)
+{
+  std::wstring tmp(from, from + std::strlen(from));
+  return ref new Platform::String(tmp.c_str());
+}
+
+inline Platform::String^ string(const std::string& from)
+{
+  std::wstring tmp(from.begin(), from.end());
+  return ref new Platform::String(tmp.c_str());
+}
+
+inline std::string string(Platform::String^ from)
+{
+  std::wstring_convert<std::codecvt_utf8<wchar_t>> converter;
+  return converter.to_bytes(from->Data());
+}
+
+inline Platform::String^ string(unsigned short from)
+{
+  return string(std::to_string(from));
+}
+
+template <typename T>
+inline Platform::String^ string(const T& from)
+{
+  return string(from.to_string());
+}
+
+inline int integer(Platform::String^ from)
+{
+  return _wtoi(from->Data());
+}
+
+template <typename T>
+inline Windows::Networking::HostName^ host_name(const T& from)
+{
+  return ref new Windows::Networking::HostName((string)(from));
+}
+
+template <typename ConstBufferSequence>
+inline Windows::Storage::Streams::IBuffer^ buffer_dup(
+    const ConstBufferSequence& buffers)
+{
+  using Microsoft::WRL::ComPtr;
+  using asio::buffer_size;
+  std::size_t size = buffer_size(buffers);
+  auto b = ref new Windows::Storage::Streams::Buffer(size);
+  ComPtr<IInspectable> insp = reinterpret_cast<IInspectable*>(b);
+  ComPtr<Windows::Storage::Streams::IBufferByteAccess> bacc;
+  insp.As(&bacc);
+  byte* bytes = nullptr;
+  bacc->Buffer(&bytes);
+  asio::buffer_copy(asio::buffer(bytes, size), buffers);
+  b->Length = size;
+  return b;
+}
+
+} // namespace winrt_utils
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#endif // ASIO_DETAIL_WINRT_UTILS_HPP
diff --git a/subprojects/asio/include/asio/detail/winsock_init.hpp b/subprojects/asio/include/asio/detail/winsock_init.hpp
new file mode 100644
index 000000000..9094363ab
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/winsock_init.hpp
@@ -0,0 +1,128 @@
+//
+// detail/winsock_init.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WINSOCK_INIT_HPP
+#define ASIO_DETAIL_WINSOCK_INIT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class winsock_init_base
+{
+protected:
+  // Structure to track result of initialisation and number of uses. POD is used
+  // to ensure that the values are zero-initialised prior to any code being run.
+  struct data
+  {
+    long init_count_;
+    long result_;
+  };
+
+  ASIO_DECL static void startup(data& d,
+      unsigned char major, unsigned char minor);
+
+  ASIO_DECL static void manual_startup(data& d);
+
+  ASIO_DECL static void cleanup(data& d);
+
+  ASIO_DECL static void manual_cleanup(data& d);
+
+  ASIO_DECL static void throw_on_error(data& d);
+};
+
+template <int Major = 2, int Minor = 0>
+class winsock_init : private winsock_init_base
+{
+public:
+  winsock_init(bool allow_throw = true)
+  {
+    startup(data_, Major, Minor);
+    if (allow_throw)
+      throw_on_error(data_);
+  }
+
+  winsock_init(const winsock_init&)
+  {
+    startup(data_, Major, Minor);
+    throw_on_error(data_);
+  }
+
+  ~winsock_init()
+  {
+    cleanup(data_);
+  }
+
+  // This class may be used to indicate that user code will manage Winsock
+  // initialisation and cleanup. This may be required in the case of a DLL, for
+  // example, where it is not safe to initialise Winsock from global object
+  // constructors.
+  //
+  // To prevent asio from initialising Winsock, the object must be constructed
+  // before any Asio's own global objects. With MSVC, this may be accomplished
+  // by adding the following code to the DLL:
+  //
+  //   #pragma warning(push)
+  //   #pragma warning(disable:4073)
+  //   #pragma init_seg(lib)
+  //   asio::detail::winsock_init<>::manual manual_winsock_init;
+  //   #pragma warning(pop)
+  class manual
+  {
+  public:
+    manual()
+    {
+      manual_startup(data_);
+    }
+
+    manual(const manual&)
+    {
+      manual_startup(data_);
+    }
+
+    ~manual()
+    {
+      manual_cleanup(data_);
+    }
+  };
+
+private:
+  friend class manual;
+  static data data_;
+};
+
+template <int Major, int Minor>
+winsock_init_base::data winsock_init<Major, Minor>::data_;
+
+// Static variable to ensure that winsock is initialised before main, and
+// therefore before any other threads can get started.
+static const winsock_init<>& winsock_init_instance = winsock_init<>(false);
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/detail/impl/winsock_init.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+
+#endif // ASIO_DETAIL_WINSOCK_INIT_HPP
diff --git a/subprojects/asio/include/asio/detail/work_dispatcher.hpp b/subprojects/asio/include/asio/detail/work_dispatcher.hpp
new file mode 100644
index 000000000..7abce497b
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/work_dispatcher.hpp
@@ -0,0 +1,72 @@
+//
+// detail/work_dispatcher.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WORK_DISPATCHER_HPP
+#define ASIO_DETAIL_WORK_DISPATCHER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/executor_work_guard.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Handler>
+class work_dispatcher
+{
+public:
+  work_dispatcher(Handler& handler)
+    : work_((get_associated_executor)(handler)),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  work_dispatcher(const work_dispatcher& other)
+    : work_(other.work_),
+      handler_(other.handler_)
+  {
+  }
+
+  work_dispatcher(work_dispatcher&& other)
+    : work_(ASIO_MOVE_CAST(executor_work_guard<
+        typename associated_executor<Handler>::type>)(other.work_)),
+      handler_(ASIO_MOVE_CAST(Handler)(other.handler_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    typename associated_allocator<Handler>::type alloc(
+        (get_associated_allocator)(handler_));
+    work_.get_executor().dispatch(
+        ASIO_MOVE_CAST(Handler)(handler_), alloc);
+    work_.reset();
+  }
+
+private:
+  executor_work_guard<typename associated_executor<Handler>::type> work_;
+  Handler handler_;
+};
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WORK_DISPATCHER_HPP
diff --git a/subprojects/asio/include/asio/detail/wrapped_handler.hpp b/subprojects/asio/include/asio/detail/wrapped_handler.hpp
new file mode 100644
index 000000000..751f0ea83
--- /dev/null
+++ b/subprojects/asio/include/asio/detail/wrapped_handler.hpp
@@ -0,0 +1,291 @@
+//
+// detail/wrapped_handler.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WRAPPED_HANDLER_HPP
+#define ASIO_DETAIL_WRAPPED_HANDLER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct is_continuation_delegated
+{
+  template <typename Dispatcher, typename Handler>
+  bool operator()(Dispatcher&, Handler& handler) const
+  {
+    return asio_handler_cont_helpers::is_continuation(handler);
+  }
+};
+
+struct is_continuation_if_running
+{
+  template <typename Dispatcher, typename Handler>
+  bool operator()(Dispatcher& dispatcher, Handler&) const
+  {
+    return dispatcher.running_in_this_thread();
+  }
+};
+
+template <typename Dispatcher, typename Handler,
+    typename IsContinuation = is_continuation_delegated>
+class wrapped_handler
+{
+public:
+  typedef void result_type;
+
+  wrapped_handler(Dispatcher dispatcher, Handler& handler)
+    : dispatcher_(dispatcher),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  wrapped_handler(const wrapped_handler& other)
+    : dispatcher_(other.dispatcher_),
+      handler_(other.handler_)
+  {
+  }
+
+  wrapped_handler(wrapped_handler&& other)
+    : dispatcher_(other.dispatcher_),
+      handler_(ASIO_MOVE_CAST(Handler)(other.handler_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    dispatcher_.dispatch(ASIO_MOVE_CAST(Handler)(handler_));
+  }
+
+  void operator()() const
+  {
+    dispatcher_.dispatch(handler_);
+  }
+
+  template <typename Arg1>
+  void operator()(const Arg1& arg1)
+  {
+    dispatcher_.dispatch(detail::bind_handler(handler_, arg1));
+  }
+
+  template <typename Arg1>
+  void operator()(const Arg1& arg1) const
+  {
+    dispatcher_.dispatch(detail::bind_handler(handler_, arg1));
+  }
+
+  template <typename Arg1, typename Arg2>
+  void operator()(const Arg1& arg1, const Arg2& arg2)
+  {
+    dispatcher_.dispatch(detail::bind_handler(handler_, arg1, arg2));
+  }
+
+  template <typename Arg1, typename Arg2>
+  void operator()(const Arg1& arg1, const Arg2& arg2) const
+  {
+    dispatcher_.dispatch(detail::bind_handler(handler_, arg1, arg2));
+  }
+
+  template <typename Arg1, typename Arg2, typename Arg3>
+  void operator()(const Arg1& arg1, const Arg2& arg2, const Arg3& arg3)
+  {
+    dispatcher_.dispatch(detail::bind_handler(handler_, arg1, arg2, arg3));
+  }
+
+  template <typename Arg1, typename Arg2, typename Arg3>
+  void operator()(const Arg1& arg1, const Arg2& arg2, const Arg3& arg3) const
+  {
+    dispatcher_.dispatch(detail::bind_handler(handler_, arg1, arg2, arg3));
+  }
+
+  template <typename Arg1, typename Arg2, typename Arg3, typename Arg4>
+  void operator()(const Arg1& arg1, const Arg2& arg2, const Arg3& arg3,
+      const Arg4& arg4)
+  {
+    dispatcher_.dispatch(
+        detail::bind_handler(handler_, arg1, arg2, arg3, arg4));
+  }
+
+  template <typename Arg1, typename Arg2, typename Arg3, typename Arg4>
+  void operator()(const Arg1& arg1, const Arg2& arg2, const Arg3& arg3,
+      const Arg4& arg4) const
+  {
+    dispatcher_.dispatch(
+        detail::bind_handler(handler_, arg1, arg2, arg3, arg4));
+  }
+
+  template <typename Arg1, typename Arg2, typename Arg3, typename Arg4,
+      typename Arg5>
+  void operator()(const Arg1& arg1, const Arg2& arg2, const Arg3& arg3,
+      const Arg4& arg4, const Arg5& arg5)
+  {
+    dispatcher_.dispatch(
+        detail::bind_handler(handler_, arg1, arg2, arg3, arg4, arg5));
+  }
+
+  template <typename Arg1, typename Arg2, typename Arg3, typename Arg4,
+      typename Arg5>
+  void operator()(const Arg1& arg1, const Arg2& arg2, const Arg3& arg3,
+      const Arg4& arg4, const Arg5& arg5) const
+  {
+    dispatcher_.dispatch(
+        detail::bind_handler(handler_, arg1, arg2, arg3, arg4, arg5));
+  }
+
+//private:
+  Dispatcher dispatcher_;
+  Handler handler_;
+};
+
+template <typename Handler, typename Context>
+class rewrapped_handler
+{
+public:
+  explicit rewrapped_handler(Handler& handler, const Context& context)
+    : context_(context),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+  }
+
+  explicit rewrapped_handler(const Handler& handler, const Context& context)
+    : context_(context),
+      handler_(handler)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  rewrapped_handler(const rewrapped_handler& other)
+    : context_(other.context_),
+      handler_(other.handler_)
+  {
+  }
+
+  rewrapped_handler(rewrapped_handler&& other)
+    : context_(ASIO_MOVE_CAST(Context)(other.context_)),
+      handler_(ASIO_MOVE_CAST(Handler)(other.handler_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()()
+  {
+    handler_();
+  }
+
+  void operator()() const
+  {
+    handler_();
+  }
+
+//private:
+  Context context_;
+  Handler handler_;
+};
+
+template <typename Dispatcher, typename Handler, typename IsContinuation>
+inline void* asio_handler_allocate(std::size_t size,
+    wrapped_handler<Dispatcher, Handler, IsContinuation>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Dispatcher, typename Handler, typename IsContinuation>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    wrapped_handler<Dispatcher, Handler, IsContinuation>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Dispatcher, typename Handler, typename IsContinuation>
+inline bool asio_handler_is_continuation(
+    wrapped_handler<Dispatcher, Handler, IsContinuation>* this_handler)
+{
+  return IsContinuation()(this_handler->dispatcher_, this_handler->handler_);
+}
+
+template <typename Function, typename Dispatcher,
+    typename Handler, typename IsContinuation>
+inline void asio_handler_invoke(Function& function,
+    wrapped_handler<Dispatcher, Handler, IsContinuation>* this_handler)
+{
+  this_handler->dispatcher_.dispatch(
+      rewrapped_handler<Function, Handler>(
+        function, this_handler->handler_));
+}
+
+template <typename Function, typename Dispatcher,
+    typename Handler, typename IsContinuation>
+inline void asio_handler_invoke(const Function& function,
+    wrapped_handler<Dispatcher, Handler, IsContinuation>* this_handler)
+{
+  this_handler->dispatcher_.dispatch(
+      rewrapped_handler<Function, Handler>(
+        function, this_handler->handler_));
+}
+
+template <typename Handler, typename Context>
+inline void* asio_handler_allocate(std::size_t size,
+    rewrapped_handler<Handler, Context>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->context_);
+}
+
+template <typename Handler, typename Context>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    rewrapped_handler<Handler, Context>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->context_);
+}
+
+template <typename Dispatcher, typename Context>
+inline bool asio_handler_is_continuation(
+    rewrapped_handler<Dispatcher, Context>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+      this_handler->context_);
+}
+
+template <typename Function, typename Handler, typename Context>
+inline void asio_handler_invoke(Function& function,
+    rewrapped_handler<Handler, Context>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->context_);
+}
+
+template <typename Function, typename Handler, typename Context>
+inline void asio_handler_invoke(const Function& function,
+    rewrapped_handler<Handler, Context>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->context_);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WRAPPED_HANDLER_HPP
diff --git a/subprojects/asio/include/asio/dispatch.hpp b/subprojects/asio/include/asio/dispatch.hpp
new file mode 100644
index 000000000..b8dfd6910
--- /dev/null
+++ b/subprojects/asio/include/asio/dispatch.hpp
@@ -0,0 +1,108 @@
+//
+// dispatch.hpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DISPATCH_HPP
+#define ASIO_DISPATCH_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/is_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Submits a completion token or function object for execution.
+/**
+ * This function submits an object for execution using the object's associated
+ * executor. The function object is queued for execution, and is never called
+ * from the current thread prior to returning from <tt>dispatch()</tt>.
+ *
+ * This function has the following effects:
+ *
+ * @li Constructs a function object handler of type @c Handler, initialized
+ * with <tt>handler(forward<CompletionToken>(token))</tt>.
+ *
+ * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
+ * initializing the object as <tt>result(handler)</tt>.
+ *
+ * @li Obtains the handler's associated executor object @c ex by performing
+ * <tt>get_associated_executor(handler)</tt>.
+ *
+ * @li Obtains the handler's associated allocator object @c alloc by performing
+ * <tt>get_associated_allocator(handler)</tt>.
+ *
+ * @li Performs <tt>ex.dispatch(std::move(handler), alloc)</tt>.
+ *
+ * @li Returns <tt>result.get()</tt>.
+ */
+template <typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) dispatch(
+    ASIO_MOVE_ARG(CompletionToken) token);
+
+/// Submits a completion token or function object for execution.
+/**
+ * This function submits an object for execution using the specified executor.
+ * The function object is queued for execution, and is never called from the
+ * current thread prior to returning from <tt>dispatch()</tt>.
+ *
+ * This function has the following effects:
+ *
+ * @li Constructs a function object handler of type @c Handler, initialized
+ * with <tt>handler(forward<CompletionToken>(token))</tt>.
+ *
+ * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
+ * initializing the object as <tt>result(handler)</tt>.
+ *
+ * @li Obtains the handler's associated executor object @c ex1 by performing
+ * <tt>get_associated_executor(handler)</tt>.
+ *
+ * @li Creates a work object @c w by performing <tt>make_work(ex1)</tt>.
+ *
+ * @li Obtains the handler's associated allocator object @c alloc by performing
+ * <tt>get_associated_allocator(handler)</tt>.
+ *
+ * @li Constructs a function object @c f with a function call operator that
+ * performs <tt>ex1.dispatch(std::move(handler), alloc)</tt> followed by
+ * <tt>w.reset()</tt>.
+ *
+ * @li Performs <tt>Executor(ex).dispatch(std::move(f), alloc)</tt>.
+ *
+ * @li Returns <tt>result.get()</tt>.
+ */
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) dispatch(
+    const Executor& ex, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_executor<Executor>::value>::type* = 0);
+
+/// Submits a completion token or function object for execution.
+/**
+ * @returns <tt>dispatch(ctx.get_executor(),
+ * forward<CompletionToken>(token))</tt>.
+ */
+template <typename ExecutionContext, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) dispatch(
+    ExecutionContext& ctx, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type* = 0);
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/dispatch.hpp"
+
+#endif // ASIO_DISPATCH_HPP
diff --git a/subprojects/asio/include/asio/error.hpp b/subprojects/asio/include/asio/error.hpp
new file mode 100644
index 000000000..2be9bdeed
--- /dev/null
+++ b/subprojects/asio/include/asio/error.hpp
@@ -0,0 +1,356 @@
+//
+// error.hpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_ERROR_HPP
+#define ASIO_ERROR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/error_code.hpp"
+#include "asio/system_error.hpp"
+#if defined(ASIO_WINDOWS) \
+  || defined(__CYGWIN__) \
+  || defined(ASIO_WINDOWS_RUNTIME)
+# include <winerror.h>
+#else
+# include <cerrno>
+# include <netdb.h>
+#endif
+
+#if defined(GENERATING_DOCUMENTATION)
+/// INTERNAL ONLY.
+# define ASIO_NATIVE_ERROR(e) implementation_defined
+/// INTERNAL ONLY.
+# define ASIO_SOCKET_ERROR(e) implementation_defined
+/// INTERNAL ONLY.
+# define ASIO_NETDB_ERROR(e) implementation_defined
+/// INTERNAL ONLY.
+# define ASIO_GETADDRINFO_ERROR(e) implementation_defined
+/// INTERNAL ONLY.
+# define ASIO_WIN_OR_POSIX(e_win, e_posix) implementation_defined
+#elif defined(ASIO_WINDOWS_RUNTIME)
+# define ASIO_NATIVE_ERROR(e) __HRESULT_FROM_WIN32(e)
+# define ASIO_SOCKET_ERROR(e) __HRESULT_FROM_WIN32(WSA ## e)
+# define ASIO_NETDB_ERROR(e) __HRESULT_FROM_WIN32(WSA ## e)
+# define ASIO_GETADDRINFO_ERROR(e) __HRESULT_FROM_WIN32(WSA ## e)
+# define ASIO_WIN_OR_POSIX(e_win, e_posix) e_win
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# define ASIO_NATIVE_ERROR(e) e
+# define ASIO_SOCKET_ERROR(e) WSA ## e
+# define ASIO_NETDB_ERROR(e) WSA ## e
+# define ASIO_GETADDRINFO_ERROR(e) WSA ## e
+# define ASIO_WIN_OR_POSIX(e_win, e_posix) e_win
+#else
+# define ASIO_NATIVE_ERROR(e) e
+# define ASIO_SOCKET_ERROR(e) e
+# define ASIO_NETDB_ERROR(e) e
+# define ASIO_GETADDRINFO_ERROR(e) e
+# define ASIO_WIN_OR_POSIX(e_win, e_posix) e_posix
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace error {
+
+enum basic_errors
+{
+  /// Permission denied.
+  access_denied = ASIO_SOCKET_ERROR(EACCES),
+
+  /// Address family not supported by protocol.
+  address_family_not_supported = ASIO_SOCKET_ERROR(EAFNOSUPPORT),
+
+  /// Address already in use.
+  address_in_use = ASIO_SOCKET_ERROR(EADDRINUSE),
+
+  /// Transport endpoint is already connected.
+  already_connected = ASIO_SOCKET_ERROR(EISCONN),
+
+  /// Operation already in progress.
+  already_started = ASIO_SOCKET_ERROR(EALREADY),
+
+  /// Broken pipe.
+  broken_pipe = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(ERROR_BROKEN_PIPE),
+      ASIO_NATIVE_ERROR(EPIPE)),
+
+  /// A connection has been aborted.
+  connection_aborted = ASIO_SOCKET_ERROR(ECONNABORTED),
+
+  /// Connection refused.
+  connection_refused = ASIO_SOCKET_ERROR(ECONNREFUSED),
+
+  /// Connection reset by peer.
+  connection_reset = ASIO_SOCKET_ERROR(ECONNRESET),
+
+  /// Bad file descriptor.
+  bad_descriptor = ASIO_SOCKET_ERROR(EBADF),
+
+  /// Bad address.
+  fault = ASIO_SOCKET_ERROR(EFAULT),
+
+  /// No route to host.
+  host_unreachable = ASIO_SOCKET_ERROR(EHOSTUNREACH),
+
+  /// Operation now in progress.
+  in_progress = ASIO_SOCKET_ERROR(EINPROGRESS),
+
+  /// Interrupted system call.
+  interrupted = ASIO_SOCKET_ERROR(EINTR),
+
+  /// Invalid argument.
+  invalid_argument = ASIO_SOCKET_ERROR(EINVAL),
+
+  /// Message too long.
+  message_size = ASIO_SOCKET_ERROR(EMSGSIZE),
+
+  /// The name was too long.
+  name_too_long = ASIO_SOCKET_ERROR(ENAMETOOLONG),
+
+  /// Network is down.
+  network_down = ASIO_SOCKET_ERROR(ENETDOWN),
+
+  /// Network dropped connection on reset.
+  network_reset = ASIO_SOCKET_ERROR(ENETRESET),
+
+  /// Network is unreachable.
+  network_unreachable = ASIO_SOCKET_ERROR(ENETUNREACH),
+
+  /// Too many open files.
+  no_descriptors = ASIO_SOCKET_ERROR(EMFILE),
+
+  /// No buffer space available.
+  no_buffer_space = ASIO_SOCKET_ERROR(ENOBUFS),
+
+  /// Cannot allocate memory.
+  no_memory = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(ERROR_OUTOFMEMORY),
+      ASIO_NATIVE_ERROR(ENOMEM)),
+
+  /// Operation not permitted.
+  no_permission = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(ERROR_ACCESS_DENIED),
+      ASIO_NATIVE_ERROR(EPERM)),
+
+  /// Protocol not available.
+  no_protocol_option = ASIO_SOCKET_ERROR(ENOPROTOOPT),
+
+  /// No such device.
+  no_such_device = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(ERROR_BAD_UNIT),
+      ASIO_NATIVE_ERROR(ENODEV)),
+
+  /// Transport endpoint is not connected.
+  not_connected = ASIO_SOCKET_ERROR(ENOTCONN),
+
+  /// Socket operation on non-socket.
+  not_socket = ASIO_SOCKET_ERROR(ENOTSOCK),
+
+  /// Operation cancelled.
+  operation_aborted = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(ERROR_OPERATION_ABORTED),
+      ASIO_NATIVE_ERROR(ECANCELED)),
+
+  /// Operation not supported.
+  operation_not_supported = ASIO_SOCKET_ERROR(EOPNOTSUPP),
+
+  /// Cannot send after transport endpoint shutdown.
+  shut_down = ASIO_SOCKET_ERROR(ESHUTDOWN),
+
+  /// Connection timed out.
+  timed_out = ASIO_SOCKET_ERROR(ETIMEDOUT),
+
+  /// Resource temporarily unavailable.
+  try_again = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(ERROR_RETRY),
+      ASIO_NATIVE_ERROR(EAGAIN)),
+
+  /// The socket is marked non-blocking and the requested operation would block.
+  would_block = ASIO_SOCKET_ERROR(EWOULDBLOCK)
+};
+
+enum netdb_errors
+{
+  /// Host not found (authoritative).
+  host_not_found = ASIO_NETDB_ERROR(HOST_NOT_FOUND),
+
+  /// Host not found (non-authoritative).
+  host_not_found_try_again = ASIO_NETDB_ERROR(TRY_AGAIN),
+
+  /// The query is valid but does not have associated address data.
+  no_data = ASIO_NETDB_ERROR(NO_DATA),
+
+  /// A non-recoverable error occurred.
+  no_recovery = ASIO_NETDB_ERROR(NO_RECOVERY)
+};
+
+enum addrinfo_errors
+{
+  /// The service is not supported for the given socket type.
+  service_not_found = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(WSATYPE_NOT_FOUND),
+      ASIO_GETADDRINFO_ERROR(EAI_SERVICE)),
+
+  /// The socket type is not supported.
+  socket_type_not_supported = ASIO_WIN_OR_POSIX(
+      ASIO_NATIVE_ERROR(WSAESOCKTNOSUPPORT),
+      ASIO_GETADDRINFO_ERROR(EAI_SOCKTYPE))
+};
+
+enum misc_errors
+{
+  /// Already open.
+  already_open = 1,
+
+  /// End of file or stream.
+  eof,
+
+  /// Element not found.
+  not_found,
+
+  /// The descriptor cannot fit into the select system call's fd_set.
+  fd_set_failure
+};
+
+inline const asio::error_category& get_system_category()
+{
+  return asio::system_category();
+}
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+extern ASIO_DECL
+const asio::error_category& get_netdb_category();
+
+extern ASIO_DECL
+const asio::error_category& get_addrinfo_category();
+
+#else // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+inline const asio::error_category& get_netdb_category()
+{
+  return get_system_category();
+}
+
+inline const asio::error_category& get_addrinfo_category()
+{
+  return get_system_category();
+}
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+extern ASIO_DECL
+const asio::error_category& get_misc_category();
+
+static const asio::error_category&
+  system_category ASIO_UNUSED_VARIABLE
+  = asio::error::get_system_category();
+static const asio::error_category&
+  netdb_category ASIO_UNUSED_VARIABLE
+  = asio::error::get_netdb_category();
+static const asio::error_category&
+  addrinfo_category ASIO_UNUSED_VARIABLE
+  = asio::error::get_addrinfo_category();
+static const asio::error_category&
+  misc_category ASIO_UNUSED_VARIABLE
+  = asio::error::get_misc_category();
+
+} // namespace error
+} // namespace asio
+
+#if defined(ASIO_HAS_STD_SYSTEM_ERROR)
+namespace std {
+
+template<> struct is_error_code_enum<asio::error::basic_errors>
+{
+  static const bool value = true;
+};
+
+template<> struct is_error_code_enum<asio::error::netdb_errors>
+{
+  static const bool value = true;
+};
+
+template<> struct is_error_code_enum<asio::error::addrinfo_errors>
+{
+  static const bool value = true;
+};
+
+template<> struct is_error_code_enum<asio::error::misc_errors>
+{
+  static const bool value = true;
+};
+
+} // namespace std
+#endif // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+namespace asio {
+namespace error {
+
+inline asio::error_code make_error_code(basic_errors e)
+{
+  return asio::error_code(
+      static_cast<int>(e), get_system_category());
+}
+
+inline asio::error_code make_error_code(netdb_errors e)
+{
+  return asio::error_code(
+      static_cast<int>(e), get_netdb_category());
+}
+
+inline asio::error_code make_error_code(addrinfo_errors e)
+{
+  return asio::error_code(
+      static_cast<int>(e), get_addrinfo_category());
+}
+
+inline asio::error_code make_error_code(misc_errors e)
+{
+  return asio::error_code(
+      static_cast<int>(e), get_misc_category());
+}
+
+} // namespace error
+namespace stream_errc {
+  // Simulates the proposed stream_errc scoped enum.
+  using error::eof;
+  using error::not_found;
+} // namespace stream_errc
+namespace socket_errc {
+  // Simulates the proposed socket_errc scoped enum.
+  using error::already_open;
+  using error::not_found;
+} // namespace socket_errc
+namespace resolver_errc {
+  // Simulates the proposed resolver_errc scoped enum.
+  using error::host_not_found;
+  const error::netdb_errors try_again = error::host_not_found_try_again;
+  using error::service_not_found;
+} // namespace resolver_errc
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#undef ASIO_NATIVE_ERROR
+#undef ASIO_SOCKET_ERROR
+#undef ASIO_NETDB_ERROR
+#undef ASIO_GETADDRINFO_ERROR
+#undef ASIO_WIN_OR_POSIX
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/error.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_ERROR_HPP
diff --git a/subprojects/asio/include/asio/error_code.hpp b/subprojects/asio/include/asio/error_code.hpp
new file mode 100644
index 000000000..7c239e2fa
--- /dev/null
+++ b/subprojects/asio/include/asio/error_code.hpp
@@ -0,0 +1,202 @@
+//
+// error_code.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_ERROR_CODE_HPP
+#define ASIO_ERROR_CODE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_SYSTEM_ERROR)
+# include <system_error>
+#else // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+# include <string>
+# include "asio/detail/noncopyable.hpp"
+# if !defined(ASIO_NO_IOSTREAM)
+#  include <iosfwd>
+# endif // !defined(ASIO_NO_IOSTREAM)
+#endif // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+typedef std::error_category error_category;
+
+#else // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+/// Base class for all error categories.
+class error_category : private noncopyable
+{
+public:
+  /// Destructor.
+  virtual ~error_category()
+  {
+  }
+
+  /// Returns a string naming the error gategory.
+  virtual const char* name() const = 0;
+
+  /// Returns a string describing the error denoted by @c value.
+  virtual std::string message(int value) const = 0;
+
+  /// Equality operator to compare two error categories.
+  bool operator==(const error_category& rhs) const
+  {
+    return this == &rhs;
+  }
+
+  /// Inequality operator to compare two error categories.
+  bool operator!=(const error_category& rhs) const
+  {
+    return !(*this == rhs);
+  }
+};
+
+#endif // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+/// Returns the error category used for the system errors produced by asio.
+extern ASIO_DECL const error_category& system_category();
+
+#if defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+typedef std::error_code error_code;
+
+#else // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+/// Class to represent an error code value.
+class error_code
+{
+public:
+  /// Default constructor.
+  error_code()
+    : value_(0),
+      category_(&system_category())
+  {
+  }
+
+  /// Construct with specific error code and category.
+  error_code(int v, const error_category& c)
+    : value_(v),
+      category_(&c)
+  {
+  }
+
+  /// Construct from an error code enum.
+  template <typename ErrorEnum>
+  error_code(ErrorEnum e)
+  {
+    *this = make_error_code(e);
+  }
+
+  /// Clear the error value to the default.
+  void clear()
+  {
+    value_ = 0;
+    category_ = &system_category();
+  }
+
+  /// Assign a new error value.
+  void assign(int v, const error_category& c)
+  {
+    value_ = v;
+    category_ = &c;
+  }
+
+  /// Get the error value.
+  int value() const
+  {
+    return value_;
+  }
+
+  /// Get the error category.
+  const error_category& category() const
+  {
+    return *category_;
+  }
+
+  /// Get the message associated with the error.
+  std::string message() const
+  {
+    return category_->message(value_);
+  }
+
+  struct unspecified_bool_type_t
+  {
+  };
+
+  typedef void (*unspecified_bool_type)(unspecified_bool_type_t);
+
+  static void unspecified_bool_true(unspecified_bool_type_t) {}
+
+  /// Operator returns non-null if there is a non-success error code.
+  operator unspecified_bool_type() const
+  {
+    if (value_ == 0)
+      return 0;
+    else
+      return &error_code::unspecified_bool_true;
+  }
+
+  /// Operator to test if the error represents success.
+  bool operator!() const
+  {
+    return value_ == 0;
+  }
+
+  /// Equality operator to compare two error objects.
+  friend bool operator==(const error_code& e1, const error_code& e2)
+  {
+    return e1.value_ == e2.value_ && e1.category_ == e2.category_;
+  }
+
+  /// Inequality operator to compare two error objects.
+  friend bool operator!=(const error_code& e1, const error_code& e2)
+  {
+    return e1.value_ != e2.value_ || e1.category_ != e2.category_;
+  }
+
+private:
+  // The value associated with the error code.
+  int value_;
+
+  // The category associated with the error code.
+  const error_category* category_;
+};
+
+# if !defined(ASIO_NO_IOSTREAM)
+
+/// Output an error code.
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const error_code& ec)
+{
+  os << ec.category().name() << ':' << ec.value();
+  return os;
+}
+
+# endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/error_code.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_ERROR_CODE_HPP
diff --git a/subprojects/asio/include/asio/execution_context.hpp b/subprojects/asio/include/asio/execution_context.hpp
new file mode 100644
index 000000000..1476d19b5
--- /dev/null
+++ b/subprojects/asio/include/asio/execution_context.hpp
@@ -0,0 +1,411 @@
+//
+// execution_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXECUTION_CONTEXT_HPP
+#define ASIO_EXECUTION_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <stdexcept>
+#include <typeinfo>
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/variadic_templates.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class execution_context;
+class io_context;
+
+#if !defined(GENERATING_DOCUMENTATION)
+template <typename Service> Service& use_service(execution_context&);
+template <typename Service> Service& use_service(io_context&);
+template <typename Service> void add_service(execution_context&, Service*);
+template <typename Service> bool has_service(execution_context&);
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+namespace detail { class service_registry; }
+
+/// A context for function object execution.
+/**
+ * An execution context represents a place where function objects will be
+ * executed. An @c io_context is an example of an execution context.
+ *
+ * @par The execution_context class and services
+ *
+ * Class execution_context implements an extensible, type-safe, polymorphic set
+ * of services, indexed by service type.
+ *
+ * Services exist to manage the resources that are shared across an execution
+ * context. For example, timers may be implemented in terms of a single timer
+ * queue, and this queue would be stored in a service.
+ *
+ * Access to the services of an execution_context is via three function
+ * templates, use_service(), add_service() and has_service().
+ *
+ * In a call to @c use_service<Service>(), the type argument chooses a service,
+ * making available all members of the named type. If @c Service is not present
+ * in an execution_context, an object of type @c Service is created and added
+ * to the execution_context. A C++ program can check if an execution_context
+ * implements a particular service with the function template @c
+ * has_service<Service>().
+ *
+ * Service objects may be explicitly added to an execution_context using the
+ * function template @c add_service<Service>(). If the @c Service is already
+ * present, the service_already_exists exception is thrown. If the owner of the
+ * service is not the same object as the execution_context parameter, the
+ * invalid_service_owner exception is thrown.
+ *
+ * Once a service reference is obtained from an execution_context object by
+ * calling use_service(), that reference remains usable as long as the owning
+ * execution_context object exists.
+ *
+ * All service implementations have execution_context::service as a public base
+ * class. Custom services may be implemented by deriving from this class and
+ * then added to an execution_context using the facilities described above.
+ *
+ * @par The execution_context as a base class
+ *
+ * Class execution_context may be used only as a base class for concrete
+ * execution context types. The @c io_context is an example of such a derived
+ * type.
+ *
+ * On destruction, a class that is derived from execution_context must perform
+ * <tt>execution_context::shutdown()</tt> followed by
+ * <tt>execution_context::destroy()</tt>.
+ *
+ * This destruction sequence permits programs to simplify their resource
+ * management by using @c shared_ptr<>. Where an object's lifetime is tied to
+ * the lifetime of a connection (or some other sequence of asynchronous
+ * operations), a @c shared_ptr to the object would be bound into the handlers
+ * for all asynchronous operations associated with it. This works as follows:
+ *
+ * @li When a single connection ends, all associated asynchronous operations
+ * complete. The corresponding handler objects are destroyed, and all @c
+ * shared_ptr references to the objects are destroyed.
+ *
+ * @li To shut down the whole program, the io_context function stop() is called
+ * to terminate any run() calls as soon as possible. The io_context destructor
+ * calls @c shutdown() and @c destroy() to destroy all pending handlers,
+ * causing all @c shared_ptr references to all connection objects to be
+ * destroyed.
+ */
+class execution_context
+  : private noncopyable
+{
+public:
+  class id;
+  class service;
+
+protected:
+  /// Constructor.
+  ASIO_DECL execution_context();
+
+  /// Destructor.
+  ASIO_DECL ~execution_context();
+
+  /// Shuts down all services in the context.
+  /**
+   * This function is implemented as follows:
+   *
+   * @li For each service object @c svc in the execution_context set, in
+   * reverse order of the beginning of service object lifetime, performs @c
+   * svc->shutdown().
+   */
+  ASIO_DECL void shutdown();
+
+  /// Destroys all services in the context.
+  /**
+   * This function is implemented as follows:
+   *
+   * @li For each service object @c svc in the execution_context set, in
+   * reverse order * of the beginning of service object lifetime, performs
+   * <tt>delete static_cast<execution_context::service*>(svc)</tt>.
+   */
+  ASIO_DECL void destroy();
+
+public:
+  /// Fork-related event notifications.
+  enum fork_event
+  {
+    /// Notify the context that the process is about to fork.
+    fork_prepare,
+
+    /// Notify the context that the process has forked and is the parent.
+    fork_parent,
+
+    /// Notify the context that the process has forked and is the child.
+    fork_child
+  };
+
+  /// Notify the execution_context of a fork-related event.
+  /**
+   * This function is used to inform the execution_context that the process is
+   * about to fork, or has just forked. This allows the execution_context, and
+   * the services it contains, to perform any necessary housekeeping to ensure
+   * correct operation following a fork.
+   *
+   * This function must not be called while any other execution_context
+   * function, or any function associated with the execution_context's derived
+   * class, is being called in another thread. It is, however, safe to call
+   * this function from within a completion handler, provided no other thread
+   * is accessing the execution_context or its derived class.
+   *
+   * @param event A fork-related event.
+   *
+   * @throws asio::system_error Thrown on failure. If the notification
+   * fails the execution_context object should no longer be used and should be
+   * destroyed.
+   *
+   * @par Example
+   * The following code illustrates how to incorporate the notify_fork()
+   * function:
+   * @code my_execution_context.notify_fork(execution_context::fork_prepare);
+   * if (fork() == 0)
+   * {
+   *   // This is the child process.
+   *   my_execution_context.notify_fork(execution_context::fork_child);
+   * }
+   * else
+   * {
+   *   // This is the parent process.
+   *   my_execution_context.notify_fork(execution_context::fork_parent);
+   * } @endcode
+   *
+   * @note For each service object @c svc in the execution_context set,
+   * performs <tt>svc->notify_fork();</tt>. When processing the fork_prepare
+   * event, services are visited in reverse order of the beginning of service
+   * object lifetime. Otherwise, services are visited in order of the beginning
+   * of service object lifetime.
+   */
+  ASIO_DECL void notify_fork(fork_event event);
+
+  /// Obtain the service object corresponding to the given type.
+  /**
+   * This function is used to locate a service object that corresponds to the
+   * given service type. If there is no existing implementation of the service,
+   * then the execution_context will create a new instance of the service.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @return The service interface implementing the specified service type.
+   * Ownership of the service interface is not transferred to the caller.
+   */
+  template <typename Service>
+  friend Service& use_service(execution_context& e);
+
+  /// Obtain the service object corresponding to the given type.
+  /**
+   * This function is used to locate a service object that corresponds to the
+   * given service type. If there is no existing implementation of the service,
+   * then the io_context will create a new instance of the service.
+   *
+   * @param ioc The io_context object that owns the service.
+   *
+   * @return The service interface implementing the specified service type.
+   * Ownership of the service interface is not transferred to the caller.
+   *
+   * @note This overload is preserved for backwards compatibility with services
+   * that inherit from io_context::service.
+   */
+  template <typename Service>
+  friend Service& use_service(io_context& ioc);
+
+#if defined(GENERATING_DOCUMENTATION)
+
+  /// Creates a service object and adds it to the execution_context.
+  /**
+   * This function is used to add a service to the execution_context.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @param args Zero or more arguments to be passed to the service
+   * constructor.
+   *
+   * @throws asio::service_already_exists Thrown if a service of the
+   * given type is already present in the execution_context.
+   */
+  template <typename Service, typename... Args>
+  friend Service& make_service(execution_context& e, Args&&... args);
+
+#elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename Service, typename... Args>
+  friend Service& make_service(execution_context& e,
+      ASIO_MOVE_ARG(Args)... args);
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename Service>
+  friend Service& make_service(execution_context& e);
+
+#define ASIO_PRIVATE_MAKE_SERVICE_DEF(n) \
+  template <typename Service, ASIO_VARIADIC_TPARAMS(n)> \
+  friend Service& make_service(execution_context& e, \
+      ASIO_VARIADIC_MOVE_PARAMS(n)); \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_MAKE_SERVICE_DEF)
+#undef ASIO_PRIVATE_MAKE_SERVICE_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  /// (Deprecated: Use make_service().) Add a service object to the
+  /// execution_context.
+  /**
+   * This function is used to add a service to the execution_context.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @param svc The service object. On success, ownership of the service object
+   * is transferred to the execution_context. When the execution_context object
+   * is destroyed, it will destroy the service object by performing: @code
+   * delete static_cast<execution_context::service*>(svc) @endcode
+   *
+   * @throws asio::service_already_exists Thrown if a service of the
+   * given type is already present in the execution_context.
+   *
+   * @throws asio::invalid_service_owner Thrown if the service's owning
+   * execution_context is not the execution_context object specified by the
+   * @c e parameter.
+   */
+  template <typename Service>
+  friend void add_service(execution_context& e, Service* svc);
+
+  /// Determine if an execution_context contains a specified service type.
+  /**
+   * This function is used to determine whether the execution_context contains a
+   * service object corresponding to the given service type.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @return A boolean indicating whether the execution_context contains the
+   * service.
+   */
+  template <typename Service>
+  friend bool has_service(execution_context& e);
+
+private:
+  // The service registry.
+  asio::detail::service_registry* service_registry_;
+};
+
+/// Class used to uniquely identify a service.
+class execution_context::id
+  : private noncopyable
+{
+public:
+  /// Constructor.
+  id() {}
+};
+
+/// Base class for all io_context services.
+class execution_context::service
+  : private noncopyable
+{
+public:
+  /// Get the context object that owns the service.
+  execution_context& context();
+
+protected:
+  /// Constructor.
+  /**
+   * @param owner The execution_context object that owns the service.
+   */
+  ASIO_DECL service(execution_context& owner);
+
+  /// Destructor.
+  ASIO_DECL virtual ~service();
+
+private:
+  /// Destroy all user-defined handler objects owned by the service.
+  virtual void shutdown() = 0;
+
+  /// Handle notification of a fork-related event to perform any necessary
+  /// housekeeping.
+  /**
+   * This function is not a pure virtual so that services only have to
+   * implement it if necessary. The default implementation does nothing.
+   */
+  ASIO_DECL virtual void notify_fork(
+      execution_context::fork_event event);
+
+  friend class asio::detail::service_registry;
+  struct key
+  {
+    key() : type_info_(0), id_(0) {}
+    const std::type_info* type_info_;
+    const execution_context::id* id_;
+  } key_;
+
+  execution_context& owner_;
+  service* next_;
+};
+
+/// Exception thrown when trying to add a duplicate service to an
+/// execution_context.
+class service_already_exists
+  : public std::logic_error
+{
+public:
+  ASIO_DECL service_already_exists();
+};
+
+/// Exception thrown when trying to add a service object to an
+/// execution_context where the service has a different owner.
+class invalid_service_owner
+  : public std::logic_error
+{
+public:
+  ASIO_DECL invalid_service_owner();
+};
+
+namespace detail {
+
+// Special derived service id type to keep classes header-file only.
+template <typename Type>
+class service_id
+  : public execution_context::id
+{
+};
+
+// Special service base class to keep classes header-file only.
+template <typename Type>
+class execution_context_service_base
+  : public execution_context::service
+{
+public:
+  static service_id<Type> id;
+
+  // Constructor.
+  execution_context_service_base(execution_context& e)
+    : execution_context::service(e)
+  {
+  }
+};
+
+template <typename Type>
+service_id<Type> execution_context_service_base<Type>::id;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/execution_context.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/execution_context.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_EXECUTION_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/executor.hpp b/subprojects/asio/include/asio/executor.hpp
new file mode 100644
index 000000000..e552cfbf2
--- /dev/null
+++ b/subprojects/asio/include/asio/executor.hpp
@@ -0,0 +1,341 @@
+//
+// executor.hpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXECUTOR_HPP
+#define ASIO_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <typeinfo>
+#include "asio/detail/cstddef.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Exception thrown when trying to access an empty polymorphic executor.
+class bad_executor
+  : public std::exception
+{
+public:
+  /// Constructor.
+  ASIO_DECL bad_executor() ASIO_NOEXCEPT;
+
+  /// Obtain message associated with exception.
+  ASIO_DECL virtual const char* what() const
+    ASIO_NOEXCEPT_OR_NOTHROW;
+};
+
+/// Polymorphic wrapper for executors.
+class executor
+{
+public:
+  /// Default constructor.
+  executor() ASIO_NOEXCEPT
+    : impl_(0)
+  {
+  }
+
+  /// Construct from nullptr.
+  executor(nullptr_t) ASIO_NOEXCEPT
+    : impl_(0)
+  {
+  }
+
+  /// Copy constructor.
+  executor(const executor& other) ASIO_NOEXCEPT
+    : impl_(other.clone())
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move constructor.
+  executor(executor&& other) ASIO_NOEXCEPT
+    : impl_(other.impl_)
+  {
+    other.impl_ = 0;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Construct a polymorphic wrapper for the specified executor.
+  template <typename Executor>
+  executor(Executor e);
+
+  /// Allocator-aware constructor to create a polymorphic wrapper for the
+  /// specified executor.
+  template <typename Executor, typename Allocator>
+  executor(allocator_arg_t, const Allocator& a, Executor e);
+
+  /// Destructor.
+  ~executor()
+  {
+    destroy();
+  }
+
+  /// Assignment operator.
+  executor& operator=(const executor& other) ASIO_NOEXCEPT
+  {
+    destroy();
+    impl_ = other.clone();
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  // Move assignment operator.
+  executor& operator=(executor&& other) ASIO_NOEXCEPT
+  {
+    destroy();
+    impl_ = other.impl_;
+    other.impl_ = 0;
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Assignment operator for nullptr_t.
+  executor& operator=(nullptr_t) ASIO_NOEXCEPT
+  {
+    destroy();
+    impl_ = 0;
+    return *this;
+  }
+
+  /// Assignment operator to create a polymorphic wrapper for the specified
+  /// executor.
+  template <typename Executor>
+  executor& operator=(ASIO_MOVE_ARG(Executor) e) ASIO_NOEXCEPT
+  {
+    executor tmp(ASIO_MOVE_CAST(Executor)(e));
+    destroy();
+    impl_ = tmp.impl_;
+    tmp.impl_ = 0;
+    return *this;
+  }
+
+  /// Obtain the underlying execution context.
+  execution_context& context() const ASIO_NOEXCEPT
+  {
+    return get_impl()->context();
+  }
+
+  /// Inform the executor that it has some outstanding work to do.
+  void on_work_started() const ASIO_NOEXCEPT
+  {
+    get_impl()->on_work_started();
+  }
+
+  /// Inform the executor that some work is no longer outstanding.
+  void on_work_finished() const ASIO_NOEXCEPT
+  {
+    get_impl()->on_work_finished();
+  }
+
+  /// Request the executor to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object is executed according to the rules of the
+   * target executor object.
+   *
+   * @param f The function object to be called. The executor will make a copy
+   * of the handler object as required. The function signature of the function
+   * object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the executor to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object is executed according to the rules of the
+   * target executor object.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the executor to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object is executed according to the rules of the
+   * target executor object.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  struct unspecified_bool_type_t {};
+  typedef void (*unspecified_bool_type)(unspecified_bool_type_t);
+  static void unspecified_bool_true(unspecified_bool_type_t) {}
+
+  /// Operator to test if the executor contains a valid target.
+  operator unspecified_bool_type() const ASIO_NOEXCEPT
+  {
+    return impl_ ? &executor::unspecified_bool_true : 0;
+  }
+
+  /// Obtain type information for the target executor object.
+  /**
+   * @returns If @c *this has a target type of type @c T, <tt>typeid(T)</tt>;
+   * otherwise, <tt>typeid(void)</tt>.
+   */
+#if !defined(ASIO_NO_TYPEID) || defined(GENERATING_DOCUMENTATION)
+  const std::type_info& target_type() const ASIO_NOEXCEPT
+  {
+    return impl_ ? impl_->target_type() : typeid(void);
+  }
+#else // !defined(ASIO_NO_TYPEID) || defined(GENERATING_DOCUMENTATION)
+  const void* target_type() const ASIO_NOEXCEPT
+  {
+    return impl_ ? impl_->target_type() : 0;
+  }
+#endif // !defined(ASIO_NO_TYPEID) || defined(GENERATING_DOCUMENTATION)
+
+  /// Obtain a pointer to the target executor object.
+  /**
+   * @returns If <tt>target_type() == typeid(T)</tt>, a pointer to the stored
+   * executor target; otherwise, a null pointer.
+   */
+  template <typename Executor>
+  Executor* target() ASIO_NOEXCEPT;
+
+  /// Obtain a pointer to the target executor object.
+  /**
+   * @returns If <tt>target_type() == typeid(T)</tt>, a pointer to the stored
+   * executor target; otherwise, a null pointer.
+   */
+  template <typename Executor>
+  const Executor* target() const ASIO_NOEXCEPT;
+
+  /// Compare two executors for equality.
+  friend bool operator==(const executor& a,
+      const executor& b) ASIO_NOEXCEPT
+  {
+    if (a.impl_ == b.impl_)
+      return true;
+    if (!a.impl_ || !b.impl_)
+      return false;
+    return a.impl_->equals(b.impl_);
+  }
+
+  /// Compare two executors for inequality.
+  friend bool operator!=(const executor& a,
+      const executor& b) ASIO_NOEXCEPT
+  {
+    return !(a == b);
+  }
+
+private:
+#if !defined(GENERATING_DOCUMENTATION)
+  class function;
+  template <typename, typename> class impl;
+
+#if !defined(ASIO_NO_TYPEID)
+  typedef const std::type_info& type_id_result_type;
+#else // !defined(ASIO_NO_TYPEID)
+  typedef const void* type_id_result_type;
+#endif // !defined(ASIO_NO_TYPEID)
+
+  template <typename T>
+  static type_id_result_type type_id()
+  {
+#if !defined(ASIO_NO_TYPEID)
+    return typeid(T);
+#else // !defined(ASIO_NO_TYPEID)
+    static int unique_id;
+    return &unique_id;
+#endif // !defined(ASIO_NO_TYPEID)
+  }
+
+  // Base class for all polymorphic executor implementations.
+  class impl_base
+  {
+  public:
+    virtual impl_base* clone() const ASIO_NOEXCEPT = 0;
+    virtual void destroy() ASIO_NOEXCEPT = 0;
+    virtual execution_context& context() ASIO_NOEXCEPT = 0;
+    virtual void on_work_started() ASIO_NOEXCEPT = 0;
+    virtual void on_work_finished() ASIO_NOEXCEPT = 0;
+    virtual void dispatch(ASIO_MOVE_ARG(function)) = 0;
+    virtual void post(ASIO_MOVE_ARG(function)) = 0;
+    virtual void defer(ASIO_MOVE_ARG(function)) = 0;
+    virtual type_id_result_type target_type() const ASIO_NOEXCEPT = 0;
+    virtual void* target() ASIO_NOEXCEPT = 0;
+    virtual const void* target() const ASIO_NOEXCEPT = 0;
+    virtual bool equals(const impl_base* e) const ASIO_NOEXCEPT = 0;
+
+  protected:
+    impl_base(bool fast_dispatch) : fast_dispatch_(fast_dispatch) {}
+    virtual ~impl_base() {}
+
+  private:
+    friend class executor;
+    const bool fast_dispatch_;
+  };
+
+  // Helper function to check and return the implementation pointer.
+  impl_base* get_impl() const
+  {
+    if (!impl_)
+    {
+      bad_executor ex;
+      asio::detail::throw_exception(ex);
+    }
+    return impl_;
+  }
+
+  // Helper function to clone another implementation.
+  impl_base* clone() const ASIO_NOEXCEPT
+  {
+    return impl_ ? impl_->clone() : 0;
+  }
+
+  // Helper function to destroy an implementation.
+  void destroy() ASIO_NOEXCEPT
+  {
+    if (impl_)
+      impl_->destroy();
+  }
+
+  impl_base* impl_;
+#endif // !defined(GENERATING_DOCUMENTATION)
+};
+
+} // namespace asio
+
+ASIO_USES_ALLOCATOR(asio::executor)
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/executor.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/executor.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/executor_work_guard.hpp b/subprojects/asio/include/asio/executor_work_guard.hpp
new file mode 100644
index 000000000..1875f542b
--- /dev/null
+++ b/subprojects/asio/include/asio/executor_work_guard.hpp
@@ -0,0 +1,170 @@
+//
+// executor_work_guard.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXECUTOR_WORK_GUARD_HPP
+#define ASIO_EXECUTOR_WORK_GUARD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/is_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// An object of type @c executor_work_guard controls ownership of executor work
+/// within a scope.
+template <typename Executor>
+class executor_work_guard
+{
+public:
+  /// The underlying executor type.
+  typedef Executor executor_type;
+
+  /// Constructs a @c executor_work_guard object for the specified executor.
+  /**
+   * Stores a copy of @c e and calls <tt>on_work_started()</tt> on it.
+   */
+  explicit executor_work_guard(const executor_type& e) ASIO_NOEXCEPT
+    : executor_(e),
+      owns_(true)
+  {
+    executor_.on_work_started();
+  }
+
+  /// Copy constructor.
+  executor_work_guard(const executor_work_guard& other) ASIO_NOEXCEPT
+    : executor_(other.executor_),
+      owns_(other.owns_)
+  {
+    if (owns_)
+      executor_.on_work_started();
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move constructor.
+  executor_work_guard(executor_work_guard&& other)
+    : executor_(ASIO_MOVE_CAST(Executor)(other.executor_)),
+      owns_(other.owns_)
+  {
+    other.owns_ = false;
+  }
+#endif //  defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destructor.
+  /**
+   * Unless the object has already been reset, or is in a moved-from state,
+   * calls <tt>on_work_finished()</tt> on the stored executor.
+   */
+  ~executor_work_guard()
+  {
+    if (owns_)
+      executor_.on_work_finished();
+  }
+
+  /// Obtain the associated executor.
+  executor_type get_executor() const ASIO_NOEXCEPT
+  {
+    return executor_;
+  }
+
+  /// Whether the executor_work_guard object owns some outstanding work.
+  bool owns_work() const ASIO_NOEXCEPT
+  {
+    return owns_;
+  }
+
+  /// Indicate that the work is no longer outstanding.
+  /*
+   * Unless the object has already been reset, or is in a moved-from state,
+   * calls <tt>on_work_finished()</tt> on the stored executor.
+   */
+  void reset() ASIO_NOEXCEPT
+  {
+    if (owns_)
+    {
+      executor_.on_work_finished();
+      owns_ = false;
+    }
+  }
+
+private:
+  // Disallow assignment.
+  executor_work_guard& operator=(const executor_work_guard&);
+
+  executor_type executor_;
+  bool owns_;
+};
+
+/// Create an @ref executor_work_guard object.
+template <typename Executor>
+inline executor_work_guard<Executor> make_work_guard(const Executor& ex,
+    typename enable_if<is_executor<Executor>::value>::type* = 0)
+{
+  return executor_work_guard<Executor>(ex);
+}
+
+/// Create an @ref executor_work_guard object.
+template <typename ExecutionContext>
+inline executor_work_guard<typename ExecutionContext::executor_type>
+make_work_guard(ExecutionContext& ctx,
+    typename enable_if<
+      is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
+{
+  return executor_work_guard<typename ExecutionContext::executor_type>(
+      ctx.get_executor());
+}
+
+/// Create an @ref executor_work_guard object.
+template <typename T>
+inline executor_work_guard<typename associated_executor<T>::type>
+make_work_guard(const T& t,
+    typename enable_if<!is_executor<T>::value &&
+      !is_convertible<T&, execution_context&>::value>::type* = 0)
+{
+  return executor_work_guard<typename associated_executor<T>::type>(
+      associated_executor<T>::get(t));
+}
+
+/// Create an @ref executor_work_guard object.
+template <typename T, typename Executor>
+inline executor_work_guard<typename associated_executor<T, Executor>::type>
+make_work_guard(const T& t, const Executor& ex,
+    typename enable_if<is_executor<Executor>::value>::type* = 0)
+{
+  return executor_work_guard<typename associated_executor<T, Executor>::type>(
+      associated_executor<T, Executor>::get(t, ex));
+}
+
+/// Create an @ref executor_work_guard object.
+template <typename T, typename ExecutionContext>
+inline executor_work_guard<typename associated_executor<T,
+  typename ExecutionContext::executor_type>::type>
+make_work_guard(const T& t, ExecutionContext& ctx,
+    typename enable_if<!is_executor<T>::value &&
+      !is_convertible<T&, execution_context&>::value &&
+      is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
+{
+  return executor_work_guard<typename associated_executor<T,
+    typename ExecutionContext::executor_type>::type>(
+      associated_executor<T, typename ExecutionContext::executor_type>::get(
+        t, ctx.get_executor()));
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_EXECUTOR_WORK_GUARD_HPP
diff --git a/subprojects/asio/include/asio/experimental.hpp b/subprojects/asio/include/asio/experimental.hpp
new file mode 100644
index 000000000..5765c37d0
--- /dev/null
+++ b/subprojects/asio/include/asio/experimental.hpp
@@ -0,0 +1,22 @@
+//
+// experimental.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXPERIMENTAL_HPP
+#define ASIO_EXPERIMENTAL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/experimental/co_spawn.hpp"
+#include "asio/experimental/detached.hpp"
+#include "asio/experimental/redirect_error.hpp"
+
+#endif // ASIO_EXPERIMENTAL_HPP
diff --git a/subprojects/asio/include/asio/experimental/co_spawn.hpp b/subprojects/asio/include/asio/experimental/co_spawn.hpp
new file mode 100644
index 000000000..cbf5bc525
--- /dev/null
+++ b/subprojects/asio/include/asio/experimental/co_spawn.hpp
@@ -0,0 +1,226 @@
+//
+// experimental/co_spawn.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXPERIMENTAL_CO_SPAWN_HPP
+#define ASIO_EXPERIMENTAL_CO_SPAWN_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION)
+
+#include <experimental/coroutine>
+#include "asio/executor.hpp"
+#include "asio/strand.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+namespace detail {
+
+using std::experimental::coroutine_handle;
+
+template <typename> class awaiter;
+template <typename> class awaitee_base;
+template <typename, typename> class awaitee;
+template <typename, typename> class await_handler_base;
+template <typename Executor, typename F, typename CompletionToken>
+auto co_spawn(const Executor& ex, F&& f, CompletionToken&& token);
+
+} // namespace detail
+
+namespace this_coro {
+
+/// Awaitable type that returns a completion token for the current coroutine.
+struct token_t {};
+
+/// Awaitable object that returns a completion token for the current coroutine.
+constexpr inline token_t token() { return {}; }
+
+/// Awaitable type that returns the executor of the current coroutine.
+struct executor_t {};
+
+/// Awaitable object that returns the executor of the current coroutine.
+constexpr inline executor_t executor() { return {}; }
+
+} // namespace this_coro
+
+/// A completion token that represents the currently executing coroutine.
+/**
+ * The await_token class is used to represent the currently executing
+ * coroutine. An await_token may be passed as a handler to an asynchronous
+ * operation. For example:
+ *
+ * @code awaitable<void> my_coroutine()
+ * {
+ *   await_token token = co_await this_coro::token();
+ *   ...
+ *   std::size_t n = co_await my_socket.async_read_some(buffer, token);
+ *   ...
+ * } @endcode
+ *
+ * The initiating function (async_read_some in the above example) suspends the
+ * current coroutine. The coroutine is resumed when the asynchronous operation
+ * completes, and the result of the operation is returned.
+ */
+template <typename Executor>
+class await_token
+{
+public:
+  /// The associated executor type.
+  typedef Executor executor_type;
+
+  /// Copy constructor.
+  await_token(const await_token& other) noexcept
+    : awaiter_(other.awaiter_)
+  {
+  }
+
+  /// Move constructor.
+  await_token(await_token&& other) noexcept
+    : awaiter_(std::exchange(other.awaiter_, nullptr))
+  {
+  }
+
+  /// Get the associated executor.
+  executor_type get_executor() const noexcept
+  {
+    return awaiter_->get_executor();
+  }
+
+private:
+  // No assignment allowed.
+  await_token& operator=(const await_token&) = delete;
+
+  template <typename> friend class detail::awaitee_base;
+  template <typename, typename> friend class detail::await_handler_base;
+
+  // Private constructor used by awaitee_base.
+  explicit await_token(detail::awaiter<Executor>* a)
+    : awaiter_(a)
+  {
+  }
+
+  detail::awaiter<Executor>* awaiter_;
+};
+
+/// The return type of a coroutine or asynchronous operation.
+template <typename T, typename Executor = strand<executor>>
+class awaitable
+{
+public:
+  /// The type of the awaited value.
+  typedef T value_type;
+
+  /// The executor type that will be used for the coroutine.
+  typedef Executor executor_type;
+
+  /// Move constructor.
+  awaitable(awaitable&& other) noexcept
+    : awaitee_(std::exchange(other.awaitee_, nullptr))
+  {
+  }
+
+  /// Destructor
+  ~awaitable()
+  {
+    if (awaitee_)
+    {
+      detail::coroutine_handle<
+        detail::awaitee<T, Executor>>::from_promise(
+          *awaitee_).destroy();
+    }
+  }
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+  // Support for co_await keyword.
+  bool await_ready() const noexcept
+  {
+    return awaitee_->ready();
+  }
+
+  // Support for co_await keyword.
+  void await_suspend(detail::coroutine_handle<detail::awaiter<Executor>> h)
+  {
+    awaitee_->attach_caller(h);
+  }
+
+  // Support for co_await keyword.
+  template <class U>
+  void await_suspend(detail::coroutine_handle<detail::awaitee<U, Executor>> h)
+  {
+    awaitee_->attach_caller(h);
+  }
+
+  // Support for co_await keyword.
+  T await_resume()
+  {
+    return awaitee_->get();
+  }
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+private:
+  template <typename, typename> friend class detail::awaitee;
+  template <typename, typename> friend class detail::await_handler_base;
+
+  // Not copy constructible or copy assignable.
+  awaitable(const awaitable&) = delete;
+  awaitable& operator=(const awaitable&) = delete;
+
+  // Construct the awaitable from a coroutine's promise object.
+  explicit awaitable(detail::awaitee<T, Executor>* a) : awaitee_(a) {}
+
+  detail::awaitee<T, Executor>* awaitee_;
+};
+
+/// Spawn a new thread of execution.
+template <typename Executor, typename F, typename CompletionToken,
+    typename = typename enable_if<is_executor<Executor>::value>::type>
+inline auto co_spawn(const Executor& ex, F&& f, CompletionToken&& token)
+{
+  return detail::co_spawn(ex, std::forward<F>(f),
+      std::forward<CompletionToken>(token));
+}
+
+/// Spawn a new thread of execution.
+template <typename ExecutionContext, typename F, typename CompletionToken,
+    typename = typename enable_if<
+      is_convertible<ExecutionContext&, execution_context&>::value>::type>
+inline auto co_spawn(ExecutionContext& ctx, F&& f, CompletionToken&& token)
+{
+  return detail::co_spawn(ctx.get_executor(), std::forward<F>(f),
+      std::forward<CompletionToken>(token));
+}
+
+/// Spawn a new thread of execution.
+template <typename Executor, typename F, typename CompletionToken>
+inline auto co_spawn(const await_token<Executor>& parent,
+    F&& f, CompletionToken&& token)
+{
+  return detail::co_spawn(parent.get_executor(), std::forward<F>(f),
+      std::forward<CompletionToken>(token));
+}
+
+} // namespace experimental
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/experimental/impl/co_spawn.hpp"
+
+#endif // defined(ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_EXPERIMENTAL_CO_SPAWN_HPP
diff --git a/subprojects/asio/include/asio/experimental/detached.hpp b/subprojects/asio/include/asio/experimental/detached.hpp
new file mode 100644
index 000000000..d484f18fb
--- /dev/null
+++ b/subprojects/asio/include/asio/experimental/detached.hpp
@@ -0,0 +1,65 @@
+//
+// experimental/detached.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXPERIMENTAL_DETACHED_HPP
+#define ASIO_EXPERIMENTAL_DETACHED_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <memory>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+
+/// Class used to specify that an asynchronous operation is detached.
+/**
+
+ * The detached_t class is used to indicate that an asynchronous operation is
+ * detached. That is, there is no completion handler waiting for the
+ * operation's result. A detached_t object may be passed as a handler to an
+ * asynchronous operation, typically using the special value
+ * @c asio::experimental::detached. For example:
+
+ * @code my_socket.async_send(my_buffer, asio::experimental::detached);
+ * @endcode
+ */
+class detached_t
+{
+public:
+  /// Constructor. 
+  ASIO_CONSTEXPR detached_t()
+  {
+  }
+};
+
+/// A special value, similar to std::nothrow.
+/**
+ * See the documentation for asio::experimental::detached_t for a usage
+ * example.
+ */
+#if defined(ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION)
+constexpr detached_t detached;
+#elif defined(ASIO_MSVC)
+__declspec(selectany) detached_t detached;
+#endif
+
+} // namespace experimental
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/experimental/impl/detached.hpp"
+
+#endif // ASIO_EXPERIMENTAL_DETACHED_HPP
diff --git a/subprojects/asio/include/asio/experimental/impl/co_spawn.hpp b/subprojects/asio/include/asio/experimental/impl/co_spawn.hpp
new file mode 100644
index 000000000..8263eff96
--- /dev/null
+++ b/subprojects/asio/include/asio/experimental/impl/co_spawn.hpp
@@ -0,0 +1,876 @@
+//
+// experimental/impl/co_spawn.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXPERIMENTAL_IMPL_CO_SPAWN_HPP
+#define ASIO_EXPERIMENTAL_IMPL_CO_SPAWN_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <exception>
+#include <functional>
+#include <memory>
+#include <new>
+#include <tuple>
+#include <utility>
+#include "asio/async_result.hpp"
+#include "asio/detail/thread_context.hpp"
+#include "asio/detail/thread_info_base.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/dispatch.hpp"
+#include "asio/post.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+namespace detail {
+
+// Promise object for coroutine at top of thread-of-execution "stack".
+template <typename Executor>
+class awaiter
+{
+public:
+  struct deleter
+  {
+    void operator()(awaiter* a)
+    {
+      if (a)
+        a->release();
+    }
+  };
+
+  typedef std::unique_ptr<awaiter, deleter> ptr;
+
+  typedef Executor executor_type;
+
+  ~awaiter()
+  {
+    if (has_executor_)
+      static_cast<Executor*>(static_cast<void*>(executor_))->~Executor();
+  }
+
+  void set_executor(const Executor& ex)
+  {
+    new (&executor_) Executor(ex);
+    has_executor_ = true;
+  }
+
+  executor_type get_executor() const noexcept
+  {
+    return *static_cast<const Executor*>(static_cast<const void*>(executor_));
+  }
+
+  awaiter* get_return_object()
+  {
+    return this;
+  }
+
+  auto initial_suspend()
+  {
+    return std::experimental::suspend_always();
+  }
+
+  auto final_suspend()
+  {
+    return std::experimental::suspend_always();
+  }
+
+  void return_void()
+  {
+  }
+
+  awaiter* add_ref()
+  {
+    ++ref_count_;
+    return this;
+  }
+
+  void release()
+  {
+    if (--ref_count_ == 0)
+      coroutine_handle<awaiter>::from_promise(*this).destroy();
+  }
+
+  void unhandled_exception()
+  {
+    pending_exception_ = std::current_exception();
+  }
+
+  void rethrow_unhandled_exception()
+  {
+    if (pending_exception_)
+    {
+      std::exception_ptr ex = std::exchange(pending_exception_, nullptr);
+      std::rethrow_exception(ex);
+    }
+  }
+
+private:
+  std::size_t ref_count_ = 0;
+  std::exception_ptr pending_exception_ = nullptr;
+  alignas(Executor) unsigned char executor_[sizeof(Executor)];
+  bool has_executor_ = false;
+};
+
+// Base promise for coroutines further down the thread-of-execution "stack".
+template <typename Executor>
+class awaitee_base
+{
+public:
+#if !defined(ASIO_DISABLE_AWAITEE_RECYCLING)
+  void* operator new(std::size_t size)
+  {
+    return asio::detail::thread_info_base::allocate(
+        asio::detail::thread_info_base::awaitee_tag(),
+        asio::detail::thread_context::thread_call_stack::top(),
+        size);
+  }
+
+  void operator delete(void* pointer, std::size_t size)
+  {
+    asio::detail::thread_info_base::deallocate(
+        asio::detail::thread_info_base::awaitee_tag(),
+        asio::detail::thread_context::thread_call_stack::top(),
+        pointer, size);
+  }
+#endif // !defined(ASIO_DISABLE_AWAITEE_RECYCLING)
+
+  auto initial_suspend()
+  {
+    return std::experimental::suspend_never();
+  }
+
+  struct final_suspender
+  {
+    awaitee_base* this_;
+
+    bool await_ready() const noexcept
+    {
+      return false;
+    }
+
+    void await_suspend(coroutine_handle<void>)
+    {
+      this_->wake_caller();
+    }
+
+    void await_resume() const noexcept
+    {
+    }
+  };
+
+  auto final_suspend()
+  {
+    return final_suspender{this};
+  }
+
+  void set_except(std::exception_ptr e)
+  {
+    pending_exception_ = e;
+  }
+
+  void unhandled_exception()
+  {
+    set_except(std::current_exception());
+  }
+
+  void rethrow_exception()
+  {
+    if (pending_exception_)
+    {
+      std::exception_ptr ex = std::exchange(pending_exception_, nullptr);
+      std::rethrow_exception(ex);
+    }
+  }
+
+  awaiter<Executor>* top()
+  {
+    return awaiter_;
+  }
+
+  coroutine_handle<void> caller()
+  {
+    return caller_;
+  }
+
+  bool ready() const
+  {
+    return ready_;
+  }
+
+  void wake_caller()
+  {
+    if (caller_)
+      caller_.resume();
+    else
+      ready_ = true;
+  }
+
+  class awaitable_executor
+  {
+  public:
+    explicit awaitable_executor(awaitee_base* a)
+      : this_(a)
+    {
+    }
+
+    bool await_ready() const noexcept
+    {
+      return this_->awaiter_ != nullptr;
+    }
+
+    template <typename U, typename Ex>
+    void await_suspend(coroutine_handle<detail::awaitee<U, Ex>> h) noexcept
+    {
+      this_->resume_on_attach_ = h;
+    }
+
+    Executor await_resume()
+    {
+      return this_->awaiter_->get_executor();
+    }
+
+  private:
+    awaitee_base* this_;
+  };
+
+  awaitable_executor await_transform(this_coro::executor_t) noexcept
+  {
+    return awaitable_executor(this);
+  }
+
+  class awaitable_token
+  {
+  public:
+    explicit awaitable_token(awaitee_base* a)
+      : this_(a)
+    {
+    }
+
+    bool await_ready() const noexcept
+    {
+      return this_->awaiter_ != nullptr;
+    }
+
+    template <typename U, typename Ex>
+    void await_suspend(coroutine_handle<detail::awaitee<U, Ex>> h) noexcept
+    {
+      this_->resume_on_attach_ = h;
+    }
+
+    await_token<Executor> await_resume()
+    {
+      return await_token<Executor>(this_->awaiter_);
+    }
+
+  private:
+    awaitee_base* this_;
+  };
+
+  awaitable_token await_transform(this_coro::token_t) noexcept
+  {
+    return awaitable_token(this);
+  }
+
+  template <typename T>
+  awaitable<T, Executor> await_transform(awaitable<T, Executor>& t) const
+  {
+    return std::move(t);
+  }
+
+  template <typename T>
+  awaitable<T, Executor> await_transform(awaitable<T, Executor>&& t) const
+  {
+    return std::move(t);
+  }
+
+  std::experimental::suspend_always await_transform(
+      std::experimental::suspend_always) const
+  {
+    return std::experimental::suspend_always();
+  }
+
+  void attach_caller(coroutine_handle<awaiter<Executor>> h)
+  {
+    this->caller_ = h;
+    this->attach_callees(&h.promise());
+  }
+
+  template <typename U>
+  void attach_caller(coroutine_handle<awaitee<U, Executor>> h)
+  {
+    this->caller_ = h;
+    if (h.promise().awaiter_)
+      this->attach_callees(h.promise().awaiter_);
+    else
+      h.promise().unattached_callee_ = this;
+  }
+
+  void attach_callees(awaiter<Executor>* a)
+  {
+    for (awaitee_base* curr = this; curr != nullptr;
+        curr = std::exchange(curr->unattached_callee_, nullptr))
+    {
+      curr->awaiter_ = a;
+      if (curr->resume_on_attach_)
+        return std::exchange(curr->resume_on_attach_, nullptr).resume();
+    }
+  }
+
+protected:
+  awaiter<Executor>* awaiter_ = nullptr;
+  coroutine_handle<void> caller_ = nullptr;
+  awaitee_base<Executor>* unattached_callee_ = nullptr;
+  std::exception_ptr pending_exception_ = nullptr;
+  coroutine_handle<void> resume_on_attach_ = nullptr;
+  bool ready_ = false;
+};
+
+// Promise object for coroutines further down the thread-of-execution "stack".
+template <typename T, typename Executor>
+class awaitee
+  : public awaitee_base<Executor>
+{
+public:
+  awaitee()
+  {
+  }
+
+  awaitee(awaitee&& other) noexcept
+    : awaitee_base<Executor>(std::move(other))
+  {
+  }
+
+  ~awaitee()
+  {
+    if (has_result_)
+      static_cast<T*>(static_cast<void*>(result_))->~T();
+  }
+
+  awaitable<T, Executor> get_return_object()
+  {
+    return awaitable<T, Executor>(this);
+  };
+
+  template <typename U>
+  void return_value(U&& u)
+  {
+    new (&result_) T(std::forward<U>(u));
+    has_result_ = true;
+  }
+
+  T get()
+  {
+    this->caller_ = nullptr;
+    this->rethrow_exception();
+    return std::move(*static_cast<T*>(static_cast<void*>(result_)));
+  }
+
+private:
+  alignas(T) unsigned char result_[sizeof(T)];
+  bool has_result_ = false;
+};
+
+// Promise object for coroutines further down the thread-of-execution "stack".
+template <typename Executor>
+class awaitee<void, Executor>
+  : public awaitee_base<Executor>
+{
+public:
+  awaitable<void, Executor> get_return_object()
+  {
+    return awaitable<void, Executor>(this);
+  };
+
+  void return_void()
+  {
+  }
+
+  void get()
+  {
+    this->caller_ = nullptr;
+    this->rethrow_exception();
+  }
+};
+
+template <typename Executor>
+class awaiter_task
+{
+public:
+  typedef Executor executor_type;
+
+  awaiter_task(awaiter<Executor>* a)
+    : awaiter_(a->add_ref())
+  {
+  }
+
+  awaiter_task(awaiter_task&& other) noexcept
+    : awaiter_(std::exchange(other.awaiter_, nullptr))
+  {
+  }
+
+  ~awaiter_task()
+  {
+    if (awaiter_)
+    {
+      // Coroutine "stack unwinding" must be performed through the executor.
+      executor_type ex(awaiter_->get_executor());
+      (post)(ex,
+          [a = std::move(awaiter_)]() mutable
+          {
+            typename awaiter<Executor>::ptr(std::move(a));
+          });
+    }
+  }
+
+  executor_type get_executor() const noexcept
+  {
+    return awaiter_->get_executor();
+  }
+
+protected:
+  typename awaiter<Executor>::ptr awaiter_;
+};
+
+template <typename Executor>
+class co_spawn_handler : public awaiter_task<Executor>
+{
+public:
+  using awaiter_task<Executor>::awaiter_task;
+
+  void operator()()
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    coroutine_handle<awaiter<Executor>>::from_promise(*ptr.get()).resume();
+  }
+};
+
+template <typename Executor, typename T>
+class await_handler_base : public awaiter_task<Executor>
+{
+public:
+  typedef awaitable<T, Executor> awaitable_type;
+
+  await_handler_base(await_token<Executor> token)
+    : awaiter_task<Executor>(token.awaiter_),
+      awaitee_(nullptr)
+  {
+  }
+
+  await_handler_base(await_handler_base&& other) noexcept
+    : awaiter_task<Executor>(std::move(other)),
+      awaitee_(std::exchange(other.awaitee_, nullptr))
+  {
+  }
+
+  void attach_awaitee(const awaitable<T, Executor>& a)
+  {
+    awaitee_ = a.awaitee_;
+  }
+
+protected:
+  awaitee<T, Executor>* awaitee_;
+};
+
+template <typename, typename...> class await_handler;
+
+template <typename Executor>
+class await_handler<Executor, void>
+  : public await_handler_base<Executor, void>
+{
+public:
+  using await_handler_base<Executor, void>::await_handler_base;
+
+  void operator()()
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    this->awaitee_->return_void();
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor>
+class await_handler<Executor, asio::error_code>
+  : public await_handler_base<Executor, void>
+{
+public:
+  typedef void return_type;
+
+  using await_handler_base<Executor, void>::await_handler_base;
+
+  void operator()(const asio::error_code& ec)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    if (ec)
+    {
+      this->awaitee_->set_except(
+          std::make_exception_ptr(asio::system_error(ec)));
+    }
+    else
+      this->awaitee_->return_void();
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor>
+class await_handler<Executor, std::exception_ptr>
+  : public await_handler_base<Executor, void>
+{
+public:
+  using await_handler_base<Executor, void>::await_handler_base;
+
+  void operator()(std::exception_ptr ex)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    if (ex)
+      this->awaitee_->set_except(ex);
+    else
+      this->awaitee_->return_void();
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor, typename T>
+class await_handler<Executor, T>
+  : public await_handler_base<Executor, T>
+{
+public:
+  using await_handler_base<Executor, T>::await_handler_base;
+
+  template <typename Arg>
+  void operator()(Arg&& arg)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    this->awaitee_->return_value(std::forward<Arg>(arg));
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor, typename T>
+class await_handler<Executor, asio::error_code, T>
+  : public await_handler_base<Executor, T>
+{
+public:
+  using await_handler_base<Executor, T>::await_handler_base;
+
+  template <typename Arg>
+  void operator()(const asio::error_code& ec, Arg&& arg)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    if (ec)
+    {
+      this->awaitee_->set_except(
+          std::make_exception_ptr(asio::system_error(ec)));
+    }
+    else
+      this->awaitee_->return_value(std::forward<Arg>(arg));
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor, typename T>
+class await_handler<Executor, std::exception_ptr, T>
+  : public await_handler_base<Executor, T>
+{
+public:
+  using await_handler_base<Executor, T>::await_handler_base;
+
+  template <typename Arg>
+  void operator()(std::exception_ptr ex, Arg&& arg)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    if (ex)
+      this->awaitee_->set_except(ex);
+    else
+      this->awaitee_->return_value(std::forward<Arg>(arg));
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor, typename... Ts>
+class await_handler
+  : public await_handler_base<Executor, std::tuple<Ts...>>
+{
+public:
+  using await_handler_base<Executor, std::tuple<Ts...>>::await_handler_base;
+
+  template <typename... Args>
+  void operator()(Args&&... args)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    this->awaitee_->return_value(
+        std::forward_as_tuple(std::forward<Args>(args)...));
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor, typename... Ts>
+class await_handler<Executor, asio::error_code, Ts...>
+  : public await_handler_base<Executor, std::tuple<Ts...>>
+{
+public:
+  using await_handler_base<Executor, std::tuple<Ts...>>::await_handler_base;
+
+  template <typename... Args>
+  void operator()(const asio::error_code& ec, Args&&... args)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    if (ec)
+    {
+      this->awaitee_->set_except(
+          std::make_exception_ptr(asio::system_error(ec)));
+    }
+    else
+    {
+      this->awaitee_->return_value(
+          std::forward_as_tuple(std::forward<Args>(args)...));
+    }
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename Executor, typename... Ts>
+class await_handler<Executor, std::exception_ptr, Ts...>
+  : public await_handler_base<Executor, std::tuple<Ts...>>
+{
+public:
+  using await_handler_base<Executor, std::tuple<Ts...>>::await_handler_base;
+
+  template <typename... Args>
+  void operator()(std::exception_ptr ex, Args&&... args)
+  {
+    typename awaiter<Executor>::ptr ptr(std::move(this->awaiter_));
+    if (ex)
+      this->awaitee_->set_except(ex);
+    else
+    {
+      this->awaitee_->return_value(
+          std::forward_as_tuple(std::forward<Args>(args)...));
+    }
+    this->awaitee_->wake_caller();
+    ptr->rethrow_unhandled_exception();
+  }
+};
+
+template <typename T>
+struct awaitable_signature;
+
+template <typename T, typename Executor>
+struct awaitable_signature<awaitable<T, Executor>>
+{
+  typedef void type(std::exception_ptr, T);
+};
+
+template <typename Executor>
+struct awaitable_signature<awaitable<void, Executor>>
+{
+  typedef void type(std::exception_ptr);
+};
+
+template <typename T, typename Executor, typename F, typename Handler>
+awaiter<Executor>* co_spawn_entry_point(awaitable<T, Executor>*,
+    executor_work_guard<Executor> work_guard, F f, Handler handler)
+{
+  bool done = false;
+
+  try
+  {
+    T t = co_await f();
+
+    done = true;
+
+    (dispatch)(work_guard.get_executor(),
+        [handler = std::move(handler), t = std::move(t)]() mutable
+        {
+          handler(std::exception_ptr(), std::move(t));
+        });
+  }
+  catch (...)
+  {
+    if (done)
+      throw;
+
+    (dispatch)(work_guard.get_executor(),
+        [handler = std::move(handler), e = std::current_exception()]() mutable
+        {
+          handler(e, T());
+        });
+  }
+}
+
+template <typename Executor, typename F, typename Handler>
+awaiter<Executor>* co_spawn_entry_point(awaitable<void, Executor>*,
+    executor_work_guard<Executor> work_guard, F f, Handler handler)
+{
+  std::exception_ptr e = nullptr;
+
+  try
+  {
+    co_await f();
+  }
+  catch (...)
+  {
+    e = std::current_exception();
+  }
+
+  (dispatch)(work_guard.get_executor(),
+      [handler = std::move(handler), e]() mutable
+      {
+        handler(e);
+      });
+}
+
+template <typename Executor, typename F, typename CompletionToken>
+auto co_spawn(const Executor& ex, F&& f, CompletionToken&& token)
+{
+  typedef typename result_of<F()>::type awaitable_type;
+  typedef typename awaitable_type::executor_type executor_type;
+  typedef typename awaitable_signature<awaitable_type>::type signature_type;
+
+  async_completion<CompletionToken, signature_type> completion(token);
+
+  executor_type ex2(ex);
+  auto work_guard = make_work_guard(completion.completion_handler, ex2);
+
+  auto* a = (co_spawn_entry_point)(
+      static_cast<awaitable_type*>(nullptr), std::move(work_guard),
+      std::forward<F>(f), std::move(completion.completion_handler));
+
+  a->set_executor(ex2);
+  (post)(co_spawn_handler<executor_type>(a));
+
+  return completion.result.get();
+}
+
+#if defined(_MSC_VER)
+# pragma warning(push)
+# pragma warning(disable:4033)
+#endif // defined(_MSC_VER)
+
+#if defined(_MSC_VER)
+template <typename T> T dummy_return()
+{
+  return std::move(*static_cast<T*>(nullptr));
+}
+
+template <>
+inline void dummy_return()
+{
+}
+#endif // defined(_MSC_VER)
+
+template <typename Awaitable>
+inline Awaitable make_dummy_awaitable()
+{
+  for (;;) co_await std::experimental::suspend_always();
+#if defined(_MSC_VER)
+  co_return dummy_return<typename Awaitable::value_type>();
+#endif // defined(_MSC_VER)
+}
+
+#if defined(_MSC_VER)
+# pragma warning(pop)
+#endif // defined(_MSC_VER)
+
+} // namespace detail
+} // namespace experimental
+
+template <typename Executor, typename R, typename... Args>
+class async_result<experimental::await_token<Executor>, R(Args...)>
+{
+public:
+  typedef experimental::detail::await_handler<
+    Executor, typename decay<Args>::type...> completion_handler_type;
+
+  typedef typename experimental::detail::await_handler<
+    Executor, Args...>::awaitable_type return_type;
+
+  async_result(completion_handler_type& h)
+    : awaitable_(experimental::detail::make_dummy_awaitable<return_type>())
+  {
+    h.attach_awaitee(awaitable_);
+  }
+
+  return_type get()
+  {
+    return std::move(awaitable_);
+  }
+
+private:
+  return_type awaitable_;
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+template <typename Executor, typename R, typename... Args>
+struct handler_type<experimental::await_token<Executor>, R(Args...)>
+{
+  typedef experimental::detail::await_handler<
+    Executor, typename decay<Args>::type...> type;
+};
+
+template <typename Executor, typename... Args>
+class async_result<experimental::detail::await_handler<Executor, Args...>>
+{
+public:
+  typedef typename experimental::detail::await_handler<
+    Executor, Args...>::awaitable_type type;
+
+  async_result(experimental::detail::await_handler<Executor, Args...>& h)
+    : awaitable_(experimental::detail::make_dummy_awaitable<type>())
+  {
+    h.attach_awaitee(awaitable_);
+  }
+
+  type get()
+  {
+    return std::move(awaitable_);
+  }
+
+private:
+  type awaitable_;
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+} // namespace asio
+
+namespace std { namespace experimental {
+
+template <typename Executor, typename... Args>
+struct coroutine_traits<
+  asio::experimental::detail::awaiter<Executor>*, Args...>
+{
+  typedef asio::experimental::detail::awaiter<Executor> promise_type;
+};
+
+template <typename T, typename Executor, typename... Args>
+struct coroutine_traits<
+  asio::experimental::awaitable<T, Executor>, Args...>
+{
+  typedef asio::experimental::detail::awaitee<T, Executor> promise_type;
+};
+
+}} // namespace std::experimental
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_EXPERIMENTAL_IMPL_CO_SPAWN_HPP
diff --git a/subprojects/asio/include/asio/experimental/impl/detached.hpp b/subprojects/asio/include/asio/experimental/impl/detached.hpp
new file mode 100644
index 000000000..6ce88872e
--- /dev/null
+++ b/subprojects/asio/include/asio/experimental/impl/detached.hpp
@@ -0,0 +1,91 @@
+//
+// experimental/impl/detached.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXPERIMENTAL_IMPL_DETACHED_HPP
+#define ASIO_EXPERIMENTAL_IMPL_DETACHED_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/async_result.hpp"
+#include "asio/detail/variadic_templates.hpp"
+#include "asio/handler_type.hpp"
+#include "asio/system_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+namespace detail {
+
+  // Class to adapt a detached_t as a completion handler.
+  class detached_handler
+  {
+  public:
+    detached_handler(detached_t)
+    {
+    }
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+    template <typename... Args>
+    void operator()(Args...)
+    {
+    }
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+    void operator()()
+    {
+    }
+
+#define ASIO_PRIVATE_DETACHED_DEF(n) \
+    template <ASIO_VARIADIC_TPARAMS(n)> \
+    void operator()(ASIO_VARIADIC_BYVAL_PARAMS(n)) \
+    { \
+    } \
+    /**/
+    ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_DETACHED_DEF)
+#undef ASIO_PRIVATE_DETACHED_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+  };
+
+} // namespace detail
+} // namespace experimental
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename Signature>
+struct async_result<experimental::detached_t, Signature>
+{
+  typedef asio::experimental::detail::detached_handler
+    completion_handler_type;
+
+  typedef void return_type;
+
+  explicit async_result(completion_handler_type&)
+  {
+  }
+
+  void get()
+  {
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_EXPERIMENTAL_IMPL_DETACHED_HPP
diff --git a/subprojects/asio/include/asio/experimental/impl/redirect_error.hpp b/subprojects/asio/include/asio/experimental/impl/redirect_error.hpp
new file mode 100644
index 000000000..d3b97facc
--- /dev/null
+++ b/subprojects/asio/include/asio/experimental/impl/redirect_error.hpp
@@ -0,0 +1,294 @@
+//
+// experimental/impl/redirect_error.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXPERIMENTAL_IMPL_REDIRECT_ERROR_HPP
+#define ASIO_EXPERIMENTAL_IMPL_REDIRECT_ERROR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/async_result.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/detail/variadic_templates.hpp"
+#include "asio/handler_type.hpp"
+#include "asio/system_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+namespace detail {
+
+// Class to adapt a redirect_error_t as a completion handler.
+template <typename Handler>
+class redirect_error_handler
+{
+public:
+  template <typename CompletionToken>
+  redirect_error_handler(redirect_error_t<CompletionToken> e)
+    : ec_(e.ec_),
+      handler_(ASIO_MOVE_CAST(CompletionToken)(e.token_))
+  {
+  }
+
+  void operator()()
+  {
+    handler_();
+  }
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename Arg, typename... Args>
+  typename enable_if<
+    !is_same<typename decay<Arg>::type, asio::error_code>::value
+  >::type
+  operator()(ASIO_MOVE_ARG(Arg) arg, ASIO_MOVE_ARG(Args)... args)
+  {
+    handler_(ASIO_MOVE_CAST(Arg)(arg),
+        ASIO_MOVE_CAST(Args)(args)...);
+  }
+
+  template <typename... Args>
+  void operator()(const asio::error_code& ec,
+      ASIO_MOVE_ARG(Args)... args)
+  {
+    ec_ = ec;
+    handler_(ASIO_MOVE_CAST(Args)(args)...);
+  }
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename Arg>
+  typename enable_if<
+    !is_same<typename decay<Arg>::type, asio::error_code>::value
+  >::type
+  operator()(ASIO_MOVE_ARG(Arg) arg)
+  {
+    handler_(ASIO_MOVE_CAST(Arg)(arg));
+  }
+
+  void operator()(const asio::error_code& ec)
+  {
+    ec_ = ec;
+    handler_();
+  }
+
+#define ASIO_PRIVATE_REDIRECT_ERROR_DEF(n) \
+  template <typename Arg, ASIO_VARIADIC_TPARAMS(n)> \
+  typename enable_if< \
+    !is_same<typename decay<Arg>::type, asio::error_code>::value \
+  >::type \
+  operator()(ASIO_MOVE_ARG(Arg) arg, ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    handler_(ASIO_MOVE_CAST(Arg)(arg), \
+        ASIO_VARIADIC_MOVE_ARGS(n)); \
+  } \
+  \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  void operator()(const asio::error_code& ec, \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    ec_ = ec; \
+    handler_(ASIO_VARIADIC_MOVE_ARGS(n)); \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_REDIRECT_ERROR_DEF)
+#undef ASIO_PRIVATE_REDIRECT_ERROR_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+//private:
+  asio::error_code& ec_;
+  Handler handler_;
+};
+
+template <typename Handler>
+inline void* asio_handler_allocate(std::size_t size,
+    redirect_error_handler<Handler>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Handler>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    redirect_error_handler<Handler>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Handler>
+inline bool asio_handler_is_continuation(
+    redirect_error_handler<Handler>* this_handler)
+{
+  return asio_handler_cont_helpers::is_continuation(
+        this_handler->handler_);
+}
+
+template <typename Function, typename Handler>
+inline void asio_handler_invoke(Function& function,
+    redirect_error_handler<Handler>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Function, typename Handler>
+inline void asio_handler_invoke(const Function& function,
+    redirect_error_handler<Handler>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Signature>
+struct redirect_error_signature
+{
+  typedef Signature type;
+};
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename R, typename... Args>
+struct redirect_error_signature<R(asio::error_code, Args...)>
+{
+  typedef R type(Args...);
+};
+
+template <typename R, typename... Args>
+struct redirect_error_signature<R(const asio::error_code&, Args...)>
+{
+  typedef R type(Args...);
+};
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename R>
+struct redirect_error_signature<R(asio::error_code)>
+{
+  typedef R type();
+};
+
+template <typename R>
+struct redirect_error_signature<R(const asio::error_code&)>
+{
+  typedef R type();
+};
+
+#define ASIO_PRIVATE_REDIRECT_ERROR_DEF(n) \
+  template <typename R, ASIO_VARIADIC_TPARAMS(n)> \
+  struct redirect_error_signature< \
+      R(asio::error_code, ASIO_VARIADIC_TARGS(n))> \
+  { \
+    typedef R type(ASIO_VARIADIC_TARGS(n)); \
+  }; \
+  \
+  template <typename R, ASIO_VARIADIC_TPARAMS(n)> \
+  struct redirect_error_signature< \
+      R(const asio::error_code&, ASIO_VARIADIC_TARGS(n))> \
+  { \
+    typedef R type(ASIO_VARIADIC_TARGS(n)); \
+  }; \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_REDIRECT_ERROR_DEF)
+#undef ASIO_PRIVATE_REDIRECT_ERROR_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+} // namespace detail
+} // namespace experimental
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename CompletionToken, typename Signature>
+struct async_result<experimental::redirect_error_t<CompletionToken>, Signature>
+  : async_result<CompletionToken,
+      typename experimental::detail::redirect_error_signature<Signature>::type>
+{
+  typedef experimental::detail::redirect_error_handler<
+    typename async_result<CompletionToken,
+      typename experimental::detail::redirect_error_signature<Signature>::type>
+        ::completion_handler_type> completion_handler_type;
+
+  explicit async_result(completion_handler_type& h)
+    : async_result<CompletionToken,
+        typename experimental::detail::redirect_error_signature<
+          Signature>::type>(h.handler_)
+  {
+  }
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+template <typename CompletionToken, typename Signature>
+struct handler_type<experimental::redirect_error_t<CompletionToken>, Signature>
+{
+  typedef experimental::detail::redirect_error_handler<
+    typename async_result<CompletionToken,
+      typename experimental::detail::redirect_error_signature<Signature>::type>
+        ::completion_handler_type> type;
+};
+
+template <typename Handler>
+struct async_result<experimental::detail::redirect_error_handler<Handler> >
+  : async_result<Handler>
+{
+  explicit async_result(
+      experimental::detail::redirect_error_handler<Handler>& h)
+    : async_result<Handler>(h.handler_)
+  {
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Handler, typename Executor>
+struct associated_executor<
+    experimental::detail::redirect_error_handler<Handler>, Executor>
+{
+  typedef typename associated_executor<Handler, Executor>::type type;
+
+  static type get(
+      const experimental::detail::redirect_error_handler<Handler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<Handler, Executor>::get(h.handler_, ex);
+  }
+};
+
+template <typename Handler, typename Allocator>
+struct associated_allocator<
+    experimental::detail::redirect_error_handler<Handler>, Allocator>
+{
+  typedef typename associated_allocator<Handler, Allocator>::type type;
+
+  static type get(
+      const experimental::detail::redirect_error_handler<Handler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<Handler, Allocator>::get(h.handler_, a);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_EXPERIMENTAL_IMPL_REDIRECT_ERROR_HPP
diff --git a/subprojects/asio/include/asio/experimental/redirect_error.hpp b/subprojects/asio/include/asio/experimental/redirect_error.hpp
new file mode 100644
index 000000000..30e81cf5a
--- /dev/null
+++ b/subprojects/asio/include/asio/experimental/redirect_error.hpp
@@ -0,0 +1,67 @@
+//
+// experimental/redirect_error.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_EXPERIMENTAL_REDIRECT_ERROR_HPP
+#define ASIO_EXPERIMENTAL_REDIRECT_ERROR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error_code.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+
+/// Completion token type used to specify that an error produced by an
+/// asynchronous operation is captured to an error_code variable.
+/**
+ * The redirect_error_t class is used to indicate that any error_code produced
+ * by an asynchronous operation is captured to a specified variable.
+ */
+template <typename CompletionToken>
+class redirect_error_t
+{
+public:
+  /// Constructor. 
+  template <typename T>
+  redirect_error_t(ASIO_MOVE_ARG(T) completion_token,
+      asio::error_code& ec)
+    : token_(ASIO_MOVE_CAST(T)(completion_token)),
+      ec_(ec)
+  {
+  }
+
+//private:
+  CompletionToken token_;
+  asio::error_code& ec_;
+};
+
+/// Create a completion token to capture error_code values to a variable.
+template <typename CompletionToken>
+inline redirect_error_t<typename decay<CompletionToken>::type> redirect_error(
+    CompletionToken&& completion_token, asio::error_code& ec)
+{
+  return redirect_error_t<typename decay<CompletionToken>::type>(
+      ASIO_MOVE_CAST(CompletionToken)(completion_token), ec);
+}
+
+} // namespace experimental
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/experimental/impl/redirect_error.hpp"
+
+#endif // ASIO_EXPERIMENTAL_REDIRECT_ERROR_HPP
diff --git a/subprojects/asio/include/asio/generic/basic_endpoint.hpp b/subprojects/asio/include/asio/generic/basic_endpoint.hpp
new file mode 100644
index 000000000..73aa151d6
--- /dev/null
+++ b/subprojects/asio/include/asio/generic/basic_endpoint.hpp
@@ -0,0 +1,193 @@
+//
+// generic/basic_endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_GENERIC_BASIC_ENDPOINT_HPP
+#define ASIO_GENERIC_BASIC_ENDPOINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/generic/detail/endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace generic {
+
+/// Describes an endpoint for any socket type.
+/**
+ * The asio::generic::basic_endpoint class template describes an endpoint
+ * that may be associated with any socket type.
+ *
+ * @note The socket types sockaddr type must be able to fit into a
+ * @c sockaddr_storage structure.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * Endpoint.
+ */
+template <typename Protocol>
+class basic_endpoint
+{
+public:
+  /// The protocol type associated with the endpoint.
+  typedef Protocol protocol_type;
+
+  /// The type of the endpoint structure. This type is dependent on the
+  /// underlying implementation of the socket layer.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined data_type;
+#else
+  typedef asio::detail::socket_addr_type data_type;
+#endif
+
+  /// Default constructor.
+  basic_endpoint()
+  {
+  }
+
+  /// Construct an endpoint from the specified socket address.
+  basic_endpoint(const void* socket_address,
+      std::size_t socket_address_size, int socket_protocol = 0)
+    : impl_(socket_address, socket_address_size, socket_protocol)
+  {
+  }
+
+  /// Construct an endpoint from the specific endpoint type.
+  template <typename Endpoint>
+  basic_endpoint(const Endpoint& endpoint)
+    : impl_(endpoint.data(), endpoint.size(), endpoint.protocol().protocol())
+  {
+  }
+
+  /// Copy constructor.
+  basic_endpoint(const basic_endpoint& other)
+    : impl_(other.impl_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  basic_endpoint(basic_endpoint&& other)
+    : impl_(other.impl_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from another endpoint.
+  basic_endpoint& operator=(const basic_endpoint& other)
+  {
+    impl_ = other.impl_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move-assign from another endpoint.
+  basic_endpoint& operator=(basic_endpoint&& other)
+  {
+    impl_ = other.impl_;
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// The protocol associated with the endpoint.
+  protocol_type protocol() const
+  {
+    return protocol_type(impl_.family(), impl_.protocol());
+  }
+
+  /// Get the underlying endpoint in the native type.
+  data_type* data()
+  {
+    return impl_.data();
+  }
+
+  /// Get the underlying endpoint in the native type.
+  const data_type* data() const
+  {
+    return impl_.data();
+  }
+
+  /// Get the underlying size of the endpoint in the native type.
+  std::size_t size() const
+  {
+    return impl_.size();
+  }
+
+  /// Set the underlying size of the endpoint in the native type.
+  void resize(std::size_t new_size)
+  {
+    impl_.resize(new_size);
+  }
+
+  /// Get the capacity of the endpoint in the native type.
+  std::size_t capacity() const
+  {
+    return impl_.capacity();
+  }
+
+  /// Compare two endpoints for equality.
+  friend bool operator==(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return e1.impl_ == e2.impl_;
+  }
+
+  /// Compare two endpoints for inequality.
+  friend bool operator!=(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return !(e1.impl_ == e2.impl_);
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator<(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return e1.impl_ < e2.impl_;
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator>(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return e2.impl_ < e1.impl_;
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator<=(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return !(e2 < e1);
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator>=(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return !(e1 < e2);
+  }
+
+private:
+  // The underlying generic endpoint.
+  asio::generic::detail::endpoint impl_;
+};
+
+} // namespace generic
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_GENERIC_BASIC_ENDPOINT_HPP
diff --git a/subprojects/asio/include/asio/generic/datagram_protocol.hpp b/subprojects/asio/include/asio/generic/datagram_protocol.hpp
new file mode 100644
index 000000000..8678ad85b
--- /dev/null
+++ b/subprojects/asio/include/asio/generic/datagram_protocol.hpp
@@ -0,0 +1,123 @@
+//
+// generic/datagram_protocol.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_GENERIC_DATAGRAM_PROTOCOL_HPP
+#define ASIO_GENERIC_DATAGRAM_PROTOCOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <typeinfo>
+#include "asio/basic_datagram_socket.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/generic/basic_endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace generic {
+
+/// Encapsulates the flags needed for a generic datagram-oriented socket.
+/**
+ * The asio::generic::datagram_protocol class contains flags necessary
+ * for datagram-oriented sockets of any address family and protocol.
+ *
+ * @par Examples
+ * Constructing using a native address family and socket protocol:
+ * @code datagram_protocol p(AF_INET, IPPROTO_UDP); @endcode
+ * Constructing from a specific protocol type:
+ * @code datagram_protocol p(asio::ip::udp::v4()); @endcode
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol.
+ */
+class datagram_protocol
+{
+public:
+  /// Construct a protocol object for a specific address family and protocol.
+  datagram_protocol(int address_family, int socket_protocol)
+    : family_(address_family),
+      protocol_(socket_protocol)
+  {
+  }
+
+  /// Construct a generic protocol object from a specific protocol.
+  /**
+   * @throws @c bad_cast Thrown if the source protocol is not datagram-oriented.
+   */
+  template <typename Protocol>
+  datagram_protocol(const Protocol& source_protocol)
+    : family_(source_protocol.family()),
+      protocol_(source_protocol.protocol())
+  {
+    if (source_protocol.type() != type())
+    {
+      std::bad_cast ex;
+      asio::detail::throw_exception(ex);
+    }
+  }
+
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return ASIO_OS_DEF(SOCK_DGRAM);
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return protocol_;
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return family_;
+  }
+
+  /// Compare two protocols for equality.
+  friend bool operator==(const datagram_protocol& p1,
+      const datagram_protocol& p2)
+  {
+    return p1.family_ == p2.family_ && p1.protocol_ == p2.protocol_;
+  }
+
+  /// Compare two protocols for inequality.
+  friend bool operator!=(const datagram_protocol& p1,
+      const datagram_protocol& p2)
+  {
+    return !(p1 == p2);
+  }
+
+  /// The type of an endpoint.
+  typedef basic_endpoint<datagram_protocol> endpoint;
+
+  /// The generic socket type.
+  typedef basic_datagram_socket<datagram_protocol> socket;
+
+private:
+  int family_;
+  int protocol_;
+};
+
+} // namespace generic
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_GENERIC_DATAGRAM_PROTOCOL_HPP
diff --git a/subprojects/asio/include/asio/generic/detail/endpoint.hpp b/subprojects/asio/include/asio/generic/detail/endpoint.hpp
new file mode 100644
index 000000000..190beb14c
--- /dev/null
+++ b/subprojects/asio/include/asio/generic/detail/endpoint.hpp
@@ -0,0 +1,133 @@
+//
+// generic/detail/endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_GENERIC_DETAIL_ENDPOINT_HPP
+#define ASIO_GENERIC_DETAIL_ENDPOINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cstddef>
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace generic {
+namespace detail {
+
+// Helper class for implementing a generic socket endpoint.
+class endpoint
+{
+public:
+  // Default constructor.
+  ASIO_DECL endpoint();
+
+  // Construct an endpoint from the specified raw bytes.
+  ASIO_DECL endpoint(const void* sock_addr,
+      std::size_t sock_addr_size, int sock_protocol);
+
+  // Copy constructor.
+  endpoint(const endpoint& other)
+    : data_(other.data_),
+      size_(other.size_),
+      protocol_(other.protocol_)
+  {
+  }
+
+  // Assign from another endpoint.
+  endpoint& operator=(const endpoint& other)
+  {
+    data_ = other.data_;
+    size_ = other.size_;
+    protocol_ = other.protocol_;
+    return *this;
+  }
+
+  // Get the address family associated with the endpoint.
+  int family() const
+  {
+    return data_.base.sa_family;
+  }
+
+  // Get the socket protocol associated with the endpoint.
+  int protocol() const
+  {
+    return protocol_;
+  }
+
+  // Get the underlying endpoint in the native type.
+  asio::detail::socket_addr_type* data()
+  {
+    return &data_.base;
+  }
+
+  // Get the underlying endpoint in the native type.
+  const asio::detail::socket_addr_type* data() const
+  {
+    return &data_.base;
+  }
+
+  // Get the underlying size of the endpoint in the native type.
+  std::size_t size() const
+  {
+    return size_;
+  }
+
+  // Set the underlying size of the endpoint in the native type.
+  ASIO_DECL void resize(std::size_t size);
+
+  // Get the capacity of the endpoint in the native type.
+  std::size_t capacity() const
+  {
+    return sizeof(asio::detail::sockaddr_storage_type);
+  }
+
+  // Compare two endpoints for equality.
+  ASIO_DECL friend bool operator==(
+      const endpoint& e1, const endpoint& e2);
+
+  // Compare endpoints for ordering.
+  ASIO_DECL friend bool operator<(
+      const endpoint& e1, const endpoint& e2);
+
+private:
+  // The underlying socket address.
+  union data_union
+  {
+    asio::detail::socket_addr_type base;
+    asio::detail::sockaddr_storage_type generic;
+  } data_;
+
+  // The length of the socket address stored in the endpoint.
+  std::size_t size_;
+
+  // The socket protocol associated with the endpoint.
+  int protocol_;
+
+  // Initialise with a specified memory.
+  ASIO_DECL void init(const void* sock_addr,
+      std::size_t sock_addr_size, int sock_protocol);
+};
+
+} // namespace detail
+} // namespace generic
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/generic/detail/impl/endpoint.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_GENERIC_DETAIL_ENDPOINT_HPP
diff --git a/subprojects/asio/include/asio/generic/detail/impl/endpoint.ipp b/subprojects/asio/include/asio/generic/detail/impl/endpoint.ipp
new file mode 100644
index 000000000..227ffe1e3
--- /dev/null
+++ b/subprojects/asio/include/asio/generic/detail/impl/endpoint.ipp
@@ -0,0 +1,110 @@
+//
+// generic/detail/impl/endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_GENERIC_DETAIL_IMPL_ENDPOINT_IPP
+#define ASIO_GENERIC_DETAIL_IMPL_ENDPOINT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cstring>
+#include <typeinfo>
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/error.hpp"
+#include "asio/generic/detail/endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace generic {
+namespace detail {
+
+endpoint::endpoint()
+{
+  init(0, 0, 0);
+}
+
+endpoint::endpoint(const void* sock_addr,
+    std::size_t sock_addr_size, int sock_protocol)
+{
+  init(sock_addr, sock_addr_size, sock_protocol);
+}
+
+void endpoint::resize(std::size_t new_size)
+{
+  if (new_size > sizeof(asio::detail::sockaddr_storage_type))
+  {
+    asio::error_code ec(asio::error::invalid_argument);
+    asio::detail::throw_error(ec);
+  }
+  else
+  {
+    size_ = new_size;
+    protocol_ = 0;
+  }
+}
+
+bool operator==(const endpoint& e1, const endpoint& e2)
+{
+  using namespace std; // For memcmp.
+  return e1.size() == e2.size() && memcmp(e1.data(), e2.data(), e1.size()) == 0;
+}
+
+bool operator<(const endpoint& e1, const endpoint& e2)
+{
+  if (e1.protocol() < e2.protocol())
+    return true;
+
+  if (e1.protocol() > e2.protocol())
+    return false;
+
+  using namespace std; // For memcmp.
+  std::size_t compare_size = e1.size() < e2.size() ? e1.size() : e2.size();
+  int compare_result = memcmp(e1.data(), e2.data(), compare_size);
+
+  if (compare_result < 0)
+    return true;
+
+  if (compare_result > 0)
+    return false;
+
+  return e1.size() < e2.size();
+}
+
+void endpoint::init(const void* sock_addr,
+    std::size_t sock_addr_size, int sock_protocol)
+{
+  if (sock_addr_size > sizeof(asio::detail::sockaddr_storage_type))
+  {
+    asio::error_code ec(asio::error::invalid_argument);
+    asio::detail::throw_error(ec);
+  }
+
+  using namespace std; // For memset and memcpy.
+  memset(&data_.generic, 0, sizeof(asio::detail::sockaddr_storage_type));
+  if (sock_addr_size > 0)
+    memcpy(&data_.generic, sock_addr, sock_addr_size);
+
+  size_ = sock_addr_size;
+  protocol_ = sock_protocol;
+}
+
+} // namespace detail
+} // namespace generic
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_GENERIC_DETAIL_IMPL_ENDPOINT_IPP
diff --git a/subprojects/asio/include/asio/generic/raw_protocol.hpp b/subprojects/asio/include/asio/generic/raw_protocol.hpp
new file mode 100644
index 000000000..b83dca6e3
--- /dev/null
+++ b/subprojects/asio/include/asio/generic/raw_protocol.hpp
@@ -0,0 +1,121 @@
+//
+// generic/raw_protocol.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_GENERIC_RAW_PROTOCOL_HPP
+#define ASIO_GENERIC_RAW_PROTOCOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <typeinfo>
+#include "asio/basic_raw_socket.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/generic/basic_endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace generic {
+
+/// Encapsulates the flags needed for a generic raw socket.
+/**
+ * The asio::generic::raw_protocol class contains flags necessary for
+ * raw sockets of any address family and protocol.
+ *
+ * @par Examples
+ * Constructing using a native address family and socket protocol:
+ * @code raw_protocol p(AF_INET, IPPROTO_ICMP); @endcode
+ * Constructing from a specific protocol type:
+ * @code raw_protocol p(asio::ip::icmp::v4()); @endcode
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol.
+ */
+class raw_protocol
+{
+public:
+  /// Construct a protocol object for a specific address family and protocol.
+  raw_protocol(int address_family, int socket_protocol)
+    : family_(address_family),
+      protocol_(socket_protocol)
+  {
+  }
+
+  /// Construct a generic protocol object from a specific protocol.
+  /**
+   * @throws @c bad_cast Thrown if the source protocol is not raw-oriented.
+   */
+  template <typename Protocol>
+  raw_protocol(const Protocol& source_protocol)
+    : family_(source_protocol.family()),
+      protocol_(source_protocol.protocol())
+  {
+    if (source_protocol.type() != type())
+    {
+      std::bad_cast ex;
+      asio::detail::throw_exception(ex);
+    }
+  }
+
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return ASIO_OS_DEF(SOCK_RAW);
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return protocol_;
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return family_;
+  }
+
+  /// Compare two protocols for equality.
+  friend bool operator==(const raw_protocol& p1, const raw_protocol& p2)
+  {
+    return p1.family_ == p2.family_ && p1.protocol_ == p2.protocol_;
+  }
+
+  /// Compare two protocols for inequality.
+  friend bool operator!=(const raw_protocol& p1, const raw_protocol& p2)
+  {
+    return !(p1 == p2);
+  }
+
+  /// The type of an endpoint.
+  typedef basic_endpoint<raw_protocol> endpoint;
+
+  /// The generic socket type.
+  typedef basic_raw_socket<raw_protocol> socket;
+
+private:
+  int family_;
+  int protocol_;
+};
+
+} // namespace generic
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_GENERIC_RAW_PROTOCOL_HPP
diff --git a/subprojects/asio/include/asio/generic/seq_packet_protocol.hpp b/subprojects/asio/include/asio/generic/seq_packet_protocol.hpp
new file mode 100644
index 000000000..f92a4c8f8
--- /dev/null
+++ b/subprojects/asio/include/asio/generic/seq_packet_protocol.hpp
@@ -0,0 +1,122 @@
+//
+// generic/seq_packet_protocol.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_GENERIC_SEQ_PACKET_PROTOCOL_HPP
+#define ASIO_GENERIC_SEQ_PACKET_PROTOCOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <typeinfo>
+#include "asio/basic_seq_packet_socket.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/generic/basic_endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace generic {
+
+/// Encapsulates the flags needed for a generic sequenced packet socket.
+/**
+ * The asio::generic::seq_packet_protocol class contains flags necessary
+ * for seq_packet-oriented sockets of any address family and protocol.
+ *
+ * @par Examples
+ * Constructing using a native address family and socket protocol:
+ * @code seq_packet_protocol p(AF_INET, IPPROTO_SCTP); @endcode
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol.
+ */
+class seq_packet_protocol
+{
+public:
+  /// Construct a protocol object for a specific address family and protocol.
+  seq_packet_protocol(int address_family, int socket_protocol)
+    : family_(address_family),
+      protocol_(socket_protocol)
+  {
+  }
+
+  /// Construct a generic protocol object from a specific protocol.
+  /**
+   * @throws @c bad_cast Thrown if the source protocol is not based around
+   * sequenced packets.
+   */
+  template <typename Protocol>
+  seq_packet_protocol(const Protocol& source_protocol)
+    : family_(source_protocol.family()),
+      protocol_(source_protocol.protocol())
+  {
+    if (source_protocol.type() != type())
+    {
+      std::bad_cast ex;
+      asio::detail::throw_exception(ex);
+    }
+  }
+
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return ASIO_OS_DEF(SOCK_SEQPACKET);
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return protocol_;
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return family_;
+  }
+
+  /// Compare two protocols for equality.
+  friend bool operator==(const seq_packet_protocol& p1,
+      const seq_packet_protocol& p2)
+  {
+    return p1.family_ == p2.family_ && p1.protocol_ == p2.protocol_;
+  }
+
+  /// Compare two protocols for inequality.
+  friend bool operator!=(const seq_packet_protocol& p1,
+      const seq_packet_protocol& p2)
+  {
+    return !(p1 == p2);
+  }
+
+  /// The type of an endpoint.
+  typedef basic_endpoint<seq_packet_protocol> endpoint;
+
+  /// The generic socket type.
+  typedef basic_seq_packet_socket<seq_packet_protocol> socket;
+
+private:
+  int family_;
+  int protocol_;
+};
+
+} // namespace generic
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_GENERIC_SEQ_PACKET_PROTOCOL_HPP
diff --git a/subprojects/asio/include/asio/generic/stream_protocol.hpp b/subprojects/asio/include/asio/generic/stream_protocol.hpp
new file mode 100644
index 000000000..8349f25bc
--- /dev/null
+++ b/subprojects/asio/include/asio/generic/stream_protocol.hpp
@@ -0,0 +1,127 @@
+//
+// generic/stream_protocol.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_GENERIC_STREAM_PROTOCOL_HPP
+#define ASIO_GENERIC_STREAM_PROTOCOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <typeinfo>
+#include "asio/basic_socket_iostream.hpp"
+#include "asio/basic_stream_socket.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/generic/basic_endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace generic {
+
+/// Encapsulates the flags needed for a generic stream-oriented socket.
+/**
+ * The asio::generic::stream_protocol class contains flags necessary for
+ * stream-oriented sockets of any address family and protocol.
+ *
+ * @par Examples
+ * Constructing using a native address family and socket protocol:
+ * @code stream_protocol p(AF_INET, IPPROTO_TCP); @endcode
+ * Constructing from a specific protocol type:
+ * @code stream_protocol p(asio::ip::tcp::v4()); @endcode
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol.
+ */
+class stream_protocol
+{
+public:
+  /// Construct a protocol object for a specific address family and protocol.
+  stream_protocol(int address_family, int socket_protocol)
+    : family_(address_family),
+      protocol_(socket_protocol)
+  {
+  }
+
+  /// Construct a generic protocol object from a specific protocol.
+  /**
+   * @throws @c bad_cast Thrown if the source protocol is not stream-oriented.
+   */
+  template <typename Protocol>
+  stream_protocol(const Protocol& source_protocol)
+    : family_(source_protocol.family()),
+      protocol_(source_protocol.protocol())
+  {
+    if (source_protocol.type() != type())
+    {
+      std::bad_cast ex;
+      asio::detail::throw_exception(ex);
+    }
+  }
+
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return ASIO_OS_DEF(SOCK_STREAM);
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return protocol_;
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return family_;
+  }
+
+  /// Compare two protocols for equality.
+  friend bool operator==(const stream_protocol& p1, const stream_protocol& p2)
+  {
+    return p1.family_ == p2.family_ && p1.protocol_ == p2.protocol_;
+  }
+
+  /// Compare two protocols for inequality.
+  friend bool operator!=(const stream_protocol& p1, const stream_protocol& p2)
+  {
+    return !(p1 == p2);
+  }
+
+  /// The type of an endpoint.
+  typedef basic_endpoint<stream_protocol> endpoint;
+
+  /// The generic socket type.
+  typedef basic_stream_socket<stream_protocol> socket;
+
+#if !defined(ASIO_NO_IOSTREAM)
+  /// The generic socket iostream type.
+  typedef basic_socket_iostream<stream_protocol> iostream;
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+private:
+  int family_;
+  int protocol_;
+};
+
+} // namespace generic
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_GENERIC_STREAM_PROTOCOL_HPP
diff --git a/subprojects/asio/include/asio/handler_alloc_hook.hpp b/subprojects/asio/include/asio/handler_alloc_hook.hpp
new file mode 100644
index 000000000..d7fe2b01f
--- /dev/null
+++ b/subprojects/asio/include/asio/handler_alloc_hook.hpp
@@ -0,0 +1,81 @@
+//
+// handler_alloc_hook.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_HANDLER_ALLOC_HOOK_HPP
+#define ASIO_HANDLER_ALLOC_HOOK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default allocation function for handlers.
+/**
+ * Asynchronous operations may need to allocate temporary objects. Since
+ * asynchronous operations have a handler function object, these temporary
+ * objects can be said to be associated with the handler.
+ *
+ * Implement asio_handler_allocate and asio_handler_deallocate for your own
+ * handlers to provide custom allocation for these temporary objects.
+ *
+ * The default implementation of these allocation hooks uses <tt>::operator
+ * new</tt> and <tt>::operator delete</tt>.
+ *
+ * @note All temporary objects associated with a handler will be deallocated
+ * before the upcall to the handler is performed. This allows the same memory to
+ * be reused for a subsequent asynchronous operation initiated by the handler.
+ *
+ * @par Example
+ * @code
+ * class my_handler;
+ *
+ * void* asio_handler_allocate(std::size_t size, my_handler* context)
+ * {
+ *   return ::operator new(size);
+ * }
+ *
+ * void asio_handler_deallocate(void* pointer, std::size_t size,
+ *     my_handler* context)
+ * {
+ *   ::operator delete(pointer);
+ * }
+ * @endcode
+ */
+ASIO_DECL void* asio_handler_allocate(
+    std::size_t size, ...);
+
+/// Default deallocation function for handlers.
+/**
+ * Implement asio_handler_allocate and asio_handler_deallocate for your own
+ * handlers to provide custom allocation for the associated temporary objects.
+ *
+ * The default implementation of these allocation hooks uses <tt>::operator
+ * new</tt> and <tt>::operator delete</tt>.
+ *
+ * @sa asio_handler_allocate.
+ */
+ASIO_DECL void asio_handler_deallocate(
+    void* pointer, std::size_t size, ...);
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/handler_alloc_hook.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_HANDLER_ALLOC_HOOK_HPP
diff --git a/subprojects/asio/include/asio/handler_continuation_hook.hpp b/subprojects/asio/include/asio/handler_continuation_hook.hpp
new file mode 100644
index 000000000..d41d10595
--- /dev/null
+++ b/subprojects/asio/include/asio/handler_continuation_hook.hpp
@@ -0,0 +1,54 @@
+//
+// handler_continuation_hook.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_HANDLER_CONTINUATION_HOOK_HPP
+#define ASIO_HANDLER_CONTINUATION_HOOK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default continuation function for handlers.
+/**
+ * Asynchronous operations may represent a continuation of the asynchronous
+ * control flow associated with the current handler. The implementation can use
+ * this knowledge to optimise scheduling of the handler.
+ *
+ * Implement asio_handler_is_continuation for your own handlers to indicate
+ * when a handler represents a continuation.
+ *
+ * The default implementation of the continuation hook returns <tt>false</tt>.
+ *
+ * @par Example
+ * @code
+ * class my_handler;
+ *
+ * bool asio_handler_is_continuation(my_handler* context)
+ * {
+ *   return true;
+ * }
+ * @endcode
+ */
+inline bool asio_handler_is_continuation(...)
+{
+  return false;
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_HANDLER_CONTINUATION_HOOK_HPP
diff --git a/subprojects/asio/include/asio/handler_invoke_hook.hpp b/subprojects/asio/include/asio/handler_invoke_hook.hpp
new file mode 100644
index 000000000..ee618e5ef
--- /dev/null
+++ b/subprojects/asio/include/asio/handler_invoke_hook.hpp
@@ -0,0 +1,85 @@
+//
+// handler_invoke_hook.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_HANDLER_INVOKE_HOOK_HPP
+#define ASIO_HANDLER_INVOKE_HOOK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/** @defgroup asio_handler_invoke asio::asio_handler_invoke
+ *
+ * @brief Default invoke function for handlers.
+ *
+ * Completion handlers for asynchronous operations are invoked by the
+ * io_context associated with the corresponding object (e.g. a socket or
+ * deadline_timer). Certain guarantees are made on when the handler may be
+ * invoked, in particular that a handler can only be invoked from a thread that
+ * is currently calling @c run() on the corresponding io_context object.
+ * Handlers may subsequently be invoked through other objects (such as
+ * io_context::strand objects) that provide additional guarantees.
+ *
+ * When asynchronous operations are composed from other asynchronous
+ * operations, all intermediate handlers should be invoked using the same
+ * method as the final handler. This is required to ensure that user-defined
+ * objects are not accessed in a way that may violate the guarantees. This
+ * hooking function ensures that the invoked method used for the final handler
+ * is accessible at each intermediate step.
+ *
+ * Implement asio_handler_invoke for your own handlers to specify a custom
+ * invocation strategy.
+ *
+ * This default implementation invokes the function object like so:
+ * @code function(); @endcode
+ * If necessary, the default implementation makes a copy of the function object
+ * so that the non-const operator() can be used.
+ *
+ * @par Example
+ * @code
+ * class my_handler;
+ *
+ * template <typename Function>
+ * void asio_handler_invoke(Function function, my_handler* context)
+ * {
+ *   context->strand_.dispatch(function);
+ * }
+ * @endcode
+ */
+/*@{*/
+
+/// Default handler invocation hook used for non-const function objects.
+template <typename Function>
+inline void asio_handler_invoke(Function& function, ...)
+{
+  function();
+}
+
+/// Default handler invocation hook used for const function objects.
+template <typename Function>
+inline void asio_handler_invoke(const Function& function, ...)
+{
+  Function tmp(function);
+  tmp();
+}
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_HANDLER_INVOKE_HOOK_HPP
diff --git a/subprojects/asio/include/asio/handler_type.hpp b/subprojects/asio/include/asio/handler_type.hpp
new file mode 100644
index 000000000..bc0d30514
--- /dev/null
+++ b/subprojects/asio/include/asio/handler_type.hpp
@@ -0,0 +1,50 @@
+//
+// handler_type.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_HANDLER_TYPE_HPP
+#define ASIO_HANDLER_TYPE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// (Deprecated: Use two-parameter version of async_result.) Default handler
+/// type traits provided for all completion token types.
+/**
+ * The handler_type traits class is used for determining the concrete handler
+ * type to be used for an asynchronous operation. It allows the handler type to
+ * be determined at the point where the specific completion handler signature
+ * is known.
+ *
+ * This template may be specialised for user-defined completion token types.
+ */
+template <typename CompletionToken, typename Signature, typename = void>
+struct handler_type
+{
+  /// The handler type for the specific signature.
+  typedef typename conditional<
+    is_same<CompletionToken, typename decay<CompletionToken>::type>::value,
+    decay<CompletionToken>,
+    handler_type<typename decay<CompletionToken>::type, Signature>
+  >::type::type type;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_HANDLER_TYPE_HPP
diff --git a/subprojects/asio/include/asio/high_resolution_timer.hpp b/subprojects/asio/include/asio/high_resolution_timer.hpp
new file mode 100644
index 000000000..0549cc256
--- /dev/null
+++ b/subprojects/asio/include/asio/high_resolution_timer.hpp
@@ -0,0 +1,44 @@
+//
+// high_resolution_timer.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_HIGH_RESOLUTION_TIMER_HPP
+#define ASIO_HIGH_RESOLUTION_TIMER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_waitable_timer.hpp"
+#include "asio/detail/chrono.hpp"
+
+namespace asio {
+
+/// Typedef for a timer based on the high resolution clock.
+/**
+ * This typedef uses the C++11 @c &lt;chrono&gt; standard library facility, if
+ * available. Otherwise, it may use the Boost.Chrono library. To explicitly
+ * utilise Boost.Chrono, use the basic_waitable_timer template directly:
+ * @code
+ * typedef basic_waitable_timer<boost::chrono::high_resolution_clock> timer;
+ * @endcode
+ */
+typedef basic_waitable_timer<
+    chrono::high_resolution_clock>
+  high_resolution_timer;
+
+} // namespace asio
+
+#endif // defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_HIGH_RESOLUTION_TIMER_HPP
diff --git a/subprojects/asio/include/asio/impl/buffered_read_stream.hpp b/subprojects/asio/include/asio/impl/buffered_read_stream.hpp
new file mode 100644
index 000000000..e0ed20e4c
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/buffered_read_stream.hpp
@@ -0,0 +1,429 @@
+//
+// impl/buffered_read_stream.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_BUFFERED_READ_STREAM_HPP
+#define ASIO_IMPL_BUFFERED_READ_STREAM_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename Stream>
+std::size_t buffered_read_stream<Stream>::fill()
+{
+  detail::buffer_resize_guard<detail::buffered_stream_storage>
+    resize_guard(storage_);
+  std::size_t previous_size = storage_.size();
+  storage_.resize(storage_.capacity());
+  storage_.resize(previous_size + next_layer_.read_some(buffer(
+          storage_.data() + previous_size,
+          storage_.size() - previous_size)));
+  resize_guard.commit();
+  return storage_.size() - previous_size;
+}
+
+template <typename Stream>
+std::size_t buffered_read_stream<Stream>::fill(asio::error_code& ec)
+{
+  detail::buffer_resize_guard<detail::buffered_stream_storage>
+    resize_guard(storage_);
+  std::size_t previous_size = storage_.size();
+  storage_.resize(storage_.capacity());
+  storage_.resize(previous_size + next_layer_.read_some(buffer(
+          storage_.data() + previous_size,
+          storage_.size() - previous_size),
+        ec));
+  resize_guard.commit();
+  return storage_.size() - previous_size;
+}
+
+namespace detail
+{
+  template <typename ReadHandler>
+  class buffered_fill_handler
+  {
+  public:
+    buffered_fill_handler(detail::buffered_stream_storage& storage,
+        std::size_t previous_size, ReadHandler& handler)
+      : storage_(storage),
+        previous_size_(previous_size),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    buffered_fill_handler(const buffered_fill_handler& other)
+      : storage_(other.storage_),
+        previous_size_(other.previous_size_),
+        handler_(other.handler_)
+    {
+    }
+
+    buffered_fill_handler(buffered_fill_handler&& other)
+      : storage_(other.storage_),
+        previous_size_(other.previous_size_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        const std::size_t bytes_transferred)
+    {
+      storage_.resize(previous_size_ + bytes_transferred);
+      handler_(ec, bytes_transferred);
+    }
+
+  //private:
+    detail::buffered_stream_storage& storage_;
+    std::size_t previous_size_;
+    ReadHandler handler_;
+  };
+
+  template <typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      buffered_fill_handler<ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      buffered_fill_handler<ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      buffered_fill_handler<ReadHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      buffered_fill_handler<ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      buffered_fill_handler<ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::buffered_fill_handler<ReadHandler>, Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(const detail::buffered_fill_handler<ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::buffered_fill_handler<ReadHandler>, Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(const detail::buffered_fill_handler<ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename Stream>
+template <typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+buffered_read_stream<Stream>::async_fill(
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  std::size_t previous_size = storage_.size();
+  storage_.resize(storage_.capacity());
+  next_layer_.async_read_some(
+      buffer(
+        storage_.data() + previous_size,
+        storage_.size() - previous_size),
+      detail::buffered_fill_handler<ASIO_HANDLER_TYPE(
+        ReadHandler, void (asio::error_code, std::size_t))>(
+        storage_, previous_size, init.completion_handler));
+
+  return init.result.get();
+}
+
+template <typename Stream>
+template <typename MutableBufferSequence>
+std::size_t buffered_read_stream<Stream>::read_some(
+    const MutableBufferSequence& buffers)
+{
+  using asio::buffer_size;
+  if (buffer_size(buffers) == 0)
+    return 0;
+
+  if (storage_.empty())
+    this->fill();
+
+  return this->copy(buffers);
+}
+
+template <typename Stream>
+template <typename MutableBufferSequence>
+std::size_t buffered_read_stream<Stream>::read_some(
+    const MutableBufferSequence& buffers, asio::error_code& ec)
+{
+  ec = asio::error_code();
+
+  using asio::buffer_size;
+  if (buffer_size(buffers) == 0)
+    return 0;
+
+  if (storage_.empty() && !this->fill(ec))
+    return 0;
+
+  return this->copy(buffers);
+}
+
+namespace detail
+{
+  template <typename MutableBufferSequence, typename ReadHandler>
+  class buffered_read_some_handler
+  {
+  public:
+    buffered_read_some_handler(detail::buffered_stream_storage& storage,
+        const MutableBufferSequence& buffers, ReadHandler& handler)
+      : storage_(storage),
+        buffers_(buffers),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+      buffered_read_some_handler(const buffered_read_some_handler& other)
+        : storage_(other.storage_),
+          buffers_(other.buffers_),
+          handler_(other.handler_)
+      {
+      }
+
+      buffered_read_some_handler(buffered_read_some_handler&& other)
+        : storage_(other.storage_),
+          buffers_(other.buffers_),
+          handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+      {
+      }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec, std::size_t)
+    {
+      if (ec || storage_.empty())
+      {
+        const std::size_t length = 0;
+        handler_(ec, length);
+      }
+      else
+      {
+        const std::size_t bytes_copied = asio::buffer_copy(
+            buffers_, storage_.data(), storage_.size());
+        storage_.consume(bytes_copied);
+        handler_(ec, bytes_copied);
+      }
+    }
+
+  //private:
+    detail::buffered_stream_storage& storage_;
+    MutableBufferSequence buffers_;
+    ReadHandler handler_;
+  };
+
+  template <typename MutableBufferSequence, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      buffered_read_some_handler<
+        MutableBufferSequence, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename MutableBufferSequence, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      buffered_read_some_handler<
+        MutableBufferSequence, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename MutableBufferSequence, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      buffered_read_some_handler<
+        MutableBufferSequence, ReadHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename MutableBufferSequence,
+      typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      buffered_read_some_handler<
+        MutableBufferSequence, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename MutableBufferSequence,
+      typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      buffered_read_some_handler<
+        MutableBufferSequence, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename MutableBufferSequence,
+    typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::buffered_read_some_handler<MutableBufferSequence, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::buffered_read_some_handler<
+        MutableBufferSequence, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename MutableBufferSequence,
+    typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::buffered_read_some_handler<MutableBufferSequence, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::buffered_read_some_handler<
+        MutableBufferSequence, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename Stream>
+template <typename MutableBufferSequence, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+buffered_read_stream<Stream>::async_read_some(
+    const MutableBufferSequence& buffers,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  using asio::buffer_size;
+  if (buffer_size(buffers) == 0 || !storage_.empty())
+  {
+    next_layer_.async_read_some(ASIO_MUTABLE_BUFFER(0, 0),
+        detail::buffered_read_some_handler<
+          MutableBufferSequence, ASIO_HANDLER_TYPE(
+            ReadHandler, void (asio::error_code, std::size_t))>(
+            storage_, buffers, init.completion_handler));
+  }
+  else
+  {
+    this->async_fill(detail::buffered_read_some_handler<
+          MutableBufferSequence, ASIO_HANDLER_TYPE(
+            ReadHandler, void (asio::error_code, std::size_t))>(
+            storage_, buffers, init.completion_handler));
+  }
+
+  return init.result.get();
+}
+
+template <typename Stream>
+template <typename MutableBufferSequence>
+std::size_t buffered_read_stream<Stream>::peek(
+    const MutableBufferSequence& buffers)
+{
+  if (storage_.empty())
+    this->fill();
+  return this->peek_copy(buffers);
+}
+
+template <typename Stream>
+template <typename MutableBufferSequence>
+std::size_t buffered_read_stream<Stream>::peek(
+    const MutableBufferSequence& buffers, asio::error_code& ec)
+{
+  ec = asio::error_code();
+  if (storage_.empty() && !this->fill(ec))
+    return 0;
+  return this->peek_copy(buffers);
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_BUFFERED_READ_STREAM_HPP
diff --git a/subprojects/asio/include/asio/impl/buffered_write_stream.hpp b/subprojects/asio/include/asio/impl/buffered_write_stream.hpp
new file mode 100644
index 000000000..bc2d823ab
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/buffered_write_stream.hpp
@@ -0,0 +1,411 @@
+//
+// impl/buffered_write_stream.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_BUFFERED_WRITE_STREAM_HPP
+#define ASIO_IMPL_BUFFERED_WRITE_STREAM_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename Stream>
+std::size_t buffered_write_stream<Stream>::flush()
+{
+  std::size_t bytes_written = write(next_layer_,
+      buffer(storage_.data(), storage_.size()));
+  storage_.consume(bytes_written);
+  return bytes_written;
+}
+
+template <typename Stream>
+std::size_t buffered_write_stream<Stream>::flush(asio::error_code& ec)
+{
+  std::size_t bytes_written = write(next_layer_,
+      buffer(storage_.data(), storage_.size()),
+      transfer_all(), ec);
+  storage_.consume(bytes_written);
+  return bytes_written;
+}
+
+namespace detail
+{
+  template <typename WriteHandler>
+  class buffered_flush_handler
+  {
+  public:
+    buffered_flush_handler(detail::buffered_stream_storage& storage,
+        WriteHandler& handler)
+      : storage_(storage),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    buffered_flush_handler(const buffered_flush_handler& other)
+      : storage_(other.storage_),
+        handler_(other.handler_)
+    {
+    }
+
+    buffered_flush_handler(buffered_flush_handler&& other)
+      : storage_(other.storage_),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        const std::size_t bytes_written)
+    {
+      storage_.consume(bytes_written);
+      handler_(ec, bytes_written);
+    }
+
+  //private:
+    detail::buffered_stream_storage& storage_;
+    WriteHandler handler_;
+  };
+
+  template <typename WriteHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      buffered_flush_handler<WriteHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename WriteHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      buffered_flush_handler<WriteHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename WriteHandler>
+  inline bool asio_handler_is_continuation(
+      buffered_flush_handler<WriteHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename WriteHandler>
+  inline void asio_handler_invoke(Function& function,
+      buffered_flush_handler<WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename WriteHandler>
+  inline void asio_handler_invoke(const Function& function,
+      buffered_flush_handler<WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename WriteHandler, typename Allocator>
+struct associated_allocator<
+    detail::buffered_flush_handler<WriteHandler>, Allocator>
+{
+  typedef typename associated_allocator<WriteHandler, Allocator>::type type;
+
+  static type get(const detail::buffered_flush_handler<WriteHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<WriteHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename WriteHandler, typename Executor>
+struct associated_executor<
+    detail::buffered_flush_handler<WriteHandler>, Executor>
+{
+  typedef typename associated_executor<WriteHandler, Executor>::type type;
+
+  static type get(const detail::buffered_flush_handler<WriteHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<WriteHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename Stream>
+template <typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+buffered_write_stream<Stream>::async_flush(
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  async_write(next_layer_, buffer(storage_.data(), storage_.size()),
+      detail::buffered_flush_handler<ASIO_HANDLER_TYPE(
+        WriteHandler, void (asio::error_code, std::size_t))>(
+        storage_, init.completion_handler));
+
+  return init.result.get();
+}
+
+template <typename Stream>
+template <typename ConstBufferSequence>
+std::size_t buffered_write_stream<Stream>::write_some(
+    const ConstBufferSequence& buffers)
+{
+  using asio::buffer_size;
+  if (buffer_size(buffers) == 0)
+    return 0;
+
+  if (storage_.size() == storage_.capacity())
+    this->flush();
+
+  return this->copy(buffers);
+}
+
+template <typename Stream>
+template <typename ConstBufferSequence>
+std::size_t buffered_write_stream<Stream>::write_some(
+    const ConstBufferSequence& buffers, asio::error_code& ec)
+{
+  ec = asio::error_code();
+
+  using asio::buffer_size;
+  if (buffer_size(buffers) == 0)
+    return 0;
+
+  if (storage_.size() == storage_.capacity() && !flush(ec))
+    return 0;
+
+  return this->copy(buffers);
+}
+
+namespace detail
+{
+  template <typename ConstBufferSequence, typename WriteHandler>
+  class buffered_write_some_handler
+  {
+  public:
+    buffered_write_some_handler(detail::buffered_stream_storage& storage,
+        const ConstBufferSequence& buffers, WriteHandler& handler)
+      : storage_(storage),
+        buffers_(buffers),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+      buffered_write_some_handler(const buffered_write_some_handler& other)
+        : storage_(other.storage_),
+          buffers_(other.buffers_),
+          handler_(other.handler_)
+      {
+      }
+
+      buffered_write_some_handler(buffered_write_some_handler&& other)
+        : storage_(other.storage_),
+          buffers_(other.buffers_),
+          handler_(ASIO_MOVE_CAST(WriteHandler)(other.handler_))
+      {
+      }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec, std::size_t)
+    {
+      if (ec)
+      {
+        const std::size_t length = 0;
+        handler_(ec, length);
+      }
+      else
+      {
+        using asio::buffer_size;
+        std::size_t orig_size = storage_.size();
+        std::size_t space_avail = storage_.capacity() - orig_size;
+        std::size_t bytes_avail = buffer_size(buffers_);
+        std::size_t length = bytes_avail < space_avail
+          ? bytes_avail : space_avail;
+        storage_.resize(orig_size + length);
+        const std::size_t bytes_copied = asio::buffer_copy(
+            storage_.data() + orig_size, buffers_, length);
+        handler_(ec, bytes_copied);
+      }
+    }
+
+  //private:
+    detail::buffered_stream_storage& storage_;
+    ConstBufferSequence buffers_;
+    WriteHandler handler_;
+  };
+
+  template <typename ConstBufferSequence, typename WriteHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      buffered_write_some_handler<
+        ConstBufferSequence, WriteHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename ConstBufferSequence, typename WriteHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      buffered_write_some_handler<
+        ConstBufferSequence, WriteHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename ConstBufferSequence, typename WriteHandler>
+  inline bool asio_handler_is_continuation(
+      buffered_write_some_handler<
+        ConstBufferSequence, WriteHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename ConstBufferSequence,
+      typename WriteHandler>
+  inline void asio_handler_invoke(Function& function,
+      buffered_write_some_handler<
+        ConstBufferSequence, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename ConstBufferSequence,
+      typename WriteHandler>
+  inline void asio_handler_invoke(const Function& function,
+      buffered_write_some_handler<
+        ConstBufferSequence, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename ConstBufferSequence,
+    typename WriteHandler, typename Allocator>
+struct associated_allocator<
+    detail::buffered_write_some_handler<ConstBufferSequence, WriteHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<WriteHandler, Allocator>::type type;
+
+  static type get(
+      const detail::buffered_write_some_handler<
+        ConstBufferSequence, WriteHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<WriteHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename ConstBufferSequence,
+    typename WriteHandler, typename Executor>
+struct associated_executor<
+    detail::buffered_write_some_handler<ConstBufferSequence, WriteHandler>,
+    Executor>
+{
+  typedef typename associated_executor<WriteHandler, Executor>::type type;
+
+  static type get(
+      const detail::buffered_write_some_handler<
+        ConstBufferSequence, WriteHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<WriteHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename Stream>
+template <typename ConstBufferSequence, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+buffered_write_stream<Stream>::async_write_some(
+    const ConstBufferSequence& buffers,
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  using asio::buffer_size;
+  if (buffer_size(buffers) == 0
+      || storage_.size() < storage_.capacity())
+  {
+    next_layer_.async_write_some(ASIO_CONST_BUFFER(0, 0),
+        detail::buffered_write_some_handler<
+          ConstBufferSequence, ASIO_HANDLER_TYPE(
+            WriteHandler, void (asio::error_code, std::size_t))>(
+            storage_, buffers, init.completion_handler));
+  }
+  else
+  {
+    this->async_flush(detail::buffered_write_some_handler<
+          ConstBufferSequence, ASIO_HANDLER_TYPE(
+            WriteHandler, void (asio::error_code, std::size_t))>(
+            storage_, buffers, init.completion_handler));
+  }
+
+  return init.result.get();
+}
+
+template <typename Stream>
+template <typename ConstBufferSequence>
+std::size_t buffered_write_stream<Stream>::copy(
+    const ConstBufferSequence& buffers)
+{
+  using asio::buffer_size;
+  std::size_t orig_size = storage_.size();
+  std::size_t space_avail = storage_.capacity() - orig_size;
+  std::size_t bytes_avail = buffer_size(buffers);
+  std::size_t length = bytes_avail < space_avail ? bytes_avail : space_avail;
+  storage_.resize(orig_size + length);
+  return asio::buffer_copy(
+      storage_.data() + orig_size, buffers, length);
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_BUFFERED_WRITE_STREAM_HPP
diff --git a/subprojects/asio/include/asio/impl/connect.hpp b/subprojects/asio/include/asio/impl/connect.hpp
new file mode 100644
index 000000000..bff1913b1
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/connect.hpp
@@ -0,0 +1,860 @@
+//
+// impl/connect.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_CONNECT_HPP
+#define ASIO_IMPL_CONNECT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <algorithm>
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/post.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  struct default_connect_condition
+  {
+    template <typename Endpoint>
+    bool operator()(const asio::error_code&, const Endpoint&)
+    {
+      return true;
+    }
+  };
+
+  template <typename Protocol, typename Iterator>
+  inline typename Protocol::endpoint deref_connect_result(
+      Iterator iter, asio::error_code& ec)
+  {
+    return ec ? typename Protocol::endpoint() : *iter;
+  }
+
+  template <typename T, typename Iterator>
+  struct legacy_connect_condition_helper : T
+  {
+    typedef char (*fallback_func_type)(...);
+    operator fallback_func_type() const;
+  };
+
+  template <typename R, typename Arg1, typename Arg2, typename Iterator>
+  struct legacy_connect_condition_helper<R (*)(Arg1, Arg2), Iterator>
+  {
+    R operator()(Arg1, Arg2) const;
+    char operator()(...) const;
+  };
+
+  template <typename T, typename Iterator>
+  struct is_legacy_connect_condition
+  {
+    static char asio_connect_condition_check(char);
+    static char (&asio_connect_condition_check(Iterator))[2];
+
+    static const bool value =
+      sizeof(asio_connect_condition_check(
+        (*static_cast<legacy_connect_condition_helper<T, Iterator>*>(0))(
+          *static_cast<const asio::error_code*>(0),
+          *static_cast<const Iterator*>(0)))) != 1;
+  };
+
+  template <typename ConnectCondition, typename Iterator>
+  inline Iterator call_connect_condition(ConnectCondition& connect_condition,
+      const asio::error_code& ec, Iterator next, Iterator end,
+      typename enable_if<is_legacy_connect_condition<
+        ConnectCondition, Iterator>::value>::type* = 0)
+  {
+    if (next != end)
+      return connect_condition(ec, next);
+    return end;
+  }
+
+  template <typename ConnectCondition, typename Iterator>
+  inline Iterator call_connect_condition(ConnectCondition& connect_condition,
+      const asio::error_code& ec, Iterator next, Iterator end,
+      typename enable_if<!is_legacy_connect_condition<
+        ConnectCondition, Iterator>::value>::type* = 0)
+  {
+    for (;next != end; ++next)
+      if (connect_condition(ec, *next))
+        return next;
+    return end;
+  }
+}
+
+template <typename Protocol ASIO_SVC_TPARAM, typename EndpointSequence>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type*)
+{
+  asio::error_code ec;
+  typename Protocol::endpoint result = connect(s, endpoints, ec);
+  asio::detail::throw_error(ec, "connect");
+  return result;
+}
+
+template <typename Protocol ASIO_SVC_TPARAM, typename EndpointSequence>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, asio::error_code& ec,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type*)
+{
+  return detail::deref_connect_result<Protocol>(
+      connect(s, endpoints.begin(), endpoints.end(),
+        detail::default_connect_condition(), ec), ec);
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s, Iterator begin,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type*)
+{
+  asio::error_code ec;
+  Iterator result = connect(s, begin, ec);
+  asio::detail::throw_error(ec, "connect");
+  return result;
+}
+
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+inline Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, asio::error_code& ec,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type*)
+{
+  return connect(s, begin, Iterator(), detail::default_connect_condition(), ec);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end)
+{
+  asio::error_code ec;
+  Iterator result = connect(s, begin, end, ec);
+  asio::detail::throw_error(ec, "connect");
+  return result;
+}
+
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator>
+inline Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end, asio::error_code& ec)
+{
+  return connect(s, begin, end, detail::default_connect_condition(), ec);
+}
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename ConnectCondition>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, ConnectCondition connect_condition,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type*)
+{
+  asio::error_code ec;
+  typename Protocol::endpoint result = connect(
+      s, endpoints, connect_condition, ec);
+  asio::detail::throw_error(ec, "connect");
+  return result;
+}
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename ConnectCondition>
+typename Protocol::endpoint connect(
+    basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, ConnectCondition connect_condition,
+    asio::error_code& ec,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type*)
+{
+  return detail::deref_connect_result<Protocol>(
+      connect(s, endpoints.begin(), endpoints.end(),
+        connect_condition, ec), ec);
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, ConnectCondition connect_condition,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type*)
+{
+  asio::error_code ec;
+  Iterator result = connect(s, begin, connect_condition, ec);
+  asio::detail::throw_error(ec, "connect");
+  return result;
+}
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+inline Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, ConnectCondition connect_condition,
+    asio::error_code& ec,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type*)
+{
+  return connect(s, begin, Iterator(), connect_condition, ec);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end, ConnectCondition connect_condition)
+{
+  asio::error_code ec;
+  Iterator result = connect(s, begin, end, connect_condition, ec);
+  asio::detail::throw_error(ec, "connect");
+  return result;
+}
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition>
+Iterator connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end, ConnectCondition connect_condition,
+    asio::error_code& ec)
+{
+  ec = asio::error_code();
+
+  for (Iterator iter = begin; iter != end; ++iter)
+  {
+    iter = (detail::call_connect_condition(connect_condition, ec, iter, end));
+    if (iter != end)
+    {
+      s.close(ec);
+      s.connect(*iter, ec);
+      if (!ec)
+        return iter;
+    }
+    else
+      break;
+  }
+
+  if (!ec)
+    ec = asio::error::not_found;
+
+  return end;
+}
+
+namespace detail
+{
+  // Enable the empty base class optimisation for the connect condition.
+  template <typename ConnectCondition>
+  class base_from_connect_condition
+  {
+  protected:
+    explicit base_from_connect_condition(
+        const ConnectCondition& connect_condition)
+      : connect_condition_(connect_condition)
+    {
+    }
+
+    template <typename Iterator>
+    void check_condition(const asio::error_code& ec,
+        Iterator& iter, Iterator& end)
+    {
+      iter = detail::call_connect_condition(connect_condition_, ec, iter, end);
+    }
+
+  private:
+    ConnectCondition connect_condition_;
+  };
+
+  // The default_connect_condition implementation is essentially a no-op. This
+  // template specialisation lets us eliminate all costs associated with it.
+  template <>
+  class base_from_connect_condition<default_connect_condition>
+  {
+  protected:
+    explicit base_from_connect_condition(const default_connect_condition&)
+    {
+    }
+
+    template <typename Iterator>
+    void check_condition(const asio::error_code&, Iterator&, Iterator&)
+    {
+    }
+  };
+
+  template <typename Protocol ASIO_SVC_TPARAM,
+      typename EndpointSequence, typename ConnectCondition,
+      typename RangeConnectHandler>
+  class range_connect_op : base_from_connect_condition<ConnectCondition>
+  {
+  public:
+    range_connect_op(basic_socket<Protocol ASIO_SVC_TARG>& sock,
+        const EndpointSequence& endpoints,
+        const ConnectCondition& connect_condition,
+        RangeConnectHandler& handler)
+      : base_from_connect_condition<ConnectCondition>(connect_condition),
+        socket_(sock),
+        endpoints_(endpoints),
+        index_(0),
+        start_(0),
+        handler_(ASIO_MOVE_CAST(RangeConnectHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    range_connect_op(const range_connect_op& other)
+      : base_from_connect_condition<ConnectCondition>(other),
+        socket_(other.socket_),
+        endpoints_(other.endpoints_),
+        index_(other.index_),
+        start_(other.start_),
+        handler_(other.handler_)
+    {
+    }
+
+    range_connect_op(range_connect_op&& other)
+      : base_from_connect_condition<ConnectCondition>(other),
+        socket_(other.socket_),
+        endpoints_(other.endpoints_),
+        index_(other.index_),
+        start_(other.start_),
+        handler_(ASIO_MOVE_CAST(RangeConnectHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(asio::error_code ec, int start = 0)
+    {
+      typename EndpointSequence::const_iterator begin = endpoints_.begin();
+      typename EndpointSequence::const_iterator iter = begin;
+      std::advance(iter, index_);
+      typename EndpointSequence::const_iterator end = endpoints_.end();
+
+      switch (start_ = start)
+      {
+        case 1:
+        for (;;)
+        {
+          this->check_condition(ec, iter, end);
+          index_ = std::distance(begin, iter);
+
+          if (iter != end)
+          {
+            socket_.close(ec);
+            socket_.async_connect(*iter,
+                ASIO_MOVE_CAST(range_connect_op)(*this));
+            return;
+          }
+
+          if (start)
+          {
+            ec = asio::error::not_found;
+            asio::post(socket_.get_executor(),
+                detail::bind_handler(
+                  ASIO_MOVE_CAST(range_connect_op)(*this), ec));
+            return;
+          }
+
+          default:
+
+          if (iter == end)
+            break;
+
+          if (!socket_.is_open())
+          {
+            ec = asio::error::operation_aborted;
+            break;
+          }
+
+          if (!ec)
+            break;
+
+          ++iter;
+          ++index_;
+        }
+
+        handler_(static_cast<const asio::error_code&>(ec),
+            static_cast<const typename Protocol::endpoint&>(
+              ec || iter == end ? typename Protocol::endpoint() : *iter));
+      }
+    }
+
+  //private:
+    basic_socket<Protocol ASIO_SVC_TARG>& socket_;
+    EndpointSequence endpoints_;
+    std::size_t index_;
+    int start_;
+    RangeConnectHandler handler_;
+  };
+
+  template <typename Protocol ASIO_SVC_TPARAM,
+      typename EndpointSequence, typename ConnectCondition,
+      typename RangeConnectHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      range_connect_op<Protocol ASIO_SVC_TARG, EndpointSequence,
+        ConnectCondition, RangeConnectHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename Protocol ASIO_SVC_TPARAM,
+      typename EndpointSequence, typename ConnectCondition,
+      typename RangeConnectHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      range_connect_op<Protocol ASIO_SVC_TARG, EndpointSequence,
+        ConnectCondition, RangeConnectHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename Protocol ASIO_SVC_TPARAM,
+      typename EndpointSequence, typename ConnectCondition,
+      typename RangeConnectHandler>
+  inline bool asio_handler_is_continuation(
+      range_connect_op<Protocol ASIO_SVC_TARG, EndpointSequence,
+        ConnectCondition, RangeConnectHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+        this_handler->handler_);
+  }
+
+  template <typename Function, typename Protocol
+      ASIO_SVC_TPARAM, typename EndpointSequence,
+      typename ConnectCondition, typename RangeConnectHandler>
+  inline void asio_handler_invoke(Function& function,
+      range_connect_op<Protocol ASIO_SVC_TARG, EndpointSequence,
+        ConnectCondition, RangeConnectHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename Protocol
+      ASIO_SVC_TPARAM, typename EndpointSequence,
+      typename ConnectCondition, typename RangeConnectHandler>
+  inline void asio_handler_invoke(const Function& function,
+      range_connect_op<Protocol ASIO_SVC_TARG, EndpointSequence,
+        ConnectCondition, RangeConnectHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+      typename ConnectCondition, typename IteratorConnectHandler>
+  class iterator_connect_op : base_from_connect_condition<ConnectCondition>
+  {
+  public:
+    iterator_connect_op(basic_socket<Protocol ASIO_SVC_TARG>& sock,
+        const Iterator& begin, const Iterator& end,
+        const ConnectCondition& connect_condition,
+        IteratorConnectHandler& handler)
+      : base_from_connect_condition<ConnectCondition>(connect_condition),
+        socket_(sock),
+        iter_(begin),
+        end_(end),
+        start_(0),
+        handler_(ASIO_MOVE_CAST(IteratorConnectHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    iterator_connect_op(const iterator_connect_op& other)
+      : base_from_connect_condition<ConnectCondition>(other),
+        socket_(other.socket_),
+        iter_(other.iter_),
+        end_(other.end_),
+        start_(other.start_),
+        handler_(other.handler_)
+    {
+    }
+
+    iterator_connect_op(iterator_connect_op&& other)
+      : base_from_connect_condition<ConnectCondition>(other),
+        socket_(other.socket_),
+        iter_(other.iter_),
+        end_(other.end_),
+        start_(other.start_),
+        handler_(ASIO_MOVE_CAST(IteratorConnectHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(asio::error_code ec, int start = 0)
+    {
+      switch (start_ = start)
+      {
+        case 1:
+        for (;;)
+        {
+          this->check_condition(ec, iter_, end_);
+
+          if (iter_ != end_)
+          {
+            socket_.close(ec);
+            socket_.async_connect(*iter_,
+                ASIO_MOVE_CAST(iterator_connect_op)(*this));
+            return;
+          }
+
+          if (start)
+          {
+            ec = asio::error::not_found;
+            asio::post(socket_.get_executor(),
+                detail::bind_handler(
+                  ASIO_MOVE_CAST(iterator_connect_op)(*this), ec));
+            return;
+          }
+
+          default:
+
+          if (iter_ == end_)
+            break;
+
+          if (!socket_.is_open())
+          {
+            ec = asio::error::operation_aborted;
+            break;
+          }
+
+          if (!ec)
+            break;
+
+          ++iter_;
+        }
+
+        handler_(static_cast<const asio::error_code&>(ec),
+            static_cast<const Iterator&>(iter_));
+      }
+    }
+
+  //private:
+    basic_socket<Protocol ASIO_SVC_TARG>& socket_;
+    Iterator iter_;
+    Iterator end_;
+    int start_;
+    IteratorConnectHandler handler_;
+  };
+
+  template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+      typename ConnectCondition, typename IteratorConnectHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+        ConnectCondition, IteratorConnectHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+      typename ConnectCondition, typename IteratorConnectHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+        ConnectCondition, IteratorConnectHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+      typename ConnectCondition, typename IteratorConnectHandler>
+  inline bool asio_handler_is_continuation(
+      iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+        ConnectCondition, IteratorConnectHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+        this_handler->handler_);
+  }
+
+  template <typename Function, typename Protocol
+      ASIO_SVC_TPARAM, typename Iterator,
+      typename ConnectCondition, typename IteratorConnectHandler>
+  inline void asio_handler_invoke(Function& function,
+      iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+        ConnectCondition, IteratorConnectHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename Protocol
+      ASIO_SVC_TPARAM, typename Iterator,
+      typename ConnectCondition, typename IteratorConnectHandler>
+  inline void asio_handler_invoke(const Function& function,
+      iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+        ConnectCondition, IteratorConnectHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename ConnectCondition,
+    typename RangeConnectHandler, typename Allocator>
+struct associated_allocator<
+    detail::range_connect_op<Protocol ASIO_SVC_TARG,
+      EndpointSequence, ConnectCondition, RangeConnectHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<
+      RangeConnectHandler, Allocator>::type type;
+
+  static type get(
+      const detail::range_connect_op<Protocol ASIO_SVC_TARG,
+        EndpointSequence, ConnectCondition, RangeConnectHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<RangeConnectHandler,
+        Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename ConnectCondition,
+    typename RangeConnectHandler, typename Executor>
+struct associated_executor<
+    detail::range_connect_op<Protocol ASIO_SVC_TARG,
+      EndpointSequence, ConnectCondition, RangeConnectHandler>,
+    Executor>
+{
+  typedef typename associated_executor<
+      RangeConnectHandler, Executor>::type type;
+
+  static type get(
+      const detail::range_connect_op<Protocol ASIO_SVC_TARG,
+        EndpointSequence, ConnectCondition, RangeConnectHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<RangeConnectHandler,
+        Executor>::get(h.handler_, ex);
+  }
+};
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition,
+    typename IteratorConnectHandler, typename Allocator>
+struct associated_allocator<
+    detail::iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+      ConnectCondition, IteratorConnectHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<
+      IteratorConnectHandler, Allocator>::type type;
+
+  static type get(
+      const detail::iterator_connect_op<Protocol ASIO_SVC_TARG,
+        Iterator, ConnectCondition, IteratorConnectHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<IteratorConnectHandler,
+        Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename ConnectCondition,
+    typename IteratorConnectHandler, typename Executor>
+struct associated_executor<
+    detail::iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+      ConnectCondition, IteratorConnectHandler>,
+    Executor>
+{
+  typedef typename associated_executor<
+      IteratorConnectHandler, Executor>::type type;
+
+  static type get(
+      const detail::iterator_connect_op<Protocol ASIO_SVC_TARG,
+        Iterator, ConnectCondition, IteratorConnectHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<IteratorConnectHandler,
+        Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename EndpointSequence, typename RangeConnectHandler>
+inline ASIO_INITFN_RESULT_TYPE(RangeConnectHandler,
+    void (asio::error_code, typename Protocol::endpoint))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints,
+    ASIO_MOVE_ARG(RangeConnectHandler) handler,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a RangeConnectHandler.
+  ASIO_RANGE_CONNECT_HANDLER_CHECK(
+      RangeConnectHandler, handler, typename Protocol::endpoint) type_check;
+
+  async_completion<RangeConnectHandler,
+    void (asio::error_code, typename Protocol::endpoint)>
+      init(handler);
+
+  detail::range_connect_op<Protocol ASIO_SVC_TARG, EndpointSequence,
+    detail::default_connect_condition,
+      ASIO_HANDLER_TYPE(RangeConnectHandler,
+        void (asio::error_code, typename Protocol::endpoint))>(s,
+          endpoints, detail::default_connect_condition(),
+            init.completion_handler)(asio::error_code(), 1);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename IteratorConnectHandler>
+inline ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, ASIO_MOVE_ARG(IteratorConnectHandler) handler,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a IteratorConnectHandler.
+  ASIO_ITERATOR_CONNECT_HANDLER_CHECK(
+      IteratorConnectHandler, handler, Iterator) type_check;
+
+  async_completion<IteratorConnectHandler,
+    void (asio::error_code, Iterator)> init(handler);
+
+  detail::iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+    detail::default_connect_condition, ASIO_HANDLER_TYPE(
+      IteratorConnectHandler, void (asio::error_code, Iterator))>(s,
+        begin, Iterator(), detail::default_connect_condition(),
+          init.completion_handler)(asio::error_code(), 1);
+
+  return init.result.get();
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Protocol ASIO_SVC_TPARAM,
+    typename Iterator, typename IteratorConnectHandler>
+inline ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end,
+    ASIO_MOVE_ARG(IteratorConnectHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a IteratorConnectHandler.
+  ASIO_ITERATOR_CONNECT_HANDLER_CHECK(
+      IteratorConnectHandler, handler, Iterator) type_check;
+
+  async_completion<IteratorConnectHandler,
+    void (asio::error_code, Iterator)> init(handler);
+
+  detail::iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+    detail::default_connect_condition, ASIO_HANDLER_TYPE(
+      IteratorConnectHandler, void (asio::error_code, Iterator))>(s,
+        begin, end, detail::default_connect_condition(),
+          init.completion_handler)(asio::error_code(), 1);
+
+  return init.result.get();
+}
+
+template <typename Protocol ASIO_SVC_TPARAM, typename EndpointSequence,
+    typename ConnectCondition, typename RangeConnectHandler>
+inline ASIO_INITFN_RESULT_TYPE(RangeConnectHandler,
+    void (asio::error_code, typename Protocol::endpoint))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    const EndpointSequence& endpoints, ConnectCondition connect_condition,
+    ASIO_MOVE_ARG(RangeConnectHandler) handler,
+    typename enable_if<is_endpoint_sequence<
+        EndpointSequence>::value>::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a RangeConnectHandler.
+  ASIO_RANGE_CONNECT_HANDLER_CHECK(
+      RangeConnectHandler, handler, typename Protocol::endpoint) type_check;
+
+  async_completion<RangeConnectHandler,
+    void (asio::error_code, typename Protocol::endpoint)>
+      init(handler);
+
+  detail::range_connect_op<Protocol ASIO_SVC_TARG, EndpointSequence,
+    ConnectCondition, ASIO_HANDLER_TYPE(RangeConnectHandler,
+      void (asio::error_code, typename Protocol::endpoint))>(s,
+        endpoints, connect_condition, init.completion_handler)(
+          asio::error_code(), 1);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+    typename ConnectCondition, typename IteratorConnectHandler>
+inline ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, ConnectCondition connect_condition,
+    ASIO_MOVE_ARG(IteratorConnectHandler) handler,
+    typename enable_if<!is_endpoint_sequence<Iterator>::value>::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a IteratorConnectHandler.
+  ASIO_ITERATOR_CONNECT_HANDLER_CHECK(
+      IteratorConnectHandler, handler, Iterator) type_check;
+
+  async_completion<IteratorConnectHandler,
+    void (asio::error_code, Iterator)> init(handler);
+
+  detail::iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+    ConnectCondition, ASIO_HANDLER_TYPE(
+      IteratorConnectHandler, void (asio::error_code, Iterator))>(s,
+        begin, Iterator(), connect_condition, init.completion_handler)(
+          asio::error_code(), 1);
+
+  return init.result.get();
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Protocol ASIO_SVC_TPARAM, typename Iterator,
+    typename ConnectCondition, typename IteratorConnectHandler>
+inline ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,
+    void (asio::error_code, Iterator))
+async_connect(basic_socket<Protocol ASIO_SVC_TARG>& s,
+    Iterator begin, Iterator end, ConnectCondition connect_condition,
+    ASIO_MOVE_ARG(IteratorConnectHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a IteratorConnectHandler.
+  ASIO_ITERATOR_CONNECT_HANDLER_CHECK(
+      IteratorConnectHandler, handler, Iterator) type_check;
+
+  async_completion<IteratorConnectHandler,
+    void (asio::error_code, Iterator)> init(handler);
+
+  detail::iterator_connect_op<Protocol ASIO_SVC_TARG, Iterator,
+    ConnectCondition, ASIO_HANDLER_TYPE(
+      IteratorConnectHandler, void (asio::error_code, Iterator))>(s,
+        begin, end, connect_condition, init.completion_handler)(
+          asio::error_code(), 1);
+
+  return init.result.get();
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_CONNECT_HPP
diff --git a/subprojects/asio/include/asio/impl/defer.hpp b/subprojects/asio/include/asio/impl/defer.hpp
new file mode 100644
index 000000000..a27df0f13
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/defer.hpp
@@ -0,0 +1,77 @@
+//
+// impl/defer.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_DEFER_HPP
+#define ASIO_IMPL_DEFER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/work_dispatcher.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) defer(
+    ASIO_MOVE_ARG(CompletionToken) token)
+{
+  typedef ASIO_HANDLER_TYPE(CompletionToken, void()) handler;
+
+  async_completion<CompletionToken, void()> init(token);
+
+  typename associated_executor<handler>::type ex(
+      (get_associated_executor)(init.completion_handler));
+
+  typename associated_allocator<handler>::type alloc(
+      (get_associated_allocator)(init.completion_handler));
+
+  ex.defer(ASIO_MOVE_CAST(handler)(init.completion_handler), alloc);
+
+  return init.result.get();
+}
+
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) defer(
+    const Executor& ex, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_executor<Executor>::value>::type*)
+{
+  typedef ASIO_HANDLER_TYPE(CompletionToken, void()) handler;
+
+  async_completion<CompletionToken, void()> init(token);
+
+  typename associated_allocator<handler>::type alloc(
+      (get_associated_allocator)(init.completion_handler));
+
+  ex.defer(detail::work_dispatcher<handler>(init.completion_handler), alloc);
+
+  return init.result.get();
+}
+
+template <typename ExecutionContext, typename CompletionToken>
+inline ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) defer(
+    ExecutionContext& ctx, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type*)
+{
+  return (defer)(ctx.get_executor(),
+      ASIO_MOVE_CAST(CompletionToken)(token));
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_DEFER_HPP
diff --git a/subprojects/asio/include/asio/impl/dispatch.hpp b/subprojects/asio/include/asio/impl/dispatch.hpp
new file mode 100644
index 000000000..4e11c6b2e
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/dispatch.hpp
@@ -0,0 +1,78 @@
+//
+// impl/dispatch.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_DISPATCH_HPP
+#define ASIO_IMPL_DISPATCH_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/work_dispatcher.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) dispatch(
+    ASIO_MOVE_ARG(CompletionToken) token)
+{
+  typedef ASIO_HANDLER_TYPE(CompletionToken, void()) handler;
+
+  async_completion<CompletionToken, void()> init(token);
+
+  typename associated_executor<handler>::type ex(
+      (get_associated_executor)(init.completion_handler));
+
+  typename associated_allocator<handler>::type alloc(
+      (get_associated_allocator)(init.completion_handler));
+
+  ex.dispatch(ASIO_MOVE_CAST(handler)(init.completion_handler), alloc);
+
+  return init.result.get();
+}
+
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) dispatch(
+    const Executor& ex, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_executor<Executor>::value>::type*)
+{
+  typedef ASIO_HANDLER_TYPE(CompletionToken, void()) handler;
+
+  async_completion<CompletionToken, void()> init(token);
+
+  typename associated_allocator<handler>::type alloc(
+      (get_associated_allocator)(init.completion_handler));
+
+  ex.dispatch(detail::work_dispatcher<handler>(
+        init.completion_handler), alloc);
+
+  return init.result.get();
+}
+
+template <typename ExecutionContext, typename CompletionToken>
+inline ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) dispatch(
+    ExecutionContext& ctx, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type*)
+{
+  return (dispatch)(ctx.get_executor(),
+      ASIO_MOVE_CAST(CompletionToken)(token));
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_DISPATCH_HPP
diff --git a/subprojects/asio/include/asio/impl/error.ipp b/subprojects/asio/include/asio/impl/error.ipp
new file mode 100644
index 000000000..6b1f33a4c
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/error.ipp
@@ -0,0 +1,128 @@
+//
+// impl/error.ipp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_ERROR_IPP
+#define ASIO_IMPL_ERROR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace error {
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+namespace detail {
+
+class netdb_category : public asio::error_category
+{
+public:
+  const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT
+  {
+    return "asio.netdb";
+  }
+
+  std::string message(int value) const
+  {
+    if (value == error::host_not_found)
+      return "Host not found (authoritative)";
+    if (value == error::host_not_found_try_again)
+      return "Host not found (non-authoritative), try again later";
+    if (value == error::no_data)
+      return "The query is valid, but it does not have associated data";
+    if (value == error::no_recovery)
+      return "A non-recoverable error occurred during database lookup";
+    return "asio.netdb error";
+  }
+};
+
+} // namespace detail
+
+const asio::error_category& get_netdb_category()
+{
+  static detail::netdb_category instance;
+  return instance;
+}
+
+namespace detail {
+
+class addrinfo_category : public asio::error_category
+{
+public:
+  const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT
+  {
+    return "asio.addrinfo";
+  }
+
+  std::string message(int value) const
+  {
+    if (value == error::service_not_found)
+      return "Service not found";
+    if (value == error::socket_type_not_supported)
+      return "Socket type not supported";
+    return "asio.addrinfo error";
+  }
+};
+
+} // namespace detail
+
+const asio::error_category& get_addrinfo_category()
+{
+  static detail::addrinfo_category instance;
+  return instance;
+}
+
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+namespace detail {
+
+class misc_category : public asio::error_category
+{
+public:
+  const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT
+  {
+    return "asio.misc";
+  }
+
+  std::string message(int value) const
+  {
+    if (value == error::already_open)
+      return "Already open";
+    if (value == error::eof)
+      return "End of file";
+    if (value == error::not_found)
+      return "Element not found";
+    if (value == error::fd_set_failure)
+      return "The descriptor does not fit into the select call's fd_set";
+    return "asio.misc error";
+  }
+};
+
+} // namespace detail
+
+const asio::error_category& get_misc_category()
+{
+  static detail::misc_category instance;
+  return instance;
+}
+
+} // namespace error
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_ERROR_IPP
diff --git a/subprojects/asio/include/asio/impl/error_code.ipp b/subprojects/asio/include/asio/impl/error_code.ipp
new file mode 100644
index 000000000..0c8a82782
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/error_code.ipp
@@ -0,0 +1,206 @@
+//
+// impl/error_code.ipp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_ERROR_CODE_IPP
+#define ASIO_IMPL_ERROR_CODE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# include <winerror.h>
+#elif defined(ASIO_WINDOWS_RUNTIME)
+# include <windows.h>
+#else
+# include <cerrno>
+# include <cstring>
+# include <string>
+#endif
+#include "asio/detail/local_free_on_block_exit.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/error_code.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+class system_category : public error_category
+{
+public:
+  const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT
+  {
+    return "asio.system";
+  }
+
+  std::string message(int value) const
+  {
+#if defined(ASIO_WINDOWS_RUNTIME) || defined(ASIO_WINDOWS_APP)
+    std::wstring wmsg(128, wchar_t());
+    for (;;)
+    {
+      DWORD wlength = ::FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM
+          | FORMAT_MESSAGE_IGNORE_INSERTS, 0, value,
+          MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+          &wmsg[0], static_cast<DWORD>(wmsg.size()), 0);
+      if (wlength == 0 && ::GetLastError() == ERROR_INSUFFICIENT_BUFFER)
+      {
+        wmsg.resize(wmsg.size() + wmsg.size() / 2);
+        continue;
+      }
+      if (wlength && wmsg[wlength - 1] == '\n')
+        --wlength;
+      if (wlength && wmsg[wlength - 1] == '\r')
+        --wlength;
+      if (wlength)
+      {
+        std::string msg(wlength * 2, char());
+        int length = ::WideCharToMultiByte(CP_ACP, 0,
+            wmsg.c_str(), static_cast<int>(wlength),
+            &msg[0], static_cast<int>(wlength * 2), 0, 0);
+        if (length <= 0)
+          return "asio.system error";
+        msg.resize(static_cast<std::size_t>(length));
+        return msg;
+      }
+      else
+        return "asio.system error";
+    }
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    char* msg = 0;
+    DWORD length = ::FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER
+        | FORMAT_MESSAGE_FROM_SYSTEM
+        | FORMAT_MESSAGE_IGNORE_INSERTS, 0, value,
+        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (char*)&msg, 0, 0);
+    detail::local_free_on_block_exit local_free_obj(msg);
+    if (length && msg[length - 1] == '\n')
+      msg[--length] = '\0';
+    if (length && msg[length - 1] == '\r')
+      msg[--length] = '\0';
+    if (length)
+      return msg;
+    else
+      return "asio.system error";
+#else // defined(ASIO_WINDOWS_DESKTOP) || defined(__CYGWIN__)
+#if !defined(__sun)
+    if (value == ECANCELED)
+      return "Operation aborted.";
+#endif // !defined(__sun)
+#if defined(__sun) || defined(__QNX__) || defined(__SYMBIAN32__)
+    using namespace std;
+    return strerror(value);
+#else
+    char buf[256] = "";
+    using namespace std;
+    return strerror_result(strerror_r(value, buf, sizeof(buf)), buf);
+#endif
+#endif // defined(ASIO_WINDOWS_DESKTOP) || defined(__CYGWIN__)
+  }
+
+#if defined(ASIO_HAS_STD_ERROR_CODE)
+  std::error_condition default_error_condition(
+      int ev) const ASIO_ERROR_CATEGORY_NOEXCEPT
+  {
+    switch (ev)
+    {
+    case access_denied:
+      return std::errc::permission_denied;
+    case address_family_not_supported:
+      return std::errc::address_family_not_supported;
+    case address_in_use:
+      return std::errc::address_in_use;
+    case already_connected:
+      return std::errc::already_connected;
+    case already_started:
+      return std::errc::connection_already_in_progress;
+    case broken_pipe:
+      return std::errc::broken_pipe;
+    case connection_aborted:
+      return std::errc::connection_aborted;
+    case connection_refused:
+      return std::errc::connection_refused;
+    case connection_reset:
+      return std::errc::connection_reset;
+    case bad_descriptor:
+      return std::errc::bad_file_descriptor;
+    case fault:
+      return std::errc::bad_address;
+    case host_unreachable:
+      return std::errc::host_unreachable;
+    case in_progress:
+      return std::errc::operation_in_progress;
+    case interrupted:
+      return std::errc::interrupted;
+    case invalid_argument:
+      return std::errc::invalid_argument;
+    case message_size:
+      return std::errc::message_size;
+    case name_too_long:
+      return std::errc::filename_too_long;
+    case network_down:
+      return std::errc::network_down;
+    case network_reset:
+      return std::errc::network_reset;
+    case network_unreachable:
+      return std::errc::network_unreachable;
+    case no_descriptors:
+      return std::errc::too_many_files_open;
+    case no_buffer_space:
+      return std::errc::no_buffer_space;
+    case no_memory:
+      return std::errc::not_enough_memory;
+    case no_permission:
+      return std::errc::operation_not_permitted;
+    case no_protocol_option:
+      return std::errc::no_protocol_option;
+    case no_such_device:
+      return std::errc::no_such_device;
+    case not_connected:
+      return std::errc::not_connected;
+    case not_socket:
+      return std::errc::not_a_socket;
+    case operation_aborted:
+      return std::errc::operation_canceled;
+    case operation_not_supported:
+      return std::errc::operation_not_supported;
+    case shut_down:
+      return std::make_error_condition(ev, *this);
+    case timed_out:
+      return std::errc::timed_out;
+    case try_again:
+      return std::errc::resource_unavailable_try_again;
+    case would_block:
+      return std::errc::operation_would_block;
+    default:
+      return std::make_error_condition(ev, *this);
+  }
+#endif // defined(ASIO_HAS_STD_ERROR_CODE)
+
+private:
+  // Helper function to adapt the result from glibc's variant of strerror_r.
+  static const char* strerror_result(int, const char* s) { return s; }
+  static const char* strerror_result(const char* s, const char*) { return s; }
+};
+
+} // namespace detail
+
+const error_category& system_category()
+{
+  static detail::system_category instance;
+  return instance;
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_ERROR_CODE_IPP
diff --git a/subprojects/asio/include/asio/impl/execution_context.hpp b/subprojects/asio/include/asio/impl/execution_context.hpp
new file mode 100644
index 000000000..3d1e457e7
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/execution_context.hpp
@@ -0,0 +1,107 @@
+//
+// impl/execution_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_EXECUTION_CONTEXT_HPP
+#define ASIO_IMPL_EXECUTION_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/detail/service_registry.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename Service>
+inline Service& use_service(execution_context& e)
+{
+  // Check that Service meets the necessary type requirements.
+  (void)static_cast<execution_context::service*>(static_cast<Service*>(0));
+
+  return e.service_registry_->template use_service<Service>();
+}
+
+#if !defined(GENERATING_DOCUMENTATION)
+# if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename Service, typename... Args>
+Service& make_service(execution_context& e, ASIO_MOVE_ARG(Args)... args)
+{
+  detail::scoped_ptr<Service> svc(
+      new Service(e, ASIO_MOVE_CAST(Args)(args)...));
+  e.service_registry_->template add_service<Service>(svc.get());
+  Service& result = *svc;
+  svc.release();
+  return result;
+}
+
+# else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename Service>
+Service& make_service(execution_context& e)
+{
+  detail::scoped_ptr<Service> svc(new Service(e));
+  e.service_registry_->template add_service<Service>(svc.get());
+  Service& result = *svc;
+  svc.release();
+  return result;
+}
+
+#define ASIO_PRIVATE_MAKE_SERVICE_DEF(n) \
+  template <typename Service, ASIO_VARIADIC_TPARAMS(n)> \
+  Service& make_service(execution_context& e, \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    detail::scoped_ptr<Service> svc( \
+        new Service(e, ASIO_VARIADIC_MOVE_ARGS(n))); \
+    e.service_registry_->template add_service<Service>(svc.get()); \
+    Service& result = *svc; \
+    svc.release(); \
+    return result; \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_MAKE_SERVICE_DEF)
+#undef ASIO_PRIVATE_MAKE_SERVICE_DEF
+
+# endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename Service>
+inline void add_service(execution_context& e, Service* svc)
+{
+  // Check that Service meets the necessary type requirements.
+  (void)static_cast<execution_context::service*>(static_cast<Service*>(0));
+
+  e.service_registry_->template add_service<Service>(svc);
+}
+
+template <typename Service>
+inline bool has_service(execution_context& e)
+{
+  // Check that Service meets the necessary type requirements.
+  (void)static_cast<execution_context::service*>(static_cast<Service*>(0));
+
+  return e.service_registry_->template has_service<Service>();
+}
+
+inline execution_context& execution_context::service::context()
+{
+  return owner_;
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_EXECUTION_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/impl/execution_context.ipp b/subprojects/asio/include/asio/impl/execution_context.ipp
new file mode 100644
index 000000000..c2b3b21a3
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/execution_context.ipp
@@ -0,0 +1,82 @@
+//
+// impl/execution_context.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_EXECUTION_CONTEXT_IPP
+#define ASIO_IMPL_EXECUTION_CONTEXT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/detail/service_registry.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+execution_context::execution_context()
+  : service_registry_(new asio::detail::service_registry(*this))
+{
+}
+
+execution_context::~execution_context()
+{
+  shutdown();
+  destroy();
+  delete service_registry_;
+}
+
+void execution_context::shutdown()
+{
+  service_registry_->shutdown_services();
+}
+
+void execution_context::destroy()
+{
+  service_registry_->destroy_services();
+}
+
+void execution_context::notify_fork(
+    asio::execution_context::fork_event event)
+{
+  service_registry_->notify_fork(event);
+}
+
+execution_context::service::service(execution_context& owner)
+  : owner_(owner),
+    next_(0)
+{
+}
+
+execution_context::service::~service()
+{
+}
+
+void execution_context::service::notify_fork(execution_context::fork_event)
+{
+}
+
+service_already_exists::service_already_exists()
+  : std::logic_error("Service already exists.")
+{
+}
+
+invalid_service_owner::invalid_service_owner()
+  : std::logic_error("Invalid service owner.")
+{
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_EXECUTION_CONTEXT_IPP
diff --git a/subprojects/asio/include/asio/impl/executor.hpp b/subprojects/asio/include/asio/impl/executor.hpp
new file mode 100644
index 000000000..0fcf5f54a
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/executor.hpp
@@ -0,0 +1,386 @@
+//
+// impl/executor.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_EXECUTOR_HPP
+#define ASIO_IMPL_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/atomic_count.hpp"
+#include "asio/detail/executor_op.hpp"
+#include "asio/detail/global.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/recycling_allocator.hpp"
+#include "asio/executor.hpp"
+#include "asio/system_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+#if defined(ASIO_HAS_MOVE)
+
+// Lightweight, move-only function object wrapper.
+class executor::function
+{
+public:
+  template <typename F, typename Alloc>
+  explicit function(F f, const Alloc& a)
+  {
+    // Allocate and construct an operation to wrap the function.
+    typedef detail::executor_op<F, Alloc> op;
+    typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+    op_ = new (p.v) op(ASIO_MOVE_CAST(F)(f), a);
+    p.v = 0;
+  }
+
+  function(function&& other)
+    : op_(other.op_)
+  {
+    other.op_ = 0;
+  }
+
+  ~function()
+  {
+    if (op_)
+      op_->destroy();
+  }
+
+  void operator()()
+  {
+    if (op_)
+    {
+      detail::scheduler_operation* op = op_;
+      op_ = 0;
+      op->complete(this, asio::error_code(), 0);
+    }
+  }
+
+private:
+  detail::scheduler_operation* op_;
+};
+
+#else // defined(ASIO_HAS_MOVE)
+
+// Not so lightweight, copyable function object wrapper.
+class executor::function
+{
+public:
+  template <typename F, typename Alloc>
+  explicit function(const F& f, const Alloc&)
+    : impl_(new impl<F>(f))
+  {
+  }
+
+  void operator()()
+  {
+    impl_->invoke_(impl_.get());
+  }
+
+private:
+  // Base class for polymorphic function implementations.
+  struct impl_base
+  {
+    void (*invoke_)(impl_base*);
+  };
+
+  // Polymorphic function implementation.
+  template <typename F>
+  struct impl : impl_base
+  {
+    impl(const F& f)
+      : function_(f)
+    {
+      invoke_ = &function::invoke<F>;
+    }
+
+    F function_;
+  };
+
+  // Helper to invoke a function.
+  template <typename F>
+  static void invoke(impl_base* i)
+  {
+    static_cast<impl<F>*>(i)->function_();
+  }
+
+  detail::shared_ptr<impl_base> impl_;
+};
+
+#endif // defined(ASIO_HAS_MOVE)
+
+// Default polymorphic allocator implementation.
+template <typename Executor, typename Allocator>
+class executor::impl
+  : public executor::impl_base
+{
+public:
+  typedef ASIO_REBIND_ALLOC(Allocator, impl) allocator_type;
+
+  static impl_base* create(const Executor& e, Allocator a = Allocator())
+  {
+    raw_mem mem(a);
+    impl* p = new (mem.ptr_) impl(e, a);
+    mem.ptr_ = 0;
+    return p;
+  }
+
+  impl(const Executor& e, const Allocator& a) ASIO_NOEXCEPT
+    : impl_base(false),
+      ref_count_(1),
+      executor_(e),
+      allocator_(a)
+  {
+  }
+
+  impl_base* clone() const ASIO_NOEXCEPT
+  {
+    ++ref_count_;
+    return const_cast<impl_base*>(static_cast<const impl_base*>(this));
+  }
+
+  void destroy() ASIO_NOEXCEPT
+  {
+    if (--ref_count_ == 0)
+    {
+      allocator_type alloc(allocator_);
+      impl* p = this;
+      p->~impl();
+      alloc.deallocate(p, 1);
+    }
+  }
+
+  void on_work_started() ASIO_NOEXCEPT
+  {
+    executor_.on_work_started();
+  }
+
+  void on_work_finished() ASIO_NOEXCEPT
+  {
+    executor_.on_work_finished();
+  }
+
+  execution_context& context() ASIO_NOEXCEPT
+  {
+    return executor_.context();
+  }
+
+  void dispatch(ASIO_MOVE_ARG(function) f)
+  {
+    executor_.dispatch(ASIO_MOVE_CAST(function)(f), allocator_);
+  }
+
+  void post(ASIO_MOVE_ARG(function) f)
+  {
+    executor_.post(ASIO_MOVE_CAST(function)(f), allocator_);
+  }
+
+  void defer(ASIO_MOVE_ARG(function) f)
+  {
+    executor_.defer(ASIO_MOVE_CAST(function)(f), allocator_);
+  }
+
+  type_id_result_type target_type() const ASIO_NOEXCEPT
+  {
+    return type_id<Executor>();
+  }
+
+  void* target() ASIO_NOEXCEPT
+  {
+    return &executor_;
+  }
+
+  const void* target() const ASIO_NOEXCEPT
+  {
+    return &executor_;
+  }
+
+  bool equals(const impl_base* e) const ASIO_NOEXCEPT
+  {
+    if (this == e)
+      return true;
+    if (target_type() != e->target_type())
+      return false;
+    return executor_ == *static_cast<const Executor*>(e->target());
+  }
+
+private:
+  mutable detail::atomic_count ref_count_;
+  Executor executor_;
+  Allocator allocator_;
+
+  struct raw_mem
+  {
+    allocator_type allocator_;
+    impl* ptr_;
+
+    explicit raw_mem(const Allocator& a)
+      : allocator_(a),
+        ptr_(allocator_.allocate(1))
+    {
+    }
+
+    ~raw_mem()
+    {
+      if (ptr_)
+        allocator_.deallocate(ptr_, 1);
+    }
+
+  private:
+    // Disallow copying and assignment.
+    raw_mem(const raw_mem&);
+    raw_mem operator=(const raw_mem&);
+  };
+};
+
+// Polymorphic allocator specialisation for system_executor.
+template <typename Allocator>
+class executor::impl<system_executor, Allocator>
+  : public executor::impl_base
+{
+public:
+  static impl_base* create(const system_executor&,
+      const Allocator& = Allocator())
+  {
+    return &detail::global<impl<system_executor, std::allocator<void> > >();
+  }
+
+  impl()
+    : impl_base(true)
+  {
+  }
+
+  impl_base* clone() const ASIO_NOEXCEPT
+  {
+    return const_cast<impl_base*>(static_cast<const impl_base*>(this));
+  }
+
+  void destroy() ASIO_NOEXCEPT
+  {
+  }
+
+  void on_work_started() ASIO_NOEXCEPT
+  {
+    executor_.on_work_started();
+  }
+
+  void on_work_finished() ASIO_NOEXCEPT
+  {
+    executor_.on_work_finished();
+  }
+
+  execution_context& context() ASIO_NOEXCEPT
+  {
+    return executor_.context();
+  }
+
+  void dispatch(ASIO_MOVE_ARG(function) f)
+  {
+    executor_.dispatch(ASIO_MOVE_CAST(function)(f), allocator_);
+  }
+
+  void post(ASIO_MOVE_ARG(function) f)
+  {
+    executor_.post(ASIO_MOVE_CAST(function)(f), allocator_);
+  }
+
+  void defer(ASIO_MOVE_ARG(function) f)
+  {
+    executor_.defer(ASIO_MOVE_CAST(function)(f), allocator_);
+  }
+
+  type_id_result_type target_type() const ASIO_NOEXCEPT
+  {
+    return type_id<system_executor>();
+  }
+
+  void* target() ASIO_NOEXCEPT
+  {
+    return &executor_;
+  }
+
+  const void* target() const ASIO_NOEXCEPT
+  {
+    return &executor_;
+  }
+
+  bool equals(const impl_base* e) const ASIO_NOEXCEPT
+  {
+    return this == e;
+  }
+
+private:
+  system_executor executor_;
+  Allocator allocator_;
+};
+
+template <typename Executor>
+executor::executor(Executor e)
+  : impl_(impl<Executor, std::allocator<void> >::create(e))
+{
+}
+
+template <typename Executor, typename Allocator>
+executor::executor(allocator_arg_t, const Allocator& a, Executor e)
+  : impl_(impl<Executor, Allocator>::create(e, a))
+{
+}
+
+template <typename Function, typename Allocator>
+void executor::dispatch(ASIO_MOVE_ARG(Function) f,
+    const Allocator& a) const
+{
+  impl_base* i = get_impl();
+  if (i->fast_dispatch_)
+    system_executor().dispatch(ASIO_MOVE_CAST(Function)(f), a);
+  else
+    i->dispatch(function(ASIO_MOVE_CAST(Function)(f), a));
+}
+
+template <typename Function, typename Allocator>
+void executor::post(ASIO_MOVE_ARG(Function) f,
+    const Allocator& a) const
+{
+  get_impl()->post(function(ASIO_MOVE_CAST(Function)(f), a));
+}
+
+template <typename Function, typename Allocator>
+void executor::defer(ASIO_MOVE_ARG(Function) f,
+    const Allocator& a) const
+{
+  get_impl()->defer(function(ASIO_MOVE_CAST(Function)(f), a));
+}
+
+template <typename Executor>
+Executor* executor::target() ASIO_NOEXCEPT
+{
+  return impl_ && impl_->target_type() == type_id<Executor>()
+    ? static_cast<Executor*>(impl_->target()) : 0;
+}
+
+template <typename Executor>
+const Executor* executor::target() const ASIO_NOEXCEPT
+{
+  return impl_ && impl_->target_type() == type_id<Executor>()
+    ? static_cast<Executor*>(impl_->target()) : 0;
+}
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/impl/executor.ipp b/subprojects/asio/include/asio/impl/executor.ipp
new file mode 100644
index 000000000..4bd0dc5c8
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/executor.ipp
@@ -0,0 +1,38 @@
+//
+// impl/executor.ipp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_EXECUTOR_IPP
+#define ASIO_IMPL_EXECUTOR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+bad_executor::bad_executor() ASIO_NOEXCEPT
+{
+}
+
+const char* bad_executor::what() const ASIO_NOEXCEPT_OR_NOTHROW
+{
+  return "bad executor";
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_EXECUTOR_IPP
diff --git a/subprojects/asio/include/asio/impl/handler_alloc_hook.ipp b/subprojects/asio/include/asio/impl/handler_alloc_hook.ipp
new file mode 100644
index 000000000..909ddace8
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/handler_alloc_hook.ipp
@@ -0,0 +1,52 @@
+//
+// impl/handler_alloc_hook.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_HANDLER_ALLOC_HOOK_IPP
+#define ASIO_IMPL_HANDLER_ALLOC_HOOK_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/thread_context.hpp"
+#include "asio/detail/thread_info_base.hpp"
+#include "asio/handler_alloc_hook.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+void* asio_handler_allocate(std::size_t size, ...)
+{
+#if !defined(ASIO_DISABLE_SMALL_BLOCK_RECYCLING)
+  return detail::thread_info_base::allocate(
+      detail::thread_context::thread_call_stack::top(), size);
+#else // !defined(ASIO_DISABLE_SMALL_BLOCK_RECYCLING)
+  return ::operator new(size);
+#endif // !defined(ASIO_DISABLE_SMALL_BLOCK_RECYCLING)
+}
+
+void asio_handler_deallocate(void* pointer, std::size_t size, ...)
+{
+#if !defined(ASIO_DISABLE_SMALL_BLOCK_RECYCLING)
+  detail::thread_info_base::deallocate(
+      detail::thread_context::thread_call_stack::top(), pointer, size);
+#else // !defined(ASIO_DISABLE_SMALL_BLOCK_RECYCLING)
+  (void)size;
+  ::operator delete(pointer);
+#endif // !defined(ASIO_DISABLE_SMALL_BLOCK_RECYCLING)
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_HANDLER_ALLOC_HOOK_IPP
diff --git a/subprojects/asio/include/asio/impl/io_context.hpp b/subprojects/asio/include/asio/impl/io_context.hpp
new file mode 100644
index 000000000..5b6300f84
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/io_context.hpp
@@ -0,0 +1,343 @@
+//
+// impl/io_context.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_IO_CONTEXT_HPP
+#define ASIO_IMPL_IO_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/completion_handler.hpp"
+#include "asio/detail/executor_op.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/recycling_allocator.hpp"
+#include "asio/detail/service_registry.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename Service>
+inline Service& use_service(io_context& ioc)
+{
+  // Check that Service meets the necessary type requirements.
+  (void)static_cast<execution_context::service*>(static_cast<Service*>(0));
+  (void)static_cast<const execution_context::id*>(&Service::id);
+
+  return ioc.service_registry_->template use_service<Service>(ioc);
+}
+
+template <>
+inline detail::io_context_impl& use_service<detail::io_context_impl>(
+    io_context& ioc)
+{
+  return ioc.impl_;
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_io_context.hpp"
+#else
+# include "asio/detail/scheduler.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+inline io_context::executor_type
+io_context::get_executor() ASIO_NOEXCEPT
+{
+  return executor_type(*this);
+}
+
+#if defined(ASIO_HAS_CHRONO)
+
+template <typename Rep, typename Period>
+std::size_t io_context::run_for(
+    const chrono::duration<Rep, Period>& rel_time)
+{
+  return this->run_until(chrono::steady_clock::now() + rel_time);
+}
+
+template <typename Clock, typename Duration>
+std::size_t io_context::run_until(
+    const chrono::time_point<Clock, Duration>& abs_time)
+{
+  std::size_t n = 0;
+  while (this->run_one_until(abs_time))
+    if (n != (std::numeric_limits<std::size_t>::max)())
+      ++n;
+  return n;
+}
+
+template <typename Rep, typename Period>
+std::size_t io_context::run_one_for(
+    const chrono::duration<Rep, Period>& rel_time)
+{
+  return this->run_one_until(chrono::steady_clock::now() + rel_time);
+}
+
+template <typename Clock, typename Duration>
+std::size_t io_context::run_one_until(
+    const chrono::time_point<Clock, Duration>& abs_time)
+{
+  typename Clock::time_point now = Clock::now();
+  while (now < abs_time)
+  {
+    typename Clock::duration rel_time = abs_time - now;
+    if (rel_time > chrono::seconds(1))
+      rel_time = chrono::seconds(1);
+
+    asio::error_code ec;
+    std::size_t s = impl_.wait_one(
+        static_cast<long>(chrono::duration_cast<
+          chrono::microseconds>(rel_time).count()), ec);
+    asio::detail::throw_error(ec);
+
+    if (s || impl_.stopped())
+      return s;
+
+    now = Clock::now();
+  }
+
+  return 0;
+}
+
+#endif // defined(ASIO_HAS_CHRONO)
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+inline void io_context::reset()
+{
+  restart();
+}
+
+template <typename LegacyCompletionHandler>
+ASIO_INITFN_RESULT_TYPE(LegacyCompletionHandler, void ())
+io_context::dispatch(ASIO_MOVE_ARG(LegacyCompletionHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a LegacyCompletionHandler.
+  ASIO_LEGACY_COMPLETION_HANDLER_CHECK(
+      LegacyCompletionHandler, handler) type_check;
+
+  async_completion<LegacyCompletionHandler, void ()> init(handler);
+
+  if (impl_.can_dispatch())
+  {
+    detail::fenced_block b(detail::fenced_block::full);
+    asio_handler_invoke_helpers::invoke(
+        init.completion_handler, init.completion_handler);
+  }
+  else
+  {
+    // Allocate and construct an operation to wrap the handler.
+    typedef detail::completion_handler<
+      typename handler_type<LegacyCompletionHandler, void ()>::type> op;
+    typename op::ptr p = { detail::addressof(init.completion_handler),
+      op::ptr::allocate(init.completion_handler), 0 };
+    p.p = new (p.v) op(init.completion_handler);
+
+    ASIO_HANDLER_CREATION((*this, *p.p,
+          "io_context", this, 0, "dispatch"));
+
+    impl_.do_dispatch(p.p);
+    p.v = p.p = 0;
+  }
+
+  return init.result.get();
+}
+
+template <typename LegacyCompletionHandler>
+ASIO_INITFN_RESULT_TYPE(LegacyCompletionHandler, void ())
+io_context::post(ASIO_MOVE_ARG(LegacyCompletionHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a LegacyCompletionHandler.
+  ASIO_LEGACY_COMPLETION_HANDLER_CHECK(
+      LegacyCompletionHandler, handler) type_check;
+
+  async_completion<LegacyCompletionHandler, void ()> init(handler);
+
+  bool is_continuation =
+    asio_handler_cont_helpers::is_continuation(init.completion_handler);
+
+  // Allocate and construct an operation to wrap the handler.
+  typedef detail::completion_handler<
+    typename handler_type<LegacyCompletionHandler, void ()>::type> op;
+  typename op::ptr p = { detail::addressof(init.completion_handler),
+      op::ptr::allocate(init.completion_handler), 0 };
+  p.p = new (p.v) op(init.completion_handler);
+
+  ASIO_HANDLER_CREATION((*this, *p.p,
+        "io_context", this, 0, "post"));
+
+  impl_.post_immediate_completion(p.p, is_continuation);
+  p.v = p.p = 0;
+
+  return init.result.get();
+}
+
+template <typename Handler>
+#if defined(GENERATING_DOCUMENTATION)
+unspecified
+#else
+inline detail::wrapped_handler<io_context&, Handler>
+#endif
+io_context::wrap(Handler handler)
+{
+  return detail::wrapped_handler<io_context&, Handler>(*this, handler);
+}
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+inline io_context&
+io_context::executor_type::context() const ASIO_NOEXCEPT
+{
+  return io_context_;
+}
+
+inline void
+io_context::executor_type::on_work_started() const ASIO_NOEXCEPT
+{
+  io_context_.impl_.work_started();
+}
+
+inline void
+io_context::executor_type::on_work_finished() const ASIO_NOEXCEPT
+{
+  io_context_.impl_.work_finished();
+}
+
+template <typename Function, typename Allocator>
+void io_context::executor_type::dispatch(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Invoke immediately if we are already inside the thread pool.
+  if (io_context_.impl_.can_dispatch())
+  {
+    // Make a local, non-const copy of the function.
+    function_type tmp(ASIO_MOVE_CAST(Function)(f));
+
+    detail::fenced_block b(detail::fenced_block::full);
+    asio_handler_invoke_helpers::invoke(tmp, tmp);
+    return;
+  }
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator, detail::operation> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((this->context(), *p.p,
+        "io_context", &this->context(), 0, "dispatch"));
+
+  io_context_.impl_.post_immediate_completion(p.p, false);
+  p.v = p.p = 0;
+}
+
+template <typename Function, typename Allocator>
+void io_context::executor_type::post(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator, detail::operation> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((this->context(), *p.p,
+        "io_context", &this->context(), 0, "post"));
+
+  io_context_.impl_.post_immediate_completion(p.p, false);
+  p.v = p.p = 0;
+}
+
+template <typename Function, typename Allocator>
+void io_context::executor_type::defer(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator, detail::operation> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((this->context(), *p.p,
+        "io_context", &this->context(), 0, "defer"));
+
+  io_context_.impl_.post_immediate_completion(p.p, true);
+  p.v = p.p = 0;
+}
+
+inline bool
+io_context::executor_type::running_in_this_thread() const ASIO_NOEXCEPT
+{
+  return io_context_.impl_.can_dispatch();
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+inline io_context::work::work(asio::io_context& io_context)
+  : io_context_impl_(io_context.impl_)
+{
+  io_context_impl_.work_started();
+}
+
+inline io_context::work::work(const work& other)
+  : io_context_impl_(other.io_context_impl_)
+{
+  io_context_impl_.work_started();
+}
+
+inline io_context::work::~work()
+{
+  io_context_impl_.work_finished();
+}
+
+inline asio::io_context& io_context::work::get_io_context()
+{
+  return static_cast<asio::io_context&>(io_context_impl_.context());
+}
+
+inline asio::io_context& io_context::work::get_io_service()
+{
+  return static_cast<asio::io_context&>(io_context_impl_.context());
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+inline asio::io_context& io_context::service::get_io_context()
+{
+  return static_cast<asio::io_context&>(context());
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+inline asio::io_context& io_context::service::get_io_service()
+{
+  return static_cast<asio::io_context&>(context());
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_IO_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/impl/io_context.ipp b/subprojects/asio/include/asio/impl/io_context.ipp
new file mode 100644
index 000000000..7eb467d26
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/io_context.ipp
@@ -0,0 +1,174 @@
+//
+// impl/io_context.ipp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_IO_CONTEXT_IPP
+#define ASIO_IMPL_IO_CONTEXT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/concurrency_hint.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/scoped_ptr.hpp"
+#include "asio/detail/service_registry.hpp"
+#include "asio/detail/throw_error.hpp"
+
+#if defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_io_context.hpp"
+#else
+# include "asio/detail/scheduler.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+io_context::io_context()
+  : impl_(add_impl(new impl_type(*this, ASIO_CONCURRENCY_HINT_DEFAULT)))
+{
+}
+
+io_context::io_context(int concurrency_hint)
+  : impl_(add_impl(new impl_type(*this, concurrency_hint == 1
+          ? ASIO_CONCURRENCY_HINT_1 : concurrency_hint)))
+{
+}
+
+io_context::impl_type& io_context::add_impl(io_context::impl_type* impl)
+{
+  asio::detail::scoped_ptr<impl_type> scoped_impl(impl);
+  asio::add_service<impl_type>(*this, scoped_impl.get());
+  return *scoped_impl.release();
+}
+
+io_context::~io_context()
+{
+}
+
+io_context::count_type io_context::run()
+{
+  asio::error_code ec;
+  count_type s = impl_.run(ec);
+  asio::detail::throw_error(ec);
+  return s;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+io_context::count_type io_context::run(asio::error_code& ec)
+{
+  return impl_.run(ec);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+io_context::count_type io_context::run_one()
+{
+  asio::error_code ec;
+  count_type s = impl_.run_one(ec);
+  asio::detail::throw_error(ec);
+  return s;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+io_context::count_type io_context::run_one(asio::error_code& ec)
+{
+  return impl_.run_one(ec);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+io_context::count_type io_context::poll()
+{
+  asio::error_code ec;
+  count_type s = impl_.poll(ec);
+  asio::detail::throw_error(ec);
+  return s;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+io_context::count_type io_context::poll(asio::error_code& ec)
+{
+  return impl_.poll(ec);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+io_context::count_type io_context::poll_one()
+{
+  asio::error_code ec;
+  count_type s = impl_.poll_one(ec);
+  asio::detail::throw_error(ec);
+  return s;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+io_context::count_type io_context::poll_one(asio::error_code& ec)
+{
+  return impl_.poll_one(ec);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+void io_context::stop()
+{
+  impl_.stop();
+}
+
+bool io_context::stopped() const
+{
+  return impl_.stopped();
+}
+
+void io_context::restart()
+{
+  impl_.restart();
+}
+
+io_context::service::service(asio::io_context& owner)
+  : execution_context::service(owner)
+{
+}
+
+io_context::service::~service()
+{
+}
+
+void io_context::service::shutdown()
+{
+#if !defined(ASIO_NO_DEPRECATED)
+  shutdown_service();
+#endif // !defined(ASIO_NO_DEPRECATED)
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+void io_context::service::shutdown_service()
+{
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+void io_context::service::notify_fork(io_context::fork_event ev)
+{
+#if !defined(ASIO_NO_DEPRECATED)
+  fork_service(ev);
+#else // !defined(ASIO_NO_DEPRECATED)
+  (void)ev;
+#endif // !defined(ASIO_NO_DEPRECATED)
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+void io_context::service::fork_service(io_context::fork_event)
+{
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_IO_CONTEXT_IPP
diff --git a/subprojects/asio/include/asio/impl/post.hpp b/subprojects/asio/include/asio/impl/post.hpp
new file mode 100644
index 000000000..55389532b
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/post.hpp
@@ -0,0 +1,77 @@
+//
+// impl/post.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_POST_HPP
+#define ASIO_IMPL_POST_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/detail/work_dispatcher.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) post(
+    ASIO_MOVE_ARG(CompletionToken) token)
+{
+  typedef ASIO_HANDLER_TYPE(CompletionToken, void()) handler;
+
+  async_completion<CompletionToken, void()> init(token);
+
+  typename associated_executor<handler>::type ex(
+      (get_associated_executor)(init.completion_handler));
+
+  typename associated_allocator<handler>::type alloc(
+      (get_associated_allocator)(init.completion_handler));
+
+  ex.post(ASIO_MOVE_CAST(handler)(init.completion_handler), alloc);
+
+  return init.result.get();
+}
+
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) post(
+    const Executor& ex, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_executor<Executor>::value>::type*)
+{
+  typedef ASIO_HANDLER_TYPE(CompletionToken, void()) handler;
+
+  async_completion<CompletionToken, void()> init(token);
+
+  typename associated_allocator<handler>::type alloc(
+      (get_associated_allocator)(init.completion_handler));
+
+  ex.post(detail::work_dispatcher<handler>(init.completion_handler), alloc);
+
+  return init.result.get();
+}
+
+template <typename ExecutionContext, typename CompletionToken>
+inline ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) post(
+    ExecutionContext& ctx, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type*)
+{
+  return (post)(ctx.get_executor(),
+      ASIO_MOVE_CAST(CompletionToken)(token));
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_POST_HPP
diff --git a/subprojects/asio/include/asio/impl/read.hpp b/subprojects/asio/include/asio/impl/read.hpp
new file mode 100644
index 000000000..603a7a9b1
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/read.hpp
@@ -0,0 +1,715 @@
+//
+// impl/read.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_READ_HPP
+#define ASIO_IMPL_READ_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <algorithm>
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/buffer.hpp"
+#include "asio/completion_condition.hpp"
+#include "asio/detail/array_fwd.hpp"
+#include "asio/detail/base_from_completion_cond.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/consuming_buffers.hpp"
+#include "asio/detail/dependent_type.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  template <typename SyncReadStream, typename MutableBufferSequence,
+      typename MutableBufferIterator, typename CompletionCondition>
+  std::size_t read_buffer_sequence(SyncReadStream& s,
+      const MutableBufferSequence& buffers, const MutableBufferIterator&,
+      CompletionCondition completion_condition, asio::error_code& ec)
+  {
+    ec = asio::error_code();
+    asio::detail::consuming_buffers<mutable_buffer,
+        MutableBufferSequence, MutableBufferIterator> tmp(buffers);
+    while (!tmp.empty())
+    {
+      if (std::size_t max_size = detail::adapt_completion_condition_result(
+            completion_condition(ec, tmp.total_consumed())))
+        tmp.consume(s.read_some(tmp.prepare(max_size), ec));
+      else
+        break;
+    }
+    return tmp.total_consumed();;
+  }
+} // namespace detail
+
+template <typename SyncReadStream, typename MutableBufferSequence,
+    typename CompletionCondition>
+std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type*)
+{
+  return detail::read_buffer_sequence(s, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition, ec);
+}
+
+template <typename SyncReadStream, typename MutableBufferSequence>
+inline std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read(s, buffers, transfer_all(), ec);
+  asio::detail::throw_error(ec, "read");
+  return bytes_transferred;
+}
+
+template <typename SyncReadStream, typename MutableBufferSequence>
+inline std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type*)
+{
+  return read(s, buffers, transfer_all(), ec);
+}
+
+template <typename SyncReadStream, typename MutableBufferSequence,
+    typename CompletionCondition>
+inline std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read(s, buffers, completion_condition, ec);
+  asio::detail::throw_error(ec, "read");
+  return bytes_transferred;
+}
+
+template <typename SyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition>
+std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  typename decay<DynamicBuffer>::type b(
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers));
+
+  ec = asio::error_code();
+  std::size_t total_transferred = 0;
+  std::size_t max_size = detail::adapt_completion_condition_result(
+        completion_condition(ec, total_transferred));
+  std::size_t bytes_available = std::min<std::size_t>(
+        std::max<std::size_t>(512, b.capacity() - b.size()),
+        std::min<std::size_t>(max_size, b.max_size() - b.size()));
+  while (bytes_available > 0)
+  {
+    std::size_t bytes_transferred = s.read_some(b.prepare(bytes_available), ec);
+    b.commit(bytes_transferred);
+    total_transferred += bytes_transferred;
+    max_size = detail::adapt_completion_condition_result(
+          completion_condition(ec, total_transferred));
+    bytes_available = std::min<std::size_t>(
+          std::max<std::size_t>(512, b.capacity() - b.size()),
+          std::min<std::size_t>(max_size, b.max_size() - b.size()));
+  }
+  return total_transferred;
+}
+
+template <typename SyncReadStream, typename DynamicBuffer>
+inline std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers), transfer_all(), ec);
+  asio::detail::throw_error(ec, "read");
+  return bytes_transferred;
+}
+
+template <typename SyncReadStream, typename DynamicBuffer>
+inline std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  return read(s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      transfer_all(), ec);
+}
+
+template <typename SyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition>
+inline std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      completion_condition, ec);
+  asio::detail::throw_error(ec, "read");
+  return bytes_transferred;
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename SyncReadStream, typename Allocator,
+    typename CompletionCondition>
+inline std::size_t read(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, asio::error_code& ec)
+{
+  return read(s, basic_streambuf_ref<Allocator>(b), completion_condition, ec);
+}
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b)
+{
+  return read(s, basic_streambuf_ref<Allocator>(b));
+}
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    asio::error_code& ec)
+{
+  return read(s, basic_streambuf_ref<Allocator>(b), ec);
+}
+
+template <typename SyncReadStream, typename Allocator,
+    typename CompletionCondition>
+inline std::size_t read(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition)
+{
+  return read(s, basic_streambuf_ref<Allocator>(b), completion_condition);
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+namespace detail
+{
+  template <typename AsyncReadStream, typename MutableBufferSequence,
+      typename MutableBufferIterator, typename CompletionCondition,
+      typename ReadHandler>
+  class read_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_op(AsyncReadStream& stream, const MutableBufferSequence& buffers,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        stream_(stream),
+        buffers_(buffers),
+        start_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_op(const read_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        stream_(other.stream_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_op(read_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        stream_(other.stream_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t max_size;
+      switch (start_ = start)
+      {
+        case 1:
+        max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        do
+        {
+          stream_.async_read_some(buffers_.prepare(max_size),
+              ASIO_MOVE_CAST(read_op)(*this));
+          return; default:
+          buffers_.consume(bytes_transferred);
+          if ((!ec && bytes_transferred == 0) || buffers_.empty())
+            break;
+          max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        } while (max_size > 0);
+
+        handler_(ec, buffers_.total_consumed());
+      }
+    }
+
+  //private:
+    AsyncReadStream& stream_;
+    asio::detail::consuming_buffers<mutable_buffer,
+        MutableBufferSequence, MutableBufferIterator> buffers_;
+    int start_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncReadStream, typename MutableBufferSequence,
+      typename MutableBufferIterator, typename CompletionCondition,
+      typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_op<AsyncReadStream, MutableBufferSequence, MutableBufferIterator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename MutableBufferSequence,
+      typename MutableBufferIterator, typename CompletionCondition,
+      typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_op<AsyncReadStream, MutableBufferSequence, MutableBufferIterator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename MutableBufferSequence,
+      typename MutableBufferIterator, typename CompletionCondition,
+      typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_op<AsyncReadStream, MutableBufferSequence, MutableBufferIterator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_op<AsyncReadStream, MutableBufferSequence, MutableBufferIterator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_op<AsyncReadStream, MutableBufferSequence, MutableBufferIterator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename MutableBufferSequence,
+      typename MutableBufferIterator, typename CompletionCondition,
+      typename ReadHandler>
+  inline void start_read_buffer_sequence_op(AsyncReadStream& stream,
+      const MutableBufferSequence& buffers, const MutableBufferIterator&,
+      CompletionCondition completion_condition, ReadHandler& handler)
+  {
+    detail::read_op<AsyncReadStream, MutableBufferSequence,
+      MutableBufferIterator, CompletionCondition, ReadHandler>(
+        stream, buffers, completion_condition, handler)(
+          asio::error_code(), 0, 1);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename MutableBufferSequence,
+    typename MutableBufferIterator, typename CompletionCondition,
+    typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::read_op<AsyncReadStream, MutableBufferSequence,
+      MutableBufferIterator, CompletionCondition, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::read_op<AsyncReadStream, MutableBufferSequence,
+        MutableBufferIterator, CompletionCondition, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncReadStream, typename MutableBufferSequence,
+    typename MutableBufferIterator, typename CompletionCondition,
+    typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::read_op<AsyncReadStream, MutableBufferSequence,
+      MutableBufferIterator, CompletionCondition, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::read_op<AsyncReadStream, MutableBufferSequence,
+        MutableBufferIterator, CompletionCondition, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename MutableBufferSequence,
+    typename CompletionCondition, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_read_buffer_sequence_op(s, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition,
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+template <typename AsyncReadStream, typename MutableBufferSequence,
+    typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, const MutableBufferSequence& buffers,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_read_buffer_sequence_op(s, buffers,
+      asio::buffer_sequence_begin(buffers), transfer_all(),
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+namespace detail
+{
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename CompletionCondition, typename ReadHandler>
+  class read_dynbuf_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    template <typename BufferSequence>
+    read_dynbuf_op(AsyncReadStream& stream,
+        ASIO_MOVE_ARG(BufferSequence) buffers,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        stream_(stream),
+        buffers_(ASIO_MOVE_CAST(BufferSequence)(buffers)),
+        start_(0),
+        total_transferred_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_dynbuf_op(const read_dynbuf_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        stream_(other.stream_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_dynbuf_op(read_dynbuf_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        stream_(other.stream_),
+        buffers_(ASIO_MOVE_CAST(DynamicBuffer)(other.buffers_)),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t max_size, bytes_available;
+      switch (start_ = start)
+      {
+        case 1:
+        max_size = this->check_for_completion(ec, total_transferred_);
+        bytes_available = std::min<std::size_t>(
+              std::max<std::size_t>(512,
+                buffers_.capacity() - buffers_.size()),
+              std::min<std::size_t>(max_size,
+                buffers_.max_size() - buffers_.size()));
+        for (;;)
+        {
+          stream_.async_read_some(buffers_.prepare(bytes_available),
+              ASIO_MOVE_CAST(read_dynbuf_op)(*this));
+          return; default:
+          total_transferred_ += bytes_transferred;
+          buffers_.commit(bytes_transferred);
+          max_size = this->check_for_completion(ec, total_transferred_);
+          bytes_available = std::min<std::size_t>(
+                std::max<std::size_t>(512,
+                  buffers_.capacity() - buffers_.size()),
+                std::min<std::size_t>(max_size,
+                  buffers_.max_size() - buffers_.size()));
+          if ((!ec && bytes_transferred == 0) || bytes_available == 0)
+            break;
+        }
+
+        handler_(ec, static_cast<const std::size_t&>(total_transferred_));
+      }
+    }
+
+  //private:
+    AsyncReadStream& stream_;
+    DynamicBuffer buffers_;
+    int start_;
+    std::size_t total_transferred_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename CompletionCondition, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_dynbuf_op<AsyncReadStream, DynamicBuffer,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_dynbuf_op<AsyncReadStream, DynamicBuffer,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename CompletionCondition, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_dynbuf_op<AsyncReadStream, DynamicBuffer,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename CompletionCondition,
+      typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_dynbuf_op<AsyncReadStream, DynamicBuffer,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename CompletionCondition,
+      typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_dynbuf_op<AsyncReadStream, DynamicBuffer,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition, typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::read_dynbuf_op<AsyncReadStream,
+      DynamicBuffer, CompletionCondition, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::read_dynbuf_op<AsyncReadStream,
+        DynamicBuffer, CompletionCondition, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition, typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::read_dynbuf_op<AsyncReadStream,
+      DynamicBuffer, CompletionCondition, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::read_dynbuf_op<AsyncReadStream,
+        DynamicBuffer, CompletionCondition, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  return async_read(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      transfer_all(), ASIO_MOVE_CAST(ReadHandler)(handler));
+}
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::read_dynbuf_op<AsyncReadStream,
+    typename decay<DynamicBuffer>::type,
+      CompletionCondition, ASIO_HANDLER_TYPE(
+        ReadHandler, void (asio::error_code, std::size_t))>(
+          s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+            completion_condition, init.completion_handler)(
+              asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, basic_streambuf<Allocator>& b,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  return async_read(s, basic_streambuf_ref<Allocator>(b),
+      ASIO_MOVE_CAST(ReadHandler)(handler));
+}
+
+template <typename AsyncReadStream, typename Allocator,
+    typename CompletionCondition, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  return async_read(s, basic_streambuf_ref<Allocator>(b),
+      completion_condition, ASIO_MOVE_CAST(ReadHandler)(handler));
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_READ_HPP
diff --git a/subprojects/asio/include/asio/impl/read_at.hpp b/subprojects/asio/include/asio/impl/read_at.hpp
new file mode 100644
index 000000000..d736d4d31
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/read_at.hpp
@@ -0,0 +1,640 @@
+//
+// impl/read_at.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_READ_AT_HPP
+#define ASIO_IMPL_READ_AT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <algorithm>
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/buffer.hpp"
+#include "asio/completion_condition.hpp"
+#include "asio/detail/array_fwd.hpp"
+#include "asio/detail/base_from_completion_cond.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/consuming_buffers.hpp"
+#include "asio/detail/dependent_type.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
+      typename MutableBufferIterator, typename CompletionCondition>
+  std::size_t read_at_buffer_sequence(SyncRandomAccessReadDevice& d,
+      uint64_t offset, const MutableBufferSequence& buffers,
+      const MutableBufferIterator&, CompletionCondition completion_condition,
+      asio::error_code& ec)
+  {
+    ec = asio::error_code();
+    asio::detail::consuming_buffers<mutable_buffer,
+        MutableBufferSequence, MutableBufferIterator> tmp(buffers);
+    while (!tmp.empty())
+    {
+      if (std::size_t max_size = detail::adapt_completion_condition_result(
+            completion_condition(ec, tmp.total_consumed())))
+      {
+        tmp.consume(d.read_some_at(offset + tmp.total_consumed(),
+              tmp.prepare(max_size), ec));
+      }
+      else
+        break;
+    }
+    return tmp.total_consumed();;
+  }
+} // namespace detail
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec)
+{
+  return detail::read_at_buffer_sequence(d, offset, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition, ec);
+}
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, buffers, transfer_all(), ec);
+  asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    asio::error_code& ec)
+{
+  return read_at(d, offset, buffers, transfer_all(), ec);
+}
+
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, buffers, completion_condition, ec);
+  asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename SyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, asio::error_code& ec)
+{
+  ec = asio::error_code();
+  std::size_t total_transferred = 0;
+  std::size_t max_size = detail::adapt_completion_condition_result(
+        completion_condition(ec, total_transferred));
+  std::size_t bytes_available = read_size_helper(b, max_size);
+  while (bytes_available > 0)
+  {
+    std::size_t bytes_transferred = d.read_some_at(
+        offset + total_transferred, b.prepare(bytes_available), ec);
+    b.commit(bytes_transferred);
+    total_transferred += bytes_transferred;
+    max_size = detail::adapt_completion_condition_result(
+          completion_condition(ec, total_transferred));
+    bytes_available = read_size_helper(b, max_size);
+  }
+  return total_transferred;
+}
+
+template <typename SyncRandomAccessReadDevice, typename Allocator>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, b, transfer_all(), ec);
+  asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+template <typename SyncRandomAccessReadDevice, typename Allocator>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    asio::error_code& ec)
+{
+  return read_at(d, offset, b, transfer_all(), ec);
+}
+
+template <typename SyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition>
+inline std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_at(
+      d, offset, b, completion_condition, ec);
+  asio::detail::throw_error(ec, "read_at");
+  return bytes_transferred;
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+namespace detail
+{
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  class read_at_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_at_op(AsyncRandomAccessReadDevice& device,
+        uint64_t offset, const MutableBufferSequence& buffers,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        buffers_(buffers),
+        start_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_at_op(const read_at_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_at_op(read_at_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t max_size;
+      switch (start_ = start)
+      {
+        case 1:
+        max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        do
+        {
+          device_.async_read_some_at(
+              offset_ + buffers_.total_consumed(), buffers_.prepare(max_size),
+              ASIO_MOVE_CAST(read_at_op)(*this));
+          return; default:
+          buffers_.consume(bytes_transferred);
+          if ((!ec && bytes_transferred == 0) || buffers_.empty())
+            break;
+          max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        } while (max_size > 0);
+
+        handler_(ec, buffers_.total_consumed());
+      }
+    }
+
+  //private:
+    AsyncRandomAccessReadDevice& device_;
+    uint64_t offset_;
+    asio::detail::consuming_buffers<mutable_buffer,
+        MutableBufferSequence, MutableBufferIterator> buffers_;
+    int start_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+        MutableBufferIterator, CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice,
+      typename MutableBufferSequence, typename MutableBufferIterator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void start_read_at_buffer_sequence_op(AsyncRandomAccessReadDevice& d,
+      uint64_t offset, const MutableBufferSequence& buffers,
+      const MutableBufferIterator&, CompletionCondition completion_condition,
+      ReadHandler& handler)
+  {
+    detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+      MutableBufferIterator, CompletionCondition, ReadHandler>(
+        d, offset, buffers, completion_condition, handler)(
+          asio::error_code(), 0, 1);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncRandomAccessReadDevice,
+    typename MutableBufferSequence, typename MutableBufferIterator,
+    typename CompletionCondition, typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+    MutableBufferIterator, CompletionCondition, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::read_at_op<AsyncRandomAccessReadDevice,
+      MutableBufferSequence, MutableBufferIterator,
+      CompletionCondition, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncRandomAccessReadDevice,
+    typename MutableBufferSequence, typename MutableBufferIterator,
+    typename CompletionCondition, typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::read_at_op<AsyncRandomAccessReadDevice, MutableBufferSequence,
+    MutableBufferIterator, CompletionCondition, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::read_at_op<AsyncRandomAccessReadDevice,
+      MutableBufferSequence, MutableBufferIterator,
+      CompletionCondition, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_read_at_buffer_sequence_op(d, offset, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition,
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_read_at_buffer_sequence_op(d, offset, buffers,
+      asio::buffer_sequence_begin(buffers), transfer_all(),
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+namespace detail
+{
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  class read_at_streambuf_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    read_at_streambuf_op(AsyncRandomAccessReadDevice& device,
+        uint64_t offset, basic_streambuf<Allocator>& streambuf,
+        CompletionCondition completion_condition, ReadHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        streambuf_(streambuf),
+        start_(0),
+        total_transferred_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_at_streambuf_op(const read_at_streambuf_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        streambuf_(other.streambuf_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_at_streambuf_op(read_at_streambuf_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        streambuf_(other.streambuf_),
+        start_(other.start_),
+        total_transferred_(other.total_transferred_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t max_size, bytes_available;
+      switch (start_ = start)
+      {
+        case 1:
+        max_size = this->check_for_completion(ec, total_transferred_);
+        bytes_available = read_size_helper(streambuf_, max_size);
+        for (;;)
+        {
+          device_.async_read_some_at(offset_ + total_transferred_,
+              streambuf_.prepare(bytes_available),
+              ASIO_MOVE_CAST(read_at_streambuf_op)(*this));
+          return; default:
+          total_transferred_ += bytes_transferred;
+          streambuf_.commit(bytes_transferred);
+          max_size = this->check_for_completion(ec, total_transferred_);
+          bytes_available = read_size_helper(streambuf_, max_size);
+          if ((!ec && bytes_transferred == 0) || bytes_available == 0)
+            break;
+        }
+
+        handler_(ec, static_cast<const std::size_t&>(total_transferred_));
+      }
+    }
+
+  //private:
+    AsyncRandomAccessReadDevice& device_;
+    uint64_t offset_;
+    asio::basic_streambuf<Allocator>& streambuf_;
+    int start_;
+    std::size_t total_transferred_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessReadDevice, typename Allocator,
+      typename CompletionCondition, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename Allocator, typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessReadDevice,
+      typename Allocator, typename CompletionCondition, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+        CompletionCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition, typename ReadHandler, typename Allocator1>
+struct associated_allocator<
+    detail::read_at_streambuf_op<AsyncRandomAccessReadDevice,
+      Allocator, CompletionCondition, ReadHandler>,
+    Allocator1>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator1>::type type;
+
+  static type get(
+      const detail::read_at_streambuf_op<AsyncRandomAccessReadDevice,
+        Allocator, CompletionCondition, ReadHandler>& h,
+      const Allocator1& a = Allocator1()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator1>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncRandomAccessReadDevice, typename Executor,
+    typename CompletionCondition, typename ReadHandler, typename Executor1>
+struct associated_executor<
+    detail::read_at_streambuf_op<AsyncRandomAccessReadDevice,
+      Executor, CompletionCondition, ReadHandler>,
+    Executor1>
+{
+  typedef typename associated_executor<ReadHandler, Executor1>::type type;
+
+  static type get(
+      const detail::read_at_streambuf_op<AsyncRandomAccessReadDevice,
+        Executor, CompletionCondition, ReadHandler>& h,
+      const Executor1& ex = Executor1()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor1>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+    CompletionCondition, ASIO_HANDLER_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))>(
+        d, offset, b, completion_condition, init.completion_handler)(
+          asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+template <typename AsyncRandomAccessReadDevice, typename Allocator,
+    typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::read_at_streambuf_op<AsyncRandomAccessReadDevice, Allocator,
+    detail::transfer_all_t, ASIO_HANDLER_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))>(
+        d, offset, b, transfer_all(), init.completion_handler)(
+          asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_READ_AT_HPP
diff --git a/subprojects/asio/include/asio/impl/read_until.hpp b/subprojects/asio/include/asio/impl/read_until.hpp
new file mode 100644
index 000000000..1a093cf03
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/read_until.hpp
@@ -0,0 +1,1502 @@
+//
+// impl/read_until.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_READ_UNTIL_HPP
+#define ASIO_IMPL_READ_UNTIL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <algorithm>
+#include <string>
+#include <vector>
+#include <utility>
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/buffer.hpp"
+#include "asio/buffers_iterator.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/limits.hpp"
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename SyncReadStream, typename DynamicBuffer>
+inline std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers, char delim)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_until(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers), delim, ec);
+  asio::detail::throw_error(ec, "read_until");
+  return bytes_transferred;
+}
+
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    char delim, asio::error_code& ec)
+{
+  typename decay<DynamicBuffer>::type b(
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers));
+
+  std::size_t search_position = 0;
+  for (;;)
+  {
+    // Determine the range of the data to be searched.
+    typedef typename DynamicBuffer::const_buffers_type buffers_type;
+    typedef buffers_iterator<buffers_type> iterator;
+    buffers_type data_buffers = b.data();
+    iterator begin = iterator::begin(data_buffers);
+    iterator start_pos = begin + search_position;
+    iterator end = iterator::end(data_buffers);
+
+    // Look for a match.
+    iterator iter = std::find(start_pos, end, delim);
+    if (iter != end)
+    {
+      // Found a match. We're done.
+      ec = asio::error_code();
+      return iter - begin + 1;
+    }
+    else
+    {
+      // No match. Next search can start with the new data.
+      search_position = end - begin;
+    }
+
+    // Check if buffer is full.
+    if (b.size() == b.max_size())
+    {
+      ec = error::not_found;
+      return 0;
+    }
+
+    // Need more data.
+    std::size_t bytes_to_read = std::min<std::size_t>(
+          std::max<std::size_t>(512, b.capacity() - b.size()),
+          std::min<std::size_t>(65536, b.max_size() - b.size()));
+    b.commit(s.read_some(b.prepare(bytes_to_read), ec));
+    if (ec)
+      return 0;
+  }
+}
+
+template <typename SyncReadStream, typename DynamicBuffer>
+inline std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_STRING_VIEW_PARAM delim)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_until(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers), delim, ec);
+  asio::detail::throw_error(ec, "read_until");
+  return bytes_transferred;
+}
+
+namespace detail
+{
+  // Algorithm that finds a subsequence of equal values in a sequence. Returns
+  // (iterator,true) if a full match was found, in which case the iterator
+  // points to the beginning of the match. Returns (iterator,false) if a
+  // partial match was found at the end of the first sequence, in which case
+  // the iterator points to the beginning of the partial match. Returns
+  // (last1,false) if no full or partial match was found.
+  template <typename Iterator1, typename Iterator2>
+  std::pair<Iterator1, bool> partial_search(
+      Iterator1 first1, Iterator1 last1, Iterator2 first2, Iterator2 last2)
+  {
+    for (Iterator1 iter1 = first1; iter1 != last1; ++iter1)
+    {
+      Iterator1 test_iter1 = iter1;
+      Iterator2 test_iter2 = first2;
+      for (;; ++test_iter1, ++test_iter2)
+      {
+        if (test_iter2 == last2)
+          return std::make_pair(iter1, true);
+        if (test_iter1 == last1)
+        {
+          if (test_iter2 != first2)
+            return std::make_pair(iter1, false);
+          else
+            break;
+        }
+        if (*test_iter1 != *test_iter2)
+          break;
+      }
+    }
+    return std::make_pair(last1, false);
+  }
+} // namespace detail
+
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_STRING_VIEW_PARAM delim, asio::error_code& ec)
+{
+  typename decay<DynamicBuffer>::type b(
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers));
+
+  std::size_t search_position = 0;
+  for (;;)
+  {
+    // Determine the range of the data to be searched.
+    typedef typename DynamicBuffer::const_buffers_type buffers_type;
+    typedef buffers_iterator<buffers_type> iterator;
+    buffers_type data_buffers = b.data();
+    iterator begin = iterator::begin(data_buffers);
+    iterator start_pos = begin + search_position;
+    iterator end = iterator::end(data_buffers);
+
+    // Look for a match.
+    std::pair<iterator, bool> result = detail::partial_search(
+        start_pos, end, delim.begin(), delim.end());
+    if (result.first != end)
+    {
+      if (result.second)
+      {
+        // Full match. We're done.
+        ec = asio::error_code();
+        return result.first - begin + delim.length();
+      }
+      else
+      {
+        // Partial match. Next search needs to start from beginning of match.
+        search_position = result.first - begin;
+      }
+    }
+    else
+    {
+      // No match. Next search can start with the new data.
+      search_position = end - begin;
+    }
+
+    // Check if buffer is full.
+    if (b.size() == b.max_size())
+    {
+      ec = error::not_found;
+      return 0;
+    }
+
+    // Need more data.
+    std::size_t bytes_to_read = std::min<std::size_t>(
+          std::max<std::size_t>(512, b.capacity() - b.size()),
+          std::min<std::size_t>(65536, b.max_size() - b.size()));
+    b.commit(s.read_some(b.prepare(bytes_to_read), ec));
+    if (ec)
+      return 0;
+  }
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if defined(ASIO_HAS_BOOST_REGEX)
+
+template <typename SyncReadStream, typename DynamicBuffer>
+inline std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    const boost::regex& expr)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_until(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers), expr, ec);
+  asio::detail::throw_error(ec, "read_until");
+  return bytes_transferred;
+}
+
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    const boost::regex& expr, asio::error_code& ec)
+{
+  typename decay<DynamicBuffer>::type b(
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers));
+
+  std::size_t search_position = 0;
+  for (;;)
+  {
+    // Determine the range of the data to be searched.
+    typedef typename DynamicBuffer::const_buffers_type buffers_type;
+    typedef buffers_iterator<buffers_type> iterator;
+    buffers_type data_buffers = b.data();
+    iterator begin = iterator::begin(data_buffers);
+    iterator start_pos = begin + search_position;
+    iterator end = iterator::end(data_buffers);
+
+    // Look for a match.
+    boost::match_results<iterator,
+      typename std::vector<boost::sub_match<iterator> >::allocator_type>
+        match_results;
+    if (regex_search(start_pos, end, match_results, expr,
+          boost::match_default | boost::match_partial))
+    {
+      if (match_results[0].matched)
+      {
+        // Full match. We're done.
+        ec = asio::error_code();
+        return match_results[0].second - begin;
+      }
+      else
+      {
+        // Partial match. Next search needs to start from beginning of match.
+        search_position = match_results[0].first - begin;
+      }
+    }
+    else
+    {
+      // No match. Next search can start with the new data.
+      search_position = end - begin;
+    }
+
+    // Check if buffer is full.
+    if (b.size() == b.max_size())
+    {
+      ec = error::not_found;
+      return 0;
+    }
+
+    // Need more data.
+    std::size_t bytes_to_read = std::min<std::size_t>(
+          std::max<std::size_t>(512, b.capacity() - b.size()),
+          std::min<std::size_t>(65536, b.max_size() - b.size()));
+    b.commit(s.read_some(b.prepare(bytes_to_read), ec));
+    if (ec)
+      return 0;
+  }
+}
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+
+template <typename SyncReadStream,
+    typename DynamicBuffer, typename MatchCondition>
+inline std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    MatchCondition match_condition,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = read_until(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      match_condition, ec);
+  asio::detail::throw_error(ec, "read_until");
+  return bytes_transferred;
+}
+
+template <typename SyncReadStream,
+    typename DynamicBuffer, typename MatchCondition>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    MatchCondition match_condition, asio::error_code& ec,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type*)
+{
+  typename decay<DynamicBuffer>::type b(
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers));
+
+  std::size_t search_position = 0;
+  for (;;)
+  {
+    // Determine the range of the data to be searched.
+    typedef typename DynamicBuffer::const_buffers_type buffers_type;
+    typedef buffers_iterator<buffers_type> iterator;
+    buffers_type data_buffers = b.data();
+    iterator begin = iterator::begin(data_buffers);
+    iterator start_pos = begin + search_position;
+    iterator end = iterator::end(data_buffers);
+
+    // Look for a match.
+    std::pair<iterator, bool> result = match_condition(start_pos, end);
+    if (result.second)
+    {
+      // Full match. We're done.
+      ec = asio::error_code();
+      return result.first - begin;
+    }
+    else if (result.first != end)
+    {
+      // Partial match. Next search needs to start from beginning of match.
+      search_position = result.first - begin;
+    }
+    else
+    {
+      // No match. Next search can start with the new data.
+      search_position = end - begin;
+    }
+
+    // Check if buffer is full.
+    if (b.size() == b.max_size())
+    {
+      ec = error::not_found;
+      return 0;
+    }
+
+    // Need more data.
+    std::size_t bytes_to_read = std::min<std::size_t>(
+          std::max<std::size_t>(512, b.capacity() - b.size()),
+          std::min<std::size_t>(65536, b.max_size() - b.size()));
+    b.commit(s.read_some(b.prepare(bytes_to_read), ec));
+    if (ec)
+      return 0;
+  }
+}
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, char delim)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), delim);
+}
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, char delim,
+    asio::error_code& ec)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), delim, ec);
+}
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    ASIO_STRING_VIEW_PARAM delim)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), delim);
+}
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    ASIO_STRING_VIEW_PARAM delim, asio::error_code& ec)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), delim, ec);
+}
+
+#if defined(ASIO_HAS_BOOST_REGEX)
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, const boost::regex& expr)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), expr);
+}
+
+template <typename SyncReadStream, typename Allocator>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, const boost::regex& expr,
+    asio::error_code& ec)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), expr, ec);
+}
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+
+template <typename SyncReadStream, typename Allocator, typename MatchCondition>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, MatchCondition match_condition,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type*)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), match_condition);
+}
+
+template <typename SyncReadStream, typename Allocator, typename MatchCondition>
+inline std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    MatchCondition match_condition, asio::error_code& ec,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type*)
+{
+  return read_until(s, basic_streambuf_ref<Allocator>(b), match_condition, ec);
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+namespace detail
+{
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  class read_until_delim_op
+  {
+  public:
+    template <typename BufferSequence>
+    read_until_delim_op(AsyncReadStream& stream,
+        ASIO_MOVE_ARG(BufferSequence) buffers,
+        char delim, ReadHandler& handler)
+      : stream_(stream),
+        buffers_(ASIO_MOVE_CAST(BufferSequence)(buffers)),
+        delim_(delim),
+        start_(0),
+        search_position_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_until_delim_op(const read_until_delim_op& other)
+      : stream_(other.stream_),
+        buffers_(other.buffers_),
+        delim_(other.delim_),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_until_delim_op(read_until_delim_op&& other)
+      : stream_(other.stream_),
+        buffers_(ASIO_MOVE_CAST(DynamicBuffer)(other.buffers_)),
+        delim_(other.delim_),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      const std::size_t not_found = (std::numeric_limits<std::size_t>::max)();
+      std::size_t bytes_to_read;
+      switch (start_ = start)
+      {
+      case 1:
+        for (;;)
+        {
+          {
+            // Determine the range of the data to be searched.
+            typedef typename DynamicBuffer::const_buffers_type
+              buffers_type;
+            typedef buffers_iterator<buffers_type> iterator;
+            buffers_type data_buffers = buffers_.data();
+            iterator begin = iterator::begin(data_buffers);
+            iterator start_pos = begin + search_position_;
+            iterator end = iterator::end(data_buffers);
+
+            // Look for a match.
+            iterator iter = std::find(start_pos, end, delim_);
+            if (iter != end)
+            {
+              // Found a match. We're done.
+              search_position_ = iter - begin + 1;
+              bytes_to_read = 0;
+            }
+
+            // No match yet. Check if buffer is full.
+            else if (buffers_.size() == buffers_.max_size())
+            {
+              search_position_ = not_found;
+              bytes_to_read = 0;
+            }
+
+            // Need to read some more data.
+            else
+            {
+              // Next search can start with the new data.
+              search_position_ = end - begin;
+              bytes_to_read = std::min<std::size_t>(
+                    std::max<std::size_t>(512,
+                      buffers_.capacity() - buffers_.size()),
+                    std::min<std::size_t>(65536,
+                      buffers_.max_size() - buffers_.size()));
+            }
+          }
+
+          // Check if we're done.
+          if (!start && bytes_to_read == 0)
+            break;
+
+          // Start a new asynchronous read operation to obtain more data.
+          stream_.async_read_some(buffers_.prepare(bytes_to_read),
+              ASIO_MOVE_CAST(read_until_delim_op)(*this));
+          return; default:
+          buffers_.commit(bytes_transferred);
+          if (ec || bytes_transferred == 0)
+            break;
+        }
+
+        const asio::error_code result_ec =
+          (search_position_ == not_found)
+          ? error::not_found : ec;
+
+        const std::size_t result_n =
+          (ec || search_position_ == not_found)
+          ? 0 : search_position_;
+
+        handler_(result_ec, result_n);
+      }
+    }
+
+  //private:
+    AsyncReadStream& stream_;
+    DynamicBuffer buffers_;
+    char delim_;
+    int start_;
+    std::size_t search_position_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_until_delim_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_until_delim_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_until_delim_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_until_delim_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_until_delim_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::read_until_delim_op<AsyncReadStream,
+      DynamicBuffer, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::read_until_delim_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::read_until_delim_op<AsyncReadStream,
+      DynamicBuffer, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::read_until_delim_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    char delim, ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::read_until_delim_op<AsyncReadStream,
+    typename decay<DynamicBuffer>::type,
+      ASIO_HANDLER_TYPE(ReadHandler,
+        void (asio::error_code, std::size_t))>(
+          s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+            delim, init.completion_handler)(asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+namespace detail
+{
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  class read_until_delim_string_op
+  {
+  public:
+    template <typename BufferSequence>
+    read_until_delim_string_op(AsyncReadStream& stream,
+        ASIO_MOVE_ARG(BufferSequence) buffers,
+        const std::string& delim, ReadHandler& handler)
+      : stream_(stream),
+        buffers_(ASIO_MOVE_CAST(BufferSequence)(buffers)),
+        delim_(delim),
+        start_(0),
+        search_position_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_until_delim_string_op(const read_until_delim_string_op& other)
+      : stream_(other.stream_),
+        buffers_(other.buffers_),
+        delim_(other.delim_),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_until_delim_string_op(read_until_delim_string_op&& other)
+      : stream_(other.stream_),
+        buffers_(ASIO_MOVE_CAST(DynamicBuffer)(other.buffers_)),
+        delim_(ASIO_MOVE_CAST(std::string)(other.delim_)),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      const std::size_t not_found = (std::numeric_limits<std::size_t>::max)();
+      std::size_t bytes_to_read;
+      switch (start_ = start)
+      {
+      case 1:
+        for (;;)
+        {
+          {
+            // Determine the range of the data to be searched.
+            typedef typename DynamicBuffer::const_buffers_type
+              buffers_type;
+            typedef buffers_iterator<buffers_type> iterator;
+            buffers_type data_buffers = buffers_.data();
+            iterator begin = iterator::begin(data_buffers);
+            iterator start_pos = begin + search_position_;
+            iterator end = iterator::end(data_buffers);
+
+            // Look for a match.
+            std::pair<iterator, bool> result = detail::partial_search(
+                start_pos, end, delim_.begin(), delim_.end());
+            if (result.first != end && result.second)
+            {
+              // Full match. We're done.
+              search_position_ = result.first - begin + delim_.length();
+              bytes_to_read = 0;
+            }
+
+            // No match yet. Check if buffer is full.
+            else if (buffers_.size() == buffers_.max_size())
+            {
+              search_position_ = not_found;
+              bytes_to_read = 0;
+            }
+
+            // Need to read some more data.
+            else
+            {
+              if (result.first != end)
+              {
+                // Partial match. Next search needs to start from beginning of
+                // match.
+                search_position_ = result.first - begin;
+              }
+              else
+              {
+                // Next search can start with the new data.
+                search_position_ = end - begin;
+              }
+
+              bytes_to_read = std::min<std::size_t>(
+                    std::max<std::size_t>(512,
+                      buffers_.capacity() - buffers_.size()),
+                    std::min<std::size_t>(65536,
+                      buffers_.max_size() - buffers_.size()));
+            }
+          }
+
+          // Check if we're done.
+          if (!start && bytes_to_read == 0)
+            break;
+
+          // Start a new asynchronous read operation to obtain more data.
+          stream_.async_read_some(buffers_.prepare(bytes_to_read),
+              ASIO_MOVE_CAST(read_until_delim_string_op)(*this));
+          return; default:
+          buffers_.commit(bytes_transferred);
+          if (ec || bytes_transferred == 0)
+            break;
+        }
+
+        const asio::error_code result_ec =
+          (search_position_ == not_found)
+          ? error::not_found : ec;
+
+        const std::size_t result_n =
+          (ec || search_position_ == not_found)
+          ? 0 : search_position_;
+
+        handler_(result_ec, result_n);
+      }
+    }
+
+  //private:
+    AsyncReadStream& stream_;
+    DynamicBuffer buffers_;
+    std::string delim_;
+    int start_;
+    std::size_t search_position_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_until_delim_string_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_until_delim_string_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_until_delim_string_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_until_delim_string_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_until_delim_string_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::read_until_delim_string_op<AsyncReadStream,
+      DynamicBuffer, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::read_until_delim_string_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::read_until_delim_string_op<AsyncReadStream,
+      DynamicBuffer, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::read_until_delim_string_op<AsyncReadStream,
+        DynamicBuffer, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_STRING_VIEW_PARAM delim,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::read_until_delim_string_op<AsyncReadStream,
+    typename decay<DynamicBuffer>::type,
+      ASIO_HANDLER_TYPE(ReadHandler,
+        void (asio::error_code, std::size_t))>(
+          s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+            static_cast<std::string>(delim),
+              init.completion_handler)(asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if defined(ASIO_HAS_BOOST_REGEX)
+
+namespace detail
+{
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename RegEx, typename ReadHandler>
+  class read_until_expr_op
+  {
+  public:
+    template <typename BufferSequence>
+    read_until_expr_op(AsyncReadStream& stream,
+        ASIO_MOVE_ARG(BufferSequence) buffers,
+        const boost::regex& expr, ReadHandler& handler)
+      : stream_(stream),
+        buffers_(ASIO_MOVE_CAST(BufferSequence)(buffers)),
+        expr_(expr),
+        start_(0),
+        search_position_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_until_expr_op(const read_until_expr_op& other)
+      : stream_(other.stream_),
+        buffers_(other.buffers_),
+        expr_(other.expr_),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_until_expr_op(read_until_expr_op&& other)
+      : stream_(other.stream_),
+        buffers_(ASIO_MOVE_CAST(DynamicBuffer)(other.buffers_)),
+        expr_(other.expr_),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      const std::size_t not_found = (std::numeric_limits<std::size_t>::max)();
+      std::size_t bytes_to_read;
+      switch (start_ = start)
+      {
+      case 1:
+        for (;;)
+        {
+          {
+            // Determine the range of the data to be searched.
+            typedef typename DynamicBuffer::const_buffers_type
+              buffers_type;
+            typedef buffers_iterator<buffers_type> iterator;
+            buffers_type data_buffers = buffers_.data();
+            iterator begin = iterator::begin(data_buffers);
+            iterator start_pos = begin + search_position_;
+            iterator end = iterator::end(data_buffers);
+
+            // Look for a match.
+            boost::match_results<iterator,
+              typename std::vector<boost::sub_match<iterator> >::allocator_type>
+                match_results;
+            bool match = regex_search(start_pos, end, match_results, expr_,
+                boost::match_default | boost::match_partial);
+            if (match && match_results[0].matched)
+            {
+              // Full match. We're done.
+              search_position_ = match_results[0].second - begin;
+              bytes_to_read = 0;
+            }
+
+            // No match yet. Check if buffer is full.
+            else if (buffers_.size() == buffers_.max_size())
+            {
+              search_position_ = not_found;
+              bytes_to_read = 0;
+            }
+
+            // Need to read some more data.
+            else
+            {
+              if (match)
+              {
+                // Partial match. Next search needs to start from beginning of
+                // match.
+                search_position_ = match_results[0].first - begin;
+              }
+              else
+              {
+                // Next search can start with the new data.
+                search_position_ = end - begin;
+              }
+
+              bytes_to_read = std::min<std::size_t>(
+                    std::max<std::size_t>(512,
+                      buffers_.capacity() - buffers_.size()),
+                    std::min<std::size_t>(65536,
+                      buffers_.max_size() - buffers_.size()));
+            }
+          }
+
+          // Check if we're done.
+          if (!start && bytes_to_read == 0)
+            break;
+
+          // Start a new asynchronous read operation to obtain more data.
+          stream_.async_read_some(buffers_.prepare(bytes_to_read),
+              ASIO_MOVE_CAST(read_until_expr_op)(*this));
+          return; default:
+          buffers_.commit(bytes_transferred);
+          if (ec || bytes_transferred == 0)
+            break;
+        }
+
+        const asio::error_code result_ec =
+          (search_position_ == not_found)
+          ? error::not_found : ec;
+
+        const std::size_t result_n =
+          (ec || search_position_ == not_found)
+          ? 0 : search_position_;
+
+        handler_(result_ec, result_n);
+      }
+    }
+
+  //private:
+    AsyncReadStream& stream_;
+    DynamicBuffer buffers_;
+    RegEx expr_;
+    int start_;
+    std::size_t search_position_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename RegEx, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_until_expr_op<AsyncReadStream,
+        DynamicBuffer, RegEx, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename RegEx, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_until_expr_op<AsyncReadStream,
+        DynamicBuffer, RegEx, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename RegEx, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_until_expr_op<AsyncReadStream,
+        DynamicBuffer, RegEx, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename RegEx, typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_until_expr_op<AsyncReadStream,
+        DynamicBuffer, RegEx, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename RegEx, typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_until_expr_op<AsyncReadStream,
+        DynamicBuffer, RegEx, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename RegEx, typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::read_until_expr_op<AsyncReadStream,
+      DynamicBuffer, RegEx, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::read_until_expr_op<AsyncReadStream,
+        DynamicBuffer, RegEx, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename RegEx, typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::read_until_expr_op<AsyncReadStream,
+      DynamicBuffer, RegEx, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::read_until_expr_op<AsyncReadStream,
+        DynamicBuffer, RegEx, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    const boost::regex& expr,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::read_until_expr_op<AsyncReadStream,
+    typename decay<DynamicBuffer>::type,
+      boost::regex, ASIO_HANDLER_TYPE(ReadHandler,
+        void (asio::error_code, std::size_t))>(
+          s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+            expr, init.completion_handler)(asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+
+namespace detail
+{
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename MatchCondition, typename ReadHandler>
+  class read_until_match_op
+  {
+  public:
+    template <typename BufferSequence>
+    read_until_match_op(AsyncReadStream& stream,
+        ASIO_MOVE_ARG(BufferSequence) buffers,
+        MatchCondition match_condition, ReadHandler& handler)
+      : stream_(stream),
+        buffers_(ASIO_MOVE_CAST(BufferSequence)(buffers)),
+        match_condition_(match_condition),
+        start_(0),
+        search_position_(0),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    read_until_match_op(const read_until_match_op& other)
+      : stream_(other.stream_),
+        buffers_(other.buffers_),
+        match_condition_(other.match_condition_),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(other.handler_)
+    {
+    }
+
+    read_until_match_op(read_until_match_op&& other)
+      : stream_(other.stream_),
+        buffers_(ASIO_MOVE_CAST(DynamicBuffer)(other.buffers_)),
+        match_condition_(other.match_condition_),
+        start_(other.start_),
+        search_position_(other.search_position_),
+        handler_(ASIO_MOVE_CAST(ReadHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      const std::size_t not_found = (std::numeric_limits<std::size_t>::max)();
+      std::size_t bytes_to_read;
+      switch (start_ = start)
+      {
+      case 1:
+        for (;;)
+        {
+          {
+            // Determine the range of the data to be searched.
+            typedef typename DynamicBuffer::const_buffers_type
+              buffers_type;
+            typedef buffers_iterator<buffers_type> iterator;
+            buffers_type data_buffers = buffers_.data();
+            iterator begin = iterator::begin(data_buffers);
+            iterator start_pos = begin + search_position_;
+            iterator end = iterator::end(data_buffers);
+
+            // Look for a match.
+            std::pair<iterator, bool> result = match_condition_(start_pos, end);
+            if (result.second)
+            {
+              // Full match. We're done.
+              search_position_ = result.first - begin;
+              bytes_to_read = 0;
+            }
+
+            // No match yet. Check if buffer is full.
+            else if (buffers_.size() == buffers_.max_size())
+            {
+              search_position_ = not_found;
+              bytes_to_read = 0;
+            }
+
+            // Need to read some more data.
+            else
+            {
+              if (result.first != end)
+              {
+                // Partial match. Next search needs to start from beginning of
+                // match.
+                search_position_ = result.first - begin;
+              }
+              else
+              {
+                // Next search can start with the new data.
+                search_position_ = end - begin;
+              }
+
+              bytes_to_read = std::min<std::size_t>(
+                    std::max<std::size_t>(512,
+                      buffers_.capacity() - buffers_.size()),
+                    std::min<std::size_t>(65536,
+                      buffers_.max_size() - buffers_.size()));
+            }
+          }
+
+          // Check if we're done.
+          if (!start && bytes_to_read == 0)
+            break;
+
+          // Start a new asynchronous read operation to obtain more data.
+          stream_.async_read_some(buffers_.prepare(bytes_to_read),
+              ASIO_MOVE_CAST(read_until_match_op)(*this));
+          return; default:
+          buffers_.commit(bytes_transferred);
+          if (ec || bytes_transferred == 0)
+            break;
+        }
+
+        const asio::error_code result_ec =
+          (search_position_ == not_found)
+          ? error::not_found : ec;
+
+        const std::size_t result_n =
+          (ec || search_position_ == not_found)
+          ? 0 : search_position_;
+
+        handler_(result_ec, result_n);
+      }
+    }
+
+  //private:
+    AsyncReadStream& stream_;
+    DynamicBuffer buffers_;
+    MatchCondition match_condition_;
+    int start_;
+    std::size_t search_position_;
+    ReadHandler handler_;
+  };
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename MatchCondition, typename ReadHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      read_until_match_op<AsyncReadStream, DynamicBuffer,
+        MatchCondition, ReadHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename MatchCondition, typename ReadHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      read_until_match_op<AsyncReadStream, DynamicBuffer,
+        MatchCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncReadStream, typename DynamicBuffer,
+      typename MatchCondition, typename ReadHandler>
+  inline bool asio_handler_is_continuation(
+      read_until_match_op<AsyncReadStream, DynamicBuffer,
+        MatchCondition, ReadHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename MatchCondition,
+      typename ReadHandler>
+  inline void asio_handler_invoke(Function& function,
+      read_until_match_op<AsyncReadStream, DynamicBuffer,
+        MatchCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncReadStream,
+      typename DynamicBuffer, typename MatchCondition,
+      typename ReadHandler>
+  inline void asio_handler_invoke(const Function& function,
+      read_until_match_op<AsyncReadStream, DynamicBuffer,
+      MatchCondition, ReadHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename MatchCondition, typename ReadHandler, typename Allocator>
+struct associated_allocator<
+    detail::read_until_match_op<AsyncReadStream,
+      DynamicBuffer, MatchCondition, ReadHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<ReadHandler, Allocator>::type type;
+
+  static type get(
+      const detail::read_until_match_op<AsyncReadStream,
+        DynamicBuffer, MatchCondition, ReadHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<ReadHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename MatchCondition, typename ReadHandler, typename Executor>
+struct associated_executor<
+    detail::read_until_match_op<AsyncReadStream,
+      DynamicBuffer, MatchCondition, ReadHandler>,
+    Executor>
+{
+  typedef typename associated_executor<ReadHandler, Executor>::type type;
+
+  static type get(
+      const detail::read_until_match_op<AsyncReadStream,
+        DynamicBuffer, MatchCondition, ReadHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<ReadHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename MatchCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    MatchCondition match_condition, ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a ReadHandler.
+  ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+  async_completion<ReadHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::read_until_match_op<AsyncReadStream,
+    typename decay<DynamicBuffer>::type,
+      MatchCondition, ASIO_HANDLER_TYPE(ReadHandler,
+        void (asio::error_code, std::size_t))>(
+          s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+            match_condition, init.completion_handler)(
+              asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    char delim, ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  return async_read_until(s, basic_streambuf_ref<Allocator>(b),
+      delim, ASIO_MOVE_CAST(ReadHandler)(handler));
+}
+
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    ASIO_STRING_VIEW_PARAM delim,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  return async_read_until(s, basic_streambuf_ref<Allocator>(b),
+      delim, ASIO_MOVE_CAST(ReadHandler)(handler));
+}
+
+#if defined(ASIO_HAS_BOOST_REGEX)
+
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, const boost::regex& expr,
+    ASIO_MOVE_ARG(ReadHandler) handler)
+{
+  return async_read_until(s, basic_streambuf_ref<Allocator>(b),
+      expr, ASIO_MOVE_CAST(ReadHandler)(handler));
+}
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+
+template <typename AsyncReadStream, typename Allocator,
+    typename MatchCondition, typename ReadHandler>
+inline ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    MatchCondition match_condition, ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type*)
+{
+  return async_read_until(s, basic_streambuf_ref<Allocator>(b),
+      match_condition, ASIO_MOVE_CAST(ReadHandler)(handler));
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_READ_UNTIL_HPP
diff --git a/subprojects/asio/include/asio/impl/serial_port_base.hpp b/subprojects/asio/include/asio/impl/serial_port_base.hpp
new file mode 100644
index 000000000..cdc201d8a
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/serial_port_base.hpp
@@ -0,0 +1,59 @@
+//
+// impl/serial_port_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SERIAL_PORT_BASE_HPP
+#define ASIO_IMPL_SERIAL_PORT_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+inline serial_port_base::baud_rate::baud_rate(unsigned int rate)
+  : value_(rate)
+{
+}
+
+inline unsigned int serial_port_base::baud_rate::value() const
+{
+  return value_;
+}
+
+inline serial_port_base::flow_control::type
+serial_port_base::flow_control::value() const
+{
+  return value_;
+}
+
+inline serial_port_base::parity::type serial_port_base::parity::value() const
+{
+  return value_;
+}
+
+inline serial_port_base::stop_bits::type
+serial_port_base::stop_bits::value() const
+{
+  return value_;
+}
+
+inline unsigned int serial_port_base::character_size::value() const
+{
+  return value_;
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_SERIAL_PORT_BASE_HPP
diff --git a/subprojects/asio/include/asio/impl/serial_port_base.ipp b/subprojects/asio/include/asio/impl/serial_port_base.ipp
new file mode 100644
index 000000000..5d52ed59c
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/serial_port_base.ipp
@@ -0,0 +1,554 @@
+//
+// impl/serial_port_base.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SERIAL_PORT_BASE_IPP
+#define ASIO_IMPL_SERIAL_PORT_BASE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_SERIAL_PORT)
+
+#include <stdexcept>
+#include "asio/error.hpp"
+#include "asio/serial_port_base.hpp"
+#include "asio/detail/throw_exception.hpp"
+
+#if defined(GENERATING_DOCUMENTATION)
+# define ASIO_OPTION_STORAGE implementation_defined
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# define ASIO_OPTION_STORAGE DCB
+#else
+# define ASIO_OPTION_STORAGE termios
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+ASIO_SYNC_OP_VOID serial_port_base::baud_rate::store(
+    ASIO_OPTION_STORAGE& storage, asio::error_code& ec) const
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  storage.BaudRate = value_;
+#else
+  speed_t baud;
+  switch (value_)
+  {
+  // Do POSIX-specified rates first.
+  case 0: baud = B0; break;
+  case 50: baud = B50; break;
+  case 75: baud = B75; break;
+  case 110: baud = B110; break;
+  case 134: baud = B134; break;
+  case 150: baud = B150; break;
+  case 200: baud = B200; break;
+  case 300: baud = B300; break;
+  case 600: baud = B600; break;
+  case 1200: baud = B1200; break;
+  case 1800: baud = B1800; break;
+  case 2400: baud = B2400; break;
+  case 4800: baud = B4800; break;
+  case 9600: baud = B9600; break;
+  case 19200: baud = B19200; break;
+  case 38400: baud = B38400; break;
+  // And now the extended ones conditionally.
+# ifdef B7200
+  case 7200: baud = B7200; break;
+# endif
+# ifdef B14400
+  case 14400: baud = B14400; break;
+# endif
+# ifdef B57600
+  case 57600: baud = B57600; break;
+# endif
+# ifdef B115200
+  case 115200: baud = B115200; break;
+# endif
+# ifdef B230400
+  case 230400: baud = B230400; break;
+# endif
+# ifdef B460800
+  case 460800: baud = B460800; break;
+# endif
+# ifdef B500000
+  case 500000: baud = B500000; break;
+# endif
+# ifdef B576000
+  case 576000: baud = B576000; break;
+# endif
+# ifdef B921600
+  case 921600: baud = B921600; break;
+# endif
+# ifdef B1000000
+  case 1000000: baud = B1000000; break;
+# endif
+# ifdef B1152000
+  case 1152000: baud = B1152000; break;
+# endif
+# ifdef B2000000
+  case 2000000: baud = B2000000; break;
+# endif
+# ifdef B3000000
+  case 3000000: baud = B3000000; break;
+# endif
+# ifdef B3500000
+  case 3500000: baud = B3500000; break;
+# endif
+# ifdef B4000000
+  case 4000000: baud = B4000000; break;
+# endif
+  default:
+    ec = asio::error::invalid_argument;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+# if defined(_BSD_SOURCE) || defined(_DEFAULT_SOURCE)
+  ::cfsetspeed(&storage, baud);
+# else
+  ::cfsetispeed(&storage, baud);
+  ::cfsetospeed(&storage, baud);
+# endif
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::baud_rate::load(
+    const ASIO_OPTION_STORAGE& storage, asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  value_ = storage.BaudRate;
+#else
+  speed_t baud = ::cfgetospeed(&storage);
+  switch (baud)
+  {
+  // First do those specified by POSIX.
+  case B0: value_ = 0; break;
+  case B50: value_ = 50; break;
+  case B75: value_ = 75; break;
+  case B110: value_ = 110; break;
+  case B134: value_ = 134; break;
+  case B150: value_ = 150; break;
+  case B200: value_ = 200; break;
+  case B300: value_ = 300; break;
+  case B600: value_ = 600; break;
+  case B1200: value_ = 1200; break;
+  case B1800: value_ = 1800; break;
+  case B2400: value_ = 2400; break;
+  case B4800: value_ = 4800; break;
+  case B9600: value_ = 9600; break;
+  case B19200: value_ = 19200; break;
+  case B38400: value_ = 38400; break;
+  // Now conditionally handle a bunch of extended rates.
+# ifdef B7200
+  case B7200: value_ = 7200; break;
+# endif
+# ifdef B14400
+  case B14400: value_ = 14400; break;
+# endif
+# ifdef B57600
+  case B57600: value_ = 57600; break;
+# endif
+# ifdef B115200
+  case B115200: value_ = 115200; break;
+# endif
+# ifdef B230400
+  case B230400: value_ = 230400; break;
+# endif
+# ifdef B460800
+  case B460800: value_ = 460800; break;
+# endif
+# ifdef B500000
+  case B500000: value_ = 500000; break;
+# endif
+# ifdef B576000
+  case B576000: value_ = 576000; break;
+# endif
+# ifdef B921600
+  case B921600: value_ = 921600; break;
+# endif
+# ifdef B1000000
+  case B1000000: value_ = 1000000; break;
+# endif
+# ifdef B1152000
+  case B1152000: value_ = 1152000; break;
+# endif
+# ifdef B2000000
+  case B2000000: value_ = 2000000; break;
+# endif
+# ifdef B3000000
+  case B3000000: value_ = 3000000; break;
+# endif
+# ifdef B3500000
+  case B3500000: value_ = 3500000; break;
+# endif
+# ifdef B4000000
+  case B4000000: value_ = 4000000; break;
+# endif
+  default:
+    value_ = 0;
+    ec = asio::error::invalid_argument;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+serial_port_base::flow_control::flow_control(
+    serial_port_base::flow_control::type t)
+  : value_(t)
+{
+  if (t != none && t != software && t != hardware)
+  {
+    std::out_of_range ex("invalid flow_control value");
+    asio::detail::throw_exception(ex);
+  }
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::flow_control::store(
+    ASIO_OPTION_STORAGE& storage, asio::error_code& ec) const
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  storage.fOutxCtsFlow = FALSE;
+  storage.fOutxDsrFlow = FALSE;
+  storage.fTXContinueOnXoff = TRUE;
+  storage.fDtrControl = DTR_CONTROL_ENABLE;
+  storage.fDsrSensitivity = FALSE;
+  storage.fOutX = FALSE;
+  storage.fInX = FALSE;
+  storage.fRtsControl = RTS_CONTROL_ENABLE;
+  switch (value_)
+  {
+  case none:
+    break;
+  case software:
+    storage.fOutX = TRUE;
+    storage.fInX = TRUE;
+    break;
+  case hardware:
+    storage.fOutxCtsFlow = TRUE;
+    storage.fRtsControl = RTS_CONTROL_HANDSHAKE;
+    break;
+  default:
+    break;
+  }
+#else
+  switch (value_)
+  {
+  case none:
+    storage.c_iflag &= ~(IXOFF | IXON);
+# if defined(_BSD_SOURCE) || defined(_DEFAULT_SOURCE)
+    storage.c_cflag &= ~CRTSCTS;
+# elif defined(__QNXNTO__)
+    storage.c_cflag &= ~(IHFLOW | OHFLOW);
+# endif
+    break;
+  case software:
+    storage.c_iflag |= IXOFF | IXON;
+# if defined(_BSD_SOURCE) || defined(_DEFAULT_SOURCE)
+    storage.c_cflag &= ~CRTSCTS;
+# elif defined(__QNXNTO__)
+    storage.c_cflag &= ~(IHFLOW | OHFLOW);
+# endif
+    break;
+  case hardware:
+# if defined(_BSD_SOURCE) || defined(_DEFAULT_SOURCE)
+    storage.c_iflag &= ~(IXOFF | IXON);
+    storage.c_cflag |= CRTSCTS;
+    break;
+# elif defined(__QNXNTO__)
+    storage.c_iflag &= ~(IXOFF | IXON);
+    storage.c_cflag |= (IHFLOW | OHFLOW);
+    break;
+# else
+    ec = asio::error::operation_not_supported;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+# endif
+  default:
+    break;
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::flow_control::load(
+    const ASIO_OPTION_STORAGE& storage, asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  if (storage.fOutX && storage.fInX)
+  {
+    value_ = software;
+  }
+  else if (storage.fOutxCtsFlow && storage.fRtsControl == RTS_CONTROL_HANDSHAKE)
+  {
+    value_ = hardware;
+  }
+  else
+  {
+    value_ = none;
+  }
+#else
+  if (storage.c_iflag & (IXOFF | IXON))
+  {
+    value_ = software;
+  }
+# if defined(_BSD_SOURCE) || defined(_DEFAULT_SOURCE)
+  else if (storage.c_cflag & CRTSCTS)
+  {
+    value_ = hardware;
+  }
+# elif defined(__QNXNTO__)
+  else if (storage.c_cflag & IHFLOW && storage.c_cflag & OHFLOW)
+  {
+    value_ = hardware;
+  }
+# endif
+  else
+  {
+    value_ = none;
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+serial_port_base::parity::parity(serial_port_base::parity::type t)
+  : value_(t)
+{
+  if (t != none && t != odd && t != even)
+  {
+    std::out_of_range ex("invalid parity value");
+    asio::detail::throw_exception(ex);
+  }
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::parity::store(
+    ASIO_OPTION_STORAGE& storage, asio::error_code& ec) const
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  switch (value_)
+  {
+  case none:
+    storage.fParity = FALSE;
+    storage.Parity = NOPARITY;
+    break;
+  case odd:
+    storage.fParity = TRUE;
+    storage.Parity = ODDPARITY;
+    break;
+  case even:
+    storage.fParity = TRUE;
+    storage.Parity = EVENPARITY;
+    break;
+  default:
+    break;
+  }
+#else
+  switch (value_)
+  {
+  case none:
+    storage.c_iflag |= IGNPAR;
+    storage.c_cflag &= ~(PARENB | PARODD);
+    break;
+  case even:
+    storage.c_iflag &= ~(IGNPAR | PARMRK);
+    storage.c_iflag |= INPCK;
+    storage.c_cflag |= PARENB;
+    storage.c_cflag &= ~PARODD;
+    break;
+  case odd:
+    storage.c_iflag &= ~(IGNPAR | PARMRK);
+    storage.c_iflag |= INPCK;
+    storage.c_cflag |= (PARENB | PARODD);
+    break;
+  default:
+    break;
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::parity::load(
+    const ASIO_OPTION_STORAGE& storage, asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  if (storage.Parity == EVENPARITY)
+  {
+    value_ = even;
+  }
+  else if (storage.Parity == ODDPARITY)
+  {
+    value_ = odd;
+  }
+  else
+  {
+    value_ = none;
+  }
+#else
+  if (storage.c_cflag & PARENB)
+  {
+    if (storage.c_cflag & PARODD)
+    {
+      value_ = odd;
+    }
+    else
+    {
+      value_ = even;
+    }
+  }
+  else
+  {
+    value_ = none;
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+serial_port_base::stop_bits::stop_bits(
+    serial_port_base::stop_bits::type t)
+  : value_(t)
+{
+  if (t != one && t != onepointfive && t != two)
+  {
+    std::out_of_range ex("invalid stop_bits value");
+    asio::detail::throw_exception(ex);
+  }
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::stop_bits::store(
+    ASIO_OPTION_STORAGE& storage, asio::error_code& ec) const
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  switch (value_)
+  {
+  case one:
+    storage.StopBits = ONESTOPBIT;
+    break;
+  case onepointfive:
+    storage.StopBits = ONE5STOPBITS;
+    break;
+  case two:
+    storage.StopBits = TWOSTOPBITS;
+    break;
+  default:
+    break;
+  }
+#else
+  switch (value_)
+  {
+  case one:
+    storage.c_cflag &= ~CSTOPB;
+    break;
+  case two:
+    storage.c_cflag |= CSTOPB;
+    break;
+  default:
+    ec = asio::error::operation_not_supported;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::stop_bits::load(
+    const ASIO_OPTION_STORAGE& storage, asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  if (storage.StopBits == ONESTOPBIT)
+  {
+    value_ = one;
+  }
+  else if (storage.StopBits == ONE5STOPBITS)
+  {
+    value_ = onepointfive;
+  }
+  else if (storage.StopBits == TWOSTOPBITS)
+  {
+    value_ = two;
+  }
+  else
+  {
+    value_ = one;
+  }
+#else
+  value_ = (storage.c_cflag & CSTOPB) ? two : one;
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+serial_port_base::character_size::character_size(unsigned int t)
+  : value_(t)
+{
+  if (t < 5 || t > 8)
+  {
+    std::out_of_range ex("invalid character_size value");
+    asio::detail::throw_exception(ex);
+  }
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::character_size::store(
+    ASIO_OPTION_STORAGE& storage, asio::error_code& ec) const
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  storage.ByteSize = value_;
+#else
+  storage.c_cflag &= ~CSIZE;
+  switch (value_)
+  {
+  case 5: storage.c_cflag |= CS5; break;
+  case 6: storage.c_cflag |= CS6; break;
+  case 7: storage.c_cflag |= CS7; break;
+  case 8: storage.c_cflag |= CS8; break;
+  default: break;
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID serial_port_base::character_size::load(
+    const ASIO_OPTION_STORAGE& storage, asio::error_code& ec)
+{
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  value_ = storage.ByteSize;
+#else
+  if ((storage.c_cflag & CSIZE) == CS5) { value_ = 5; }
+  else if ((storage.c_cflag & CSIZE) == CS6) { value_ = 6; }
+  else if ((storage.c_cflag & CSIZE) == CS7) { value_ = 7; }
+  else if ((storage.c_cflag & CSIZE) == CS8) { value_ = 8; }
+  else
+  {
+    // Hmmm, use 8 for now.
+    value_ = 8;
+  }
+#endif
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#undef ASIO_OPTION_STORAGE
+
+#endif // defined(ASIO_HAS_SERIAL_PORT)
+
+#endif // ASIO_IMPL_SERIAL_PORT_BASE_IPP
diff --git a/subprojects/asio/include/asio/impl/spawn.hpp b/subprojects/asio/include/asio/impl/spawn.hpp
new file mode 100644
index 000000000..5594ad93d
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/spawn.hpp
@@ -0,0 +1,535 @@
+//
+// impl/spawn.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SPAWN_HPP
+#define ASIO_IMPL_SPAWN_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/async_result.hpp"
+#include "asio/bind_executor.hpp"
+#include "asio/detail/atomic_count.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/system_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+  template <typename Handler, typename T>
+  class coro_handler
+  {
+  public:
+    coro_handler(basic_yield_context<Handler> ctx)
+      : coro_(ctx.coro_.lock()),
+        ca_(ctx.ca_),
+        handler_(ctx.handler_),
+        ready_(0),
+        ec_(ctx.ec_),
+        value_(0)
+    {
+    }
+
+    void operator()(T value)
+    {
+      *ec_ = asio::error_code();
+      *value_ = ASIO_MOVE_CAST(T)(value);
+      if (--*ready_ == 0)
+        (*coro_)();
+    }
+
+    void operator()(asio::error_code ec, T value)
+    {
+      *ec_ = ec;
+      *value_ = ASIO_MOVE_CAST(T)(value);
+      if (--*ready_ == 0)
+        (*coro_)();
+    }
+
+  //private:
+    shared_ptr<typename basic_yield_context<Handler>::callee_type> coro_;
+    typename basic_yield_context<Handler>::caller_type& ca_;
+    Handler handler_;
+    atomic_count* ready_;
+    asio::error_code* ec_;
+    T* value_;
+  };
+
+  template <typename Handler>
+  class coro_handler<Handler, void>
+  {
+  public:
+    coro_handler(basic_yield_context<Handler> ctx)
+      : coro_(ctx.coro_.lock()),
+        ca_(ctx.ca_),
+        handler_(ctx.handler_),
+        ready_(0),
+        ec_(ctx.ec_)
+    {
+    }
+
+    void operator()()
+    {
+      *ec_ = asio::error_code();
+      if (--*ready_ == 0)
+        (*coro_)();
+    }
+
+    void operator()(asio::error_code ec)
+    {
+      *ec_ = ec;
+      if (--*ready_ == 0)
+        (*coro_)();
+    }
+
+  //private:
+    shared_ptr<typename basic_yield_context<Handler>::callee_type> coro_;
+    typename basic_yield_context<Handler>::caller_type& ca_;
+    Handler handler_;
+    atomic_count* ready_;
+    asio::error_code* ec_;
+  };
+
+  template <typename Handler, typename T>
+  inline void* asio_handler_allocate(std::size_t size,
+      coro_handler<Handler, T>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename Handler, typename T>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      coro_handler<Handler, T>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename Handler, typename T>
+  inline bool asio_handler_is_continuation(coro_handler<Handler, T>*)
+  {
+    return true;
+  }
+
+  template <typename Function, typename Handler, typename T>
+  inline void asio_handler_invoke(Function& function,
+      coro_handler<Handler, T>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename Handler, typename T>
+  inline void asio_handler_invoke(const Function& function,
+      coro_handler<Handler, T>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Handler, typename T>
+  class coro_async_result
+  {
+  public:
+    typedef coro_handler<Handler, T> completion_handler_type;
+    typedef T return_type;
+
+    explicit coro_async_result(completion_handler_type& h)
+      : handler_(h),
+        ca_(h.ca_),
+        ready_(2)
+    {
+      h.ready_ = &ready_;
+      out_ec_ = h.ec_;
+      if (!out_ec_) h.ec_ = &ec_;
+      h.value_ = &value_;
+    }
+
+    return_type get()
+    {
+      // Must not hold shared_ptr to coro while suspended.
+      handler_.coro_.reset();
+
+      if (--ready_ != 0)
+        ca_();
+      if (!out_ec_ && ec_) throw asio::system_error(ec_);
+      return ASIO_MOVE_CAST(return_type)(value_);
+    }
+
+  private:
+    completion_handler_type& handler_;
+    typename basic_yield_context<Handler>::caller_type& ca_;
+    atomic_count ready_;
+    asio::error_code* out_ec_;
+    asio::error_code ec_;
+    return_type value_;
+  };
+
+  template <typename Handler>
+  class coro_async_result<Handler, void>
+  {
+  public:
+    typedef coro_handler<Handler, void> completion_handler_type;
+    typedef void return_type;
+
+    explicit coro_async_result(completion_handler_type& h)
+      : handler_(h),
+        ca_(h.ca_),
+        ready_(2)
+    {
+      h.ready_ = &ready_;
+      out_ec_ = h.ec_;
+      if (!out_ec_) h.ec_ = &ec_;
+    }
+
+    void get()
+    {
+      // Must not hold shared_ptr to coro while suspended.
+      handler_.coro_.reset();
+
+      if (--ready_ != 0)
+        ca_();
+      if (!out_ec_ && ec_) throw asio::system_error(ec_);
+    }
+
+  private:
+    completion_handler_type& handler_;
+    typename basic_yield_context<Handler>::caller_type& ca_;
+    atomic_count ready_;
+    asio::error_code* out_ec_;
+    asio::error_code ec_;
+  };
+
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename Handler, typename ReturnType>
+class async_result<basic_yield_context<Handler>, ReturnType()>
+  : public detail::coro_async_result<Handler, void>
+{
+public:
+  explicit async_result(
+    typename detail::coro_async_result<Handler,
+      void>::completion_handler_type& h)
+    : detail::coro_async_result<Handler, void>(h)
+  {
+  }
+};
+
+template <typename Handler, typename ReturnType, typename Arg1>
+class async_result<basic_yield_context<Handler>, ReturnType(Arg1)>
+  : public detail::coro_async_result<Handler, typename decay<Arg1>::type>
+{
+public:
+  explicit async_result(
+    typename detail::coro_async_result<Handler,
+      typename decay<Arg1>::type>::completion_handler_type& h)
+    : detail::coro_async_result<Handler, typename decay<Arg1>::type>(h)
+  {
+  }
+};
+
+template <typename Handler, typename ReturnType>
+class async_result<basic_yield_context<Handler>,
+    ReturnType(asio::error_code)>
+  : public detail::coro_async_result<Handler, void>
+{
+public:
+  explicit async_result(
+    typename detail::coro_async_result<Handler,
+      void>::completion_handler_type& h)
+    : detail::coro_async_result<Handler, void>(h)
+  {
+  }
+};
+
+template <typename Handler, typename ReturnType, typename Arg2>
+class async_result<basic_yield_context<Handler>,
+    ReturnType(asio::error_code, Arg2)>
+  : public detail::coro_async_result<Handler, typename decay<Arg2>::type>
+{
+public:
+  explicit async_result(
+    typename detail::coro_async_result<Handler,
+      typename decay<Arg2>::type>::completion_handler_type& h)
+    : detail::coro_async_result<Handler, typename decay<Arg2>::type>(h)
+  {
+  }
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+template <typename Handler, typename ReturnType>
+struct handler_type<basic_yield_context<Handler>, ReturnType()>
+{
+  typedef detail::coro_handler<Handler, void> type;
+};
+
+template <typename Handler, typename ReturnType, typename Arg1>
+struct handler_type<basic_yield_context<Handler>, ReturnType(Arg1)>
+{
+  typedef detail::coro_handler<Handler, typename decay<Arg1>::type> type;
+};
+
+template <typename Handler, typename ReturnType>
+struct handler_type<basic_yield_context<Handler>,
+    ReturnType(asio::error_code)>
+{
+  typedef detail::coro_handler<Handler, void> type;
+};
+
+template <typename Handler, typename ReturnType, typename Arg2>
+struct handler_type<basic_yield_context<Handler>,
+    ReturnType(asio::error_code, Arg2)>
+{
+  typedef detail::coro_handler<Handler, typename decay<Arg2>::type> type;
+};
+
+template <typename Handler, typename T>
+class async_result<detail::coro_handler<Handler, T> >
+  : public detail::coro_async_result<Handler, T>
+{
+public:
+  typedef typename detail::coro_async_result<Handler, T>::return_type type;
+
+  explicit async_result(
+    typename detail::coro_async_result<Handler,
+      T>::completion_handler_type& h)
+    : detail::coro_async_result<Handler, T>(h)
+  {
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Handler, typename T, typename Allocator>
+struct associated_allocator<detail::coro_handler<Handler, T>, Allocator>
+{
+  typedef typename associated_allocator<Handler, Allocator>::type type;
+
+  static type get(const detail::coro_handler<Handler, T>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<Handler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Handler, typename T, typename Executor>
+struct associated_executor<detail::coro_handler<Handler, T>, Executor>
+{
+  typedef typename associated_executor<Handler, Executor>::type type;
+
+  static type get(const detail::coro_handler<Handler, T>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<Handler, Executor>::get(h.handler_, ex);
+  }
+};
+
+namespace detail {
+
+  template <typename Handler, typename Function>
+  struct spawn_data : private noncopyable
+  {
+    template <typename Hand, typename Func>
+    spawn_data(ASIO_MOVE_ARG(Hand) handler,
+        bool call_handler, ASIO_MOVE_ARG(Func) function)
+      : handler_(ASIO_MOVE_CAST(Hand)(handler)),
+        call_handler_(call_handler),
+        function_(ASIO_MOVE_CAST(Func)(function))
+    {
+    }
+
+    weak_ptr<typename basic_yield_context<Handler>::callee_type> coro_;
+    Handler handler_;
+    bool call_handler_;
+    Function function_;
+  };
+
+  template <typename Handler, typename Function>
+  struct coro_entry_point
+  {
+    void operator()(typename basic_yield_context<Handler>::caller_type& ca)
+    {
+      shared_ptr<spawn_data<Handler, Function> > data(data_);
+#if !defined(BOOST_COROUTINES_UNIDIRECT) && !defined(BOOST_COROUTINES_V2)
+      ca(); // Yield until coroutine pointer has been initialised.
+#endif // !defined(BOOST_COROUTINES_UNIDIRECT) && !defined(BOOST_COROUTINES_V2)
+      const basic_yield_context<Handler> yield(
+          data->coro_, ca, data->handler_);
+
+      (data->function_)(yield);
+      if (data->call_handler_)
+        (data->handler_)();
+    }
+
+    shared_ptr<spawn_data<Handler, Function> > data_;
+  };
+
+  template <typename Handler, typename Function>
+  struct spawn_helper
+  {
+    void operator()()
+    {
+      typedef typename basic_yield_context<Handler>::callee_type callee_type;
+      coro_entry_point<Handler, Function> entry_point = { data_ };
+      shared_ptr<callee_type> coro(new callee_type(entry_point, attributes_));
+      data_->coro_ = coro;
+      (*coro)();
+    }
+
+    shared_ptr<spawn_data<Handler, Function> > data_;
+    boost::coroutines::attributes attributes_;
+  };
+
+  template <typename Function, typename Handler, typename Function1>
+  inline void asio_handler_invoke(Function& function,
+      spawn_helper<Handler, Function1>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->data_->handler_);
+  }
+
+  template <typename Function, typename Handler, typename Function1>
+  inline void asio_handler_invoke(const Function& function,
+      spawn_helper<Handler, Function1>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->data_->handler_);
+  }
+
+  inline void default_spawn_handler() {}
+
+} // namespace detail
+
+template <typename Function>
+inline void spawn(ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes)
+{
+  typedef typename decay<Function>::type function_type;
+
+  typename associated_executor<function_type>::type ex(
+      (get_associated_executor)(function));
+
+  asio::spawn(ex, ASIO_MOVE_CAST(Function)(function), attributes);
+}
+
+template <typename Handler, typename Function>
+void spawn(ASIO_MOVE_ARG(Handler) handler,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes,
+    typename enable_if<!is_executor<typename decay<Handler>::type>::value &&
+      !is_convertible<Handler&, execution_context&>::value>::type*)
+{
+  typedef typename decay<Handler>::type handler_type;
+  typedef typename decay<Function>::type function_type;
+
+  typename associated_executor<handler_type>::type ex(
+      (get_associated_executor)(handler));
+
+  typename associated_allocator<handler_type>::type a(
+      (get_associated_allocator)(handler));
+
+  detail::spawn_helper<handler_type, function_type> helper;
+  helper.data_.reset(
+      new detail::spawn_data<handler_type, function_type>(
+        ASIO_MOVE_CAST(Handler)(handler), true,
+        ASIO_MOVE_CAST(Function)(function)));
+  helper.attributes_ = attributes;
+
+  ex.dispatch(helper, a);
+}
+
+template <typename Handler, typename Function>
+void spawn(basic_yield_context<Handler> ctx,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes)
+{
+  typedef typename decay<Function>::type function_type;
+
+  Handler handler(ctx.handler_); // Explicit copy that might be moved from.
+
+  typename associated_executor<Handler>::type ex(
+      (get_associated_executor)(handler));
+
+  typename associated_allocator<Handler>::type a(
+      (get_associated_allocator)(handler));
+
+  detail::spawn_helper<Handler, function_type> helper;
+  helper.data_.reset(
+      new detail::spawn_data<Handler, function_type>(
+        ASIO_MOVE_CAST(Handler)(handler), false,
+        ASIO_MOVE_CAST(Function)(function)));
+  helper.attributes_ = attributes;
+
+  ex.dispatch(helper, a);
+}
+
+template <typename Function, typename Executor>
+inline void spawn(const Executor& ex,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes,
+    typename enable_if<is_executor<Executor>::value>::type*)
+{
+  asio::spawn(asio::strand<Executor>(ex),
+      ASIO_MOVE_CAST(Function)(function), attributes);
+}
+
+template <typename Function, typename Executor>
+inline void spawn(const strand<Executor>& ex,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes)
+{
+  asio::spawn(asio::bind_executor(
+        ex, &detail::default_spawn_handler),
+      ASIO_MOVE_CAST(Function)(function), attributes);
+}
+
+template <typename Function>
+inline void spawn(const asio::io_context::strand& s,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes)
+{
+  asio::spawn(asio::bind_executor(
+        s, &detail::default_spawn_handler),
+      ASIO_MOVE_CAST(Function)(function), attributes);
+}
+
+template <typename Function, typename ExecutionContext>
+inline void spawn(ExecutionContext& ctx,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type*)
+{
+  asio::spawn(ctx.get_executor(),
+      ASIO_MOVE_CAST(Function)(function), attributes);
+}
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_SPAWN_HPP
diff --git a/subprojects/asio/include/asio/impl/src.cpp b/subprojects/asio/include/asio/impl/src.cpp
new file mode 100644
index 000000000..e8a5953db
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/src.cpp
@@ -0,0 +1,25 @@
+//
+// impl/src.cpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#if defined(_MSC_VER) \
+  || defined(__BORLANDC__) \
+  || defined(__DMC__)
+# pragma message ( \
+    "This file is deprecated. " \
+    "Please #include <asio/impl/src.hpp> instead.")
+#elif defined(__GNUC__) \
+  || defined(__HP_aCC) \
+  || defined(__SUNPRO_CC) \
+  || defined(__IBMCPP__)
+# warning "This file is deprecated."
+# warning "Please #include <asio/impl/src.hpp> instead."
+#endif
+
+#include "asio/impl/src.hpp"
diff --git a/subprojects/asio/include/asio/impl/src.hpp b/subprojects/asio/include/asio/impl/src.hpp
new file mode 100644
index 000000000..a72637b94
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/src.hpp
@@ -0,0 +1,82 @@
+//
+// impl/src.hpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SRC_HPP
+#define ASIO_IMPL_SRC_HPP
+
+#define ASIO_SOURCE
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# error Do not compile Asio library source with ASIO_HEADER_ONLY defined
+#endif
+
+#include "asio/impl/error.ipp"
+#include "asio/impl/error_code.ipp"
+#include "asio/impl/execution_context.ipp"
+#include "asio/impl/executor.ipp"
+#include "asio/impl/handler_alloc_hook.ipp"
+#include "asio/impl/io_context.ipp"
+#include "asio/impl/serial_port_base.ipp"
+#include "asio/impl/system_context.ipp"
+#include "asio/impl/thread_pool.ipp"
+#include "asio/detail/impl/buffer_sequence_adapter.ipp"
+#include "asio/detail/impl/descriptor_ops.ipp"
+#include "asio/detail/impl/dev_poll_reactor.ipp"
+#include "asio/detail/impl/epoll_reactor.ipp"
+#include "asio/detail/impl/eventfd_select_interrupter.ipp"
+#include "asio/detail/impl/handler_tracking.ipp"
+#include "asio/detail/impl/kqueue_reactor.ipp"
+#include "asio/detail/impl/null_event.ipp"
+#include "asio/detail/impl/pipe_select_interrupter.ipp"
+#include "asio/detail/impl/posix_event.ipp"
+#include "asio/detail/impl/posix_mutex.ipp"
+#include "asio/detail/impl/posix_thread.ipp"
+#include "asio/detail/impl/posix_tss_ptr.ipp"
+#include "asio/detail/impl/reactive_descriptor_service.ipp"
+#include "asio/detail/impl/reactive_serial_port_service.ipp"
+#include "asio/detail/impl/reactive_socket_service_base.ipp"
+#include "asio/detail/impl/resolver_service_base.ipp"
+#include "asio/detail/impl/scheduler.ipp"
+#include "asio/detail/impl/select_reactor.ipp"
+#include "asio/detail/impl/service_registry.ipp"
+#include "asio/detail/impl/signal_set_service.ipp"
+#include "asio/detail/impl/socket_ops.ipp"
+#include "asio/detail/impl/socket_select_interrupter.ipp"
+#include "asio/detail/impl/strand_executor_service.ipp"
+#include "asio/detail/impl/strand_service.ipp"
+#include "asio/detail/impl/throw_error.ipp"
+#include "asio/detail/impl/timer_queue_ptime.ipp"
+#include "asio/detail/impl/timer_queue_set.ipp"
+#include "asio/detail/impl/win_iocp_handle_service.ipp"
+#include "asio/detail/impl/win_iocp_io_context.ipp"
+#include "asio/detail/impl/win_iocp_serial_port_service.ipp"
+#include "asio/detail/impl/win_iocp_socket_service_base.ipp"
+#include "asio/detail/impl/win_event.ipp"
+#include "asio/detail/impl/win_mutex.ipp"
+#include "asio/detail/impl/win_object_handle_service.ipp"
+#include "asio/detail/impl/win_static_mutex.ipp"
+#include "asio/detail/impl/win_thread.ipp"
+#include "asio/detail/impl/win_tss_ptr.ipp"
+#include "asio/detail/impl/winrt_ssocket_service_base.ipp"
+#include "asio/detail/impl/winrt_timer_scheduler.ipp"
+#include "asio/detail/impl/winsock_init.ipp"
+#include "asio/generic/detail/impl/endpoint.ipp"
+#include "asio/ip/impl/address.ipp"
+#include "asio/ip/impl/address_v4.ipp"
+#include "asio/ip/impl/address_v6.ipp"
+#include "asio/ip/impl/host_name.ipp"
+#include "asio/ip/impl/network_v4.ipp"
+#include "asio/ip/impl/network_v6.ipp"
+#include "asio/ip/detail/impl/endpoint.ipp"
+#include "asio/local/detail/impl/endpoint.ipp"
+
+#endif // ASIO_IMPL_SRC_HPP
diff --git a/subprojects/asio/include/asio/impl/system_context.hpp b/subprojects/asio/include/asio/impl/system_context.hpp
new file mode 100644
index 000000000..87ffe76a2
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/system_context.hpp
@@ -0,0 +1,34 @@
+//
+// impl/system_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SYSTEM_CONTEXT_HPP
+#define ASIO_IMPL_SYSTEM_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/system_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+inline system_context::executor_type
+system_context::get_executor() ASIO_NOEXCEPT
+{
+  return system_executor();
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_SYSTEM_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/impl/system_context.ipp b/subprojects/asio/include/asio/impl/system_context.ipp
new file mode 100644
index 000000000..8ad5e4188
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/system_context.ipp
@@ -0,0 +1,73 @@
+//
+// impl/system_context.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SYSTEM_CONTEXT_IPP
+#define ASIO_IMPL_SYSTEM_CONTEXT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/system_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+struct system_context::thread_function
+{
+  detail::scheduler* scheduler_;
+
+  void operator()()
+  {
+    asio::error_code ec;
+    scheduler_->run(ec);
+  }
+};
+
+system_context::system_context()
+  : scheduler_(use_service<detail::scheduler>(*this))
+{
+  scheduler_.work_started();
+
+  thread_function f = { &scheduler_ };
+  std::size_t num_threads = detail::thread::hardware_concurrency() * 2;
+  threads_.create_threads(f, num_threads ? num_threads : 2);
+}
+
+system_context::~system_context()
+{
+  scheduler_.work_finished();
+  scheduler_.stop();
+  threads_.join();
+}
+
+void system_context::stop()
+{
+  scheduler_.stop();
+}
+
+bool system_context::stopped() const ASIO_NOEXCEPT
+{
+  return scheduler_.stopped();
+}
+
+void system_context::join()
+{
+  scheduler_.work_finished();
+  threads_.join();
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_SYSTEM_CONTEXT_IPP
diff --git a/subprojects/asio/include/asio/impl/system_executor.hpp b/subprojects/asio/include/asio/impl/system_executor.hpp
new file mode 100644
index 000000000..ac4861f56
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/system_executor.hpp
@@ -0,0 +1,85 @@
+//
+// impl/system_executor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SYSTEM_EXECUTOR_HPP
+#define ASIO_IMPL_SYSTEM_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/executor_op.hpp"
+#include "asio/detail/global.hpp"
+#include "asio/detail/recycling_allocator.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/system_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+inline system_context& system_executor::context() const ASIO_NOEXCEPT
+{
+  return detail::global<system_context>();
+}
+
+template <typename Function, typename Allocator>
+void system_executor::dispatch(
+    ASIO_MOVE_ARG(Function) f, const Allocator&) const
+{
+  typename decay<Function>::type tmp(ASIO_MOVE_CAST(Function)(f));
+  asio_handler_invoke_helpers::invoke(tmp, tmp);
+}
+
+template <typename Function, typename Allocator>
+void system_executor::post(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  system_context& ctx = detail::global<system_context>();
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((ctx, *p.p,
+        "system_executor", &this->context(), 0, "post"));
+
+  ctx.scheduler_.post_immediate_completion(p.p, false);
+  p.v = p.p = 0;
+}
+
+template <typename Function, typename Allocator>
+void system_executor::defer(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  system_context& ctx = detail::global<system_context>();
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((ctx, *p.p,
+        "system_executor", &this->context(), 0, "defer"));
+
+  ctx.scheduler_.post_immediate_completion(p.p, true);
+  p.v = p.p = 0;
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_SYSTEM_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/impl/thread_pool.hpp b/subprojects/asio/include/asio/impl/thread_pool.hpp
new file mode 100644
index 000000000..058e3771b
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/thread_pool.hpp
@@ -0,0 +1,127 @@
+//
+// impl/thread_pool.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_THREAD_POOL_HPP
+#define ASIO_IMPL_THREAD_POOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/executor_op.hpp"
+#include "asio/detail/fenced_block.hpp"
+#include "asio/detail/recycling_allocator.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+inline thread_pool::executor_type
+thread_pool::get_executor() ASIO_NOEXCEPT
+{
+  return executor_type(*this);
+}
+
+inline thread_pool&
+thread_pool::executor_type::context() const ASIO_NOEXCEPT
+{
+  return pool_;
+}
+
+inline void
+thread_pool::executor_type::on_work_started() const ASIO_NOEXCEPT
+{
+  pool_.scheduler_.work_started();
+}
+
+inline void thread_pool::executor_type::on_work_finished()
+const ASIO_NOEXCEPT
+{
+  pool_.scheduler_.work_finished();
+}
+
+template <typename Function, typename Allocator>
+void thread_pool::executor_type::dispatch(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Invoke immediately if we are already inside the thread pool.
+  if (pool_.scheduler_.can_dispatch())
+  {
+    // Make a local, non-const copy of the function.
+    function_type tmp(ASIO_MOVE_CAST(Function)(f));
+
+    detail::fenced_block b(detail::fenced_block::full);
+    asio_handler_invoke_helpers::invoke(tmp, tmp);
+    return;
+  }
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((pool_, *p.p,
+        "thread_pool", &this->context(), 0, "dispatch"));
+
+  pool_.scheduler_.post_immediate_completion(p.p, false);
+  p.v = p.p = 0;
+}
+
+template <typename Function, typename Allocator>
+void thread_pool::executor_type::post(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((pool_, *p.p,
+        "thread_pool", &this->context(), 0, "post"));
+
+  pool_.scheduler_.post_immediate_completion(p.p, false);
+  p.v = p.p = 0;
+}
+
+template <typename Function, typename Allocator>
+void thread_pool::executor_type::defer(
+    ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+{
+  typedef typename decay<Function>::type function_type;
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<function_type, Allocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(ASIO_MOVE_CAST(Function)(f), a);
+
+  ASIO_HANDLER_CREATION((pool_, *p.p,
+        "thread_pool", &this->context(), 0, "defer"));
+
+  pool_.scheduler_.post_immediate_completion(p.p, true);
+  p.v = p.p = 0;
+}
+
+inline bool
+thread_pool::executor_type::running_in_this_thread() const ASIO_NOEXCEPT
+{
+  return pool_.scheduler_.can_dispatch();
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_THREAD_POOL_HPP
diff --git a/subprojects/asio/include/asio/impl/thread_pool.ipp b/subprojects/asio/include/asio/impl/thread_pool.ipp
new file mode 100644
index 000000000..89583c14a
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/thread_pool.ipp
@@ -0,0 +1,76 @@
+//
+// impl/thread_pool.ipp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_THREAD_POOL_IPP
+#define ASIO_IMPL_THREAD_POOL_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/thread_pool.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+struct thread_pool::thread_function
+{
+  detail::scheduler* scheduler_;
+
+  void operator()()
+  {
+    asio::error_code ec;
+    scheduler_->run(ec);
+  }
+};
+
+thread_pool::thread_pool()
+  : scheduler_(use_service<detail::scheduler>(*this))
+{
+  scheduler_.work_started();
+
+  thread_function f = { &scheduler_ };
+  std::size_t num_threads = detail::thread::hardware_concurrency() * 2;
+  threads_.create_threads(f, num_threads ? num_threads : 2);
+}
+
+thread_pool::thread_pool(std::size_t num_threads)
+  : scheduler_(use_service<detail::scheduler>(*this))
+{
+  scheduler_.work_started();
+
+  thread_function f = { &scheduler_ };
+  threads_.create_threads(f, num_threads);
+}
+
+thread_pool::~thread_pool()
+{
+  stop();
+  join();
+}
+
+void thread_pool::stop()
+{
+  scheduler_.stop();
+}
+
+void thread_pool::join()
+{
+  scheduler_.work_finished();
+  threads_.join();
+}
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_THREAD_POOL_IPP
diff --git a/subprojects/asio/include/asio/impl/use_future.hpp b/subprojects/asio/include/asio/impl/use_future.hpp
new file mode 100644
index 000000000..40bf7a47a
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/use_future.hpp
@@ -0,0 +1,937 @@
+//
+// impl/use_future.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_USE_FUTURE_HPP
+#define ASIO_IMPL_USE_FUTURE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <tuple>
+#include "asio/async_result.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/error_code.hpp"
+#include "asio/packaged_task.hpp"
+#include "asio/system_error.hpp"
+#include "asio/system_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename T, typename F, typename... Args>
+inline void promise_invoke_and_set(std::promise<T>& p,
+    F& f, ASIO_MOVE_ARG(Args)... args)
+{
+#if !defined(ASIO_NO_EXCEPTIONS)
+  try
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+  {
+    p.set_value(f(ASIO_MOVE_CAST(Args)(args)...));
+  }
+#if !defined(ASIO_NO_EXCEPTIONS)
+  catch (...)
+  {
+    p.set_exception(std::current_exception());
+  }
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+}
+
+template <typename F, typename... Args>
+inline void promise_invoke_and_set(std::promise<void>& p,
+    F& f, ASIO_MOVE_ARG(Args)... args)
+{
+#if !defined(ASIO_NO_EXCEPTIONS)
+  try
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+  {
+    f(ASIO_MOVE_CAST(Args)(args)...);
+    p.set_value();
+  }
+#if !defined(ASIO_NO_EXCEPTIONS)
+  catch (...)
+  {
+    p.set_exception(std::current_exception());
+  }
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+}
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename T, typename F>
+inline void promise_invoke_and_set(std::promise<T>& p, F& f)
+{
+#if !defined(ASIO_NO_EXCEPTIONS)
+  try
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+  {
+    p.set_value(f());
+  }
+#if !defined(ASIO_NO_EXCEPTIONS)
+  catch (...)
+  {
+    p.set_exception(std::current_exception());
+  }
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+}
+
+template <typename F, typename Args>
+inline void promise_invoke_and_set(std::promise<void>& p, F& f)
+{
+#if !defined(ASIO_NO_EXCEPTIONS)
+  try
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+  {
+    f();
+    p.set_value();
+#if !defined(ASIO_NO_EXCEPTIONS)
+  }
+  catch (...)
+  {
+    p.set_exception(std::current_exception());
+  }
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+}
+
+#if defined(ASIO_NO_EXCEPTIONS)
+
+#define ASIO_PRIVATE_PROMISE_INVOKE_DEF(n) \
+  template <typename T, typename F, ASIO_VARIADIC_TPARAMS(n)> \
+  inline void promise_invoke_and_set(std::promise<T>& p, \
+      F& f, ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    p.set_value(f(ASIO_VARIADIC_MOVE_ARGS(n))); \
+  } \
+  \
+  template <typename F, ASIO_VARIADIC_TPARAMS(n)> \
+  inline void promise_invoke_and_set(std::promise<void>& p, \
+      F& f, ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    f(ASIO_VARIADIC_MOVE_ARGS(n)); \
+    p.set_value(); \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_PROMISE_INVOKE_DEF)
+#undef ASIO_PRIVATE_PROMISE_INVOKE_DEF
+
+#else // defined(ASIO_NO_EXCEPTIONS)
+
+#define ASIO_PRIVATE_PROMISE_INVOKE_DEF(n) \
+  template <typename T, typename F, ASIO_VARIADIC_TPARAMS(n)> \
+  inline void promise_invoke_and_set(std::promise<T>& p, \
+      F& f, ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    try \
+    { \
+      p.set_value(f(ASIO_VARIADIC_MOVE_ARGS(n))); \
+    } \
+    catch (...) \
+    { \
+      p.set_exception(std::current_exception()); \
+    } \
+  } \
+  \
+  template <typename F, ASIO_VARIADIC_TPARAMS(n)> \
+  inline void promise_invoke_and_set(std::promise<void>& p, \
+      F& f, ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  { \
+    try \
+    { \
+      f(ASIO_VARIADIC_MOVE_ARGS(n)); \
+      p.set_value(); \
+    } \
+    catch (...) \
+    { \
+      p.set_exception(std::current_exception()); \
+    } \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_PROMISE_INVOKE_DEF)
+#undef ASIO_PRIVATE_PROMISE_INVOKE_DEF
+
+#endif // defined(ASIO_NO_EXCEPTIONS)
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+// A function object adapter to invoke a nullary function object and capture
+// any exception thrown into a promise.
+template <typename T, typename F>
+class promise_invoker
+{
+public:
+  promise_invoker(const shared_ptr<std::promise<T> >& p,
+      ASIO_MOVE_ARG(F) f)
+    : p_(p), f_(ASIO_MOVE_CAST(F)(f))
+  {
+  }
+
+  void operator()()
+  {
+#if !defined(ASIO_NO_EXCEPTIONS)
+    try
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+    {
+      f_();
+    }
+#if !defined(ASIO_NO_EXCEPTIONS)
+    catch (...)
+    {
+      p_->set_exception(std::current_exception());
+    }
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+  }
+
+private:
+  shared_ptr<std::promise<T> > p_;
+  typename decay<F>::type f_;
+};
+
+// An executor that adapts the system_executor to capture any exeption thrown
+// by a submitted function object and save it into a promise.
+template <typename T>
+class promise_executor
+{
+public:
+  explicit promise_executor(const shared_ptr<std::promise<T> >& p)
+    : p_(p)
+  {
+  }
+
+  execution_context& context() const ASIO_NOEXCEPT
+  {
+    return system_executor().context();
+  }
+
+  void on_work_started() const ASIO_NOEXCEPT {}
+  void on_work_finished() const ASIO_NOEXCEPT {}
+
+  template <typename F, typename A>
+  void dispatch(ASIO_MOVE_ARG(F) f, const A&) const
+  {
+    promise_invoker<T, F>(p_, ASIO_MOVE_CAST(F)(f))();
+  }
+
+  template <typename F, typename A>
+  void post(ASIO_MOVE_ARG(F) f, const A& a) const
+  {
+    system_executor().post(
+        promise_invoker<T, F>(p_, ASIO_MOVE_CAST(F)(f)), a);
+  }
+
+  template <typename F, typename A>
+  void defer(ASIO_MOVE_ARG(F) f, const A& a) const
+  {
+    system_executor().defer(
+        promise_invoker<T, F>(p_, ASIO_MOVE_CAST(F)(f)), a);
+  }
+
+  friend bool operator==(const promise_executor& a,
+      const promise_executor& b) ASIO_NOEXCEPT
+  {
+    return a.p_ == b.p_;
+  }
+
+  friend bool operator!=(const promise_executor& a,
+      const promise_executor& b) ASIO_NOEXCEPT
+  {
+    return a.p_ != b.p_;
+  }
+
+private:
+  shared_ptr<std::promise<T> > p_;
+};
+
+// The base class for all completion handlers that create promises.
+template <typename T>
+class promise_creator
+{
+public:
+  typedef promise_executor<T> executor_type;
+
+  executor_type get_executor() const ASIO_NOEXCEPT
+  {
+    return executor_type(p_);
+  }
+
+  typedef std::future<T> future_type;
+
+  future_type get_future()
+  {
+    return p_->get_future();
+  }
+
+protected:
+  template <typename Allocator>
+  void create_promise(const Allocator& a)
+  {
+    ASIO_REBIND_ALLOC(Allocator, char) b(a);
+    p_ = std::allocate_shared<std::promise<T>>(b, std::allocator_arg, b);
+  }
+
+  shared_ptr<std::promise<T> > p_;
+};
+
+// For completion signature void().
+class promise_handler_0
+  : public promise_creator<void>
+{
+public:
+  void operator()()
+  {
+    this->p_->set_value();
+  }
+};
+
+// For completion signature void(error_code).
+class promise_handler_ec_0
+  : public promise_creator<void>
+{
+public:
+  void operator()(const asio::error_code& ec)
+  {
+    if (ec)
+    {
+      this->p_->set_exception(
+          std::make_exception_ptr(
+            asio::system_error(ec)));
+    }
+    else
+    {
+      this->p_->set_value();
+    }
+  }
+};
+
+// For completion signature void(exception_ptr).
+class promise_handler_ex_0
+  : public promise_creator<void>
+{
+public:
+  void operator()(const std::exception_ptr& ex)
+  {
+    if (ex)
+    {
+      this->p_->set_exception(ex);
+    }
+    else
+    {
+      this->p_->set_value();
+    }
+  }
+};
+
+// For completion signature void(T).
+template <typename T>
+class promise_handler_1
+  : public promise_creator<T>
+{
+public:
+  template <typename Arg>
+  void operator()(ASIO_MOVE_ARG(Arg) arg)
+  {
+    this->p_->set_value(ASIO_MOVE_CAST(Arg)(arg));
+  }
+};
+
+// For completion signature void(error_code, T).
+template <typename T>
+class promise_handler_ec_1
+  : public promise_creator<T>
+{
+public:
+  template <typename Arg>
+  void operator()(const asio::error_code& ec,
+      ASIO_MOVE_ARG(Arg) arg)
+  {
+    if (ec)
+    {
+      this->p_->set_exception(
+          std::make_exception_ptr(
+            asio::system_error(ec)));
+    }
+    else
+      this->p_->set_value(ASIO_MOVE_CAST(Arg)(arg));
+  }
+};
+
+// For completion signature void(exception_ptr, T).
+template <typename T>
+class promise_handler_ex_1
+  : public promise_creator<T>
+{
+public:
+  template <typename Arg>
+  void operator()(const std::exception_ptr& ex,
+      ASIO_MOVE_ARG(Arg) arg)
+  {
+    if (ex)
+      this->p_->set_exception(ex);
+    else
+      this->p_->set_value(ASIO_MOVE_CAST(Arg)(arg));
+  }
+};
+
+// For completion signature void(T1, ..., Tn);
+template <typename T>
+class promise_handler_n
+  : public promise_creator<T>
+{
+public:
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename... Args>
+  void operator()(ASIO_MOVE_ARG(Args)... args)
+  {
+    this->p_->set_value(
+        std::forward_as_tuple(
+          ASIO_MOVE_CAST(Args)(args)...));
+  }
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#define ASIO_PRIVATE_CALL_OP_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  void operator()(ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  {\
+    this->p_->set_value( \
+        std::forward_as_tuple( \
+          ASIO_VARIADIC_MOVE_ARGS(n))); \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_CALL_OP_DEF)
+#undef ASIO_PRIVATE_CALL_OP_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+};
+
+// For completion signature void(error_code, T1, ..., Tn);
+template <typename T>
+class promise_handler_ec_n
+  : public promise_creator<T>
+{
+public:
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename... Args>
+  void operator()(const asio::error_code& ec,
+      ASIO_MOVE_ARG(Args)... args)
+  {
+    if (ec)
+    {
+      this->p_->set_exception(
+          std::make_exception_ptr(
+            asio::system_error(ec)));
+    }
+    else
+    {
+      this->p_->set_value(
+          std::forward_as_tuple(
+            ASIO_MOVE_CAST(Args)(args)...));
+    }
+  }
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#define ASIO_PRIVATE_CALL_OP_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  void operator()(const asio::error_code& ec, \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  {\
+    if (ec) \
+    { \
+      this->p_->set_exception( \
+          std::make_exception_ptr( \
+            asio::system_error(ec))); \
+    } \
+    else \
+    { \
+      this->p_->set_value( \
+          std::forward_as_tuple( \
+            ASIO_VARIADIC_MOVE_ARGS(n))); \
+    } \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_CALL_OP_DEF)
+#undef ASIO_PRIVATE_CALL_OP_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+};
+
+// For completion signature void(exception_ptr, T1, ..., Tn);
+template <typename T>
+class promise_handler_ex_n
+  : public promise_creator<T>
+{
+public:
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename... Args>
+  void operator()(const std::exception_ptr& ex,
+      ASIO_MOVE_ARG(Args)... args)
+  {
+    if (ex)
+      this->p_->set_exception(ex);
+    else
+    {
+      this->p_->set_value(
+          std::forward_as_tuple(
+            ASIO_MOVE_CAST(Args)(args)...));
+    }
+  }
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#define ASIO_PRIVATE_CALL_OP_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  void operator()(const std::exception_ptr& ex, \
+      ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  {\
+    if (ex) \
+      this->p_->set_exception(ex); \
+    else \
+    { \
+      this->p_->set_value( \
+          std::forward_as_tuple( \
+            ASIO_VARIADIC_MOVE_ARGS(n))); \
+    } \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_CALL_OP_DEF)
+#undef ASIO_PRIVATE_CALL_OP_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+};
+
+// Helper template to choose the appropriate concrete promise handler
+// implementation based on the supplied completion signature.
+template <typename> class promise_handler_selector;
+
+template <>
+class promise_handler_selector<void()>
+  : public promise_handler_0 {};
+
+template <>
+class promise_handler_selector<void(asio::error_code)>
+  : public promise_handler_ec_0 {};
+
+template <>
+class promise_handler_selector<void(std::exception_ptr)>
+  : public promise_handler_ex_0 {};
+
+template <typename Arg>
+class promise_handler_selector<void(Arg)>
+  : public promise_handler_1<Arg> {};
+
+template <typename Arg>
+class promise_handler_selector<void(asio::error_code, Arg)>
+  : public promise_handler_ec_1<Arg> {};
+
+template <typename Arg>
+class promise_handler_selector<void(std::exception_ptr, Arg)>
+  : public promise_handler_ex_1<Arg> {};
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename... Arg>
+class promise_handler_selector<void(Arg...)>
+  : public promise_handler_n<std::tuple<Arg...> > {};
+
+template <typename... Arg>
+class promise_handler_selector<void(asio::error_code, Arg...)>
+  : public promise_handler_ec_n<std::tuple<Arg...> > {};
+
+template <typename... Arg>
+class promise_handler_selector<void(std::exception_ptr, Arg...)>
+  : public promise_handler_ex_n<std::tuple<Arg...> > {};
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#define ASIO_PRIVATE_PROMISE_SELECTOR_DEF(n) \
+  template <typename Arg, ASIO_VARIADIC_TPARAMS(n)> \
+  class promise_handler_selector< \
+    void(Arg, ASIO_VARIADIC_TARGS(n))> \
+      : public promise_handler_n< \
+        std::tuple<Arg, ASIO_VARIADIC_TARGS(n)> > {}; \
+  \
+  template <typename Arg, ASIO_VARIADIC_TPARAMS(n)> \
+  class promise_handler_selector< \
+    void(asio::error_code, Arg, ASIO_VARIADIC_TARGS(n))> \
+      : public promise_handler_ec_n< \
+        std::tuple<Arg, ASIO_VARIADIC_TARGS(n)> > {}; \
+  \
+  template <typename Arg, ASIO_VARIADIC_TPARAMS(n)> \
+  class promise_handler_selector< \
+    void(std::exception_ptr, Arg, ASIO_VARIADIC_TARGS(n))> \
+      : public promise_handler_ex_n< \
+        std::tuple<Arg, ASIO_VARIADIC_TARGS(n)> > {}; \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_PROMISE_SELECTOR_DEF)
+#undef ASIO_PRIVATE_PROMISE_SELECTOR_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+// Completion handlers produced from the use_future completion token, when not
+// using use_future::operator().
+template <typename Signature, typename Allocator>
+class promise_handler
+  : public promise_handler_selector<Signature>
+{
+public:
+  typedef Allocator allocator_type;
+  typedef void result_type;
+
+  promise_handler(use_future_t<Allocator> u)
+    : allocator_(u.get_allocator())
+  {
+    this->create_promise(allocator_);
+  }
+
+  allocator_type get_allocator() const ASIO_NOEXCEPT
+  {
+    return allocator_;
+  }
+
+private:
+  Allocator allocator_;
+};
+
+template <typename Function, typename Signature, typename Allocator>
+inline void asio_handler_invoke(Function& f,
+    promise_handler<Signature, Allocator>* h)
+{
+  typename promise_handler<Signature, Allocator>::executor_type
+    ex(h->get_executor());
+  ex.dispatch(ASIO_MOVE_CAST(Function)(f), std::allocator<void>());
+}
+
+template <typename Function, typename Signature, typename Allocator>
+inline void asio_handler_invoke(const Function& f,
+    promise_handler<Signature, Allocator>* h)
+{
+  typename promise_handler<Signature, Allocator>::executor_type
+    ex(h->get_executor());
+  ex.dispatch(f, std::allocator<void>());
+}
+
+// Helper base class for async_result specialisation.
+template <typename Signature, typename Allocator>
+class promise_async_result
+{
+public:
+  typedef promise_handler<Signature, Allocator> completion_handler_type;
+  typedef typename completion_handler_type::future_type return_type;
+
+  explicit promise_async_result(completion_handler_type& h)
+    : future_(h.get_future())
+  {
+  }
+
+  return_type get()
+  {
+    return ASIO_MOVE_CAST(return_type)(future_);
+  }
+
+private:
+  return_type future_;
+};
+
+// Return value from use_future::operator().
+template <typename Function, typename Allocator>
+class packaged_token
+{
+public:
+  packaged_token(Function f, const Allocator& a)
+    : function_(ASIO_MOVE_CAST(Function)(f)),
+      allocator_(a)
+  {
+  }
+
+//private:
+  Function function_;
+  Allocator allocator_;
+};
+
+// Completion handlers produced from the use_future completion token, when
+// using use_future::operator().
+template <typename Function, typename Allocator, typename Result>
+class packaged_handler
+  : public promise_creator<Result>
+{
+public:
+  typedef Allocator allocator_type;
+  typedef void result_type;
+
+  packaged_handler(packaged_token<Function, Allocator> t)
+    : function_(ASIO_MOVE_CAST(Function)(t.function_)),
+      allocator_(t.allocator_)
+  {
+    this->create_promise(allocator_);
+  }
+
+  allocator_type get_allocator() const ASIO_NOEXCEPT
+  {
+    return allocator_;
+  }
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename... Args>
+  void operator()(ASIO_MOVE_ARG(Args)... args)
+  {
+    (promise_invoke_and_set)(*this->p_,
+        function_, ASIO_MOVE_CAST(Args)(args)...);
+  }
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  void operator()()
+  {
+    (promise_invoke_and_set)(*this->p_, function_);
+  }
+
+#define ASIO_PRIVATE_CALL_OP_DEF(n) \
+  template <ASIO_VARIADIC_TPARAMS(n)> \
+  void operator()(ASIO_VARIADIC_MOVE_PARAMS(n)) \
+  {\
+    (promise_invoke_and_set)(*this->p_, \
+        function_, ASIO_VARIADIC_MOVE_ARGS(n)); \
+  } \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_CALL_OP_DEF)
+#undef ASIO_PRIVATE_CALL_OP_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+private:
+  Function function_;
+  Allocator allocator_;
+};
+
+template <typename Function,
+    typename Function1, typename Allocator, typename Result>
+inline void asio_handler_invoke(Function& f,
+    packaged_handler<Function1, Allocator, Result>* h)
+{
+  typename packaged_handler<Function1, Allocator, Result>::executor_type
+    ex(h->get_executor());
+  ex.dispatch(ASIO_MOVE_CAST(Function)(f), std::allocator<void>());
+}
+
+template <typename Function,
+    typename Function1, typename Allocator, typename Result>
+inline void asio_handler_invoke(const Function& f,
+    packaged_handler<Function1, Allocator, Result>* h)
+{
+  typename packaged_handler<Function1, Allocator, Result>::executor_type
+    ex(h->get_executor());
+  ex.dispatch(f, std::allocator<void>());
+}
+
+// Helper base class for async_result specialisation.
+template <typename Function, typename Allocator, typename Result>
+class packaged_async_result
+{
+public:
+  typedef packaged_handler<Function, Allocator, Result> completion_handler_type;
+  typedef typename completion_handler_type::future_type return_type;
+
+  explicit packaged_async_result(completion_handler_type& h)
+    : future_(h.get_future())
+  {
+  }
+
+  return_type get()
+  {
+    return ASIO_MOVE_CAST(return_type)(future_);
+  }
+
+private:
+  return_type future_;
+};
+
+} // namespace detail
+
+template <typename Allocator> template <typename Function>
+inline detail::packaged_token<typename decay<Function>::type, Allocator>
+use_future_t<Allocator>::operator()(ASIO_MOVE_ARG(Function) f) const
+{
+  return detail::packaged_token<typename decay<Function>::type, Allocator>(
+      ASIO_MOVE_CAST(Function)(f), allocator_);
+}
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename Allocator, typename Result, typename... Args>
+class async_result<use_future_t<Allocator>, Result(Args...)>
+  : public detail::promise_async_result<
+      void(typename decay<Args>::type...), Allocator>
+{
+public:
+  explicit async_result(
+    typename detail::promise_async_result<void(typename decay<Args>::type...),
+      Allocator>::completion_handler_type& h)
+    : detail::promise_async_result<
+        void(typename decay<Args>::type...), Allocator>(h)
+  {
+  }
+};
+
+template <typename Function, typename Allocator,
+    typename Result, typename... Args>
+class async_result<detail::packaged_token<Function, Allocator>, Result(Args...)>
+  : public detail::packaged_async_result<Function, Allocator,
+      typename result_of<Function(Args...)>::type>
+{
+public:
+  explicit async_result(
+    typename detail::packaged_async_result<Function, Allocator,
+      typename result_of<Function(Args...)>::type>::completion_handler_type& h)
+    : detail::packaged_async_result<Function, Allocator,
+        typename result_of<Function(Args...)>::type>(h)
+  {
+  }
+};
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+template <typename Allocator, typename Result>
+class async_result<use_future_t<Allocator>, Result()>
+  : public detail::promise_async_result<void(), Allocator>
+{
+public:
+  explicit async_result(
+    typename detail::promise_async_result<
+      void(), Allocator>::completion_handler_type& h)
+    : detail::promise_async_result<void(), Allocator>(h)
+  {
+  }
+};
+
+template <typename Function, typename Allocator, typename Result>
+class async_result<detail::packaged_token<Function, Allocator>, Result()>
+  : public detail::packaged_async_result<Function, Allocator,
+      typename result_of<Function()>::type>
+{
+public:
+  explicit async_result(
+    typename detail::packaged_async_result<Function, Allocator,
+      typename result_of<Function()>::type>::completion_handler_type& h)
+    : detail::packaged_async_result<Function, Allocator,
+        typename result_of<Function()>::type>(h)
+  {
+  }
+};
+
+#define ASIO_PRIVATE_ASYNC_RESULT_DEF(n) \
+  template <typename Allocator, \
+      typename Result, ASIO_VARIADIC_TPARAMS(n)> \
+  class async_result<use_future_t<Allocator>, \
+      Result(ASIO_VARIADIC_TARGS(n))> \
+    : public detail::promise_async_result< \
+        void(ASIO_VARIADIC_DECAY(n)), Allocator> \
+  { \
+  public: \
+    explicit async_result( \
+      typename detail::promise_async_result< \
+        void(ASIO_VARIADIC_DECAY(n)), \
+        Allocator>::completion_handler_type& h) \
+      : detail::promise_async_result< \
+          void(ASIO_VARIADIC_DECAY(n)), Allocator>(h) \
+    { \
+    } \
+  }; \
+  \
+  template <typename Function, typename Allocator, \
+      typename Result, ASIO_VARIADIC_TPARAMS(n)> \
+  class async_result<detail::packaged_token<Function, Allocator>, \
+      Result(ASIO_VARIADIC_TARGS(n))> \
+    : public detail::packaged_async_result<Function, Allocator, \
+        typename result_of<Function(ASIO_VARIADIC_TARGS(n))>::type> \
+  { \
+  public: \
+    explicit async_result( \
+      typename detail::packaged_async_result<Function, Allocator, \
+        typename result_of<Function(ASIO_VARIADIC_TARGS(n))>::type \
+        >::completion_handler_type& h) \
+      : detail::packaged_async_result<Function, Allocator, \
+          typename result_of<Function(ASIO_VARIADIC_TARGS(n))>::type>(h) \
+    { \
+    } \
+  }; \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_RESULT_DEF)
+#undef ASIO_PRIVATE_ASYNC_RESULT_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+template <typename Allocator, typename Signature>
+struct handler_type<use_future_t<Allocator>, Signature>
+{
+  typedef typename async_result<use_future_t<Allocator>,
+    Signature>::completion_handler_type type;
+};
+
+template <typename Signature, typename Allocator>
+class async_result<detail::promise_handler<Signature, Allocator> >
+  : public detail::promise_async_result<Signature, Allocator>
+{
+public:
+  typedef typename detail::promise_async_result<
+    Signature, Allocator>::return_type type;
+
+  explicit async_result(
+    typename detail::promise_async_result<
+      Signature, Allocator>::completion_handler_type& h)
+    : detail::promise_async_result<Signature, Allocator>(h)
+  {
+  }
+};
+
+template <typename Function, typename Allocator, typename Signature>
+struct handler_type<detail::packaged_token<Function, Allocator>, Signature>
+{
+  typedef typename async_result<detail::packaged_token<Function, Allocator>,
+    Signature>::completion_handler_type type;
+};
+
+template <typename Function, typename Allocator, typename Result>
+class async_result<detail::packaged_handler<Function, Allocator, Result> >
+  : public detail::packaged_async_result<Function, Allocator, Result>
+{
+public:
+  typedef typename detail::packaged_async_result<
+    Function, Allocator, Result>::return_type type;
+
+  explicit async_result(
+    typename detail::packaged_async_result<
+      Function, Allocator, Result>::completion_handler_type& h)
+    : detail::packaged_async_result<Function, Allocator, Result>(h)
+  {
+  }
+};
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_USE_FUTURE_HPP
diff --git a/subprojects/asio/include/asio/impl/write.hpp b/subprojects/asio/include/asio/impl/write.hpp
new file mode 100644
index 000000000..d07e8d3e0
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/write.hpp
@@ -0,0 +1,674 @@
+//
+// impl/write.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_WRITE_HPP
+#define ASIO_IMPL_WRITE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/buffer.hpp"
+#include "asio/completion_condition.hpp"
+#include "asio/detail/array_fwd.hpp"
+#include "asio/detail/base_from_completion_cond.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/consuming_buffers.hpp"
+#include "asio/detail/dependent_type.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  template <typename SyncWriteStream, typename ConstBufferSequence,
+      typename ConstBufferIterator, typename CompletionCondition>
+  std::size_t write_buffer_sequence(SyncWriteStream& s,
+      const ConstBufferSequence& buffers, const ConstBufferIterator&,
+      CompletionCondition completion_condition, asio::error_code& ec)
+  {
+    ec = asio::error_code();
+    asio::detail::consuming_buffers<const_buffer,
+        ConstBufferSequence, ConstBufferIterator> tmp(buffers);
+    while (!tmp.empty())
+    {
+      if (std::size_t max_size = detail::adapt_completion_condition_result(
+            completion_condition(ec, tmp.total_consumed())))
+        tmp.consume(s.write_some(tmp.prepare(max_size), ec));
+      else
+        break;
+    }
+    return tmp.total_consumed();;
+  }
+} // namespace detail
+
+template <typename SyncWriteStream, typename ConstBufferSequence,
+    typename CompletionCondition>
+inline std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type*)
+{
+  return detail::write_buffer_sequence(s, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition, ec);
+}
+
+template <typename SyncWriteStream, typename ConstBufferSequence>
+inline std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write(s, buffers, transfer_all(), ec);
+  asio::detail::throw_error(ec, "write");
+  return bytes_transferred;
+}
+
+template <typename SyncWriteStream, typename ConstBufferSequence>
+inline std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type*)
+{
+  return write(s, buffers, transfer_all(), ec);
+}
+
+template <typename SyncWriteStream, typename ConstBufferSequence,
+    typename CompletionCondition>
+inline std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write(s, buffers, completion_condition, ec);
+  asio::detail::throw_error(ec, "write");
+  return bytes_transferred;
+}
+
+template <typename SyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition>
+std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  typename decay<DynamicBuffer>::type b(
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers));
+
+  std::size_t bytes_transferred = write(s, b.data(), completion_condition, ec);
+  b.consume(bytes_transferred);
+  return bytes_transferred;
+}
+
+template <typename SyncWriteStream, typename DynamicBuffer>
+inline std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      transfer_all(), ec);
+  asio::detail::throw_error(ec, "write");
+  return bytes_transferred;
+}
+
+template <typename SyncWriteStream, typename DynamicBuffer>
+inline std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  return write(s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      transfer_all(), ec);
+}
+
+template <typename SyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition>
+inline std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      completion_condition, ec);
+  asio::detail::throw_error(ec, "write");
+  return bytes_transferred;
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename SyncWriteStream, typename Allocator,
+    typename CompletionCondition>
+inline std::size_t write(SyncWriteStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, asio::error_code& ec)
+{
+  return write(s, basic_streambuf_ref<Allocator>(b), completion_condition, ec);
+}
+
+template <typename SyncWriteStream, typename Allocator>
+inline std::size_t write(SyncWriteStream& s,
+    asio::basic_streambuf<Allocator>& b)
+{
+  return write(s, basic_streambuf_ref<Allocator>(b));
+}
+
+template <typename SyncWriteStream, typename Allocator>
+inline std::size_t write(SyncWriteStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    asio::error_code& ec)
+{
+  return write(s, basic_streambuf_ref<Allocator>(b), ec);
+}
+
+template <typename SyncWriteStream, typename Allocator,
+    typename CompletionCondition>
+inline std::size_t write(SyncWriteStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition)
+{
+  return write(s, basic_streambuf_ref<Allocator>(b), completion_condition);
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+namespace detail
+{
+  template <typename AsyncWriteStream, typename ConstBufferSequence,
+      typename ConstBufferIterator, typename CompletionCondition,
+      typename WriteHandler>
+  class write_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    write_op(AsyncWriteStream& stream, const ConstBufferSequence& buffers,
+        CompletionCondition completion_condition, WriteHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        stream_(stream),
+        buffers_(buffers),
+        start_(0),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    write_op(const write_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        stream_(other.stream_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(other.handler_)
+    {
+    }
+
+    write_op(write_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        stream_(other.stream_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t max_size;
+      switch (start_ = start)
+      {
+        case 1:
+        max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        do
+        {
+          stream_.async_write_some(buffers_.prepare(max_size),
+              ASIO_MOVE_CAST(write_op)(*this));
+          return; default:
+          buffers_.consume(bytes_transferred);
+          if ((!ec && bytes_transferred == 0) || buffers_.empty())
+            break;
+          max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        } while (max_size > 0);
+
+        handler_(ec, buffers_.total_consumed());
+      }
+    }
+
+  //private:
+    AsyncWriteStream& stream_;
+    asio::detail::consuming_buffers<const_buffer,
+        ConstBufferSequence, ConstBufferIterator> buffers_;
+    int start_;
+    WriteHandler handler_;
+  };
+
+  template <typename AsyncWriteStream, typename ConstBufferSequence,
+      typename ConstBufferIterator, typename CompletionCondition,
+      typename WriteHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      write_op<AsyncWriteStream, ConstBufferSequence, ConstBufferIterator,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncWriteStream, typename ConstBufferSequence,
+      typename ConstBufferIterator, typename CompletionCondition,
+      typename WriteHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      write_op<AsyncWriteStream, ConstBufferSequence, ConstBufferIterator,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncWriteStream, typename ConstBufferSequence,
+      typename ConstBufferIterator, typename CompletionCondition,
+      typename WriteHandler>
+  inline bool asio_handler_is_continuation(
+      write_op<AsyncWriteStream, ConstBufferSequence, ConstBufferIterator,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncWriteStream,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline void asio_handler_invoke(Function& function,
+      write_op<AsyncWriteStream, ConstBufferSequence, ConstBufferIterator,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncWriteStream,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline void asio_handler_invoke(const Function& function,
+      write_op<AsyncWriteStream, ConstBufferSequence, ConstBufferIterator,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename AsyncWriteStream, typename ConstBufferSequence,
+      typename ConstBufferIterator, typename CompletionCondition,
+      typename WriteHandler>
+  inline void start_write_buffer_sequence_op(AsyncWriteStream& stream,
+      const ConstBufferSequence& buffers, const ConstBufferIterator&,
+      CompletionCondition completion_condition, WriteHandler& handler)
+  {
+    detail::write_op<AsyncWriteStream, ConstBufferSequence,
+      ConstBufferIterator, CompletionCondition, WriteHandler>(
+        stream, buffers, completion_condition, handler)(
+          asio::error_code(), 0, 1);
+  }
+
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncWriteStream, typename ConstBufferSequence,
+    typename ConstBufferIterator, typename CompletionCondition,
+    typename WriteHandler, typename Allocator>
+struct associated_allocator<
+    detail::write_op<AsyncWriteStream, ConstBufferSequence,
+      ConstBufferIterator, CompletionCondition, WriteHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<WriteHandler, Allocator>::type type;
+
+  static type get(
+      const detail::write_op<AsyncWriteStream, ConstBufferSequence,
+        ConstBufferIterator, CompletionCondition, WriteHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<WriteHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncWriteStream, typename ConstBufferSequence,
+    typename ConstBufferIterator, typename CompletionCondition,
+    typename WriteHandler, typename Executor>
+struct associated_executor<
+    detail::write_op<AsyncWriteStream, ConstBufferSequence,
+      ConstBufferIterator, CompletionCondition, WriteHandler>,
+    Executor>
+{
+  typedef typename associated_executor<WriteHandler, Executor>::type type;
+
+  static type get(
+      const detail::write_op<AsyncWriteStream, ConstBufferSequence,
+        ConstBufferIterator, CompletionCondition, WriteHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<WriteHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncWriteStream, typename ConstBufferSequence,
+  typename CompletionCondition, typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_write_buffer_sequence_op(s, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition,
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+template <typename AsyncWriteStream, typename ConstBufferSequence,
+    typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s, const ConstBufferSequence& buffers,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_write_buffer_sequence_op(s, buffers,
+      asio::buffer_sequence_begin(buffers), transfer_all(),
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+namespace detail
+{
+  template <typename AsyncWriteStream, typename DynamicBuffer,
+      typename CompletionCondition, typename WriteHandler>
+  class write_dynbuf_op
+  {
+  public:
+    template <typename BufferSequence>
+    write_dynbuf_op(AsyncWriteStream& stream,
+        ASIO_MOVE_ARG(BufferSequence) buffers,
+        CompletionCondition completion_condition, WriteHandler& handler)
+      : stream_(stream),
+        buffers_(ASIO_MOVE_CAST(BufferSequence)(buffers)),
+        completion_condition_(
+          ASIO_MOVE_CAST(CompletionCondition)(completion_condition)),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    write_dynbuf_op(const write_dynbuf_op& other)
+      : stream_(other.stream_),
+        buffers_(other.buffers_),
+        completion_condition_(other.completion_condition_),
+        handler_(other.handler_)
+    {
+    }
+
+    write_dynbuf_op(write_dynbuf_op&& other)
+      : stream_(other.stream_),
+        buffers_(ASIO_MOVE_CAST(DynamicBuffer)(other.buffers_)),
+        completion_condition_(
+          ASIO_MOVE_CAST(CompletionCondition)(
+            other.completion_condition_)),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      switch (start)
+      {
+        case 1:
+        async_write(stream_, buffers_.data(), completion_condition_,
+            ASIO_MOVE_CAST(write_dynbuf_op)(*this));
+        return; default:
+        buffers_.consume(bytes_transferred);
+        handler_(ec, static_cast<const std::size_t&>(bytes_transferred));
+      }
+    }
+
+  //private:
+    AsyncWriteStream& stream_;
+    DynamicBuffer buffers_;
+    CompletionCondition completion_condition_;
+    WriteHandler handler_;
+  };
+
+  template <typename AsyncWriteStream, typename DynamicBuffer,
+      typename CompletionCondition, typename WriteHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      write_dynbuf_op<AsyncWriteStream, DynamicBuffer,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncWriteStream, typename DynamicBuffer,
+      typename CompletionCondition, typename WriteHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      write_dynbuf_op<AsyncWriteStream, DynamicBuffer,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncWriteStream, typename DynamicBuffer,
+      typename CompletionCondition, typename WriteHandler>
+  inline bool asio_handler_is_continuation(
+      write_dynbuf_op<AsyncWriteStream, DynamicBuffer,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+        this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncWriteStream,
+      typename DynamicBuffer, typename CompletionCondition,
+      typename WriteHandler>
+  inline void asio_handler_invoke(Function& function,
+      write_dynbuf_op<AsyncWriteStream, DynamicBuffer,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncWriteStream,
+      typename DynamicBuffer, typename CompletionCondition,
+      typename WriteHandler>
+  inline void asio_handler_invoke(const Function& function,
+      write_dynbuf_op<AsyncWriteStream, DynamicBuffer,
+        CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition, typename WriteHandler, typename Allocator>
+struct associated_allocator<
+    detail::write_dynbuf_op<AsyncWriteStream,
+      DynamicBuffer, CompletionCondition, WriteHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<WriteHandler, Allocator>::type type;
+
+  static type get(
+      const detail::write_dynbuf_op<AsyncWriteStream,
+        DynamicBuffer, CompletionCondition, WriteHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<WriteHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition, typename WriteHandler, typename Executor>
+struct associated_executor<
+    detail::write_dynbuf_op<AsyncWriteStream,
+      DynamicBuffer, CompletionCondition, WriteHandler>,
+    Executor>
+{
+  typedef typename associated_executor<WriteHandler, Executor>::type type;
+
+  static type get(
+      const detail::write_dynbuf_op<AsyncWriteStream,
+        DynamicBuffer, CompletionCondition, WriteHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<WriteHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncWriteStream,
+    typename DynamicBuffer, typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  return async_write(s,
+      ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+      transfer_all(), ASIO_MOVE_CAST(WriteHandler)(handler));
+}
+
+template <typename AsyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition, typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type*)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::write_dynbuf_op<AsyncWriteStream,
+    typename decay<DynamicBuffer>::type,
+      CompletionCondition, ASIO_HANDLER_TYPE(
+        WriteHandler, void (asio::error_code, std::size_t))>(
+          s, ASIO_MOVE_CAST(DynamicBuffer)(buffers),
+            completion_condition, init.completion_handler)(
+              asio::error_code(), 0, 1);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename AsyncWriteStream, typename Allocator, typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  return async_write(s, basic_streambuf_ref<Allocator>(b),
+      ASIO_MOVE_CAST(WriteHandler)(handler));
+}
+
+template <typename AsyncWriteStream, typename Allocator,
+    typename CompletionCondition, typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  return async_write(s, basic_streambuf_ref<Allocator>(b),
+      completion_condition, ASIO_MOVE_CAST(WriteHandler)(handler));
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_WRITE_HPP
diff --git a/subprojects/asio/include/asio/impl/write_at.hpp b/subprojects/asio/include/asio/impl/write_at.hpp
new file mode 100644
index 000000000..cc6f336f1
--- /dev/null
+++ b/subprojects/asio/include/asio/impl/write_at.hpp
@@ -0,0 +1,572 @@
+//
+// impl/write_at.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_WRITE_AT_HPP
+#define ASIO_IMPL_WRITE_AT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/associated_allocator.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/buffer.hpp"
+#include "asio/completion_condition.hpp"
+#include "asio/detail/array_fwd.hpp"
+#include "asio/detail/base_from_completion_cond.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/consuming_buffers.hpp"
+#include "asio/detail/dependent_type.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
+      typename ConstBufferIterator, typename CompletionCondition>
+  std::size_t write_at_buffer_sequence(SyncRandomAccessWriteDevice& d,
+      uint64_t offset, const ConstBufferSequence& buffers,
+      const ConstBufferIterator&, CompletionCondition completion_condition,
+      asio::error_code& ec)
+  {
+    ec = asio::error_code();
+    asio::detail::consuming_buffers<const_buffer,
+        ConstBufferSequence, ConstBufferIterator> tmp(buffers);
+    while (!tmp.empty())
+    {
+      if (std::size_t max_size = detail::adapt_completion_condition_result(
+            completion_condition(ec, tmp.total_consumed())))
+      {
+        tmp.consume(d.write_some_at(offset + tmp.total_consumed(),
+              tmp.prepare(max_size), ec));
+      }
+      else
+        break;
+    }
+    return tmp.total_consumed();;
+  }
+} // namespace detail
+
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec)
+{
+  return detail::write_at_buffer_sequence(d, offset, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition, ec);
+}
+
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
+inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write_at(
+      d, offset, buffers, transfer_all(), ec);
+  asio::detail::throw_error(ec, "write_at");
+  return bytes_transferred;
+}
+
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
+inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    asio::error_code& ec)
+{
+  return write_at(d, offset, buffers, transfer_all(), ec);
+}
+
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition>
+inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write_at(
+      d, offset, buffers, completion_condition, ec);
+  asio::detail::throw_error(ec, "write_at");
+  return bytes_transferred;
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+template <typename SyncRandomAccessWriteDevice, typename Allocator,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, asio::error_code& ec)
+{
+  std::size_t bytes_transferred = write_at(
+      d, offset, b.data(), completion_condition, ec);
+  b.consume(bytes_transferred);
+  return bytes_transferred;
+}
+
+template <typename SyncRandomAccessWriteDevice, typename Allocator>
+inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write_at(d, offset, b, transfer_all(), ec);
+  asio::detail::throw_error(ec, "write_at");
+  return bytes_transferred;
+}
+
+template <typename SyncRandomAccessWriteDevice, typename Allocator>
+inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    asio::error_code& ec)
+{
+  return write_at(d, offset, b, transfer_all(), ec);
+}
+
+template <typename SyncRandomAccessWriteDevice, typename Allocator,
+    typename CompletionCondition>
+inline std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition)
+{
+  asio::error_code ec;
+  std::size_t bytes_transferred = write_at(
+      d, offset, b, completion_condition, ec);
+  asio::detail::throw_error(ec, "write_at");
+  return bytes_transferred;
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+namespace detail
+{
+  template <typename AsyncRandomAccessWriteDevice,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  class write_at_op
+    : detail::base_from_completion_cond<CompletionCondition>
+  {
+  public:
+    write_at_op(AsyncRandomAccessWriteDevice& device,
+        uint64_t offset, const ConstBufferSequence& buffers,
+        CompletionCondition completion_condition, WriteHandler& handler)
+      : detail::base_from_completion_cond<
+          CompletionCondition>(completion_condition),
+        device_(device),
+        offset_(offset),
+        buffers_(buffers),
+        start_(0),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    write_at_op(const write_at_op& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(other.handler_)
+    {
+    }
+
+    write_at_op(write_at_op&& other)
+      : detail::base_from_completion_cond<CompletionCondition>(other),
+        device_(other.device_),
+        offset_(other.offset_),
+        buffers_(other.buffers_),
+        start_(other.start_),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        std::size_t bytes_transferred, int start = 0)
+    {
+      std::size_t max_size;
+      switch (start_ = start)
+      {
+        case 1:
+        max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        do
+        {
+          device_.async_write_some_at(
+              offset_ + buffers_.total_consumed(), buffers_.prepare(max_size),
+              ASIO_MOVE_CAST(write_at_op)(*this));
+          return; default:
+          buffers_.consume(bytes_transferred);
+          if ((!ec && bytes_transferred == 0) || buffers_.empty())
+            break;
+          max_size = this->check_for_completion(ec, buffers_.total_consumed());
+        } while (max_size > 0);
+
+        handler_(ec, buffers_.total_consumed());
+      }
+    }
+
+  //private:
+    AsyncRandomAccessWriteDevice& device_;
+    uint64_t offset_;
+    asio::detail::consuming_buffers<const_buffer,
+        ConstBufferSequence, ConstBufferIterator> buffers_;
+    int start_;
+    WriteHandler handler_;
+  };
+
+  template <typename AsyncRandomAccessWriteDevice,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+        ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessWriteDevice,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+        ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessWriteDevice,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline bool asio_handler_is_continuation(
+      write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+        ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
+  {
+    return this_handler->start_ == 0 ? true
+      : asio_handler_cont_helpers::is_continuation(
+          this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessWriteDevice,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline void asio_handler_invoke(Function& function,
+      write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+        ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename AsyncRandomAccessWriteDevice,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline void asio_handler_invoke(const Function& function,
+      write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+        ConstBufferIterator, CompletionCondition, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename AsyncRandomAccessWriteDevice,
+      typename ConstBufferSequence, typename ConstBufferIterator,
+      typename CompletionCondition, typename WriteHandler>
+  inline void start_write_at_buffer_sequence_op(AsyncRandomAccessWriteDevice& d,
+      uint64_t offset, const ConstBufferSequence& buffers,
+      const ConstBufferIterator&, CompletionCondition completion_condition,
+      WriteHandler& handler)
+  {
+    detail::write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+      ConstBufferIterator, CompletionCondition, WriteHandler>(
+        d, offset, buffers, completion_condition, handler)(
+          asio::error_code(), 0, 1);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncRandomAccessWriteDevice,
+    typename ConstBufferSequence, typename ConstBufferIterator,
+    typename CompletionCondition, typename WriteHandler, typename Allocator>
+struct associated_allocator<
+    detail::write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+      ConstBufferIterator, CompletionCondition, WriteHandler>,
+    Allocator>
+{
+  typedef typename associated_allocator<WriteHandler, Allocator>::type type;
+
+  static type get(
+      const detail::write_at_op<AsyncRandomAccessWriteDevice,
+        ConstBufferSequence, ConstBufferIterator,
+        CompletionCondition, WriteHandler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<WriteHandler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename AsyncRandomAccessWriteDevice,
+    typename ConstBufferSequence, typename ConstBufferIterator,
+    typename CompletionCondition, typename WriteHandler, typename Executor>
+struct associated_executor<
+    detail::write_at_op<AsyncRandomAccessWriteDevice, ConstBufferSequence,
+      ConstBufferIterator, CompletionCondition, WriteHandler>,
+    Executor>
+{
+  typedef typename associated_executor<WriteHandler, Executor>::type type;
+
+  static type get(
+      const detail::write_at_op<AsyncRandomAccessWriteDevice,
+        ConstBufferSequence, ConstBufferIterator,
+        CompletionCondition, WriteHandler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<WriteHandler, Executor>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition, typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_write_at_buffer_sequence_op(d, offset, buffers,
+      asio::buffer_sequence_begin(buffers), completion_condition,
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  detail::start_write_at_buffer_sequence_op(d, offset, buffers,
+      asio::buffer_sequence_begin(buffers), transfer_all(),
+      init.completion_handler);
+
+  return init.result.get();
+}
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+namespace detail
+{
+  template <typename Allocator, typename WriteHandler>
+  class write_at_streambuf_op
+  {
+  public:
+    write_at_streambuf_op(
+        asio::basic_streambuf<Allocator>& streambuf,
+        WriteHandler& handler)
+      : streambuf_(streambuf),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(handler))
+    {
+    }
+
+#if defined(ASIO_HAS_MOVE)
+    write_at_streambuf_op(const write_at_streambuf_op& other)
+      : streambuf_(other.streambuf_),
+        handler_(other.handler_)
+    {
+    }
+
+    write_at_streambuf_op(write_at_streambuf_op&& other)
+      : streambuf_(other.streambuf_),
+        handler_(ASIO_MOVE_CAST(WriteHandler)(other.handler_))
+    {
+    }
+#endif // defined(ASIO_HAS_MOVE)
+
+    void operator()(const asio::error_code& ec,
+        const std::size_t bytes_transferred)
+    {
+      streambuf_.consume(bytes_transferred);
+      handler_(ec, bytes_transferred);
+    }
+
+  //private:
+    asio::basic_streambuf<Allocator>& streambuf_;
+    WriteHandler handler_;
+  };
+
+  template <typename Allocator, typename WriteHandler>
+  inline void* asio_handler_allocate(std::size_t size,
+      write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
+  {
+    return asio_handler_alloc_helpers::allocate(
+        size, this_handler->handler_);
+  }
+
+  template <typename Allocator, typename WriteHandler>
+  inline void asio_handler_deallocate(void* pointer, std::size_t size,
+      write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
+  {
+    asio_handler_alloc_helpers::deallocate(
+        pointer, size, this_handler->handler_);
+  }
+
+  template <typename Allocator, typename WriteHandler>
+  inline bool asio_handler_is_continuation(
+      write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
+  {
+    return asio_handler_cont_helpers::is_continuation(
+        this_handler->handler_);
+  }
+
+  template <typename Function, typename Allocator, typename WriteHandler>
+  inline void asio_handler_invoke(Function& function,
+      write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Function, typename Allocator, typename WriteHandler>
+  inline void asio_handler_invoke(const Function& function,
+      write_at_streambuf_op<Allocator, WriteHandler>* this_handler)
+  {
+    asio_handler_invoke_helpers::invoke(
+        function, this_handler->handler_);
+  }
+
+  template <typename Allocator, typename WriteHandler>
+  inline write_at_streambuf_op<Allocator, WriteHandler>
+  make_write_at_streambuf_op(
+      asio::basic_streambuf<Allocator>& b, WriteHandler handler)
+  {
+    return write_at_streambuf_op<Allocator, WriteHandler>(b, handler);
+  }
+} // namespace detail
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename Allocator, typename WriteHandler, typename Allocator1>
+struct associated_allocator<
+    detail::write_at_streambuf_op<Allocator, WriteHandler>,
+    Allocator1>
+{
+  typedef typename associated_allocator<WriteHandler, Allocator1>::type type;
+
+  static type get(
+      const detail::write_at_streambuf_op<Allocator, WriteHandler>& h,
+      const Allocator1& a = Allocator1()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<WriteHandler, Allocator1>::get(h.handler_, a);
+  }
+};
+
+template <typename Executor, typename WriteHandler, typename Executor1>
+struct associated_executor<
+    detail::write_at_streambuf_op<Executor, WriteHandler>,
+    Executor1>
+{
+  typedef typename associated_executor<WriteHandler, Executor1>::type type;
+
+  static type get(
+      const detail::write_at_streambuf_op<Executor, WriteHandler>& h,
+      const Executor1& ex = Executor1()) ASIO_NOEXCEPT
+  {
+    return associated_executor<WriteHandler, Executor1>::get(h.handler_, ex);
+  }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+template <typename AsyncRandomAccessWriteDevice, typename Allocator,
+    typename CompletionCondition, typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  async_write_at(d, offset, b.data(), completion_condition,
+    detail::write_at_streambuf_op<Allocator, ASIO_HANDLER_TYPE(
+      WriteHandler, void (asio::error_code, std::size_t))>(
+        b, init.completion_handler));
+
+  return init.result.get();
+}
+
+template <typename AsyncRandomAccessWriteDevice, typename Allocator,
+    typename WriteHandler>
+inline ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d,
+    uint64_t offset, asio::basic_streambuf<Allocator>& b,
+    ASIO_MOVE_ARG(WriteHandler) handler)
+{
+  // If you get an error on the following line it means that your handler does
+  // not meet the documented type requirements for a WriteHandler.
+  ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+  async_completion<WriteHandler,
+    void (asio::error_code, std::size_t)> init(handler);
+
+  async_write_at(d, offset, b.data(), transfer_all(),
+    detail::write_at_streambuf_op<Allocator, ASIO_HANDLER_TYPE(
+      WriteHandler, void (asio::error_code, std::size_t))>(
+        b, init.completion_handler));
+
+  return init.result.get();
+}
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_WRITE_AT_HPP
diff --git a/subprojects/asio/include/asio/io_context.hpp b/subprojects/asio/include/asio/io_context.hpp
new file mode 100644
index 000000000..4d93be44b
--- /dev/null
+++ b/subprojects/asio/include/asio/io_context.hpp
@@ -0,0 +1,876 @@
+//
+// io_context.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IO_CONTEXT_HPP
+#define ASIO_IO_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <stdexcept>
+#include <typeinfo>
+#include "asio/async_result.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/wrapped_handler.hpp"
+#include "asio/error_code.hpp"
+#include "asio/execution_context.hpp"
+
+#if defined(ASIO_HAS_CHRONO)
+# include "asio/detail/chrono.hpp"
+#endif // defined(ASIO_HAS_CHRONO)
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# include "asio/detail/winsock_init.hpp"
+#elif defined(__sun) || defined(__QNX__) || defined(__hpux) || defined(_AIX) \
+  || defined(__osf__)
+# include "asio/detail/signal_init.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail {
+#if defined(ASIO_HAS_IOCP)
+  typedef class win_iocp_io_context io_context_impl;
+  class win_iocp_overlapped_ptr;
+#else
+  typedef class scheduler io_context_impl;
+#endif
+} // namespace detail
+
+/// Provides core I/O functionality.
+/**
+ * The io_context class provides the core I/O functionality for users of the
+ * asynchronous I/O objects, including:
+ *
+ * @li asio::ip::tcp::socket
+ * @li asio::ip::tcp::acceptor
+ * @li asio::ip::udp::socket
+ * @li asio::deadline_timer.
+ *
+ * The io_context class also includes facilities intended for developers of
+ * custom asynchronous services.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe, with the specific exceptions of the restart()
+ * and notify_fork() functions. Calling restart() while there are unfinished
+ * run(), run_one(), run_for(), run_until(), poll() or poll_one() calls results
+ * in undefined behaviour. The notify_fork() function should not be called
+ * while any io_context function, or any function on an I/O object that is
+ * associated with the io_context, is being called in another thread.
+ *
+ * @par Concepts:
+ * Dispatcher.
+ *
+ * @par Synchronous and asynchronous operations
+ *
+ * Synchronous operations on I/O objects implicitly run the io_context object
+ * for an individual operation. The io_context functions run(), run_one(),
+ * run_for(), run_until(), poll() or poll_one() must be called for the
+ * io_context to perform asynchronous operations on behalf of a C++ program.
+ * Notification that an asynchronous operation has completed is delivered by
+ * invocation of the associated handler. Handlers are invoked only by a thread
+ * that is currently calling any overload of run(), run_one(), run_for(),
+ * run_until(), poll() or poll_one() for the io_context.
+ *
+ * @par Effect of exceptions thrown from handlers
+ *
+ * If an exception is thrown from a handler, the exception is allowed to
+ * propagate through the throwing thread's invocation of run(), run_one(),
+ * run_for(), run_until(), poll() or poll_one(). No other threads that are
+ * calling any of these functions are affected. It is then the responsibility
+ * of the application to catch the exception.
+ *
+ * After the exception has been caught, the run(), run_one(), run_for(),
+ * run_until(), poll() or poll_one() call may be restarted @em without the need
+ * for an intervening call to restart(). This allows the thread to rejoin the
+ * io_context object's thread pool without impacting any other threads in the
+ * pool.
+ *
+ * For example:
+ *
+ * @code
+ * asio::io_context io_context;
+ * ...
+ * for (;;)
+ * {
+ *   try
+ *   {
+ *     io_context.run();
+ *     break; // run() exited normally
+ *   }
+ *   catch (my_exception& e)
+ *   {
+ *     // Deal with exception as appropriate.
+ *   }
+ * }
+ * @endcode
+ *
+ * @par Submitting arbitrary tasks to the io_context
+ *
+ * To submit functions to the io_context, use the @ref asio::dispatch,
+ * @ref asio::post or @ref asio::defer free functions.
+ *
+ * For example:
+ *
+ * @code void my_task()
+ * {
+ *   ...
+ * }
+ *
+ * ...
+ *
+ * asio::io_context io_context;
+ *
+ * // Submit a function to the io_context.
+ * asio::post(io_context, my_task);
+ *
+ * // Submit a lambda object to the io_context.
+ * asio::post(io_context,
+ *     []()
+ *     {
+ *       ...
+ *     });
+ *
+ * // Run the io_context until it runs out of work.
+ * io_context.run(); @endcode
+ *
+ * @par Stopping the io_context from running out of work
+ *
+ * Some applications may need to prevent an io_context object's run() call from
+ * returning when there is no more work to do. For example, the io_context may
+ * be being run in a background thread that is launched prior to the
+ * application's asynchronous operations. The run() call may be kept running by
+ * creating an object of type
+ * asio::executor_work_guard<io_context::executor_type>:
+ *
+ * @code asio::io_context io_context;
+ * asio::executor_work_guard<asio::io_context::executor_type>
+ *   = asio::make_work_guard(io_context);
+ * ... @endcode
+ *
+ * To effect a shutdown, the application will then need to call the io_context
+ * object's stop() member function. This will cause the io_context run() call
+ * to return as soon as possible, abandoning unfinished operations and without
+ * permitting ready handlers to be dispatched.
+ *
+ * Alternatively, if the application requires that all operations and handlers
+ * be allowed to finish normally, the work object may be explicitly reset.
+ *
+ * @code asio::io_context io_context;
+ * asio::executor_work_guard<asio::io_context::executor_type>
+ *   = asio::make_work_guard(io_context);
+ * ...
+ * work.reset(); // Allow run() to exit. @endcode
+ */
+class io_context
+  : public execution_context
+{
+private:
+  typedef detail::io_context_impl impl_type;
+#if defined(ASIO_HAS_IOCP)
+  friend class detail::win_iocp_overlapped_ptr;
+#endif
+
+public:
+  class executor_type;
+  friend class executor_type;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  class work;
+  friend class work;
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  class service;
+
+#if !defined(ASIO_NO_EXTENSIONS)
+  class strand;
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+  /// The type used to count the number of handlers executed by the context.
+  typedef std::size_t count_type;
+
+  /// Constructor.
+  ASIO_DECL io_context();
+
+  /// Constructor.
+  /**
+   * Construct with a hint about the required level of concurrency.
+   *
+   * @param concurrency_hint A suggestion to the implementation on how many
+   * threads it should allow to run simultaneously.
+   */
+  ASIO_DECL explicit io_context(int concurrency_hint);
+
+  /// Destructor.
+  /**
+   * On destruction, the io_context performs the following sequence of
+   * operations:
+   *
+   * @li For each service object @c svc in the io_context set, in reverse order
+   * of the beginning of service object lifetime, performs
+   * @c svc->shutdown().
+   *
+   * @li Uninvoked handler objects that were scheduled for deferred invocation
+   * on the io_context, or any associated strand, are destroyed.
+   *
+   * @li For each service object @c svc in the io_context set, in reverse order
+   * of the beginning of service object lifetime, performs
+   * <tt>delete static_cast<io_context::service*>(svc)</tt>.
+   *
+   * @note The destruction sequence described above permits programs to
+   * simplify their resource management by using @c shared_ptr<>. Where an
+   * object's lifetime is tied to the lifetime of a connection (or some other
+   * sequence of asynchronous operations), a @c shared_ptr to the object would
+   * be bound into the handlers for all asynchronous operations associated with
+   * it. This works as follows:
+   *
+   * @li When a single connection ends, all associated asynchronous operations
+   * complete. The corresponding handler objects are destroyed, and all
+   * @c shared_ptr references to the objects are destroyed.
+   *
+   * @li To shut down the whole program, the io_context function stop() is
+   * called to terminate any run() calls as soon as possible. The io_context
+   * destructor defined above destroys all handlers, causing all @c shared_ptr
+   * references to all connection objects to be destroyed.
+   */
+  ASIO_DECL ~io_context();
+
+  /// Obtains the executor associated with the io_context.
+  executor_type get_executor() ASIO_NOEXCEPT;
+
+  /// Run the io_context object's event processing loop.
+  /**
+   * The run() function blocks until all work has finished and there are no
+   * more handlers to be dispatched, or until the io_context has been stopped.
+   *
+   * Multiple threads may call the run() function to set up a pool of threads
+   * from which the io_context may execute handlers. All threads that are
+   * waiting in the pool are equivalent and the io_context may choose any one
+   * of them to invoke a handler.
+   *
+   * A normal exit from the run() function implies that the io_context object
+   * is stopped (the stopped() function returns @c true). Subsequent calls to
+   * run(), run_one(), poll() or poll_one() will return immediately unless there
+   * is a prior call to restart().
+   *
+   * @return The number of handlers that were executed.
+   *
+   * @note Calling the run() function from a thread that is currently calling
+   * one of run(), run_one(), run_for(), run_until(), poll() or poll_one() on
+   * the same io_context object may introduce the potential for deadlock. It is
+   * the caller's reponsibility to avoid this.
+   *
+   * The poll() function may also be used to dispatch ready handlers, but
+   * without blocking.
+   */
+  ASIO_DECL count_type run();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use non-error_code overload.) Run the io_context object's
+  /// event processing loop.
+  /**
+   * The run() function blocks until all work has finished and there are no
+   * more handlers to be dispatched, or until the io_context has been stopped.
+   *
+   * Multiple threads may call the run() function to set up a pool of threads
+   * from which the io_context may execute handlers. All threads that are
+   * waiting in the pool are equivalent and the io_context may choose any one
+   * of them to invoke a handler.
+   *
+   * A normal exit from the run() function implies that the io_context object
+   * is stopped (the stopped() function returns @c true). Subsequent calls to
+   * run(), run_one(), poll() or poll_one() will return immediately unless there
+   * is a prior call to restart().
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of handlers that were executed.
+   *
+   * @note Calling the run() function from a thread that is currently calling
+   * one of run(), run_one(), run_for(), run_until(), poll() or poll_one() on
+   * the same io_context object may introduce the potential for deadlock. It is
+   * the caller's reponsibility to avoid this.
+   *
+   * The poll() function may also be used to dispatch ready handlers, but
+   * without blocking.
+   */
+  ASIO_DECL count_type run(asio::error_code& ec);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+#if defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+  /// Run the io_context object's event processing loop for a specified
+  /// duration.
+  /**
+   * The run_for() function blocks until all work has finished and there are no
+   * more handlers to be dispatched, until the io_context has been stopped, or
+   * until the specified duration has elapsed.
+   *
+   * @param rel_time The duration for which the call may block.
+   *
+   * @return The number of handlers that were executed.
+   */
+  template <typename Rep, typename Period>
+  std::size_t run_for(const chrono::duration<Rep, Period>& rel_time);
+
+  /// Run the io_context object's event processing loop until a specified time.
+  /**
+   * The run_until() function blocks until all work has finished and there are
+   * no more handlers to be dispatched, until the io_context has been stopped,
+   * or until the specified time has been reached.
+   *
+   * @param abs_time The time point until which the call may block.
+   *
+   * @return The number of handlers that were executed.
+   */
+  template <typename Clock, typename Duration>
+  std::size_t run_until(const chrono::time_point<Clock, Duration>& abs_time);
+#endif // defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+  /// Run the io_context object's event processing loop to execute at most one
+  /// handler.
+  /**
+   * The run_one() function blocks until one handler has been dispatched, or
+   * until the io_context has been stopped.
+   *
+   * @return The number of handlers that were executed. A zero return value
+   * implies that the io_context object is stopped (the stopped() function
+   * returns @c true). Subsequent calls to run(), run_one(), poll() or
+   * poll_one() will return immediately unless there is a prior call to
+   * restart().
+   *
+   * @note Calling the run_one() function from a thread that is currently
+   * calling one of run(), run_one(), run_for(), run_until(), poll() or
+   * poll_one() on the same io_context object may introduce the potential for
+   * deadlock. It is the caller's reponsibility to avoid this.
+   */
+  ASIO_DECL count_type run_one();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use non-error_code overlaod.) Run the io_context object's
+  /// event processing loop to execute at most one handler.
+  /**
+   * The run_one() function blocks until one handler has been dispatched, or
+   * until the io_context has been stopped.
+   *
+   * @return The number of handlers that were executed. A zero return value
+   * implies that the io_context object is stopped (the stopped() function
+   * returns @c true). Subsequent calls to run(), run_one(), poll() or
+   * poll_one() will return immediately unless there is a prior call to
+   * restart().
+   *
+   * @return The number of handlers that were executed.
+   *
+   * @note Calling the run_one() function from a thread that is currently
+   * calling one of run(), run_one(), run_for(), run_until(), poll() or
+   * poll_one() on the same io_context object may introduce the potential for
+   * deadlock. It is the caller's reponsibility to avoid this.
+   */
+  ASIO_DECL count_type run_one(asio::error_code& ec);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+#if defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+  /// Run the io_context object's event processing loop for a specified duration
+  /// to execute at most one handler.
+  /**
+   * The run_one_for() function blocks until one handler has been dispatched,
+   * until the io_context has been stopped, or until the specified duration has
+   * elapsed.
+   *
+   * @param rel_time The duration for which the call may block.
+   *
+   * @return The number of handlers that were executed.
+   */
+  template <typename Rep, typename Period>
+  std::size_t run_one_for(const chrono::duration<Rep, Period>& rel_time);
+
+  /// Run the io_context object's event processing loop until a specified time
+  /// to execute at most one handler.
+  /**
+   * The run_one_until() function blocks until one handler has been dispatched,
+   * until the io_context has been stopped, or until the specified time has
+   * been reached.
+   *
+   * @param abs_time The time point until which the call may block.
+   *
+   * @return The number of handlers that were executed.
+   */
+  template <typename Clock, typename Duration>
+  std::size_t run_one_until(
+      const chrono::time_point<Clock, Duration>& abs_time);
+#endif // defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+  /// Run the io_context object's event processing loop to execute ready
+  /// handlers.
+  /**
+   * The poll() function runs handlers that are ready to run, without blocking,
+   * until the io_context has been stopped or there are no more ready handlers.
+   *
+   * @return The number of handlers that were executed.
+   */
+  ASIO_DECL count_type poll();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use non-error_code overload.) Run the io_context object's
+  /// event processing loop to execute ready handlers.
+  /**
+   * The poll() function runs handlers that are ready to run, without blocking,
+   * until the io_context has been stopped or there are no more ready handlers.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of handlers that were executed.
+   */
+  ASIO_DECL count_type poll(asio::error_code& ec);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Run the io_context object's event processing loop to execute one ready
+  /// handler.
+  /**
+   * The poll_one() function runs at most one handler that is ready to run,
+   * without blocking.
+   *
+   * @return The number of handlers that were executed.
+   */
+  ASIO_DECL count_type poll_one();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use non-error_code overload.) Run the io_context object's
+  /// event processing loop to execute one ready handler.
+  /**
+   * The poll_one() function runs at most one handler that is ready to run,
+   * without blocking.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @return The number of handlers that were executed.
+   */
+  ASIO_DECL count_type poll_one(asio::error_code& ec);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Stop the io_context object's event processing loop.
+  /**
+   * This function does not block, but instead simply signals the io_context to
+   * stop. All invocations of its run() or run_one() member functions should
+   * return as soon as possible. Subsequent calls to run(), run_one(), poll()
+   * or poll_one() will return immediately until restart() is called.
+   */
+  ASIO_DECL void stop();
+
+  /// Determine whether the io_context object has been stopped.
+  /**
+   * This function is used to determine whether an io_context object has been
+   * stopped, either through an explicit call to stop(), or due to running out
+   * of work. When an io_context object is stopped, calls to run(), run_one(),
+   * poll() or poll_one() will return immediately without invoking any
+   * handlers.
+   *
+   * @return @c true if the io_context object is stopped, otherwise @c false.
+   */
+  ASIO_DECL bool stopped() const;
+
+  /// Restart the io_context in preparation for a subsequent run() invocation.
+  /**
+   * This function must be called prior to any second or later set of
+   * invocations of the run(), run_one(), poll() or poll_one() functions when a
+   * previous invocation of these functions returned due to the io_context
+   * being stopped or running out of work. After a call to restart(), the
+   * io_context object's stopped() function will return @c false.
+   *
+   * This function must not be called while there are any unfinished calls to
+   * the run(), run_one(), poll() or poll_one() functions.
+   */
+  ASIO_DECL void restart();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use restart().) Reset the io_context in preparation for a
+  /// subsequent run() invocation.
+  /**
+   * This function must be called prior to any second or later set of
+   * invocations of the run(), run_one(), poll() or poll_one() functions when a
+   * previous invocation of these functions returned due to the io_context
+   * being stopped or running out of work. After a call to restart(), the
+   * io_context object's stopped() function will return @c false.
+   *
+   * This function must not be called while there are any unfinished calls to
+   * the run(), run_one(), poll() or poll_one() functions.
+   */
+  void reset();
+
+  /// (Deprecated: Use asio::dispatch().) Request the io_context to
+  /// invoke the given handler.
+  /**
+   * This function is used to ask the io_context to execute the given handler.
+   *
+   * The io_context guarantees that the handler will only be called in a thread
+   * in which the run(), run_one(), poll() or poll_one() member functions is
+   * currently being invoked. The handler may be executed inside this function
+   * if the guarantee can be met.
+   *
+   * @param handler The handler to be called. The io_context will make
+   * a copy of the handler object as required. The function signature of the
+   * handler must be: @code void handler(); @endcode
+   *
+   * @note This function throws an exception only if:
+   *
+   * @li the handler's @c asio_handler_allocate function; or
+   *
+   * @li the handler's copy constructor
+   *
+   * throws an exception.
+   */
+  template <typename LegacyCompletionHandler>
+  ASIO_INITFN_RESULT_TYPE(LegacyCompletionHandler, void ())
+  dispatch(ASIO_MOVE_ARG(LegacyCompletionHandler) handler);
+
+  /// (Deprecated: Use asio::post().) Request the io_context to invoke
+  /// the given handler and return immediately.
+  /**
+   * This function is used to ask the io_context to execute the given handler,
+   * but without allowing the io_context to call the handler from inside this
+   * function.
+   *
+   * The io_context guarantees that the handler will only be called in a thread
+   * in which the run(), run_one(), poll() or poll_one() member functions is
+   * currently being invoked.
+   *
+   * @param handler The handler to be called. The io_context will make
+   * a copy of the handler object as required. The function signature of the
+   * handler must be: @code void handler(); @endcode
+   *
+   * @note This function throws an exception only if:
+   *
+   * @li the handler's @c asio_handler_allocate function; or
+   *
+   * @li the handler's copy constructor
+   *
+   * throws an exception.
+   */
+  template <typename LegacyCompletionHandler>
+  ASIO_INITFN_RESULT_TYPE(LegacyCompletionHandler, void ())
+  post(ASIO_MOVE_ARG(LegacyCompletionHandler) handler);
+
+  /// (Deprecated: Use asio::bind_executor().) Create a new handler that
+  /// automatically dispatches the wrapped handler on the io_context.
+  /**
+   * This function is used to create a new handler function object that, when
+   * invoked, will automatically pass the wrapped handler to the io_context
+   * object's dispatch function.
+   *
+   * @param handler The handler to be wrapped. The io_context will make a copy
+   * of the handler object as required. The function signature of the handler
+   * must be: @code void handler(A1 a1, ... An an); @endcode
+   *
+   * @return A function object that, when invoked, passes the wrapped handler to
+   * the io_context object's dispatch function. Given a function object with the
+   * signature:
+   * @code R f(A1 a1, ... An an); @endcode
+   * If this function object is passed to the wrap function like so:
+   * @code io_context.wrap(f); @endcode
+   * then the return value is a function object with the signature
+   * @code void g(A1 a1, ... An an); @endcode
+   * that, when invoked, executes code equivalent to:
+   * @code io_context.dispatch(boost::bind(f, a1, ... an)); @endcode
+   */
+  template <typename Handler>
+#if defined(GENERATING_DOCUMENTATION)
+  unspecified
+#else
+  detail::wrapped_handler<io_context&, Handler>
+#endif
+  wrap(Handler handler);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+private:
+  // Helper function to add the implementation.
+  ASIO_DECL impl_type& add_impl(impl_type* impl);
+
+  // Backwards compatible overload for use with services derived from
+  // io_context::service.
+  template <typename Service>
+  friend Service& use_service(io_context& ioc);
+
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  detail::winsock_init<> init_;
+#elif defined(__sun) || defined(__QNX__) || defined(__hpux) || defined(_AIX) \
+  || defined(__osf__)
+  detail::signal_init<> init_;
+#endif
+
+  // The implementation.
+  impl_type& impl_;
+};
+
+/// Executor used to submit functions to an io_context.
+class io_context::executor_type
+{
+public:
+  /// Obtain the underlying execution context.
+  io_context& context() const ASIO_NOEXCEPT;
+
+  /// Inform the io_context that it has some outstanding work to do.
+  /**
+   * This function is used to inform the io_context that some work has begun.
+   * This ensures that the io_context's run() and run_one() functions do not
+   * exit while the work is underway.
+   */
+  void on_work_started() const ASIO_NOEXCEPT;
+
+  /// Inform the io_context that some work is no longer outstanding.
+  /**
+   * This function is used to inform the io_context that some work has
+   * finished. Once the count of unfinished work reaches zero, the io_context
+   * is stopped and the run() and run_one() functions may exit.
+   */
+  void on_work_finished() const ASIO_NOEXCEPT;
+
+  /// Request the io_context to invoke the given function object.
+  /**
+   * This function is used to ask the io_context to execute the given function
+   * object. If the current thread is running the io_context, @c dispatch()
+   * executes the function before returning. Otherwise, the function will be
+   * scheduled to run on the io_context.
+   *
+   * @param f The function object to be called. The executor will make a copy
+   * of the handler object as required. The function signature of the function
+   * object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the io_context to invoke the given function object.
+  /**
+   * This function is used to ask the io_context to execute the given function
+   * object. The function object will never be executed inside @c post().
+   * Instead, it will be scheduled to run on the io_context.
+   *
+   * @param f The function object to be called. The executor will make a copy
+   * of the handler object as required. The function signature of the function
+   * object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the io_context to invoke the given function object.
+  /**
+   * This function is used to ask the io_context to execute the given function
+   * object. The function object will never be executed inside @c defer().
+   * Instead, it will be scheduled to run on the io_context.
+   *
+   * If the current thread belongs to the io_context, @c defer() will delay
+   * scheduling the function object until the current thread returns control to
+   * the pool.
+   *
+   * @param f The function object to be called. The executor will make a copy
+   * of the handler object as required. The function signature of the function
+   * object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Determine whether the io_context is running in the current thread.
+  /**
+   * @return @c true if the current thread is running the io_context. Otherwise
+   * returns @c false.
+   */
+  bool running_in_this_thread() const ASIO_NOEXCEPT;
+
+  /// Compare two executors for equality.
+  /**
+   * Two executors are equal if they refer to the same underlying io_context.
+   */
+  friend bool operator==(const executor_type& a,
+      const executor_type& b) ASIO_NOEXCEPT
+  {
+    return &a.io_context_ == &b.io_context_;
+  }
+
+  /// Compare two executors for inequality.
+  /**
+   * Two executors are equal if they refer to the same underlying io_context.
+   */
+  friend bool operator!=(const executor_type& a,
+      const executor_type& b) ASIO_NOEXCEPT
+  {
+    return &a.io_context_ != &b.io_context_;
+  }
+
+private:
+  friend class io_context;
+
+  // Constructor.
+  explicit executor_type(io_context& i) : io_context_(i) {}
+
+  // The underlying io_context.
+  io_context& io_context_;
+};
+
+#if !defined(ASIO_NO_DEPRECATED)
+/// (Deprecated: Use executor_work_guard.) Class to inform the io_context when
+/// it has work to do.
+/**
+ * The work class is used to inform the io_context when work starts and
+ * finishes. This ensures that the io_context object's run() function will not
+ * exit while work is underway, and that it does exit when there is no
+ * unfinished work remaining.
+ *
+ * The work class is copy-constructible so that it may be used as a data member
+ * in a handler class. It is not assignable.
+ */
+class io_context::work
+{
+public:
+  /// Constructor notifies the io_context that work is starting.
+  /**
+   * The constructor is used to inform the io_context that some work has begun.
+   * This ensures that the io_context object's run() function will not exit
+   * while the work is underway.
+   */
+  explicit work(asio::io_context& io_context);
+
+  /// Copy constructor notifies the io_context that work is starting.
+  /**
+   * The constructor is used to inform the io_context that some work has begun.
+   * This ensures that the io_context object's run() function will not exit
+   * while the work is underway.
+   */
+  work(const work& other);
+
+  /// Destructor notifies the io_context that the work is complete.
+  /**
+   * The destructor is used to inform the io_context that some work has
+   * finished. Once the count of unfinished work reaches zero, the io_context
+   * object's run() function is permitted to exit.
+   */
+  ~work();
+
+  /// Get the io_context associated with the work.
+  asio::io_context& get_io_context();
+
+  /// (Deprecated: Use get_io_context().) Get the io_context associated with the
+  /// work.
+  asio::io_context& get_io_service();
+
+private:
+  // Prevent assignment.
+  void operator=(const work& other);
+
+  // The io_context implementation.
+  detail::io_context_impl& io_context_impl_;
+};
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+/// Base class for all io_context services.
+class io_context::service
+  : public execution_context::service
+{
+public:
+  /// Get the io_context object that owns the service.
+  asio::io_context& get_io_context();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// Get the io_context object that owns the service.
+  asio::io_context& get_io_service();
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+private:
+  /// Destroy all user-defined handler objects owned by the service.
+  ASIO_DECL virtual void shutdown();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use shutdown().) Destroy all user-defined handler objects
+  /// owned by the service.
+  ASIO_DECL virtual void shutdown_service();
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Handle notification of a fork-related event to perform any necessary
+  /// housekeeping.
+  /**
+   * This function is not a pure virtual so that services only have to
+   * implement it if necessary. The default implementation does nothing.
+   */
+  ASIO_DECL virtual void notify_fork(
+      execution_context::fork_event event);
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use notify_fork().) Handle notification of a fork-related
+  /// event to perform any necessary housekeeping.
+  /**
+   * This function is not a pure virtual so that services only have to
+   * implement it if necessary. The default implementation does nothing.
+   */
+  ASIO_DECL virtual void fork_service(
+      execution_context::fork_event event);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+protected:
+  /// Constructor.
+  /**
+   * @param owner The io_context object that owns the service.
+   */
+  ASIO_DECL service(asio::io_context& owner);
+
+  /// Destructor.
+  ASIO_DECL virtual ~service();
+};
+
+namespace detail {
+
+// Special service base class to keep classes header-file only.
+template <typename Type>
+class service_base
+  : public asio::io_context::service
+{
+public:
+  static asio::detail::service_id<Type> id;
+
+  // Constructor.
+  service_base(asio::io_context& io_context)
+    : asio::io_context::service(io_context)
+  {
+  }
+};
+
+template <typename Type>
+asio::detail::service_id<Type> service_base<Type>::id;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/io_context.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/io_context.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+// If both io_context.hpp and strand.hpp have been included, automatically
+// include the header file needed for the io_context::strand class.
+#if !defined(ASIO_NO_EXTENSIONS)
+# if defined(ASIO_STRAND_HPP)
+#  include "asio/io_context_strand.hpp"
+# endif // defined(ASIO_STRAND_HPP)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#endif // ASIO_IO_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/io_context_strand.hpp b/subprojects/asio/include/asio/io_context_strand.hpp
new file mode 100644
index 000000000..3c596f125
--- /dev/null
+++ b/subprojects/asio/include/asio/io_context_strand.hpp
@@ -0,0 +1,384 @@
+//
+// io_context_strand.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IO_CONTEXT_STRAND_HPP
+#define ASIO_IO_CONTEXT_STRAND_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_NO_EXTENSIONS)
+
+#include "asio/async_result.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/strand_service.hpp"
+#include "asio/detail/wrapped_handler.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides serialised handler execution.
+/**
+ * The io_context::strand class provides the ability to post and dispatch
+ * handlers with the guarantee that none of those handlers will execute
+ * concurrently.
+ *
+ * @par Order of handler invocation
+ * Given:
+ *
+ * @li a strand object @c s
+ *
+ * @li an object @c a meeting completion handler requirements
+ *
+ * @li an object @c a1 which is an arbitrary copy of @c a made by the
+ * implementation
+ *
+ * @li an object @c b meeting completion handler requirements
+ *
+ * @li an object @c b1 which is an arbitrary copy of @c b made by the
+ * implementation
+ *
+ * if any of the following conditions are true:
+ *
+ * @li @c s.post(a) happens-before @c s.post(b)
+ * 
+ * @li @c s.post(a) happens-before @c s.dispatch(b), where the latter is
+ * performed outside the strand
+ * 
+ * @li @c s.dispatch(a) happens-before @c s.post(b), where the former is
+ * performed outside the strand
+ * 
+ * @li @c s.dispatch(a) happens-before @c s.dispatch(b), where both are
+ * performed outside the strand
+ *   
+ * then @c asio_handler_invoke(a1, &a1) happens-before
+ * @c asio_handler_invoke(b1, &b1).
+ * 
+ * Note that in the following case:
+ * @code async_op_1(..., s.wrap(a));
+ * async_op_2(..., s.wrap(b)); @endcode
+ * the completion of the first async operation will perform @c s.dispatch(a),
+ * and the second will perform @c s.dispatch(b), but the order in which those
+ * are performed is unspecified. That is, you cannot state whether one
+ * happens-before the other. Therefore none of the above conditions are met and
+ * no ordering guarantee is made.
+ *
+ * @note The implementation makes no guarantee that handlers posted or
+ * dispatched through different @c strand objects will be invoked concurrently.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Dispatcher.
+ */
+class io_context::strand
+{
+public:
+  /// Constructor.
+  /**
+   * Constructs the strand.
+   *
+   * @param io_context The io_context object that the strand will use to
+   * dispatch handlers that are ready to be run.
+   */
+  explicit strand(asio::io_context& io_context)
+    : service_(asio::use_service<
+        asio::detail::strand_service>(io_context))
+  {
+    service_.construct(impl_);
+  }
+
+  /// Destructor.
+  /**
+   * Destroys a strand.
+   *
+   * Handlers posted through the strand that have not yet been invoked will
+   * still be dispatched in a way that meets the guarantee of non-concurrency.
+   */
+  ~strand()
+  {
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use context().) Get the io_context associated with the
+  /// strand.
+  /**
+   * This function may be used to obtain the io_context object that the strand
+   * uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the strand will use to
+   * dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return service_.get_io_context();
+  }
+
+  /// (Deprecated: Use context().) Get the io_context associated with the
+  /// strand.
+  /**
+   * This function may be used to obtain the io_context object that the strand
+   * uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the strand will use to
+   * dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return service_.get_io_context();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Obtain the underlying execution context.
+  asio::io_context& context() const ASIO_NOEXCEPT
+  {
+    return service_.get_io_context();
+  }
+
+  /// Inform the strand that it has some outstanding work to do.
+  /**
+   * The strand delegates this call to its underlying io_context.
+   */
+  void on_work_started() const ASIO_NOEXCEPT
+  {
+    context().get_executor().on_work_started();
+  }
+
+  /// Inform the strand that some work is no longer outstanding.
+  /**
+   * The strand delegates this call to its underlying io_context.
+   */
+  void on_work_finished() const ASIO_NOEXCEPT
+  {
+    context().get_executor().on_work_finished();
+  }
+
+  /// Request the strand to invoke the given function object.
+  /**
+   * This function is used to ask the strand to execute the given function
+   * object on its underlying io_context. The function object will be executed
+   * inside this function if the strand is not otherwise busy and if the
+   * underlying io_context's executor's @c dispatch() function is also able to
+   * execute the function before returning.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+  {
+    typename decay<Function>::type tmp(ASIO_MOVE_CAST(Function)(f));
+    service_.dispatch(impl_, tmp);
+    (void)a;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use asio::dispatch().) Request the strand to invoke
+  /// the given handler.
+  /**
+   * This function is used to ask the strand to execute the given handler.
+   *
+   * The strand object guarantees that handlers posted or dispatched through
+   * the strand will not be executed concurrently. The handler may be executed
+   * inside this function if the guarantee can be met. If this function is
+   * called from within a handler that was posted or dispatched through the same
+   * strand, then the new handler will be executed immediately.
+   *
+   * The strand's guarantee is in addition to the guarantee provided by the
+   * underlying io_context. The io_context guarantees that the handler will only
+   * be called in a thread in which the io_context's run member function is
+   * currently being invoked.
+   *
+   * @param handler The handler to be called. The strand will make a copy of the
+   * handler object as required. The function signature of the handler must be:
+   * @code void handler(); @endcode
+   */
+  template <typename LegacyCompletionHandler>
+  ASIO_INITFN_RESULT_TYPE(LegacyCompletionHandler, void ())
+  dispatch(ASIO_MOVE_ARG(LegacyCompletionHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a LegacyCompletionHandler.
+    ASIO_LEGACY_COMPLETION_HANDLER_CHECK(
+        LegacyCompletionHandler, handler) type_check;
+
+    async_completion<LegacyCompletionHandler, void ()> init(handler);
+
+    service_.dispatch(impl_, init.completion_handler);
+
+    return init.result.get();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Request the strand to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object will never be executed inside this function.
+   * Instead, it will be scheduled to run by the underlying io_context.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+  {
+    typename decay<Function>::type tmp(ASIO_MOVE_CAST(Function)(f));
+    service_.post(impl_, tmp);
+    (void)a;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use asio::post().) Request the strand to invoke the
+  /// given handler and return immediately.
+  /**
+   * This function is used to ask the strand to execute the given handler, but
+   * without allowing the strand to call the handler from inside this function.
+   *
+   * The strand object guarantees that handlers posted or dispatched through
+   * the strand will not be executed concurrently. The strand's guarantee is in
+   * addition to the guarantee provided by the underlying io_context. The
+   * io_context guarantees that the handler will only be called in a thread in
+   * which the io_context's run member function is currently being invoked.
+   *
+   * @param handler The handler to be called. The strand will make a copy of the
+   * handler object as required. The function signature of the handler must be:
+   * @code void handler(); @endcode
+   */
+  template <typename LegacyCompletionHandler>
+  ASIO_INITFN_RESULT_TYPE(LegacyCompletionHandler, void ())
+  post(ASIO_MOVE_ARG(LegacyCompletionHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a LegacyCompletionHandler.
+    ASIO_LEGACY_COMPLETION_HANDLER_CHECK(
+        LegacyCompletionHandler, handler) type_check;
+
+    async_completion<LegacyCompletionHandler, void ()> init(handler);
+
+    service_.post(impl_, init.completion_handler);
+
+    return init.result.get();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Request the strand to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object will never be executed inside this function.
+   * Instead, it will be scheduled to run by the underlying io_context.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+  {
+    typename decay<Function>::type tmp(ASIO_MOVE_CAST(Function)(f));
+    service_.post(impl_, tmp);
+    (void)a;
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use asio::bind_executor().) Create a new handler that
+  /// automatically dispatches the wrapped handler on the strand.
+  /**
+   * This function is used to create a new handler function object that, when
+   * invoked, will automatically pass the wrapped handler to the strand's
+   * dispatch function.
+   *
+   * @param handler The handler to be wrapped. The strand will make a copy of
+   * the handler object as required. The function signature of the handler must
+   * be: @code void handler(A1 a1, ... An an); @endcode
+   *
+   * @return A function object that, when invoked, passes the wrapped handler to
+   * the strand's dispatch function. Given a function object with the signature:
+   * @code R f(A1 a1, ... An an); @endcode
+   * If this function object is passed to the wrap function like so:
+   * @code strand.wrap(f); @endcode
+   * then the return value is a function object with the signature
+   * @code void g(A1 a1, ... An an); @endcode
+   * that, when invoked, executes code equivalent to:
+   * @code strand.dispatch(boost::bind(f, a1, ... an)); @endcode
+   */
+  template <typename Handler>
+#if defined(GENERATING_DOCUMENTATION)
+  unspecified
+#else
+  detail::wrapped_handler<strand, Handler, detail::is_continuation_if_running>
+#endif
+  wrap(Handler handler)
+  {
+    return detail::wrapped_handler<io_context::strand, Handler,
+        detail::is_continuation_if_running>(*this, handler);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Determine whether the strand is running in the current thread.
+  /**
+   * @return @c true if the current thread is executing a handler that was
+   * submitted to the strand using post(), dispatch() or wrap(). Otherwise
+   * returns @c false.
+   */
+  bool running_in_this_thread() const ASIO_NOEXCEPT
+  {
+    return service_.running_in_this_thread(impl_);
+  }
+
+  /// Compare two strands for equality.
+  /**
+   * Two strands are equal if they refer to the same ordered, non-concurrent
+   * state.
+   */
+  friend bool operator==(const strand& a, const strand& b) ASIO_NOEXCEPT
+  {
+    return a.impl_ == b.impl_;
+  }
+
+  /// Compare two strands for inequality.
+  /**
+   * Two strands are equal if they refer to the same ordered, non-concurrent
+   * state.
+   */
+  friend bool operator!=(const strand& a, const strand& b) ASIO_NOEXCEPT
+  {
+    return a.impl_ != b.impl_;
+  }
+
+private:
+  asio::detail::strand_service& service_;
+  mutable asio::detail::strand_service::implementation_type impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#endif // ASIO_IO_CONTEXT_STRAND_HPP
diff --git a/subprojects/asio/include/asio/io_service.hpp b/subprojects/asio/include/asio/io_service.hpp
new file mode 100644
index 000000000..ed05c8341
--- /dev/null
+++ b/subprojects/asio/include/asio/io_service.hpp
@@ -0,0 +1,33 @@
+//
+// io_service.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IO_SERVICE_HPP
+#define ASIO_IO_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if !defined(ASIO_NO_DEPRECATED)
+/// Typedef for backwards compatibility.
+typedef io_context io_service;
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IO_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/io_service_strand.hpp b/subprojects/asio/include/asio/io_service_strand.hpp
new file mode 100644
index 000000000..7093f0e90
--- /dev/null
+++ b/subprojects/asio/include/asio/io_service_strand.hpp
@@ -0,0 +1,20 @@
+//
+// io_service_strand.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IO_SERVICE_STRAND_HPP
+#define ASIO_IO_SERVICE_STRAND_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/io_context_strand.hpp"
+
+#endif // ASIO_IO_SERVICE_STRAND_HPP
diff --git a/subprojects/asio/include/asio/ip/address.hpp b/subprojects/asio/include/asio/ip/address.hpp
new file mode 100644
index 000000000..cf852a6d6
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/address.hpp
@@ -0,0 +1,260 @@
+//
+// ip/address.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ADDRESS_HPP
+#define ASIO_IP_ADDRESS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/throw_exception.hpp"
+#include "asio/detail/string_view.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error_code.hpp"
+#include "asio/ip/address_v4.hpp"
+#include "asio/ip/address_v6.hpp"
+#include "asio/ip/bad_address_cast.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+# include <iosfwd>
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Implements version-independent IP addresses.
+/**
+ * The asio::ip::address class provides the ability to use either IP
+ * version 4 or version 6 addresses.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class address
+{
+public:
+  /// Default constructor.
+  ASIO_DECL address();
+
+  /// Construct an address from an IPv4 address.
+  ASIO_DECL address(const asio::ip::address_v4& ipv4_address);
+
+  /// Construct an address from an IPv6 address.
+  ASIO_DECL address(const asio::ip::address_v6& ipv6_address);
+
+  /// Copy constructor.
+  ASIO_DECL address(const address& other);
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  ASIO_DECL address(address&& other);
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from another address.
+  ASIO_DECL address& operator=(const address& other);
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move-assign from another address.
+  ASIO_DECL address& operator=(address&& other);
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from an IPv4 address.
+  ASIO_DECL address& operator=(
+      const asio::ip::address_v4& ipv4_address);
+
+  /// Assign from an IPv6 address.
+  ASIO_DECL address& operator=(
+      const asio::ip::address_v6& ipv6_address);
+
+  /// Get whether the address is an IP version 4 address.
+  bool is_v4() const
+  {
+    return type_ == ipv4;
+  }
+
+  /// Get whether the address is an IP version 6 address.
+  bool is_v6() const
+  {
+    return type_ == ipv6;
+  }
+
+  /// Get the address as an IP version 4 address.
+  ASIO_DECL asio::ip::address_v4 to_v4() const;
+
+  /// Get the address as an IP version 6 address.
+  ASIO_DECL asio::ip::address_v6 to_v6() const;
+
+  /// Get the address as a string.
+  ASIO_DECL std::string to_string() const;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use other overload.) Get the address as a string.
+  ASIO_DECL std::string to_string(asio::error_code& ec) const;
+
+  /// (Deprecated: Use make_address().) Create an address from an IPv4 address
+  /// string in dotted decimal form, or from an IPv6 address in hexadecimal
+  /// notation.
+  static address from_string(const char* str);
+
+  /// (Deprecated: Use make_address().) Create an address from an IPv4 address
+  /// string in dotted decimal form, or from an IPv6 address in hexadecimal
+  /// notation.
+  static address from_string(const char* str, asio::error_code& ec);
+
+  /// (Deprecated: Use make_address().) Create an address from an IPv4 address
+  /// string in dotted decimal form, or from an IPv6 address in hexadecimal
+  /// notation.
+  static address from_string(const std::string& str);
+
+  /// (Deprecated: Use make_address().) Create an address from an IPv4 address
+  /// string in dotted decimal form, or from an IPv6 address in hexadecimal
+  /// notation.
+  static address from_string(
+      const std::string& str, asio::error_code& ec);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Determine whether the address is a loopback address.
+  ASIO_DECL bool is_loopback() const;
+
+  /// Determine whether the address is unspecified.
+  ASIO_DECL bool is_unspecified() const;
+
+  /// Determine whether the address is a multicast address.
+  ASIO_DECL bool is_multicast() const;
+
+  /// Compare two addresses for equality.
+  ASIO_DECL friend bool operator==(const address& a1, const address& a2);
+
+  /// Compare two addresses for inequality.
+  friend bool operator!=(const address& a1, const address& a2)
+  {
+    return !(a1 == a2);
+  }
+
+  /// Compare addresses for ordering.
+  ASIO_DECL friend bool operator<(const address& a1, const address& a2);
+
+  /// Compare addresses for ordering.
+  friend bool operator>(const address& a1, const address& a2)
+  {
+    return a2 < a1;
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator<=(const address& a1, const address& a2)
+  {
+    return !(a2 < a1);
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator>=(const address& a1, const address& a2)
+  {
+    return !(a1 < a2);
+  }
+
+private:
+  // The type of the address.
+  enum { ipv4, ipv6 } type_;
+
+  // The underlying IPv4 address.
+  asio::ip::address_v4 ipv4_address_;
+
+  // The underlying IPv6 address.
+  asio::ip::address_v6 ipv6_address_;
+};
+
+/// Create an address from an IPv4 address string in dotted decimal form,
+/// or from an IPv6 address in hexadecimal notation.
+/**
+ * @relates address
+ */
+ASIO_DECL address make_address(const char* str);
+
+/// Create an address from an IPv4 address string in dotted decimal form,
+/// or from an IPv6 address in hexadecimal notation.
+/**
+ * @relates address
+ */
+ASIO_DECL address make_address(
+    const char* str, asio::error_code& ec);
+
+/// Create an address from an IPv4 address string in dotted decimal form,
+/// or from an IPv6 address in hexadecimal notation.
+/**
+ * @relates address
+ */
+ASIO_DECL address make_address(const std::string& str);
+
+/// Create an address from an IPv4 address string in dotted decimal form,
+/// or from an IPv6 address in hexadecimal notation.
+/**
+ * @relates address
+ */
+ASIO_DECL address make_address(
+    const std::string& str, asio::error_code& ec);
+
+#if defined(ASIO_HAS_STRING_VIEW) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Create an address from an IPv4 address string in dotted decimal form,
+/// or from an IPv6 address in hexadecimal notation.
+/**
+ * @relates address
+ */
+ASIO_DECL address make_address(string_view str);
+
+/// Create an address from an IPv4 address string in dotted decimal form,
+/// or from an IPv6 address in hexadecimal notation.
+/**
+ * @relates address
+ */
+ASIO_DECL address make_address(
+    string_view str, asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Output an address as a string.
+/**
+ * Used to output a human-readable string for a specified address.
+ *
+ * @param os The output stream to which the string will be written.
+ *
+ * @param addr The address to be written.
+ *
+ * @return The output stream.
+ *
+ * @relates asio::ip::address
+ */
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const address& addr);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/ip/impl/address.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ip/impl/address.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_IP_ADDRESS_HPP
diff --git a/subprojects/asio/include/asio/ip/address_v4.hpp b/subprojects/asio/include/asio/ip/address_v4.hpp
new file mode 100644
index 000000000..4e1cc9a33
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/address_v4.hpp
@@ -0,0 +1,329 @@
+//
+// ip/address_v4.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ADDRESS_V4_HPP
+#define ASIO_IP_ADDRESS_V4_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/array.hpp"
+#include "asio/detail/cstdint.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/string_view.hpp"
+#include "asio/detail/winsock_init.hpp"
+#include "asio/error_code.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+# include <iosfwd>
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Implements IP version 4 style addresses.
+/**
+ * The asio::ip::address_v4 class provides the ability to use and
+ * manipulate IP version 4 addresses.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class address_v4
+{
+public:
+  /// The type used to represent an address as an unsigned integer.
+  typedef uint_least32_t uint_type;
+
+  /// The type used to represent an address as an array of bytes.
+  /**
+   * @note This type is defined in terms of the C++0x template @c std::array
+   * when it is available. Otherwise, it uses @c boost:array.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef array<unsigned char, 4> bytes_type;
+#else
+  typedef asio::detail::array<unsigned char, 4> bytes_type;
+#endif
+
+  /// Default constructor.
+  address_v4()
+  {
+    addr_.s_addr = 0;
+  }
+
+  /// Construct an address from raw bytes.
+  ASIO_DECL explicit address_v4(const bytes_type& bytes);
+
+  /// Construct an address from an unsigned integer in host byte order.
+  ASIO_DECL explicit address_v4(uint_type addr);
+
+  /// Copy constructor.
+  address_v4(const address_v4& other)
+    : addr_(other.addr_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  address_v4(address_v4&& other)
+    : addr_(other.addr_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from another address.
+  address_v4& operator=(const address_v4& other)
+  {
+    addr_ = other.addr_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move-assign from another address.
+  address_v4& operator=(address_v4&& other)
+  {
+    addr_ = other.addr_;
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Get the address in bytes, in network byte order.
+  ASIO_DECL bytes_type to_bytes() const;
+
+  /// Get the address as an unsigned integer in host byte order
+  ASIO_DECL uint_type to_uint() const;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// Get the address as an unsigned long in host byte order
+  ASIO_DECL unsigned long to_ulong() const;
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the address as a string in dotted decimal format.
+  ASIO_DECL std::string to_string() const;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use other overload.) Get the address as a string in dotted
+  /// decimal format.
+  ASIO_DECL std::string to_string(asio::error_code& ec) const;
+
+  /// (Deprecated: Use make_address_v4().) Create an address from an IP address
+  /// string in dotted decimal form.
+  static address_v4 from_string(const char* str);
+
+  /// (Deprecated: Use make_address_v4().) Create an address from an IP address
+  /// string in dotted decimal form.
+  static address_v4 from_string(
+      const char* str, asio::error_code& ec);
+
+  /// (Deprecated: Use make_address_v4().) Create an address from an IP address
+  /// string in dotted decimal form.
+  static address_v4 from_string(const std::string& str);
+
+  /// (Deprecated: Use make_address_v4().) Create an address from an IP address
+  /// string in dotted decimal form.
+  static address_v4 from_string(
+      const std::string& str, asio::error_code& ec);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Determine whether the address is a loopback address.
+  ASIO_DECL bool is_loopback() const;
+
+  /// Determine whether the address is unspecified.
+  ASIO_DECL bool is_unspecified() const;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use network_v4 class.) Determine whether the address is a
+  /// class A address.
+  ASIO_DECL bool is_class_a() const;
+
+  /// (Deprecated: Use network_v4 class.) Determine whether the address is a
+  /// class B address.
+  ASIO_DECL bool is_class_b() const;
+
+  /// (Deprecated: Use network_v4 class.) Determine whether the address is a
+  /// class C address.
+  ASIO_DECL bool is_class_c() const;
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Determine whether the address is a multicast address.
+  ASIO_DECL bool is_multicast() const;
+
+  /// Compare two addresses for equality.
+  friend bool operator==(const address_v4& a1, const address_v4& a2)
+  {
+    return a1.addr_.s_addr == a2.addr_.s_addr;
+  }
+
+  /// Compare two addresses for inequality.
+  friend bool operator!=(const address_v4& a1, const address_v4& a2)
+  {
+    return a1.addr_.s_addr != a2.addr_.s_addr;
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator<(const address_v4& a1, const address_v4& a2)
+  {
+    return a1.to_uint() < a2.to_uint();
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator>(const address_v4& a1, const address_v4& a2)
+  {
+    return a1.to_uint() > a2.to_uint();
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator<=(const address_v4& a1, const address_v4& a2)
+  {
+    return a1.to_uint() <= a2.to_uint();
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator>=(const address_v4& a1, const address_v4& a2)
+  {
+    return a1.to_uint() >= a2.to_uint();
+  }
+
+  /// Obtain an address object that represents any address.
+  static address_v4 any()
+  {
+    return address_v4();
+  }
+
+  /// Obtain an address object that represents the loopback address.
+  static address_v4 loopback()
+  {
+    return address_v4(0x7F000001);
+  }
+
+  /// Obtain an address object that represents the broadcast address.
+  static address_v4 broadcast()
+  {
+    return address_v4(0xFFFFFFFF);
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use network_v4 class.) Obtain an address object that
+  /// represents the broadcast address that corresponds to the specified
+  /// address and netmask.
+  ASIO_DECL static address_v4 broadcast(
+      const address_v4& addr, const address_v4& mask);
+
+  /// (Deprecated: Use network_v4 class.) Obtain the netmask that corresponds
+  /// to the address, based on its address class.
+  ASIO_DECL static address_v4 netmask(const address_v4& addr);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+private:
+  // The underlying IPv4 address.
+  asio::detail::in4_addr_type addr_;
+};
+
+/// Create an IPv4 address from raw bytes in network order.
+/**
+ * @relates address_v4
+ */
+inline address_v4 make_address_v4(const address_v4::bytes_type& bytes)
+{
+  return address_v4(bytes);
+}
+
+/// Create an IPv4 address from an unsigned integer in host byte order.
+/**
+ * @relates address_v4
+ */
+inline address_v4 make_address_v4(address_v4::uint_type addr)
+{
+  return address_v4(addr);
+}
+
+/// Create an IPv4 address from an IP address string in dotted decimal form.
+/**
+ * @relates address_v4
+ */
+ASIO_DECL address_v4 make_address_v4(const char* str);
+
+/// Create an IPv4 address from an IP address string in dotted decimal form.
+/**
+ * @relates address_v4
+ */
+ASIO_DECL address_v4 make_address_v4(
+    const char* str, asio::error_code& ec);
+
+/// Create an IPv4 address from an IP address string in dotted decimal form.
+/**
+ * @relates address_v4
+ */
+ASIO_DECL address_v4 make_address_v4(const std::string& str);
+
+/// Create an IPv4 address from an IP address string in dotted decimal form.
+/**
+ * @relates address_v4
+ */
+ASIO_DECL address_v4 make_address_v4(
+    const std::string& str, asio::error_code& ec);
+
+#if defined(ASIO_HAS_STRING_VIEW) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Create an IPv4 address from an IP address string in dotted decimal form.
+/**
+ * @relates address_v4
+ */
+ASIO_DECL address_v4 make_address_v4(string_view str);
+
+/// Create an IPv4 address from an IP address string in dotted decimal form.
+/**
+ * @relates address_v4
+ */
+ASIO_DECL address_v4 make_address_v4(
+    string_view str, asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Output an address as a string.
+/**
+ * Used to output a human-readable string for a specified address.
+ *
+ * @param os The output stream to which the string will be written.
+ *
+ * @param addr The address to be written.
+ *
+ * @return The output stream.
+ *
+ * @relates asio::ip::address_v4
+ */
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const address_v4& addr);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/ip/impl/address_v4.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ip/impl/address_v4.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_IP_ADDRESS_V4_HPP
diff --git a/subprojects/asio/include/asio/ip/address_v4_iterator.hpp b/subprojects/asio/include/asio/ip/address_v4_iterator.hpp
new file mode 100644
index 000000000..e2ef3937e
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/address_v4_iterator.hpp
@@ -0,0 +1,162 @@
+//
+// ip/address_v4_iterator.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ADDRESS_V4_ITERATOR_HPP
+#define ASIO_IP_ADDRESS_V4_ITERATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ip/address_v4.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename> class basic_address_iterator;
+
+/// An input iterator that can be used for traversing IPv4 addresses.
+/**
+ * In addition to satisfying the input iterator requirements, this iterator
+ * also supports decrement.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <> class basic_address_iterator<address_v4>
+{
+public:
+  /// The type of the elements pointed to by the iterator.
+  typedef address_v4 value_type;
+
+  /// Distance between two iterators.
+  typedef std::ptrdiff_t difference_type;
+
+  /// The type of a pointer to an element pointed to by the iterator.
+  typedef const address_v4* pointer;
+
+  /// The type of a reference to an element pointed to by the iterator.
+  typedef const address_v4& reference;
+
+  /// Denotes that the iterator satisfies the input iterator requirements.
+  typedef std::input_iterator_tag iterator_category;
+
+  /// Construct an iterator that points to the specified address.
+  basic_address_iterator(const address_v4& addr) ASIO_NOEXCEPT
+    : address_(addr)
+  {
+  }
+
+  /// Copy constructor.
+  basic_address_iterator(
+      const basic_address_iterator& other) ASIO_NOEXCEPT
+    : address_(other.address_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  basic_address_iterator(basic_address_iterator&& other) ASIO_NOEXCEPT
+    : address_(ASIO_MOVE_CAST(address_v4)(other.address_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assignment operator.
+  basic_address_iterator& operator=(
+      const basic_address_iterator& other) ASIO_NOEXCEPT
+  {
+    address_ = other.address_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move assignment operator.
+  basic_address_iterator& operator=(
+      basic_address_iterator&& other) ASIO_NOEXCEPT
+  {
+    address_ = ASIO_MOVE_CAST(address_v4)(other.address_);
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Dereference the iterator.
+  const address_v4& operator*() const ASIO_NOEXCEPT
+  {
+    return address_;
+  }
+
+  /// Dereference the iterator.
+  const address_v4* operator->() const ASIO_NOEXCEPT
+  {
+    return &address_;
+  }
+
+  /// Pre-increment operator.
+  basic_address_iterator& operator++() ASIO_NOEXCEPT
+  {
+    address_ = address_v4((address_.to_uint() + 1) & 0xFFFFFFFF);
+    return *this;
+  }
+
+  /// Post-increment operator.
+  basic_address_iterator operator++(int) ASIO_NOEXCEPT
+  {
+    basic_address_iterator tmp(*this);
+    ++*this;
+    return tmp;
+  }
+
+  /// Pre-decrement operator.
+  basic_address_iterator& operator--() ASIO_NOEXCEPT
+  {
+    address_ = address_v4((address_.to_uint() - 1) & 0xFFFFFFFF);
+    return *this;
+  }
+
+  /// Post-decrement operator.
+  basic_address_iterator operator--(int)
+  {
+    basic_address_iterator tmp(*this);
+    --*this;
+    return tmp;
+  }
+
+  /// Compare two addresses for equality.
+  friend bool operator==(const basic_address_iterator& a,
+      const basic_address_iterator& b)
+  {
+    return a.address_ == b.address_;
+  }
+
+  /// Compare two addresses for inequality.
+  friend bool operator!=(const basic_address_iterator& a,
+      const basic_address_iterator& b)
+  {
+    return a.address_ != b.address_;
+  }
+
+private:
+  address_v4 address_;
+};
+
+/// An input iterator that can be used for traversing IPv4 addresses.
+typedef basic_address_iterator<address_v4> address_v4_iterator;
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_ADDRESS_V4_ITERATOR_HPP
diff --git a/subprojects/asio/include/asio/ip/address_v4_range.hpp b/subprojects/asio/include/asio/ip/address_v4_range.hpp
new file mode 100644
index 000000000..a40284208
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/address_v4_range.hpp
@@ -0,0 +1,134 @@
+//
+// ip/address_v4_range.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ADDRESS_V4_RANGE_HPP
+#define ASIO_IP_ADDRESS_V4_RANGE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ip/address_v4_iterator.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename> class basic_address_range;
+
+/// Represents a range of IPv4 addresses.
+/**
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <> class basic_address_range<address_v4>
+{
+public:
+  /// The type of an iterator that points into the range.
+  typedef basic_address_iterator<address_v4> iterator;
+
+  /// Construct an empty range.
+  basic_address_range() ASIO_NOEXCEPT
+    : begin_(address_v4()),
+      end_(address_v4())
+  {
+  }
+
+  /// Construct an range that represents the given range of addresses.
+  explicit basic_address_range(const iterator& first,
+      const iterator& last) ASIO_NOEXCEPT
+    : begin_(first),
+      end_(last)
+  {
+  }
+
+  /// Copy constructor.
+  basic_address_range(const basic_address_range& other) ASIO_NOEXCEPT
+    : begin_(other.begin_),
+      end_(other.end_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  basic_address_range(basic_address_range&& other) ASIO_NOEXCEPT
+    : begin_(ASIO_MOVE_CAST(iterator)(other.begin_)),
+      end_(ASIO_MOVE_CAST(iterator)(other.end_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assignment operator.
+  basic_address_range& operator=(
+      const basic_address_range& other) ASIO_NOEXCEPT
+  {
+    begin_ = other.begin_;
+    end_ = other.end_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move assignment operator.
+  basic_address_range& operator=(
+      basic_address_range&& other) ASIO_NOEXCEPT
+  {
+    begin_ = ASIO_MOVE_CAST(iterator)(other.begin_);
+    end_ = ASIO_MOVE_CAST(iterator)(other.end_);
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Obtain an iterator that points to the start of the range.
+  iterator begin() const ASIO_NOEXCEPT
+  {
+    return begin_;
+  }
+
+  /// Obtain an iterator that points to the end of the range.
+  iterator end() const ASIO_NOEXCEPT
+  {
+    return end_;
+  }
+
+  /// Determine whether the range is empty.
+  bool empty() const ASIO_NOEXCEPT
+  {
+    return size() == 0;
+  }
+
+  /// Return the size of the range.
+  std::size_t size() const ASIO_NOEXCEPT
+  {
+    return end_->to_uint() - begin_->to_uint();
+  }
+
+  /// Find an address in the range.
+  iterator find(const address_v4& addr) const ASIO_NOEXCEPT
+  {
+    return addr >= *begin_ && addr < *end_ ? iterator(addr) : end_;
+  }
+
+private:
+  iterator begin_;
+  iterator end_;
+};
+
+/// Represents a range of IPv4 addresses.
+typedef basic_address_range<address_v4> address_v4_range;
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_ADDRESS_V4_RANGE_HPP
diff --git a/subprojects/asio/include/asio/ip/address_v6.hpp b/subprojects/asio/include/asio/ip/address_v6.hpp
new file mode 100644
index 000000000..fece33297
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/address_v6.hpp
@@ -0,0 +1,336 @@
+//
+// ip/address_v6.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ADDRESS_V6_HPP
+#define ASIO_IP_ADDRESS_V6_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/array.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/string_view.hpp"
+#include "asio/detail/winsock_init.hpp"
+#include "asio/error_code.hpp"
+#include "asio/ip/address_v4.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+# include <iosfwd>
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename> class basic_address_iterator;
+
+/// Implements IP version 6 style addresses.
+/**
+ * The asio::ip::address_v6 class provides the ability to use and
+ * manipulate IP version 6 addresses.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class address_v6
+{
+public:
+  /// The type used to represent an address as an array of bytes.
+  /**
+   * @note This type is defined in terms of the C++0x template @c std::array
+   * when it is available. Otherwise, it uses @c boost:array.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef array<unsigned char, 16> bytes_type;
+#else
+  typedef asio::detail::array<unsigned char, 16> bytes_type;
+#endif
+
+  /// Default constructor.
+  ASIO_DECL address_v6();
+
+  /// Construct an address from raw bytes and scope ID.
+  ASIO_DECL explicit address_v6(const bytes_type& bytes,
+      unsigned long scope_id = 0);
+
+  /// Copy constructor.
+  ASIO_DECL address_v6(const address_v6& other);
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  ASIO_DECL address_v6(address_v6&& other);
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from another address.
+  ASIO_DECL address_v6& operator=(const address_v6& other);
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move-assign from another address.
+  ASIO_DECL address_v6& operator=(address_v6&& other);
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// The scope ID of the address.
+  /**
+   * Returns the scope ID associated with the IPv6 address.
+   */
+  unsigned long scope_id() const
+  {
+    return scope_id_;
+  }
+
+  /// The scope ID of the address.
+  /**
+   * Modifies the scope ID associated with the IPv6 address.
+   */
+  void scope_id(unsigned long id)
+  {
+    scope_id_ = id;
+  }
+
+  /// Get the address in bytes, in network byte order.
+  ASIO_DECL bytes_type to_bytes() const;
+
+  /// Get the address as a string.
+  ASIO_DECL std::string to_string() const;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use other overload.) Get the address as a string.
+  ASIO_DECL std::string to_string(asio::error_code& ec) const;
+
+  /// (Deprecated: Use make_address_v6().) Create an IPv6 address from an IP
+  /// address string.
+  static address_v6 from_string(const char* str);
+
+  /// (Deprecated: Use make_address_v6().) Create an IPv6 address from an IP
+  /// address string.
+  static address_v6 from_string(
+      const char* str, asio::error_code& ec);
+
+  /// (Deprecated: Use make_address_v6().) Create an IPv6 address from an IP
+  /// address string.
+  static address_v6 from_string(const std::string& str);
+
+  /// (Deprecated: Use make_address_v6().) Create an IPv6 address from an IP
+  /// address string.
+  static address_v6 from_string(
+      const std::string& str, asio::error_code& ec);
+
+  /// (Deprecated: Use make_address_v4().) Converts an IPv4-mapped or
+  /// IPv4-compatible address to an IPv4 address.
+  ASIO_DECL address_v4 to_v4() const;
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Determine whether the address is a loopback address.
+  ASIO_DECL bool is_loopback() const;
+
+  /// Determine whether the address is unspecified.
+  ASIO_DECL bool is_unspecified() const;
+
+  /// Determine whether the address is link local.
+  ASIO_DECL bool is_link_local() const;
+
+  /// Determine whether the address is site local.
+  ASIO_DECL bool is_site_local() const;
+
+  /// Determine whether the address is a mapped IPv4 address.
+  ASIO_DECL bool is_v4_mapped() const;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: No replacement.) Determine whether the address is an
+  /// IPv4-compatible address.
+  ASIO_DECL bool is_v4_compatible() const;
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Determine whether the address is a multicast address.
+  ASIO_DECL bool is_multicast() const;
+
+  /// Determine whether the address is a global multicast address.
+  ASIO_DECL bool is_multicast_global() const;
+
+  /// Determine whether the address is a link-local multicast address.
+  ASIO_DECL bool is_multicast_link_local() const;
+
+  /// Determine whether the address is a node-local multicast address.
+  ASIO_DECL bool is_multicast_node_local() const;
+
+  /// Determine whether the address is a org-local multicast address.
+  ASIO_DECL bool is_multicast_org_local() const;
+
+  /// Determine whether the address is a site-local multicast address.
+  ASIO_DECL bool is_multicast_site_local() const;
+
+  /// Compare two addresses for equality.
+  ASIO_DECL friend bool operator==(
+      const address_v6& a1, const address_v6& a2);
+
+  /// Compare two addresses for inequality.
+  friend bool operator!=(const address_v6& a1, const address_v6& a2)
+  {
+    return !(a1 == a2);
+  }
+
+  /// Compare addresses for ordering.
+  ASIO_DECL friend bool operator<(
+      const address_v6& a1, const address_v6& a2);
+
+  /// Compare addresses for ordering.
+  friend bool operator>(const address_v6& a1, const address_v6& a2)
+  {
+    return a2 < a1;
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator<=(const address_v6& a1, const address_v6& a2)
+  {
+    return !(a2 < a1);
+  }
+
+  /// Compare addresses for ordering.
+  friend bool operator>=(const address_v6& a1, const address_v6& a2)
+  {
+    return !(a1 < a2);
+  }
+
+  /// Obtain an address object that represents any address.
+  static address_v6 any()
+  {
+    return address_v6();
+  }
+
+  /// Obtain an address object that represents the loopback address.
+  ASIO_DECL static address_v6 loopback();
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use make_address_v6().) Create an IPv4-mapped IPv6 address.
+  ASIO_DECL static address_v6 v4_mapped(const address_v4& addr);
+
+  /// (Deprecated: No replacement.) Create an IPv4-compatible IPv6 address.
+  ASIO_DECL static address_v6 v4_compatible(const address_v4& addr);
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+private:
+  friend class basic_address_iterator<address_v6>;
+
+  // The underlying IPv6 address.
+  asio::detail::in6_addr_type addr_;
+
+  // The scope ID associated with the address.
+  unsigned long scope_id_;
+};
+
+/// Create an IPv6 address from raw bytes and scope ID.
+/**
+ * @relates address_v6
+ */
+inline address_v6 make_address_v6(const address_v6::bytes_type& bytes,
+    unsigned long scope_id = 0)
+{
+  return address_v6(bytes, scope_id);
+}
+
+/// Create an IPv6 address from an IP address string.
+/**
+ * @relates address_v6
+ */
+ASIO_DECL address_v6 make_address_v6(const char* str);
+
+/// Create an IPv6 address from an IP address string.
+/**
+ * @relates address_v6
+ */
+ASIO_DECL address_v6 make_address_v6(
+    const char* str, asio::error_code& ec);
+
+/// Createan IPv6 address from an IP address string.
+/**
+ * @relates address_v6
+ */
+ASIO_DECL address_v6 make_address_v6(const std::string& str);
+
+/// Create an IPv6 address from an IP address string.
+/**
+ * @relates address_v6
+ */
+ASIO_DECL address_v6 make_address_v6(
+    const std::string& str, asio::error_code& ec);
+
+#if defined(ASIO_HAS_STRING_VIEW) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Create an IPv6 address from an IP address string.
+/**
+ * @relates address_v6
+ */
+ASIO_DECL address_v6 make_address_v6(string_view str);
+
+/// Create an IPv6 address from an IP address string.
+/**
+ * @relates address_v6
+ */
+ASIO_DECL address_v6 make_address_v6(
+    string_view str, asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
+/// Tag type used for distinguishing overloads that deal in IPv4-mapped IPv6
+/// addresses.
+enum v4_mapped_t { v4_mapped };
+
+/// Create an IPv4 address from a IPv4-mapped IPv6 address.
+/**
+ * @relates address_v4
+ */
+ASIO_DECL address_v4 make_address_v4(
+    v4_mapped_t, const address_v6& v6_addr);
+
+/// Create an IPv4-mapped IPv6 address from an IPv4 address.
+/**
+ * @relates address_v6
+ */
+ASIO_DECL address_v6 make_address_v6(
+    v4_mapped_t, const address_v4& v4_addr);
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Output an address as a string.
+/**
+ * Used to output a human-readable string for a specified address.
+ *
+ * @param os The output stream to which the string will be written.
+ *
+ * @param addr The address to be written.
+ *
+ * @return The output stream.
+ *
+ * @relates asio::ip::address_v6
+ */
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const address_v6& addr);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/ip/impl/address_v6.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ip/impl/address_v6.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_IP_ADDRESS_V6_HPP
diff --git a/subprojects/asio/include/asio/ip/address_v6_iterator.hpp b/subprojects/asio/include/asio/ip/address_v6_iterator.hpp
new file mode 100644
index 000000000..0a1fb3fea
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/address_v6_iterator.hpp
@@ -0,0 +1,183 @@
+//
+// ip/address_v6_iterator.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//                         Oliver Kowalke (oliver dot kowalke at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ADDRESS_V6_ITERATOR_HPP
+#define ASIO_IP_ADDRESS_V6_ITERATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ip/address_v6.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename> class basic_address_iterator;
+
+/// An input iterator that can be used for traversing IPv6 addresses.
+/**
+ * In addition to satisfying the input iterator requirements, this iterator
+ * also supports decrement.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <> class basic_address_iterator<address_v6>
+{
+public:
+  /// The type of the elements pointed to by the iterator.
+  typedef address_v6 value_type;
+
+  /// Distance between two iterators.
+  typedef std::ptrdiff_t difference_type;
+
+  /// The type of a pointer to an element pointed to by the iterator.
+  typedef const address_v6* pointer;
+
+  /// The type of a reference to an element pointed to by the iterator.
+  typedef const address_v6& reference;
+
+  /// Denotes that the iterator satisfies the input iterator requirements.
+  typedef std::input_iterator_tag iterator_category;
+
+  /// Construct an iterator that points to the specified address.
+  basic_address_iterator(const address_v6& addr) ASIO_NOEXCEPT
+    : address_(addr)
+  {
+  }
+
+  /// Copy constructor.
+  basic_address_iterator(
+      const basic_address_iterator& other) ASIO_NOEXCEPT
+    : address_(other.address_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  basic_address_iterator(basic_address_iterator&& other) ASIO_NOEXCEPT
+    : address_(ASIO_MOVE_CAST(address_v6)(other.address_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assignment operator.
+  basic_address_iterator& operator=(
+      const basic_address_iterator& other) ASIO_NOEXCEPT
+  {
+    address_ = other.address_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move assignment operator.
+  basic_address_iterator& operator=(
+      basic_address_iterator&& other) ASIO_NOEXCEPT
+  {
+    address_ = ASIO_MOVE_CAST(address_v6)(other.address_);
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Dereference the iterator.
+  const address_v6& operator*() const ASIO_NOEXCEPT
+  {
+    return address_;
+  }
+
+  /// Dereference the iterator.
+  const address_v6* operator->() const ASIO_NOEXCEPT
+  {
+    return &address_;
+  }
+
+  /// Pre-increment operator.
+  basic_address_iterator& operator++() ASIO_NOEXCEPT
+  {
+    for (int i = 15; i >= 0; --i)
+    {
+      if (address_.addr_.s6_addr[i] < 0xFF)
+      {
+        ++address_.addr_.s6_addr[i];
+        break;
+      }
+
+      address_.addr_.s6_addr[i] = 0;
+    }
+
+    return *this;
+  }
+
+  /// Post-increment operator.
+  basic_address_iterator operator++(int) ASIO_NOEXCEPT
+  {
+    basic_address_iterator tmp(*this);
+    ++*this;
+    return tmp;
+  }
+
+  /// Pre-decrement operator.
+  basic_address_iterator& operator--() ASIO_NOEXCEPT
+  {
+    for (int i = 15; i >= 0; --i)
+    {
+      if (address_.addr_.s6_addr[i] > 0)
+      {
+        --address_.addr_.s6_addr[i];
+        break;
+      }
+
+      address_.addr_.s6_addr[i] = 0xFF;
+    }
+
+    return *this;
+  }
+
+  /// Post-decrement operator.
+  basic_address_iterator operator--(int)
+  {
+    basic_address_iterator tmp(*this);
+    --*this;
+    return tmp;
+  }
+
+  /// Compare two addresses for equality.
+  friend bool operator==(const basic_address_iterator& a,
+      const basic_address_iterator& b)
+  {
+    return a.address_ == b.address_;
+  }
+
+  /// Compare two addresses for inequality.
+  friend bool operator!=(const basic_address_iterator& a,
+      const basic_address_iterator& b)
+  {
+    return a.address_ != b.address_;
+  }
+
+private:
+  address_v6 address_;
+};
+
+/// An input iterator that can be used for traversing IPv6 addresses.
+typedef basic_address_iterator<address_v6> address_v6_iterator;
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_ADDRESS_V6_ITERATOR_HPP
diff --git a/subprojects/asio/include/asio/ip/address_v6_range.hpp b/subprojects/asio/include/asio/ip/address_v6_range.hpp
new file mode 100644
index 000000000..9d7062ef8
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/address_v6_range.hpp
@@ -0,0 +1,129 @@
+//
+// ip/address_v6_range.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//                         Oliver Kowalke (oliver dot kowalke at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ADDRESS_V6_RANGE_HPP
+#define ASIO_IP_ADDRESS_V6_RANGE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ip/address_v6_iterator.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename> class basic_address_range;
+
+/// Represents a range of IPv6 addresses.
+/**
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <> class basic_address_range<address_v6>
+{
+public:
+  /// The type of an iterator that points into the range.
+  typedef basic_address_iterator<address_v6> iterator;
+
+  /// Construct an empty range.
+  basic_address_range() ASIO_NOEXCEPT
+    : begin_(address_v6()),
+      end_(address_v6())
+  {
+  }
+
+  /// Construct an range that represents the given range of addresses.
+  explicit basic_address_range(const iterator& first,
+      const iterator& last) ASIO_NOEXCEPT
+    : begin_(first),
+      end_(last)
+  {
+  }
+
+  /// Copy constructor.
+  basic_address_range(const basic_address_range& other) ASIO_NOEXCEPT
+    : begin_(other.begin_),
+      end_(other.end_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  basic_address_range(basic_address_range&& other) ASIO_NOEXCEPT
+    : begin_(ASIO_MOVE_CAST(iterator)(other.begin_)),
+      end_(ASIO_MOVE_CAST(iterator)(other.end_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assignment operator.
+  basic_address_range& operator=(
+      const basic_address_range& other) ASIO_NOEXCEPT
+  {
+    begin_ = other.begin_;
+    end_ = other.end_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move assignment operator.
+  basic_address_range& operator=(
+      basic_address_range&& other) ASIO_NOEXCEPT
+  {
+    begin_ = ASIO_MOVE_CAST(iterator)(other.begin_);
+    end_ = ASIO_MOVE_CAST(iterator)(other.end_);
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Obtain an iterator that points to the start of the range.
+  iterator begin() const ASIO_NOEXCEPT
+  {
+    return begin_;
+  }
+
+  /// Obtain an iterator that points to the end of the range.
+  iterator end() const ASIO_NOEXCEPT
+  {
+    return end_;
+  }
+
+  /// Determine whether the range is empty.
+  bool empty() const ASIO_NOEXCEPT
+  {
+    return begin_ == end_;
+  }
+
+  /// Find an address in the range.
+  iterator find(const address_v6& addr) const ASIO_NOEXCEPT
+  {
+    return addr >= *begin_ && addr < *end_ ? iterator(addr) : end_;
+  }
+
+private:
+  iterator begin_;
+  iterator end_;
+};
+
+/// Represents a range of IPv6 addresses.
+typedef basic_address_range<address_v6> address_v6_range;
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_ADDRESS_V6_RANGE_HPP
diff --git a/subprojects/asio/include/asio/ip/bad_address_cast.hpp b/subprojects/asio/include/asio/ip/bad_address_cast.hpp
new file mode 100644
index 000000000..0838d4a71
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/bad_address_cast.hpp
@@ -0,0 +1,53 @@
+//
+// ip/bad_address_cast.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_BAD_ADDRESS_CAST_HPP
+#define ASIO_IP_BAD_ADDRESS_CAST_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <typeinfo>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Thrown to indicate a failed address conversion.
+class bad_address_cast :
+#if defined(ASIO_MSVC) && defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS
+  public std::exception
+#else
+  public std::bad_cast
+#endif
+{
+public:
+  /// Default constructor.
+  bad_address_cast() {}
+
+  /// Destructor.
+  virtual ~bad_address_cast() ASIO_NOEXCEPT_OR_NOTHROW {}
+
+  /// Get the message associated with the exception.
+  virtual const char* what() const ASIO_NOEXCEPT_OR_NOTHROW
+  {
+    return "bad address cast";
+  }
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_ADDRESS_HPP
diff --git a/subprojects/asio/include/asio/ip/basic_endpoint.hpp b/subprojects/asio/include/asio/ip/basic_endpoint.hpp
new file mode 100644
index 000000000..4418ee776
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/basic_endpoint.hpp
@@ -0,0 +1,263 @@
+//
+// ip/basic_endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_BASIC_ENDPOINT_HPP
+#define ASIO_IP_BASIC_ENDPOINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ip/address.hpp"
+#include "asio/ip/detail/endpoint.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+# include <iosfwd>
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Describes an endpoint for a version-independent IP socket.
+/**
+ * The asio::ip::basic_endpoint class template describes an endpoint that
+ * may be associated with a particular socket.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * Endpoint.
+ */
+template <typename InternetProtocol>
+class basic_endpoint
+{
+public:
+  /// The protocol type associated with the endpoint.
+  typedef InternetProtocol protocol_type;
+
+  /// The type of the endpoint structure. This type is dependent on the
+  /// underlying implementation of the socket layer.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined data_type;
+#else
+  typedef asio::detail::socket_addr_type data_type;
+#endif
+
+  /// Default constructor.
+  basic_endpoint()
+    : impl_()
+  {
+  }
+
+  /// Construct an endpoint using a port number, specified in the host's byte
+  /// order. The IP address will be the any address (i.e. INADDR_ANY or
+  /// in6addr_any). This constructor would typically be used for accepting new
+  /// connections.
+  /**
+   * @par Examples
+   * To initialise an IPv4 TCP endpoint for port 1234, use:
+   * @code
+   * asio::ip::tcp::endpoint ep(asio::ip::tcp::v4(), 1234);
+   * @endcode
+   *
+   * To specify an IPv6 UDP endpoint for port 9876, use:
+   * @code
+   * asio::ip::udp::endpoint ep(asio::ip::udp::v6(), 9876);
+   * @endcode
+   */
+  basic_endpoint(const InternetProtocol& internet_protocol,
+      unsigned short port_num)
+    : impl_(internet_protocol.family(), port_num)
+  {
+  }
+
+  /// Construct an endpoint using a port number and an IP address. This
+  /// constructor may be used for accepting connections on a specific interface
+  /// or for making a connection to a remote endpoint.
+  basic_endpoint(const asio::ip::address& addr, unsigned short port_num)
+    : impl_(addr, port_num)
+  {
+  }
+
+  /// Copy constructor.
+  basic_endpoint(const basic_endpoint& other)
+    : impl_(other.impl_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move constructor.
+  basic_endpoint(basic_endpoint&& other)
+    : impl_(other.impl_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Assign from another endpoint.
+  basic_endpoint& operator=(const basic_endpoint& other)
+  {
+    impl_ = other.impl_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-assign from another endpoint.
+  basic_endpoint& operator=(basic_endpoint&& other)
+  {
+    impl_ = other.impl_;
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// The protocol associated with the endpoint.
+  protocol_type protocol() const
+  {
+    if (impl_.is_v4())
+      return InternetProtocol::v4();
+    return InternetProtocol::v6();
+  }
+
+  /// Get the underlying endpoint in the native type.
+  data_type* data()
+  {
+    return impl_.data();
+  }
+
+  /// Get the underlying endpoint in the native type.
+  const data_type* data() const
+  {
+    return impl_.data();
+  }
+
+  /// Get the underlying size of the endpoint in the native type.
+  std::size_t size() const
+  {
+    return impl_.size();
+  }
+
+  /// Set the underlying size of the endpoint in the native type.
+  void resize(std::size_t new_size)
+  {
+    impl_.resize(new_size);
+  }
+
+  /// Get the capacity of the endpoint in the native type.
+  std::size_t capacity() const
+  {
+    return impl_.capacity();
+  }
+
+  /// Get the port associated with the endpoint. The port number is always in
+  /// the host's byte order.
+  unsigned short port() const
+  {
+    return impl_.port();
+  }
+
+  /// Set the port associated with the endpoint. The port number is always in
+  /// the host's byte order.
+  void port(unsigned short port_num)
+  {
+    impl_.port(port_num);
+  }
+
+  /// Get the IP address associated with the endpoint.
+  asio::ip::address address() const
+  {
+    return impl_.address();
+  }
+
+  /// Set the IP address associated with the endpoint.
+  void address(const asio::ip::address& addr)
+  {
+    impl_.address(addr);
+  }
+
+  /// Compare two endpoints for equality.
+  friend bool operator==(const basic_endpoint<InternetProtocol>& e1,
+      const basic_endpoint<InternetProtocol>& e2)
+  {
+    return e1.impl_ == e2.impl_;
+  }
+
+  /// Compare two endpoints for inequality.
+  friend bool operator!=(const basic_endpoint<InternetProtocol>& e1,
+      const basic_endpoint<InternetProtocol>& e2)
+  {
+    return !(e1 == e2);
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator<(const basic_endpoint<InternetProtocol>& e1,
+      const basic_endpoint<InternetProtocol>& e2)
+  {
+    return e1.impl_ < e2.impl_;
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator>(const basic_endpoint<InternetProtocol>& e1,
+      const basic_endpoint<InternetProtocol>& e2)
+  {
+    return e2.impl_ < e1.impl_;
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator<=(const basic_endpoint<InternetProtocol>& e1,
+      const basic_endpoint<InternetProtocol>& e2)
+  {
+    return !(e2 < e1);
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator>=(const basic_endpoint<InternetProtocol>& e1,
+      const basic_endpoint<InternetProtocol>& e2)
+  {
+    return !(e1 < e2);
+  }
+
+private:
+  // The underlying IP endpoint.
+  asio::ip::detail::endpoint impl_;
+};
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Output an endpoint as a string.
+/**
+ * Used to output a human-readable string for a specified endpoint.
+ *
+ * @param os The output stream to which the string will be written.
+ *
+ * @param endpoint The endpoint to be written.
+ *
+ * @return The output stream.
+ *
+ * @relates asio::ip::basic_endpoint
+ */
+template <typename Elem, typename Traits, typename InternetProtocol>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os,
+    const basic_endpoint<InternetProtocol>& endpoint);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/ip/impl/basic_endpoint.hpp"
+
+#endif // ASIO_IP_BASIC_ENDPOINT_HPP
diff --git a/subprojects/asio/include/asio/ip/basic_resolver.hpp b/subprojects/asio/include/asio/ip/basic_resolver.hpp
new file mode 100644
index 000000000..9f4089568
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/basic_resolver.hpp
@@ -0,0 +1,1020 @@
+//
+// ip/basic_resolver.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_BASIC_RESOLVER_HPP
+#define ASIO_IP_BASIC_RESOLVER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/async_result.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/string_view.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+#include "asio/ip/basic_resolver_results.hpp"
+#include "asio/ip/resolver_base.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/ip/resolver_service.hpp"
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+# if defined(ASIO_WINDOWS_RUNTIME)
+#  include "asio/detail/winrt_resolver_service.hpp"
+#  define ASIO_SVC_T \
+    asio::detail::winrt_resolver_service<InternetProtocol>
+# else
+#  include "asio/detail/resolver_service.hpp"
+#  define ASIO_SVC_T \
+    asio::detail::resolver_service<InternetProtocol>
+# endif
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Provides endpoint resolution functionality.
+/**
+ * The basic_resolver class template provides the ability to resolve a query
+ * to a list of endpoints.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename InternetProtocol
+    ASIO_SVC_TPARAM_DEF1(= resolver_service<InternetProtocol>)>
+class basic_resolver
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>,
+    public resolver_base
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The protocol type.
+  typedef InternetProtocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename InternetProtocol::endpoint endpoint_type;
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated.) The query type.
+  typedef basic_resolver_query<InternetProtocol> query;
+
+  /// (Deprecated.) The iterator type.
+  typedef basic_resolver_iterator<InternetProtocol> iterator;
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// The results type.
+  typedef basic_resolver_results<InternetProtocol> results_type;
+
+  /// Constructor.
+  /**
+   * This constructor creates a basic_resolver.
+   *
+   * @param io_context The io_context object that the resolver will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * resolver.
+   */
+  explicit basic_resolver(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_resolver from another.
+  /**
+   * This constructor moves a resolver from one object to another.
+   *
+   * @param other The other basic_resolver object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_resolver(io_context&) constructor.
+   */
+  basic_resolver(basic_resolver&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign a basic_resolver from another.
+  /**
+   * This assignment operator moves a resolver from one object to another.
+   * Cancels any outstanding asynchronous operations associated with the target
+   * object.
+   *
+   * @param other The other basic_resolver object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_resolver(io_context&) constructor.
+   */
+  basic_resolver& operator=(basic_resolver&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the resolver.
+  /**
+   * This function destroys the resolver, cancelling any outstanding
+   * asynchronous wait operations associated with the resolver as if by calling
+   * @c cancel.
+   */
+  ~basic_resolver()
+  {
+  }
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+  // These functions are provided by basic_io_object<>.
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+  /// Cancel any asynchronous operations that are waiting on the resolver.
+  /**
+   * This function forces the completion of any pending asynchronous
+   * operations on the host resolver. The handler for each cancelled operation
+   * will be invoked with the asio::error::operation_aborted error code.
+   */
+  void cancel()
+  {
+    return this->get_service().cancel(this->get_implementation());
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use overload with separate host and service parameters.)
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve a query into a list of endpoint entries.
+   *
+   * @param q A query object that determines what endpoints will be returned.
+   *
+   * @returns A range object representing the list of endpoint entries. A
+   * successful call to this function is guaranteed to return a non-empty
+   * range.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  results_type resolve(const query& q)
+  {
+    asio::error_code ec;
+    results_type r = this->get_service().resolve(
+        this->get_implementation(), q, ec);
+    asio::detail::throw_error(ec, "resolve");
+    return r;
+  }
+
+  /// (Deprecated: Use overload with separate host and service parameters.)
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve a query into a list of endpoint entries.
+   *
+   * @param q A query object that determines what endpoints will be returned.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns A range object representing the list of endpoint entries. An
+   * empty range is returned if an error occurs. A successful call to this
+   * function is guaranteed to return a non-empty range.
+   */
+  results_type resolve(const query& q, asio::error_code& ec)
+  {
+    return this->get_service().resolve(this->get_implementation(), q, ec);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @returns A range object representing the list of endpoint entries. A
+   * successful call to this function is guaranteed to return a non-empty
+   * range.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(ASIO_STRING_VIEW_PARAM host,
+      ASIO_STRING_VIEW_PARAM service)
+  {
+    return resolve(host, service, resolver_base::flags());
+  }
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns A range object representing the list of endpoint entries. An
+   * empty range is returned if an error occurs. A successful call to this
+   * function is guaranteed to return a non-empty range.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(ASIO_STRING_VIEW_PARAM host,
+      ASIO_STRING_VIEW_PARAM service, asio::error_code& ec)
+  {
+    return resolve(host, service, resolver_base::flags(), ec);
+  }
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @returns A range object representing the list of endpoint entries. A
+   * successful call to this function is guaranteed to return a non-empty
+   * range.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(ASIO_STRING_VIEW_PARAM host,
+      ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags)
+  {
+    asio::error_code ec;
+    basic_resolver_query<protocol_type> q(static_cast<std::string>(host),
+        static_cast<std::string>(service), resolve_flags);
+    results_type r = this->get_service().resolve(
+        this->get_implementation(), q, ec);
+    asio::detail::throw_error(ec, "resolve");
+    return r;
+  }
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns A range object representing the list of endpoint entries. An
+   * empty range is returned if an error occurs. A successful call to this
+   * function is guaranteed to return a non-empty range.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(ASIO_STRING_VIEW_PARAM host,
+      ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags,
+      asio::error_code& ec)
+  {
+    basic_resolver_query<protocol_type> q(static_cast<std::string>(host),
+        static_cast<std::string>(service), resolve_flags);
+    return this->get_service().resolve(this->get_implementation(), q, ec);
+  }
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @returns A range object representing the list of endpoint entries. A
+   * successful call to this function is guaranteed to return a non-empty
+   * range.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(const protocol_type& protocol,
+      ASIO_STRING_VIEW_PARAM host, ASIO_STRING_VIEW_PARAM service)
+  {
+    return resolve(protocol, host, service, resolver_base::flags());
+  }
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns A range object representing the list of endpoint entries. An
+   * empty range is returned if an error occurs. A successful call to this
+   * function is guaranteed to return a non-empty range.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(const protocol_type& protocol,
+      ASIO_STRING_VIEW_PARAM host, ASIO_STRING_VIEW_PARAM service,
+      asio::error_code& ec)
+  {
+    return resolve(protocol, host, service, resolver_base::flags(), ec);
+  }
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @returns A range object representing the list of endpoint entries. A
+   * successful call to this function is guaranteed to return a non-empty
+   * range.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(const protocol_type& protocol,
+      ASIO_STRING_VIEW_PARAM host, ASIO_STRING_VIEW_PARAM service,
+      resolver_base::flags resolve_flags)
+  {
+    asio::error_code ec;
+    basic_resolver_query<protocol_type> q(
+        protocol, static_cast<std::string>(host),
+        static_cast<std::string>(service), resolve_flags);
+    results_type r = this->get_service().resolve(
+        this->get_implementation(), q, ec);
+    asio::detail::throw_error(ec, "resolve");
+    return r;
+  }
+
+  /// Perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns A range object representing the list of endpoint entries. An
+   * empty range is returned if an error occurs. A successful call to this
+   * function is guaranteed to return a non-empty range.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  results_type resolve(const protocol_type& protocol,
+      ASIO_STRING_VIEW_PARAM host, ASIO_STRING_VIEW_PARAM service,
+      resolver_base::flags resolve_flags, asio::error_code& ec)
+  {
+    basic_resolver_query<protocol_type> q(
+        protocol, static_cast<std::string>(host),
+        static_cast<std::string>(service), resolve_flags);
+    return this->get_service().resolve(this->get_implementation(), q, ec);
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use overload with separate host and service parameters.)
+  /// Asynchronously perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to asynchronously resolve a query into a list of
+   * endpoint entries.
+   *
+   * @param q A query object that determines what endpoints will be returned.
+   *
+   * @param handler The handler to be called when the resolve operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   resolver::results_type results // Resolved endpoints as a range.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * A successful resolve operation is guaranteed to pass a non-empty range to
+   * the handler.
+   */
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(const query& q,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ResolveHandler.
+    ASIO_RESOLVE_HANDLER_CHECK(
+        ResolveHandler, handler, results_type) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_resolve(this->get_implementation(), q,
+        ASIO_MOVE_CAST(ResolveHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    asio::async_completion<ResolveHandler,
+      void (asio::error_code, results_type)> init(handler);
+
+    this->get_service().async_resolve(
+        this->get_implementation(), q, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Asynchronously perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param handler The handler to be called when the resolve operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   resolver::results_type results // Resolved endpoints as a range.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * A successful resolve operation is guaranteed to pass a non-empty range to
+   * the handler.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(ASIO_STRING_VIEW_PARAM host,
+      ASIO_STRING_VIEW_PARAM service,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    return async_resolve(host, service, resolver_base::flags(),
+        ASIO_MOVE_CAST(ResolveHandler)(handler));
+  }
+
+  /// Asynchronously perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @param handler The handler to be called when the resolve operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   resolver::results_type results // Resolved endpoints as a range.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * A successful resolve operation is guaranteed to pass a non-empty range to
+   * the handler.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(ASIO_STRING_VIEW_PARAM host,
+      ASIO_STRING_VIEW_PARAM service,
+      resolver_base::flags resolve_flags,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ResolveHandler.
+    ASIO_RESOLVE_HANDLER_CHECK(
+        ResolveHandler, handler, results_type) type_check;
+
+    basic_resolver_query<protocol_type> q(static_cast<std::string>(host),
+        static_cast<std::string>(service), resolve_flags);
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_resolve(this->get_implementation(), q,
+        ASIO_MOVE_CAST(ResolveHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    asio::async_completion<ResolveHandler,
+      void (asio::error_code, results_type)> init(handler);
+
+    this->get_service().async_resolve(
+        this->get_implementation(), q, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Asynchronously perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param handler The handler to be called when the resolve operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   resolver::results_type results // Resolved endpoints as a range.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * A successful resolve operation is guaranteed to pass a non-empty range to
+   * the handler.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(const protocol_type& protocol,
+      ASIO_STRING_VIEW_PARAM host, ASIO_STRING_VIEW_PARAM service,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    return async_resolve(protocol, host, service, resolver_base::flags(),
+        ASIO_MOVE_CAST(ResolveHandler)(handler));
+  }
+
+  /// Asynchronously perform forward resolution of a query to a list of entries.
+  /**
+   * This function is used to resolve host and service names into a list of
+   * endpoint entries.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @param handler The handler to be called when the resolve operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   resolver::results_type results // Resolved endpoints as a range.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * A successful resolve operation is guaranteed to pass a non-empty range to
+   * the handler.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(const protocol_type& protocol,
+      ASIO_STRING_VIEW_PARAM host, ASIO_STRING_VIEW_PARAM service,
+      resolver_base::flags resolve_flags,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ResolveHandler.
+    ASIO_RESOLVE_HANDLER_CHECK(
+        ResolveHandler, handler, results_type) type_check;
+
+    basic_resolver_query<protocol_type> q(
+        protocol, static_cast<std::string>(host),
+        static_cast<std::string>(service), resolve_flags);
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_resolve(this->get_implementation(), q,
+        ASIO_MOVE_CAST(ResolveHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    asio::async_completion<ResolveHandler,
+      void (asio::error_code, results_type)> init(handler);
+
+    this->get_service().async_resolve(
+        this->get_implementation(), q, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+
+  /// Perform reverse resolution of an endpoint to a list of entries.
+  /**
+   * This function is used to resolve an endpoint into a list of endpoint
+   * entries.
+   *
+   * @param e An endpoint object that determines what endpoints will be
+   * returned.
+   *
+   * @returns A range object representing the list of endpoint entries. A
+   * successful call to this function is guaranteed to return a non-empty
+   * range.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  results_type resolve(const endpoint_type& e)
+  {
+    asio::error_code ec;
+    results_type i = this->get_service().resolve(
+        this->get_implementation(), e, ec);
+    asio::detail::throw_error(ec, "resolve");
+    return i;
+  }
+
+  /// Perform reverse resolution of an endpoint to a list of entries.
+  /**
+   * This function is used to resolve an endpoint into a list of endpoint
+   * entries.
+   *
+   * @param e An endpoint object that determines what endpoints will be
+   * returned.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns A range object representing the list of endpoint entries. An
+   * empty range is returned if an error occurs. A successful call to this
+   * function is guaranteed to return a non-empty range.
+   */
+  results_type resolve(const endpoint_type& e, asio::error_code& ec)
+  {
+    return this->get_service().resolve(this->get_implementation(), e, ec);
+  }
+
+  /// Asynchronously perform reverse resolution of an endpoint to a list of
+  /// entries.
+  /**
+   * This function is used to asynchronously resolve an endpoint into a list of
+   * endpoint entries.
+   *
+   * @param e An endpoint object that determines what endpoints will be
+   * returned.
+   *
+   * @param handler The handler to be called when the resolve operation
+   * completes. Copies will be made of the handler as required. The function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   resolver::results_type results // Resolved endpoints as a range.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * A successful resolve operation is guaranteed to pass a non-empty range to
+   * the handler.
+   */
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(const endpoint_type& e,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ResolveHandler.
+    ASIO_RESOLVE_HANDLER_CHECK(
+        ResolveHandler, handler, results_type) type_check;
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+    return this->get_service().async_resolve(this->get_implementation(), e,
+        ASIO_MOVE_CAST(ResolveHandler)(handler));
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+    asio::async_completion<ResolveHandler,
+      void (asio::error_code, results_type)> init(handler);
+
+    this->get_service().async_resolve(
+        this->get_implementation(), e, init.completion_handler);
+
+    return init.result.get();
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+  }
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# undef ASIO_SVC_T
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_IP_BASIC_RESOLVER_HPP
diff --git a/subprojects/asio/include/asio/ip/basic_resolver_entry.hpp b/subprojects/asio/include/asio/ip/basic_resolver_entry.hpp
new file mode 100644
index 000000000..99bcbd29e
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/basic_resolver_entry.hpp
@@ -0,0 +1,113 @@
+//
+// ip/basic_resolver_entry.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_BASIC_RESOLVER_ENTRY_HPP
+#define ASIO_IP_BASIC_RESOLVER_ENTRY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/string_view.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// An entry produced by a resolver.
+/**
+ * The asio::ip::basic_resolver_entry class template describes an entry
+ * as returned by a resolver.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename InternetProtocol>
+class basic_resolver_entry
+{
+public:
+  /// The protocol type associated with the endpoint entry.
+  typedef InternetProtocol protocol_type;
+
+  /// The endpoint type associated with the endpoint entry.
+  typedef typename InternetProtocol::endpoint endpoint_type;
+
+  /// Default constructor.
+  basic_resolver_entry()
+  {
+  }
+
+  /// Construct with specified endpoint, host name and service name.
+  basic_resolver_entry(const endpoint_type& ep,
+      ASIO_STRING_VIEW_PARAM host, ASIO_STRING_VIEW_PARAM service)
+    : endpoint_(ep),
+      host_name_(static_cast<std::string>(host)),
+      service_name_(static_cast<std::string>(service))
+  {
+  }
+
+  /// Get the endpoint associated with the entry.
+  endpoint_type endpoint() const
+  {
+    return endpoint_;
+  }
+
+  /// Convert to the endpoint associated with the entry.
+  operator endpoint_type() const
+  {
+    return endpoint_;
+  }
+
+  /// Get the host name associated with the entry.
+  std::string host_name() const
+  {
+    return host_name_;
+  }
+
+  /// Get the host name associated with the entry.
+  template <class Allocator>
+  std::basic_string<char, std::char_traits<char>, Allocator> host_name(
+      const Allocator& alloc = Allocator()) const
+  {
+    return std::basic_string<char, std::char_traits<char>, Allocator>(
+        host_name_.c_str(), alloc);
+  }
+
+  /// Get the service name associated with the entry.
+  std::string service_name() const
+  {
+    return service_name_;
+  }
+
+  /// Get the service name associated with the entry.
+  template <class Allocator>
+  std::basic_string<char, std::char_traits<char>, Allocator> service_name(
+      const Allocator& alloc = Allocator()) const
+  {
+    return std::basic_string<char, std::char_traits<char>, Allocator>(
+        service_name_.c_str(), alloc);
+  }
+
+private:
+  endpoint_type endpoint_;
+  std::string host_name_;
+  std::string service_name_;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_BASIC_RESOLVER_ENTRY_HPP
diff --git a/subprojects/asio/include/asio/ip/basic_resolver_iterator.hpp b/subprojects/asio/include/asio/ip/basic_resolver_iterator.hpp
new file mode 100644
index 000000000..ec5412cf6
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/basic_resolver_iterator.hpp
@@ -0,0 +1,192 @@
+//
+// ip/basic_resolver_iterator.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_BASIC_RESOLVER_ITERATOR_HPP
+#define ASIO_IP_BASIC_RESOLVER_ITERATOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <cstring>
+#include <iterator>
+#include <string>
+#include <vector>
+#include "asio/detail/memory.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/ip/basic_resolver_entry.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/winrt_utils.hpp"
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// An iterator over the entries produced by a resolver.
+/**
+ * The asio::ip::basic_resolver_iterator class template is used to define
+ * iterators over the results returned by a resolver.
+ *
+ * The iterator's value_type, obtained when the iterator is dereferenced, is:
+ * @code const basic_resolver_entry<InternetProtocol> @endcode
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename InternetProtocol>
+class basic_resolver_iterator
+{
+public:
+  /// The type used for the distance between two iterators.
+  typedef std::ptrdiff_t difference_type;
+
+  /// The type of the value pointed to by the iterator.
+  typedef basic_resolver_entry<InternetProtocol> value_type;
+
+  /// The type of the result of applying operator->() to the iterator.
+  typedef const basic_resolver_entry<InternetProtocol>* pointer;
+
+  /// The type of the result of applying operator*() to the iterator.
+  typedef const basic_resolver_entry<InternetProtocol>& reference;
+
+  /// The iterator category.
+  typedef std::forward_iterator_tag iterator_category;
+
+  /// Default constructor creates an end iterator.
+  basic_resolver_iterator()
+    : index_(0)
+  {
+  }
+
+  /// Copy constructor.
+  basic_resolver_iterator(const basic_resolver_iterator& other)
+    : values_(other.values_),
+      index_(other.index_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move constructor.
+  basic_resolver_iterator(basic_resolver_iterator&& other)
+    : values_(ASIO_MOVE_CAST(values_ptr_type)(other.values_)),
+      index_(other.index_)
+  {
+    other.index_ = 0;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Assignment operator.
+  basic_resolver_iterator& operator=(const basic_resolver_iterator& other)
+  {
+    values_ = other.values_;
+    index_ = other.index_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-assignment operator.
+  basic_resolver_iterator& operator=(basic_resolver_iterator&& other)
+  {
+    if (this != &other)
+    {
+      values_ = ASIO_MOVE_CAST(values_ptr_type)(other.values_);
+      index_ = other.index_;
+      other.index_ = 0;
+    }
+
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Dereference an iterator.
+  const basic_resolver_entry<InternetProtocol>& operator*() const
+  {
+    return dereference();
+  }
+
+  /// Dereference an iterator.
+  const basic_resolver_entry<InternetProtocol>* operator->() const
+  {
+    return &dereference();
+  }
+
+  /// Increment operator (prefix).
+  basic_resolver_iterator& operator++()
+  {
+    increment();
+    return *this;
+  }
+
+  /// Increment operator (postfix).
+  basic_resolver_iterator operator++(int)
+  {
+    basic_resolver_iterator tmp(*this);
+    ++*this;
+    return tmp;
+  }
+
+  /// Test two iterators for equality.
+  friend bool operator==(const basic_resolver_iterator& a,
+      const basic_resolver_iterator& b)
+  {
+    return a.equal(b);
+  }
+
+  /// Test two iterators for inequality.
+  friend bool operator!=(const basic_resolver_iterator& a,
+      const basic_resolver_iterator& b)
+  {
+    return !a.equal(b);
+  }
+
+protected:
+  void increment()
+  {
+    if (++index_ == values_->size())
+    {
+      // Reset state to match a default constructed end iterator.
+      values_.reset();
+      index_ = 0;
+    }
+  }
+
+  bool equal(const basic_resolver_iterator& other) const
+  {
+    if (!values_ && !other.values_)
+      return true;
+    if (values_ != other.values_)
+      return false;
+    return index_ == other.index_;
+  }
+
+  const basic_resolver_entry<InternetProtocol>& dereference() const
+  {
+    return (*values_)[index_];
+  }
+
+  typedef std::vector<basic_resolver_entry<InternetProtocol> > values_type;
+  typedef asio::detail::shared_ptr<values_type> values_ptr_type;
+  values_ptr_type values_;
+  std::size_t index_;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_BASIC_RESOLVER_ITERATOR_HPP
diff --git a/subprojects/asio/include/asio/ip/basic_resolver_query.hpp b/subprojects/asio/include/asio/ip/basic_resolver_query.hpp
new file mode 100644
index 000000000..84cd98d55
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/basic_resolver_query.hpp
@@ -0,0 +1,244 @@
+//
+// ip/basic_resolver_query.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_BASIC_RESOLVER_QUERY_HPP
+#define ASIO_IP_BASIC_RESOLVER_QUERY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/socket_ops.hpp"
+#include "asio/ip/resolver_query_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// An query to be passed to a resolver.
+/**
+ * The asio::ip::basic_resolver_query class template describes a query
+ * that can be passed to a resolver.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename InternetProtocol>
+class basic_resolver_query
+  : public resolver_query_base
+{
+public:
+  /// The protocol type associated with the endpoint query.
+  typedef InternetProtocol protocol_type;
+
+  /// Construct with specified service name for any protocol.
+  /**
+   * This constructor is typically used to perform name resolution for local
+   * service binding.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for local service
+   * binding.
+   *
+   * @note On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  basic_resolver_query(const std::string& service,
+      resolver_query_base::flags resolve_flags = passive | address_configured)
+    : hints_(),
+      host_name_(),
+      service_name_(service)
+  {
+    typename InternetProtocol::endpoint endpoint;
+    hints_.ai_flags = static_cast<int>(resolve_flags);
+    hints_.ai_family = PF_UNSPEC;
+    hints_.ai_socktype = endpoint.protocol().type();
+    hints_.ai_protocol = endpoint.protocol().protocol();
+    hints_.ai_addrlen = 0;
+    hints_.ai_canonname = 0;
+    hints_.ai_addr = 0;
+    hints_.ai_next = 0;
+  }
+
+  /// Construct with specified service name for a given protocol.
+  /**
+   * This constructor is typically used to perform name resolution for local
+   * service binding with a specific protocol version.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for local service
+   * binding.
+   *
+   * @note On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  basic_resolver_query(const protocol_type& protocol,
+      const std::string& service,
+      resolver_query_base::flags resolve_flags = passive | address_configured)
+    : hints_(),
+      host_name_(),
+      service_name_(service)
+  {
+    hints_.ai_flags = static_cast<int>(resolve_flags);
+    hints_.ai_family = protocol.family();
+    hints_.ai_socktype = protocol.type();
+    hints_.ai_protocol = protocol.protocol();
+    hints_.ai_addrlen = 0;
+    hints_.ai_canonname = 0;
+    hints_.ai_addr = 0;
+    hints_.ai_next = 0;
+  }
+
+  /// Construct with specified host name and service name for any protocol.
+  /**
+   * This constructor is typically used to perform name resolution for
+   * communication with remote hosts.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  basic_resolver_query(const std::string& host, const std::string& service,
+      resolver_query_base::flags resolve_flags = address_configured)
+    : hints_(),
+      host_name_(host),
+      service_name_(service)
+  {
+    typename InternetProtocol::endpoint endpoint;
+    hints_.ai_flags = static_cast<int>(resolve_flags);
+    hints_.ai_family = ASIO_OS_DEF(AF_UNSPEC);
+    hints_.ai_socktype = endpoint.protocol().type();
+    hints_.ai_protocol = endpoint.protocol().protocol();
+    hints_.ai_addrlen = 0;
+    hints_.ai_canonname = 0;
+    hints_.ai_addr = 0;
+    hints_.ai_next = 0;
+  }
+
+  /// Construct with specified host name and service name for a given protocol.
+  /**
+   * This constructor is typically used to perform name resolution for
+   * communication with remote hosts.
+   *
+   * @param protocol A protocol object, normally representing either the IPv4 or
+   * IPv6 version of an internet protocol.
+   *
+   * @param host A string identifying a location. May be a descriptive name or
+   * a numeric address string. If an empty string and the passive flag has been
+   * specified, the resolved endpoints are suitable for local service binding.
+   * If an empty string and passive is not specified, the resolved endpoints
+   * will use the loopback address.
+   *
+   * @param service A string identifying the requested service. This may be a
+   * descriptive name or a numeric string corresponding to a port number. May
+   * be an empty string, in which case all resolved endpoints will have a port
+   * number of 0.
+   *
+   * @param resolve_flags A set of flags that determine how name resolution
+   * should be performed. The default flags are suitable for communication with
+   * remote hosts.
+   *
+   * @note On POSIX systems, host names may be locally defined in the file
+   * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
+   * resolution is performed using DNS. Operating systems may use additional
+   * locations when resolving host names (such as NETBIOS names on Windows).
+   *
+   * On POSIX systems, service names are typically defined in the file
+   * <tt>/etc/services</tt>. On Windows, service names may be found in the file
+   * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
+   * may use additional locations when resolving service names.
+   */
+  basic_resolver_query(const protocol_type& protocol,
+      const std::string& host, const std::string& service,
+      resolver_query_base::flags resolve_flags = address_configured)
+    : hints_(),
+      host_name_(host),
+      service_name_(service)
+  {
+    hints_.ai_flags = static_cast<int>(resolve_flags);
+    hints_.ai_family = protocol.family();
+    hints_.ai_socktype = protocol.type();
+    hints_.ai_protocol = protocol.protocol();
+    hints_.ai_addrlen = 0;
+    hints_.ai_canonname = 0;
+    hints_.ai_addr = 0;
+    hints_.ai_next = 0;
+  }
+
+  /// Get the hints associated with the query.
+  const asio::detail::addrinfo_type& hints() const
+  {
+    return hints_;
+  }
+
+  /// Get the host name associated with the query.
+  std::string host_name() const
+  {
+    return host_name_;
+  }
+
+  /// Get the service name associated with the query.
+  std::string service_name() const
+  {
+    return service_name_;
+  }
+
+private:
+  asio::detail::addrinfo_type hints_;
+  std::string host_name_;
+  std::string service_name_;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_BASIC_RESOLVER_QUERY_HPP
diff --git a/subprojects/asio/include/asio/ip/basic_resolver_results.hpp b/subprojects/asio/include/asio/ip/basic_resolver_results.hpp
new file mode 100644
index 000000000..b87e33655
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/basic_resolver_results.hpp
@@ -0,0 +1,311 @@
+//
+// ip/basic_resolver_results.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_BASIC_RESOLVER_RESULTS_HPP
+#define ASIO_IP_BASIC_RESOLVER_RESULTS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <cstring>
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/winrt_utils.hpp"
+#endif // defined(ASIO_WINDOWS_RUNTIME)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// A range of entries produced by a resolver.
+/**
+ * The asio::ip::basic_resolver_results class template is used to define
+ * a range over the results returned by a resolver.
+ *
+ * The iterator's value_type, obtained when a results iterator is dereferenced,
+ * is: @code const basic_resolver_entry<InternetProtocol> @endcode
+ *
+ * @note For backward compatibility, basic_resolver_results is derived from
+ * basic_resolver_iterator. This derivation is deprecated.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename InternetProtocol>
+class basic_resolver_results
+#if !defined(ASIO_NO_DEPRECATED)
+  : public basic_resolver_iterator<InternetProtocol>
+#else // !defined(ASIO_NO_DEPRECATED)
+  : private basic_resolver_iterator<InternetProtocol>
+#endif // !defined(ASIO_NO_DEPRECATED)
+{
+public:
+  /// The protocol type associated with the results.
+  typedef InternetProtocol protocol_type;
+
+  /// The endpoint type associated with the results.
+  typedef typename protocol_type::endpoint endpoint_type;
+
+  /// The type of a value in the results range.
+  typedef basic_resolver_entry<protocol_type> value_type;
+
+  /// The type of a const reference to a value in the range.
+  typedef const value_type& const_reference;
+
+  /// The type of a non-const reference to a value in the range.
+  typedef value_type& reference;
+
+  /// The type of an iterator into the range.
+  typedef basic_resolver_iterator<protocol_type> const_iterator;
+
+  /// The type of an iterator into the range.
+  typedef const_iterator iterator;
+
+  /// Type used to represent the distance between two iterators in the range.
+  typedef std::ptrdiff_t difference_type;
+
+  /// Type used to represent a count of the elements in the range.
+  typedef std::size_t size_type;
+
+  /// Default constructor creates an empty range.
+  basic_resolver_results()
+  {
+  }
+
+  /// Copy constructor.
+  basic_resolver_results(const basic_resolver_results& other)
+    : basic_resolver_iterator<InternetProtocol>(other)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move constructor.
+  basic_resolver_results(basic_resolver_results&& other)
+    : basic_resolver_iterator<InternetProtocol>(
+        ASIO_MOVE_CAST(basic_resolver_results)(other))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Assignment operator.
+  basic_resolver_results& operator=(const basic_resolver_results& other)
+  {
+    basic_resolver_iterator<InternetProtocol>::operator=(other);
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-assignment operator.
+  basic_resolver_results& operator=(basic_resolver_results&& other)
+  {
+    basic_resolver_iterator<InternetProtocol>::operator=(
+        ASIO_MOVE_CAST(basic_resolver_results)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(GENERATING_DOCUMENTATION)
+  // Create results from an addrinfo list returned by getaddrinfo.
+  static basic_resolver_results create(
+      asio::detail::addrinfo_type* address_info,
+      const std::string& host_name, const std::string& service_name)
+  {
+    basic_resolver_results results;
+    if (!address_info)
+      return results;
+
+    std::string actual_host_name = host_name;
+    if (address_info->ai_canonname)
+      actual_host_name = address_info->ai_canonname;
+
+    results.values_.reset(new values_type);
+
+    while (address_info)
+    {
+      if (address_info->ai_family == ASIO_OS_DEF(AF_INET)
+          || address_info->ai_family == ASIO_OS_DEF(AF_INET6))
+      {
+        using namespace std; // For memcpy.
+        typename InternetProtocol::endpoint endpoint;
+        endpoint.resize(static_cast<std::size_t>(address_info->ai_addrlen));
+        memcpy(endpoint.data(), address_info->ai_addr,
+            address_info->ai_addrlen);
+        results.values_->push_back(
+            basic_resolver_entry<InternetProtocol>(endpoint,
+              actual_host_name, service_name));
+      }
+      address_info = address_info->ai_next;
+    }
+
+    return results;
+  }
+
+  // Create results from an endpoint, host name and service name.
+  static basic_resolver_results create(const endpoint_type& endpoint,
+      const std::string& host_name, const std::string& service_name)
+  {
+    basic_resolver_results results;
+    results.values_.reset(new values_type);
+    results.values_->push_back(
+        basic_resolver_entry<InternetProtocol>(
+          endpoint, host_name, service_name));
+    return results;
+  }
+
+  // Create results from a sequence of endpoints, host and service name.
+  template <typename EndpointIterator>
+  static basic_resolver_results create(
+      EndpointIterator begin, EndpointIterator end,
+      const std::string& host_name, const std::string& service_name)
+  {
+    basic_resolver_results results;
+    if (begin != end)
+    {
+      results.values_.reset(new values_type);
+      for (EndpointIterator ep_iter = begin; ep_iter != end; ++ep_iter)
+      {
+        results.values_->push_back(
+            basic_resolver_entry<InternetProtocol>(
+              *ep_iter, host_name, service_name));
+      }
+    }
+    return results;
+  }
+
+# if defined(ASIO_WINDOWS_RUNTIME)
+  // Create results from a Windows Runtime list of EndpointPair objects.
+  static basic_resolver_results create(
+      Windows::Foundation::Collections::IVectorView<
+        Windows::Networking::EndpointPair^>^ endpoints,
+      const asio::detail::addrinfo_type& hints,
+      const std::string& host_name, const std::string& service_name)
+  {
+    basic_resolver_results results;
+    if (endpoints->Size)
+    {
+      results.values_.reset(new values_type);
+      for (unsigned int i = 0; i < endpoints->Size; ++i)
+      {
+        auto pair = endpoints->GetAt(i);
+
+        if (hints.ai_family == ASIO_OS_DEF(AF_INET)
+            && pair->RemoteHostName->Type
+              != Windows::Networking::HostNameType::Ipv4)
+          continue;
+
+        if (hints.ai_family == ASIO_OS_DEF(AF_INET6)
+            && pair->RemoteHostName->Type
+              != Windows::Networking::HostNameType::Ipv6)
+          continue;
+
+        results.values_->push_back(
+            basic_resolver_entry<InternetProtocol>(
+              typename InternetProtocol::endpoint(
+                ip::make_address(
+                  asio::detail::winrt_utils::string(
+                    pair->RemoteHostName->CanonicalName)),
+                asio::detail::winrt_utils::integer(
+                  pair->RemoteServiceName)),
+              host_name, service_name));
+      }
+    }
+    return results;
+  }
+# endif // defined(ASIO_WINDOWS_RUNTIME)
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+  /// Get the number of entries in the results range.
+  size_type size() const ASIO_NOEXCEPT
+  {
+    return this->values_ ? this->values_->size() : 0;
+  }
+
+  /// Get the maximum number of entries permitted in a results range.
+  size_type max_size() const ASIO_NOEXCEPT
+  {
+    return this->values_ ? this->values_->max_size() : values_type().max_size();
+  }
+
+  /// Determine whether the results range is empty.
+  bool empty() const ASIO_NOEXCEPT
+  {
+    return this->values_ ? this->values_->empty() : true;
+  }
+
+  /// Obtain a begin iterator for the results range.
+  const_iterator begin() const
+  {
+    basic_resolver_results tmp(*this);
+    tmp.index_ = 0;
+    return ASIO_MOVE_CAST(basic_resolver_results)(tmp);
+  }
+
+  /// Obtain an end iterator for the results range.
+  const_iterator end() const
+  {
+    return const_iterator();
+  }
+
+  /// Obtain a begin iterator for the results range.
+  const_iterator cbegin() const
+  {
+    return begin();
+  }
+
+  /// Obtain an end iterator for the results range.
+  const_iterator cend() const
+  {
+    return end();
+  }
+
+  /// Swap the results range with another.
+  void swap(basic_resolver_results& that) ASIO_NOEXCEPT
+  {
+    if (this != &that)
+    {
+      this->values_.swap(that.values_);
+      std::size_t index = this->index_;
+      this->index_ = that.index_;
+      that.index_ = index;
+    }
+  }
+
+  /// Test two iterators for equality.
+  friend bool operator==(const basic_resolver_results& a,
+      const basic_resolver_results& b)
+  {
+    return a.equal(b);
+  }
+
+  /// Test two iterators for inequality.
+  friend bool operator!=(const basic_resolver_results& a,
+      const basic_resolver_results& b)
+  {
+    return !a.equal(b);
+  }
+
+private:
+  typedef std::vector<basic_resolver_entry<InternetProtocol> > values_type;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_BASIC_RESOLVER_RESULTS_HPP
diff --git a/subprojects/asio/include/asio/ip/detail/endpoint.hpp b/subprojects/asio/include/asio/ip/detail/endpoint.hpp
new file mode 100644
index 000000000..9acefe5fe
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/detail/endpoint.hpp
@@ -0,0 +1,139 @@
+//
+// ip/detail/endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_DETAIL_ENDPOINT_HPP
+#define ASIO_IP_DETAIL_ENDPOINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/winsock_init.hpp"
+#include "asio/error_code.hpp"
+#include "asio/ip/address.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+namespace detail {
+
+// Helper class for implementating an IP endpoint.
+class endpoint
+{
+public:
+  // Default constructor.
+  ASIO_DECL endpoint();
+
+  // Construct an endpoint using a family and port number.
+  ASIO_DECL endpoint(int family, unsigned short port_num);
+
+  // Construct an endpoint using an address and port number.
+  ASIO_DECL endpoint(const asio::ip::address& addr,
+      unsigned short port_num);
+
+  // Copy constructor.
+  endpoint(const endpoint& other)
+    : data_(other.data_)
+  {
+  }
+
+  // Assign from another endpoint.
+  endpoint& operator=(const endpoint& other)
+  {
+    data_ = other.data_;
+    return *this;
+  }
+
+  // Get the underlying endpoint in the native type.
+  asio::detail::socket_addr_type* data()
+  {
+    return &data_.base;
+  }
+
+  // Get the underlying endpoint in the native type.
+  const asio::detail::socket_addr_type* data() const
+  {
+    return &data_.base;
+  }
+
+  // Get the underlying size of the endpoint in the native type.
+  std::size_t size() const
+  {
+    if (is_v4())
+      return sizeof(asio::detail::sockaddr_in4_type);
+    else
+      return sizeof(asio::detail::sockaddr_in6_type);
+  }
+
+  // Set the underlying size of the endpoint in the native type.
+  ASIO_DECL void resize(std::size_t new_size);
+
+  // Get the capacity of the endpoint in the native type.
+  std::size_t capacity() const
+  {
+    return sizeof(data_);
+  }
+
+  // Get the port associated with the endpoint.
+  ASIO_DECL unsigned short port() const;
+
+  // Set the port associated with the endpoint.
+  ASIO_DECL void port(unsigned short port_num);
+
+  // Get the IP address associated with the endpoint.
+  ASIO_DECL asio::ip::address address() const;
+
+  // Set the IP address associated with the endpoint.
+  ASIO_DECL void address(const asio::ip::address& addr);
+
+  // Compare two endpoints for equality.
+  ASIO_DECL friend bool operator==(
+      const endpoint& e1, const endpoint& e2);
+
+  // Compare endpoints for ordering.
+  ASIO_DECL friend bool operator<(
+      const endpoint& e1, const endpoint& e2);
+
+  // Determine whether the endpoint is IPv4.
+  bool is_v4() const
+  {
+    return data_.base.sa_family == ASIO_OS_DEF(AF_INET);
+  }
+
+#if !defined(ASIO_NO_IOSTREAM)
+  // Convert to a string.
+  ASIO_DECL std::string to_string() const;
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+private:
+  // The underlying IP socket address.
+  union data_union
+  {
+    asio::detail::socket_addr_type base;
+    asio::detail::sockaddr_in4_type v4;
+    asio::detail::sockaddr_in6_type v6;
+  } data_;
+};
+
+} // namespace detail
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ip/detail/impl/endpoint.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_IP_DETAIL_ENDPOINT_HPP
diff --git a/subprojects/asio/include/asio/ip/detail/impl/endpoint.ipp b/subprojects/asio/include/asio/ip/detail/impl/endpoint.ipp
new file mode 100644
index 000000000..304bdf3d3
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/detail/impl/endpoint.ipp
@@ -0,0 +1,199 @@
+//
+// ip/detail/impl/endpoint.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_DETAIL_IMPL_ENDPOINT_IPP
+#define ASIO_IP_DETAIL_IMPL_ENDPOINT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstring>
+#if !defined(ASIO_NO_IOSTREAM)
+# include <sstream>
+#endif // !defined(ASIO_NO_IOSTREAM)
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/ip/detail/endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+namespace detail {
+
+endpoint::endpoint()
+  : data_()
+{
+  data_.v4.sin_family = ASIO_OS_DEF(AF_INET);
+  data_.v4.sin_port = 0;
+  data_.v4.sin_addr.s_addr = ASIO_OS_DEF(INADDR_ANY);
+}
+
+endpoint::endpoint(int family, unsigned short port_num)
+  : data_()
+{
+  using namespace std; // For memcpy.
+  if (family == ASIO_OS_DEF(AF_INET))
+  {
+    data_.v4.sin_family = ASIO_OS_DEF(AF_INET);
+    data_.v4.sin_port =
+      asio::detail::socket_ops::host_to_network_short(port_num);
+    data_.v4.sin_addr.s_addr = ASIO_OS_DEF(INADDR_ANY);
+  }
+  else
+  {
+    data_.v6.sin6_family = ASIO_OS_DEF(AF_INET6);
+    data_.v6.sin6_port =
+      asio::detail::socket_ops::host_to_network_short(port_num);
+    data_.v6.sin6_flowinfo = 0;
+    data_.v6.sin6_addr.s6_addr[0] = 0; data_.v6.sin6_addr.s6_addr[1] = 0;
+    data_.v6.sin6_addr.s6_addr[2] = 0; data_.v6.sin6_addr.s6_addr[3] = 0;
+    data_.v6.sin6_addr.s6_addr[4] = 0; data_.v6.sin6_addr.s6_addr[5] = 0;
+    data_.v6.sin6_addr.s6_addr[6] = 0; data_.v6.sin6_addr.s6_addr[7] = 0;
+    data_.v6.sin6_addr.s6_addr[8] = 0; data_.v6.sin6_addr.s6_addr[9] = 0;
+    data_.v6.sin6_addr.s6_addr[10] = 0; data_.v6.sin6_addr.s6_addr[11] = 0;
+    data_.v6.sin6_addr.s6_addr[12] = 0; data_.v6.sin6_addr.s6_addr[13] = 0;
+    data_.v6.sin6_addr.s6_addr[14] = 0; data_.v6.sin6_addr.s6_addr[15] = 0;
+    data_.v6.sin6_scope_id = 0;
+  }
+}
+
+endpoint::endpoint(const asio::ip::address& addr,
+    unsigned short port_num)
+  : data_()
+{
+  using namespace std; // For memcpy.
+  if (addr.is_v4())
+  {
+    data_.v4.sin_family = ASIO_OS_DEF(AF_INET);
+    data_.v4.sin_port =
+      asio::detail::socket_ops::host_to_network_short(port_num);
+    data_.v4.sin_addr.s_addr =
+      asio::detail::socket_ops::host_to_network_long(
+        addr.to_v4().to_uint());
+  }
+  else
+  {
+    data_.v6.sin6_family = ASIO_OS_DEF(AF_INET6);
+    data_.v6.sin6_port =
+      asio::detail::socket_ops::host_to_network_short(port_num);
+    data_.v6.sin6_flowinfo = 0;
+    asio::ip::address_v6 v6_addr = addr.to_v6();
+    asio::ip::address_v6::bytes_type bytes = v6_addr.to_bytes();
+    memcpy(data_.v6.sin6_addr.s6_addr, bytes.data(), 16);
+    data_.v6.sin6_scope_id =
+      static_cast<asio::detail::u_long_type>(
+        v6_addr.scope_id());
+  }
+}
+
+void endpoint::resize(std::size_t new_size)
+{
+  if (new_size > sizeof(asio::detail::sockaddr_storage_type))
+  {
+    asio::error_code ec(asio::error::invalid_argument);
+    asio::detail::throw_error(ec);
+  }
+}
+
+unsigned short endpoint::port() const
+{
+  if (is_v4())
+  {
+    return asio::detail::socket_ops::network_to_host_short(
+        data_.v4.sin_port);
+  }
+  else
+  {
+    return asio::detail::socket_ops::network_to_host_short(
+        data_.v6.sin6_port);
+  }
+}
+
+void endpoint::port(unsigned short port_num)
+{
+  if (is_v4())
+  {
+    data_.v4.sin_port
+      = asio::detail::socket_ops::host_to_network_short(port_num);
+  }
+  else
+  {
+    data_.v6.sin6_port
+      = asio::detail::socket_ops::host_to_network_short(port_num);
+  }
+}
+
+asio::ip::address endpoint::address() const
+{
+  using namespace std; // For memcpy.
+  if (is_v4())
+  {
+    return asio::ip::address_v4(
+        asio::detail::socket_ops::network_to_host_long(
+          data_.v4.sin_addr.s_addr));
+  }
+  else
+  {
+    asio::ip::address_v6::bytes_type bytes;
+#if defined(ASIO_HAS_STD_ARRAY)
+    memcpy(bytes.data(), data_.v6.sin6_addr.s6_addr, 16);
+#else // defined(ASIO_HAS_STD_ARRAY)
+    memcpy(bytes.elems, data_.v6.sin6_addr.s6_addr, 16);
+#endif // defined(ASIO_HAS_STD_ARRAY)
+    return asio::ip::address_v6(bytes, data_.v6.sin6_scope_id);
+  }
+}
+
+void endpoint::address(const asio::ip::address& addr)
+{
+  endpoint tmp_endpoint(addr, port());
+  data_ = tmp_endpoint.data_;
+}
+
+bool operator==(const endpoint& e1, const endpoint& e2)
+{
+  return e1.address() == e2.address() && e1.port() == e2.port();
+}
+
+bool operator<(const endpoint& e1, const endpoint& e2)
+{
+  if (e1.address() < e2.address())
+    return true;
+  if (e1.address() != e2.address())
+    return false;
+  return e1.port() < e2.port();
+}
+
+#if !defined(ASIO_NO_IOSTREAM)
+std::string endpoint::to_string() const
+{
+  std::ostringstream tmp_os;
+  tmp_os.imbue(std::locale::classic());
+  if (is_v4())
+    tmp_os << address();
+  else
+    tmp_os << '[' << address() << ']';
+  tmp_os << ':' << port();
+
+  return tmp_os.str();
+}
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+} // namespace detail
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_DETAIL_IMPL_ENDPOINT_IPP
diff --git a/subprojects/asio/include/asio/ip/detail/socket_option.hpp b/subprojects/asio/include/asio/ip/detail/socket_option.hpp
new file mode 100644
index 000000000..051ef30db
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/detail/socket_option.hpp
@@ -0,0 +1,566 @@
+//
+// detail/socket_option.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_DETAIL_SOCKET_OPTION_HPP
+#define ASIO_IP_DETAIL_SOCKET_OPTION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <cstring>
+#include <stdexcept>
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/ip/address.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+namespace detail {
+namespace socket_option {
+
+// Helper template for implementing multicast enable loopback options.
+template <int IPv4_Level, int IPv4_Name, int IPv6_Level, int IPv6_Name>
+class multicast_enable_loopback
+{
+public:
+#if defined(__sun) || defined(__osf__)
+  typedef unsigned char ipv4_value_type;
+  typedef unsigned char ipv6_value_type;
+#elif defined(_AIX) || defined(__hpux) || defined(__QNXNTO__) 
+  typedef unsigned char ipv4_value_type;
+  typedef unsigned int ipv6_value_type;
+#else
+  typedef int ipv4_value_type;
+  typedef int ipv6_value_type;
+#endif
+
+  // Default constructor.
+  multicast_enable_loopback()
+    : ipv4_value_(0),
+      ipv6_value_(0)
+  {
+  }
+
+  // Construct with a specific option value.
+  explicit multicast_enable_loopback(bool v)
+    : ipv4_value_(v ? 1 : 0),
+      ipv6_value_(v ? 1 : 0)
+  {
+  }
+
+  // Set the value of the boolean.
+  multicast_enable_loopback& operator=(bool v)
+  {
+    ipv4_value_ = v ? 1 : 0;
+    ipv6_value_ = v ? 1 : 0;
+    return *this;
+  }
+
+  // Get the current value of the boolean.
+  bool value() const
+  {
+    return !!ipv4_value_;
+  }
+
+  // Convert to bool.
+  operator bool() const
+  {
+    return !!ipv4_value_;
+  }
+
+  // Test for false.
+  bool operator!() const
+  {
+    return !ipv4_value_;
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Level;
+    return IPv4_Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Name;
+    return IPv4_Name;
+  }
+
+  // Get the address of the boolean data.
+  template <typename Protocol>
+  void* data(const Protocol& protocol)
+  {
+    if (protocol.family() == PF_INET6)
+      return &ipv6_value_;
+    return &ipv4_value_;
+  }
+
+  // Get the address of the boolean data.
+  template <typename Protocol>
+  const void* data(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return &ipv6_value_;
+    return &ipv4_value_;
+  }
+
+  // Get the size of the boolean data.
+  template <typename Protocol>
+  std::size_t size(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return sizeof(ipv6_value_);
+    return sizeof(ipv4_value_);
+  }
+
+  // Set the size of the boolean data.
+  template <typename Protocol>
+  void resize(const Protocol& protocol, std::size_t s)
+  {
+    if (protocol.family() == PF_INET6)
+    {
+      if (s != sizeof(ipv6_value_))
+      {
+        std::length_error ex("multicast_enable_loopback socket option resize");
+        asio::detail::throw_exception(ex);
+      }
+      ipv4_value_ = ipv6_value_ ? 1 : 0;
+    }
+    else
+    {
+      if (s != sizeof(ipv4_value_))
+      {
+        std::length_error ex("multicast_enable_loopback socket option resize");
+        asio::detail::throw_exception(ex);
+      }
+      ipv6_value_ = ipv4_value_ ? 1 : 0;
+    }
+  }
+
+private:
+  ipv4_value_type ipv4_value_;
+  ipv6_value_type ipv6_value_;
+};
+
+// Helper template for implementing unicast hops options.
+template <int IPv4_Level, int IPv4_Name, int IPv6_Level, int IPv6_Name>
+class unicast_hops
+{
+public:
+  // Default constructor.
+  unicast_hops()
+    : value_(0)
+  {
+  }
+
+  // Construct with a specific option value.
+  explicit unicast_hops(int v)
+    : value_(v)
+  {
+  }
+
+  // Set the value of the option.
+  unicast_hops& operator=(int v)
+  {
+    value_ = v;
+    return *this;
+  }
+
+  // Get the current value of the option.
+  int value() const
+  {
+    return value_;
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Level;
+    return IPv4_Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Name;
+    return IPv4_Name;
+  }
+
+  // Get the address of the data.
+  template <typename Protocol>
+  int* data(const Protocol&)
+  {
+    return &value_;
+  }
+
+  // Get the address of the data.
+  template <typename Protocol>
+  const int* data(const Protocol&) const
+  {
+    return &value_;
+  }
+
+  // Get the size of the data.
+  template <typename Protocol>
+  std::size_t size(const Protocol&) const
+  {
+    return sizeof(value_);
+  }
+
+  // Set the size of the data.
+  template <typename Protocol>
+  void resize(const Protocol&, std::size_t s)
+  {
+    if (s != sizeof(value_))
+    {
+      std::length_error ex("unicast hops socket option resize");
+      asio::detail::throw_exception(ex);
+    }
+#if defined(__hpux)
+    if (value_ < 0)
+      value_ = value_ & 0xFF;
+#endif
+  }
+
+private:
+  int value_;
+};
+
+// Helper template for implementing multicast hops options.
+template <int IPv4_Level, int IPv4_Name, int IPv6_Level, int IPv6_Name>
+class multicast_hops
+{
+public:
+#if defined(ASIO_WINDOWS) && defined(UNDER_CE)
+  typedef int ipv4_value_type;
+#else
+  typedef unsigned char ipv4_value_type;
+#endif
+  typedef int ipv6_value_type;
+
+  // Default constructor.
+  multicast_hops()
+    : ipv4_value_(0),
+      ipv6_value_(0)
+  {
+  }
+
+  // Construct with a specific option value.
+  explicit multicast_hops(int v)
+  {
+    if (v < 0 || v > 255)
+    {
+      std::out_of_range ex("multicast hops value out of range");
+      asio::detail::throw_exception(ex);
+    }
+    ipv4_value_ = (ipv4_value_type)v;
+    ipv6_value_ = v;
+  }
+
+  // Set the value of the option.
+  multicast_hops& operator=(int v)
+  {
+    if (v < 0 || v > 255)
+    {
+      std::out_of_range ex("multicast hops value out of range");
+      asio::detail::throw_exception(ex);
+    }
+    ipv4_value_ = (ipv4_value_type)v;
+    ipv6_value_ = v;
+    return *this;
+  }
+
+  // Get the current value of the option.
+  int value() const
+  {
+    return ipv6_value_;
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Level;
+    return IPv4_Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Name;
+    return IPv4_Name;
+  }
+
+  // Get the address of the data.
+  template <typename Protocol>
+  void* data(const Protocol& protocol)
+  {
+    if (protocol.family() == PF_INET6)
+      return &ipv6_value_;
+    return &ipv4_value_;
+  }
+
+  // Get the address of the data.
+  template <typename Protocol>
+  const void* data(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return &ipv6_value_;
+    return &ipv4_value_;
+  }
+
+  // Get the size of the data.
+  template <typename Protocol>
+  std::size_t size(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return sizeof(ipv6_value_);
+    return sizeof(ipv4_value_);
+  }
+
+  // Set the size of the data.
+  template <typename Protocol>
+  void resize(const Protocol& protocol, std::size_t s)
+  {
+    if (protocol.family() == PF_INET6)
+    {
+      if (s != sizeof(ipv6_value_))
+      {
+        std::length_error ex("multicast hops socket option resize");
+        asio::detail::throw_exception(ex);
+      }
+      if (ipv6_value_ < 0)
+        ipv4_value_ = 0;
+      else if (ipv6_value_ > 255)
+        ipv4_value_ = 255;
+      else
+        ipv4_value_ = (ipv4_value_type)ipv6_value_;
+    }
+    else
+    {
+      if (s != sizeof(ipv4_value_))
+      {
+        std::length_error ex("multicast hops socket option resize");
+        asio::detail::throw_exception(ex);
+      }
+      ipv6_value_ = ipv4_value_;
+    }
+  }
+
+private:
+  ipv4_value_type ipv4_value_;
+  ipv6_value_type ipv6_value_;
+};
+
+// Helper template for implementing ip_mreq-based options.
+template <int IPv4_Level, int IPv4_Name, int IPv6_Level, int IPv6_Name>
+class multicast_request
+{
+public:
+  // Default constructor.
+  multicast_request()
+    : ipv4_value_(), // Zero-initialisation gives the "any" address.
+      ipv6_value_() // Zero-initialisation gives the "any" address.
+  {
+  }
+
+  // Construct with multicast address only.
+  explicit multicast_request(const address& multicast_address)
+    : ipv4_value_(), // Zero-initialisation gives the "any" address.
+      ipv6_value_() // Zero-initialisation gives the "any" address.
+  {
+    if (multicast_address.is_v6())
+    {
+      using namespace std; // For memcpy.
+      address_v6 ipv6_address = multicast_address.to_v6();
+      address_v6::bytes_type bytes = ipv6_address.to_bytes();
+      memcpy(ipv6_value_.ipv6mr_multiaddr.s6_addr, bytes.data(), 16);
+      ipv6_value_.ipv6mr_interface = ipv6_address.scope_id();
+    }
+    else
+    {
+      ipv4_value_.imr_multiaddr.s_addr =
+        asio::detail::socket_ops::host_to_network_long(
+            multicast_address.to_v4().to_uint());
+      ipv4_value_.imr_interface.s_addr =
+        asio::detail::socket_ops::host_to_network_long(
+            address_v4::any().to_uint());
+    }
+  }
+
+  // Construct with multicast address and IPv4 address specifying an interface.
+  explicit multicast_request(const address_v4& multicast_address,
+      const address_v4& network_interface = address_v4::any())
+    : ipv6_value_() // Zero-initialisation gives the "any" address.
+  {
+    ipv4_value_.imr_multiaddr.s_addr =
+      asio::detail::socket_ops::host_to_network_long(
+          multicast_address.to_uint());
+    ipv4_value_.imr_interface.s_addr =
+      asio::detail::socket_ops::host_to_network_long(
+          network_interface.to_uint());
+  }
+
+  // Construct with multicast address and IPv6 network interface index.
+  explicit multicast_request(
+      const address_v6& multicast_address,
+      unsigned long network_interface = 0)
+    : ipv4_value_() // Zero-initialisation gives the "any" address.
+  {
+    using namespace std; // For memcpy.
+    address_v6::bytes_type bytes = multicast_address.to_bytes();
+    memcpy(ipv6_value_.ipv6mr_multiaddr.s6_addr, bytes.data(), 16);
+    if (network_interface)
+      ipv6_value_.ipv6mr_interface = network_interface;
+    else
+      ipv6_value_.ipv6mr_interface = multicast_address.scope_id();
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Level;
+    return IPv4_Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Name;
+    return IPv4_Name;
+  }
+
+  // Get the address of the option data.
+  template <typename Protocol>
+  const void* data(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return &ipv6_value_;
+    return &ipv4_value_;
+  }
+
+  // Get the size of the option data.
+  template <typename Protocol>
+  std::size_t size(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return sizeof(ipv6_value_);
+    return sizeof(ipv4_value_);
+  }
+
+private:
+  asio::detail::in4_mreq_type ipv4_value_;
+  asio::detail::in6_mreq_type ipv6_value_;
+};
+
+// Helper template for implementing options that specify a network interface.
+template <int IPv4_Level, int IPv4_Name, int IPv6_Level, int IPv6_Name>
+class network_interface
+{
+public:
+  // Default constructor.
+  network_interface()
+  {
+    ipv4_value_.s_addr =
+      asio::detail::socket_ops::host_to_network_long(
+          address_v4::any().to_uint());
+    ipv6_value_ = 0;
+  }
+
+  // Construct with IPv4 interface.
+  explicit network_interface(const address_v4& ipv4_interface)
+  {
+    ipv4_value_.s_addr =
+      asio::detail::socket_ops::host_to_network_long(
+          ipv4_interface.to_uint());
+    ipv6_value_ = 0;
+  }
+
+  // Construct with IPv6 interface.
+  explicit network_interface(unsigned int ipv6_interface)
+  {
+    ipv4_value_.s_addr =
+      asio::detail::socket_ops::host_to_network_long(
+          address_v4::any().to_uint());
+    ipv6_value_ = ipv6_interface;
+  }
+
+  // Get the level of the socket option.
+  template <typename Protocol>
+  int level(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Level;
+    return IPv4_Level;
+  }
+
+  // Get the name of the socket option.
+  template <typename Protocol>
+  int name(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return IPv6_Name;
+    return IPv4_Name;
+  }
+
+  // Get the address of the option data.
+  template <typename Protocol>
+  const void* data(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return &ipv6_value_;
+    return &ipv4_value_;
+  }
+
+  // Get the size of the option data.
+  template <typename Protocol>
+  std::size_t size(const Protocol& protocol) const
+  {
+    if (protocol.family() == PF_INET6)
+      return sizeof(ipv6_value_);
+    return sizeof(ipv4_value_);
+  }
+
+private:
+  asio::detail::in4_addr_type ipv4_value_;
+  unsigned int ipv6_value_;
+};
+
+} // namespace socket_option
+} // namespace detail
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_DETAIL_SOCKET_OPTION_HPP
diff --git a/subprojects/asio/include/asio/ip/host_name.hpp b/subprojects/asio/include/asio/ip/host_name.hpp
new file mode 100644
index 000000000..d06de5089
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/host_name.hpp
@@ -0,0 +1,42 @@
+//
+// ip/host_name.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_HOST_NAME_HPP
+#define ASIO_IP_HOST_NAME_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/error_code.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Get the current host name.
+ASIO_DECL std::string host_name();
+
+/// Get the current host name.
+ASIO_DECL std::string host_name(asio::error_code& ec);
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ip/impl/host_name.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_IP_HOST_NAME_HPP
diff --git a/subprojects/asio/include/asio/ip/icmp.hpp b/subprojects/asio/include/asio/ip/icmp.hpp
new file mode 100644
index 000000000..92e1953f3
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/icmp.hpp
@@ -0,0 +1,115 @@
+//
+// ip/icmp.hpp
+// ~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_ICMP_HPP
+#define ASIO_IP_ICMP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/basic_raw_socket.hpp"
+#include "asio/ip/basic_endpoint.hpp"
+#include "asio/ip/basic_resolver.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Encapsulates the flags needed for ICMP.
+/**
+ * The asio::ip::icmp class contains flags necessary for ICMP sockets.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol, InternetProtocol.
+ */
+class icmp
+{
+public:
+  /// The type of a ICMP endpoint.
+  typedef basic_endpoint<icmp> endpoint;
+
+  /// Construct to represent the IPv4 ICMP protocol.
+  static icmp v4()
+  {
+    return icmp(ASIO_OS_DEF(IPPROTO_ICMP),
+        ASIO_OS_DEF(AF_INET));
+  }
+
+  /// Construct to represent the IPv6 ICMP protocol.
+  static icmp v6()
+  {
+    return icmp(ASIO_OS_DEF(IPPROTO_ICMPV6),
+        ASIO_OS_DEF(AF_INET6));
+  }
+
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return ASIO_OS_DEF(SOCK_RAW);
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return protocol_;
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return family_;
+  }
+
+  /// The ICMP socket type.
+  typedef basic_raw_socket<icmp> socket;
+
+  /// The ICMP resolver type.
+  typedef basic_resolver<icmp> resolver;
+
+  /// Compare two protocols for equality.
+  friend bool operator==(const icmp& p1, const icmp& p2)
+  {
+    return p1.protocol_ == p2.protocol_ && p1.family_ == p2.family_;
+  }
+
+  /// Compare two protocols for inequality.
+  friend bool operator!=(const icmp& p1, const icmp& p2)
+  {
+    return p1.protocol_ != p2.protocol_ || p1.family_ != p2.family_;
+  }
+
+private:
+  // Construct with a specific family.
+  explicit icmp(int protocol_id, int protocol_family)
+    : protocol_(protocol_id),
+      family_(protocol_family)
+  {
+  }
+
+  int protocol_;
+  int family_;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_ICMP_HPP
diff --git a/subprojects/asio/include/asio/ip/impl/address.hpp b/subprojects/asio/include/asio/ip/impl/address.hpp
new file mode 100644
index 000000000..085b93f7b
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/address.hpp
@@ -0,0 +1,67 @@
+//
+// ip/impl/address.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_ADDRESS_HPP
+#define ASIO_IP_IMPL_ADDRESS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+inline address address::from_string(const char* str)
+{
+  return asio::ip::make_address(str);
+}
+
+inline address address::from_string(
+    const char* str, asio::error_code& ec)
+{
+  return asio::ip::make_address(str, ec);
+}
+
+inline address address::from_string(const std::string& str)
+{
+  return asio::ip::make_address(str);
+}
+
+inline address address::from_string(
+    const std::string& str, asio::error_code& ec)
+{
+  return asio::ip::make_address(str, ec);
+}
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const address& addr)
+{
+  return os << addr.to_string().c_str();
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_IP_IMPL_ADDRESS_HPP
diff --git a/subprojects/asio/include/asio/ip/impl/address.ipp b/subprojects/asio/include/asio/ip/impl/address.ipp
new file mode 100644
index 000000000..0523071fe
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/address.ipp
@@ -0,0 +1,234 @@
+//
+// ip/impl/address.ipp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_ADDRESS_IPP
+#define ASIO_IP_IMPL_ADDRESS_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <typeinfo>
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/error.hpp"
+#include "asio/ip/address.hpp"
+#include "asio/ip/bad_address_cast.hpp"
+#include "asio/system_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+address::address()
+  : type_(ipv4),
+    ipv4_address_(),
+    ipv6_address_()
+{
+}
+
+address::address(const asio::ip::address_v4& ipv4_address)
+  : type_(ipv4),
+    ipv4_address_(ipv4_address),
+    ipv6_address_()
+{
+}
+
+address::address(const asio::ip::address_v6& ipv6_address)
+  : type_(ipv6),
+    ipv4_address_(),
+    ipv6_address_(ipv6_address)
+{
+}
+
+address::address(const address& other)
+  : type_(other.type_),
+    ipv4_address_(other.ipv4_address_),
+    ipv6_address_(other.ipv6_address_)
+{
+}
+
+#if defined(ASIO_HAS_MOVE)
+address::address(address&& other)
+  : type_(other.type_),
+    ipv4_address_(other.ipv4_address_),
+    ipv6_address_(other.ipv6_address_)
+{
+}
+#endif // defined(ASIO_HAS_MOVE)
+
+address& address::operator=(const address& other)
+{
+  type_ = other.type_;
+  ipv4_address_ = other.ipv4_address_;
+  ipv6_address_ = other.ipv6_address_;
+  return *this;
+}
+
+#if defined(ASIO_HAS_MOVE)
+address& address::operator=(address&& other)
+{
+  type_ = other.type_;
+  ipv4_address_ = other.ipv4_address_;
+  ipv6_address_ = other.ipv6_address_;
+  return *this;
+}
+#endif // defined(ASIO_HAS_MOVE)
+
+address& address::operator=(const asio::ip::address_v4& ipv4_address)
+{
+  type_ = ipv4;
+  ipv4_address_ = ipv4_address;
+  ipv6_address_ = asio::ip::address_v6();
+  return *this;
+}
+
+address& address::operator=(const asio::ip::address_v6& ipv6_address)
+{
+  type_ = ipv6;
+  ipv4_address_ = asio::ip::address_v4();
+  ipv6_address_ = ipv6_address;
+  return *this;
+}
+
+address make_address(const char* str)
+{
+  asio::error_code ec;
+  address addr = make_address(str, ec);
+  asio::detail::throw_error(ec);
+  return addr;
+}
+
+address make_address(const char* str, asio::error_code& ec)
+{
+  asio::ip::address_v6 ipv6_address =
+    asio::ip::make_address_v6(str, ec);
+  if (!ec)
+    return address(ipv6_address);
+
+  asio::ip::address_v4 ipv4_address =
+    asio::ip::make_address_v4(str, ec);
+  if (!ec)
+    return address(ipv4_address);
+
+  return address();
+}
+
+address make_address(const std::string& str)
+{
+  return make_address(str.c_str());
+}
+
+address make_address(const std::string& str,
+    asio::error_code& ec)
+{
+  return make_address(str.c_str(), ec);
+}
+
+#if defined(ASIO_HAS_STRING_VIEW)
+
+address make_address(string_view str)
+{
+  return make_address(static_cast<std::string>(str));
+}
+
+address make_address(string_view str,
+    asio::error_code& ec)
+{
+  return make_address(static_cast<std::string>(str), ec);
+}
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+
+asio::ip::address_v4 address::to_v4() const
+{
+  if (type_ != ipv4)
+  {
+    bad_address_cast ex;
+    asio::detail::throw_exception(ex);
+  }
+  return ipv4_address_;
+}
+
+asio::ip::address_v6 address::to_v6() const
+{
+  if (type_ != ipv6)
+  {
+    bad_address_cast ex;
+    asio::detail::throw_exception(ex);
+  }
+  return ipv6_address_;
+}
+
+std::string address::to_string() const
+{
+  if (type_ == ipv6)
+    return ipv6_address_.to_string();
+  return ipv4_address_.to_string();
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+std::string address::to_string(asio::error_code& ec) const
+{
+  if (type_ == ipv6)
+    return ipv6_address_.to_string(ec);
+  return ipv4_address_.to_string(ec);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+bool address::is_loopback() const
+{
+  return (type_ == ipv4)
+    ? ipv4_address_.is_loopback()
+    : ipv6_address_.is_loopback();
+}
+
+bool address::is_unspecified() const
+{
+  return (type_ == ipv4)
+    ? ipv4_address_.is_unspecified()
+    : ipv6_address_.is_unspecified();
+}
+
+bool address::is_multicast() const
+{
+  return (type_ == ipv4)
+    ? ipv4_address_.is_multicast()
+    : ipv6_address_.is_multicast();
+}
+
+bool operator==(const address& a1, const address& a2)
+{
+  if (a1.type_ != a2.type_)
+    return false;
+  if (a1.type_ == address::ipv6)
+    return a1.ipv6_address_ == a2.ipv6_address_;
+  return a1.ipv4_address_ == a2.ipv4_address_;
+}
+
+bool operator<(const address& a1, const address& a2)
+{
+  if (a1.type_ < a2.type_)
+    return true;
+  if (a1.type_ > a2.type_)
+    return false;
+  if (a1.type_ == address::ipv6)
+    return a1.ipv6_address_ < a2.ipv6_address_;
+  return a1.ipv4_address_ < a2.ipv4_address_;
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_IMPL_ADDRESS_IPP
diff --git a/subprojects/asio/include/asio/ip/impl/address_v4.hpp b/subprojects/asio/include/asio/ip/impl/address_v4.hpp
new file mode 100644
index 000000000..d1cf407c3
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/address_v4.hpp
@@ -0,0 +1,67 @@
+//
+// ip/impl/address_v4.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_ADDRESS_V4_HPP
+#define ASIO_IP_IMPL_ADDRESS_V4_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+inline address_v4 address_v4::from_string(const char* str)
+{
+  return asio::ip::make_address_v4(str);
+}
+
+inline address_v4 address_v4::from_string(
+    const char* str, asio::error_code& ec)
+{
+  return asio::ip::make_address_v4(str, ec);
+}
+
+inline address_v4 address_v4::from_string(const std::string& str)
+{
+  return asio::ip::make_address_v4(str);
+}
+
+inline address_v4 address_v4::from_string(
+    const std::string& str, asio::error_code& ec)
+{
+  return asio::ip::make_address_v4(str, ec);
+}
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const address_v4& addr)
+{
+  return os << addr.to_string().c_str();
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_IP_IMPL_ADDRESS_V4_HPP
diff --git a/subprojects/asio/include/asio/ip/impl/address_v4.ipp b/subprojects/asio/include/asio/ip/impl/address_v4.ipp
new file mode 100644
index 000000000..9559addb6
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/address_v4.ipp
@@ -0,0 +1,210 @@
+//
+// ip/impl/address_v4.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_ADDRESS_V4_IPP
+#define ASIO_IP_IMPL_ADDRESS_V4_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <climits>
+#include <limits>
+#include <stdexcept>
+#include "asio/error.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/ip/address_v4.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+address_v4::address_v4(const address_v4::bytes_type& bytes)
+{
+#if UCHAR_MAX > 0xFF
+  if (bytes[0] > 0xFF || bytes[1] > 0xFF
+      || bytes[2] > 0xFF || bytes[3] > 0xFF)
+  {
+    std::out_of_range ex("address_v4 from bytes_type");
+    asio::detail::throw_exception(ex);
+  }
+#endif // UCHAR_MAX > 0xFF
+
+  using namespace std; // For memcpy.
+  memcpy(&addr_.s_addr, bytes.data(), 4);
+}
+
+address_v4::address_v4(address_v4::uint_type addr)
+{
+  if ((std::numeric_limits<uint_type>::max)() > 0xFFFFFFFF)
+  {
+    std::out_of_range ex("address_v4 from unsigned integer");
+    asio::detail::throw_exception(ex);
+  }
+
+  addr_.s_addr = asio::detail::socket_ops::host_to_network_long(
+      static_cast<asio::detail::u_long_type>(addr));
+}
+
+address_v4::bytes_type address_v4::to_bytes() const
+{
+  using namespace std; // For memcpy.
+  bytes_type bytes;
+#if defined(ASIO_HAS_STD_ARRAY)
+  memcpy(bytes.data(), &addr_.s_addr, 4);
+#else // defined(ASIO_HAS_STD_ARRAY)
+  memcpy(bytes.elems, &addr_.s_addr, 4);
+#endif // defined(ASIO_HAS_STD_ARRAY)
+  return bytes;
+}
+
+address_v4::uint_type address_v4::to_uint() const
+{
+  return asio::detail::socket_ops::network_to_host_long(addr_.s_addr);
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+unsigned long address_v4::to_ulong() const
+{
+  return asio::detail::socket_ops::network_to_host_long(addr_.s_addr);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+std::string address_v4::to_string() const
+{
+  asio::error_code ec;
+  char addr_str[asio::detail::max_addr_v4_str_len];
+  const char* addr =
+    asio::detail::socket_ops::inet_ntop(
+        ASIO_OS_DEF(AF_INET), &addr_, addr_str,
+        asio::detail::max_addr_v4_str_len, 0, ec);
+  if (addr == 0)
+    asio::detail::throw_error(ec);
+  return addr;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+std::string address_v4::to_string(asio::error_code& ec) const
+{
+  char addr_str[asio::detail::max_addr_v4_str_len];
+  const char* addr =
+    asio::detail::socket_ops::inet_ntop(
+        ASIO_OS_DEF(AF_INET), &addr_, addr_str,
+        asio::detail::max_addr_v4_str_len, 0, ec);
+  if (addr == 0)
+    return std::string();
+  return addr;
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+bool address_v4::is_loopback() const
+{
+  return (to_uint() & 0xFF000000) == 0x7F000000;
+}
+
+bool address_v4::is_unspecified() const
+{
+  return to_uint() == 0;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+bool address_v4::is_class_a() const
+{
+  return (to_uint() & 0x80000000) == 0;
+}
+
+bool address_v4::is_class_b() const
+{
+  return (to_uint() & 0xC0000000) == 0x80000000;
+}
+
+bool address_v4::is_class_c() const
+{
+  return (to_uint() & 0xE0000000) == 0xC0000000;
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+bool address_v4::is_multicast() const
+{
+  return (to_uint() & 0xF0000000) == 0xE0000000;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+address_v4 address_v4::broadcast(const address_v4& addr, const address_v4& mask)
+{
+  return address_v4(addr.to_uint() | (mask.to_uint() ^ 0xFFFFFFFF));
+}
+
+address_v4 address_v4::netmask(const address_v4& addr)
+{
+  if (addr.is_class_a())
+    return address_v4(0xFF000000);
+  if (addr.is_class_b())
+    return address_v4(0xFFFF0000);
+  if (addr.is_class_c())
+    return address_v4(0xFFFFFF00);
+  return address_v4(0xFFFFFFFF);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+address_v4 make_address_v4(const char* str)
+{
+  asio::error_code ec;
+  address_v4 addr = make_address_v4(str, ec);
+  asio::detail::throw_error(ec);
+  return addr;
+}
+
+address_v4 make_address_v4(
+    const char* str, asio::error_code& ec)
+{
+  address_v4::bytes_type bytes;
+  if (asio::detail::socket_ops::inet_pton(
+        ASIO_OS_DEF(AF_INET), str, &bytes, 0, ec) <= 0)
+    return address_v4();
+  return address_v4(bytes);
+}
+
+address_v4 make_address_v4(const std::string& str)
+{
+  return make_address_v4(str.c_str());
+}
+
+address_v4 make_address_v4(
+    const std::string& str, asio::error_code& ec)
+{
+  return make_address_v4(str.c_str(), ec);
+}
+
+#if defined(ASIO_HAS_STRING_VIEW)
+
+address_v4 make_address_v4(string_view str)
+{
+  return make_address_v4(static_cast<std::string>(str));
+}
+
+address_v4 make_address_v4(string_view str,
+    asio::error_code& ec)
+{
+  return make_address_v4(static_cast<std::string>(str), ec);
+}
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_IMPL_ADDRESS_V4_IPP
diff --git a/subprojects/asio/include/asio/ip/impl/address_v6.hpp b/subprojects/asio/include/asio/ip/impl/address_v6.hpp
new file mode 100644
index 000000000..330eafd1f
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/address_v6.hpp
@@ -0,0 +1,67 @@
+//
+// ip/impl/address_v6.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_ADDRESS_V6_HPP
+#define ASIO_IP_IMPL_ADDRESS_V6_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+#if !defined(ASIO_NO_DEPRECATED)
+
+inline address_v6 address_v6::from_string(const char* str)
+{
+  return asio::ip::make_address_v6(str);
+}
+
+inline address_v6 address_v6::from_string(
+    const char* str, asio::error_code& ec)
+{
+  return asio::ip::make_address_v6(str, ec);
+}
+
+inline address_v6 address_v6::from_string(const std::string& str)
+{
+  return asio::ip::make_address_v6(str);
+}
+
+inline address_v6 address_v6::from_string(
+    const std::string& str, asio::error_code& ec)
+{
+  return asio::ip::make_address_v6(str, ec);
+}
+
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const address_v6& addr)
+{
+  return os << addr.to_string().c_str();
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_IP_IMPL_ADDRESS_V6_HPP
diff --git a/subprojects/asio/include/asio/ip/impl/address_v6.ipp b/subprojects/asio/include/asio/ip/impl/address_v6.ipp
new file mode 100644
index 000000000..36bd68cff
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/address_v6.ipp
@@ -0,0 +1,350 @@
+//
+// ip/impl/address_v6.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_ADDRESS_V6_IPP
+#define ASIO_IP_IMPL_ADDRESS_V6_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstring>
+#include <stdexcept>
+#include <typeinfo>
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/error.hpp"
+#include "asio/ip/address_v6.hpp"
+#include "asio/ip/bad_address_cast.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+address_v6::address_v6()
+  : addr_(),
+    scope_id_(0)
+{
+}
+
+address_v6::address_v6(const address_v6::bytes_type& bytes,
+    unsigned long scope)
+  : scope_id_(scope)
+{
+#if UCHAR_MAX > 0xFF
+  for (std::size_t i = 0; i < bytes.size(); ++i)
+  {
+    if (bytes[i] > 0xFF)
+    {
+      std::out_of_range ex("address_v6 from bytes_type");
+      asio::detail::throw_exception(ex);
+    }
+  }
+#endif // UCHAR_MAX > 0xFF
+
+  using namespace std; // For memcpy.
+  memcpy(addr_.s6_addr, bytes.data(), 16);
+}
+
+address_v6::address_v6(const address_v6& other)
+  : addr_(other.addr_),
+    scope_id_(other.scope_id_)
+{
+}
+
+#if defined(ASIO_HAS_MOVE)
+address_v6::address_v6(address_v6&& other)
+  : addr_(other.addr_),
+    scope_id_(other.scope_id_)
+{
+}
+#endif // defined(ASIO_HAS_MOVE)
+
+address_v6& address_v6::operator=(const address_v6& other)
+{
+  addr_ = other.addr_;
+  scope_id_ = other.scope_id_;
+  return *this;
+}
+
+#if defined(ASIO_HAS_MOVE)
+address_v6& address_v6::operator=(address_v6&& other)
+{
+  addr_ = other.addr_;
+  scope_id_ = other.scope_id_;
+  return *this;
+}
+#endif // defined(ASIO_HAS_MOVE)
+
+address_v6::bytes_type address_v6::to_bytes() const
+{
+  using namespace std; // For memcpy.
+  bytes_type bytes;
+#if defined(ASIO_HAS_STD_ARRAY)
+  memcpy(bytes.data(), addr_.s6_addr, 16);
+#else // defined(ASIO_HAS_STD_ARRAY)
+  memcpy(bytes.elems, addr_.s6_addr, 16);
+#endif // defined(ASIO_HAS_STD_ARRAY)
+  return bytes;
+}
+
+std::string address_v6::to_string() const
+{
+  asio::error_code ec;
+  char addr_str[asio::detail::max_addr_v6_str_len];
+  const char* addr =
+    asio::detail::socket_ops::inet_ntop(
+        ASIO_OS_DEF(AF_INET6), &addr_, addr_str,
+        asio::detail::max_addr_v6_str_len, scope_id_, ec);
+  if (addr == 0)
+    asio::detail::throw_error(ec);
+  return addr;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+std::string address_v6::to_string(asio::error_code& ec) const
+{
+  char addr_str[asio::detail::max_addr_v6_str_len];
+  const char* addr =
+    asio::detail::socket_ops::inet_ntop(
+        ASIO_OS_DEF(AF_INET6), &addr_, addr_str,
+        asio::detail::max_addr_v6_str_len, scope_id_, ec);
+  if (addr == 0)
+    return std::string();
+  return addr;
+}
+
+address_v4 address_v6::to_v4() const
+{
+  if (!is_v4_mapped() && !is_v4_compatible())
+  {
+    bad_address_cast ex;
+    asio::detail::throw_exception(ex);
+  }
+
+  address_v4::bytes_type v4_bytes = { { addr_.s6_addr[12],
+    addr_.s6_addr[13], addr_.s6_addr[14], addr_.s6_addr[15] } };
+  return address_v4(v4_bytes);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+bool address_v6::is_loopback() const
+{
+  return ((addr_.s6_addr[0] == 0) && (addr_.s6_addr[1] == 0)
+      && (addr_.s6_addr[2] == 0) && (addr_.s6_addr[3] == 0)
+      && (addr_.s6_addr[4] == 0) && (addr_.s6_addr[5] == 0)
+      && (addr_.s6_addr[6] == 0) && (addr_.s6_addr[7] == 0)
+      && (addr_.s6_addr[8] == 0) && (addr_.s6_addr[9] == 0)
+      && (addr_.s6_addr[10] == 0) && (addr_.s6_addr[11] == 0)
+      && (addr_.s6_addr[12] == 0) && (addr_.s6_addr[13] == 0)
+      && (addr_.s6_addr[14] == 0) && (addr_.s6_addr[15] == 1));
+}
+
+bool address_v6::is_unspecified() const
+{
+  return ((addr_.s6_addr[0] == 0) && (addr_.s6_addr[1] == 0)
+      && (addr_.s6_addr[2] == 0) && (addr_.s6_addr[3] == 0)
+      && (addr_.s6_addr[4] == 0) && (addr_.s6_addr[5] == 0)
+      && (addr_.s6_addr[6] == 0) && (addr_.s6_addr[7] == 0)
+      && (addr_.s6_addr[8] == 0) && (addr_.s6_addr[9] == 0)
+      && (addr_.s6_addr[10] == 0) && (addr_.s6_addr[11] == 0)
+      && (addr_.s6_addr[12] == 0) && (addr_.s6_addr[13] == 0)
+      && (addr_.s6_addr[14] == 0) && (addr_.s6_addr[15] == 0));
+}
+
+bool address_v6::is_link_local() const
+{
+  return ((addr_.s6_addr[0] == 0xfe) && ((addr_.s6_addr[1] & 0xc0) == 0x80));
+}
+
+bool address_v6::is_site_local() const
+{
+  return ((addr_.s6_addr[0] == 0xfe) && ((addr_.s6_addr[1] & 0xc0) == 0xc0));
+}
+
+bool address_v6::is_v4_mapped() const
+{
+  return ((addr_.s6_addr[0] == 0) && (addr_.s6_addr[1] == 0)
+      && (addr_.s6_addr[2] == 0) && (addr_.s6_addr[3] == 0)
+      && (addr_.s6_addr[4] == 0) && (addr_.s6_addr[5] == 0)
+      && (addr_.s6_addr[6] == 0) && (addr_.s6_addr[7] == 0)
+      && (addr_.s6_addr[8] == 0) && (addr_.s6_addr[9] == 0)
+      && (addr_.s6_addr[10] == 0xff) && (addr_.s6_addr[11] == 0xff));
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+bool address_v6::is_v4_compatible() const
+{
+  return ((addr_.s6_addr[0] == 0) && (addr_.s6_addr[1] == 0)
+      && (addr_.s6_addr[2] == 0) && (addr_.s6_addr[3] == 0)
+      && (addr_.s6_addr[4] == 0) && (addr_.s6_addr[5] == 0)
+      && (addr_.s6_addr[6] == 0) && (addr_.s6_addr[7] == 0)
+      && (addr_.s6_addr[8] == 0) && (addr_.s6_addr[9] == 0)
+      && (addr_.s6_addr[10] == 0) && (addr_.s6_addr[11] == 0)
+      && !((addr_.s6_addr[12] == 0)
+        && (addr_.s6_addr[13] == 0)
+        && (addr_.s6_addr[14] == 0)
+        && ((addr_.s6_addr[15] == 0) || (addr_.s6_addr[15] == 1))));
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+bool address_v6::is_multicast() const
+{
+  return (addr_.s6_addr[0] == 0xff);
+}
+
+bool address_v6::is_multicast_global() const
+{
+  return ((addr_.s6_addr[0] == 0xff) && ((addr_.s6_addr[1] & 0x0f) == 0x0e));
+}
+
+bool address_v6::is_multicast_link_local() const
+{
+  return ((addr_.s6_addr[0] == 0xff) && ((addr_.s6_addr[1] & 0x0f) == 0x02));
+}
+
+bool address_v6::is_multicast_node_local() const
+{
+  return ((addr_.s6_addr[0] == 0xff) && ((addr_.s6_addr[1] & 0x0f) == 0x01));
+}
+
+bool address_v6::is_multicast_org_local() const
+{
+  return ((addr_.s6_addr[0] == 0xff) && ((addr_.s6_addr[1] & 0x0f) == 0x08));
+}
+
+bool address_v6::is_multicast_site_local() const
+{
+  return ((addr_.s6_addr[0] == 0xff) && ((addr_.s6_addr[1] & 0x0f) == 0x05));
+}
+
+bool operator==(const address_v6& a1, const address_v6& a2)
+{
+  using namespace std; // For memcmp.
+  return memcmp(&a1.addr_, &a2.addr_,
+      sizeof(asio::detail::in6_addr_type)) == 0
+    && a1.scope_id_ == a2.scope_id_;
+}
+
+bool operator<(const address_v6& a1, const address_v6& a2)
+{
+  using namespace std; // For memcmp.
+  int memcmp_result = memcmp(&a1.addr_, &a2.addr_,
+      sizeof(asio::detail::in6_addr_type));
+  if (memcmp_result < 0)
+    return true;
+  if (memcmp_result > 0)
+    return false;
+  return a1.scope_id_ < a2.scope_id_;
+}
+
+address_v6 address_v6::loopback()
+{
+  address_v6 tmp;
+  tmp.addr_.s6_addr[15] = 1;
+  return tmp;
+}
+
+#if !defined(ASIO_NO_DEPRECATED)
+address_v6 address_v6::v4_mapped(const address_v4& addr)
+{
+  address_v4::bytes_type v4_bytes = addr.to_bytes();
+  bytes_type v6_bytes = { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF,
+    v4_bytes[0], v4_bytes[1], v4_bytes[2], v4_bytes[3] } };
+  return address_v6(v6_bytes);
+}
+
+address_v6 address_v6::v4_compatible(const address_v4& addr)
+{
+  address_v4::bytes_type v4_bytes = addr.to_bytes();
+  bytes_type v6_bytes = { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    v4_bytes[0], v4_bytes[1], v4_bytes[2], v4_bytes[3] } };
+  return address_v6(v6_bytes);
+}
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+address_v6 make_address_v6(const char* str)
+{
+  asio::error_code ec;
+  address_v6 addr = make_address_v6(str, ec);
+  asio::detail::throw_error(ec);
+  return addr;
+}
+
+address_v6 make_address_v6(
+    const char* str, asio::error_code& ec)
+{
+  address_v6::bytes_type bytes;
+  unsigned long scope_id = 0;
+  if (asio::detail::socket_ops::inet_pton(
+        ASIO_OS_DEF(AF_INET6), str, &bytes[0], &scope_id, ec) <= 0)
+    return address_v6();
+  return address_v6(bytes, scope_id);
+}
+
+address_v6 make_address_v6(const std::string& str)
+{
+  return make_address_v6(str.c_str());
+}
+
+address_v6 make_address_v6(
+    const std::string& str, asio::error_code& ec)
+{
+  return make_address_v6(str.c_str(), ec);
+}
+
+#if defined(ASIO_HAS_STRING_VIEW)
+
+address_v6 make_address_v6(string_view str)
+{
+  return make_address_v6(static_cast<std::string>(str));
+}
+
+address_v6 make_address_v6(string_view str,
+    asio::error_code& ec)
+{
+  return make_address_v6(static_cast<std::string>(str), ec);
+}
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+
+address_v4 make_address_v4(
+    v4_mapped_t, const address_v6& v6_addr)
+{
+  if (!v6_addr.is_v4_mapped())
+  {
+    bad_address_cast ex;
+    asio::detail::throw_exception(ex);
+  }
+
+  address_v6::bytes_type v6_bytes = v6_addr.to_bytes();
+  address_v4::bytes_type v4_bytes = { { v6_bytes[12],
+    v6_bytes[13], v6_bytes[14], v6_bytes[15] } };
+  return address_v4(v4_bytes);
+}
+
+address_v6 make_address_v6(
+    v4_mapped_t, const address_v4& v4_addr)
+{
+  address_v4::bytes_type v4_bytes = v4_addr.to_bytes();
+  address_v6::bytes_type v6_bytes = { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0xFF, 0xFF, v4_bytes[0], v4_bytes[1], v4_bytes[2], v4_bytes[3] } };
+  return address_v6(v6_bytes);
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_IMPL_ADDRESS_V6_IPP
diff --git a/subprojects/asio/include/asio/ip/impl/basic_endpoint.hpp b/subprojects/asio/include/asio/ip/impl/basic_endpoint.hpp
new file mode 100644
index 000000000..5680a4381
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/basic_endpoint.hpp
@@ -0,0 +1,43 @@
+//
+// ip/impl/basic_endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_BASIC_ENDPOINT_HPP
+#define ASIO_IP_IMPL_BASIC_ENDPOINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename Elem, typename Traits, typename InternetProtocol>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os,
+    const basic_endpoint<InternetProtocol>& endpoint)
+{
+  asio::ip::detail::endpoint tmp_ep(endpoint.address(), endpoint.port());
+  return os << tmp_ep.to_string().c_str();
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_IP_IMPL_BASIC_ENDPOINT_HPP
diff --git a/subprojects/asio/include/asio/ip/impl/host_name.ipp b/subprojects/asio/include/asio/ip/impl/host_name.ipp
new file mode 100644
index 000000000..932ab1c6d
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/host_name.ipp
@@ -0,0 +1,54 @@
+//
+// ip/impl/host_name.ipp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_HOST_NAME_IPP
+#define ASIO_IP_IMPL_HOST_NAME_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/winsock_init.hpp"
+#include "asio/ip/host_name.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+std::string host_name()
+{
+  char name[1024];
+  asio::error_code ec;
+  if (asio::detail::socket_ops::gethostname(name, sizeof(name), ec) != 0)
+  {
+    asio::detail::throw_error(ec);
+    return std::string();
+  }
+  return std::string(name);
+}
+
+std::string host_name(asio::error_code& ec)
+{
+  char name[1024];
+  if (asio::detail::socket_ops::gethostname(name, sizeof(name), ec) != 0)
+    return std::string();
+  return std::string(name);
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_IMPL_HOST_NAME_IPP
diff --git a/subprojects/asio/include/asio/ip/impl/network_v4.hpp b/subprojects/asio/include/asio/ip/impl/network_v4.hpp
new file mode 100644
index 000000000..911a45c3f
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/network_v4.hpp
@@ -0,0 +1,54 @@
+//
+// ip/impl/network_v4.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2014 Oliver Kowalke (oliver dot kowalke at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_NETWORK_V4_HPP
+#define ASIO_IP_IMPL_NETWORK_V4_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const network_v4& addr)
+{
+  asio::error_code ec;
+  std::string s = addr.to_string(ec);
+  if (ec)
+  {
+    if (os.exceptions() & std::basic_ostream<Elem, Traits>::failbit)
+      asio::detail::throw_error(ec);
+    else
+      os.setstate(std::basic_ostream<Elem, Traits>::failbit);
+  }
+  else
+    for (std::string::iterator i = s.begin(); i != s.end(); ++i)
+      os << os.widen(*i);
+  return os;
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_IP_IMPL_NETWORK_V4_HPP
diff --git a/subprojects/asio/include/asio/ip/impl/network_v4.ipp b/subprojects/asio/include/asio/ip/impl/network_v4.ipp
new file mode 100644
index 000000000..4b278871b
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/network_v4.ipp
@@ -0,0 +1,216 @@
+//
+// ip/impl/network_v4.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2014 Oliver Kowalke (oliver dot kowalke at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_NETWORK_V4_IPP
+#define ASIO_IP_IMPL_NETWORK_V4_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <climits>
+#include <cstdio>
+#include <cstdlib>
+#include <stdexcept>
+#include "asio/error.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/ip/network_v4.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+network_v4::network_v4(const address_v4& addr, unsigned short prefix_len)
+  : address_(addr),
+    prefix_length_(prefix_len)
+{
+  if (prefix_len > 32)
+  {
+    std::out_of_range ex("prefix length too large");
+    asio::detail::throw_exception(ex);
+  }
+}
+
+network_v4::network_v4(const address_v4& addr, const address_v4& mask)
+  : address_(addr),
+    prefix_length_(0)
+{
+  address_v4::bytes_type mask_bytes = mask.to_bytes();
+  bool finished = false;
+  for (std::size_t i = 0; i < mask_bytes.size(); ++i)
+  {
+    if (finished)
+    {
+      if (mask_bytes[i])
+      {
+        std::invalid_argument ex("non-contiguous netmask");
+        asio::detail::throw_exception(ex);
+      }
+      continue;
+    }
+    else
+    {
+      switch (mask_bytes[i])
+      {
+      case 255:
+        prefix_length_ += 8;
+        break;
+      case 254: // prefix_length_ += 7
+        prefix_length_ += 1;
+      case 252: // prefix_length_ += 6
+        prefix_length_ += 1;
+      case 248: // prefix_length_ += 5
+        prefix_length_ += 1;
+      case 240: // prefix_length_ += 4
+        prefix_length_ += 1;
+      case 224: // prefix_length_ += 3
+        prefix_length_ += 1;
+      case 192: // prefix_length_ += 2
+        prefix_length_ += 1;
+      case 128: // prefix_length_ += 1
+        prefix_length_ += 1;
+      case 0:   // nbits += 0
+        finished = true;
+        break;
+      default:
+        std::out_of_range ex("non-contiguous netmask");
+        asio::detail::throw_exception(ex);
+      }
+    }
+  }
+}
+
+address_v4 network_v4::netmask() const ASIO_NOEXCEPT
+{
+  uint32_t nmbits = 0xffffffff;
+  if (prefix_length_ == 0)
+    nmbits = 0;
+  else
+    nmbits = nmbits << (32 - prefix_length_);
+  return address_v4(nmbits);
+}
+
+address_v4_range network_v4::hosts() const ASIO_NOEXCEPT
+{
+  return is_host()
+    ? address_v4_range(address_, address_v4(address_.to_uint() + 1))
+    : address_v4_range(address_v4(network().to_uint() + 1), broadcast());
+}
+
+bool network_v4::is_subnet_of(const network_v4& other) const
+{
+  if (other.prefix_length_ >= prefix_length_)
+    return false; // Only real subsets are allowed.
+  const network_v4 me(address_, other.prefix_length_);
+  return other.canonical() == me.canonical();
+}
+
+std::string network_v4::to_string() const
+{
+  asio::error_code ec;
+  std::string addr = to_string(ec);
+  asio::detail::throw_error(ec);
+  return addr;
+}
+
+std::string network_v4::to_string(asio::error_code& ec) const
+{
+  using namespace std; // For sprintf.
+  ec = asio::error_code();
+  char prefix_len[16];
+#if defined(ASIO_HAS_SECURE_RTL)
+  sprintf_s(prefix_len, sizeof(prefix_len), "/%u", prefix_length_);
+#else // defined(ASIO_HAS_SECURE_RTL)
+  sprintf(prefix_len, "/%u", prefix_length_);
+#endif // defined(ASIO_HAS_SECURE_RTL)
+  return address_.to_string() + prefix_len;
+}
+
+network_v4 make_network_v4(const char* str)
+{
+  return make_network_v4(std::string(str));
+}
+
+network_v4 make_network_v4(const char* str, asio::error_code& ec)
+{
+  return make_network_v4(std::string(str), ec);
+}
+
+network_v4 make_network_v4(const std::string& str)
+{
+  asio::error_code ec;
+  network_v4 net = make_network_v4(str, ec);
+  asio::detail::throw_error(ec);
+  return net;
+}
+
+network_v4 make_network_v4(const std::string& str,
+    asio::error_code& ec)
+{
+  std::string::size_type pos = str.find_first_of("/");
+
+  if (pos == std::string::npos)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v4();
+  }
+
+  if (pos == str.size() - 1)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v4();
+  }
+
+  std::string::size_type end = str.find_first_not_of("0123456789", pos + 1);
+  if (end != std::string::npos)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v4();
+  }
+
+  const address_v4 addr = make_address_v4(str.substr(0, pos), ec);
+  if (ec)
+    return network_v4();
+
+  const int prefix_len = std::atoi(str.substr(pos + 1).c_str());
+  if (prefix_len < 0 || prefix_len > 32)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v4();
+  }
+
+  return network_v4(addr, static_cast<unsigned short>(prefix_len));
+}
+
+#if defined(ASIO_HAS_STRING_VIEW)
+
+network_v4 make_network_v4(string_view str)
+{
+  return make_network_v4(static_cast<std::string>(str));
+}
+
+network_v4 make_network_v4(string_view str,
+    asio::error_code& ec)
+{
+  return make_network_v4(static_cast<std::string>(str), ec);
+}
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_IMPL_NETWORK_V4_IPP
diff --git a/subprojects/asio/include/asio/ip/impl/network_v6.hpp b/subprojects/asio/include/asio/ip/impl/network_v6.hpp
new file mode 100644
index 000000000..b0eedaded
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/network_v6.hpp
@@ -0,0 +1,53 @@
+//
+// ip/impl/network_v6.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_NETWORK_V6_HPP
+#define ASIO_IP_IMPL_NETWORK_V6_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const network_v6& addr)
+{
+  asio::error_code ec;
+  std::string s = addr.to_string(ec);
+  if (ec)
+  {
+    if (os.exceptions() & std::basic_ostream<Elem, Traits>::failbit)
+      asio::detail::throw_error(ec);
+    else
+      os.setstate(std::basic_ostream<Elem, Traits>::failbit);
+  }
+  else
+    for (std::string::iterator i = s.begin(); i != s.end(); ++i)
+      os << os.widen(*i);
+  return os;
+}
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_IP_IMPL_NETWORK_V6_HPP
diff --git a/subprojects/asio/include/asio/ip/impl/network_v6.ipp b/subprojects/asio/include/asio/ip/impl/network_v6.ipp
new file mode 100644
index 000000000..2e37a99ad
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/impl/network_v6.ipp
@@ -0,0 +1,185 @@
+//
+// ip/impl/network_v6.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2014 Oliver Kowalke (oliver dot kowalke at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_IMPL_NETWORK_V6_IPP
+#define ASIO_IP_IMPL_NETWORK_V6_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <climits>
+#include <cstdio>
+#include <cstdlib>
+#include <stdexcept>
+#include "asio/error.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/throw_exception.hpp"
+#include "asio/ip/network_v6.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+network_v6::network_v6(const address_v6& addr, unsigned short prefix_len)
+  : address_(addr),
+    prefix_length_(prefix_len)
+{
+  if (prefix_len > 128)
+  {
+    std::out_of_range ex("prefix length too large");
+    asio::detail::throw_exception(ex);
+  }
+}
+
+ASIO_DECL address_v6 network_v6::network() const ASIO_NOEXCEPT
+{
+  address_v6::bytes_type bytes(address_.to_bytes());
+  for (std::size_t i = 0; i < 16; ++i)
+  {
+    if (prefix_length_ <= i * 8)
+      bytes[i] = 0;
+    else if (prefix_length_ < (i + 1) * 8)
+      bytes[i] &= 0xFF00 >> (prefix_length_ % 8);
+  }
+  return address_v6(bytes, address_.scope_id());
+}
+
+address_v6_range network_v6::hosts() const ASIO_NOEXCEPT
+{
+  address_v6::bytes_type begin_bytes(address_.to_bytes());
+  address_v6::bytes_type end_bytes(address_.to_bytes());
+  for (std::size_t i = 0; i < 16; ++i)
+  {
+    if (prefix_length_ <= i * 8)
+    {
+      begin_bytes[i] = 0;
+      end_bytes[i] = 0xFF;
+    }
+    else if (prefix_length_ < (i + 1) * 8)
+    {
+      begin_bytes[i] &= 0xFF00 >> (prefix_length_ % 8);
+      end_bytes[i] |= 0xFF >> (prefix_length_ % 8);
+    }
+  }
+  return address_v6_range(
+      address_v6_iterator(address_v6(begin_bytes, address_.scope_id())),
+      ++address_v6_iterator(address_v6(end_bytes, address_.scope_id())));
+}
+
+bool network_v6::is_subnet_of(const network_v6& other) const
+{
+  if (other.prefix_length_ >= prefix_length_)
+    return false; // Only real subsets are allowed.
+  const network_v6 me(address_, other.prefix_length_);
+  return other.canonical() == me.canonical();
+}
+
+std::string network_v6::to_string() const
+{
+  asio::error_code ec;
+  std::string addr = to_string(ec);
+  asio::detail::throw_error(ec);
+  return addr;
+}
+
+std::string network_v6::to_string(asio::error_code& ec) const
+{
+  using namespace std; // For sprintf.
+  ec = asio::error_code();
+  char prefix_len[16];
+#if defined(ASIO_HAS_SECURE_RTL)
+  sprintf_s(prefix_len, sizeof(prefix_len), "/%u", prefix_length_);
+#else // defined(ASIO_HAS_SECURE_RTL)
+  sprintf(prefix_len, "/%u", prefix_length_);
+#endif // defined(ASIO_HAS_SECURE_RTL)
+  return address_.to_string() + prefix_len;
+}
+
+network_v6 make_network_v6(const char* str)
+{
+  return make_network_v6(std::string(str));
+}
+
+network_v6 make_network_v6(const char* str, asio::error_code& ec)
+{
+  return make_network_v6(std::string(str), ec);
+}
+
+network_v6 make_network_v6(const std::string& str)
+{
+  asio::error_code ec;
+  network_v6 net = make_network_v6(str, ec);
+  asio::detail::throw_error(ec);
+  return net;
+}
+
+network_v6 make_network_v6(const std::string& str,
+    asio::error_code& ec)
+{
+  std::string::size_type pos = str.find_first_of("/");
+
+  if (pos == std::string::npos)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v6();
+  }
+
+  if (pos == str.size() - 1)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v6();
+  }
+
+  std::string::size_type end = str.find_first_not_of("0123456789", pos + 1);
+  if (end != std::string::npos)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v6();
+  }
+
+  const address_v6 addr = make_address_v6(str.substr(0, pos), ec);
+  if (ec)
+    return network_v6();
+
+  const int prefix_len = std::atoi(str.substr(pos + 1).c_str());
+  if (prefix_len < 0 || prefix_len > 128)
+  {
+    ec = asio::error::invalid_argument;
+    return network_v6();
+  }
+
+  return network_v6(addr, static_cast<unsigned short>(prefix_len));
+}
+
+#if defined(ASIO_HAS_STRING_VIEW)
+
+network_v6 make_network_v6(string_view str)
+{
+  return make_network_v6(static_cast<std::string>(str));
+}
+
+network_v6 make_network_v6(string_view str,
+    asio::error_code& ec)
+{
+  return make_network_v6(static_cast<std::string>(str), ec);
+}
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_IMPL_NETWORK_V6_IPP
diff --git a/subprojects/asio/include/asio/ip/multicast.hpp b/subprojects/asio/include/asio/ip/multicast.hpp
new file mode 100644
index 000000000..ea624e147
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/multicast.hpp
@@ -0,0 +1,191 @@
+//
+// ip/multicast.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_MULTICAST_HPP
+#define ASIO_IP_MULTICAST_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/ip/detail/socket_option.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+namespace multicast {
+
+/// Socket option to join a multicast group on a specified interface.
+/**
+ * Implements the IPPROTO_IP/IP_ADD_MEMBERSHIP socket option.
+ *
+ * @par Examples
+ * Setting the option to join a multicast group:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::address multicast_address =
+ *   asio::ip::address::from_string("225.0.0.1");
+ * asio::ip::multicast::join_group option(multicast_address);
+ * socket.set_option(option);
+ * @endcode
+ *
+ * @par Concepts:
+ * SettableSocketOption.
+ */
+#if defined(GENERATING_DOCUMENTATION)
+typedef implementation_defined join_group;
+#else
+typedef asio::ip::detail::socket_option::multicast_request<
+  ASIO_OS_DEF(IPPROTO_IP),
+  ASIO_OS_DEF(IP_ADD_MEMBERSHIP),
+  ASIO_OS_DEF(IPPROTO_IPV6),
+  ASIO_OS_DEF(IPV6_JOIN_GROUP)> join_group;
+#endif
+
+/// Socket option to leave a multicast group on a specified interface.
+/**
+ * Implements the IPPROTO_IP/IP_DROP_MEMBERSHIP socket option.
+ *
+ * @par Examples
+ * Setting the option to leave a multicast group:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::address multicast_address =
+ *   asio::ip::address::from_string("225.0.0.1");
+ * asio::ip::multicast::leave_group option(multicast_address);
+ * socket.set_option(option);
+ * @endcode
+ *
+ * @par Concepts:
+ * SettableSocketOption.
+ */
+#if defined(GENERATING_DOCUMENTATION)
+typedef implementation_defined leave_group;
+#else
+typedef asio::ip::detail::socket_option::multicast_request<
+  ASIO_OS_DEF(IPPROTO_IP),
+  ASIO_OS_DEF(IP_DROP_MEMBERSHIP),
+  ASIO_OS_DEF(IPPROTO_IPV6),
+  ASIO_OS_DEF(IPV6_LEAVE_GROUP)> leave_group;
+#endif
+
+/// Socket option for local interface to use for outgoing multicast packets.
+/**
+ * Implements the IPPROTO_IP/IP_MULTICAST_IF socket option.
+ *
+ * @par Examples
+ * Setting the option:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::address_v4 local_interface =
+ *   asio::ip::address_v4::from_string("1.2.3.4");
+ * asio::ip::multicast::outbound_interface option(local_interface);
+ * socket.set_option(option);
+ * @endcode
+ *
+ * @par Concepts:
+ * SettableSocketOption.
+ */
+#if defined(GENERATING_DOCUMENTATION)
+typedef implementation_defined outbound_interface;
+#else
+typedef asio::ip::detail::socket_option::network_interface<
+  ASIO_OS_DEF(IPPROTO_IP),
+  ASIO_OS_DEF(IP_MULTICAST_IF),
+  ASIO_OS_DEF(IPPROTO_IPV6),
+  ASIO_OS_DEF(IPV6_MULTICAST_IF)> outbound_interface;
+#endif
+
+/// Socket option for time-to-live associated with outgoing multicast packets.
+/**
+ * Implements the IPPROTO_IP/IP_MULTICAST_TTL socket option.
+ *
+ * @par Examples
+ * Setting the option:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::multicast::hops option(4);
+ * socket.set_option(option);
+ * @endcode
+ *
+ * @par
+ * Getting the current option value:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::multicast::hops option;
+ * socket.get_option(option);
+ * int ttl = option.value();
+ * @endcode
+ *
+ * @par Concepts:
+ * GettableSocketOption, SettableSocketOption.
+ */
+#if defined(GENERATING_DOCUMENTATION)
+typedef implementation_defined hops;
+#else
+typedef asio::ip::detail::socket_option::multicast_hops<
+  ASIO_OS_DEF(IPPROTO_IP),
+  ASIO_OS_DEF(IP_MULTICAST_TTL),
+  ASIO_OS_DEF(IPPROTO_IPV6),
+  ASIO_OS_DEF(IPV6_MULTICAST_HOPS)> hops;
+#endif
+
+/// Socket option determining whether outgoing multicast packets will be
+/// received on the same socket if it is a member of the multicast group.
+/**
+ * Implements the IPPROTO_IP/IP_MULTICAST_LOOP socket option.
+ *
+ * @par Examples
+ * Setting the option:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::multicast::enable_loopback option(true);
+ * socket.set_option(option);
+ * @endcode
+ *
+ * @par
+ * Getting the current option value:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::multicast::enable_loopback option;
+ * socket.get_option(option);
+ * bool is_set = option.value();
+ * @endcode
+ *
+ * @par Concepts:
+ * GettableSocketOption, SettableSocketOption.
+ */
+#if defined(GENERATING_DOCUMENTATION)
+typedef implementation_defined enable_loopback;
+#else
+typedef asio::ip::detail::socket_option::multicast_enable_loopback<
+  ASIO_OS_DEF(IPPROTO_IP),
+  ASIO_OS_DEF(IP_MULTICAST_LOOP),
+  ASIO_OS_DEF(IPPROTO_IPV6),
+  ASIO_OS_DEF(IPV6_MULTICAST_LOOP)> enable_loopback;
+#endif
+
+} // namespace multicast
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_MULTICAST_HPP
diff --git a/subprojects/asio/include/asio/ip/network_v4.hpp b/subprojects/asio/include/asio/ip/network_v4.hpp
new file mode 100644
index 000000000..e38f60fe9
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/network_v4.hpp
@@ -0,0 +1,261 @@
+//
+// ip/network_v4.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2014 Oliver Kowalke (oliver dot kowalke at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_NETWORK_V4_HPP
+#define ASIO_IP_NETWORK_V4_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/string_view.hpp"
+#include "asio/error_code.hpp"
+#include "asio/ip/address_v4_range.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Represents an IPv4 network.
+/**
+ * The asio::ip::network_v4 class provides the ability to use and
+ * manipulate IP version 4 networks.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class network_v4
+{
+public:
+  /// Default constructor.
+  network_v4() ASIO_NOEXCEPT
+    : address_(),
+      prefix_length_(0)
+  {
+  }
+
+  /// Construct a network based on the specified address and prefix length.
+  ASIO_DECL network_v4(const address_v4& addr,
+      unsigned short prefix_len);
+
+  /// Construct network based on the specified address and netmask.
+  ASIO_DECL network_v4(const address_v4& addr,
+      const address_v4& mask);
+
+  /// Copy constructor.
+  network_v4(const network_v4& other) ASIO_NOEXCEPT
+    : address_(other.address_),
+      prefix_length_(other.prefix_length_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  network_v4(network_v4&& other) ASIO_NOEXCEPT
+    : address_(ASIO_MOVE_CAST(address_v4)(other.address_)),
+      prefix_length_(other.prefix_length_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from another network.
+  network_v4& operator=(const network_v4& other) ASIO_NOEXCEPT
+  {
+    address_ = other.address_;
+    prefix_length_ = other.prefix_length_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move-assign from another network.
+  network_v4& operator=(network_v4&& other) ASIO_NOEXCEPT
+  {
+    address_ = ASIO_MOVE_CAST(address_v4)(other.address_);
+    prefix_length_ = other.prefix_length_;
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Obtain the address object specified when the network object was created.
+  address_v4 address() const ASIO_NOEXCEPT
+  {
+    return address_;
+  }
+
+  /// Obtain the prefix length that was specified when the network object was
+  /// created.
+  unsigned short prefix_length() const ASIO_NOEXCEPT
+  {
+    return prefix_length_;
+  }
+
+  /// Obtain the netmask that was specified when the network object was created.
+  ASIO_DECL address_v4 netmask() const ASIO_NOEXCEPT;
+
+  /// Obtain an address object that represents the network address.
+  address_v4 network() const ASIO_NOEXCEPT
+  {
+    return address_v4(address_.to_uint() & netmask().to_uint());
+  }
+
+  /// Obtain an address object that represents the network's broadcast address.
+  address_v4 broadcast() const ASIO_NOEXCEPT
+  {
+    return address_v4(network().to_uint() | (netmask().to_uint() ^ 0xFFFFFFFF));
+  }
+
+  /// Obtain an address range corresponding to the hosts in the network.
+  ASIO_DECL address_v4_range hosts() const ASIO_NOEXCEPT;
+
+  /// Obtain the true network address, omitting any host bits.
+  network_v4 canonical() const ASIO_NOEXCEPT
+  {
+    return network_v4(network(), netmask());
+  }
+
+  /// Test if network is a valid host address.
+  bool is_host() const ASIO_NOEXCEPT
+  {
+    return prefix_length_ == 32;
+  }
+
+  /// Test if a network is a real subnet of another network.
+  ASIO_DECL bool is_subnet_of(const network_v4& other) const;
+
+  /// Get the network as an address in dotted decimal format.
+  ASIO_DECL std::string to_string() const;
+
+  /// Get the network as an address in dotted decimal format.
+  ASIO_DECL std::string to_string(asio::error_code& ec) const;
+
+  /// Compare two networks for equality.
+  friend bool operator==(const network_v4& a, const network_v4& b)
+  {
+    return a.address_ == b.address_ && a.prefix_length_ == b.prefix_length_;
+  }
+
+  /// Compare two networks for inequality.
+  friend bool operator!=(const network_v4& a, const network_v4& b)
+  {
+    return !(a == b);
+  }
+
+private:
+  address_v4 address_;
+  unsigned short prefix_length_;
+};
+
+/// Create an IPv4 network from an address and prefix length.
+/**
+ * @relates address_v4
+ */
+inline network_v4 make_network_v4(
+    const address_v4& addr, unsigned short prefix_len)
+{
+  return network_v4(addr, prefix_len);
+}
+
+/// Create an IPv4 network from an address and netmask.
+/**
+ * @relates address_v4
+ */
+inline network_v4 make_network_v4(
+    const address_v4& addr, const address_v4& mask)
+{
+  return network_v4(addr, mask);
+}
+
+/// Create an IPv4 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v4
+ */
+ASIO_DECL network_v4 make_network_v4(const char* str);
+
+/// Create an IPv4 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v4
+ */
+ASIO_DECL network_v4 make_network_v4(
+    const char* str, asio::error_code& ec);
+
+/// Create an IPv4 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v4
+ */
+ASIO_DECL network_v4 make_network_v4(const std::string& str);
+
+/// Create an IPv4 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v4
+ */
+ASIO_DECL network_v4 make_network_v4(
+    const std::string& str, asio::error_code& ec);
+
+#if defined(ASIO_HAS_STRING_VIEW) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Create an IPv4 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v4
+ */
+ASIO_DECL network_v4 make_network_v4(string_view str);
+
+/// Create an IPv4 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v4
+ */
+ASIO_DECL network_v4 make_network_v4(
+    string_view str, asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Output a network as a string.
+/**
+ * Used to output a human-readable string for a specified network.
+ *
+ * @param os The output stream to which the string will be written.
+ *
+ * @param net The network to be written.
+ *
+ * @return The output stream.
+ *
+ * @relates asio::ip::address_v4
+ */
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const network_v4& net);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/ip/impl/network_v4.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ip/impl/network_v4.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_IP_NETWORK_V4_HPP
diff --git a/subprojects/asio/include/asio/ip/network_v6.hpp b/subprojects/asio/include/asio/ip/network_v6.hpp
new file mode 100644
index 000000000..7b6b7e613
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/network_v6.hpp
@@ -0,0 +1,235 @@
+//
+// ip/network_v6.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2014 Oliver Kowalke (oliver dot kowalke at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_NETWORK_V6_HPP
+#define ASIO_IP_NETWORK_V6_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <string>
+#include "asio/detail/string_view.hpp"
+#include "asio/error_code.hpp"
+#include "asio/ip/address_v6_range.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Represents an IPv6 network.
+/**
+ * The asio::ip::network_v6 class provides the ability to use and
+ * manipulate IP version 6 networks.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class network_v6
+{
+public:
+  /// Default constructor.
+  network_v6() ASIO_NOEXCEPT
+    : address_(),
+      prefix_length_(0)
+  {
+  }
+
+  /// Construct a network based on the specified address and prefix length.
+  ASIO_DECL network_v6(const address_v6& addr,
+      unsigned short prefix_len);
+
+  /// Copy constructor.
+  network_v6(const network_v6& other) ASIO_NOEXCEPT
+    : address_(other.address_),
+      prefix_length_(other.prefix_length_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  network_v6(network_v6&& other) ASIO_NOEXCEPT
+    : address_(ASIO_MOVE_CAST(address_v6)(other.address_)),
+      prefix_length_(other.prefix_length_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from another network.
+  network_v6& operator=(const network_v6& other) ASIO_NOEXCEPT
+  {
+    address_ = other.address_;
+    prefix_length_ = other.prefix_length_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move-assign from another network.
+  network_v6& operator=(network_v6&& other) ASIO_NOEXCEPT
+  {
+    address_ = ASIO_MOVE_CAST(address_v6)(other.address_);
+    prefix_length_ = other.prefix_length_;
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Obtain the address object specified when the network object was created.
+  address_v6 address() const ASIO_NOEXCEPT
+  {
+    return address_;
+  }
+
+  /// Obtain the prefix length that was specified when the network object was
+  /// created.
+  unsigned short prefix_length() const ASIO_NOEXCEPT
+  {
+    return prefix_length_;
+  }
+
+  /// Obtain an address object that represents the network address.
+  ASIO_DECL address_v6 network() const ASIO_NOEXCEPT;
+
+  /// Obtain an address range corresponding to the hosts in the network.
+  ASIO_DECL address_v6_range hosts() const ASIO_NOEXCEPT;
+
+  /// Obtain the true network address, omitting any host bits.
+  network_v6 canonical() const ASIO_NOEXCEPT
+  {
+    return network_v6(network(), prefix_length());
+  }
+
+  /// Test if network is a valid host address.
+  bool is_host() const ASIO_NOEXCEPT
+  {
+    return prefix_length_ == 128;
+  }
+
+  /// Test if a network is a real subnet of another network.
+  ASIO_DECL bool is_subnet_of(const network_v6& other) const;
+
+  /// Get the network as an address in dotted decimal format.
+  ASIO_DECL std::string to_string() const;
+
+  /// Get the network as an address in dotted decimal format.
+  ASIO_DECL std::string to_string(asio::error_code& ec) const;
+
+  /// Compare two networks for equality.
+  friend bool operator==(const network_v6& a, const network_v6& b)
+  {
+    return a.address_ == b.address_ && a.prefix_length_ == b.prefix_length_;
+  }
+
+  /// Compare two networks for inequality.
+  friend bool operator!=(const network_v6& a, const network_v6& b)
+  {
+    return !(a == b);
+  }
+
+private:
+  address_v6 address_;
+  unsigned short prefix_length_;
+};
+
+/// Create an IPv6 network from an address and prefix length.
+/**
+ * @relates address_v6
+ */
+inline network_v6 make_network_v6(
+    const address_v6& addr, unsigned short prefix_len)
+{
+  return network_v6(addr, prefix_len);
+}
+
+/// Create an IPv6 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v6
+ */
+ASIO_DECL network_v6 make_network_v6(const char* str);
+
+/// Create an IPv6 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v6
+ */
+ASIO_DECL network_v6 make_network_v6(
+    const char* str, asio::error_code& ec);
+
+/// Create an IPv6 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v6
+ */
+ASIO_DECL network_v6 make_network_v6(const std::string& str);
+
+/// Create an IPv6 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v6
+ */
+ASIO_DECL network_v6 make_network_v6(
+    const std::string& str, asio::error_code& ec);
+
+#if defined(ASIO_HAS_STRING_VIEW) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Create an IPv6 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v6
+ */
+ASIO_DECL network_v6 make_network_v6(string_view str);
+
+/// Create an IPv6 network from a string containing IP address and prefix
+/// length.
+/**
+ * @relates network_v6
+ */
+ASIO_DECL network_v6 make_network_v6(
+    string_view str, asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_STRING_VIEW)
+       //  || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Output a network as a string.
+/**
+ * Used to output a human-readable string for a specified network.
+ *
+ * @param os The output stream to which the string will be written.
+ *
+ * @param net The network to be written.
+ *
+ * @return The output stream.
+ *
+ * @relates asio::ip::address_v6
+ */
+template <typename Elem, typename Traits>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os, const network_v6& net);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/ip/impl/network_v6.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ip/impl/network_v6.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_IP_NETWORK_V6_HPP
diff --git a/subprojects/asio/include/asio/ip/resolver_base.hpp b/subprojects/asio/include/asio/ip/resolver_base.hpp
new file mode 100644
index 000000000..d32c9110d
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/resolver_base.hpp
@@ -0,0 +1,129 @@
+//
+// ip/resolver_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_RESOLVER_BASE_HPP
+#define ASIO_IP_RESOLVER_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// The resolver_base class is used as a base for the basic_resolver class
+/// templates to provide a common place to define the flag constants.
+class resolver_base
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// A bitmask type (C++ Std [lib.bitmask.types]).
+  typedef unspecified flags;
+
+  /// Determine the canonical name of the host specified in the query.
+  static const flags canonical_name = implementation_defined;
+
+  /// Indicate that returned endpoint is intended for use as a locally bound
+  /// socket endpoint.
+  static const flags passive = implementation_defined;
+
+  /// Host name should be treated as a numeric string defining an IPv4 or IPv6
+  /// address and no name resolution should be attempted.
+  static const flags numeric_host = implementation_defined;
+
+  /// Service name should be treated as a numeric string defining a port number
+  /// and no name resolution should be attempted.
+  static const flags numeric_service = implementation_defined;
+
+  /// If the query protocol family is specified as IPv6, return IPv4-mapped
+  /// IPv6 addresses on finding no IPv6 addresses.
+  static const flags v4_mapped = implementation_defined;
+
+  /// If used with v4_mapped, return all matching IPv6 and IPv4 addresses.
+  static const flags all_matching = implementation_defined;
+
+  /// Only return IPv4 addresses if a non-loopback IPv4 address is configured
+  /// for the system. Only return IPv6 addresses if a non-loopback IPv6 address
+  /// is configured for the system.
+  static const flags address_configured = implementation_defined;
+#else
+  enum flags
+  {
+    canonical_name = ASIO_OS_DEF(AI_CANONNAME),
+    passive = ASIO_OS_DEF(AI_PASSIVE),
+    numeric_host = ASIO_OS_DEF(AI_NUMERICHOST),
+    numeric_service = ASIO_OS_DEF(AI_NUMERICSERV),
+    v4_mapped = ASIO_OS_DEF(AI_V4MAPPED),
+    all_matching = ASIO_OS_DEF(AI_ALL),
+    address_configured = ASIO_OS_DEF(AI_ADDRCONFIG)
+  };
+
+  // Implement bitmask operations as shown in C++ Std [lib.bitmask.types].
+
+  friend flags operator&(flags x, flags y)
+  {
+    return static_cast<flags>(
+        static_cast<unsigned int>(x) & static_cast<unsigned int>(y));
+  }
+
+  friend flags operator|(flags x, flags y)
+  {
+    return static_cast<flags>(
+        static_cast<unsigned int>(x) | static_cast<unsigned int>(y));
+  }
+
+  friend flags operator^(flags x, flags y)
+  {
+    return static_cast<flags>(
+        static_cast<unsigned int>(x) ^ static_cast<unsigned int>(y));
+  }
+
+  friend flags operator~(flags x)
+  {
+    return static_cast<flags>(~static_cast<unsigned int>(x));
+  }
+
+  friend flags& operator&=(flags& x, flags y)
+  {
+    x = x & y;
+    return x;
+  }
+
+  friend flags& operator|=(flags& x, flags y)
+  {
+    x = x | y;
+    return x;
+  }
+
+  friend flags& operator^=(flags& x, flags y)
+  {
+    x = x ^ y;
+    return x;
+  }
+#endif
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~resolver_base()
+  {
+  }
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_RESOLVER_BASE_HPP
diff --git a/subprojects/asio/include/asio/ip/resolver_query_base.hpp b/subprojects/asio/include/asio/ip/resolver_query_base.hpp
new file mode 100644
index 000000000..be368589e
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/resolver_query_base.hpp
@@ -0,0 +1,43 @@
+//
+// ip/resolver_query_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_RESOLVER_QUERY_BASE_HPP
+#define ASIO_IP_RESOLVER_QUERY_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ip/resolver_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// The resolver_query_base class is used as a base for the
+/// basic_resolver_query class templates to provide a common place to define
+/// the flag constants.
+class resolver_query_base : public resolver_base
+{
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~resolver_query_base()
+  {
+  }
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_RESOLVER_QUERY_BASE_HPP
diff --git a/subprojects/asio/include/asio/ip/resolver_service.hpp b/subprojects/asio/include/asio/ip/resolver_service.hpp
new file mode 100644
index 000000000..519d72dbb
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/resolver_service.hpp
@@ -0,0 +1,200 @@
+//
+// ip/resolver_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_RESOLVER_SERVICE_HPP
+#define ASIO_IP_RESOLVER_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/async_result.hpp"
+#include "asio/error_code.hpp"
+#include "asio/io_context.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+#include "asio/ip/basic_resolver_results.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/winrt_resolver_service.hpp"
+#else
+# include "asio/detail/resolver_service.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Default service implementation for a resolver.
+template <typename InternetProtocol>
+class resolver_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<
+      resolver_service<InternetProtocol> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The protocol type.
+  typedef InternetProtocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename InternetProtocol::endpoint endpoint_type;
+
+  /// The query type.
+  typedef basic_resolver_query<InternetProtocol> query_type;
+
+  /// The iterator type.
+  typedef basic_resolver_iterator<InternetProtocol> iterator_type;
+
+  /// The results type.
+  typedef basic_resolver_results<InternetProtocol> results_type;
+
+private:
+  // The type of the platform-specific implementation.
+#if defined(ASIO_WINDOWS_RUNTIME)
+  typedef asio::detail::winrt_resolver_service<InternetProtocol>
+    service_impl_type;
+#else
+  typedef asio::detail::resolver_service<InternetProtocol>
+    service_impl_type;
+#endif
+
+public:
+  /// The type of a resolver implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// Construct a new resolver service for the specified io_context.
+  explicit resolver_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        resolver_service<InternetProtocol> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new resolver implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new resolver implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another resolver implementation.
+  void move_assign(implementation_type& impl,
+      resolver_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a resolver implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Cancel pending asynchronous operations.
+  void cancel(implementation_type& impl)
+  {
+    service_impl_.cancel(impl);
+  }
+
+  /// Resolve a query to a list of entries.
+  results_type resolve(implementation_type& impl, const query_type& query,
+      asio::error_code& ec)
+  {
+    return service_impl_.resolve(impl, query, ec);
+  }
+
+  /// Asynchronously resolve a query to a list of entries.
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(implementation_type& impl, const query_type& query,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    asio::async_completion<ResolveHandler,
+      void (asio::error_code, results_type)> init(handler);
+
+    service_impl_.async_resolve(impl, query, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Resolve an endpoint to a list of entries.
+  results_type resolve(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    return service_impl_.resolve(impl, endpoint, ec);
+  }
+
+  /// Asynchronously resolve an endpoint to a list of entries.
+  template <typename ResolveHandler>
+  ASIO_INITFN_RESULT_TYPE(ResolveHandler,
+      void (asio::error_code, results_type))
+  async_resolve(implementation_type& impl, const endpoint_type& endpoint,
+      ASIO_MOVE_ARG(ResolveHandler) handler)
+  {
+    asio::async_completion<ResolveHandler,
+      void (asio::error_code, results_type)> init(handler);
+
+    service_impl_.async_resolve(impl, endpoint, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // Perform any fork-related housekeeping.
+  void notify_fork(asio::io_context::fork_event event)
+  {
+    service_impl_.notify_fork(event);
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_IP_RESOLVER_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/ip/tcp.hpp b/subprojects/asio/include/asio/ip/tcp.hpp
new file mode 100644
index 000000000..f1adeb02c
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/tcp.hpp
@@ -0,0 +1,155 @@
+//
+// ip/tcp.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_TCP_HPP
+#define ASIO_IP_TCP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/basic_socket_acceptor.hpp"
+#include "asio/basic_socket_iostream.hpp"
+#include "asio/basic_stream_socket.hpp"
+#include "asio/detail/socket_option.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/ip/basic_endpoint.hpp"
+#include "asio/ip/basic_resolver.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Encapsulates the flags needed for TCP.
+/**
+ * The asio::ip::tcp class contains flags necessary for TCP sockets.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol, InternetProtocol.
+ */
+class tcp
+{
+public:
+  /// The type of a TCP endpoint.
+  typedef basic_endpoint<tcp> endpoint;
+
+  /// Construct to represent the IPv4 TCP protocol.
+  static tcp v4()
+  {
+    return tcp(ASIO_OS_DEF(AF_INET));
+  }
+
+  /// Construct to represent the IPv6 TCP protocol.
+  static tcp v6()
+  {
+    return tcp(ASIO_OS_DEF(AF_INET6));
+  }
+
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return ASIO_OS_DEF(SOCK_STREAM);
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return ASIO_OS_DEF(IPPROTO_TCP);
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return family_;
+  }
+
+  /// The TCP socket type.
+  typedef basic_stream_socket<tcp> socket;
+
+  /// The TCP acceptor type.
+  typedef basic_socket_acceptor<tcp> acceptor;
+
+  /// The TCP resolver type.
+  typedef basic_resolver<tcp> resolver;
+
+#if !defined(ASIO_NO_IOSTREAM)
+  /// The TCP iostream type.
+  typedef basic_socket_iostream<tcp> iostream;
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+  /// Socket option for disabling the Nagle algorithm.
+  /**
+   * Implements the IPPROTO_TCP/TCP_NODELAY socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::ip::tcp::no_delay option(true);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::ip::tcp::no_delay option;
+   * socket.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined no_delay;
+#else
+  typedef asio::detail::socket_option::boolean<
+    ASIO_OS_DEF(IPPROTO_TCP), ASIO_OS_DEF(TCP_NODELAY)> no_delay;
+#endif
+
+  /// Compare two protocols for equality.
+  friend bool operator==(const tcp& p1, const tcp& p2)
+  {
+    return p1.family_ == p2.family_;
+  }
+
+  /// Compare two protocols for inequality.
+  friend bool operator!=(const tcp& p1, const tcp& p2)
+  {
+    return p1.family_ != p2.family_;
+  }
+
+private:
+  // Construct with a specific family.
+  explicit tcp(int protocol_family)
+    : family_(protocol_family)
+  {
+  }
+
+  int family_;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_TCP_HPP
diff --git a/subprojects/asio/include/asio/ip/udp.hpp b/subprojects/asio/include/asio/ip/udp.hpp
new file mode 100644
index 000000000..1c93f9b0a
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/udp.hpp
@@ -0,0 +1,111 @@
+//
+// ip/udp.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_UDP_HPP
+#define ASIO_IP_UDP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/basic_datagram_socket.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/ip/basic_endpoint.hpp"
+#include "asio/ip/basic_resolver.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Encapsulates the flags needed for UDP.
+/**
+ * The asio::ip::udp class contains flags necessary for UDP sockets.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol, InternetProtocol.
+ */
+class udp
+{
+public:
+  /// The type of a UDP endpoint.
+  typedef basic_endpoint<udp> endpoint;
+
+  /// Construct to represent the IPv4 UDP protocol.
+  static udp v4()
+  {
+    return udp(ASIO_OS_DEF(AF_INET));
+  }
+
+  /// Construct to represent the IPv6 UDP protocol.
+  static udp v6()
+  {
+    return udp(ASIO_OS_DEF(AF_INET6));
+  }
+
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return ASIO_OS_DEF(SOCK_DGRAM);
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return ASIO_OS_DEF(IPPROTO_UDP);
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return family_;
+  }
+
+  /// The UDP socket type.
+  typedef basic_datagram_socket<udp> socket;
+
+  /// The UDP resolver type.
+  typedef basic_resolver<udp> resolver;
+
+  /// Compare two protocols for equality.
+  friend bool operator==(const udp& p1, const udp& p2)
+  {
+    return p1.family_ == p2.family_;
+  }
+
+  /// Compare two protocols for inequality.
+  friend bool operator!=(const udp& p1, const udp& p2)
+  {
+    return p1.family_ != p2.family_;
+  }
+
+private:
+  // Construct with a specific family.
+  explicit udp(int protocol_family)
+    : family_(protocol_family)
+  {
+  }
+
+  int family_;
+};
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_UDP_HPP
diff --git a/subprojects/asio/include/asio/ip/unicast.hpp b/subprojects/asio/include/asio/ip/unicast.hpp
new file mode 100644
index 000000000..14e3e489f
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/unicast.hpp
@@ -0,0 +1,70 @@
+//
+// ip/unicast.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_UNICAST_HPP
+#define ASIO_IP_UNICAST_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/ip/detail/socket_option.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+namespace unicast {
+
+/// Socket option for time-to-live associated with outgoing unicast packets.
+/**
+ * Implements the IPPROTO_IP/IP_UNICAST_TTL socket option.
+ *
+ * @par Examples
+ * Setting the option:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::unicast::hops option(4);
+ * socket.set_option(option);
+ * @endcode
+ *
+ * @par
+ * Getting the current option value:
+ * @code
+ * asio::ip::udp::socket socket(io_context); 
+ * ...
+ * asio::ip::unicast::hops option;
+ * socket.get_option(option);
+ * int ttl = option.value();
+ * @endcode
+ *
+ * @par Concepts:
+ * GettableSocketOption, SettableSocketOption.
+ */
+#if defined(GENERATING_DOCUMENTATION)
+typedef implementation_defined hops;
+#else
+typedef asio::ip::detail::socket_option::unicast_hops<
+  ASIO_OS_DEF(IPPROTO_IP),
+  ASIO_OS_DEF(IP_TTL),
+  ASIO_OS_DEF(IPPROTO_IPV6),
+  ASIO_OS_DEF(IPV6_UNICAST_HOPS)> hops;
+#endif
+
+} // namespace unicast
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_UNICAST_HPP
diff --git a/subprojects/asio/include/asio/ip/v6_only.hpp b/subprojects/asio/include/asio/ip/v6_only.hpp
new file mode 100644
index 000000000..ac7234edc
--- /dev/null
+++ b/subprojects/asio/include/asio/ip/v6_only.hpp
@@ -0,0 +1,69 @@
+//
+// ip/v6_only.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IP_V6_ONLY_HPP
+#define ASIO_IP_V6_ONLY_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/socket_option.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ip {
+
+/// Socket option for determining whether an IPv6 socket supports IPv6
+/// communication only.
+/**
+ * Implements the IPPROTO_IPV6/IP_V6ONLY socket option.
+ *
+ * @par Examples
+ * Setting the option:
+ * @code
+ * asio::ip::tcp::socket socket(io_context); 
+ * ...
+ * asio::ip::v6_only option(true);
+ * socket.set_option(option);
+ * @endcode
+ *
+ * @par
+ * Getting the current option value:
+ * @code
+ * asio::ip::tcp::socket socket(io_context); 
+ * ...
+ * asio::ip::v6_only option;
+ * socket.get_option(option);
+ * bool v6_only = option.value();
+ * @endcode
+ *
+ * @par Concepts:
+ * GettableSocketOption, SettableSocketOption.
+ */
+#if defined(GENERATING_DOCUMENTATION)
+typedef implementation_defined v6_only;
+#elif defined(IPV6_V6ONLY)
+typedef asio::detail::socket_option::boolean<
+    IPPROTO_IPV6, IPV6_V6ONLY> v6_only;
+#else
+typedef asio::detail::socket_option::boolean<
+    asio::detail::custom_socket_option_level,
+    asio::detail::always_fail_option> v6_only;
+#endif
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IP_V6_ONLY_HPP
diff --git a/subprojects/asio/include/asio/is_executor.hpp b/subprojects/asio/include/asio/is_executor.hpp
new file mode 100644
index 000000000..a1661ec46
--- /dev/null
+++ b/subprojects/asio/include/asio/is_executor.hpp
@@ -0,0 +1,46 @@
+//
+// is_executor.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IS_EXECUTOR_HPP
+#define ASIO_IS_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/is_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// The is_executor trait detects whether a type T meets the Executor type
+/// requirements.
+/**
+ * Class template @c is_executor is a UnaryTypeTrait that is derived from @c
+ * true_type if the type @c T meets the syntactic requirements for Executor,
+ * otherwise @c false_type.
+ */
+template <typename T>
+struct is_executor
+#if defined(GENERATING_DOCUMENTATION)
+  : integral_constant<bool, automatically_determined>
+#else // defined(GENERATING_DOCUMENTATION)
+  : asio::detail::is_executor<T>
+#endif // defined(GENERATING_DOCUMENTATION)
+{
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IS_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/is_read_buffered.hpp b/subprojects/asio/include/asio/is_read_buffered.hpp
new file mode 100644
index 000000000..c5a67b2da
--- /dev/null
+++ b/subprojects/asio/include/asio/is_read_buffered.hpp
@@ -0,0 +1,59 @@
+//
+// is_read_buffered.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IS_READ_BUFFERED_HPP
+#define ASIO_IS_READ_BUFFERED_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/buffered_read_stream_fwd.hpp"
+#include "asio/buffered_stream_fwd.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail {
+
+template <typename Stream>
+char is_read_buffered_helper(buffered_stream<Stream>* s);
+
+template <typename Stream>
+char is_read_buffered_helper(buffered_read_stream<Stream>* s);
+
+struct is_read_buffered_big_type { char data[10]; };
+is_read_buffered_big_type is_read_buffered_helper(...);
+
+} // namespace detail
+
+/// The is_read_buffered class is a traits class that may be used to determine
+/// whether a stream type supports buffering of read data.
+template <typename Stream>
+class is_read_buffered
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The value member is true only if the Stream type supports buffering of
+  /// read data.
+  static const bool value;
+#else
+  ASIO_STATIC_CONSTANT(bool,
+      value = sizeof(detail::is_read_buffered_helper((Stream*)0)) == 1);
+#endif
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IS_READ_BUFFERED_HPP
diff --git a/subprojects/asio/include/asio/is_write_buffered.hpp b/subprojects/asio/include/asio/is_write_buffered.hpp
new file mode 100644
index 000000000..e237dd6f4
--- /dev/null
+++ b/subprojects/asio/include/asio/is_write_buffered.hpp
@@ -0,0 +1,59 @@
+//
+// is_write_buffered.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IS_WRITE_BUFFERED_HPP
+#define ASIO_IS_WRITE_BUFFERED_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/buffered_stream_fwd.hpp"
+#include "asio/buffered_write_stream_fwd.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail {
+
+template <typename Stream>
+char is_write_buffered_helper(buffered_stream<Stream>* s);
+
+template <typename Stream>
+char is_write_buffered_helper(buffered_write_stream<Stream>* s);
+
+struct is_write_buffered_big_type { char data[10]; };
+is_write_buffered_big_type is_write_buffered_helper(...);
+
+} // namespace detail
+
+/// The is_write_buffered class is a traits class that may be used to determine
+/// whether a stream type supports buffering of written data.
+template <typename Stream>
+class is_write_buffered
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The value member is true only if the Stream type supports buffering of
+  /// written data.
+  static const bool value;
+#else
+  ASIO_STATIC_CONSTANT(bool,
+      value = sizeof(detail::is_write_buffered_helper((Stream*)0)) == 1);
+#endif
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IS_WRITE_BUFFERED_HPP
diff --git a/subprojects/asio/include/asio/local/basic_endpoint.hpp b/subprojects/asio/include/asio/local/basic_endpoint.hpp
new file mode 100644
index 000000000..94e470a4b
--- /dev/null
+++ b/subprojects/asio/include/asio/local/basic_endpoint.hpp
@@ -0,0 +1,239 @@
+//
+// local/basic_endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Derived from a public domain implementation written by Daniel Casimiro.
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_LOCAL_BASIC_ENDPOINT_HPP
+#define ASIO_LOCAL_BASIC_ENDPOINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/local/detail/endpoint.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+# include <iosfwd>
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace local {
+
+/// Describes an endpoint for a UNIX socket.
+/**
+ * The asio::local::basic_endpoint class template describes an endpoint
+ * that may be associated with a particular UNIX socket.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * Endpoint.
+ */
+template <typename Protocol>
+class basic_endpoint
+{
+public:
+  /// The protocol type associated with the endpoint.
+  typedef Protocol protocol_type;
+
+  /// The type of the endpoint structure. This type is dependent on the
+  /// underlying implementation of the socket layer.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined data_type;
+#else
+  typedef asio::detail::socket_addr_type data_type;
+#endif
+
+  /// Default constructor.
+  basic_endpoint()
+  {
+  }
+
+  /// Construct an endpoint using the specified path name.
+  basic_endpoint(const char* path_name)
+    : impl_(path_name)
+  {
+  }
+
+  /// Construct an endpoint using the specified path name.
+  basic_endpoint(const std::string& path_name)
+    : impl_(path_name)
+  {
+  }
+
+  /// Copy constructor.
+  basic_endpoint(const basic_endpoint& other)
+    : impl_(other.impl_)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move constructor.
+  basic_endpoint(basic_endpoint&& other)
+    : impl_(other.impl_)
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Assign from another endpoint.
+  basic_endpoint& operator=(const basic_endpoint& other)
+  {
+    impl_ = other.impl_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Move-assign from another endpoint.
+  basic_endpoint& operator=(basic_endpoint&& other)
+  {
+    impl_ = other.impl_;
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// The protocol associated with the endpoint.
+  protocol_type protocol() const
+  {
+    return protocol_type();
+  }
+
+  /// Get the underlying endpoint in the native type.
+  data_type* data()
+  {
+    return impl_.data();
+  }
+
+  /// Get the underlying endpoint in the native type.
+  const data_type* data() const
+  {
+    return impl_.data();
+  }
+
+  /// Get the underlying size of the endpoint in the native type.
+  std::size_t size() const
+  {
+    return impl_.size();
+  }
+
+  /// Set the underlying size of the endpoint in the native type.
+  void resize(std::size_t new_size)
+  {
+    impl_.resize(new_size);
+  }
+
+  /// Get the capacity of the endpoint in the native type.
+  std::size_t capacity() const
+  {
+    return impl_.capacity();
+  }
+
+  /// Get the path associated with the endpoint.
+  std::string path() const
+  {
+    return impl_.path();
+  }
+
+  /// Set the path associated with the endpoint.
+  void path(const char* p)
+  {
+    impl_.path(p);
+  }
+
+  /// Set the path associated with the endpoint.
+  void path(const std::string& p)
+  {
+    impl_.path(p);
+  }
+
+  /// Compare two endpoints for equality.
+  friend bool operator==(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return e1.impl_ == e2.impl_;
+  }
+
+  /// Compare two endpoints for inequality.
+  friend bool operator!=(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return !(e1.impl_ == e2.impl_);
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator<(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return e1.impl_ < e2.impl_;
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator>(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return e2.impl_ < e1.impl_;
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator<=(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return !(e2 < e1);
+  }
+
+  /// Compare endpoints for ordering.
+  friend bool operator>=(const basic_endpoint<Protocol>& e1,
+      const basic_endpoint<Protocol>& e2)
+  {
+    return !(e1 < e2);
+  }
+
+private:
+  // The underlying UNIX domain endpoint.
+  asio::local::detail::endpoint impl_;
+};
+
+/// Output an endpoint as a string.
+/**
+ * Used to output a human-readable string for a specified endpoint.
+ *
+ * @param os The output stream to which the string will be written.
+ *
+ * @param endpoint The endpoint to be written.
+ *
+ * @return The output stream.
+ *
+ * @relates asio::local::basic_endpoint
+ */
+template <typename Elem, typename Traits, typename Protocol>
+std::basic_ostream<Elem, Traits>& operator<<(
+    std::basic_ostream<Elem, Traits>& os,
+    const basic_endpoint<Protocol>& endpoint)
+{
+  os << endpoint.path();
+  return os;
+}
+
+} // namespace local
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_LOCAL_BASIC_ENDPOINT_HPP
diff --git a/subprojects/asio/include/asio/local/connect_pair.hpp b/subprojects/asio/include/asio/local/connect_pair.hpp
new file mode 100644
index 000000000..2f7c090ed
--- /dev/null
+++ b/subprojects/asio/include/asio/local/connect_pair.hpp
@@ -0,0 +1,106 @@
+//
+// local/connect_pair.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_LOCAL_CONNECT_PAIR_HPP
+#define ASIO_LOCAL_CONNECT_PAIR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_socket.hpp"
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/local/basic_endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace local {
+
+/// Create a pair of connected sockets.
+template <typename Protocol ASIO_SVC_TPARAM ASIO_SVC_TPARAM1>
+void connect_pair(
+    basic_socket<Protocol ASIO_SVC_TARG>& socket1,
+    basic_socket<Protocol ASIO_SVC_TARG1>& socket2);
+
+/// Create a pair of connected sockets.
+template <typename Protocol ASIO_SVC_TPARAM ASIO_SVC_TPARAM1>
+ASIO_SYNC_OP_VOID connect_pair(
+    basic_socket<Protocol ASIO_SVC_TARG>& socket1,
+    basic_socket<Protocol ASIO_SVC_TARG1>& socket2,
+    asio::error_code& ec);
+
+template <typename Protocol ASIO_SVC_TPARAM ASIO_SVC_TPARAM1>
+inline void connect_pair(
+    basic_socket<Protocol ASIO_SVC_TARG>& socket1,
+    basic_socket<Protocol ASIO_SVC_TARG1>& socket2)
+{
+  asio::error_code ec;
+  connect_pair(socket1, socket2, ec);
+  asio::detail::throw_error(ec, "connect_pair");
+}
+
+template <typename Protocol ASIO_SVC_TPARAM ASIO_SVC_TPARAM1>
+inline ASIO_SYNC_OP_VOID connect_pair(
+    basic_socket<Protocol ASIO_SVC_TARG>& socket1,
+    basic_socket<Protocol ASIO_SVC_TARG1>& socket2,
+    asio::error_code& ec)
+{
+  // Check that this function is only being used with a UNIX domain socket.
+  asio::local::basic_endpoint<Protocol>* tmp
+    = static_cast<typename Protocol::endpoint*>(0);
+  (void)tmp;
+
+  Protocol protocol;
+  asio::detail::socket_type sv[2];
+  if (asio::detail::socket_ops::socketpair(protocol.family(),
+        protocol.type(), protocol.protocol(), sv, ec)
+      == asio::detail::socket_error_retval)
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+
+  socket1.assign(protocol, sv[0], ec);
+  if (ec)
+  {
+    asio::error_code temp_ec;
+    asio::detail::socket_ops::state_type state[2] = { 0, 0 };
+    asio::detail::socket_ops::close(sv[0], state[0], true, temp_ec);
+    asio::detail::socket_ops::close(sv[1], state[1], true, temp_ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  socket2.assign(protocol, sv[1], ec);
+  if (ec)
+  {
+    asio::error_code temp_ec;
+    socket1.close(temp_ec);
+    asio::detail::socket_ops::state_type state = 0;
+    asio::detail::socket_ops::close(sv[1], state, true, temp_ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+} // namespace local
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_LOCAL_CONNECT_PAIR_HPP
diff --git a/subprojects/asio/include/asio/local/datagram_protocol.hpp b/subprojects/asio/include/asio/local/datagram_protocol.hpp
new file mode 100644
index 000000000..b87df2e56
--- /dev/null
+++ b/subprojects/asio/include/asio/local/datagram_protocol.hpp
@@ -0,0 +1,80 @@
+//
+// local/datagram_protocol.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_LOCAL_DATAGRAM_PROTOCOL_HPP
+#define ASIO_LOCAL_DATAGRAM_PROTOCOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_datagram_socket.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/local/basic_endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace local {
+
+/// Encapsulates the flags needed for datagram-oriented UNIX sockets.
+/**
+ * The asio::local::datagram_protocol class contains flags necessary for
+ * datagram-oriented UNIX domain sockets.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol.
+ */
+class datagram_protocol
+{
+public:
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return SOCK_DGRAM;
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return 0;
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return AF_UNIX;
+  }
+
+  /// The type of a UNIX domain endpoint.
+  typedef basic_endpoint<datagram_protocol> endpoint;
+
+  /// The UNIX domain socket type.
+  typedef basic_datagram_socket<datagram_protocol> socket;
+};
+
+} // namespace local
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_LOCAL_DATAGRAM_PROTOCOL_HPP
diff --git a/subprojects/asio/include/asio/local/detail/endpoint.hpp b/subprojects/asio/include/asio/local/detail/endpoint.hpp
new file mode 100644
index 000000000..4870f3b9a
--- /dev/null
+++ b/subprojects/asio/include/asio/local/detail/endpoint.hpp
@@ -0,0 +1,133 @@
+//
+// local/detail/endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Derived from a public domain implementation written by Daniel Casimiro.
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_LOCAL_DETAIL_ENDPOINT_HPP
+#define ASIO_LOCAL_DETAIL_ENDPOINT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS)
+
+#include <cstddef>
+#include <string>
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace local {
+namespace detail {
+
+// Helper class for implementing a UNIX domain endpoint.
+class endpoint
+{
+public:
+  // Default constructor.
+  ASIO_DECL endpoint();
+
+  // Construct an endpoint using the specified path name.
+  ASIO_DECL endpoint(const char* path_name);
+
+  // Construct an endpoint using the specified path name.
+  ASIO_DECL endpoint(const std::string& path_name);
+
+  // Copy constructor.
+  endpoint(const endpoint& other)
+    : data_(other.data_),
+      path_length_(other.path_length_)
+  {
+  }
+
+  // Assign from another endpoint.
+  endpoint& operator=(const endpoint& other)
+  {
+    data_ = other.data_;
+    path_length_ = other.path_length_;
+    return *this;
+  }
+
+  // Get the underlying endpoint in the native type.
+  asio::detail::socket_addr_type* data()
+  {
+    return &data_.base;
+  }
+
+  // Get the underlying endpoint in the native type.
+  const asio::detail::socket_addr_type* data() const
+  {
+    return &data_.base;
+  }
+
+  // Get the underlying size of the endpoint in the native type.
+  std::size_t size() const
+  {
+    return path_length_
+      + offsetof(asio::detail::sockaddr_un_type, sun_path);
+  }
+
+  // Set the underlying size of the endpoint in the native type.
+  ASIO_DECL void resize(std::size_t size);
+
+  // Get the capacity of the endpoint in the native type.
+  std::size_t capacity() const
+  {
+    return sizeof(asio::detail::sockaddr_un_type);
+  }
+
+  // Get the path associated with the endpoint.
+  ASIO_DECL std::string path() const;
+
+  // Set the path associated with the endpoint.
+  ASIO_DECL void path(const char* p);
+
+  // Set the path associated with the endpoint.
+  ASIO_DECL void path(const std::string& p);
+
+  // Compare two endpoints for equality.
+  ASIO_DECL friend bool operator==(
+      const endpoint& e1, const endpoint& e2);
+
+  // Compare endpoints for ordering.
+  ASIO_DECL friend bool operator<(
+      const endpoint& e1, const endpoint& e2);
+
+private:
+  // The underlying UNIX socket address.
+  union data_union
+  {
+    asio::detail::socket_addr_type base;
+    asio::detail::sockaddr_un_type local;
+  } data_;
+
+  // The length of the path associated with the endpoint.
+  std::size_t path_length_;
+
+  // Initialise with a specified path.
+  ASIO_DECL void init(const char* path, std::size_t path_length);
+};
+
+} // namespace detail
+} // namespace local
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/local/detail/impl/endpoint.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)
+
+#endif // ASIO_LOCAL_DETAIL_ENDPOINT_HPP
diff --git a/subprojects/asio/include/asio/local/detail/impl/endpoint.ipp b/subprojects/asio/include/asio/local/detail/impl/endpoint.ipp
new file mode 100644
index 000000000..d5bbf503c
--- /dev/null
+++ b/subprojects/asio/include/asio/local/detail/impl/endpoint.ipp
@@ -0,0 +1,129 @@
+//
+// local/detail/impl/endpoint.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Derived from a public domain implementation written by Daniel Casimiro.
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_LOCAL_DETAIL_IMPL_ENDPOINT_IPP
+#define ASIO_LOCAL_DETAIL_IMPL_ENDPOINT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS)
+
+#include <cstring>
+#include "asio/detail/socket_ops.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/local/detail/endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace local {
+namespace detail {
+
+endpoint::endpoint()
+{
+  init("", 0);
+}
+
+endpoint::endpoint(const char* path_name)
+{
+  using namespace std; // For strlen.
+  init(path_name, strlen(path_name));
+}
+
+endpoint::endpoint(const std::string& path_name)
+{
+  init(path_name.data(), path_name.length());
+}
+
+void endpoint::resize(std::size_t new_size)
+{
+  if (new_size > sizeof(asio::detail::sockaddr_un_type))
+  {
+    asio::error_code ec(asio::error::invalid_argument);
+    asio::detail::throw_error(ec);
+  }
+  else if (new_size == 0)
+  {
+    path_length_ = 0;
+  }
+  else
+  {
+    path_length_ = new_size
+      - offsetof(asio::detail::sockaddr_un_type, sun_path);
+
+    // The path returned by the operating system may be NUL-terminated.
+    if (path_length_ > 0 && data_.local.sun_path[path_length_ - 1] == 0)
+      --path_length_;
+  }
+}
+
+std::string endpoint::path() const
+{
+  return std::string(data_.local.sun_path, path_length_);
+}
+
+void endpoint::path(const char* p)
+{
+  using namespace std; // For strlen.
+  init(p, strlen(p));
+}
+
+void endpoint::path(const std::string& p)
+{
+  init(p.data(), p.length());
+}
+
+bool operator==(const endpoint& e1, const endpoint& e2)
+{
+  return e1.path() == e2.path();
+}
+
+bool operator<(const endpoint& e1, const endpoint& e2)
+{
+  return e1.path() < e2.path();
+}
+
+void endpoint::init(const char* path_name, std::size_t path_length)
+{
+  if (path_length > sizeof(data_.local.sun_path) - 1)
+  {
+    // The buffer is not large enough to store this address.
+    asio::error_code ec(asio::error::name_too_long);
+    asio::detail::throw_error(ec);
+  }
+
+  using namespace std; // For memcpy.
+  data_.local = asio::detail::sockaddr_un_type();
+  data_.local.sun_family = AF_UNIX;
+  if (path_length > 0)
+    memcpy(data_.local.sun_path, path_name, path_length);
+  path_length_ = path_length;
+
+  // NUL-terminate normal path names. Names that start with a NUL are in the
+  // UNIX domain protocol's "abstract namespace" and are not NUL-terminated.
+  if (path_length > 0 && data_.local.sun_path[0] == 0)
+    data_.local.sun_path[path_length] = 0;
+}
+
+} // namespace detail
+} // namespace local
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)
+
+#endif // ASIO_LOCAL_DETAIL_IMPL_ENDPOINT_IPP
diff --git a/subprojects/asio/include/asio/local/stream_protocol.hpp b/subprojects/asio/include/asio/local/stream_protocol.hpp
new file mode 100644
index 000000000..e2ef5f3b9
--- /dev/null
+++ b/subprojects/asio/include/asio/local/stream_protocol.hpp
@@ -0,0 +1,90 @@
+//
+// local/stream_protocol.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_LOCAL_STREAM_PROTOCOL_HPP
+#define ASIO_LOCAL_STREAM_PROTOCOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_LOCAL_SOCKETS) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_socket_acceptor.hpp"
+#include "asio/basic_socket_iostream.hpp"
+#include "asio/basic_stream_socket.hpp"
+#include "asio/detail/socket_types.hpp"
+#include "asio/local/basic_endpoint.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace local {
+
+/// Encapsulates the flags needed for stream-oriented UNIX sockets.
+/**
+ * The asio::local::stream_protocol class contains flags necessary for
+ * stream-oriented UNIX domain sockets.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Safe.
+ *
+ * @par Concepts:
+ * Protocol.
+ */
+class stream_protocol
+{
+public:
+  /// Obtain an identifier for the type of the protocol.
+  int type() const
+  {
+    return SOCK_STREAM;
+  }
+
+  /// Obtain an identifier for the protocol.
+  int protocol() const
+  {
+    return 0;
+  }
+
+  /// Obtain an identifier for the protocol family.
+  int family() const
+  {
+    return AF_UNIX;
+  }
+
+  /// The type of a UNIX domain endpoint.
+  typedef basic_endpoint<stream_protocol> endpoint;
+
+  /// The UNIX domain socket type.
+  typedef basic_stream_socket<stream_protocol> socket;
+
+  /// The UNIX domain acceptor type.
+  typedef basic_socket_acceptor<stream_protocol> acceptor;
+
+#if !defined(ASIO_NO_IOSTREAM)
+  /// The UNIX domain iostream type.
+  typedef basic_socket_iostream<stream_protocol> iostream;
+#endif // !defined(ASIO_NO_IOSTREAM)
+};
+
+} // namespace local
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_LOCAL_SOCKETS)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_LOCAL_STREAM_PROTOCOL_HPP
diff --git a/subprojects/asio/include/asio/packaged_task.hpp b/subprojects/asio/include/asio/packaged_task.hpp
new file mode 100644
index 000000000..29b15b880
--- /dev/null
+++ b/subprojects/asio/include/asio/packaged_task.hpp
@@ -0,0 +1,126 @@
+//
+// packaged_task.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_PACKAGED_TASK_HPP
+#define ASIO_PACKAGED_TASK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/future.hpp"
+
+#if defined(ASIO_HAS_STD_FUTURE_CLASS) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/detail/variadic_templates.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if defined(ASIO_HAS_VARIADIC_TEMPLATES) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Partial specialisation of @c async_result for @c std::packaged_task.
+template <typename Result, typename... Args, typename Signature>
+class async_result<std::packaged_task<Result(Args...)>, Signature>
+{
+public:
+  /// The packaged task is the concrete completion handler type.
+  typedef std::packaged_task<Result(Args...)> completion_handler_type;
+
+  /// The return type of the initiating function is the future obtained from
+  /// the packaged task.
+  typedef std::future<Result> return_type;
+
+  /// The constructor extracts the future from the packaged task.
+  explicit async_result(completion_handler_type& h)
+    : future_(h.get_future())
+  {
+  }
+
+  /// Returns the packaged task's future.
+  return_type get()
+  {
+    return std::move(future_);
+  }
+
+private:
+  return_type future_;
+};
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+      //   || defined(GENERATING_DOCUMENTATION)
+
+template <typename Result, typename Signature>
+struct async_result<std::packaged_task<Result()>, Signature>
+{
+  typedef std::packaged_task<Result()> completion_handler_type;
+  typedef std::future<Result> return_type;
+
+  explicit async_result(completion_handler_type& h)
+    : future_(h.get_future())
+  {
+  }
+
+  return_type get()
+  {
+    return std::move(future_);
+  }
+
+private:
+  return_type future_;
+};
+
+#define ASIO_PRIVATE_ASYNC_RESULT_DEF(n) \
+  template <typename Result, \
+    ASIO_VARIADIC_TPARAMS(n), typename Signature> \
+  class async_result< \
+    std::packaged_task<Result(ASIO_VARIADIC_TARGS(n))>, Signature> \
+  { \
+  public: \
+    typedef std::packaged_task< \
+      Result(ASIO_VARIADIC_TARGS(n))> \
+        completion_handler_type; \
+  \
+    typedef std::future<Result> return_type; \
+  \
+    explicit async_result(completion_handler_type& h) \
+      : future_(h.get_future()) \
+    { \
+    } \
+  \
+    return_type get() \
+    { \
+      return std::move(future_); \
+    } \
+  \
+  private: \
+    return_type future_; \
+  }; \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_RESULT_DEF)
+#undef ASIO_PRIVATE_ASYNC_RESULT_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_STD_FUTURE_CLASS)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_PACKAGED_TASK_HPP
diff --git a/subprojects/asio/include/asio/placeholders.hpp b/subprojects/asio/include/asio/placeholders.hpp
new file mode 100644
index 000000000..e71a21e7f
--- /dev/null
+++ b/subprojects/asio/include/asio/placeholders.hpp
@@ -0,0 +1,151 @@
+//
+// placeholders.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_PLACEHOLDERS_HPP
+#define ASIO_PLACEHOLDERS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_BIND)
+# include <boost/bind/arg.hpp>
+#endif // defined(ASIO_HAS_BOOST_BIND)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace placeholders {
+
+#if defined(GENERATING_DOCUMENTATION)
+
+/// An argument placeholder, for use with boost::bind(), that corresponds to
+/// the error argument of a handler for any of the asynchronous functions.
+unspecified error;
+
+/// An argument placeholder, for use with boost::bind(), that corresponds to
+/// the bytes_transferred argument of a handler for asynchronous functions such
+/// as asio::basic_stream_socket::async_write_some or
+/// asio::async_write.
+unspecified bytes_transferred;
+
+/// An argument placeholder, for use with boost::bind(), that corresponds to
+/// the iterator argument of a handler for asynchronous functions such as
+/// asio::async_connect.
+unspecified iterator;
+
+/// An argument placeholder, for use with boost::bind(), that corresponds to
+/// the results argument of a handler for asynchronous functions such as
+/// asio::basic_resolver::async_resolve.
+unspecified results;
+
+/// An argument placeholder, for use with boost::bind(), that corresponds to
+/// the results argument of a handler for asynchronous functions such as
+/// asio::async_connect.
+unspecified endpoint;
+
+/// An argument placeholder, for use with boost::bind(), that corresponds to
+/// the signal_number argument of a handler for asynchronous functions such as
+/// asio::signal_set::async_wait.
+unspecified signal_number;
+
+#elif defined(ASIO_HAS_BOOST_BIND)
+# if defined(__BORLANDC__) || defined(__GNUC__)
+
+inline boost::arg<1> error()
+{
+  return boost::arg<1>();
+}
+
+inline boost::arg<2> bytes_transferred()
+{
+  return boost::arg<2>();
+}
+
+inline boost::arg<2> iterator()
+{
+  return boost::arg<2>();
+}
+
+inline boost::arg<2> results()
+{
+  return boost::arg<2>();
+}
+
+inline boost::arg<2> endpoint()
+{
+  return boost::arg<2>();
+}
+
+inline boost::arg<2> signal_number()
+{
+  return boost::arg<2>();
+}
+
+# else
+
+namespace detail
+{
+  template <int Number>
+  struct placeholder
+  {
+    static boost::arg<Number>& get()
+    {
+      static boost::arg<Number> result;
+      return result;
+    }
+  };
+}
+
+#  if defined(ASIO_MSVC) && (ASIO_MSVC < 1400)
+
+static boost::arg<1>& error
+  = asio::placeholders::detail::placeholder<1>::get();
+static boost::arg<2>& bytes_transferred
+  = asio::placeholders::detail::placeholder<2>::get();
+static boost::arg<2>& iterator
+  = asio::placeholders::detail::placeholder<2>::get();
+static boost::arg<2>& results
+  = asio::placeholders::detail::placeholder<2>::get();
+static boost::arg<2>& endpoint
+  = asio::placeholders::detail::placeholder<2>::get();
+static boost::arg<2>& signal_number
+  = asio::placeholders::detail::placeholder<2>::get();
+
+#  else
+
+namespace
+{
+  boost::arg<1>& error
+    = asio::placeholders::detail::placeholder<1>::get();
+  boost::arg<2>& bytes_transferred
+    = asio::placeholders::detail::placeholder<2>::get();
+  boost::arg<2>& iterator
+    = asio::placeholders::detail::placeholder<2>::get();
+  boost::arg<2>& results
+    = asio::placeholders::detail::placeholder<2>::get();
+  boost::arg<2>& endpoint
+    = asio::placeholders::detail::placeholder<2>::get();
+  boost::arg<2>& signal_number
+    = asio::placeholders::detail::placeholder<2>::get();
+} // namespace
+
+#  endif
+# endif
+#endif
+
+} // namespace placeholders
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_PLACEHOLDERS_HPP
diff --git a/subprojects/asio/include/asio/posix/basic_descriptor.hpp b/subprojects/asio/include/asio/posix/basic_descriptor.hpp
new file mode 100644
index 000000000..c15da632c
--- /dev/null
+++ b/subprojects/asio/include/asio/posix/basic_descriptor.hpp
@@ -0,0 +1,582 @@
+//
+// posix/basic_descriptor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_POSIX_BASIC_DESCRIPTOR_HPP
+#define ASIO_POSIX_BASIC_DESCRIPTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/posix/descriptor_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace posix {
+
+/// Provides POSIX descriptor functionality.
+/**
+ * The posix::basic_descriptor class template provides the ability to wrap a
+ * POSIX descriptor.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename DescriptorService>
+class basic_descriptor
+  : public basic_io_object<DescriptorService>,
+    public descriptor_base
+{
+public:
+  /// The native representation of a descriptor.
+  typedef typename DescriptorService::native_handle_type native_handle_type;
+
+  /// A basic_descriptor is always the lowest layer.
+  typedef basic_descriptor<DescriptorService> lowest_layer_type;
+
+  /// Construct a basic_descriptor without opening it.
+  /**
+   * This constructor creates a descriptor without opening it.
+   *
+   * @param io_context The io_context object that the descriptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   */
+  explicit basic_descriptor(asio::io_context& io_context)
+    : basic_io_object<DescriptorService>(io_context)
+  {
+  }
+
+  /// Construct a basic_descriptor on an existing native descriptor.
+  /**
+   * This constructor creates a descriptor object to hold an existing native
+   * descriptor.
+   *
+   * @param io_context The io_context object that the descriptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   *
+   * @param native_descriptor A native descriptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_descriptor(asio::io_context& io_context,
+      const native_handle_type& native_descriptor)
+    : basic_io_object<DescriptorService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_descriptor, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_descriptor from another.
+  /**
+   * This constructor moves a descriptor from one object to another.
+   *
+   * @param other The other basic_descriptor object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_descriptor(io_context&) constructor.
+   */
+  basic_descriptor(basic_descriptor&& other)
+    : basic_io_object<DescriptorService>(
+        ASIO_MOVE_CAST(basic_descriptor)(other))
+  {
+  }
+
+  /// Move-assign a basic_descriptor from another.
+  /**
+   * This assignment operator moves a descriptor from one object to another.
+   *
+   * @param other The other basic_descriptor object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_descriptor(io_context&) constructor.
+   */
+  basic_descriptor& operator=(basic_descriptor&& other)
+  {
+    basic_io_object<DescriptorService>::operator=(
+        ASIO_MOVE_CAST(basic_descriptor)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since a basic_descriptor cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since a basic_descriptor cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+
+  /// Assign an existing native descriptor to the descriptor.
+  /*
+   * This function opens the descriptor to hold an existing native descriptor.
+   *
+   * @param native_descriptor A native descriptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const native_handle_type& native_descriptor)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_descriptor, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native descriptor to the descriptor.
+  /*
+   * This function opens the descriptor to hold an existing native descriptor.
+   *
+   * @param native_descriptor A native descriptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const native_handle_type& native_descriptor,
+      asio::error_code& ec)
+  {
+    this->get_service().assign(
+        this->get_implementation(), native_descriptor, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the descriptor is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the descriptor.
+  /**
+   * This function is used to close the descriptor. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure. Note that, even if
+   * the function indicates an error, the underlying descriptor is closed.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the descriptor.
+  /**
+   * This function is used to close the descriptor. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any. Note that, even if
+   * the function indicates an error, the underlying descriptor is closed.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native descriptor representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * descriptor. This is intended to allow access to native descriptor
+   * functionality that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Release ownership of the native descriptor implementation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * descriptor. After calling this function, @c is_open() returns false. The
+   * caller is responsible for closing the descriptor.
+   *
+   * All outstanding asynchronous read or write operations will finish
+   * immediately, and the handlers for cancelled operations will be passed the
+   * asio::error::operation_aborted error.
+   */
+  native_handle_type release()
+  {
+    return this->get_service().release(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the descriptor.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the descriptor.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the descriptor.
+  /**
+   * This function is used to execute an IO control command on the descriptor.
+   *
+   * @param command The IO control command to be performed on the descriptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa IoControlCommand @n
+   * asio::posix::descriptor_base::bytes_readable @n
+   * asio::posix::descriptor_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * asio::posix::stream_descriptor::bytes_readable command;
+   * descriptor.io_control(command);
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  void io_control(IoControlCommand& command)
+  {
+    asio::error_code ec;
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    asio::detail::throw_error(ec, "io_control");
+  }
+
+  /// Perform an IO control command on the descriptor.
+  /**
+   * This function is used to execute an IO control command on the descriptor.
+   *
+   * @param command The IO control command to be performed on the descriptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa IoControlCommand @n
+   * asio::posix::descriptor_base::bytes_readable @n
+   * asio::posix::descriptor_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * asio::posix::stream_descriptor::bytes_readable command;
+   * asio::error_code ec;
+   * descriptor.io_control(command, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(IoControlCommand& command,
+      asio::error_code& ec)
+  {
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the descriptor.
+  /**
+   * @returns @c true if the descriptor's synchronous operations will fail with
+   * asio::error::would_block if they are unable to perform the requested
+   * operation immediately. If @c false, synchronous operations will block
+   * until complete.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  bool non_blocking() const
+  {
+    return this->get_service().non_blocking(this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the descriptor.
+  /**
+   * @param mode If @c true, the descriptor's synchronous operations will fail
+   * with asio::error::would_block if they are unable to perform the
+   * requested operation immediately. If @c false, synchronous operations will
+   * block until complete.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  void non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the descriptor.
+  /**
+   * @param mode If @c true, the descriptor's synchronous operations will fail
+   * with asio::error::would_block if they are unable to perform the
+   * requested operation immediately. If @c false, synchronous operations will
+   * block until complete.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  ASIO_SYNC_OP_VOID non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native descriptor implementation.
+  /**
+   * This function is used to retrieve the non-blocking mode of the underlying
+   * native descriptor. This mode has no effect on the behaviour of the
+   * descriptor object's synchronous operations.
+   *
+   * @returns @c true if the underlying descriptor is in non-blocking mode and
+   * direct system calls may fail with asio::error::would_block (or the
+   * equivalent system error).
+   *
+   * @note The current non-blocking mode is cached by the descriptor object.
+   * Consequently, the return value may be incorrect if the non-blocking mode
+   * was set directly on the native descriptor.
+   */
+  bool native_non_blocking() const
+  {
+    return this->get_service().native_non_blocking(
+        this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the native descriptor implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native descriptor. It has no effect on the behaviour of the descriptor
+   * object's synchronous operations.
+   *
+   * @param mode If @c true, the underlying descriptor is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @throws asio::system_error Thrown on failure. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   */
+  void native_non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "native_non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the native descriptor implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native descriptor. It has no effect on the behaviour of the descriptor
+   * object's synchronous operations.
+   *
+   * @param mode If @c true, the underlying descriptor is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @param ec Set to indicate what error occurred, if any. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   */
+  ASIO_SYNC_OP_VOID native_non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the descriptor to become ready to read, ready to write, or to
+  /// have pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for a descriptor to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired descriptor state.
+   *
+   * @par Example
+   * Waiting for a descriptor to become readable.
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * descriptor.wait(asio::posix::stream_descriptor::wait_read);
+   * @endcode
+   */
+  void wait(wait_type w)
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), w, ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Wait for the descriptor to become ready to read, ready to write, or to
+  /// have pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for a descriptor to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired descriptor state.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * Waiting for a descriptor to become readable.
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * asio::error_code ec;
+   * descriptor.wait(asio::posix::stream_descriptor::wait_read, ec);
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID wait(wait_type w, asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the descriptor to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  /**
+   * This function is used to perform an asynchronous wait for a descriptor to
+   * enter a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired descriptor state.
+   *
+   * @param handler The handler to be called when the wait operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void wait_handler(const asio::error_code& error)
+   * {
+   *   if (!error)
+   *   {
+   *     // Wait succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * descriptor.async_wait(
+   *     asio::posix::stream_descriptor::wait_read,
+   *     wait_handler);
+   * @endcode
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(wait_type w, ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WaitHandler.
+    ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
+
+    return this->get_service().async_wait(this->get_implementation(),
+        w, ASIO_MOVE_CAST(WaitHandler)(handler));
+  }
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~basic_descriptor()
+  {
+  }
+};
+
+} // namespace posix
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_POSIX_BASIC_DESCRIPTOR_HPP
diff --git a/subprojects/asio/include/asio/posix/basic_stream_descriptor.hpp b/subprojects/asio/include/asio/posix/basic_stream_descriptor.hpp
new file mode 100644
index 000000000..acd5cb6ae
--- /dev/null
+++ b/subprojects/asio/include/asio/posix/basic_stream_descriptor.hpp
@@ -0,0 +1,362 @@
+//
+// posix/basic_stream_descriptor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_HPP
+#define ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/posix/basic_descriptor.hpp"
+#include "asio/posix/stream_descriptor_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace posix {
+
+/// Provides stream-oriented descriptor functionality.
+/**
+ * The posix::basic_stream_descriptor class template provides asynchronous and
+ * blocking stream-oriented descriptor functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+template <typename StreamDescriptorService = stream_descriptor_service>
+class basic_stream_descriptor
+  : public basic_descriptor<StreamDescriptorService>
+{
+public:
+  /// The native representation of a descriptor.
+  typedef typename StreamDescriptorService::native_handle_type
+    native_handle_type;
+
+  /// Construct a basic_stream_descriptor without opening it.
+  /**
+   * This constructor creates a stream descriptor without opening it. The
+   * descriptor needs to be opened and then connected or accepted before data
+   * can be sent or received on it.
+   *
+   * @param io_context The io_context object that the stream descriptor will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   */
+  explicit basic_stream_descriptor(asio::io_context& io_context)
+    : basic_descriptor<StreamDescriptorService>(io_context)
+  {
+  }
+
+  /// Construct a basic_stream_descriptor on an existing native descriptor.
+  /**
+   * This constructor creates a stream descriptor object to hold an existing
+   * native descriptor.
+   *
+   * @param io_context The io_context object that the stream descriptor will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   *
+   * @param native_descriptor The new underlying descriptor implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_stream_descriptor(asio::io_context& io_context,
+      const native_handle_type& native_descriptor)
+    : basic_descriptor<StreamDescriptorService>(io_context, native_descriptor)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_stream_descriptor from another.
+  /**
+   * This constructor moves a stream descriptor from one object to another.
+   *
+   * @param other The other basic_stream_descriptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_descriptor(io_context&) constructor.
+   */
+  basic_stream_descriptor(basic_stream_descriptor&& other)
+    : basic_descriptor<StreamDescriptorService>(
+        ASIO_MOVE_CAST(basic_stream_descriptor)(other))
+  {
+  }
+
+  /// Move-assign a basic_stream_descriptor from another.
+  /**
+   * This assignment operator moves a stream descriptor from one object to
+   * another.
+   *
+   * @param other The other basic_stream_descriptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_descriptor(io_context&) constructor.
+   */
+  basic_stream_descriptor& operator=(basic_stream_descriptor&& other)
+  {
+    basic_descriptor<StreamDescriptorService>::operator=(
+        ASIO_MOVE_CAST(basic_stream_descriptor)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Write some data to the descriptor.
+  /**
+   * This function is used to write data to the stream descriptor. The function
+   * call will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the descriptor.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.write_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return s;
+  }
+
+  /// Write some data to the descriptor.
+  /**
+   * This function is used to write data to the stream descriptor. The function
+   * call will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the descriptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write data to the stream
+   * descriptor. The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be written to the descriptor.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.async_write_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    return this->get_service().async_write_some(this->get_implementation(),
+        buffers, ASIO_MOVE_CAST(WriteHandler)(handler));
+  }
+
+  /// Read some data from the descriptor.
+  /**
+   * This function is used to read data from the stream descriptor. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.read_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return s;
+  }
+
+  /// Read some data from the descriptor.
+  /**
+   * This function is used to read data from the stream descriptor. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read data from the stream
+   * descriptor. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read function if you need to ensure that the
+   * requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.async_read_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    return this->get_service().async_read_some(this->get_implementation(),
+        buffers, ASIO_MOVE_CAST(ReadHandler)(handler));
+  }
+};
+
+} // namespace posix
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_HPP
diff --git a/subprojects/asio/include/asio/posix/descriptor.hpp b/subprojects/asio/include/asio/posix/descriptor.hpp
new file mode 100644
index 000000000..d0cee1a26
--- /dev/null
+++ b/subprojects/asio/include/asio/posix/descriptor.hpp
@@ -0,0 +1,644 @@
+//
+// posix/descriptor.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_POSIX_DESCRIPTOR_HPP
+#define ASIO_POSIX_DESCRIPTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/async_result.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/reactive_descriptor_service.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/posix/descriptor_base.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#define ASIO_SVC_T asio::detail::reactive_descriptor_service
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace posix {
+
+/// Provides POSIX descriptor functionality.
+/**
+ * The posix::descriptor class template provides the ability to wrap a
+ * POSIX descriptor.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class descriptor
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>,
+    public descriptor_base
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The native representation of a descriptor.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef ASIO_SVC_T::native_handle_type native_handle_type;
+#endif
+
+  /// A descriptor is always the lowest layer.
+  typedef descriptor lowest_layer_type;
+
+  /// Construct a descriptor without opening it.
+  /**
+   * This constructor creates a descriptor without opening it.
+   *
+   * @param io_context The io_context object that the descriptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   */
+  explicit descriptor(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Construct a descriptor on an existing native descriptor.
+  /**
+   * This constructor creates a descriptor object to hold an existing native
+   * descriptor.
+   *
+   * @param io_context The io_context object that the descriptor will use to
+   * dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   *
+   * @param native_descriptor A native descriptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  descriptor(asio::io_context& io_context,
+      const native_handle_type& native_descriptor)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_descriptor, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a descriptor from another.
+  /**
+   * This constructor moves a descriptor from one object to another.
+   *
+   * @param other The other descriptor object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c descriptor(io_context&) constructor.
+   */
+  descriptor(descriptor&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign a descriptor from another.
+  /**
+   * This assignment operator moves a descriptor from one object to another.
+   *
+   * @param other The other descriptor object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c descriptor(io_context&) constructor.
+   */
+  descriptor& operator=(descriptor&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since a descriptor cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since a descriptor cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+
+  /// Assign an existing native descriptor to the descriptor.
+  /*
+   * This function opens the descriptor to hold an existing native descriptor.
+   *
+   * @param native_descriptor A native descriptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const native_handle_type& native_descriptor)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_descriptor, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native descriptor to the descriptor.
+  /*
+   * This function opens the descriptor to hold an existing native descriptor.
+   *
+   * @param native_descriptor A native descriptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const native_handle_type& native_descriptor,
+      asio::error_code& ec)
+  {
+    this->get_service().assign(
+        this->get_implementation(), native_descriptor, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the descriptor is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the descriptor.
+  /**
+   * This function is used to close the descriptor. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure. Note that, even if
+   * the function indicates an error, the underlying descriptor is closed.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the descriptor.
+  /**
+   * This function is used to close the descriptor. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any. Note that, even if
+   * the function indicates an error, the underlying descriptor is closed.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native descriptor representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * descriptor. This is intended to allow access to native descriptor
+   * functionality that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Release ownership of the native descriptor implementation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * descriptor. After calling this function, @c is_open() returns false. The
+   * caller is responsible for closing the descriptor.
+   *
+   * All outstanding asynchronous read or write operations will finish
+   * immediately, and the handlers for cancelled operations will be passed the
+   * asio::error::operation_aborted error.
+   */
+  native_handle_type release()
+  {
+    return this->get_service().release(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the descriptor.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the descriptor.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the descriptor.
+  /**
+   * This function is used to execute an IO control command on the descriptor.
+   *
+   * @param command The IO control command to be performed on the descriptor.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa IoControlCommand @n
+   * asio::posix::descriptor_base::bytes_readable @n
+   * asio::posix::descriptor_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * asio::posix::stream_descriptor::bytes_readable command;
+   * descriptor.io_control(command);
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  void io_control(IoControlCommand& command)
+  {
+    asio::error_code ec;
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    asio::detail::throw_error(ec, "io_control");
+  }
+
+  /// Perform an IO control command on the descriptor.
+  /**
+   * This function is used to execute an IO control command on the descriptor.
+   *
+   * @param command The IO control command to be performed on the descriptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa IoControlCommand @n
+   * asio::posix::descriptor_base::bytes_readable @n
+   * asio::posix::descriptor_base::non_blocking_io
+   *
+   * @par Example
+   * Getting the number of bytes ready to read:
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * asio::posix::stream_descriptor::bytes_readable command;
+   * asio::error_code ec;
+   * descriptor.io_control(command, ec);
+   * if (ec)
+   * {
+   *   // An error occurred.
+   * }
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   */
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(IoControlCommand& command,
+      asio::error_code& ec)
+  {
+    this->get_service().io_control(this->get_implementation(), command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the descriptor.
+  /**
+   * @returns @c true if the descriptor's synchronous operations will fail with
+   * asio::error::would_block if they are unable to perform the requested
+   * operation immediately. If @c false, synchronous operations will block
+   * until complete.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  bool non_blocking() const
+  {
+    return this->get_service().non_blocking(this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the descriptor.
+  /**
+   * @param mode If @c true, the descriptor's synchronous operations will fail
+   * with asio::error::would_block if they are unable to perform the
+   * requested operation immediately. If @c false, synchronous operations will
+   * block until complete.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  void non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the descriptor.
+  /**
+   * @param mode If @c true, the descriptor's synchronous operations will fail
+   * with asio::error::would_block if they are unable to perform the
+   * requested operation immediately. If @c false, synchronous operations will
+   * block until complete.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note The non-blocking mode has no effect on the behaviour of asynchronous
+   * operations. Asynchronous operations will never fail with the error
+   * asio::error::would_block.
+   */
+  ASIO_SYNC_OP_VOID non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().non_blocking(this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native descriptor implementation.
+  /**
+   * This function is used to retrieve the non-blocking mode of the underlying
+   * native descriptor. This mode has no effect on the behaviour of the
+   * descriptor object's synchronous operations.
+   *
+   * @returns @c true if the underlying descriptor is in non-blocking mode and
+   * direct system calls may fail with asio::error::would_block (or the
+   * equivalent system error).
+   *
+   * @note The current non-blocking mode is cached by the descriptor object.
+   * Consequently, the return value may be incorrect if the non-blocking mode
+   * was set directly on the native descriptor.
+   */
+  bool native_non_blocking() const
+  {
+    return this->get_service().native_non_blocking(
+        this->get_implementation());
+  }
+
+  /// Sets the non-blocking mode of the native descriptor implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native descriptor. It has no effect on the behaviour of the descriptor
+   * object's synchronous operations.
+   *
+   * @param mode If @c true, the underlying descriptor is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @throws asio::system_error Thrown on failure. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   */
+  void native_non_blocking(bool mode)
+  {
+    asio::error_code ec;
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    asio::detail::throw_error(ec, "native_non_blocking");
+  }
+
+  /// Sets the non-blocking mode of the native descriptor implementation.
+  /**
+   * This function is used to modify the non-blocking mode of the underlying
+   * native descriptor. It has no effect on the behaviour of the descriptor
+   * object's synchronous operations.
+   *
+   * @param mode If @c true, the underlying descriptor is put into non-blocking
+   * mode and direct system calls may fail with asio::error::would_block
+   * (or the equivalent system error).
+   *
+   * @param ec Set to indicate what error occurred, if any. If the @c mode is
+   * @c false, but the current value of @c non_blocking() is @c true, this
+   * function fails with asio::error::invalid_argument, as the
+   * combination does not make sense.
+   */
+  ASIO_SYNC_OP_VOID native_non_blocking(
+      bool mode, asio::error_code& ec)
+  {
+    this->get_service().native_non_blocking(
+        this->get_implementation(), mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the descriptor to become ready to read, ready to write, or to
+  /// have pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for a descriptor to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired descriptor state.
+   *
+   * @par Example
+   * Waiting for a descriptor to become readable.
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * descriptor.wait(asio::posix::stream_descriptor::wait_read);
+   * @endcode
+   */
+  void wait(wait_type w)
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), w, ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Wait for the descriptor to become ready to read, ready to write, or to
+  /// have pending error conditions.
+  /**
+   * This function is used to perform a blocking wait for a descriptor to enter
+   * a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired descriptor state.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @par Example
+   * Waiting for a descriptor to become readable.
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * asio::error_code ec;
+   * descriptor.wait(asio::posix::stream_descriptor::wait_read, ec);
+   * @endcode
+   */
+  ASIO_SYNC_OP_VOID wait(wait_type w, asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the descriptor to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  /**
+   * This function is used to perform an asynchronous wait for a descriptor to
+   * enter a ready to read, write or error condition state.
+   *
+   * @param w Specifies the desired descriptor state.
+   *
+   * @param handler The handler to be called when the wait operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @par Example
+   * @code
+   * void wait_handler(const asio::error_code& error)
+   * {
+   *   if (!error)
+   *   {
+   *     // Wait succeeded.
+   *   }
+   * }
+   *
+   * ...
+   *
+   * asio::posix::stream_descriptor descriptor(io_context);
+   * ...
+   * descriptor.async_wait(
+   *     asio::posix::stream_descriptor::wait_read,
+   *     wait_handler);
+   * @endcode
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(wait_type w, ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WaitHandler.
+    ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
+
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_wait(
+        this->get_implementation(), w, init.completion_handler);
+
+    return init.result.get();
+  }
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  /**
+   * This function destroys the descriptor, cancelling any outstanding
+   * asynchronous wait operations associated with the descriptor as if by
+   * calling @c cancel.
+   */
+  ~descriptor()
+  {
+  }
+};
+
+} // namespace posix
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#undef ASIO_SVC_T
+
+#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_POSIX_DESCRIPTOR_HPP
diff --git a/subprojects/asio/include/asio/posix/descriptor_base.hpp b/subprojects/asio/include/asio/posix/descriptor_base.hpp
new file mode 100644
index 000000000..4aac04f10
--- /dev/null
+++ b/subprojects/asio/include/asio/posix/descriptor_base.hpp
@@ -0,0 +1,90 @@
+//
+// posix/descriptor_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_POSIX_DESCRIPTOR_BASE_HPP
+#define ASIO_POSIX_DESCRIPTOR_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/detail/io_control.hpp"
+#include "asio/detail/socket_option.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace posix {
+
+/// The descriptor_base class is used as a base for the descriptor class as a
+/// place to define the associated IO control commands.
+class descriptor_base
+{
+public:
+  /// Wait types.
+  /**
+   * For use with descriptor::wait() and descriptor::async_wait().
+   */
+  enum wait_type
+  {
+    /// Wait for a descriptor to become ready to read.
+    wait_read,
+
+    /// Wait for a descriptor to become ready to write.
+    wait_write,
+
+    /// Wait for a descriptor to have error conditions pending.
+    wait_error
+  };
+
+  /// IO control command to get the amount of data that can be read without
+  /// blocking.
+  /**
+   * Implements the FIONREAD IO control command.
+   *
+   * @par Example
+   * @code
+   * asio::posix::stream_descriptor descriptor(io_context); 
+   * ...
+   * asio::descriptor_base::bytes_readable command(true);
+   * descriptor.io_control(command);
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   *
+   * @par Concepts:
+   * IoControlCommand.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined bytes_readable;
+#else
+  typedef asio::detail::io_control::bytes_readable bytes_readable;
+#endif
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~descriptor_base()
+  {
+  }
+};
+
+} // namespace posix
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_POSIX_DESCRIPTOR_BASE_HPP
diff --git a/subprojects/asio/include/asio/posix/stream_descriptor.hpp b/subprojects/asio/include/asio/posix/stream_descriptor.hpp
new file mode 100644
index 000000000..abb426a39
--- /dev/null
+++ b/subprojects/asio/include/asio/posix/stream_descriptor.hpp
@@ -0,0 +1,360 @@
+//
+// posix/stream_descriptor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_POSIX_STREAM_DESCRIPTOR_HPP
+#define ASIO_POSIX_STREAM_DESCRIPTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/posix/descriptor.hpp"
+
+#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/posix/basic_stream_descriptor.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+namespace asio {
+namespace posix {
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+// Typedef for the typical usage of a stream-oriented descriptor.
+typedef basic_stream_descriptor<> stream_descriptor;
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+/// Provides stream-oriented descriptor functionality.
+/**
+ * The posix::stream_descriptor class template provides asynchronous and
+ * blocking stream-oriented descriptor functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+class stream_descriptor
+  : public descriptor
+{
+public:
+  /// Construct a stream_descriptor without opening it.
+  /**
+   * This constructor creates a stream descriptor without opening it. The
+   * descriptor needs to be opened and then connected or accepted before data
+   * can be sent or received on it.
+   *
+   * @param io_context The io_context object that the stream descriptor will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   */
+  explicit stream_descriptor(asio::io_context& io_context)
+    : descriptor(io_context)
+  {
+  }
+
+  /// Construct a stream_descriptor on an existing native descriptor.
+  /**
+   * This constructor creates a stream descriptor object to hold an existing
+   * native descriptor.
+   *
+   * @param io_context The io_context object that the stream descriptor will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * descriptor.
+   *
+   * @param native_descriptor The new underlying descriptor implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  stream_descriptor(asio::io_context& io_context,
+      const native_handle_type& native_descriptor)
+    : descriptor(io_context, native_descriptor)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a stream_descriptor from another.
+  /**
+   * This constructor moves a stream descriptor from one object to another.
+   *
+   * @param other The other stream_descriptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c stream_descriptor(io_context&) constructor.
+   */
+  stream_descriptor(stream_descriptor&& other)
+    : descriptor(std::move(other))
+  {
+  }
+
+  /// Move-assign a stream_descriptor from another.
+  /**
+   * This assignment operator moves a stream descriptor from one object to
+   * another.
+   *
+   * @param other The other stream_descriptor object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c stream_descriptor(io_context&) constructor.
+   */
+  stream_descriptor& operator=(stream_descriptor&& other)
+  {
+    descriptor::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Write some data to the descriptor.
+  /**
+   * This function is used to write data to the stream descriptor. The function
+   * call will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the descriptor.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.write_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return s;
+  }
+
+  /// Write some data to the descriptor.
+  /**
+   * This function is used to write data to the stream descriptor. The function
+   * call will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the descriptor.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write data to the stream
+   * descriptor. The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be written to the descriptor.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.async_write_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    asio::async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_write_some(
+        this->get_implementation(), buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the descriptor.
+  /**
+   * This function is used to read data from the stream descriptor. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.read_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return s;
+  }
+
+  /// Read some data from the descriptor.
+  /**
+   * This function is used to read data from the stream descriptor. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read data from the stream
+   * descriptor. The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read function if you need to ensure that the
+   * requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * descriptor.async_read_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    asio::async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_read_some(
+        this->get_implementation(), buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+};
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+} // namespace posix
+} // namespace asio
+
+#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_POSIX_STREAM_DESCRIPTOR_HPP
diff --git a/subprojects/asio/include/asio/posix/stream_descriptor_service.hpp b/subprojects/asio/include/asio/posix/stream_descriptor_service.hpp
new file mode 100644
index 000000000..4ffbb9602
--- /dev/null
+++ b/subprojects/asio/include/asio/posix/stream_descriptor_service.hpp
@@ -0,0 +1,279 @@
+//
+// posix/stream_descriptor_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_POSIX_STREAM_DESCRIPTOR_SERVICE_HPP
+#define ASIO_POSIX_STREAM_DESCRIPTOR_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/detail/reactive_descriptor_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace posix {
+
+/// Default service implementation for a stream descriptor.
+class stream_descriptor_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<stream_descriptor_service>
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+private:
+  // The type of the platform-specific implementation.
+  typedef detail::reactive_descriptor_service service_impl_type;
+
+public:
+  /// The type of a stream descriptor implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native descriptor type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new stream descriptor service for the specified io_context.
+  explicit stream_descriptor_service(asio::io_context& io_context)
+    : asio::detail::service_base<stream_descriptor_service>(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new stream descriptor implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new stream descriptor implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another stream descriptor implementation.
+  void move_assign(implementation_type& impl,
+      stream_descriptor_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a stream descriptor implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Assign an existing native descriptor to a stream descriptor.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const native_handle_type& native_descriptor,
+      asio::error_code& ec)
+  {
+    service_impl_.assign(impl, native_descriptor, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the descriptor is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a stream descriptor implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native descriptor implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Release ownership of the native descriptor implementation.
+  native_handle_type release(implementation_type& impl)
+  {
+    return service_impl_.release(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the descriptor.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the descriptor.
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(implementation_type& impl,
+      IoControlCommand& command, asio::error_code& ec)
+  {
+    service_impl_.io_control(impl, command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the descriptor.
+  bool non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the descriptor.
+  ASIO_SYNC_OP_VOID non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native descriptor implementation.
+  bool native_non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.native_non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the native descriptor implementation.
+  ASIO_SYNC_OP_VOID native_non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.native_non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the descriptor to become ready to read, ready to write, or to
+  /// have pending error conditions.
+  ASIO_SYNC_OP_VOID wait(implementation_type& impl,
+      descriptor_base::wait_type w, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the descriptor to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl, descriptor_base::wait_type w,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, w, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Write the given data to the stream.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.write_some(impl, buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    asio::async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_write_some(impl, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the stream.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.read_some(impl, buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    asio::async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_read_some(impl, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace posix
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_POSIX_STREAM_DESCRIPTOR_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/post.hpp b/subprojects/asio/include/asio/post.hpp
new file mode 100644
index 000000000..87d7b96d6
--- /dev/null
+++ b/subprojects/asio/include/asio/post.hpp
@@ -0,0 +1,107 @@
+//
+// post.hpp
+// ~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_POST_HPP
+#define ASIO_POST_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/is_executor.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Submits a completion token or function object for execution.
+/**
+ * This function submits an object for execution using the object's associated
+ * executor. The function object is queued for execution, and is never called
+ * from the current thread prior to returning from <tt>post()</tt>.
+ *
+ * This function has the following effects:
+ *
+ * @li Constructs a function object handler of type @c Handler, initialized
+ * with <tt>handler(forward<CompletionToken>(token))</tt>.
+ *
+ * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
+ * initializing the object as <tt>result(handler)</tt>.
+ *
+ * @li Obtains the handler's associated executor object @c ex by performing
+ * <tt>get_associated_executor(handler)</tt>.
+ *
+ * @li Obtains the handler's associated allocator object @c alloc by performing
+ * <tt>get_associated_allocator(handler)</tt>.
+ *
+ * @li Performs <tt>ex.post(std::move(handler), alloc)</tt>.
+ *
+ * @li Returns <tt>result.get()</tt>.
+ */
+template <typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) post(
+    ASIO_MOVE_ARG(CompletionToken) token);
+
+/// Submits a completion token or function object for execution.
+/**
+ * This function submits an object for execution using the specified executor.
+ * The function object is queued for execution, and is never called from the
+ * current thread prior to returning from <tt>post()</tt>.
+ *
+ * This function has the following effects:
+ *
+ * @li Constructs a function object handler of type @c Handler, initialized
+ * with <tt>handler(forward<CompletionToken>(token))</tt>.
+ *
+ * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
+ * initializing the object as <tt>result(handler)</tt>.
+ *
+ * @li Obtains the handler's associated executor object @c ex1 by performing
+ * <tt>get_associated_executor(handler)</tt>.
+ *
+ * @li Creates a work object @c w by performing <tt>make_work(ex1)</tt>.
+ *
+ * @li Obtains the handler's associated allocator object @c alloc by performing
+ * <tt>get_associated_allocator(handler)</tt>.
+ *
+ * @li Constructs a function object @c f with a function call operator that
+ * performs <tt>ex1.dispatch(std::move(handler), alloc)</tt> followed by
+ * <tt>w.reset()</tt>.
+ *
+ * @li Performs <tt>Executor(ex).post(std::move(f), alloc)</tt>.
+ *
+ * @li Returns <tt>result.get()</tt>.
+ */
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) post(
+    const Executor& ex, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_executor<Executor>::value>::type* = 0);
+
+/// Submits a completion token or function object for execution.
+/**
+ * @returns <tt>post(ctx.get_executor(), forward<CompletionToken>(token))</tt>.
+ */
+template <typename ExecutionContext, typename CompletionToken>
+ASIO_INITFN_RESULT_TYPE(CompletionToken, void()) post(
+    ExecutionContext& ctx, ASIO_MOVE_ARG(CompletionToken) token,
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type* = 0);
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/post.hpp"
+
+#endif // ASIO_POST_HPP
diff --git a/subprojects/asio/include/asio/raw_socket_service.hpp b/subprojects/asio/include/asio/raw_socket_service.hpp
new file mode 100644
index 000000000..2bccf032e
--- /dev/null
+++ b/subprojects/asio/include/asio/raw_socket_service.hpp
@@ -0,0 +1,466 @@
+//
+// raw_socket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_RAW_SOCKET_SERVICE_HPP
+#define ASIO_RAW_SOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/null_socket_service.hpp"
+#elif defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_socket_service.hpp"
+#else
+# include "asio/detail/reactive_socket_service.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a raw socket.
+template <typename Protocol>
+class raw_socket_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<raw_socket_service<Protocol> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+private:
+  // The type of the platform-specific implementation.
+#if defined(ASIO_WINDOWS_RUNTIME)
+  typedef detail::null_socket_service<Protocol> service_impl_type;
+#elif defined(ASIO_HAS_IOCP)
+  typedef detail::win_iocp_socket_service<Protocol> service_impl_type;
+#else
+  typedef detail::reactive_socket_service<Protocol> service_impl_type;
+#endif
+
+public:
+  /// The type of a raw socket.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native socket type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new raw socket service for the specified io_context.
+  explicit raw_socket_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        raw_socket_service<Protocol> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new raw socket implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new raw socket implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another raw socket implementation.
+  void move_assign(implementation_type& impl,
+      raw_socket_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+
+  // All socket services have access to each other's implementations.
+  template <typename Protocol1> friend class raw_socket_service;
+
+  /// Move-construct a new raw socket implementation from another protocol
+  /// type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      raw_socket_service<Protocol1>& other_service,
+      typename raw_socket_service<
+        Protocol1>::implementation_type& other_impl,
+      typename enable_if<is_convertible<
+        Protocol1, Protocol>::value>::type* = 0)
+  {
+    service_impl_.template converting_move_construct<Protocol1>(
+        impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a raw socket implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  // Open a new raw socket implementation.
+  ASIO_SYNC_OP_VOID open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    if (protocol.type() == ASIO_OS_DEF(SOCK_RAW))
+      service_impl_.open(impl, protocol, ec);
+    else
+      ec = asio::error::invalid_argument;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native socket to a raw socket.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_socket,
+      asio::error_code& ec)
+  {
+    service_impl_.assign(impl, protocol, native_socket, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a raw socket implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Release ownership of the underlying socket.
+  native_handle_type release(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return service_impl_.release(impl, ec);
+  }
+
+  /// Get the native socket implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the socket.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.at_mark(impl, ec);
+  }
+
+  /// Determine the number of bytes available for reading.
+  std::size_t available(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.available(impl, ec);
+  }
+
+  // Bind the raw socket to the specified local endpoint.
+  ASIO_SYNC_OP_VOID bind(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    service_impl_.bind(impl, endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Connect the raw socket to the specified endpoint.
+  ASIO_SYNC_OP_VOID connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    service_impl_.connect(impl, peer_endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous connect.
+  template <typename ConnectHandler>
+  ASIO_INITFN_RESULT_TYPE(ConnectHandler,
+      void (asio::error_code))
+  async_connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint,
+      ASIO_MOVE_ARG(ConnectHandler) handler)
+  {
+    async_completion<ConnectHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_connect(impl, peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Set a socket option.
+  template <typename SettableSocketOption>
+  ASIO_SYNC_OP_VOID set_option(implementation_type& impl,
+      const SettableSocketOption& option, asio::error_code& ec)
+  {
+    service_impl_.set_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get a socket option.
+  template <typename GettableSocketOption>
+  ASIO_SYNC_OP_VOID get_option(const implementation_type& impl,
+      GettableSocketOption& option, asio::error_code& ec) const
+  {
+    service_impl_.get_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the socket.
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(implementation_type& impl,
+      IoControlCommand& command, asio::error_code& ec)
+  {
+    service_impl_.io_control(impl, command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the socket.
+  bool non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the socket.
+  ASIO_SYNC_OP_VOID non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.native_non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the native socket implementation.
+  ASIO_SYNC_OP_VOID native_non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.native_non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.local_endpoint(impl, ec);
+  }
+
+  /// Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.remote_endpoint(impl, ec);
+  }
+
+  /// Disable sends or receives on the socket.
+  ASIO_SYNC_OP_VOID shutdown(implementation_type& impl,
+      socket_base::shutdown_type what, asio::error_code& ec)
+  {
+    service_impl_.shutdown(impl, what, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the socket to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  ASIO_SYNC_OP_VOID wait(implementation_type& impl,
+      socket_base::wait_type w, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the socket to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl, socket_base::wait_type w,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, w, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Send the given data to the peer.
+  template <typename ConstBufferSequence>
+  std::size_t send(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.send(impl, buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(implementation_type& impl, const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_send(impl, buffers, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Send raw data to the specified endpoint.
+  template <typename ConstBufferSequence>
+  std::size_t send_to(implementation_type& impl,
+      const ConstBufferSequence& buffers, const endpoint_type& destination,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.send_to(impl, buffers, destination, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send_to(implementation_type& impl,
+      const ConstBufferSequence& buffers, const endpoint_type& destination,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_send_to(impl, buffers,
+        destination, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Receive some data from the peer.
+  template <typename MutableBufferSequence>
+  std::size_t receive(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.receive(impl, buffers, flags, ec);
+  }
+
+  /// Start an asynchronous receive.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_receive(impl, buffers, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Receive raw data with the endpoint of the sender.
+  template <typename MutableBufferSequence>
+  std::size_t receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers, endpoint_type& sender_endpoint,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.receive_from(impl, buffers, sender_endpoint, flags,
+        ec);
+  }
+
+  /// Start an asynchronous receive that will get the endpoint of the sender.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive_from(implementation_type& impl,
+      const MutableBufferSequence& buffers, endpoint_type& sender_endpoint,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_receive_from(impl, buffers,
+        sender_endpoint, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_RAW_SOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/read.hpp b/subprojects/asio/include/asio/read.hpp
new file mode 100644
index 000000000..02e8b6778
--- /dev/null
+++ b/subprojects/asio/include/asio/read.hpp
@@ -0,0 +1,947 @@
+//
+// read.hpp
+// ~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_READ_HPP
+#define ASIO_READ_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/buffer.hpp"
+#include "asio/error.hpp"
+
+#if !defined(ASIO_NO_EXTENSIONS)
+# include "asio/basic_streambuf_fwd.hpp"
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/**
+ * @defgroup read asio::read
+ *
+ * @brief The @c read function is a composed operation that reads a certain
+ * amount of data from a stream before returning.
+ */
+/*@{*/
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * stream.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::read(s, asio::buffer(data, size)); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read(
+ *     s, buffers,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncReadStream, typename MutableBufferSequence>
+std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type* = 0);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * stream.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::read(s, asio::buffer(data, size), ec); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read(
+ *     s, buffers,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncReadStream, typename MutableBufferSequence>
+std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type* = 0);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * stream.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's read_some function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::read(s, asio::buffer(data, size),
+ *     asio::transfer_at_least(32)); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename SyncReadStream, typename MutableBufferSequence,
+  typename CompletionCondition>
+std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type* = 0);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * stream.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's read_some function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes read. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncReadStream, typename MutableBufferSequence,
+    typename CompletionCondition>
+std::size_t read(SyncReadStream& s, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type* = 0);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The specified dynamic buffer sequence is full (that is, it has reached
+ * maximum size).
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read(
+ *     s, buffers,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffer is full (that is, it has reached maximum size).
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read(
+ *     s, buffers,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The specified dynamic buffer sequence is full (that is, it has reached
+ * maximum size).
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's read_some function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ */
+template <typename SyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition>
+std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The specified dynamic buffer sequence is full (that is, it has reached
+ * maximum size).
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's read_some function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes read. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition>
+std::size_t read(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffer is full (that is, it has reached maximum size).
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read(
+ *     s, b,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read(SyncReadStream& s, basic_streambuf<Allocator>& b);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffer is full (that is, it has reached maximum size).
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read(
+ *     s, b,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read(SyncReadStream& s, basic_streambuf<Allocator>& b,
+    asio::error_code& ec);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffer is full (that is, it has reached maximum size).
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's read_some function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ */
+template <typename SyncReadStream, typename Allocator,
+    typename CompletionCondition>
+std::size_t read(SyncReadStream& s, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition);
+
+/// Attempt to read a certain amount of data from a stream before returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * stream. The call will block until one of the following conditions is true:
+ *
+ * @li The supplied buffer is full (that is, it has reached maximum size).
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's read_some function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes read. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncReadStream, typename Allocator,
+    typename CompletionCondition>
+std::size_t read(SyncReadStream& s, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, asio::error_code& ec);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+/**
+ * @defgroup async_read asio::async_read
+ *
+ * @brief The @c async_read function is a composed asynchronous operation that
+ * reads a certain amount of data from a stream before completion.
+ */
+/*@{*/
+
+/// Start an asynchronous operation to read a certain amount of data from a
+/// stream.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions is
+ * true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other read operations (such
+ * as async_read, the stream's async_read_some function, or any other composed
+ * operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * stream. Although the buffers object may be copied as necessary, ownership of
+ * the underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes copied into the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be the  number of
+ *                                           // bytes successfully transferred
+ *                                           // prior to the error.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code
+ * asio::async_read(s, asio::buffer(data, size), handler);
+ * @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::async_read(
+ *     s, buffers,
+ *     asio::transfer_all(),
+ *     handler); @endcode
+ */
+template <typename AsyncReadStream, typename MutableBufferSequence,
+    typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, const MutableBufferSequence& buffers,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type* = 0);
+
+/// Start an asynchronous operation to read a certain amount of data from a
+/// stream.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions is
+ * true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * stream. Although the buffers object may be copied as necessary, ownership of
+ * the underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's async_read_some function.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes copied into the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be the  number of
+ *                                           // bytes successfully transferred
+ *                                           // prior to the error.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::async_read(s,
+ *     asio::buffer(data, size),
+ *     asio::transfer_at_least(32),
+ *     handler); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename AsyncReadStream, typename MutableBufferSequence,
+    typename CompletionCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_mutable_buffer_sequence<MutableBufferSequence>::value
+    >::type* = 0);
+
+/// Start an asynchronous operation to read a certain amount of data from a
+/// stream.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions is
+ * true:
+ *
+ * @li The specified dynamic buffer sequence is full (that is, it has reached
+ * maximum size).
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other read operations (such
+ * as async_read, the stream's async_read_some function, or any other composed
+ * operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes copied into the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be the  number of
+ *                                           // bytes successfully transferred
+ *                                           // prior to the error.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::async_read(
+ *     s, buffers,
+ *     asio::transfer_all(),
+ *     handler); @endcode
+ */
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Start an asynchronous operation to read a certain amount of data from a
+/// stream.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions is
+ * true:
+ *
+ * @li The specified dynamic buffer sequence is full (that is, it has reached
+ * maximum size).
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other read operations (such
+ * as async_read, the stream's async_read_some function, or any other composed
+ * operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's async_read_some function.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes copied into the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be the  number of
+ *                                           // bytes successfully transferred
+ *                                           // prior to the error.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename CompletionCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Start an asynchronous operation to read a certain amount of data from a
+/// stream.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions is
+ * true:
+ *
+ * @li The supplied buffer is full (that is, it has reached maximum size).
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other read operations (such
+ * as async_read, the stream's async_read_some function, or any other composed
+ * operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param b A basic_streambuf object into which the data will be read. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes copied into the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be the  number of
+ *                                           // bytes successfully transferred
+ *                                           // prior to the error.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::async_read(
+ *     s, b,
+ *     asio::transfer_all(),
+ *     handler); @endcode
+ */
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, basic_streambuf<Allocator>& b,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+/// Start an asynchronous operation to read a certain amount of data from a
+/// stream.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions is
+ * true:
+ *
+ * @li The supplied buffer is full (that is, it has reached maximum size).
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other read operations (such
+ * as async_read, the stream's async_read_some function, or any other composed
+ * operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param b A basic_streambuf object into which the data will be read. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_read_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the stream's async_read_some function.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes copied into the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be the  number of
+ *                                           // bytes successfully transferred
+ *                                           // prior to the error.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncReadStream, typename Allocator,
+    typename CompletionCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read(AsyncReadStream& s, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/read.hpp"
+
+#endif // ASIO_READ_HPP
diff --git a/subprojects/asio/include/asio/read_at.hpp b/subprojects/asio/include/asio/read_at.hpp
new file mode 100644
index 000000000..3e25a9152
--- /dev/null
+++ b/subprojects/asio/include/asio/read_at.hpp
@@ -0,0 +1,671 @@
+//
+// read_at.hpp
+// ~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_READ_AT_HPP
+#define ASIO_READ_AT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/cstdint.hpp"
+#include "asio/error.hpp"
+
+#if !defined(ASIO_NO_EXTENSIONS)
+# include "asio/basic_streambuf_fwd.hpp"
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/**
+ * @defgroup read_at asio::read_at
+ *
+ * @brief The @c read_at function is a composed operation that reads a certain
+ * amount of data at the specified offset before returning.
+ */
+/*@{*/
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * device.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::read_at(d, 42, asio::buffer(data, size)); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read_at(
+ *     d, 42, buffers,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers);
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * device.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::read_at(d, 42,
+ *     asio::buffer(data, size), ec); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read_at(
+ *     d, 42, buffers,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    asio::error_code& ec);
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * device.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the device's read_some_at function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::read_at(d, 42, asio::buffer(data, size),
+ *     asio::transfer_at_least(32)); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition);
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * device.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the device's read_some_at function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes read. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read_at(
+ *     d, 42, b,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncRandomAccessReadDevice, typename Allocator>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b);
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::read_at(
+ *     d, 42, b,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncRandomAccessReadDevice, typename Allocator>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b,
+    asio::error_code& ec);
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the device's read_some_at function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ */
+template <typename SyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition);
+
+/// Attempt to read a certain amount of data at the specified offset before
+/// returning.
+/**
+ * This function is used to read a certain number of bytes of data from a
+ * random access device at the specified offset. The call will block until one
+ * of the following conditions is true:
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the SyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param b The basic_streambuf object into which the data will be read.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest read_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the device's read_some_at function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes read. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition>
+std::size_t read_at(SyncRandomAccessReadDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, asio::error_code& ec);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+/**
+ * @defgroup async_read_at asio::async_read_at
+ *
+ * @brief The @c async_read_at function is a composed asynchronous operation
+ * that reads a certain amount of data at the specified offset.
+ */
+/*@{*/
+
+/// Start an asynchronous operation to read a certain amount of data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a random access device at the specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * async_read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the AsyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * device. Although the buffers object may be copied as necessary, ownership of
+ * the underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes copied into the buffers. If an error
+ *   // occurred, this will be the number of bytes successfully
+ *   // transferred prior to the error.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code
+ * asio::async_read_at(d, 42, asio::buffer(data, size), handler);
+ * @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::async_read_at(
+ *     d, 42, buffers,
+ *     asio::transfer_all(),
+ *     handler); @endcode
+ */
+template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset,
+    const MutableBufferSequence& buffers,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+/// Start an asynchronous operation to read a certain amount of data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a random access device at the specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li The supplied buffers are full. That is, the bytes transferred is equal to
+ * the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the AsyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param buffers One or more buffers into which the data will be read. The sum
+ * of the buffer sizes indicates the maximum number of bytes to read from the
+ * device. Although the buffers object may be copied as necessary, ownership of
+ * the underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_read_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the device's async_read_some_at function.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes copied into the buffers. If an error
+ *   // occurred, this will be the number of bytes successfully
+ *   // transferred prior to the error.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To read into a single data buffer use the @ref buffer function as follows:
+ * @code asio::async_read_at(d, 42,
+ *     asio::buffer(data, size),
+ *     asio::transfer_at_least(32),
+ *     handler); @endcode
+ * See the @ref buffer documentation for information on reading into multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename AsyncRandomAccessReadDevice, typename MutableBufferSequence,
+    typename CompletionCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, const MutableBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Start an asynchronous operation to read a certain amount of data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a random access device at the specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * async_read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the AsyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param b A basic_streambuf object into which the data will be read. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes copied into the buffers. If an error
+ *   // occurred, this will be the number of bytes successfully
+ *   // transferred prior to the error.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::async_read_at(
+ *     d, 42, b,
+ *     asio::transfer_all(),
+ *     handler); @endcode
+ */
+template <typename AsyncRandomAccessReadDevice, typename Allocator,
+    typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d, uint64_t offset,
+    basic_streambuf<Allocator>& b, ASIO_MOVE_ARG(ReadHandler) handler);
+
+/// Start an asynchronous operation to read a certain amount of data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously read a certain number of bytes of
+ * data from a random access device at the specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * async_read_some_at function.
+ *
+ * @param d The device from which the data is to be read. The type must support
+ * the AsyncRandomAccessReadDevice concept.
+ *
+ * @param offset The offset at which the data will be read.
+ *
+ * @param b A basic_streambuf object into which the data will be read. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the read operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_read_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the read operation is complete. A non-zero
+ * return value indicates the maximum number of bytes to be read on the next
+ * call to the device's async_read_some_at function.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes copied into the buffers. If an error
+ *   // occurred, this will be the number of bytes successfully
+ *   // transferred prior to the error.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncRandomAccessReadDevice, typename Allocator,
+    typename CompletionCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_at(AsyncRandomAccessReadDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/read_at.hpp"
+
+#endif // ASIO_READ_AT_HPP
diff --git a/subprojects/asio/include/asio/read_until.hpp b/subprojects/asio/include/asio/read_until.hpp
new file mode 100644
index 000000000..a346d4ba6
--- /dev/null
+++ b/subprojects/asio/include/asio/read_until.hpp
@@ -0,0 +1,1826 @@
+//
+// read_until.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_READ_UNTIL_HPP
+#define ASIO_READ_UNTIL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <string>
+#include "asio/async_result.hpp"
+#include "asio/detail/regex_fwd.hpp"
+#include "asio/detail/string_view.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+
+#if !defined(ASIO_NO_EXTENSIONS)
+# include "asio/basic_streambuf_fwd.hpp"
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+namespace detail
+{
+  char (&has_result_type_helper(...))[2];
+
+  template <typename T>
+  char has_result_type_helper(T*, typename T::result_type* = 0);
+
+  template <typename T>
+  struct has_result_type
+  {
+    enum { value = (sizeof((has_result_type_helper)((T*)(0))) == 1) };
+  };
+} // namespace detail
+
+/// Type trait used to determine whether a type can be used as a match condition
+/// function with read_until and async_read_until.
+template <typename T>
+struct is_match_condition
+{
+#if defined(GENERATING_DOCUMENTATION)
+  /// The value member is true if the type may be used as a match condition.
+  static const bool value;
+#else
+  enum
+  {
+    value = asio::is_function<
+        typename asio::remove_pointer<T>::type>::value
+      || detail::has_result_type<T>::value
+  };
+#endif
+};
+
+/**
+ * @defgroup read_until asio::read_until
+ *
+ * @brief The @c read_until function is a composed operation that reads data
+ * into a dynamic buffer sequence, or into a streambuf, until it contains a
+ * delimiter, matches a regular expression, or a function object indicates a
+ * match.
+ */
+/*@{*/
+
+/// Read data into a dynamic buffer sequence until it contains a specified
+/// delimiter.
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until the dynamic buffer sequence's get area contains the specified
+ * delimiter. The call will block until one of the following conditions is
+ * true:
+ *
+ * @li The get area of the dynamic buffer sequence contains the specified
+ * delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the dynamic buffer sequence's get area already
+ * contains the delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @param delim The delimiter character.
+ *
+ * @returns The number of bytes in the dynamic buffer sequence's get area up to
+ * and including the delimiter.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond the delimiter. An application will
+ * typically leave that data in the dynamic buffer sequence for a subsequent
+ * read_until operation to examine.
+ *
+ * @par Example
+ * To read data into a @c std::string until a newline is encountered:
+ * @code std::string data;
+ * std::string n = asio::read_until(s,
+ *     asio::dynamic_buffer(data), '\n');
+ * std::string line = data.substr(0, n);
+ * data.erase(0, n); @endcode
+ * After the @c read_until operation completes successfully, the string @c data
+ * contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\n', 'd', 'e', ... } @endcode
+ * The call to @c substr then extracts the data up to and including the
+ * delimiter, so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\n' } @endcode
+ * After the call to @c erase, the remaining data is left in the buffer @c b as
+ * follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c read_until operation.
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers, char delim);
+
+/// Read data into a dynamic buffer sequence until it contains a specified
+/// delimiter.
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until the dynamic buffer sequence's get area contains the specified
+ * delimiter. The call will block until one of the following conditions is
+ * true:
+ *
+ * @li The get area of the dynamic buffer sequence contains the specified
+ * delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the dynamic buffer sequence's get area already
+ * contains the delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @param delim The delimiter character.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the dynamic buffer sequence's get area up to
+ * and including the delimiter. Returns 0 if an error occurred.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond the delimiter. An application will
+ * typically leave that data in the dynamic buffer sequence for a subsequent
+ * read_until operation to examine.
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    char delim, asio::error_code& ec);
+
+/// Read data into a dynamic buffer sequence until it contains a specified
+/// delimiter.
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until the dynamic buffer sequence's get area contains the specified
+ * delimiter. The call will block until one of the following conditions is
+ * true:
+ *
+ * @li The get area of the dynamic buffer sequence contains the specified
+ * delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the dynamic buffer sequence's get area already
+ * contains the delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @param delim The delimiter string.
+ *
+ * @returns The number of bytes in the dynamic buffer sequence's get area up to
+ * and including the delimiter.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond the delimiter. An application will
+ * typically leave that data in the dynamic buffer sequence for a subsequent
+ * read_until operation to examine.
+ *
+ * @par Example
+ * To read data into a @c std::string until a CR-LF sequence is encountered:
+ * @code std::string data;
+ * std::string n = asio::read_until(s,
+ *     asio::dynamic_buffer(data), "\r\n");
+ * std::string line = data.substr(0, n);
+ * data.erase(0, n); @endcode
+ * After the @c read_until operation completes successfully, the string @c data
+ * contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c substr then extracts the data up to and including the
+ * delimiter, so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n' } @endcode
+ * After the call to @c erase, the remaining data is left in the buffer @c b as
+ * follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c read_until operation.
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_STRING_VIEW_PARAM delim);
+
+/// Read data into a dynamic buffer sequence until it contains a specified
+/// delimiter.
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until the dynamic buffer sequence's get area contains the specified
+ * delimiter. The call will block until one of the following conditions is
+ * true:
+ *
+ * @li The get area of the dynamic buffer sequence contains the specified
+ * delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the dynamic buffer sequence's get area already
+ * contains the delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ *
+ * @param delim The delimiter string.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the dynamic buffer sequence's get area up to
+ * and including the delimiter. Returns 0 if an error occurred.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond the delimiter. An application will
+ * typically leave that data in the dynamic buffer sequence for a subsequent
+ * read_until operation to examine.
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_STRING_VIEW_PARAM delim,
+    asio::error_code& ec);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if defined(ASIO_HAS_BOOST_REGEX) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Read data into a dynamic buffer sequence until some part of the data it
+/// contains matches a regular expression.
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until the dynamic buffer sequence's get area contains some data
+ * that matches a regular expression. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li A substring of the dynamic buffer sequence's get area matches the
+ * regular expression.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the dynamic buffer sequence's get area already
+ * contains data that matches the regular expression, the function returns
+ * immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers A dynamic buffer sequence into which the data will be read.
+ *
+ * @param expr The regular expression.
+ *
+ * @returns The number of bytes in the dynamic buffer sequence's get area up to
+ * and including the substring that matches the regular expression.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond that which matched the regular
+ * expression. An application will typically leave that data in the dynamic
+ * buffer sequence for a subsequent read_until operation to examine.
+ *
+ * @par Example
+ * To read data into a @c std::string until a CR-LF sequence is encountered:
+ * @code std::string data;
+ * std::string n = asio::read_until(s,
+ *     asio::dynamic_buffer(data), boost::regex("\r\n"));
+ * std::string line = data.substr(0, n);
+ * data.erase(0, n); @endcode
+ * After the @c read_until operation completes successfully, the string @c data
+ * contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c substr then extracts the data up to and including the
+ * delimiter, so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n' } @endcode
+ * After the call to @c erase, the remaining data is left in the buffer @c b as
+ * follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c read_until operation.
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    const boost::regex& expr);
+
+/// Read data into a dynamic buffer sequence until some part of the data it
+/// contains matches a regular expression.
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until the dynamic buffer sequence's get area contains some data
+ * that matches a regular expression. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li A substring of the dynamic buffer sequence's get area matches the
+ * regular expression.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the dynamic buffer sequence's get area already
+ * contains data that matches the regular expression, the function returns
+ * immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers A dynamic buffer sequence into which the data will be read.
+ *
+ * @param expr The regular expression.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the dynamic buffer sequence's get area up to
+ * and including the substring that matches the regular expression. Returns 0
+ * if an error occurred.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond that which matched the regular
+ * expression. An application will typically leave that data in the dynamic
+ * buffer sequence for a subsequent read_until operation to examine.
+ */
+template <typename SyncReadStream, typename DynamicBuffer>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    const boost::regex& expr, asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+       // || defined(GENERATING_DOCUMENTATION)
+
+/// Read data into a dynamic buffer sequence until a function object indicates a
+/// match.
+
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until a user-defined match condition function object, when applied
+ * to the data contained in the dynamic buffer sequence, indicates a successful
+ * match. The call will block until one of the following conditions is true:
+ *
+ * @li The match condition function object returns a std::pair where the second
+ * element evaluates to true.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the match condition function object already indicates
+ * a match, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers A dynamic buffer sequence into which the data will be read.
+ *
+ * @param match_condition The function object to be called to determine whether
+ * a match exists. The signature of the function object must be:
+ * @code pair<iterator, bool> match_condition(iterator begin, iterator end);
+ * @endcode
+ * where @c iterator represents the type:
+ * @code buffers_iterator<typename DynamicBuffer::const_buffers_type>
+ * @endcode
+ * The iterator parameters @c begin and @c end define the range of bytes to be
+ * scanned to determine whether there is a match. The @c first member of the
+ * return value is an iterator marking one-past-the-end of the bytes that have
+ * been consumed by the match function. This iterator is used to calculate the
+ * @c begin parameter for any subsequent invocation of the match condition. The
+ * @c second member of the return value is true if a match has been found, false
+ * otherwise.
+ *
+ * @returns The number of bytes in the dynamic_buffer's get area that
+ * have been fully consumed by the match function.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond that which matched the function object.
+ * An application will typically leave that data in the dynamic buffer sequence
+ * for a subsequent read_until operation to examine.
+
+ * @note The default implementation of the @c is_match_condition type trait
+ * evaluates to true for function pointers and function objects with a
+ * @c result_type typedef. It must be specialised for other user-defined
+ * function objects.
+ *
+ * @par Examples
+ * To read data into a dynamic buffer sequence until whitespace is encountered:
+ * @code typedef asio::buffers_iterator<
+ *     asio::const_buffers_1> iterator;
+ *
+ * std::pair<iterator, bool>
+ * match_whitespace(iterator begin, iterator end)
+ * {
+ *   iterator i = begin;
+ *   while (i != end)
+ *     if (std::isspace(*i++))
+ *       return std::make_pair(i, true);
+ *   return std::make_pair(i, false);
+ * }
+ * ...
+ * std::string data;
+ * asio::read_until(s, data, match_whitespace);
+ * @endcode
+ *
+ * To read data into a @c std::string until a matching character is found:
+ * @code class match_char
+ * {
+ * public:
+ *   explicit match_char(char c) : c_(c) {}
+ *
+ *   template <typename Iterator>
+ *   std::pair<Iterator, bool> operator()(
+ *       Iterator begin, Iterator end) const
+ *   {
+ *     Iterator i = begin;
+ *     while (i != end)
+ *       if (c_ == *i++)
+ *         return std::make_pair(i, true);
+ *     return std::make_pair(i, false);
+ *   }
+ *
+ * private:
+ *   char c_;
+ * };
+ *
+ * namespace asio {
+ *   template <> struct is_match_condition<match_char>
+ *     : public boost::true_type {};
+ * } // namespace asio
+ * ...
+ * std::string data;
+ * asio::read_until(s, data, match_char('a'));
+ * @endcode
+ */
+template <typename SyncReadStream,
+    typename DynamicBuffer, typename MatchCondition>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    MatchCondition match_condition,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type* = 0);
+
+/// Read data into a dynamic buffer sequence until a function object indicates a
+/// match.
+/**
+ * This function is used to read data into the specified dynamic buffer
+ * sequence until a user-defined match condition function object, when applied
+ * to the data contained in the dynamic buffer sequence, indicates a successful
+ * match. The call will block until one of the following conditions is true:
+ *
+ * @li The match condition function object returns a std::pair where the second
+ * element evaluates to true.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the match condition function object already indicates
+ * a match, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param buffers A dynamic buffer sequence into which the data will be read.
+ *
+ * @param match_condition The function object to be called to determine whether
+ * a match exists. The signature of the function object must be:
+ * @code pair<iterator, bool> match_condition(iterator begin, iterator end);
+ * @endcode
+ * where @c iterator represents the type:
+ * @code buffers_iterator<DynamicBuffer::const_buffers_type>
+ * @endcode
+ * The iterator parameters @c begin and @c end define the range of bytes to be
+ * scanned to determine whether there is a match. The @c first member of the
+ * return value is an iterator marking one-past-the-end of the bytes that have
+ * been consumed by the match function. This iterator is used to calculate the
+ * @c begin parameter for any subsequent invocation of the match condition. The
+ * @c second member of the return value is true if a match has been found, false
+ * otherwise.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the dynamic buffer sequence's get area that
+ * have been fully consumed by the match function. Returns 0 if an error
+ * occurred.
+ *
+ * @note After a successful read_until operation, the dynamic buffer sequence
+ * may contain additional data beyond that which matched the function object.
+ * An application will typically leave that data in the dynamic buffer sequence
+ * for a subsequent read_until operation to examine.
+ *
+ * @note The default implementation of the @c is_match_condition type trait
+ * evaluates to true for function pointers and function objects with a
+ * @c result_type typedef. It must be specialised for other user-defined
+ * function objects.
+ */
+template <typename SyncReadStream,
+    typename DynamicBuffer, typename MatchCondition>
+std::size_t read_until(SyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    MatchCondition match_condition, asio::error_code& ec,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type* = 0);
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Read data into a streambuf until it contains a specified delimiter.
+/**
+ * This function is used to read data into the specified streambuf until the
+ * streambuf's get area contains the specified delimiter. The call will block
+ * until one of the following conditions is true:
+ *
+ * @li The get area of the streambuf contains the specified delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the streambuf's get area already contains the
+ * delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param delim The delimiter character.
+ *
+ * @returns The number of bytes in the streambuf's get area up to and including
+ * the delimiter.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond the delimiter. An application will typically leave
+ * that data in the streambuf for a subsequent read_until operation to examine.
+ *
+ * @par Example
+ * To read data into a streambuf until a newline is encountered:
+ * @code asio::streambuf b;
+ * asio::read_until(s, b, '\n');
+ * std::istream is(&b);
+ * std::string line;
+ * std::getline(is, line); @endcode
+ * After the @c read_until operation completes successfully, the buffer @c b
+ * contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\n', 'd', 'e', ... } @endcode
+ * The call to @c std::getline then extracts the data up to and including the
+ * newline (which is discarded), so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c' } @endcode
+ * The remaining data is left in the buffer @c b as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c read_until operation.
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, char delim);
+
+/// Read data into a streambuf until it contains a specified delimiter.
+/**
+ * This function is used to read data into the specified streambuf until the
+ * streambuf's get area contains the specified delimiter. The call will block
+ * until one of the following conditions is true:
+ *
+ * @li The get area of the streambuf contains the specified delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the streambuf's get area already contains the
+ * delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param delim The delimiter character.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the streambuf's get area up to and including
+ * the delimiter. Returns 0 if an error occurred.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond the delimiter. An application will typically leave
+ * that data in the streambuf for a subsequent read_until operation to examine.
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, char delim,
+    asio::error_code& ec);
+
+/// Read data into a streambuf until it contains a specified delimiter.
+/**
+ * This function is used to read data into the specified streambuf until the
+ * streambuf's get area contains the specified delimiter. The call will block
+ * until one of the following conditions is true:
+ *
+ * @li The get area of the streambuf contains the specified delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the streambuf's get area already contains the
+ * delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param delim The delimiter string.
+ *
+ * @returns The number of bytes in the streambuf's get area up to and including
+ * the delimiter.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond the delimiter. An application will typically leave
+ * that data in the streambuf for a subsequent read_until operation to examine.
+ *
+ * @par Example
+ * To read data into a streambuf until a newline is encountered:
+ * @code asio::streambuf b;
+ * asio::read_until(s, b, "\r\n");
+ * std::istream is(&b);
+ * std::string line;
+ * std::getline(is, line); @endcode
+ * After the @c read_until operation completes successfully, the buffer @c b
+ * contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c std::getline then extracts the data up to and including the
+ * newline (which is discarded), so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r' } @endcode
+ * The remaining data is left in the buffer @c b as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c read_until operation.
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    ASIO_STRING_VIEW_PARAM delim);
+
+/// Read data into a streambuf until it contains a specified delimiter.
+/**
+ * This function is used to read data into the specified streambuf until the
+ * streambuf's get area contains the specified delimiter. The call will block
+ * until one of the following conditions is true:
+ *
+ * @li The get area of the streambuf contains the specified delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the streambuf's get area already contains the
+ * delimiter, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param delim The delimiter string.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the streambuf's get area up to and including
+ * the delimiter. Returns 0 if an error occurred.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond the delimiter. An application will typically leave
+ * that data in the streambuf for a subsequent read_until operation to examine.
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    ASIO_STRING_VIEW_PARAM delim, asio::error_code& ec);
+
+#if defined(ASIO_HAS_BOOST_REGEX) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Read data into a streambuf until some part of the data it contains matches
+/// a regular expression.
+/**
+ * This function is used to read data into the specified streambuf until the
+ * streambuf's get area contains some data that matches a regular expression.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li A substring of the streambuf's get area matches the regular expression.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the streambuf's get area already contains data that
+ * matches the regular expression, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param expr The regular expression.
+ *
+ * @returns The number of bytes in the streambuf's get area up to and including
+ * the substring that matches the regular expression.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond that which matched the regular expression. An
+ * application will typically leave that data in the streambuf for a subsequent
+ * read_until operation to examine.
+ *
+ * @par Example
+ * To read data into a streambuf until a CR-LF sequence is encountered:
+ * @code asio::streambuf b;
+ * asio::read_until(s, b, boost::regex("\r\n"));
+ * std::istream is(&b);
+ * std::string line;
+ * std::getline(is, line); @endcode
+ * After the @c read_until operation completes successfully, the buffer @c b
+ * contains the data which matched the regular expression:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c std::getline then extracts the data up to and including the
+ * newline (which is discarded), so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r' } @endcode
+ * The remaining data is left in the buffer @c b as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c read_until operation.
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, const boost::regex& expr);
+
+/// Read data into a streambuf until some part of the data it contains matches
+/// a regular expression.
+/**
+ * This function is used to read data into the specified streambuf until the
+ * streambuf's get area contains some data that matches a regular expression.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li A substring of the streambuf's get area matches the regular expression.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the streambuf's get area already contains data that
+ * matches the regular expression, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param expr The regular expression.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the streambuf's get area up to and including
+ * the substring that matches the regular expression. Returns 0 if an error
+ * occurred.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond that which matched the regular expression. An
+ * application will typically leave that data in the streambuf for a subsequent
+ * read_until operation to examine.
+ */
+template <typename SyncReadStream, typename Allocator>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, const boost::regex& expr,
+    asio::error_code& ec);
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+       // || defined(GENERATING_DOCUMENTATION)
+
+/// Read data into a streambuf until a function object indicates a match.
+/**
+ * This function is used to read data into the specified streambuf until a
+ * user-defined match condition function object, when applied to the data
+ * contained in the streambuf, indicates a successful match. The call will
+ * block until one of the following conditions is true:
+ *
+ * @li The match condition function object returns a std::pair where the second
+ * element evaluates to true.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the match condition function object already indicates
+ * a match, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param match_condition The function object to be called to determine whether
+ * a match exists. The signature of the function object must be:
+ * @code pair<iterator, bool> match_condition(iterator begin, iterator end);
+ * @endcode
+ * where @c iterator represents the type:
+ * @code buffers_iterator<basic_streambuf<Allocator>::const_buffers_type>
+ * @endcode
+ * The iterator parameters @c begin and @c end define the range of bytes to be
+ * scanned to determine whether there is a match. The @c first member of the
+ * return value is an iterator marking one-past-the-end of the bytes that have
+ * been consumed by the match function. This iterator is used to calculate the
+ * @c begin parameter for any subsequent invocation of the match condition. The
+ * @c second member of the return value is true if a match has been found, false
+ * otherwise.
+ *
+ * @returns The number of bytes in the streambuf's get area that have been fully
+ * consumed by the match function.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond that which matched the function object. An application
+ * will typically leave that data in the streambuf for a subsequent read_until
+ * operation to examine.
+ *
+ * @note The default implementation of the @c is_match_condition type trait
+ * evaluates to true for function pointers and function objects with a
+ * @c result_type typedef. It must be specialised for other user-defined
+ * function objects.
+ *
+ * @par Examples
+ * To read data into a streambuf until whitespace is encountered:
+ * @code typedef asio::buffers_iterator<
+ *     asio::streambuf::const_buffers_type> iterator;
+ *
+ * std::pair<iterator, bool>
+ * match_whitespace(iterator begin, iterator end)
+ * {
+ *   iterator i = begin;
+ *   while (i != end)
+ *     if (std::isspace(*i++))
+ *       return std::make_pair(i, true);
+ *   return std::make_pair(i, false);
+ * }
+ * ...
+ * asio::streambuf b;
+ * asio::read_until(s, b, match_whitespace);
+ * @endcode
+ *
+ * To read data into a streambuf until a matching character is found:
+ * @code class match_char
+ * {
+ * public:
+ *   explicit match_char(char c) : c_(c) {}
+ *
+ *   template <typename Iterator>
+ *   std::pair<Iterator, bool> operator()(
+ *       Iterator begin, Iterator end) const
+ *   {
+ *     Iterator i = begin;
+ *     while (i != end)
+ *       if (c_ == *i++)
+ *         return std::make_pair(i, true);
+ *     return std::make_pair(i, false);
+ *   }
+ *
+ * private:
+ *   char c_;
+ * };
+ *
+ * namespace asio {
+ *   template <> struct is_match_condition<match_char>
+ *     : public boost::true_type {};
+ * } // namespace asio
+ * ...
+ * asio::streambuf b;
+ * asio::read_until(s, b, match_char('a'));
+ * @endcode
+ */
+template <typename SyncReadStream, typename Allocator, typename MatchCondition>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, MatchCondition match_condition,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type* = 0);
+
+/// Read data into a streambuf until a function object indicates a match.
+/**
+ * This function is used to read data into the specified streambuf until a
+ * user-defined match condition function object, when applied to the data
+ * contained in the streambuf, indicates a successful match. The call will
+ * block until one of the following conditions is true:
+ *
+ * @li The match condition function object returns a std::pair where the second
+ * element evaluates to true.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * read_some function. If the match condition function object already indicates
+ * a match, the function returns immediately.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the SyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param match_condition The function object to be called to determine whether
+ * a match exists. The signature of the function object must be:
+ * @code pair<iterator, bool> match_condition(iterator begin, iterator end);
+ * @endcode
+ * where @c iterator represents the type:
+ * @code buffers_iterator<basic_streambuf<Allocator>::const_buffers_type>
+ * @endcode
+ * The iterator parameters @c begin and @c end define the range of bytes to be
+ * scanned to determine whether there is a match. The @c first member of the
+ * return value is an iterator marking one-past-the-end of the bytes that have
+ * been consumed by the match function. This iterator is used to calculate the
+ * @c begin parameter for any subsequent invocation of the match condition. The
+ * @c second member of the return value is true if a match has been found, false
+ * otherwise.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes in the streambuf's get area that have been fully
+ * consumed by the match function. Returns 0 if an error occurred.
+ *
+ * @note After a successful read_until operation, the streambuf may contain
+ * additional data beyond that which matched the function object. An application
+ * will typically leave that data in the streambuf for a subsequent read_until
+ * operation to examine.
+ *
+ * @note The default implementation of the @c is_match_condition type trait
+ * evaluates to true for function pointers and function objects with a
+ * @c result_type typedef. It must be specialised for other user-defined
+ * function objects.
+ */
+template <typename SyncReadStream, typename Allocator, typename MatchCondition>
+std::size_t read_until(SyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    MatchCondition match_condition, asio::error_code& ec,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type* = 0);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+/**
+ * @defgroup async_read_until asio::async_read_until
+ *
+ * @brief The @c async_read_until function is a composed asynchronous operation
+ * that reads data into a dynamic buffer sequence, or into a streambuf, until
+ * it contains a delimiter, matches a regular expression, or a function object
+ * indicates a match.
+ */
+/*@{*/
+
+/// Start an asynchronous operation to read data into a dynamic buffer sequence
+/// until it contains a specified delimiter.
+/**
+ * This function is used to asynchronously read data into the specified dynamic
+ * buffer sequence until the dynamic buffer sequence's get area contains the
+ * specified delimiter. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li The get area of the dynamic buffer sequence contains the specified
+ * delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the dynamic buffer sequence's get area already contains the delimiter, this
+ * asynchronous operation completes immediately. The program must ensure that
+ * the stream performs no other read operations (such as async_read,
+ * async_read_until, the stream's async_read_some function, or any other
+ * composed operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param delim The delimiter character.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the dynamic buffer sequence's
+ *   // get area up to and including the delimiter.
+ *   // 0 if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the dynamic buffer
+ * sequence may contain additional data beyond the delimiter. An application
+ * will typically leave that data in the dynamic buffer sequence for a
+ * subsequent async_read_until operation to examine.
+ *
+ * @par Example
+ * To asynchronously read data into a @c std::string until a newline is
+ * encountered:
+ * @code std::string data;
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size)
+ * {
+ *   if (!e)
+ *   {
+ *     std::string line = data.substr(0, n);
+ *     data.erase(0, n);
+ *     ...
+ *   }
+ * }
+ * ...
+ * asio::async_read_until(s, data, '\n', handler); @endcode
+ * After the @c async_read_until operation completes successfully, the buffer
+ * @c data contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\n', 'd', 'e', ... } @endcode
+ * The call to @c substr then extracts the data up to and including the
+ * delimiter, so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\n' } @endcode
+ * After the call to @c erase, the remaining data is left in the buffer @c data
+ * as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c async_read_until operation.
+ */
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    char delim, ASIO_MOVE_ARG(ReadHandler) handler);
+
+/// Start an asynchronous operation to read data into a dynamic buffer sequence
+/// until it contains a specified delimiter.
+/**
+ * This function is used to asynchronously read data into the specified dynamic
+ * buffer sequence until the dynamic buffer sequence's get area contains the
+ * specified delimiter. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li The get area of the dynamic buffer sequence contains the specified
+ * delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the dynamic buffer sequence's get area already contains the delimiter, this
+ * asynchronous operation completes immediately. The program must ensure that
+ * the stream performs no other read operations (such as async_read,
+ * async_read_until, the stream's async_read_some function, or any other
+ * composed operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param delim The delimiter string.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the dynamic buffer sequence's
+ *   // get area up to and including the delimiter.
+ *   // 0 if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the dynamic buffer
+ * sequence may contain additional data beyond the delimiter. An application
+ * will typically leave that data in the dynamic buffer sequence for a
+ * subsequent async_read_until operation to examine.
+ *
+ * @par Example
+ * To asynchronously read data into a @c std::string until a CR-LF sequence is
+ * encountered:
+ * @code std::string data;
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size)
+ * {
+ *   if (!e)
+ *   {
+ *     std::string line = data.substr(0, n);
+ *     data.erase(0, n);
+ *     ...
+ *   }
+ * }
+ * ...
+ * asio::async_read_until(s, data, "\r\n", handler); @endcode
+ * After the @c async_read_until operation completes successfully, the string
+ * @c data contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c substr then extracts the data up to and including the
+ * delimiter, so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n' } @endcode
+ * After the call to @c erase, the remaining data is left in the string @c data
+ * as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c async_read_until operation.
+ */
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_STRING_VIEW_PARAM delim,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if defined(ASIO_HAS_BOOST_REGEX) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Start an asynchronous operation to read data into a dynamic buffer sequence
+/// until some part of its data matches a regular expression.
+/**
+ * This function is used to asynchronously read data into the specified dynamic
+ * buffer sequence until the dynamic buffer sequence's get area contains some
+ * data that matches a regular expression. The function call always returns
+ * immediately. The asynchronous operation will continue until one of the
+ * following conditions is true:
+ *
+ * @li A substring of the dynamic buffer sequence's get area matches the regular
+ * expression.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the dynamic buffer sequence's get area already contains data that matches
+ * the regular expression, this asynchronous operation completes immediately.
+ * The program must ensure that the stream performs no other read operations
+ * (such as async_read, async_read_until, the stream's async_read_some
+ * function, or any other composed operations that perform reads) until this
+ * operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param expr The regular expression.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the dynamic buffer
+ *   // sequence's get area up to and including the
+ *   // substring that matches the regular expression.
+ *   // 0 if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the dynamic buffer
+ * sequence may contain additional data beyond that which matched the regular
+ * expression. An application will typically leave that data in the dynamic
+ * buffer sequence for a subsequent async_read_until operation to examine.
+ *
+ * @par Example
+ * To asynchronously read data into a @c std::string until a CR-LF sequence is
+ * encountered:
+ * @code std::string data;
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size)
+ * {
+ *   if (!e)
+ *   {
+ *     std::string line = data.substr(0, n);
+ *     data.erase(0, n);
+ *     ...
+ *   }
+ * }
+ * ...
+ * asio::async_read_until(s, data,
+ *     boost::regex("\r\n"), handler); @endcode
+ * After the @c async_read_until operation completes successfully, the string
+ * @c data contains the data which matched the regular expression:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c substr then extracts the data up to and including the match,
+ * so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n' } @endcode
+ * After the call to @c erase, the remaining data is left in the string @c data
+ * as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c async_read_until operation.
+ */
+template <typename AsyncReadStream,
+    typename DynamicBuffer, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    const boost::regex& expr,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+       // || defined(GENERATING_DOCUMENTATION)
+
+/// Start an asynchronous operation to read data into a dynamic buffer sequence
+/// until a function object indicates a match.
+/**
+ * This function is used to asynchronously read data into the specified dynamic
+ * buffer sequence until a user-defined match condition function object, when
+ * applied to the data contained in the dynamic buffer sequence, indicates a
+ * successful match. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li The match condition function object returns a std::pair where the second
+ * element evaluates to true.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the match condition function object already indicates a match, this
+ * asynchronous operation completes immediately. The program must ensure that
+ * the stream performs no other read operations (such as async_read,
+ * async_read_until, the stream's async_read_some function, or any other
+ * composed operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param buffers The dynamic buffer sequence into which the data will be read.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param match_condition The function object to be called to determine whether
+ * a match exists. The signature of the function object must be:
+ * @code pair<iterator, bool> match_condition(iterator begin, iterator end);
+ * @endcode
+ * where @c iterator represents the type:
+ * @code buffers_iterator<typename DynamicBuffer::const_buffers_type>
+ * @endcode
+ * The iterator parameters @c begin and @c end define the range of bytes to be
+ * scanned to determine whether there is a match. The @c first member of the
+ * return value is an iterator marking one-past-the-end of the bytes that have
+ * been consumed by the match function. This iterator is used to calculate the
+ * @c begin parameter for any subsequent invocation of the match condition. The
+ * @c second member of the return value is true if a match has been found, false
+ * otherwise.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the dynamic buffer sequence's
+ *   // get area that have been fully consumed by the match
+ *   // function. O if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the dynamic buffer
+ * sequence may contain additional data beyond that which matched the function
+ * object. An application will typically leave that data in the dynamic buffer
+ * sequence for a subsequent async_read_until operation to examine.
+ *
+ * @note The default implementation of the @c is_match_condition type trait
+ * evaluates to true for function pointers and function objects with a
+ * @c result_type typedef. It must be specialised for other user-defined
+ * function objects.
+ *
+ * @par Examples
+ * To asynchronously read data into a @c std::string until whitespace is
+ * encountered:
+ * @code typedef asio::buffers_iterator<
+ *     asio::const_buffers_1> iterator;
+ *
+ * std::pair<iterator, bool>
+ * match_whitespace(iterator begin, iterator end)
+ * {
+ *   iterator i = begin;
+ *   while (i != end)
+ *     if (std::isspace(*i++))
+ *       return std::make_pair(i, true);
+ *   return std::make_pair(i, false);
+ * }
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size);
+ * ...
+ * std::string data;
+ * asio::async_read_until(s, data, match_whitespace, handler);
+ * @endcode
+ *
+ * To asynchronously read data into a @c std::string until a matching character
+ * is found:
+ * @code class match_char
+ * {
+ * public:
+ *   explicit match_char(char c) : c_(c) {}
+ *
+ *   template <typename Iterator>
+ *   std::pair<Iterator, bool> operator()(
+ *       Iterator begin, Iterator end) const
+ *   {
+ *     Iterator i = begin;
+ *     while (i != end)
+ *       if (c_ == *i++)
+ *         return std::make_pair(i, true);
+ *     return std::make_pair(i, false);
+ *   }
+ *
+ * private:
+ *   char c_;
+ * };
+ *
+ * namespace asio {
+ *   template <> struct is_match_condition<match_char>
+ *     : public boost::true_type {};
+ * } // namespace asio
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size);
+ * ...
+ * std::string data;
+ * asio::async_read_until(s, data, match_char('a'), handler);
+ * @endcode
+ */
+template <typename AsyncReadStream, typename DynamicBuffer,
+    typename MatchCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    MatchCondition match_condition, ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type* = 0);
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Start an asynchronous operation to read data into a streambuf until it
+/// contains a specified delimiter.
+/**
+ * This function is used to asynchronously read data into the specified
+ * streambuf until the streambuf's get area contains the specified delimiter.
+ * The function call always returns immediately. The asynchronous operation
+ * will continue until one of the following conditions is true:
+ *
+ * @li The get area of the streambuf contains the specified delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the streambuf's get area already contains the delimiter, this asynchronous
+ * operation completes immediately. The program must ensure that the stream
+ * performs no other read operations (such as async_read, async_read_until, the
+ * stream's async_read_some function, or any other composed operations that
+ * perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read. Ownership of
+ * the streambuf is retained by the caller, which must guarantee that it remains
+ * valid until the handler is called.
+ *
+ * @param delim The delimiter character.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the streambuf's get
+ *   // area up to and including the delimiter.
+ *   // 0 if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the streambuf may
+ * contain additional data beyond the delimiter. An application will typically
+ * leave that data in the streambuf for a subsequent async_read_until operation
+ * to examine.
+ *
+ * @par Example
+ * To asynchronously read data into a streambuf until a newline is encountered:
+ * @code asio::streambuf b;
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size)
+ * {
+ *   if (!e)
+ *   {
+ *     std::istream is(&b);
+ *     std::string line;
+ *     std::getline(is, line);
+ *     ...
+ *   }
+ * }
+ * ...
+ * asio::async_read_until(s, b, '\n', handler); @endcode
+ * After the @c async_read_until operation completes successfully, the buffer
+ * @c b contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\n', 'd', 'e', ... } @endcode
+ * The call to @c std::getline then extracts the data up to and including the
+ * newline (which is discarded), so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c' } @endcode
+ * The remaining data is left in the buffer @c b as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c async_read_until operation.
+ */
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    char delim, ASIO_MOVE_ARG(ReadHandler) handler);
+
+/// Start an asynchronous operation to read data into a streambuf until it
+/// contains a specified delimiter.
+/**
+ * This function is used to asynchronously read data into the specified
+ * streambuf until the streambuf's get area contains the specified delimiter.
+ * The function call always returns immediately. The asynchronous operation
+ * will continue until one of the following conditions is true:
+ *
+ * @li The get area of the streambuf contains the specified delimiter.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the streambuf's get area already contains the delimiter, this asynchronous
+ * operation completes immediately. The program must ensure that the stream
+ * performs no other read operations (such as async_read, async_read_until, the
+ * stream's async_read_some function, or any other composed operations that
+ * perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read. Ownership of
+ * the streambuf is retained by the caller, which must guarantee that it remains
+ * valid until the handler is called.
+ *
+ * @param delim The delimiter string.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the streambuf's get
+ *   // area up to and including the delimiter.
+ *   // 0 if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the streambuf may
+ * contain additional data beyond the delimiter. An application will typically
+ * leave that data in the streambuf for a subsequent async_read_until operation
+ * to examine.
+ *
+ * @par Example
+ * To asynchronously read data into a streambuf until a newline is encountered:
+ * @code asio::streambuf b;
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size)
+ * {
+ *   if (!e)
+ *   {
+ *     std::istream is(&b);
+ *     std::string line;
+ *     std::getline(is, line);
+ *     ...
+ *   }
+ * }
+ * ...
+ * asio::async_read_until(s, b, "\r\n", handler); @endcode
+ * After the @c async_read_until operation completes successfully, the buffer
+ * @c b contains the delimiter:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c std::getline then extracts the data up to and including the
+ * newline (which is discarded), so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r' } @endcode
+ * The remaining data is left in the buffer @c b as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c async_read_until operation.
+ */
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    ASIO_STRING_VIEW_PARAM delim,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+#if defined(ASIO_HAS_BOOST_REGEX) \
+  || defined(GENERATING_DOCUMENTATION)
+
+/// Start an asynchronous operation to read data into a streambuf until some
+/// part of its data matches a regular expression.
+/**
+ * This function is used to asynchronously read data into the specified
+ * streambuf until the streambuf's get area contains some data that matches a
+ * regular expression. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li A substring of the streambuf's get area matches the regular expression.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the streambuf's get area already contains data that matches the regular
+ * expression, this asynchronous operation completes immediately. The program
+ * must ensure that the stream performs no other read operations (such as
+ * async_read, async_read_until, the stream's async_read_some function, or any
+ * other composed operations that perform reads) until this operation
+ * completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read. Ownership of
+ * the streambuf is retained by the caller, which must guarantee that it remains
+ * valid until the handler is called.
+ *
+ * @param expr The regular expression.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the streambuf's get
+ *   // area up to and including the substring
+ *   // that matches the regular. expression.
+ *   // 0 if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the streambuf may
+ * contain additional data beyond that which matched the regular expression. An
+ * application will typically leave that data in the streambuf for a subsequent
+ * async_read_until operation to examine.
+ *
+ * @par Example
+ * To asynchronously read data into a streambuf until a CR-LF sequence is
+ * encountered:
+ * @code asio::streambuf b;
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size)
+ * {
+ *   if (!e)
+ *   {
+ *     std::istream is(&b);
+ *     std::string line;
+ *     std::getline(is, line);
+ *     ...
+ *   }
+ * }
+ * ...
+ * asio::async_read_until(s, b, boost::regex("\r\n"), handler); @endcode
+ * After the @c async_read_until operation completes successfully, the buffer
+ * @c b contains the data which matched the regular expression:
+ * @code { 'a', 'b', ..., 'c', '\r', '\n', 'd', 'e', ... } @endcode
+ * The call to @c std::getline then extracts the data up to and including the
+ * newline (which is discarded), so that the string @c line contains:
+ * @code { 'a', 'b', ..., 'c', '\r' } @endcode
+ * The remaining data is left in the buffer @c b as follows:
+ * @code { 'd', 'e', ... } @endcode
+ * This data may be the start of a new line, to be extracted by a subsequent
+ * @c async_read_until operation.
+ */
+template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b, const boost::regex& expr,
+    ASIO_MOVE_ARG(ReadHandler) handler);
+
+#endif // defined(ASIO_HAS_BOOST_REGEX)
+       // || defined(GENERATING_DOCUMENTATION)
+
+/// Start an asynchronous operation to read data into a streambuf until a
+/// function object indicates a match.
+/**
+ * This function is used to asynchronously read data into the specified
+ * streambuf until a user-defined match condition function object, when applied
+ * to the data contained in the streambuf, indicates a successful match. The
+ * function call always returns immediately. The asynchronous operation will
+ * continue until one of the following conditions is true:
+ *
+ * @li The match condition function object returns a std::pair where the second
+ * element evaluates to true.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_read_some function, and is known as a <em>composed operation</em>. If
+ * the match condition function object already indicates a match, this
+ * asynchronous operation completes immediately. The program must ensure that
+ * the stream performs no other read operations (such as async_read,
+ * async_read_until, the stream's async_read_some function, or any other
+ * composed operations that perform reads) until this operation completes.
+ *
+ * @param s The stream from which the data is to be read. The type must support
+ * the AsyncReadStream concept.
+ *
+ * @param b A streambuf object into which the data will be read.
+ *
+ * @param match_condition The function object to be called to determine whether
+ * a match exists. The signature of the function object must be:
+ * @code pair<iterator, bool> match_condition(iterator begin, iterator end);
+ * @endcode
+ * where @c iterator represents the type:
+ * @code buffers_iterator<basic_streambuf<Allocator>::const_buffers_type>
+ * @endcode
+ * The iterator parameters @c begin and @c end define the range of bytes to be
+ * scanned to determine whether there is a match. The @c first member of the
+ * return value is an iterator marking one-past-the-end of the bytes that have
+ * been consumed by the match function. This iterator is used to calculate the
+ * @c begin parameter for any subsequent invocation of the match condition. The
+ * @c second member of the return value is true if a match has been found, false
+ * otherwise.
+ *
+ * @param handler The handler to be called when the read operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // The number of bytes in the streambuf's get
+ *   // area that have been fully consumed by the
+ *   // match function. O if an error occurred.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @note After a successful async_read_until operation, the streambuf may
+ * contain additional data beyond that which matched the function object. An
+ * application will typically leave that data in the streambuf for a subsequent
+ * async_read_until operation to examine.
+ *
+ * @note The default implementation of the @c is_match_condition type trait
+ * evaluates to true for function pointers and function objects with a
+ * @c result_type typedef. It must be specialised for other user-defined
+ * function objects.
+ *
+ * @par Examples
+ * To asynchronously read data into a streambuf until whitespace is encountered:
+ * @code typedef asio::buffers_iterator<
+ *     asio::streambuf::const_buffers_type> iterator;
+ *
+ * std::pair<iterator, bool>
+ * match_whitespace(iterator begin, iterator end)
+ * {
+ *   iterator i = begin;
+ *   while (i != end)
+ *     if (std::isspace(*i++))
+ *       return std::make_pair(i, true);
+ *   return std::make_pair(i, false);
+ * }
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size);
+ * ...
+ * asio::streambuf b;
+ * asio::async_read_until(s, b, match_whitespace, handler);
+ * @endcode
+ *
+ * To asynchronously read data into a streambuf until a matching character is
+ * found:
+ * @code class match_char
+ * {
+ * public:
+ *   explicit match_char(char c) : c_(c) {}
+ *
+ *   template <typename Iterator>
+ *   std::pair<Iterator, bool> operator()(
+ *       Iterator begin, Iterator end) const
+ *   {
+ *     Iterator i = begin;
+ *     while (i != end)
+ *       if (c_ == *i++)
+ *         return std::make_pair(i, true);
+ *     return std::make_pair(i, false);
+ *   }
+ *
+ * private:
+ *   char c_;
+ * };
+ *
+ * namespace asio {
+ *   template <> struct is_match_condition<match_char>
+ *     : public boost::true_type {};
+ * } // namespace asio
+ * ...
+ * void handler(const asio::error_code& e, std::size_t size);
+ * ...
+ * asio::streambuf b;
+ * asio::async_read_until(s, b, match_char('a'), handler);
+ * @endcode
+ */
+template <typename AsyncReadStream, typename Allocator,
+    typename MatchCondition, typename ReadHandler>
+ASIO_INITFN_RESULT_TYPE(ReadHandler,
+    void (asio::error_code, std::size_t))
+async_read_until(AsyncReadStream& s,
+    asio::basic_streambuf<Allocator>& b,
+    MatchCondition match_condition, ASIO_MOVE_ARG(ReadHandler) handler,
+    typename enable_if<is_match_condition<MatchCondition>::value>::type* = 0);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/read_until.hpp"
+
+#endif // ASIO_READ_UNTIL_HPP
diff --git a/subprojects/asio/include/asio/seq_packet_socket_service.hpp b/subprojects/asio/include/asio/seq_packet_socket_service.hpp
new file mode 100644
index 000000000..7e6824d41
--- /dev/null
+++ b/subprojects/asio/include/asio/seq_packet_socket_service.hpp
@@ -0,0 +1,416 @@
+//
+// seq_packet_socket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SEQ_PACKET_SOCKET_SERVICE_HPP
+#define ASIO_SEQ_PACKET_SOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/null_socket_service.hpp"
+#elif defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_socket_service.hpp"
+#else
+# include "asio/detail/reactive_socket_service.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a sequenced packet socket.
+template <typename Protocol>
+class seq_packet_socket_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<
+      seq_packet_socket_service<Protocol> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+private:
+  // The type of the platform-specific implementation.
+#if defined(ASIO_WINDOWS_RUNTIME)
+  typedef detail::null_socket_service<Protocol> service_impl_type;
+#elif defined(ASIO_HAS_IOCP)
+  typedef detail::win_iocp_socket_service<Protocol> service_impl_type;
+#else
+  typedef detail::reactive_socket_service<Protocol> service_impl_type;
+#endif
+
+public:
+  /// The type of a sequenced packet socket implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native socket type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new sequenced packet socket service for the specified
+  /// io_context.
+  explicit seq_packet_socket_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        seq_packet_socket_service<Protocol> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new sequenced packet socket implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new sequenced packet socket implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another sequenced packet socket implementation.
+  void move_assign(implementation_type& impl,
+      seq_packet_socket_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+
+  // All socket services have access to each other's implementations.
+  template <typename Protocol1> friend class seq_packet_socket_service;
+
+  /// Move-construct a new sequenced packet socket implementation from another
+  /// protocol type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      seq_packet_socket_service<Protocol1>& other_service,
+      typename seq_packet_socket_service<
+        Protocol1>::implementation_type& other_impl,
+      typename enable_if<is_convertible<
+        Protocol1, Protocol>::value>::type* = 0)
+  {
+    service_impl_.template converting_move_construct<Protocol1>(
+        impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a sequenced packet socket implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Open a sequenced packet socket.
+  ASIO_SYNC_OP_VOID open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    if (protocol.type() == ASIO_OS_DEF(SOCK_SEQPACKET))
+      service_impl_.open(impl, protocol, ec);
+    else
+      ec = asio::error::invalid_argument;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native socket to a sequenced packet socket.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_socket,
+      asio::error_code& ec)
+  {
+    service_impl_.assign(impl, protocol, native_socket, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a sequenced packet socket implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Release ownership of the underlying socket.
+  native_handle_type release(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return service_impl_.release(impl, ec);
+  }
+
+  /// Get the native socket implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the socket.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.at_mark(impl, ec);
+  }
+
+  /// Determine the number of bytes available for reading.
+  std::size_t available(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.available(impl, ec);
+  }
+
+  /// Bind the sequenced packet socket to the specified local endpoint.
+  ASIO_SYNC_OP_VOID bind(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    service_impl_.bind(impl, endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Connect the sequenced packet socket to the specified endpoint.
+  ASIO_SYNC_OP_VOID connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    service_impl_.connect(impl, peer_endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous connect.
+  template <typename ConnectHandler>
+  ASIO_INITFN_RESULT_TYPE(ConnectHandler,
+      void (asio::error_code))
+  async_connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint,
+      ASIO_MOVE_ARG(ConnectHandler) handler)
+  {
+    async_completion<ConnectHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_connect(impl, peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Set a socket option.
+  template <typename SettableSocketOption>
+  ASIO_SYNC_OP_VOID set_option(implementation_type& impl,
+      const SettableSocketOption& option, asio::error_code& ec)
+  {
+    service_impl_.set_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get a socket option.
+  template <typename GettableSocketOption>
+  ASIO_SYNC_OP_VOID get_option(const implementation_type& impl,
+      GettableSocketOption& option, asio::error_code& ec) const
+  {
+    service_impl_.get_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the socket.
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(implementation_type& impl,
+      IoControlCommand& command, asio::error_code& ec)
+  {
+    service_impl_.io_control(impl, command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the socket.
+  bool non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the socket.
+  ASIO_SYNC_OP_VOID non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.native_non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the native socket implementation.
+  ASIO_SYNC_OP_VOID native_non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.native_non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.local_endpoint(impl, ec);
+  }
+
+  /// Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.remote_endpoint(impl, ec);
+  }
+
+  /// Disable sends or receives on the socket.
+  ASIO_SYNC_OP_VOID shutdown(implementation_type& impl,
+      socket_base::shutdown_type what, asio::error_code& ec)
+  {
+    service_impl_.shutdown(impl, what, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the socket to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  ASIO_SYNC_OP_VOID wait(implementation_type& impl,
+      socket_base::wait_type w, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the socket to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl, socket_base::wait_type w,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, w, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Send the given data to the peer.
+  template <typename ConstBufferSequence>
+  std::size_t send(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.send(impl, buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_send(impl, buffers, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Receive some data from the peer.
+  template <typename MutableBufferSequence>
+  std::size_t receive(implementation_type& impl,
+      const MutableBufferSequence& buffers, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags, asio::error_code& ec)
+  {
+    return service_impl_.receive_with_flags(impl,
+        buffers, in_flags, out_flags, ec);
+  }
+
+  /// Start an asynchronous receive.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(implementation_type& impl,
+      const MutableBufferSequence& buffers, socket_base::message_flags in_flags,
+      socket_base::message_flags& out_flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_receive_with_flags(impl,
+        buffers, in_flags, out_flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_SEQ_PACKET_SOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/serial_port.hpp b/subprojects/asio/include/asio/serial_port.hpp
new file mode 100644
index 000000000..27bb63ef7
--- /dev/null
+++ b/subprojects/asio/include/asio/serial_port.hpp
@@ -0,0 +1,769 @@
+//
+// serial_port.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SERIAL_PORT_HPP
+#define ASIO_SERIAL_PORT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_SERIAL_PORT) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <string>
+#include "asio/async_result.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/serial_port_base.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/basic_serial_port.hpp"
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+# if defined(ASIO_HAS_IOCP)
+#  include "asio/detail/win_iocp_serial_port_service.hpp"
+#  define ASIO_SVC_T detail::win_iocp_serial_port_service
+# else
+#  include "asio/detail/reactive_serial_port_service.hpp"
+#  define ASIO_SVC_T detail::reactive_serial_port_service
+# endif
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+// Typedef for the typical usage of a serial port.
+typedef basic_serial_port<> serial_port;
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+/// Provides serial port functionality.
+/**
+ * The serial_port class provides a wrapper over serial port functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class serial_port
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>,
+    public serial_port_base
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The native representation of a serial port.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef ASIO_SVC_T::native_handle_type native_handle_type;
+#endif
+
+  /// A basic_serial_port is always the lowest layer.
+  typedef serial_port lowest_layer_type;
+
+  /// Construct a serial_port without opening it.
+  /**
+   * This constructor creates a serial port without opening it.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   */
+  explicit serial_port(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Construct and open a serial_port.
+  /**
+   * This constructor creates and opens a serial port for the specified device
+   * name.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   *
+   * @param device The platform-specific device name for this serial
+   * port.
+   */
+  explicit serial_port(asio::io_context& io_context,
+      const char* device)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), device, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Construct and open a serial_port.
+  /**
+   * This constructor creates and opens a serial port for the specified device
+   * name.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   *
+   * @param device The platform-specific device name for this serial
+   * port.
+   */
+  explicit serial_port(asio::io_context& io_context,
+      const std::string& device)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), device, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Construct a serial_port on an existing native serial port.
+  /**
+   * This constructor creates a serial port object to hold an existing native
+   * serial port.
+   *
+   * @param io_context The io_context object that the serial port will use to
+   * dispatch handlers for any asynchronous operations performed on the port.
+   *
+   * @param native_serial_port A native serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  serial_port(asio::io_context& io_context,
+      const native_handle_type& native_serial_port)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_serial_port, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a serial_port from another.
+  /**
+   * This constructor moves a serial port from one object to another.
+   *
+   * @param other The other serial_port object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c serial_port(io_context&) constructor.
+   */
+  serial_port(serial_port&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign a serial_port from another.
+  /**
+   * This assignment operator moves a serial port from one object to another.
+   *
+   * @param other The other serial_port object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c serial_port(io_context&) constructor.
+   */
+  serial_port& operator=(serial_port&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroys the serial port.
+  /**
+   * This function destroys the serial port, cancelling any outstanding
+   * asynchronous wait operations associated with the serial port as if by
+   * calling @c cancel.
+   */
+  ~serial_port()
+  {
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since a serial_port cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since a serial_port cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+
+  /// Open the serial port using the specified device name.
+  /**
+   * This function opens the serial port for the specified device name.
+   *
+   * @param device The platform-specific device name.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void open(const std::string& device)
+  {
+    asio::error_code ec;
+    this->get_service().open(this->get_implementation(), device, ec);
+    asio::detail::throw_error(ec, "open");
+  }
+
+  /// Open the serial port using the specified device name.
+  /**
+   * This function opens the serial port using the given platform-specific
+   * device name.
+   *
+   * @param device The platform-specific device name.
+   *
+   * @param ec Set the indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID open(const std::string& device,
+      asio::error_code& ec)
+  {
+    this->get_service().open(this->get_implementation(), device, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native serial port to the serial port.
+  /*
+   * This function opens the serial port to hold an existing native serial port.
+   *
+   * @param native_serial_port A native serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const native_handle_type& native_serial_port)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(),
+        native_serial_port, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native serial port to the serial port.
+  /*
+   * This function opens the serial port to hold an existing native serial port.
+   *
+   * @param native_serial_port A native serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const native_handle_type& native_serial_port,
+      asio::error_code& ec)
+  {
+    this->get_service().assign(this->get_implementation(),
+        native_serial_port, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the serial port is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the serial port.
+  /**
+   * This function is used to close the serial port. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the serial port.
+  /**
+   * This function is used to close the serial port. Any asynchronous read or
+   * write operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native serial port representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * serial port. This is intended to allow access to native serial port
+   * functionality that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the serial port.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the serial port.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Send a break sequence to the serial port.
+  /**
+   * This function causes a break sequence of platform-specific duration to be
+   * sent out the serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void send_break()
+  {
+    asio::error_code ec;
+    this->get_service().send_break(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "send_break");
+  }
+
+  /// Send a break sequence to the serial port.
+  /**
+   * This function causes a break sequence of platform-specific duration to be
+   * sent out the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID send_break(asio::error_code& ec)
+  {
+    this->get_service().send_break(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Set an option on the serial port.
+  /**
+   * This function is used to set an option on the serial port.
+   *
+   * @param option The option value to be set on the serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa SettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename SettableSerialPortOption>
+  void set_option(const SettableSerialPortOption& option)
+  {
+    asio::error_code ec;
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "set_option");
+  }
+
+  /// Set an option on the serial port.
+  /**
+   * This function is used to set an option on the serial port.
+   *
+   * @param option The option value to be set on the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa SettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename SettableSerialPortOption>
+  ASIO_SYNC_OP_VOID set_option(const SettableSerialPortOption& option,
+      asio::error_code& ec)
+  {
+    this->get_service().set_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get an option from the serial port.
+  /**
+   * This function is used to get the current value of an option on the serial
+   * port.
+   *
+   * @param option The option value to be obtained from the serial port.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @sa GettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename GettableSerialPortOption>
+  void get_option(GettableSerialPortOption& option)
+  {
+    asio::error_code ec;
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    asio::detail::throw_error(ec, "get_option");
+  }
+
+  /// Get an option from the serial port.
+  /**
+   * This function is used to get the current value of an option on the serial
+   * port.
+   *
+   * @param option The option value to be obtained from the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @sa GettableSerialPortOption @n
+   * asio::serial_port_base::baud_rate @n
+   * asio::serial_port_base::flow_control @n
+   * asio::serial_port_base::parity @n
+   * asio::serial_port_base::stop_bits @n
+   * asio::serial_port_base::character_size
+   */
+  template <typename GettableSerialPortOption>
+  ASIO_SYNC_OP_VOID get_option(GettableSerialPortOption& option,
+      asio::error_code& ec)
+  {
+    this->get_service().get_option(this->get_implementation(), option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Write some data to the serial port.
+  /**
+   * This function is used to write data to the serial port. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the serial port.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.write_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return s;
+  }
+
+  /// Write some data to the serial port.
+  /**
+   * This function is used to write data to the serial port. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the serial port.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write data to the serial port.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be written to the serial port.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.async_write_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_write_some(
+        this->get_implementation(), buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the serial port.
+  /**
+   * This function is used to read data from the serial port. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.read_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return s;
+  }
+
+  /// Read some data from the serial port.
+  /**
+   * This function is used to read data from the serial port. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read data from the serial port.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read function if you need to ensure that the
+   * requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * serial_port.async_read_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_read_some(
+        this->get_implementation(), buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+};
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+# undef ASIO_SVC_T
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // defined(ASIO_HAS_SERIAL_PORT)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_SERIAL_PORT_HPP
diff --git a/subprojects/asio/include/asio/serial_port_base.hpp b/subprojects/asio/include/asio/serial_port_base.hpp
new file mode 100644
index 000000000..feb5b9df8
--- /dev/null
+++ b/subprojects/asio/include/asio/serial_port_base.hpp
@@ -0,0 +1,167 @@
+//
+// serial_port_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2008 Rep Invariant Systems, Inc. (info@repinvariant.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SERIAL_PORT_BASE_HPP
+#define ASIO_SERIAL_PORT_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_SERIAL_PORT) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+# include <termios.h>
+#endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
+
+#include "asio/detail/socket_types.hpp"
+#include "asio/error_code.hpp"
+
+#if defined(GENERATING_DOCUMENTATION)
+# define ASIO_OPTION_STORAGE implementation_defined
+#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+# define ASIO_OPTION_STORAGE DCB
+#else
+# define ASIO_OPTION_STORAGE termios
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// The serial_port_base class is used as a base for the basic_serial_port class
+/// template so that we have a common place to define the serial port options.
+class serial_port_base
+{
+public:
+  /// Serial port option to permit changing the baud rate.
+  /**
+   * Implements changing the baud rate for a given serial port.
+   */
+  class baud_rate
+  {
+  public:
+    explicit baud_rate(unsigned int rate = 0);
+    unsigned int value() const;
+    ASIO_DECL ASIO_SYNC_OP_VOID store(
+        ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec) const;
+    ASIO_DECL ASIO_SYNC_OP_VOID load(
+        const ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec);
+  private:
+    unsigned int value_;
+  };
+
+  /// Serial port option to permit changing the flow control.
+  /**
+   * Implements changing the flow control for a given serial port.
+   */
+  class flow_control
+  {
+  public:
+    enum type { none, software, hardware };
+    ASIO_DECL explicit flow_control(type t = none);
+    type value() const;
+    ASIO_DECL ASIO_SYNC_OP_VOID store(
+        ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec) const;
+    ASIO_DECL ASIO_SYNC_OP_VOID load(
+        const ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec);
+  private:
+    type value_;
+  };
+
+  /// Serial port option to permit changing the parity.
+  /**
+   * Implements changing the parity for a given serial port.
+   */
+  class parity
+  {
+  public:
+    enum type { none, odd, even };
+    ASIO_DECL explicit parity(type t = none);
+    type value() const;
+    ASIO_DECL ASIO_SYNC_OP_VOID store(
+        ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec) const;
+    ASIO_DECL ASIO_SYNC_OP_VOID load(
+        const ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec);
+  private:
+    type value_;
+  };
+
+  /// Serial port option to permit changing the number of stop bits.
+  /**
+   * Implements changing the number of stop bits for a given serial port.
+   */
+  class stop_bits
+  {
+  public:
+    enum type { one, onepointfive, two };
+    ASIO_DECL explicit stop_bits(type t = one);
+    type value() const;
+    ASIO_DECL ASIO_SYNC_OP_VOID store(
+        ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec) const;
+    ASIO_DECL ASIO_SYNC_OP_VOID load(
+        const ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec);
+  private:
+    type value_;
+  };
+
+  /// Serial port option to permit changing the character size.
+  /**
+   * Implements changing the character size for a given serial port.
+   */
+  class character_size
+  {
+  public:
+    ASIO_DECL explicit character_size(unsigned int t = 8);
+    unsigned int value() const;
+    ASIO_DECL ASIO_SYNC_OP_VOID store(
+        ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec) const;
+    ASIO_DECL ASIO_SYNC_OP_VOID load(
+        const ASIO_OPTION_STORAGE& storage,
+        asio::error_code& ec);
+  private:
+    unsigned int value_;
+  };
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~serial_port_base()
+  {
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#undef ASIO_OPTION_STORAGE
+
+#include "asio/impl/serial_port_base.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/serial_port_base.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // defined(ASIO_HAS_SERIAL_PORT)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_SERIAL_PORT_BASE_HPP
diff --git a/subprojects/asio/include/asio/serial_port_service.hpp b/subprojects/asio/include/asio/serial_port_service.hpp
new file mode 100644
index 000000000..0e20d96e3
--- /dev/null
+++ b/subprojects/asio/include/asio/serial_port_service.hpp
@@ -0,0 +1,249 @@
+//
+// serial_port_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SERIAL_PORT_SERVICE_HPP
+#define ASIO_SERIAL_PORT_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_SERIAL_PORT) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include <string>
+#include "asio/async_result.hpp"
+#include "asio/detail/reactive_serial_port_service.hpp"
+#include "asio/detail/win_iocp_serial_port_service.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+#include "asio/serial_port_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a serial port.
+class serial_port_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<serial_port_service>
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+private:
+  // The type of the platform-specific implementation.
+#if defined(ASIO_HAS_IOCP)
+  typedef detail::win_iocp_serial_port_service service_impl_type;
+#else
+  typedef detail::reactive_serial_port_service service_impl_type;
+#endif
+
+public:
+  /// The type of a serial port implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native handle type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new serial port service for the specified io_context.
+  explicit serial_port_service(asio::io_context& io_context)
+    : asio::detail::service_base<serial_port_service>(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new serial port implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new serial port implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another serial port implementation.
+  void move_assign(implementation_type& impl,
+      serial_port_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a serial port implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Open a serial port.
+  ASIO_SYNC_OP_VOID open(implementation_type& impl,
+      const std::string& device, asio::error_code& ec)
+  {
+    service_impl_.open(impl, device, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native handle to a serial port.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const native_handle_type& handle, asio::error_code& ec)
+  {
+    service_impl_.assign(impl, handle, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the handle is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a serial port implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native handle implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Set a serial port option.
+  template <typename SettableSerialPortOption>
+  ASIO_SYNC_OP_VOID set_option(implementation_type& impl,
+      const SettableSerialPortOption& option, asio::error_code& ec)
+  {
+    service_impl_.set_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get a serial port option.
+  template <typename GettableSerialPortOption>
+  ASIO_SYNC_OP_VOID get_option(const implementation_type& impl,
+      GettableSerialPortOption& option, asio::error_code& ec) const
+  {
+    service_impl_.get_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Send a break sequence to the serial port.
+  ASIO_SYNC_OP_VOID send_break(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.send_break(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Write the given data to the stream.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.write_some(impl, buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_write_some(impl, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the stream.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.read_some(impl, buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_read_some(impl, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_SERIAL_PORT)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_SERIAL_PORT_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/signal_set.hpp b/subprojects/asio/include/asio/signal_set.hpp
new file mode 100644
index 000000000..30e5c4e39
--- /dev/null
+++ b/subprojects/asio/include/asio/signal_set.hpp
@@ -0,0 +1,447 @@
+//
+// signal_set.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SIGNAL_SET_HPP
+#define ASIO_SIGNAL_SET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/async_result.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/basic_signal_set.hpp"
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/detail/signal_set_service.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+namespace asio {
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+// Typedef for the typical usage of a signal set.
+typedef basic_signal_set<> signal_set;
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+/// Provides signal functionality.
+/**
+ * The signal_set class provides the ability to perform an asynchronous wait
+ * for one or more signals to occur.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Example
+ * Performing an asynchronous wait:
+ * @code
+ * void handler(
+ *     const asio::error_code& error,
+ *     int signal_number)
+ * {
+ *   if (!error)
+ *   {
+ *     // A signal occurred.
+ *   }
+ * }
+ *
+ * ...
+ *
+ * // Construct a signal set registered for process termination.
+ * asio::signal_set signals(io_context, SIGINT, SIGTERM);
+ *
+ * // Start an asynchronous wait for one of the signals to occur.
+ * signals.async_wait(handler);
+ * @endcode
+ *
+ * @par Queueing of signal notifications
+ *
+ * If a signal is registered with a signal_set, and the signal occurs when
+ * there are no waiting handlers, then the signal notification is queued. The
+ * next async_wait operation on that signal_set will dequeue the notification.
+ * If multiple notifications are queued, subsequent async_wait operations
+ * dequeue them one at a time. Signal notifications are dequeued in order of
+ * ascending signal number.
+ *
+ * If a signal number is removed from a signal_set (using the @c remove or @c
+ * erase member functions) then any queued notifications for that signal are
+ * discarded.
+ *
+ * @par Multiple registration of signals
+ *
+ * The same signal number may be registered with different signal_set objects.
+ * When the signal occurs, one handler is called for each signal_set object.
+ *
+ * Note that multiple registration only works for signals that are registered
+ * using Asio. The application must not also register a signal handler using
+ * functions such as @c signal() or @c sigaction().
+ *
+ * @par Signal masking on POSIX platforms
+ *
+ * POSIX allows signals to be blocked using functions such as @c sigprocmask()
+ * and @c pthread_sigmask(). For signals to be delivered, programs must ensure
+ * that any signals registered using signal_set objects are unblocked in at
+ * least one thread.
+ */
+class signal_set
+  : ASIO_SVC_ACCESS basic_io_object<detail::signal_set_service>
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// Construct a signal set without adding any signals.
+  /**
+   * This constructor creates a signal set without registering for any signals.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   */
+  explicit signal_set(asio::io_context& io_context)
+    : basic_io_object<detail::signal_set_service>(io_context)
+  {
+  }
+
+  /// Construct a signal set and add one signal.
+  /**
+   * This constructor creates a signal set and registers for one signal.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   *
+   * @param signal_number_1 The signal number to be added.
+   *
+   * @note This constructor is equivalent to performing:
+   * @code asio::signal_set signals(io_context);
+   * signals.add(signal_number_1); @endcode
+   */
+  signal_set(asio::io_context& io_context, int signal_number_1)
+    : basic_io_object<detail::signal_set_service>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number_1, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Construct a signal set and add two signals.
+  /**
+   * This constructor creates a signal set and registers for two signals.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   *
+   * @param signal_number_1 The first signal number to be added.
+   *
+   * @param signal_number_2 The second signal number to be added.
+   *
+   * @note This constructor is equivalent to performing:
+   * @code asio::signal_set signals(io_context);
+   * signals.add(signal_number_1);
+   * signals.add(signal_number_2); @endcode
+   */
+  signal_set(asio::io_context& io_context, int signal_number_1,
+      int signal_number_2)
+    : basic_io_object<detail::signal_set_service>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number_1, ec);
+    asio::detail::throw_error(ec, "add");
+    this->get_service().add(this->get_implementation(), signal_number_2, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Construct a signal set and add three signals.
+  /**
+   * This constructor creates a signal set and registers for three signals.
+   *
+   * @param io_context The io_context object that the signal set will use to
+   * dispatch handlers for any asynchronous operations performed on the set.
+   *
+   * @param signal_number_1 The first signal number to be added.
+   *
+   * @param signal_number_2 The second signal number to be added.
+   *
+   * @param signal_number_3 The third signal number to be added.
+   *
+   * @note This constructor is equivalent to performing:
+   * @code asio::signal_set signals(io_context);
+   * signals.add(signal_number_1);
+   * signals.add(signal_number_2);
+   * signals.add(signal_number_3); @endcode
+   */
+  signal_set(asio::io_context& io_context, int signal_number_1,
+      int signal_number_2, int signal_number_3)
+    : basic_io_object<detail::signal_set_service>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number_1, ec);
+    asio::detail::throw_error(ec, "add");
+    this->get_service().add(this->get_implementation(), signal_number_2, ec);
+    asio::detail::throw_error(ec, "add");
+    this->get_service().add(this->get_implementation(), signal_number_3, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Destroys the signal set.
+  /**
+   * This function destroys the signal set, cancelling any outstanding
+   * asynchronous wait operations associated with the signal set as if by
+   * calling @c cancel.
+   */
+  ~signal_set()
+  {
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<detail::signal_set_service>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<detail::signal_set_service>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<detail::signal_set_service>::get_executor();
+  }
+
+  /// Add a signal to a signal_set.
+  /**
+   * This function adds the specified signal to the set. It has no effect if the
+   * signal is already in the set.
+   *
+   * @param signal_number The signal to be added to the set.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void add(int signal_number)
+  {
+    asio::error_code ec;
+    this->get_service().add(this->get_implementation(), signal_number, ec);
+    asio::detail::throw_error(ec, "add");
+  }
+
+  /// Add a signal to a signal_set.
+  /**
+   * This function adds the specified signal to the set. It has no effect if the
+   * signal is already in the set.
+   *
+   * @param signal_number The signal to be added to the set.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID add(int signal_number,
+      asio::error_code& ec)
+  {
+    this->get_service().add(this->get_implementation(), signal_number, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Remove a signal from a signal_set.
+  /**
+   * This function removes the specified signal from the set. It has no effect
+   * if the signal is not in the set.
+   *
+   * @param signal_number The signal to be removed from the set.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Removes any notifications that have been queued for the specified
+   * signal number.
+   */
+  void remove(int signal_number)
+  {
+    asio::error_code ec;
+    this->get_service().remove(this->get_implementation(), signal_number, ec);
+    asio::detail::throw_error(ec, "remove");
+  }
+
+  /// Remove a signal from a signal_set.
+  /**
+   * This function removes the specified signal from the set. It has no effect
+   * if the signal is not in the set.
+   *
+   * @param signal_number The signal to be removed from the set.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Removes any notifications that have been queued for the specified
+   * signal number.
+   */
+  ASIO_SYNC_OP_VOID remove(int signal_number,
+      asio::error_code& ec)
+  {
+    this->get_service().remove(this->get_implementation(), signal_number, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Remove all signals from a signal_set.
+  /**
+   * This function removes all signals from the set. It has no effect if the set
+   * is already empty.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Removes all queued notifications.
+   */
+  void clear()
+  {
+    asio::error_code ec;
+    this->get_service().clear(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "clear");
+  }
+
+  /// Remove all signals from a signal_set.
+  /**
+   * This function removes all signals from the set. It has no effect if the set
+   * is already empty.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Removes all queued notifications.
+   */
+  ASIO_SYNC_OP_VOID clear(asio::error_code& ec)
+  {
+    this->get_service().clear(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Cancel all operations associated with the signal set.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the signal set. The handler for each cancelled
+   * operation will be invoked with the asio::error::operation_aborted
+   * error code.
+   *
+   * Cancellation does not alter the set of registered signals.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note If a registered signal occurred before cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all operations associated with the signal set.
+  /**
+   * This function forces the completion of any pending asynchronous wait
+   * operations against the signal set. The handler for each cancelled
+   * operation will be invoked with the asio::error::operation_aborted
+   * error code.
+   *
+   * Cancellation does not alter the set of registered signals.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note If a registered signal occurred before cancel() is called, then the
+   * handlers for asynchronous wait operations will:
+   *
+   * @li have already been invoked; or
+   *
+   * @li have been queued for invocation in the near future.
+   *
+   * These handlers can no longer be cancelled, and therefore are passed an
+   * error code that indicates the successful completion of the wait operation.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous operation to wait for a signal to be delivered.
+  /**
+   * This function may be used to initiate an asynchronous wait against the
+   * signal set. It always returns immediately.
+   *
+   * For each call to async_wait(), the supplied handler will be called exactly
+   * once. The handler will be called when:
+   *
+   * @li One of the registered signals in the signal set occurs; or
+   *
+   * @li The signal set was cancelled, in which case the handler is passed the
+   * error code asio::error::operation_aborted.
+   *
+   * @param handler The handler to be called when the signal occurs. Copies
+   * will be made of the handler as required. The function signature of the
+   * handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   int signal_number // Indicates which signal occurred.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename SignalHandler>
+  ASIO_INITFN_RESULT_TYPE(SignalHandler,
+      void (asio::error_code, int))
+  async_wait(ASIO_MOVE_ARG(SignalHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a SignalHandler.
+    ASIO_SIGNAL_HANDLER_CHECK(SignalHandler, handler) type_check;
+
+    async_completion<SignalHandler,
+      void (asio::error_code, int)> init(handler);
+
+    this->get_service().async_wait(this->get_implementation(),
+        init.completion_handler);
+
+    return init.result.get();
+  }
+};
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+} // namespace asio
+
+#endif // ASIO_SIGNAL_SET_HPP
diff --git a/subprojects/asio/include/asio/signal_set_service.hpp b/subprojects/asio/include/asio/signal_set_service.hpp
new file mode 100644
index 000000000..3285beb00
--- /dev/null
+++ b/subprojects/asio/include/asio/signal_set_service.hpp
@@ -0,0 +1,142 @@
+//
+// signal_set_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SIGNAL_SET_SERVICE_HPP
+#define ASIO_SIGNAL_SET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/async_result.hpp"
+#include "asio/detail/signal_set_service.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a signal set.
+class signal_set_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<signal_set_service>
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+public:
+  /// The type of a signal set implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef detail::signal_set_service::implementation_type implementation_type;
+#endif
+
+  /// Construct a new signal set service for the specified io_context.
+  explicit signal_set_service(asio::io_context& io_context)
+    : asio::detail::service_base<signal_set_service>(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new signal set implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+  /// Destroy a signal set implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Add a signal to a signal_set.
+  ASIO_SYNC_OP_VOID add(implementation_type& impl,
+      int signal_number, asio::error_code& ec)
+  {
+    service_impl_.add(impl, signal_number, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Remove a signal to a signal_set.
+  ASIO_SYNC_OP_VOID remove(implementation_type& impl,
+      int signal_number, asio::error_code& ec)
+  {
+    service_impl_.remove(impl, signal_number, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Remove all signals from a signal_set.
+  ASIO_SYNC_OP_VOID clear(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.clear(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Cancel all operations associated with the signal set.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  // Start an asynchronous operation to wait for a signal to be delivered.
+  template <typename SignalHandler>
+  ASIO_INITFN_RESULT_TYPE(SignalHandler,
+      void (asio::error_code, int))
+  async_wait(implementation_type& impl,
+      ASIO_MOVE_ARG(SignalHandler) handler)
+  {
+    async_completion<SignalHandler,
+      void (asio::error_code, int)> init(handler);
+
+    service_impl_.async_wait(impl, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // Perform any fork-related housekeeping.
+  void notify_fork(asio::io_context::fork_event event)
+  {
+    service_impl_.notify_fork(event);
+  }
+
+  // The platform-specific implementation.
+  detail::signal_set_service service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_SIGNAL_SET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/socket_acceptor_service.hpp b/subprojects/asio/include/asio/socket_acceptor_service.hpp
new file mode 100644
index 000000000..cd40fe142
--- /dev/null
+++ b/subprojects/asio/include/asio/socket_acceptor_service.hpp
@@ -0,0 +1,372 @@
+//
+// socket_acceptor_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SOCKET_ACCEPTOR_SERVICE_HPP
+#define ASIO_SOCKET_ACCEPTOR_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/basic_socket.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/null_socket_service.hpp"
+#elif defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_socket_service.hpp"
+#else
+# include "asio/detail/reactive_socket_service.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a socket acceptor.
+template <typename Protocol>
+class socket_acceptor_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<socket_acceptor_service<Protocol> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename protocol_type::endpoint endpoint_type;
+
+private:
+  // The type of the platform-specific implementation.
+#if defined(ASIO_WINDOWS_RUNTIME)
+  typedef detail::null_socket_service<Protocol> service_impl_type;
+#elif defined(ASIO_HAS_IOCP)
+  typedef detail::win_iocp_socket_service<Protocol> service_impl_type;
+#else
+  typedef detail::reactive_socket_service<Protocol> service_impl_type;
+#endif
+
+public:
+  /// The native type of the socket acceptor.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native acceptor type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new socket acceptor service for the specified io_context.
+  explicit socket_acceptor_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        socket_acceptor_service<Protocol> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new socket acceptor implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new socket acceptor implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another socket acceptor implementation.
+  void move_assign(implementation_type& impl,
+      socket_acceptor_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+
+  // All acceptor services have access to each other's implementations.
+  template <typename Protocol1> friend class socket_acceptor_service;
+
+  /// Move-construct a new socket acceptor implementation from another protocol
+  /// type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      socket_acceptor_service<Protocol1>& other_service,
+      typename socket_acceptor_service<
+        Protocol1>::implementation_type& other_impl,
+      typename enable_if<is_convertible<
+        Protocol1, Protocol>::value>::type* = 0)
+  {
+    service_impl_.template converting_move_construct<Protocol1>(
+        impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a socket acceptor implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Open a new socket acceptor implementation.
+  ASIO_SYNC_OP_VOID open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    service_impl_.open(impl, protocol, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native acceptor to a socket acceptor.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_acceptor,
+      asio::error_code& ec)
+  {
+    service_impl_.assign(impl, protocol, native_acceptor, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the acceptor is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the acceptor.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Bind the socket acceptor to the specified local endpoint.
+  ASIO_SYNC_OP_VOID bind(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    service_impl_.bind(impl, endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Place the socket acceptor into the state where it will listen for new
+  /// connections.
+  ASIO_SYNC_OP_VOID listen(implementation_type& impl, int backlog,
+      asio::error_code& ec)
+  {
+    service_impl_.listen(impl, backlog, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Close a socket acceptor implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Release ownership of the underlying acceptor.
+  native_handle_type release(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return service_impl_.release(impl, ec);
+  }
+
+  /// Get the native acceptor implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Set a socket option.
+  template <typename SettableSocketOption>
+  ASIO_SYNC_OP_VOID set_option(implementation_type& impl,
+      const SettableSocketOption& option, asio::error_code& ec)
+  {
+    service_impl_.set_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get a socket option.
+  template <typename GettableSocketOption>
+  ASIO_SYNC_OP_VOID get_option(const implementation_type& impl,
+      GettableSocketOption& option, asio::error_code& ec) const
+  {
+    service_impl_.get_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the socket.
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(implementation_type& impl,
+      IoControlCommand& command, asio::error_code& ec)
+  {
+    service_impl_.io_control(impl, command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the acceptor.
+  bool non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the acceptor.
+  ASIO_SYNC_OP_VOID non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native acceptor implementation.
+  bool native_non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.native_non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the native acceptor implementation.
+  ASIO_SYNC_OP_VOID native_non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.native_non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.local_endpoint(impl, ec);
+  }
+
+  /// Wait for the acceptor to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  ASIO_SYNC_OP_VOID wait(implementation_type& impl,
+      socket_base::wait_type w, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the acceptor to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl, socket_base::wait_type w,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, w, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Accept a new connection.
+  template <typename Protocol1, typename SocketService>
+  ASIO_SYNC_OP_VOID accept(implementation_type& impl,
+      basic_socket<Protocol1, SocketService>& peer,
+      endpoint_type* peer_endpoint, asio::error_code& ec,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+  {
+    service_impl_.accept(impl, peer, peer_endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Accept a new connection.
+  typename Protocol::socket accept(implementation_type& impl,
+      io_context* peer_io_context, endpoint_type* peer_endpoint,
+      asio::error_code& ec)
+  {
+    return service_impl_.accept(impl, peer_io_context, peer_endpoint, ec);
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  /// Start an asynchronous accept.
+  template <typename Protocol1, typename SocketService, typename AcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(AcceptHandler,
+      void (asio::error_code))
+  async_accept(implementation_type& impl,
+      basic_socket<Protocol1, SocketService>& peer,
+      endpoint_type* peer_endpoint,
+      ASIO_MOVE_ARG(AcceptHandler) handler,
+      typename enable_if<is_convertible<Protocol, Protocol1>::value>::type* = 0)
+  {
+    async_completion<AcceptHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_accept(impl,
+        peer, peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  /// Start an asynchronous accept.
+  template <typename MoveAcceptHandler>
+  ASIO_INITFN_RESULT_TYPE(MoveAcceptHandler,
+      void (asio::error_code, typename Protocol::socket))
+  async_accept(implementation_type& impl,
+      asio::io_context* peer_io_context, endpoint_type* peer_endpoint,
+      ASIO_MOVE_ARG(MoveAcceptHandler) handler)
+  {
+    async_completion<MoveAcceptHandler,
+      void (asio::error_code,
+        typename Protocol::socket)> init(handler);
+
+    service_impl_.async_accept(impl,
+        peer_io_context, peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_SOCKET_ACCEPTOR_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/socket_base.hpp b/subprojects/asio/include/asio/socket_base.hpp
new file mode 100644
index 000000000..87ed8408b
--- /dev/null
+++ b/subprojects/asio/include/asio/socket_base.hpp
@@ -0,0 +1,559 @@
+//
+// socket_base.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SOCKET_BASE_HPP
+#define ASIO_SOCKET_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/io_control.hpp"
+#include "asio/detail/socket_option.hpp"
+#include "asio/detail/socket_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// The socket_base class is used as a base for the basic_stream_socket and
+/// basic_datagram_socket class templates so that we have a common place to
+/// define the shutdown_type and enum.
+class socket_base
+{
+public:
+  /// Different ways a socket may be shutdown.
+  enum shutdown_type
+  {
+#if defined(GENERATING_DOCUMENTATION)
+    /// Shutdown the receive side of the socket.
+    shutdown_receive = implementation_defined,
+
+    /// Shutdown the send side of the socket.
+    shutdown_send = implementation_defined,
+
+    /// Shutdown both send and receive on the socket.
+    shutdown_both = implementation_defined
+#else
+    shutdown_receive = ASIO_OS_DEF(SHUT_RD),
+    shutdown_send = ASIO_OS_DEF(SHUT_WR),
+    shutdown_both = ASIO_OS_DEF(SHUT_RDWR)
+#endif
+  };
+
+  /// Bitmask type for flags that can be passed to send and receive operations.
+  typedef int message_flags;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// Peek at incoming data without removing it from the input queue.
+  static const int message_peek = implementation_defined;
+
+  /// Process out-of-band data.
+  static const int message_out_of_band = implementation_defined;
+
+  /// Specify that the data should not be subject to routing.
+  static const int message_do_not_route = implementation_defined;
+
+  /// Specifies that the data marks the end of a record.
+  static const int message_end_of_record = implementation_defined;
+#else
+  ASIO_STATIC_CONSTANT(int,
+      message_peek = ASIO_OS_DEF(MSG_PEEK));
+  ASIO_STATIC_CONSTANT(int,
+      message_out_of_band = ASIO_OS_DEF(MSG_OOB));
+  ASIO_STATIC_CONSTANT(int,
+      message_do_not_route = ASIO_OS_DEF(MSG_DONTROUTE));
+  ASIO_STATIC_CONSTANT(int,
+      message_end_of_record = ASIO_OS_DEF(MSG_EOR));
+#endif
+
+  /// Wait types.
+  /**
+   * For use with basic_socket::wait() and basic_socket::async_wait().
+   */
+  enum wait_type
+  {
+    /// Wait for a socket to become ready to read.
+    wait_read,
+
+    /// Wait for a socket to become ready to write.
+    wait_write,
+
+    /// Wait for a socket to have error conditions pending.
+    wait_error
+  };
+
+  /// Socket option to permit sending of broadcast messages.
+  /**
+   * Implements the SOL_SOCKET/SO_BROADCAST socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::udp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::broadcast option(true);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::udp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::broadcast option;
+   * socket.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined broadcast;
+#else
+  typedef asio::detail::socket_option::boolean<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_BROADCAST)>
+      broadcast;
+#endif
+
+  /// Socket option to enable socket-level debugging.
+  /**
+   * Implements the SOL_SOCKET/SO_DEBUG socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::debug option(true);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::debug option;
+   * socket.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined debug;
+#else
+  typedef asio::detail::socket_option::boolean<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_DEBUG)> debug;
+#endif
+
+  /// Socket option to prevent routing, use local interfaces only.
+  /**
+   * Implements the SOL_SOCKET/SO_DONTROUTE socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::udp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::do_not_route option(true);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::udp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::do_not_route option;
+   * socket.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined do_not_route;
+#else
+  typedef asio::detail::socket_option::boolean<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_DONTROUTE)>
+      do_not_route;
+#endif
+
+  /// Socket option to send keep-alives.
+  /**
+   * Implements the SOL_SOCKET/SO_KEEPALIVE socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::keep_alive option(true);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::keep_alive option;
+   * socket.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined keep_alive;
+#else
+  typedef asio::detail::socket_option::boolean<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_KEEPALIVE)> keep_alive;
+#endif
+
+  /// Socket option for the send buffer size of a socket.
+  /**
+   * Implements the SOL_SOCKET/SO_SNDBUF socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::send_buffer_size option(8192);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::send_buffer_size option;
+   * socket.get_option(option);
+   * int size = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Integer_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined send_buffer_size;
+#else
+  typedef asio::detail::socket_option::integer<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_SNDBUF)>
+      send_buffer_size;
+#endif
+
+  /// Socket option for the send low watermark.
+  /**
+   * Implements the SOL_SOCKET/SO_SNDLOWAT socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::send_low_watermark option(1024);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::send_low_watermark option;
+   * socket.get_option(option);
+   * int size = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Integer_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined send_low_watermark;
+#else
+  typedef asio::detail::socket_option::integer<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_SNDLOWAT)>
+      send_low_watermark;
+#endif
+
+  /// Socket option for the receive buffer size of a socket.
+  /**
+   * Implements the SOL_SOCKET/SO_RCVBUF socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::receive_buffer_size option(8192);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::receive_buffer_size option;
+   * socket.get_option(option);
+   * int size = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Integer_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined receive_buffer_size;
+#else
+  typedef asio::detail::socket_option::integer<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_RCVBUF)>
+      receive_buffer_size;
+#endif
+
+  /// Socket option for the receive low watermark.
+  /**
+   * Implements the SOL_SOCKET/SO_RCVLOWAT socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::receive_low_watermark option(1024);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::receive_low_watermark option;
+   * socket.get_option(option);
+   * int size = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Integer_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined receive_low_watermark;
+#else
+  typedef asio::detail::socket_option::integer<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_RCVLOWAT)>
+      receive_low_watermark;
+#endif
+
+  /// Socket option to allow the socket to be bound to an address that is
+  /// already in use.
+  /**
+   * Implements the SOL_SOCKET/SO_REUSEADDR socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context); 
+   * ...
+   * asio::socket_base::reuse_address option(true);
+   * acceptor.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context); 
+   * ...
+   * asio::socket_base::reuse_address option;
+   * acceptor.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined reuse_address;
+#else
+  typedef asio::detail::socket_option::boolean<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_REUSEADDR)>
+      reuse_address;
+#endif
+
+  /// Socket option to specify whether the socket lingers on close if unsent
+  /// data is present.
+  /**
+   * Implements the SOL_SOCKET/SO_LINGER socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::linger option(true, 30);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::linger option;
+   * socket.get_option(option);
+   * bool is_set = option.enabled();
+   * unsigned short timeout = option.timeout();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Linger_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined linger;
+#else
+  typedef asio::detail::socket_option::linger<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_LINGER)>
+      linger;
+#endif
+
+  /// Socket option for putting received out-of-band data inline.
+  /**
+   * Implements the SOL_SOCKET/SO_OOBINLINE socket option.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::socket_base::out_of_band_inline option(true);
+   * socket.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::socket socket(io_context);
+   * ...
+   * asio::socket_base::out_of_band_inline option;
+   * socket.get_option(option);
+   * bool value = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined out_of_band_inline;
+#else
+  typedef asio::detail::socket_option::boolean<
+    ASIO_OS_DEF(SOL_SOCKET), ASIO_OS_DEF(SO_OOBINLINE)>
+      out_of_band_inline;
+#endif
+
+  /// Socket option to report aborted connections on accept.
+  /**
+   * Implements a custom socket option that determines whether or not an accept
+   * operation is permitted to fail with asio::error::connection_aborted.
+   * By default the option is false.
+   *
+   * @par Examples
+   * Setting the option:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context); 
+   * ...
+   * asio::socket_base::enable_connection_aborted option(true);
+   * acceptor.set_option(option);
+   * @endcode
+   *
+   * @par
+   * Getting the current option value:
+   * @code
+   * asio::ip::tcp::acceptor acceptor(io_context); 
+   * ...
+   * asio::socket_base::enable_connection_aborted option;
+   * acceptor.get_option(option);
+   * bool is_set = option.value();
+   * @endcode
+   *
+   * @par Concepts:
+   * Socket_Option, Boolean_Socket_Option.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined enable_connection_aborted;
+#else
+  typedef asio::detail::socket_option::boolean<
+    asio::detail::custom_socket_option_level,
+    asio::detail::enable_connection_aborted_option>
+    enable_connection_aborted;
+#endif
+
+  /// IO control command to get the amount of data that can be read without
+  /// blocking.
+  /**
+   * Implements the FIONREAD IO control command.
+   *
+   * @par Example
+   * @code
+   * asio::ip::tcp::socket socket(io_context); 
+   * ...
+   * asio::socket_base::bytes_readable command(true);
+   * socket.io_control(command);
+   * std::size_t bytes_readable = command.get();
+   * @endcode
+   *
+   * @par Concepts:
+   * IO_Control_Command, Size_IO_Control_Command.
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined bytes_readable;
+#else
+  typedef asio::detail::io_control::bytes_readable bytes_readable;
+#endif
+
+  /// The maximum length of the queue of pending incoming connections.
+#if defined(GENERATING_DOCUMENTATION)
+  static const int max_listen_connections = implementation_defined;
+#else
+  ASIO_STATIC_CONSTANT(int, max_listen_connections
+      = ASIO_OS_DEF(SOMAXCONN));
+#endif
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use max_listen_connections.) The maximum length of the queue
+  /// of pending incoming connections.
+#if defined(GENERATING_DOCUMENTATION)
+  static const int max_connections = implementation_defined;
+#else
+  ASIO_STATIC_CONSTANT(int, max_connections
+      = ASIO_OS_DEF(SOMAXCONN));
+#endif
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~socket_base()
+  {
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SOCKET_BASE_HPP
diff --git a/subprojects/asio/include/asio/spawn.hpp b/subprojects/asio/include/asio/spawn.hpp
new file mode 100644
index 000000000..a91c5815f
--- /dev/null
+++ b/subprojects/asio/include/asio/spawn.hpp
@@ -0,0 +1,336 @@
+//
+// spawn.hpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SPAWN_HPP
+#define ASIO_SPAWN_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <boost/coroutine/all.hpp>
+#include "asio/bind_executor.hpp"
+#include "asio/detail/memory.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/detail/wrapped_handler.hpp"
+#include "asio/executor.hpp"
+#include "asio/io_context.hpp"
+#include "asio/is_executor.hpp"
+#include "asio/strand.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Context object the represents the currently executing coroutine.
+/**
+ * The basic_yield_context class is used to represent the currently executing
+ * stackful coroutine. A basic_yield_context may be passed as a handler to an
+ * asynchronous operation. For example:
+ *
+ * @code template <typename Handler>
+ * void my_coroutine(basic_yield_context<Handler> yield)
+ * {
+ *   ...
+ *   std::size_t n = my_socket.async_read_some(buffer, yield);
+ *   ...
+ * } @endcode
+ *
+ * The initiating function (async_read_some in the above example) suspends the
+ * current coroutine. The coroutine is resumed when the asynchronous operation
+ * completes, and the result of the operation is returned.
+ */
+template <typename Handler>
+class basic_yield_context
+{
+public:
+  /// The coroutine callee type, used by the implementation.
+  /**
+   * When using Boost.Coroutine v1, this type is:
+   * @code typename coroutine<void()> @endcode
+   * When using Boost.Coroutine v2 (unidirectional coroutines), this type is:
+   * @code push_coroutine<void> @endcode
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined callee_type;
+#elif defined(BOOST_COROUTINES_UNIDIRECT) || defined(BOOST_COROUTINES_V2)
+  typedef boost::coroutines::push_coroutine<void> callee_type;
+#else
+  typedef boost::coroutines::coroutine<void()> callee_type;
+#endif
+  
+  /// The coroutine caller type, used by the implementation.
+  /**
+   * When using Boost.Coroutine v1, this type is:
+   * @code typename coroutine<void()>::caller_type @endcode
+   * When using Boost.Coroutine v2 (unidirectional coroutines), this type is:
+   * @code pull_coroutine<void> @endcode
+   */
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined caller_type;
+#elif defined(BOOST_COROUTINES_UNIDIRECT) || defined(BOOST_COROUTINES_V2)
+  typedef boost::coroutines::pull_coroutine<void> caller_type;
+#else
+  typedef boost::coroutines::coroutine<void()>::caller_type caller_type;
+#endif
+
+  /// Construct a yield context to represent the specified coroutine.
+  /**
+   * Most applications do not need to use this constructor. Instead, the
+   * spawn() function passes a yield context as an argument to the coroutine
+   * function.
+   */
+  basic_yield_context(
+      const detail::weak_ptr<callee_type>& coro,
+      caller_type& ca, Handler& handler)
+    : coro_(coro),
+      ca_(ca),
+      handler_(handler),
+      ec_(0)
+  {
+  }
+
+  /// Construct a yield context from another yield context type.
+  /**
+   * Requires that OtherHandler be convertible to Handler.
+   */
+  template <typename OtherHandler>
+  basic_yield_context(const basic_yield_context<OtherHandler>& other)
+    : coro_(other.coro_),
+      ca_(other.ca_),
+      handler_(other.handler_),
+      ec_(other.ec_)
+  {
+  }
+
+  /// Return a yield context that sets the specified error_code.
+  /**
+   * By default, when a yield context is used with an asynchronous operation, a
+   * non-success error_code is converted to system_error and thrown. This
+   * operator may be used to specify an error_code object that should instead be
+   * set with the asynchronous operation's result. For example:
+   *
+   * @code template <typename Handler>
+   * void my_coroutine(basic_yield_context<Handler> yield)
+   * {
+   *   ...
+   *   std::size_t n = my_socket.async_read_some(buffer, yield[ec]);
+   *   if (ec)
+   *   {
+   *     // An error occurred.
+   *   }
+   *   ...
+   * } @endcode
+   */
+  basic_yield_context operator[](asio::error_code& ec) const
+  {
+    basic_yield_context tmp(*this);
+    tmp.ec_ = &ec;
+    return tmp;
+  }
+
+#if defined(GENERATING_DOCUMENTATION)
+private:
+#endif // defined(GENERATING_DOCUMENTATION)
+  detail::weak_ptr<callee_type> coro_;
+  caller_type& ca_;
+  Handler handler_;
+  asio::error_code* ec_;
+};
+
+#if defined(GENERATING_DOCUMENTATION)
+/// Context object that represents the currently executing coroutine.
+typedef basic_yield_context<unspecified> yield_context;
+#else // defined(GENERATING_DOCUMENTATION)
+typedef basic_yield_context<
+  executor_binder<void(*)(), executor> > yield_context;
+#endif // defined(GENERATING_DOCUMENTATION)
+
+/**
+ * @defgroup spawn asio::spawn
+ *
+ * @brief Start a new stackful coroutine.
+ *
+ * The spawn() function is a high-level wrapper over the Boost.Coroutine
+ * library. This function enables programs to implement asynchronous logic in a
+ * synchronous manner, as illustrated by the following example:
+ *
+ * @code asio::spawn(my_strand, do_echo);
+ *
+ * // ...
+ *
+ * void do_echo(asio::yield_context yield)
+ * {
+ *   try
+ *   {
+ *     char data[128];
+ *     for (;;)
+ *     {
+ *       std::size_t length =
+ *         my_socket.async_read_some(
+ *           asio::buffer(data), yield);
+ *
+ *       asio::async_write(my_socket,
+ *           asio::buffer(data, length), yield);
+ *     }
+ *   }
+ *   catch (std::exception& e)
+ *   {
+ *     // ...
+ *   }
+ * } @endcode
+ */
+/*@{*/
+
+/// Start a new stackful coroutine, calling the specified handler when it
+/// completes.
+/**
+ * This function is used to launch a new coroutine.
+ *
+ * @param function The coroutine function. The function must have the signature:
+ * @code void function(basic_yield_context<Handler> yield); @endcode
+ *
+ * @param attributes Boost.Coroutine attributes used to customise the coroutine.
+ */
+template <typename Function>
+void spawn(ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes
+      = boost::coroutines::attributes());
+
+/// Start a new stackful coroutine, calling the specified handler when it
+/// completes.
+/**
+ * This function is used to launch a new coroutine.
+ *
+ * @param handler A handler to be called when the coroutine exits. More
+ * importantly, the handler provides an execution context (via the the handler
+ * invocation hook) for the coroutine. The handler must have the signature:
+ * @code void handler(); @endcode
+ *
+ * @param function The coroutine function. The function must have the signature:
+ * @code void function(basic_yield_context<Handler> yield); @endcode
+ *
+ * @param attributes Boost.Coroutine attributes used to customise the coroutine.
+ */
+template <typename Handler, typename Function>
+void spawn(ASIO_MOVE_ARG(Handler) handler,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes
+      = boost::coroutines::attributes(),
+    typename enable_if<!is_executor<typename decay<Handler>::type>::value &&
+      !is_convertible<Handler&, execution_context&>::value>::type* = 0);
+
+/// Start a new stackful coroutine, inheriting the execution context of another.
+/**
+ * This function is used to launch a new coroutine.
+ *
+ * @param ctx Identifies the current coroutine as a parent of the new
+ * coroutine. This specifies that the new coroutine should inherit the
+ * execution context of the parent. For example, if the parent coroutine is
+ * executing in a particular strand, then the new coroutine will execute in the
+ * same strand.
+ *
+ * @param function The coroutine function. The function must have the signature:
+ * @code void function(basic_yield_context<Handler> yield); @endcode
+ *
+ * @param attributes Boost.Coroutine attributes used to customise the coroutine.
+ */
+template <typename Handler, typename Function>
+void spawn(basic_yield_context<Handler> ctx,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes
+      = boost::coroutines::attributes());
+
+/// Start a new stackful coroutine that executes on a given executor.
+/**
+ * This function is used to launch a new coroutine.
+ *
+ * @param ex Identifies the executor that will run the coroutine. The new
+ * coroutine is implicitly given its own strand within this executor.
+ *
+ * @param function The coroutine function. The function must have the signature:
+ * @code void function(yield_context yield); @endcode
+ *
+ * @param attributes Boost.Coroutine attributes used to customise the coroutine.
+ */
+template <typename Function, typename Executor>
+void spawn(const Executor& ex,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes
+      = boost::coroutines::attributes(),
+    typename enable_if<is_executor<Executor>::value>::type* = 0);
+
+/// Start a new stackful coroutine that executes on a given strand.
+/**
+ * This function is used to launch a new coroutine.
+ *
+ * @param ex Identifies the strand that will run the coroutine.
+ *
+ * @param function The coroutine function. The function must have the signature:
+ * @code void function(yield_context yield); @endcode
+ *
+ * @param attributes Boost.Coroutine attributes used to customise the coroutine.
+ */
+template <typename Function, typename Executor>
+void spawn(const strand<Executor>& ex,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes
+      = boost::coroutines::attributes());
+
+/// Start a new stackful coroutine that executes in the context of a strand.
+/**
+ * This function is used to launch a new coroutine.
+ *
+ * @param s Identifies a strand. By starting multiple coroutines on the same
+ * strand, the implementation ensures that none of those coroutines can execute
+ * simultaneously.
+ *
+ * @param function The coroutine function. The function must have the signature:
+ * @code void function(yield_context yield); @endcode
+ *
+ * @param attributes Boost.Coroutine attributes used to customise the coroutine.
+ */
+template <typename Function>
+void spawn(const asio::io_context::strand& s,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes
+      = boost::coroutines::attributes());
+
+/// Start a new stackful coroutine that executes on a given execution context.
+/**
+ * This function is used to launch a new coroutine.
+ *
+ * @param ctx Identifies the execution context that will run the coroutine. The
+ * new coroutine is implicitly given its own strand within this execution
+ * context.
+ *
+ * @param function The coroutine function. The function must have the signature:
+ * @code void function(yield_context yield); @endcode
+ *
+ * @param attributes Boost.Coroutine attributes used to customise the coroutine.
+ */
+template <typename Function, typename ExecutionContext>
+void spawn(ExecutionContext& ctx,
+    ASIO_MOVE_ARG(Function) function,
+    const boost::coroutines::attributes& attributes
+      = boost::coroutines::attributes(),
+    typename enable_if<is_convertible<
+      ExecutionContext&, execution_context&>::value>::type* = 0);
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/spawn.hpp"
+
+#endif // ASIO_SPAWN_HPP
diff --git a/subprojects/asio/include/asio/ssl.hpp b/subprojects/asio/include/asio/ssl.hpp
new file mode 100644
index 000000000..cbad19d81
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl.hpp
@@ -0,0 +1,27 @@
+//
+// ssl.hpp
+// ~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_HPP
+#define ASIO_SSL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/ssl/context.hpp"
+#include "asio/ssl/context_base.hpp"
+#include "asio/ssl/error.hpp"
+#include "asio/ssl/rfc2818_verification.hpp"
+#include "asio/ssl/stream.hpp"
+#include "asio/ssl/stream_base.hpp"
+#include "asio/ssl/verify_context.hpp"
+#include "asio/ssl/verify_mode.hpp"
+
+#endif // ASIO_SSL_HPP
diff --git a/subprojects/asio/include/asio/ssl/context.hpp b/subprojects/asio/include/asio/ssl/context.hpp
new file mode 100644
index 000000000..9543aab68
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/context.hpp
@@ -0,0 +1,758 @@
+//
+// ssl/context.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_CONTEXT_HPP
+#define ASIO_SSL_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <string>
+#include "asio/buffer.hpp"
+#include "asio/io_context.hpp"
+#include "asio/ssl/context_base.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+#include "asio/ssl/detail/openssl_init.hpp"
+#include "asio/ssl/detail/password_callback.hpp"
+#include "asio/ssl/detail/verify_callback.hpp"
+#include "asio/ssl/verify_mode.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+class context
+  : public context_base,
+    private noncopyable
+{
+public:
+  /// The native handle type of the SSL context.
+  typedef SSL_CTX* native_handle_type;
+
+  /// Constructor.
+  ASIO_DECL explicit context(method m);
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a context from another.
+  /**
+   * This constructor moves an SSL context from one object to another.
+   *
+   * @param other The other context object from which the move will occur.
+   *
+   * @note Following the move, the following operations only are valid for the
+   * moved-from object:
+   * @li Destruction.
+   * @li As a target for move-assignment.
+   */
+  ASIO_DECL context(context&& other);
+
+  /// Move-assign a context from another.
+  /**
+   * This assignment operator moves an SSL context from one object to another.
+   *
+   * @param other The other context object from which the move will occur.
+   *
+   * @note Following the move, the following operations only are valid for the
+   * moved-from object:
+   * @li Destruction.
+   * @li As a target for move-assignment.
+   */
+  ASIO_DECL context& operator=(context&& other);
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destructor.
+  ASIO_DECL ~context();
+
+  /// Get the underlying implementation in the native type.
+  /**
+   * This function may be used to obtain the underlying implementation of the
+   * context. This is intended to allow access to context functionality that is
+   * not otherwise provided.
+   */
+  ASIO_DECL native_handle_type native_handle();
+
+  /// Clear options on the context.
+  /**
+   * This function may be used to configure the SSL options used by the context.
+   *
+   * @param o A bitmask of options. The available option values are defined in
+   * the context_base class. The specified options, if currently enabled on the
+   * context, are cleared.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_clear_options.
+   */
+  ASIO_DECL void clear_options(options o);
+
+  /// Clear options on the context.
+  /**
+   * This function may be used to configure the SSL options used by the context.
+   *
+   * @param o A bitmask of options. The available option values are defined in
+   * the context_base class. The specified options, if currently enabled on the
+   * context, are cleared.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_clear_options.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID clear_options(options o,
+      asio::error_code& ec);
+
+  /// Set options on the context.
+  /**
+   * This function may be used to configure the SSL options used by the context.
+   *
+   * @param o A bitmask of options. The available option values are defined in
+   * the context_base class. The options are bitwise-ored with any existing
+   * value for the options.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_options.
+   */
+  ASIO_DECL void set_options(options o);
+
+  /// Set options on the context.
+  /**
+   * This function may be used to configure the SSL options used by the context.
+   *
+   * @param o A bitmask of options. The available option values are defined in
+   * the context_base class. The options are bitwise-ored with any existing
+   * value for the options.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_options.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID set_options(options o,
+      asio::error_code& ec);
+
+  /// Set the peer verification mode.
+  /**
+   * This function may be used to configure the peer verification mode used by
+   * the context.
+   *
+   * @param v A bitmask of peer verification modes. See @ref verify_mode for
+   * available values.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_verify.
+   */
+  ASIO_DECL void set_verify_mode(verify_mode v);
+
+  /// Set the peer verification mode.
+  /**
+   * This function may be used to configure the peer verification mode used by
+   * the context.
+   *
+   * @param v A bitmask of peer verification modes. See @ref verify_mode for
+   * available values.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_verify.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID set_verify_mode(
+      verify_mode v, asio::error_code& ec);
+
+  /// Set the peer verification depth.
+  /**
+   * This function may be used to configure the maximum verification depth
+   * allowed by the context.
+   *
+   * @param depth Maximum depth for the certificate chain verification that
+   * shall be allowed.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_verify_depth.
+   */
+  ASIO_DECL void set_verify_depth(int depth);
+
+  /// Set the peer verification depth.
+  /**
+   * This function may be used to configure the maximum verification depth
+   * allowed by the context.
+   *
+   * @param depth Maximum depth for the certificate chain verification that
+   * shall be allowed.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_verify_depth.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID set_verify_depth(
+      int depth, asio::error_code& ec);
+
+  /// Set the callback used to verify peer certificates.
+  /**
+   * This function is used to specify a callback function that will be called
+   * by the implementation when it needs to verify a peer certificate.
+   *
+   * @param callback The function object to be used for verifying a certificate.
+   * The function signature of the handler must be:
+   * @code bool verify_callback(
+   *   bool preverified, // True if the certificate passed pre-verification.
+   *   verify_context& ctx // The peer certificate and other context.
+   * ); @endcode
+   * The return value of the callback is true if the certificate has passed
+   * verification, false otherwise.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_verify.
+   */
+  template <typename VerifyCallback>
+  void set_verify_callback(VerifyCallback callback);
+
+  /// Set the callback used to verify peer certificates.
+  /**
+   * This function is used to specify a callback function that will be called
+   * by the implementation when it needs to verify a peer certificate.
+   *
+   * @param callback The function object to be used for verifying a certificate.
+   * The function signature of the handler must be:
+   * @code bool verify_callback(
+   *   bool preverified, // True if the certificate passed pre-verification.
+   *   verify_context& ctx // The peer certificate and other context.
+   * ); @endcode
+   * The return value of the callback is true if the certificate has passed
+   * verification, false otherwise.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_verify.
+   */
+  template <typename VerifyCallback>
+  ASIO_SYNC_OP_VOID set_verify_callback(VerifyCallback callback,
+      asio::error_code& ec);
+
+  /// Load a certification authority file for performing verification.
+  /**
+   * This function is used to load one or more trusted certification authorities
+   * from a file.
+   *
+   * @param filename The name of a file containing certification authority
+   * certificates in PEM format.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_load_verify_locations.
+   */
+  ASIO_DECL void load_verify_file(const std::string& filename);
+
+  /// Load a certification authority file for performing verification.
+  /**
+   * This function is used to load the certificates for one or more trusted
+   * certification authorities from a file.
+   *
+   * @param filename The name of a file containing certification authority
+   * certificates in PEM format.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_load_verify_locations.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID load_verify_file(
+      const std::string& filename, asio::error_code& ec);
+
+  /// Add certification authority for performing verification.
+  /**
+   * This function is used to add one trusted certification authority
+   * from a memory buffer.
+   *
+   * @param ca The buffer containing the certification authority certificate.
+   * The certificate must use the PEM format.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_get_cert_store and @c X509_STORE_add_cert.
+   */
+  ASIO_DECL void add_certificate_authority(const const_buffer& ca);
+
+  /// Add certification authority for performing verification.
+  /**
+   * This function is used to add one trusted certification authority
+   * from a memory buffer.
+   *
+   * @param ca The buffer containing the certification authority certificate.
+   * The certificate must use the PEM format.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_get_cert_store and @c X509_STORE_add_cert.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID add_certificate_authority(
+      const const_buffer& ca, asio::error_code& ec);
+
+  /// Configures the context to use the default directories for finding
+  /// certification authority certificates.
+  /**
+   * This function specifies that the context should use the default,
+   * system-dependent directories for locating certification authority
+   * certificates.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_default_verify_paths.
+   */
+  ASIO_DECL void set_default_verify_paths();
+
+  /// Configures the context to use the default directories for finding
+  /// certification authority certificates.
+  /**
+   * This function specifies that the context should use the default,
+   * system-dependent directories for locating certification authority
+   * certificates.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_default_verify_paths.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID set_default_verify_paths(
+      asio::error_code& ec);
+
+  /// Add a directory containing certificate authority files to be used for
+  /// performing verification.
+  /**
+   * This function is used to specify the name of a directory containing
+   * certification authority certificates. Each file in the directory must
+   * contain a single certificate. The files must be named using the subject
+   * name's hash and an extension of ".0".
+   *
+   * @param path The name of a directory containing the certificates.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_load_verify_locations.
+   */
+  ASIO_DECL void add_verify_path(const std::string& path);
+
+  /// Add a directory containing certificate authority files to be used for
+  /// performing verification.
+  /**
+   * This function is used to specify the name of a directory containing
+   * certification authority certificates. Each file in the directory must
+   * contain a single certificate. The files must be named using the subject
+   * name's hash and an extension of ".0".
+   *
+   * @param path The name of a directory containing the certificates.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_load_verify_locations.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID add_verify_path(
+      const std::string& path, asio::error_code& ec);
+
+  /// Use a certificate from a memory buffer.
+  /**
+   * This function is used to load a certificate into the context from a buffer.
+   *
+   * @param certificate The buffer containing the certificate.
+   *
+   * @param format The certificate format (ASN.1 or PEM).
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_certificate or SSL_CTX_use_certificate_ASN1.
+   */
+  ASIO_DECL void use_certificate(
+      const const_buffer& certificate, file_format format);
+
+  /// Use a certificate from a memory buffer.
+  /**
+   * This function is used to load a certificate into the context from a buffer.
+   *
+   * @param certificate The buffer containing the certificate.
+   *
+   * @param format The certificate format (ASN.1 or PEM).
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_certificate or SSL_CTX_use_certificate_ASN1.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_certificate(
+      const const_buffer& certificate, file_format format,
+      asio::error_code& ec);
+
+  /// Use a certificate from a file.
+  /**
+   * This function is used to load a certificate into the context from a file.
+   *
+   * @param filename The name of the file containing the certificate.
+   *
+   * @param format The file format (ASN.1 or PEM).
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_certificate_file.
+   */
+  ASIO_DECL void use_certificate_file(
+      const std::string& filename, file_format format);
+
+  /// Use a certificate from a file.
+  /**
+   * This function is used to load a certificate into the context from a file.
+   *
+   * @param filename The name of the file containing the certificate.
+   *
+   * @param format The file format (ASN.1 or PEM).
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_certificate_file.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_certificate_file(
+      const std::string& filename, file_format format,
+      asio::error_code& ec);
+
+  /// Use a certificate chain from a memory buffer.
+  /**
+   * This function is used to load a certificate chain into the context from a
+   * buffer.
+   *
+   * @param chain The buffer containing the certificate chain. The certificate
+   * chain must use the PEM format.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_certificate and SSL_CTX_add_extra_chain_cert.
+   */
+  ASIO_DECL void use_certificate_chain(const const_buffer& chain);
+
+  /// Use a certificate chain from a memory buffer.
+  /**
+   * This function is used to load a certificate chain into the context from a
+   * buffer.
+   *
+   * @param chain The buffer containing the certificate chain. The certificate
+   * chain must use the PEM format.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_certificate and SSL_CTX_add_extra_chain_cert.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_certificate_chain(
+      const const_buffer& chain, asio::error_code& ec);
+
+  /// Use a certificate chain from a file.
+  /**
+   * This function is used to load a certificate chain into the context from a
+   * file.
+   *
+   * @param filename The name of the file containing the certificate. The file
+   * must use the PEM format.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_certificate_chain_file.
+   */
+  ASIO_DECL void use_certificate_chain_file(const std::string& filename);
+
+  /// Use a certificate chain from a file.
+  /**
+   * This function is used to load a certificate chain into the context from a
+   * file.
+   *
+   * @param filename The name of the file containing the certificate. The file
+   * must use the PEM format.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_certificate_chain_file.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_certificate_chain_file(
+      const std::string& filename, asio::error_code& ec);
+
+  /// Use a private key from a memory buffer.
+  /**
+   * This function is used to load a private key into the context from a buffer.
+   *
+   * @param private_key The buffer containing the private key.
+   *
+   * @param format The private key format (ASN.1 or PEM).
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_PrivateKey or SSL_CTX_use_PrivateKey_ASN1.
+   */
+  ASIO_DECL void use_private_key(
+      const const_buffer& private_key, file_format format);
+
+  /// Use a private key from a memory buffer.
+  /**
+   * This function is used to load a private key into the context from a buffer.
+   *
+   * @param private_key The buffer containing the private key.
+   *
+   * @param format The private key format (ASN.1 or PEM).
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_PrivateKey or SSL_CTX_use_PrivateKey_ASN1.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_private_key(
+      const const_buffer& private_key, file_format format,
+      asio::error_code& ec);
+
+  /// Use a private key from a file.
+  /**
+   * This function is used to load a private key into the context from a file.
+   *
+   * @param filename The name of the file containing the private key.
+   *
+   * @param format The file format (ASN.1 or PEM).
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_PrivateKey_file.
+   */
+  ASIO_DECL void use_private_key_file(
+      const std::string& filename, file_format format);
+
+  /// Use a private key from a file.
+  /**
+   * This function is used to load a private key into the context from a file.
+   *
+   * @param filename The name of the file containing the private key.
+   *
+   * @param format The file format (ASN.1 or PEM).
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_PrivateKey_file.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_private_key_file(
+      const std::string& filename, file_format format,
+      asio::error_code& ec);
+
+  /// Use an RSA private key from a memory buffer.
+  /**
+   * This function is used to load an RSA private key into the context from a
+   * buffer.
+   *
+   * @param private_key The buffer containing the RSA private key.
+   *
+   * @param format The private key format (ASN.1 or PEM).
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_RSAPrivateKey or SSL_CTX_use_RSAPrivateKey_ASN1.
+   */
+  ASIO_DECL void use_rsa_private_key(
+      const const_buffer& private_key, file_format format);
+
+  /// Use an RSA private key from a memory buffer.
+  /**
+   * This function is used to load an RSA private key into the context from a
+   * buffer.
+   *
+   * @param private_key The buffer containing the RSA private key.
+   *
+   * @param format The private key format (ASN.1 or PEM).
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_RSAPrivateKey or SSL_CTX_use_RSAPrivateKey_ASN1.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_rsa_private_key(
+      const const_buffer& private_key, file_format format,
+      asio::error_code& ec);
+
+  /// Use an RSA private key from a file.
+  /**
+   * This function is used to load an RSA private key into the context from a
+   * file.
+   *
+   * @param filename The name of the file containing the RSA private key.
+   *
+   * @param format The file format (ASN.1 or PEM).
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_use_RSAPrivateKey_file.
+   */
+  ASIO_DECL void use_rsa_private_key_file(
+      const std::string& filename, file_format format);
+
+  /// Use an RSA private key from a file.
+  /**
+   * This function is used to load an RSA private key into the context from a
+   * file.
+   *
+   * @param filename The name of the file containing the RSA private key.
+   *
+   * @param format The file format (ASN.1 or PEM).
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_use_RSAPrivateKey_file.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_rsa_private_key_file(
+      const std::string& filename, file_format format,
+      asio::error_code& ec);
+
+  /// Use the specified memory buffer to obtain the temporary Diffie-Hellman
+  /// parameters.
+  /**
+   * This function is used to load Diffie-Hellman parameters into the context
+   * from a buffer.
+   *
+   * @param dh The memory buffer containing the Diffie-Hellman parameters. The
+   * buffer must use the PEM format.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_tmp_dh.
+   */
+  ASIO_DECL void use_tmp_dh(const const_buffer& dh);
+
+  /// Use the specified memory buffer to obtain the temporary Diffie-Hellman
+  /// parameters.
+  /**
+   * This function is used to load Diffie-Hellman parameters into the context
+   * from a buffer.
+   *
+   * @param dh The memory buffer containing the Diffie-Hellman parameters. The
+   * buffer must use the PEM format.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_tmp_dh.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_tmp_dh(
+      const const_buffer& dh, asio::error_code& ec);
+
+  /// Use the specified file to obtain the temporary Diffie-Hellman parameters.
+  /**
+   * This function is used to load Diffie-Hellman parameters into the context
+   * from a file.
+   *
+   * @param filename The name of the file containing the Diffie-Hellman
+   * parameters. The file must use the PEM format.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_tmp_dh.
+   */
+  ASIO_DECL void use_tmp_dh_file(const std::string& filename);
+
+  /// Use the specified file to obtain the temporary Diffie-Hellman parameters.
+  /**
+   * This function is used to load Diffie-Hellman parameters into the context
+   * from a file.
+   *
+   * @param filename The name of the file containing the Diffie-Hellman
+   * parameters. The file must use the PEM format.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_tmp_dh.
+   */
+  ASIO_DECL ASIO_SYNC_OP_VOID use_tmp_dh_file(
+      const std::string& filename, asio::error_code& ec);
+
+  /// Set the password callback.
+  /**
+   * This function is used to specify a callback function to obtain password
+   * information about an encrypted key in PEM format.
+   *
+   * @param callback The function object to be used for obtaining the password.
+   * The function signature of the handler must be:
+   * @code std::string password_callback(
+   *   std::size_t max_length,  // The maximum size for a password.
+   *   password_purpose purpose // Whether password is for reading or writing.
+   * ); @endcode
+   * The return value of the callback is a string containing the password.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_CTX_set_default_passwd_cb.
+   */
+  template <typename PasswordCallback>
+  void set_password_callback(PasswordCallback callback);
+
+  /// Set the password callback.
+  /**
+   * This function is used to specify a callback function to obtain password
+   * information about an encrypted key in PEM format.
+   *
+   * @param callback The function object to be used for obtaining the password.
+   * The function signature of the handler must be:
+   * @code std::string password_callback(
+   *   std::size_t max_length,  // The maximum size for a password.
+   *   password_purpose purpose // Whether password is for reading or writing.
+   * ); @endcode
+   * The return value of the callback is a string containing the password.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_CTX_set_default_passwd_cb.
+   */
+  template <typename PasswordCallback>
+  ASIO_SYNC_OP_VOID set_password_callback(PasswordCallback callback,
+      asio::error_code& ec);
+
+private:
+  struct bio_cleanup;
+  struct x509_cleanup;
+  struct evp_pkey_cleanup;
+  struct rsa_cleanup;
+  struct dh_cleanup;
+
+  // Helper function used to set a peer certificate verification callback.
+  ASIO_DECL ASIO_SYNC_OP_VOID do_set_verify_callback(
+      detail::verify_callback_base* callback, asio::error_code& ec);
+
+  // Callback used when the SSL implementation wants to verify a certificate.
+  ASIO_DECL static int verify_callback_function(
+      int preverified, X509_STORE_CTX* ctx);
+
+  // Helper function used to set a password callback.
+  ASIO_DECL ASIO_SYNC_OP_VOID do_set_password_callback(
+      detail::password_callback_base* callback, asio::error_code& ec);
+
+  // Callback used when the SSL implementation wants a password.
+  ASIO_DECL static int password_callback_function(
+      char* buf, int size, int purpose, void* data);
+
+  // Helper function to set the temporary Diffie-Hellman parameters from a BIO.
+  ASIO_DECL ASIO_SYNC_OP_VOID do_use_tmp_dh(
+      BIO* bio, asio::error_code& ec);
+
+  // Helper function to make a BIO from a memory buffer.
+  ASIO_DECL BIO* make_buffer_bio(const const_buffer& b);
+
+  // The underlying native implementation.
+  native_handle_type handle_;
+
+  // Ensure openssl is initialised.
+  asio::ssl::detail::openssl_init<> init_;
+};
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/ssl/impl/context.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ssl/impl/context.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_SSL_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/ssl/context_base.hpp b/subprojects/asio/include/asio/ssl/context_base.hpp
new file mode 100644
index 000000000..b862f9682
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/context_base.hpp
@@ -0,0 +1,209 @@
+//
+// ssl/context_base.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_CONTEXT_BASE_HPP
+#define ASIO_SSL_CONTEXT_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+/// The context_base class is used as a base for the basic_context class
+/// template so that we have a common place to define various enums.
+class context_base
+{
+public:
+  /// Different methods supported by a context.
+  enum method
+  {
+    /// Generic SSL version 2.
+    sslv2,
+
+    /// SSL version 2 client.
+    sslv2_client,
+
+    /// SSL version 2 server.
+    sslv2_server,
+
+    /// Generic SSL version 3.
+    sslv3,
+
+    /// SSL version 3 client.
+    sslv3_client,
+
+    /// SSL version 3 server.
+    sslv3_server,
+
+    /// Generic TLS version 1.
+    tlsv1,
+
+    /// TLS version 1 client.
+    tlsv1_client,
+
+    /// TLS version 1 server.
+    tlsv1_server,
+
+    /// Generic SSL/TLS.
+    sslv23,
+
+    /// SSL/TLS client.
+    sslv23_client,
+
+    /// SSL/TLS server.
+    sslv23_server,
+
+    /// Generic TLS version 1.1.
+    tlsv11,
+
+    /// TLS version 1.1 client.
+    tlsv11_client,
+
+    /// TLS version 1.1 server.
+    tlsv11_server,
+
+    /// Generic TLS version 1.2.
+    tlsv12,
+
+    /// TLS version 1.2 client.
+    tlsv12_client,
+
+    /// TLS version 1.2 server.
+    tlsv12_server,
+
+    /// Generic TLS version 1.3.
+    tlsv13,
+
+    /// TLS version 1.3 client.
+    tlsv13_client,
+
+    /// TLS version 1.3 server.
+    tlsv13_server,
+
+    /// Generic TLS.
+    tls,
+
+    /// TLS client.
+    tls_client,
+
+    /// TLS server.
+    tls_server
+  };
+
+  /// Bitmask type for SSL options.
+  typedef long options;
+
+#if defined(GENERATING_DOCUMENTATION)
+  /// Implement various bug workarounds.
+  static const long default_workarounds = implementation_defined;
+
+  /// Always create a new key when using tmp_dh parameters.
+  static const long single_dh_use = implementation_defined;
+
+  /// Disable SSL v2.
+  static const long no_sslv2 = implementation_defined;
+
+  /// Disable SSL v3.
+  static const long no_sslv3 = implementation_defined;
+
+  /// Disable TLS v1.
+  static const long no_tlsv1 = implementation_defined;
+
+  /// Disable TLS v1.1.
+  static const long no_tlsv1_1 = implementation_defined;
+
+  /// Disable TLS v1.2.
+  static const long no_tlsv1_2 = implementation_defined;
+
+  /// Disable TLS v1.3.
+  static const long no_tlsv1_3 = implementation_defined;
+
+  /// Disable compression. Compression is disabled by default.
+  static const long no_compression = implementation_defined;
+#else
+  ASIO_STATIC_CONSTANT(long, default_workarounds = SSL_OP_ALL);
+  ASIO_STATIC_CONSTANT(long, single_dh_use = SSL_OP_SINGLE_DH_USE);
+  ASIO_STATIC_CONSTANT(long, no_sslv2 = SSL_OP_NO_SSLv2);
+  ASIO_STATIC_CONSTANT(long, no_sslv3 = SSL_OP_NO_SSLv3);
+  ASIO_STATIC_CONSTANT(long, no_tlsv1 = SSL_OP_NO_TLSv1);
+# if defined(SSL_OP_NO_TLSv1_1)
+  ASIO_STATIC_CONSTANT(long, no_tlsv1_1 = SSL_OP_NO_TLSv1_1);
+# else // defined(SSL_OP_NO_TLSv1_1)
+  ASIO_STATIC_CONSTANT(long, no_tlsv1_1 = 0x10000000L);
+# endif // defined(SSL_OP_NO_TLSv1_1)
+# if defined(SSL_OP_NO_TLSv1_2)
+  ASIO_STATIC_CONSTANT(long, no_tlsv1_2 = SSL_OP_NO_TLSv1_2);
+# else // defined(SSL_OP_NO_TLSv1_2)
+  ASIO_STATIC_CONSTANT(long, no_tlsv1_2 = 0x08000000L);
+# endif // defined(SSL_OP_NO_TLSv1_2)
+# if defined(SSL_OP_NO_TLSv1_3)
+  ASIO_STATIC_CONSTANT(long, no_tlsv1_3 = SSL_OP_NO_TLSv1_3);
+# else // defined(SSL_OP_NO_TLSv1_3)
+  ASIO_STATIC_CONSTANT(long, no_tlsv1_3 = 0x20000000L);
+# endif // defined(SSL_OP_NO_TLSv1_3)
+# if defined(SSL_OP_NO_COMPRESSION)
+  ASIO_STATIC_CONSTANT(long, no_compression = SSL_OP_NO_COMPRESSION);
+# else // defined(SSL_OP_NO_COMPRESSION)
+  ASIO_STATIC_CONSTANT(long, no_compression = 0x20000L);
+# endif // defined(SSL_OP_NO_COMPRESSION)
+#endif
+
+  /// File format types.
+  enum file_format
+  {
+    /// ASN.1 file.
+    asn1,
+
+    /// PEM file.
+    pem
+  };
+
+#if !defined(GENERATING_DOCUMENTATION)
+  // The following types and constants are preserved for backward compatibility.
+  // New programs should use the equivalents of the same names that are defined
+  // in the asio::ssl namespace.
+  typedef int verify_mode;
+  ASIO_STATIC_CONSTANT(int, verify_none = SSL_VERIFY_NONE);
+  ASIO_STATIC_CONSTANT(int, verify_peer = SSL_VERIFY_PEER);
+  ASIO_STATIC_CONSTANT(int,
+      verify_fail_if_no_peer_cert = SSL_VERIFY_FAIL_IF_NO_PEER_CERT);
+  ASIO_STATIC_CONSTANT(int, verify_client_once = SSL_VERIFY_CLIENT_ONCE);
+#endif
+
+  /// Purpose of PEM password.
+  enum password_purpose
+  {
+    /// The password is needed for reading/decryption.
+    for_reading,
+
+    /// The password is needed for writing/encryption.
+    for_writing
+  };
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~context_base()
+  {
+  }
+};
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_CONTEXT_BASE_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/buffered_handshake_op.hpp b/subprojects/asio/include/asio/ssl/detail/buffered_handshake_op.hpp
new file mode 100644
index 000000000..38a03fcce
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/buffered_handshake_op.hpp
@@ -0,0 +1,114 @@
+//
+// ssl/detail/buffered_handshake_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_BUFFERED_HANDSHAKE_OP_HPP
+#define ASIO_SSL_DETAIL_BUFFERED_HANDSHAKE_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/ssl/detail/engine.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+template <typename ConstBufferSequence>
+class buffered_handshake_op
+{
+public:
+  buffered_handshake_op(stream_base::handshake_type type,
+      const ConstBufferSequence& buffers)
+    : type_(type),
+      buffers_(buffers),
+      total_buffer_size_(asio::buffer_size(buffers_))
+  {
+  }
+
+  engine::want operator()(engine& eng,
+      asio::error_code& ec,
+      std::size_t& bytes_transferred) const
+  {
+    return this->process(eng, ec, bytes_transferred,
+        asio::buffer_sequence_begin(buffers_),
+        asio::buffer_sequence_end(buffers_));
+  }
+
+  template <typename Handler>
+  void call_handler(Handler& handler,
+      const asio::error_code& ec,
+      const std::size_t& bytes_transferred) const
+  {
+    handler(ec, bytes_transferred);
+  }
+
+private:
+  template <typename Iterator>
+  engine::want process(engine& eng,
+      asio::error_code& ec,
+      std::size_t& bytes_transferred,
+      Iterator begin, Iterator end) const
+  {
+    Iterator iter = begin;
+    std::size_t accumulated_size = 0;
+
+    for (;;)
+    {
+      engine::want want = eng.handshake(type_, ec);
+      if (want != engine::want_input_and_retry
+          || bytes_transferred == total_buffer_size_)
+        return want;
+
+      // Find the next buffer piece to be fed to the engine.
+      while (iter != end)
+      {
+        const_buffer buffer(*iter);
+
+        // Skip over any buffers which have already been consumed by the engine.
+        if (bytes_transferred >= accumulated_size + buffer.size())
+        {
+          accumulated_size += buffer.size();
+          ++iter;
+          continue;
+        }
+
+        // The current buffer may have been partially consumed by the engine on
+        // a previous iteration. If so, adjust the buffer to point to the
+        // unused portion.
+        if (bytes_transferred > accumulated_size)
+          buffer = buffer + (bytes_transferred - accumulated_size);
+
+        // Pass the buffer to the engine, and update the bytes transferred to
+        // reflect the total number of bytes consumed so far.
+        bytes_transferred += buffer.size();
+        buffer = eng.put_input(buffer);
+        bytes_transferred -= buffer.size();
+        break;
+      }
+    }
+  }
+
+  stream_base::handshake_type type_;
+  ConstBufferSequence buffers_;
+  std::size_t total_buffer_size_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_BUFFERED_HANDSHAKE_OP_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/engine.hpp b/subprojects/asio/include/asio/ssl/detail/engine.hpp
new file mode 100644
index 000000000..2f033d66c
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/engine.hpp
@@ -0,0 +1,160 @@
+//
+// ssl/detail/engine.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_ENGINE_HPP
+#define ASIO_SSL_DETAIL_ENGINE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/buffer.hpp"
+#include "asio/detail/static_mutex.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+#include "asio/ssl/detail/verify_callback.hpp"
+#include "asio/ssl/stream_base.hpp"
+#include "asio/ssl/verify_mode.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+class engine
+{
+public:
+  enum want
+  {
+    // Returned by functions to indicate that the engine wants input. The input
+    // buffer should be updated to point to the data. The engine then needs to
+    // be called again to retry the operation.
+    want_input_and_retry = -2,
+
+    // Returned by functions to indicate that the engine wants to write output.
+    // The output buffer points to the data to be written. The engine then
+    // needs to be called again to retry the operation.
+    want_output_and_retry = -1,
+
+    // Returned by functions to indicate that the engine doesn't need input or
+    // output.
+    want_nothing = 0,
+
+    // Returned by functions to indicate that the engine wants to write output.
+    // The output buffer points to the data to be written. After that the
+    // operation is complete, and the engine does not need to be called again.
+    want_output = 1
+  };
+
+  // Construct a new engine for the specified context.
+  ASIO_DECL explicit engine(SSL_CTX* context);
+
+  // Destructor.
+  ASIO_DECL ~engine();
+
+  // Get the underlying implementation in the native type.
+  ASIO_DECL SSL* native_handle();
+
+  // Set the peer verification mode.
+  ASIO_DECL asio::error_code set_verify_mode(
+      verify_mode v, asio::error_code& ec);
+
+  // Set the peer verification depth.
+  ASIO_DECL asio::error_code set_verify_depth(
+      int depth, asio::error_code& ec);
+
+  // Set a peer certificate verification callback.
+  ASIO_DECL asio::error_code set_verify_callback(
+      verify_callback_base* callback, asio::error_code& ec);
+
+  // Perform an SSL handshake using either SSL_connect (client-side) or
+  // SSL_accept (server-side).
+  ASIO_DECL want handshake(
+      stream_base::handshake_type type, asio::error_code& ec);
+
+  // Perform a graceful shutdown of the SSL session.
+  ASIO_DECL want shutdown(asio::error_code& ec);
+
+  // Write bytes to the SSL session.
+  ASIO_DECL want write(const asio::const_buffer& data,
+      asio::error_code& ec, std::size_t& bytes_transferred);
+
+  // Read bytes from the SSL session.
+  ASIO_DECL want read(const asio::mutable_buffer& data,
+      asio::error_code& ec, std::size_t& bytes_transferred);
+
+  // Get output data to be written to the transport.
+  ASIO_DECL asio::mutable_buffer get_output(
+      const asio::mutable_buffer& data);
+
+  // Put input data that was read from the transport.
+  ASIO_DECL asio::const_buffer put_input(
+      const asio::const_buffer& data);
+
+  // Map an error::eof code returned by the underlying transport according to
+  // the type and state of the SSL session. Returns a const reference to the
+  // error code object, suitable for passing to a completion handler.
+  ASIO_DECL const asio::error_code& map_error_code(
+      asio::error_code& ec) const;
+
+private:
+  // Disallow copying and assignment.
+  engine(const engine&);
+  engine& operator=(const engine&);
+
+  // Callback used when the SSL implementation wants to verify a certificate.
+  ASIO_DECL static int verify_callback_function(
+      int preverified, X509_STORE_CTX* ctx);
+
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+  // The SSL_accept function may not be thread safe. This mutex is used to
+  // protect all calls to the SSL_accept function.
+  ASIO_DECL static asio::detail::static_mutex& accept_mutex();
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+
+  // Perform one operation. Returns >= 0 on success or error, want_read if the
+  // operation needs more input, or want_write if it needs to write some output
+  // before the operation can complete.
+  ASIO_DECL want perform(int (engine::* op)(void*, std::size_t),
+      void* data, std::size_t length, asio::error_code& ec,
+      std::size_t* bytes_transferred);
+
+  // Adapt the SSL_accept function to the signature needed for perform().
+  ASIO_DECL int do_accept(void*, std::size_t);
+
+  // Adapt the SSL_connect function to the signature needed for perform().
+  ASIO_DECL int do_connect(void*, std::size_t);
+
+  // Adapt the SSL_shutdown function to the signature needed for perform().
+  ASIO_DECL int do_shutdown(void*, std::size_t);
+
+  // Adapt the SSL_read function to the signature needed for perform().
+  ASIO_DECL int do_read(void* data, std::size_t length);
+
+  // Adapt the SSL_write function to the signature needed for perform().
+  ASIO_DECL int do_write(void* data, std::size_t length);
+
+  SSL* ssl_;
+  BIO* ext_bio_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ssl/detail/impl/engine.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_SSL_DETAIL_ENGINE_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/handshake_op.hpp b/subprojects/asio/include/asio/ssl/detail/handshake_op.hpp
new file mode 100644
index 000000000..f782023a1
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/handshake_op.hpp
@@ -0,0 +1,62 @@
+//
+// ssl/detail/handshake_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_HANDSHAKE_OP_HPP
+#define ASIO_SSL_DETAIL_HANDSHAKE_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/ssl/detail/engine.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+class handshake_op
+{
+public:
+  handshake_op(stream_base::handshake_type type)
+    : type_(type)
+  {
+  }
+
+  engine::want operator()(engine& eng,
+      asio::error_code& ec,
+      std::size_t& bytes_transferred) const
+  {
+    bytes_transferred = 0;
+    return eng.handshake(type_, ec);
+  }
+
+  template <typename Handler>
+  void call_handler(Handler& handler,
+      const asio::error_code& ec,
+      const std::size_t&) const
+  {
+    handler(ec);
+  }
+
+private:
+  stream_base::handshake_type type_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_HANDSHAKE_OP_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/impl/engine.ipp b/subprojects/asio/include/asio/ssl/detail/impl/engine.ipp
new file mode 100644
index 000000000..e60e8d6f8
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/impl/engine.ipp
@@ -0,0 +1,322 @@
+//
+// ssl/detail/impl/engine.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_IMPL_ENGINE_IPP
+#define ASIO_SSL_DETAIL_IMPL_ENGINE_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/ssl/detail/engine.hpp"
+#include "asio/ssl/error.hpp"
+#include "asio/ssl/verify_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+engine::engine(SSL_CTX* context)
+  : ssl_(::SSL_new(context))
+{
+  if (!ssl_)
+  {
+    asio::error_code ec(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    asio::detail::throw_error(ec, "engine");
+  }
+
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+  accept_mutex().init();
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+
+  ::SSL_set_mode(ssl_, SSL_MODE_ENABLE_PARTIAL_WRITE);
+  ::SSL_set_mode(ssl_, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
+#if defined(SSL_MODE_RELEASE_BUFFERS)
+  ::SSL_set_mode(ssl_, SSL_MODE_RELEASE_BUFFERS);
+#endif // defined(SSL_MODE_RELEASE_BUFFERS)
+
+  ::BIO* int_bio = 0;
+  ::BIO_new_bio_pair(&int_bio, 0, &ext_bio_, 0);
+  ::SSL_set_bio(ssl_, int_bio, int_bio);
+}
+
+engine::~engine()
+{
+  if (SSL_get_app_data(ssl_))
+  {
+    delete static_cast<verify_callback_base*>(SSL_get_app_data(ssl_));
+    SSL_set_app_data(ssl_, 0);
+  }
+
+  ::BIO_free(ext_bio_);
+  ::SSL_free(ssl_);
+}
+
+SSL* engine::native_handle()
+{
+  return ssl_;
+}
+
+asio::error_code engine::set_verify_mode(
+    verify_mode v, asio::error_code& ec)
+{
+  ::SSL_set_verify(ssl_, v, ::SSL_get_verify_callback(ssl_));
+
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code engine::set_verify_depth(
+    int depth, asio::error_code& ec)
+{
+  ::SSL_set_verify_depth(ssl_, depth);
+
+  ec = asio::error_code();
+  return ec;
+}
+
+asio::error_code engine::set_verify_callback(
+    verify_callback_base* callback, asio::error_code& ec)
+{
+  if (SSL_get_app_data(ssl_))
+    delete static_cast<verify_callback_base*>(SSL_get_app_data(ssl_));
+
+  SSL_set_app_data(ssl_, callback);
+
+  ::SSL_set_verify(ssl_, ::SSL_get_verify_mode(ssl_),
+      &engine::verify_callback_function);
+
+  ec = asio::error_code();
+  return ec;
+}
+
+int engine::verify_callback_function(int preverified, X509_STORE_CTX* ctx)
+{
+  if (ctx)
+  {
+    if (SSL* ssl = static_cast<SSL*>(
+          ::X509_STORE_CTX_get_ex_data(
+            ctx, ::SSL_get_ex_data_X509_STORE_CTX_idx())))
+    {
+      if (SSL_get_app_data(ssl))
+      {
+        verify_callback_base* callback =
+          static_cast<verify_callback_base*>(
+              SSL_get_app_data(ssl));
+
+        verify_context verify_ctx(ctx);
+        return callback->call(preverified != 0, verify_ctx) ? 1 : 0;
+      }
+    }
+  }
+
+  return 0;
+}
+
+engine::want engine::handshake(
+    stream_base::handshake_type type, asio::error_code& ec)
+{
+  return perform((type == asio::ssl::stream_base::client)
+      ? &engine::do_connect : &engine::do_accept, 0, 0, ec, 0);
+}
+
+engine::want engine::shutdown(asio::error_code& ec)
+{
+  return perform(&engine::do_shutdown, 0, 0, ec, 0);
+}
+
+engine::want engine::write(const asio::const_buffer& data,
+    asio::error_code& ec, std::size_t& bytes_transferred)
+{
+  if (data.size() == 0)
+  {
+    ec = asio::error_code();
+    return engine::want_nothing;
+  }
+
+  return perform(&engine::do_write,
+      const_cast<void*>(data.data()),
+      data.size(), ec, &bytes_transferred);
+}
+
+engine::want engine::read(const asio::mutable_buffer& data,
+    asio::error_code& ec, std::size_t& bytes_transferred)
+{
+  if (data.size() == 0)
+  {
+    ec = asio::error_code();
+    return engine::want_nothing;
+  }
+
+  return perform(&engine::do_read, data.data(),
+      data.size(), ec, &bytes_transferred);
+}
+
+asio::mutable_buffer engine::get_output(
+    const asio::mutable_buffer& data)
+{
+  int length = ::BIO_read(ext_bio_,
+      data.data(), static_cast<int>(data.size()));
+
+  return asio::buffer(data,
+      length > 0 ? static_cast<std::size_t>(length) : 0);
+}
+
+asio::const_buffer engine::put_input(
+    const asio::const_buffer& data)
+{
+  int length = ::BIO_write(ext_bio_,
+      data.data(), static_cast<int>(data.size()));
+
+  return asio::buffer(data +
+      (length > 0 ? static_cast<std::size_t>(length) : 0));
+}
+
+const asio::error_code& engine::map_error_code(
+    asio::error_code& ec) const
+{
+  // We only want to map the error::eof code.
+  if (ec != asio::error::eof)
+    return ec;
+
+  // If there's data yet to be read, it's an error.
+  if (BIO_wpending(ext_bio_))
+  {
+    ec = asio::ssl::error::stream_truncated;
+    return ec;
+  }
+
+  // SSL v2 doesn't provide a protocol-level shutdown, so an eof on the
+  // underlying transport is passed through.
+#if (OPENSSL_VERSION_NUMBER < 0x10100000L)
+  if (SSL_version(ssl_) == SSL2_VERSION)
+    return ec;
+#endif // (OPENSSL_VERSION_NUMBER < 0x10100000L)
+
+  // Otherwise, the peer should have negotiated a proper shutdown.
+  if ((::SSL_get_shutdown(ssl_) & SSL_RECEIVED_SHUTDOWN) == 0)
+  {
+    ec = asio::ssl::error::stream_truncated;
+  }
+
+  return ec;
+}
+
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+asio::detail::static_mutex& engine::accept_mutex()
+{
+  static asio::detail::static_mutex mutex = ASIO_STATIC_MUTEX_INIT;
+  return mutex;
+}
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+
+engine::want engine::perform(int (engine::* op)(void*, std::size_t),
+    void* data, std::size_t length, asio::error_code& ec,
+    std::size_t* bytes_transferred)
+{
+  std::size_t pending_output_before = ::BIO_ctrl_pending(ext_bio_);
+  ::ERR_clear_error();
+  int result = (this->*op)(data, length);
+  int ssl_error = ::SSL_get_error(ssl_, result);
+  int sys_error = static_cast<int>(::ERR_get_error());
+  std::size_t pending_output_after = ::BIO_ctrl_pending(ext_bio_);
+
+  if (ssl_error == SSL_ERROR_SSL)
+  {
+    ec = asio::error_code(sys_error,
+        asio::error::get_ssl_category());
+    return want_nothing;
+  }
+
+  if (ssl_error == SSL_ERROR_SYSCALL)
+  {
+    ec = asio::error_code(sys_error,
+        asio::error::get_system_category());
+    return want_nothing;
+  }
+
+  if (result > 0 && bytes_transferred)
+    *bytes_transferred = static_cast<std::size_t>(result);
+
+  if (ssl_error == SSL_ERROR_WANT_WRITE)
+  {
+    ec = asio::error_code();
+    return want_output_and_retry;
+  }
+  else if (pending_output_after > pending_output_before)
+  {
+    ec = asio::error_code();
+    return result > 0 ? want_output : want_output_and_retry;
+  }
+  else if (ssl_error == SSL_ERROR_WANT_READ)
+  {
+    ec = asio::error_code();
+    return want_input_and_retry;
+  }
+  else if (::SSL_get_shutdown(ssl_) & SSL_RECEIVED_SHUTDOWN)
+  {
+    ec = asio::error::eof;
+    return want_nothing;
+  }
+  else
+  {
+    ec = asio::error_code();
+    return want_nothing;
+  }
+}
+
+int engine::do_accept(void*, std::size_t)
+{
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+  asio::detail::static_mutex::scoped_lock lock(accept_mutex());
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+  return ::SSL_accept(ssl_);
+}
+
+int engine::do_connect(void*, std::size_t)
+{
+  return ::SSL_connect(ssl_);
+}
+
+int engine::do_shutdown(void*, std::size_t)
+{
+  int result = ::SSL_shutdown(ssl_);
+  if (result == 0)
+    result = ::SSL_shutdown(ssl_);
+  return result;
+}
+
+int engine::do_read(void* data, std::size_t length)
+{
+  return ::SSL_read(ssl_, data,
+      length < INT_MAX ? static_cast<int>(length) : INT_MAX);
+}
+
+int engine::do_write(void* data, std::size_t length)
+{
+  return ::SSL_write(ssl_, data,
+      length < INT_MAX ? static_cast<int>(length) : INT_MAX);
+}
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_IMPL_ENGINE_IPP
diff --git a/subprojects/asio/include/asio/ssl/detail/impl/openssl_init.ipp b/subprojects/asio/include/asio/ssl/detail/impl/openssl_init.ipp
new file mode 100644
index 000000000..fb0fff949
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/impl/openssl_init.ipp
@@ -0,0 +1,165 @@
+//
+// ssl/detail/impl/openssl_init.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2005 Voipster / Indrek dot Juhani at voipster dot com
+// Copyright (c) 2005-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_IMPL_OPENSSL_INIT_IPP
+#define ASIO_SSL_DETAIL_IMPL_OPENSSL_INIT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <vector>
+#include "asio/detail/assert.hpp"
+#include "asio/detail/mutex.hpp"
+#include "asio/detail/tss_ptr.hpp"
+#include "asio/ssl/detail/openssl_init.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+class openssl_init_base::do_init
+{
+public:
+  do_init()
+  {
+#if (OPENSSL_VERSION_NUMBER < 0x10100000L)
+    ::SSL_library_init();
+    ::SSL_load_error_strings();        
+    ::OpenSSL_add_all_algorithms();
+
+    mutexes_.resize(::CRYPTO_num_locks());
+    for (size_t i = 0; i < mutexes_.size(); ++i)
+      mutexes_[i].reset(new asio::detail::mutex);
+    ::CRYPTO_set_locking_callback(&do_init::openssl_locking_func);
+#endif // (OPENSSL_VERSION_NUMBER < 0x10100000L)
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+    ::CRYPTO_set_id_callback(&do_init::openssl_id_func);
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+
+#if !defined(SSL_OP_NO_COMPRESSION) \
+  && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+    null_compression_methods_ = sk_SSL_COMP_new_null();
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+       // && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+  }
+
+  ~do_init()
+  {
+#if !defined(SSL_OP_NO_COMPRESSION) \
+  && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+    sk_SSL_COMP_free(null_compression_methods_);
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+       // && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+    ::CRYPTO_set_id_callback(0);
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+#if (OPENSSL_VERSION_NUMBER < 0x10100000L)
+    ::CRYPTO_set_locking_callback(0);
+    ::ERR_free_strings();
+    ::EVP_cleanup();
+    ::CRYPTO_cleanup_all_ex_data();
+#endif // (OPENSSL_VERSION_NUMBER < 0x10100000L)
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+    ::ERR_remove_state(0);
+#elif (OPENSSL_VERSION_NUMBER < 0x10100000L)
+    ::ERR_remove_thread_state(NULL);
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+#if (OPENSSL_VERSION_NUMBER >= 0x10002000L) \
+    && (OPENSSL_VERSION_NUMBER < 0x10100000L) \
+    && !defined(SSL_OP_NO_COMPRESSION)
+    ::SSL_COMP_free_compression_methods();
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10002000L)
+       // && (OPENSSL_VERSION_NUMBER < 0x10100000L)
+       // && !defined(SSL_OP_NO_COMPRESSION)
+#if !defined(OPENSSL_IS_BORINGSSL)
+    ::CONF_modules_unload(1);
+#endif // !defined(OPENSSL_IS_BORINGSSL)
+#if !defined(OPENSSL_NO_ENGINE) \
+  && (OPENSSL_VERSION_NUMBER < 0x10100000L)
+    ::ENGINE_cleanup();
+#endif // !defined(OPENSSL_NO_ENGINE)
+       // && (OPENSSL_VERSION_NUMBER < 0x10100000L)
+  }
+
+#if !defined(SSL_OP_NO_COMPRESSION) \
+  && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+  STACK_OF(SSL_COMP)* get_null_compression_methods() const
+  {
+    return null_compression_methods_;
+  }
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+       // && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+
+private:
+#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
+  static unsigned long openssl_id_func()
+  {
+#if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    return ::GetCurrentThreadId();
+#else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+    void* id = &errno;
+    ASIO_ASSERT(sizeof(unsigned long) >= sizeof(void*));
+    return reinterpret_cast<unsigned long>(id);
+#endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
+  }
+#endif // (OPENSSL_VERSION_NUMBER < 0x10000000L)
+
+#if (OPENSSL_VERSION_NUMBER < 0x10100000L)
+  static void openssl_locking_func(int mode, int n, 
+    const char* /*file*/, int /*line*/)
+  {
+    if (mode & CRYPTO_LOCK)
+      instance()->mutexes_[n]->lock();
+    else
+      instance()->mutexes_[n]->unlock();
+  }
+
+  // Mutexes to be used in locking callbacks.
+  std::vector<asio::detail::shared_ptr<
+        asio::detail::mutex> > mutexes_;
+#endif // (OPENSSL_VERSION_NUMBER < 0x10100000L)
+
+#if !defined(SSL_OP_NO_COMPRESSION) \
+  && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+  STACK_OF(SSL_COMP)* null_compression_methods_;
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+       // && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+};
+
+asio::detail::shared_ptr<openssl_init_base::do_init>
+openssl_init_base::instance()
+{
+  static asio::detail::shared_ptr<do_init> init(new do_init);
+  return init;
+}
+
+#if !defined(SSL_OP_NO_COMPRESSION) \
+  && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+STACK_OF(SSL_COMP)* openssl_init_base::get_null_compression_methods()
+{
+  return instance()->get_null_compression_methods();
+}
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+       // && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_IMPL_OPENSSL_INIT_IPP
diff --git a/subprojects/asio/include/asio/ssl/detail/io.hpp b/subprojects/asio/include/asio/ssl/detail/io.hpp
new file mode 100644
index 000000000..0b0e51a20
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/io.hpp
@@ -0,0 +1,372 @@
+//
+// ssl/detail/io.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_IO_HPP
+#define ASIO_SSL_DETAIL_IO_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/ssl/detail/engine.hpp"
+#include "asio/ssl/detail/stream_core.hpp"
+#include "asio/write.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+template <typename Stream, typename Operation>
+std::size_t io(Stream& next_layer, stream_core& core,
+    const Operation& op, asio::error_code& ec)
+{
+  std::size_t bytes_transferred = 0;
+  do switch (op(core.engine_, ec, bytes_transferred))
+  {
+  case engine::want_input_and_retry:
+
+    // If the input buffer is empty then we need to read some more data from
+    // the underlying transport.
+    if (core.input_.size() == 0)
+      core.input_ = asio::buffer(core.input_buffer_,
+          next_layer.read_some(core.input_buffer_, ec));
+
+    // Pass the new input data to the engine.
+    core.input_ = core.engine_.put_input(core.input_);
+
+    // Try the operation again.
+    continue;
+
+  case engine::want_output_and_retry:
+
+    // Get output data from the engine and write it to the underlying
+    // transport.
+    asio::write(next_layer,
+        core.engine_.get_output(core.output_buffer_), ec);
+
+    // Try the operation again.
+    continue;
+
+  case engine::want_output:
+
+    // Get output data from the engine and write it to the underlying
+    // transport.
+    asio::write(next_layer,
+        core.engine_.get_output(core.output_buffer_), ec);
+
+    // Operation is complete. Return result to caller.
+    core.engine_.map_error_code(ec);
+    return bytes_transferred;
+
+  default:
+
+    // Operation is complete. Return result to caller.
+    core.engine_.map_error_code(ec);
+    return bytes_transferred;
+
+  } while (!ec);
+
+  // Operation failed. Return result to caller.
+  core.engine_.map_error_code(ec);
+  return 0;
+}
+
+template <typename Stream, typename Operation, typename Handler>
+class io_op
+{
+public:
+  io_op(Stream& next_layer, stream_core& core,
+      const Operation& op, Handler& handler)
+    : next_layer_(next_layer),
+      core_(core),
+      op_(op),
+      start_(0),
+      want_(engine::want_nothing),
+      bytes_transferred_(0),
+      handler_(ASIO_MOVE_CAST(Handler)(handler))
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE)
+  io_op(const io_op& other)
+    : next_layer_(other.next_layer_),
+      core_(other.core_),
+      op_(other.op_),
+      start_(other.start_),
+      want_(other.want_),
+      ec_(other.ec_),
+      bytes_transferred_(other.bytes_transferred_),
+      handler_(other.handler_)
+  {
+  }
+
+  io_op(io_op&& other)
+    : next_layer_(other.next_layer_),
+      core_(other.core_),
+      op_(ASIO_MOVE_CAST(Operation)(other.op_)),
+      start_(other.start_),
+      want_(other.want_),
+      ec_(other.ec_),
+      bytes_transferred_(other.bytes_transferred_),
+      handler_(ASIO_MOVE_CAST(Handler)(other.handler_))
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE)
+
+  void operator()(asio::error_code ec,
+      std::size_t bytes_transferred = ~std::size_t(0), int start = 0)
+  {
+    switch (start_ = start)
+    {
+    case 1: // Called after at least one async operation.
+      do
+      {
+        switch (want_ = op_(core_.engine_, ec_, bytes_transferred_))
+        {
+        case engine::want_input_and_retry:
+
+          // If the input buffer already has data in it we can pass it to the
+          // engine and then retry the operation immediately.
+          if (core_.input_.size() != 0)
+          {
+            core_.input_ = core_.engine_.put_input(core_.input_);
+            continue;
+          }
+
+          // The engine wants more data to be read from input. However, we
+          // cannot allow more than one read operation at a time on the
+          // underlying transport. The pending_read_ timer's expiry is set to
+          // pos_infin if a read is in progress, and neg_infin otherwise.
+          if (core_.expiry(core_.pending_read_) == core_.neg_infin())
+          {
+            // Prevent other read operations from being started.
+            core_.pending_read_.expires_at(core_.pos_infin());
+
+            // Start reading some data from the underlying transport.
+            next_layer_.async_read_some(
+                asio::buffer(core_.input_buffer_),
+                ASIO_MOVE_CAST(io_op)(*this));
+          }
+          else
+          {
+            // Wait until the current read operation completes.
+            core_.pending_read_.async_wait(ASIO_MOVE_CAST(io_op)(*this));
+          }
+
+          // Yield control until asynchronous operation completes. Control
+          // resumes at the "default:" label below.
+          return;
+
+        case engine::want_output_and_retry:
+        case engine::want_output:
+
+          // The engine wants some data to be written to the output. However, we
+          // cannot allow more than one write operation at a time on the
+          // underlying transport. The pending_write_ timer's expiry is set to
+          // pos_infin if a write is in progress, and neg_infin otherwise.
+          if (core_.expiry(core_.pending_write_) == core_.neg_infin())
+          {
+            // Prevent other write operations from being started.
+            core_.pending_write_.expires_at(core_.pos_infin());
+
+            // Start writing all the data to the underlying transport.
+            asio::async_write(next_layer_,
+                core_.engine_.get_output(core_.output_buffer_),
+                ASIO_MOVE_CAST(io_op)(*this));
+          }
+          else
+          {
+            // Wait until the current write operation completes.
+            core_.pending_write_.async_wait(ASIO_MOVE_CAST(io_op)(*this));
+          }
+
+          // Yield control until asynchronous operation completes. Control
+          // resumes at the "default:" label below.
+          return;
+
+        default:
+
+          // The SSL operation is done and we can invoke the handler, but we
+          // have to keep in mind that this function might be being called from
+          // the async operation's initiating function. In this case we're not
+          // allowed to call the handler directly. Instead, issue a zero-sized
+          // read so the handler runs "as-if" posted using io_context::post().
+          if (start)
+          {
+            next_layer_.async_read_some(
+                asio::buffer(core_.input_buffer_, 0),
+                ASIO_MOVE_CAST(io_op)(*this));
+
+            // Yield control until asynchronous operation completes. Control
+            // resumes at the "default:" label below.
+            return;
+          }
+          else
+          {
+            // Continue on to run handler directly.
+            break;
+          }
+        }
+
+        default:
+        if (bytes_transferred == ~std::size_t(0))
+          bytes_transferred = 0; // Timer cancellation, no data transferred.
+        else if (!ec_)
+          ec_ = ec;
+
+        switch (want_)
+        {
+        case engine::want_input_and_retry:
+
+          // Add received data to the engine's input.
+          core_.input_ = asio::buffer(
+              core_.input_buffer_, bytes_transferred);
+          core_.input_ = core_.engine_.put_input(core_.input_);
+
+          // Release any waiting read operations.
+          core_.pending_read_.expires_at(core_.neg_infin());
+
+          // Try the operation again.
+          continue;
+
+        case engine::want_output_and_retry:
+
+          // Release any waiting write operations.
+          core_.pending_write_.expires_at(core_.neg_infin());
+
+          // Try the operation again.
+          continue;
+
+        case engine::want_output:
+
+          // Release any waiting write operations.
+          core_.pending_write_.expires_at(core_.neg_infin());
+
+          // Fall through to call handler.
+
+        default:
+
+          // Pass the result to the handler.
+          op_.call_handler(handler_,
+              core_.engine_.map_error_code(ec_),
+              ec_ ? 0 : bytes_transferred_);
+
+          // Our work here is done.
+          return;
+        }
+      } while (!ec_);
+
+      // Operation failed. Pass the result to the handler.
+      op_.call_handler(handler_, core_.engine_.map_error_code(ec_), 0);
+    }
+  }
+
+//private:
+  Stream& next_layer_;
+  stream_core& core_;
+  Operation op_;
+  int start_;
+  engine::want want_;
+  asio::error_code ec_;
+  std::size_t bytes_transferred_;
+  Handler handler_;
+};
+
+template <typename Stream, typename Operation, typename Handler>
+inline void* asio_handler_allocate(std::size_t size,
+    io_op<Stream, Operation, Handler>* this_handler)
+{
+  return asio_handler_alloc_helpers::allocate(
+      size, this_handler->handler_);
+}
+
+template <typename Stream, typename Operation, typename Handler>
+inline void asio_handler_deallocate(void* pointer, std::size_t size,
+    io_op<Stream, Operation, Handler>* this_handler)
+{
+  asio_handler_alloc_helpers::deallocate(
+      pointer, size, this_handler->handler_);
+}
+
+template <typename Stream, typename Operation, typename Handler>
+inline bool asio_handler_is_continuation(
+    io_op<Stream, Operation, Handler>* this_handler)
+{
+  return this_handler->start_ == 0 ? true
+    : asio_handler_cont_helpers::is_continuation(this_handler->handler_);
+}
+
+template <typename Function, typename Stream,
+    typename Operation, typename Handler>
+inline void asio_handler_invoke(Function& function,
+    io_op<Stream, Operation, Handler>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Function, typename Stream,
+    typename Operation, typename Handler>
+inline void asio_handler_invoke(const Function& function,
+    io_op<Stream, Operation, Handler>* this_handler)
+{
+  asio_handler_invoke_helpers::invoke(
+      function, this_handler->handler_);
+}
+
+template <typename Stream, typename Operation, typename Handler>
+inline void async_io(Stream& next_layer, stream_core& core,
+    const Operation& op, Handler& handler)
+{
+  io_op<Stream, Operation, Handler>(
+    next_layer, core, op, handler)(
+      asio::error_code(), 0, 1);
+}
+
+} // namespace detail
+} // namespace ssl
+
+template <typename Stream, typename Operation,
+    typename Handler, typename Allocator>
+struct associated_allocator<
+    ssl::detail::io_op<Stream, Operation, Handler>, Allocator>
+{
+  typedef typename associated_allocator<Handler, Allocator>::type type;
+
+  static type get(const ssl::detail::io_op<Stream, Operation, Handler>& h,
+      const Allocator& a = Allocator()) ASIO_NOEXCEPT
+  {
+    return associated_allocator<Handler, Allocator>::get(h.handler_, a);
+  }
+};
+
+template <typename Stream, typename Operation,
+    typename Handler, typename Executor>
+struct associated_executor<
+    ssl::detail::io_op<Stream, Operation, Handler>, Executor>
+{
+  typedef typename associated_executor<Handler, Executor>::type type;
+
+  static type get(const ssl::detail::io_op<Stream, Operation, Handler>& h,
+      const Executor& ex = Executor()) ASIO_NOEXCEPT
+  {
+    return associated_executor<Handler, Executor>::get(h.handler_, ex);
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_IO_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/openssl_init.hpp b/subprojects/asio/include/asio/ssl/detail/openssl_init.hpp
new file mode 100644
index 000000000..c3e47278f
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/openssl_init.hpp
@@ -0,0 +1,101 @@
+//
+// ssl/detail/openssl_init.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_OPENSSL_INIT_HPP
+#define ASIO_SSL_DETAIL_OPENSSL_INIT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstring>
+#include "asio/detail/memory.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+class openssl_init_base
+  : private noncopyable
+{
+protected:
+  // Class that performs the actual initialisation.
+  class do_init;
+
+  // Helper function to manage a do_init singleton. The static instance of the
+  // openssl_init object ensures that this function is always called before
+  // main, and therefore before any other threads can get started. The do_init
+  // instance must be static in this function to ensure that it gets
+  // initialised before any other global objects try to use it.
+  ASIO_DECL static asio::detail::shared_ptr<do_init> instance();
+
+#if !defined(SSL_OP_NO_COMPRESSION) \
+  && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+  // Get an empty stack of compression methods, to be used when disabling
+  // compression.
+  ASIO_DECL static STACK_OF(SSL_COMP)* get_null_compression_methods();
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+       // && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+};
+
+template <bool Do_Init = true>
+class openssl_init : private openssl_init_base
+{
+public:
+  // Constructor.
+  openssl_init()
+    : ref_(instance())
+  {
+    using namespace std; // For memmove.
+
+    // Ensure openssl_init::instance_ is linked in.
+    openssl_init* tmp = &instance_;
+    memmove(&tmp, &tmp, sizeof(openssl_init*));
+  }
+
+  // Destructor.
+  ~openssl_init()
+  {
+  }
+
+#if !defined(SSL_OP_NO_COMPRESSION) \
+  && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+  using openssl_init_base::get_null_compression_methods;
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+       // && (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+
+private:
+  // Instance to force initialisation of openssl at global scope.
+  static openssl_init instance_;
+
+  // Reference to singleton do_init object to ensure that openssl does not get
+  // cleaned up until the last user has finished with it.
+  asio::detail::shared_ptr<do_init> ref_;
+};
+
+template <bool Do_Init>
+openssl_init<Do_Init> openssl_init<Do_Init>::instance_;
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ssl/detail/impl/openssl_init.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_SSL_DETAIL_OPENSSL_INIT_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/openssl_types.hpp b/subprojects/asio/include/asio/ssl/detail/openssl_types.hpp
new file mode 100644
index 000000000..a044af30d
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/openssl_types.hpp
@@ -0,0 +1,30 @@
+//
+// ssl/detail/openssl_types.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_OPENSSL_TYPES_HPP
+#define ASIO_SSL_DETAIL_OPENSSL_TYPES_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/socket_types.hpp"
+#include <openssl/conf.h>
+#include <openssl/ssl.h>
+#if !defined(OPENSSL_NO_ENGINE)
+# include <openssl/engine.h>
+#endif // !defined(OPENSSL_NO_ENGINE)
+#include <openssl/dh.h>
+#include <openssl/err.h>
+#include <openssl/rsa.h>
+#include <openssl/x509v3.h>
+
+#endif // ASIO_SSL_DETAIL_OPENSSL_TYPES_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/password_callback.hpp b/subprojects/asio/include/asio/ssl/detail/password_callback.hpp
new file mode 100644
index 000000000..9b1dbeeb8
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/password_callback.hpp
@@ -0,0 +1,66 @@
+//
+// ssl/detail/password_callback.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_PASSWORD_CALLBACK_HPP
+#define ASIO_SSL_DETAIL_PASSWORD_CALLBACK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cstddef>
+#include <string>
+#include "asio/ssl/context_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+class password_callback_base
+{
+public:
+  virtual ~password_callback_base()
+  {
+  }
+
+  virtual std::string call(std::size_t size,
+      context_base::password_purpose purpose) = 0;
+};
+
+template <typename PasswordCallback>
+class password_callback : public password_callback_base
+{
+public:
+  explicit password_callback(PasswordCallback callback)
+    : callback_(callback)
+  {
+  }
+
+  virtual std::string call(std::size_t size,
+      context_base::password_purpose purpose)
+  {
+    return callback_(size, purpose);
+  }
+
+private:
+  PasswordCallback callback_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_PASSWORD_CALLBACK_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/read_op.hpp b/subprojects/asio/include/asio/ssl/detail/read_op.hpp
new file mode 100644
index 000000000..b0d6de266
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/read_op.hpp
@@ -0,0 +1,67 @@
+//
+// ssl/detail/read_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_READ_OP_HPP
+#define ASIO_SSL_DETAIL_READ_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/ssl/detail/engine.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+template <typename MutableBufferSequence>
+class read_op
+{
+public:
+  read_op(const MutableBufferSequence& buffers)
+    : buffers_(buffers)
+  {
+  }
+
+  engine::want operator()(engine& eng,
+      asio::error_code& ec,
+      std::size_t& bytes_transferred) const
+  {
+    asio::mutable_buffer buffer =
+      asio::detail::buffer_sequence_adapter<asio::mutable_buffer,
+        MutableBufferSequence>::first(buffers_);
+
+    return eng.read(buffer, ec, bytes_transferred);
+  }
+
+  template <typename Handler>
+  void call_handler(Handler& handler,
+      const asio::error_code& ec,
+      const std::size_t& bytes_transferred) const
+  {
+    handler(ec, bytes_transferred);
+  }
+
+private:
+  MutableBufferSequence buffers_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_READ_OP_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/shutdown_op.hpp b/subprojects/asio/include/asio/ssl/detail/shutdown_op.hpp
new file mode 100644
index 000000000..d20b4309e
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/shutdown_op.hpp
@@ -0,0 +1,54 @@
+//
+// ssl/detail/shutdown_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_SHUTDOWN_OP_HPP
+#define ASIO_SSL_DETAIL_SHUTDOWN_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/ssl/detail/engine.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+class shutdown_op
+{
+public:
+  engine::want operator()(engine& eng,
+      asio::error_code& ec,
+      std::size_t& bytes_transferred) const
+  {
+    bytes_transferred = 0;
+    return eng.shutdown(ec);
+  }
+
+  template <typename Handler>
+  void call_handler(Handler& handler,
+      const asio::error_code& ec,
+      const std::size_t&) const
+  {
+    handler(ec);
+  }
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_SHUTDOWN_OP_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/stream_core.hpp b/subprojects/asio/include/asio/ssl/detail/stream_core.hpp
new file mode 100644
index 000000000..13fde74bf
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/stream_core.hpp
@@ -0,0 +1,134 @@
+//
+// ssl/detail/stream_core.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_STREAM_CORE_HPP
+#define ASIO_SSL_DETAIL_STREAM_CORE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+# include "asio/deadline_timer.hpp"
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+# include "asio/steady_timer.hpp"
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+#include "asio/ssl/detail/engine.hpp"
+#include "asio/buffer.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+struct stream_core
+{
+  // According to the OpenSSL documentation, this is the buffer size that is
+  // sufficient to hold the largest possible TLS record.
+  enum { max_tls_record_size = 17 * 1024 };
+
+  stream_core(SSL_CTX* context, asio::io_context& io_context)
+    : engine_(context),
+      pending_read_(io_context),
+      pending_write_(io_context),
+      output_buffer_space_(max_tls_record_size),
+      output_buffer_(asio::buffer(output_buffer_space_)),
+      input_buffer_space_(max_tls_record_size),
+      input_buffer_(asio::buffer(input_buffer_space_))
+  {
+    pending_read_.expires_at(neg_infin());
+    pending_write_.expires_at(neg_infin());
+  }
+
+  ~stream_core()
+  {
+  }
+
+  // The SSL engine.
+  engine engine_;
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+  // Timer used for storing queued read operations.
+  asio::deadline_timer pending_read_;
+
+  // Timer used for storing queued write operations.
+  asio::deadline_timer pending_write_;
+
+  // Helper function for obtaining a time value that always fires.
+  static asio::deadline_timer::time_type neg_infin()
+  {
+    return boost::posix_time::neg_infin;
+  }
+
+  // Helper function for obtaining a time value that never fires.
+  static asio::deadline_timer::time_type pos_infin()
+  {
+    return boost::posix_time::pos_infin;
+  }
+
+  // Helper function to get a timer's expiry time.
+  static asio::deadline_timer::time_type expiry(
+      const asio::deadline_timer& timer)
+  {
+    return timer.expires_at();
+  }
+#else // defined(ASIO_HAS_BOOST_DATE_TIME)
+  // Timer used for storing queued read operations.
+  asio::steady_timer pending_read_;
+
+  // Timer used for storing queued write operations.
+  asio::steady_timer pending_write_;
+
+  // Helper function for obtaining a time value that always fires.
+  static asio::steady_timer::time_point neg_infin()
+  {
+    return (asio::steady_timer::time_point::min)();
+  }
+
+  // Helper function for obtaining a time value that never fires.
+  static asio::steady_timer::time_point pos_infin()
+  {
+    return (asio::steady_timer::time_point::max)();
+  }
+
+  // Helper function to get a timer's expiry time.
+  static asio::steady_timer::time_point expiry(
+      const asio::steady_timer& timer)
+  {
+    return timer.expiry();
+  }
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+
+  // Buffer space used to prepare output intended for the transport.
+  std::vector<unsigned char> output_buffer_space_;
+
+  // A buffer that may be used to prepare output intended for the transport.
+  const asio::mutable_buffer output_buffer_;
+
+  // Buffer space used to read input intended for the engine.
+  std::vector<unsigned char> input_buffer_space_;
+
+  // A buffer that may be used to read input intended for the engine.
+  const asio::mutable_buffer input_buffer_;
+
+  // The buffer pointing to the engine's unconsumed input.
+  asio::const_buffer input_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_STREAM_CORE_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/verify_callback.hpp b/subprojects/asio/include/asio/ssl/detail/verify_callback.hpp
new file mode 100644
index 000000000..1c56a27d8
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/verify_callback.hpp
@@ -0,0 +1,62 @@
+//
+// ssl/detail/verify_callback.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_VERIFY_CALLBACK_HPP
+#define ASIO_SSL_DETAIL_VERIFY_CALLBACK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/ssl/verify_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+class verify_callback_base
+{
+public:
+  virtual ~verify_callback_base()
+  {
+  }
+
+  virtual bool call(bool preverified, verify_context& ctx) = 0;
+};
+
+template <typename VerifyCallback>
+class verify_callback : public verify_callback_base
+{
+public:
+  explicit verify_callback(VerifyCallback callback)
+    : callback_(callback)
+  {
+  }
+
+  virtual bool call(bool preverified, verify_context& ctx)
+  {
+    return callback_(preverified, ctx);
+  }
+
+private:
+  VerifyCallback callback_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_VERIFY_CALLBACK_HPP
diff --git a/subprojects/asio/include/asio/ssl/detail/write_op.hpp b/subprojects/asio/include/asio/ssl/detail/write_op.hpp
new file mode 100644
index 000000000..1d341c09d
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/detail/write_op.hpp
@@ -0,0 +1,67 @@
+//
+// ssl/detail/write_op.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_DETAIL_WRITE_OP_HPP
+#define ASIO_SSL_DETAIL_WRITE_OP_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/ssl/detail/engine.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+namespace detail {
+
+template <typename ConstBufferSequence>
+class write_op
+{
+public:
+  write_op(const ConstBufferSequence& buffers)
+    : buffers_(buffers)
+  {
+  }
+
+  engine::want operator()(engine& eng,
+      asio::error_code& ec,
+      std::size_t& bytes_transferred) const
+  {
+    asio::const_buffer buffer =
+      asio::detail::buffer_sequence_adapter<asio::const_buffer,
+        ConstBufferSequence>::first(buffers_);
+
+    return eng.write(buffer, ec, bytes_transferred);
+  }
+
+  template <typename Handler>
+  void call_handler(Handler& handler,
+      const asio::error_code& ec,
+      const std::size_t& bytes_transferred) const
+  {
+    handler(ec, bytes_transferred);
+  }
+
+private:
+  ConstBufferSequence buffers_;
+};
+
+} // namespace detail
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_DETAIL_WRITE_OP_HPP
diff --git a/subprojects/asio/include/asio/ssl/error.hpp b/subprojects/asio/include/asio/ssl/error.hpp
new file mode 100644
index 000000000..6165c5cf7
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/error.hpp
@@ -0,0 +1,111 @@
+//
+// ssl/error.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_ERROR_HPP
+#define ASIO_SSL_ERROR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/error_code.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace error {
+
+enum ssl_errors
+{
+  // Error numbers are those produced by openssl.
+};
+
+extern ASIO_DECL
+const asio::error_category& get_ssl_category();
+
+static const asio::error_category&
+  ssl_category ASIO_UNUSED_VARIABLE
+  = asio::error::get_ssl_category();
+
+} // namespace error
+namespace ssl {
+namespace error {
+
+enum stream_errors
+{
+#if defined(GENERATING_DOCUMENTATION)
+  /// The underlying stream closed before the ssl stream gracefully shut down.
+  stream_truncated
+#elif (OPENSSL_VERSION_NUMBER < 0x10100000L) && !defined(OPENSSL_IS_BORINGSSL)
+  stream_truncated = ERR_PACK(ERR_LIB_SSL, 0, SSL_R_SHORT_READ)
+#else
+  stream_truncated = 1
+#endif
+};
+
+extern ASIO_DECL
+const asio::error_category& get_stream_category();
+
+static const asio::error_category&
+  stream_category ASIO_UNUSED_VARIABLE
+  = asio::ssl::error::get_stream_category();
+
+} // namespace error
+} // namespace ssl
+} // namespace asio
+
+#if defined(ASIO_HAS_STD_SYSTEM_ERROR)
+namespace std {
+
+template<> struct is_error_code_enum<asio::error::ssl_errors>
+{
+  static const bool value = true;
+};
+
+template<> struct is_error_code_enum<asio::ssl::error::stream_errors>
+{
+  static const bool value = true;
+};
+
+} // namespace std
+#endif // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+namespace asio {
+namespace error {
+
+inline asio::error_code make_error_code(ssl_errors e)
+{
+  return asio::error_code(
+      static_cast<int>(e), get_ssl_category());
+}
+
+} // namespace error
+namespace ssl {
+namespace error {
+
+inline asio::error_code make_error_code(stream_errors e)
+{
+  return asio::error_code(
+      static_cast<int>(e), get_stream_category());
+}
+
+} // namespace error
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ssl/impl/error.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_SSL_ERROR_HPP
diff --git a/subprojects/asio/include/asio/ssl/impl/context.hpp b/subprojects/asio/include/asio/ssl/impl/context.hpp
new file mode 100644
index 000000000..40199c143
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/impl/context.hpp
@@ -0,0 +1,67 @@
+//
+// ssl/impl/context.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2005 Voipster / Indrek dot Juhani at voipster dot com
+// Copyright (c) 2005-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_IMPL_CONTEXT_HPP
+#define ASIO_SSL_IMPL_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/throw_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+template <typename VerifyCallback>
+void context::set_verify_callback(VerifyCallback callback)
+{
+  asio::error_code ec;
+  this->set_verify_callback(callback, ec);
+  asio::detail::throw_error(ec, "set_verify_callback");
+}
+
+template <typename VerifyCallback>
+ASIO_SYNC_OP_VOID context::set_verify_callback(
+    VerifyCallback callback, asio::error_code& ec)
+{
+  do_set_verify_callback(
+      new detail::verify_callback<VerifyCallback>(callback), ec);
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+template <typename PasswordCallback>
+void context::set_password_callback(PasswordCallback callback)
+{
+  asio::error_code ec;
+  this->set_password_callback(callback, ec);
+  asio::detail::throw_error(ec, "set_password_callback");
+}
+
+template <typename PasswordCallback>
+ASIO_SYNC_OP_VOID context::set_password_callback(
+    PasswordCallback callback, asio::error_code& ec)
+{
+  do_set_password_callback(
+      new detail::password_callback<PasswordCallback>(callback), ec);
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_IMPL_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/ssl/impl/context.ipp b/subprojects/asio/include/asio/ssl/impl/context.ipp
new file mode 100644
index 000000000..3bc3f295c
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/impl/context.ipp
@@ -0,0 +1,1204 @@
+//
+// ssl/impl/context.ipp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2005 Voipster / Indrek dot Juhani at voipster dot com
+// Copyright (c) 2005-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_IMPL_CONTEXT_IPP
+#define ASIO_SSL_IMPL_CONTEXT_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cstring>
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/ssl/context.hpp"
+#include "asio/ssl/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+struct context::bio_cleanup
+{
+  BIO* p;
+  ~bio_cleanup() { if (p) ::BIO_free(p); }
+};
+
+struct context::x509_cleanup
+{
+  X509* p;
+  ~x509_cleanup() { if (p) ::X509_free(p); }
+};
+
+struct context::evp_pkey_cleanup
+{
+  EVP_PKEY* p;
+  ~evp_pkey_cleanup() { if (p) ::EVP_PKEY_free(p); }
+};
+
+struct context::rsa_cleanup
+{
+  RSA* p;
+  ~rsa_cleanup() { if (p) ::RSA_free(p); }
+};
+
+struct context::dh_cleanup
+{
+  DH* p;
+  ~dh_cleanup() { if (p) ::DH_free(p); }
+};
+
+context::context(context::method m)
+  : handle_(0)
+{
+  ::ERR_clear_error();
+
+  switch (m)
+  {
+    // SSL v2.
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) || defined(OPENSSL_NO_SSL2)
+  case context::sslv2:
+  case context::sslv2_client:
+  case context::sslv2_server:
+    asio::detail::throw_error(
+        asio::error::invalid_argument, "context");
+    break;
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L) || defined(OPENSSL_NO_SSL2)
+  case context::sslv2:
+    handle_ = ::SSL_CTX_new(::SSLv2_method());
+    break;
+  case context::sslv2_client:
+    handle_ = ::SSL_CTX_new(::SSLv2_client_method());
+    break;
+  case context::sslv2_server:
+    handle_ = ::SSL_CTX_new(::SSLv2_server_method());
+    break;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L) || defined(OPENSSL_NO_SSL2)
+
+    // SSL v3.
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+  case context::sslv3:
+    handle_ = ::SSL_CTX_new(::TLS_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, SSL3_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, SSL3_VERSION);
+    }
+    break;
+  case context::sslv3_client:
+    handle_ = ::SSL_CTX_new(::TLS_client_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, SSL3_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, SSL3_VERSION);
+    }
+    break;
+  case context::sslv3_server:
+    handle_ = ::SSL_CTX_new(::TLS_server_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, SSL3_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, SSL3_VERSION);
+    }
+    break;
+#elif defined(OPENSSL_NO_SSL3)
+  case context::sslv3:
+  case context::sslv3_client:
+  case context::sslv3_server:
+    asio::detail::throw_error(
+        asio::error::invalid_argument, "context");
+    break;
+#else // defined(OPENSSL_NO_SSL3)
+  case context::sslv3:
+    handle_ = ::SSL_CTX_new(::SSLv3_method());
+    break;
+  case context::sslv3_client:
+    handle_ = ::SSL_CTX_new(::SSLv3_client_method());
+    break;
+  case context::sslv3_server:
+    handle_ = ::SSL_CTX_new(::SSLv3_server_method());
+    break;
+#endif // defined(OPENSSL_NO_SSL3)
+
+    // TLS v1.0.
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+  case context::tlsv1:
+    handle_ = ::SSL_CTX_new(::TLS_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_VERSION);
+    }
+    break;
+  case context::tlsv1_client:
+    handle_ = ::SSL_CTX_new(::TLS_client_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_VERSION);
+    }
+    break;
+  case context::tlsv1_server:
+    handle_ = ::SSL_CTX_new(::TLS_server_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_VERSION);
+    }
+    break;
+#elif defined(SSL_TXT_TLSV1)
+  case context::tlsv1:
+    handle_ = ::SSL_CTX_new(::TLSv1_method());
+    break;
+  case context::tlsv1_client:
+    handle_ = ::SSL_CTX_new(::TLSv1_client_method());
+    break;
+  case context::tlsv1_server:
+    handle_ = ::SSL_CTX_new(::TLSv1_server_method());
+    break;
+#else // defined(SSL_TXT_TLSV1)
+  case context::tlsv1:
+  case context::tlsv1_client:
+  case context::tlsv1_server:
+    asio::detail::throw_error(
+        asio::error::invalid_argument, "context");
+    break;
+#endif // defined(SSL_TXT_TLSV1)
+
+    // TLS v1.1.
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+  case context::tlsv11:
+    handle_ = ::SSL_CTX_new(::TLS_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_1_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_1_VERSION);
+    }
+    break;
+  case context::tlsv11_client:
+    handle_ = ::SSL_CTX_new(::TLS_client_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_1_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_1_VERSION);
+    }
+    break;
+  case context::tlsv11_server:
+    handle_ = ::SSL_CTX_new(::TLS_server_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_1_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_1_VERSION);
+    }
+    break;
+#elif defined(SSL_TXT_TLSV1_1)
+  case context::tlsv11:
+    handle_ = ::SSL_CTX_new(::TLSv1_1_method());
+    break;
+  case context::tlsv11_client:
+    handle_ = ::SSL_CTX_new(::TLSv1_1_client_method());
+    break;
+  case context::tlsv11_server:
+    handle_ = ::SSL_CTX_new(::TLSv1_1_server_method());
+    break;
+#else // defined(SSL_TXT_TLSV1_1)
+  case context::tlsv11:
+  case context::tlsv11_client:
+  case context::tlsv11_server:
+    asio::detail::throw_error(
+        asio::error::invalid_argument, "context");
+    break;
+#endif // defined(SSL_TXT_TLSV1_1)
+
+    // TLS v1.2.
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+  case context::tlsv12:
+    handle_ = ::SSL_CTX_new(::TLS_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_2_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_2_VERSION);
+    }
+    break;
+  case context::tlsv12_client:
+    handle_ = ::SSL_CTX_new(::TLS_client_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_2_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_2_VERSION);
+    }
+    break;
+  case context::tlsv12_server:
+    handle_ = ::SSL_CTX_new(::TLS_server_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_2_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_2_VERSION);
+    }
+    break;
+#elif defined(SSL_TXT_TLSV1_2)
+  case context::tlsv12:
+    handle_ = ::SSL_CTX_new(::TLSv1_2_method());
+    break;
+  case context::tlsv12_client:
+    handle_ = ::SSL_CTX_new(::TLSv1_2_client_method());
+    break;
+  case context::tlsv12_server:
+    handle_ = ::SSL_CTX_new(::TLSv1_2_server_method());
+    break;
+#else // defined(SSL_TXT_TLSV1_2)
+  case context::tlsv12:
+  case context::tlsv12_client:
+  case context::tlsv12_server:
+    asio::detail::throw_error(
+        asio::error::invalid_argument, "context");
+    break;
+#endif // defined(SSL_TXT_TLSV1_2)
+
+    // TLS v1.3.
+#if (OPENSSL_VERSION_NUMBER >= 0x10101000L) \
+    && !defined(LIBRESSL_VERSION_NUMBER)
+  case context::tlsv13:
+    handle_ = ::SSL_CTX_new(::TLS_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_3_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_3_VERSION);
+    }
+    break;
+  case context::tlsv13_client:
+    handle_ = ::SSL_CTX_new(::TLS_client_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_3_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_3_VERSION);
+    }
+    break;
+  case context::tlsv13_server:
+    handle_ = ::SSL_CTX_new(::TLS_server_method());
+    if (handle_)
+    {
+      SSL_CTX_set_min_proto_version(handle_, TLS1_3_VERSION);
+      SSL_CTX_set_max_proto_version(handle_, TLS1_3_VERSION);
+    }
+    break;
+#else // (OPENSSL_VERSION_NUMBER >= 0x10101000L)
+      //   && !defined(LIBRESSL_VERSION_NUMBER)
+  case context::tlsv13:
+  case context::tlsv13_client:
+  case context::tlsv13_server:
+    asio::detail::throw_error(
+        asio::error::invalid_argument, "context");
+    break;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10101000L)
+       //   && !defined(LIBRESSL_VERSION_NUMBER)
+
+    // Any supported SSL/TLS version.
+  case context::sslv23:
+    handle_ = ::SSL_CTX_new(::SSLv23_method());
+    break;
+  case context::sslv23_client:
+    handle_ = ::SSL_CTX_new(::SSLv23_client_method());
+    break;
+  case context::sslv23_server:
+    handle_ = ::SSL_CTX_new(::SSLv23_server_method());
+    break;
+
+    // Any supported TLS version.
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+  case context::tls:
+    handle_ = ::SSL_CTX_new(::TLS_method());
+    if (handle_)
+      SSL_CTX_set_min_proto_version(handle_, TLS1_VERSION);
+    break;
+  case context::tls_client:
+    handle_ = ::SSL_CTX_new(::TLS_client_method());
+    if (handle_)
+      SSL_CTX_set_min_proto_version(handle_, TLS1_VERSION);
+    break;
+  case context::tls_server:
+    handle_ = ::SSL_CTX_new(::TLS_server_method());
+    if (handle_)
+      SSL_CTX_set_min_proto_version(handle_, TLS1_VERSION);
+    break;
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+  case context::tls:
+    handle_ = ::SSL_CTX_new(::SSLv23_method());
+    if (handle_)
+      SSL_CTX_set_options(handle_, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
+    break;
+  case context::tls_client:
+    handle_ = ::SSL_CTX_new(::SSLv23_client_method());
+    if (handle_)
+      SSL_CTX_set_options(handle_, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
+    break;
+  case context::tls_server:
+    handle_ = ::SSL_CTX_new(::SSLv23_server_method());
+    if (handle_)
+      SSL_CTX_set_options(handle_, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
+    break;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+
+  default:
+    handle_ = ::SSL_CTX_new(0);
+    break;
+  }
+
+  if (handle_ == 0)
+  {
+    asio::error_code ec(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    asio::detail::throw_error(ec, "context");
+  }
+
+  set_options(no_compression);
+}
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+context::context(context&& other)
+{
+  handle_ = other.handle_;
+  other.handle_ = 0;
+}
+
+context& context::operator=(context&& other)
+{
+  context tmp(ASIO_MOVE_CAST(context)(*this));
+  handle_ = other.handle_;
+  other.handle_ = 0;
+  return *this;
+}
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+context::~context()
+{
+  if (handle_)
+  {
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+    void* cb_userdata = ::SSL_CTX_get_default_passwd_cb_userdata(handle_);
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+    void* cb_userdata = handle_->default_passwd_callback_userdata;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+    if (cb_userdata)
+    {
+      detail::password_callback_base* callback =
+        static_cast<detail::password_callback_base*>(
+            cb_userdata);
+      delete callback;
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+      ::SSL_CTX_set_default_passwd_cb_userdata(handle_, 0);
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+      handle_->default_passwd_callback_userdata = 0;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+    }
+
+    if (SSL_CTX_get_app_data(handle_))
+    {
+      detail::verify_callback_base* callback =
+        static_cast<detail::verify_callback_base*>(
+            SSL_CTX_get_app_data(handle_));
+      delete callback;
+      SSL_CTX_set_app_data(handle_, 0);
+    }
+
+    ::SSL_CTX_free(handle_);
+  }
+}
+
+context::native_handle_type context::native_handle()
+{
+  return handle_;
+}
+
+void context::clear_options(context::options o)
+{
+  asio::error_code ec;
+  clear_options(o, ec);
+  asio::detail::throw_error(ec, "clear_options");
+}
+
+ASIO_SYNC_OP_VOID context::clear_options(
+    context::options o, asio::error_code& ec)
+{
+#if (OPENSSL_VERSION_NUMBER >= 0x009080DFL) \
+  && (OPENSSL_VERSION_NUMBER != 0x00909000L)
+# if !defined(SSL_OP_NO_COMPRESSION)
+  if ((o & context::no_compression) != 0)
+  {
+# if (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+    handle_->comp_methods = SSL_COMP_get_compression_methods();
+# endif // (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+    o ^= context::no_compression;
+  }
+# endif // !defined(SSL_OP_NO_COMPRESSION)
+
+  ::SSL_CTX_clear_options(handle_, o);
+
+  ec = asio::error_code();
+#else // (OPENSSL_VERSION_NUMBER >= 0x009080DFL)
+      //   && (OPENSSL_VERSION_NUMBER != 0x00909000L)
+  (void)o;
+  ec = asio::error::operation_not_supported;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x009080DFL)
+       //   && (OPENSSL_VERSION_NUMBER != 0x00909000L)
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::set_options(context::options o)
+{
+  asio::error_code ec;
+  set_options(o, ec);
+  asio::detail::throw_error(ec, "set_options");
+}
+
+ASIO_SYNC_OP_VOID context::set_options(
+    context::options o, asio::error_code& ec)
+{
+#if !defined(SSL_OP_NO_COMPRESSION)
+  if ((o & context::no_compression) != 0)
+  {
+#if (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+    handle_->comp_methods =
+      asio::ssl::detail::openssl_init<>::get_null_compression_methods();
+#endif // (OPENSSL_VERSION_NUMBER >= 0x00908000L)
+    o ^= context::no_compression;
+  }
+#endif // !defined(SSL_OP_NO_COMPRESSION)
+
+  ::SSL_CTX_set_options(handle_, o);
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::set_verify_mode(verify_mode v)
+{
+  asio::error_code ec;
+  set_verify_mode(v, ec);
+  asio::detail::throw_error(ec, "set_verify_mode");
+}
+
+ASIO_SYNC_OP_VOID context::set_verify_mode(
+    verify_mode v, asio::error_code& ec)
+{
+  ::SSL_CTX_set_verify(handle_, v, ::SSL_CTX_get_verify_callback(handle_));
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::set_verify_depth(int depth)
+{
+  asio::error_code ec;
+  set_verify_depth(depth, ec);
+  asio::detail::throw_error(ec, "set_verify_depth");
+}
+
+ASIO_SYNC_OP_VOID context::set_verify_depth(
+    int depth, asio::error_code& ec)
+{
+  ::SSL_CTX_set_verify_depth(handle_, depth);
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::load_verify_file(const std::string& filename)
+{
+  asio::error_code ec;
+  load_verify_file(filename, ec);
+  asio::detail::throw_error(ec, "load_verify_file");
+}
+
+ASIO_SYNC_OP_VOID context::load_verify_file(
+    const std::string& filename, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  if (::SSL_CTX_load_verify_locations(handle_, filename.c_str(), 0) != 1)
+  {
+    ec = asio::error_code(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::add_certificate_authority(const const_buffer& ca)
+{
+  asio::error_code ec;
+  add_certificate_authority(ca, ec);
+  asio::detail::throw_error(ec, "add_certificate_authority");
+}
+
+ASIO_SYNC_OP_VOID context::add_certificate_authority(
+    const const_buffer& ca, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  bio_cleanup bio = { make_buffer_bio(ca) };
+  if (bio.p)
+  {
+    if (X509_STORE* store = ::SSL_CTX_get_cert_store(handle_))
+    {
+      for (;;)
+      {
+        x509_cleanup cert = { ::PEM_read_bio_X509(bio.p, 0, 0, 0) };
+        if (!cert.p)
+          break;
+
+        if (::X509_STORE_add_cert(store, cert.p) != 1)
+        {
+          ec = asio::error_code(
+              static_cast<int>(::ERR_get_error()),
+              asio::error::get_ssl_category());
+          ASIO_SYNC_OP_VOID_RETURN(ec);
+        }
+      }
+    }
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::set_default_verify_paths()
+{
+  asio::error_code ec;
+  set_default_verify_paths(ec);
+  asio::detail::throw_error(ec, "set_default_verify_paths");
+}
+
+ASIO_SYNC_OP_VOID context::set_default_verify_paths(
+    asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  if (::SSL_CTX_set_default_verify_paths(handle_) != 1)
+  {
+    ec = asio::error_code(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::add_verify_path(const std::string& path)
+{
+  asio::error_code ec;
+  add_verify_path(path, ec);
+  asio::detail::throw_error(ec, "add_verify_path");
+}
+
+ASIO_SYNC_OP_VOID context::add_verify_path(
+    const std::string& path, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  if (::SSL_CTX_load_verify_locations(handle_, 0, path.c_str()) != 1)
+  {
+    ec = asio::error_code(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_certificate(
+    const const_buffer& certificate, file_format format)
+{
+  asio::error_code ec;
+  use_certificate(certificate, format, ec);
+  asio::detail::throw_error(ec, "use_certificate");
+}
+
+ASIO_SYNC_OP_VOID context::use_certificate(
+    const const_buffer& certificate, file_format format,
+    asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  if (format == context_base::asn1)
+  {
+    if (::SSL_CTX_use_certificate_ASN1(handle_,
+          static_cast<int>(certificate.size()),
+          static_cast<const unsigned char*>(certificate.data())) == 1)
+    {
+      ec = asio::error_code();
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+  }
+  else if (format == context_base::pem)
+  {
+    bio_cleanup bio = { make_buffer_bio(certificate) };
+    if (bio.p)
+    {
+      x509_cleanup cert = { ::PEM_read_bio_X509(bio.p, 0, 0, 0) };
+      if (cert.p)
+      {
+        if (::SSL_CTX_use_certificate(handle_, cert.p) == 1)
+        {
+          ec = asio::error_code();
+          ASIO_SYNC_OP_VOID_RETURN(ec);
+        }
+      }
+    }
+  }
+  else
+  {
+    ec = asio::error::invalid_argument;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code(
+      static_cast<int>(::ERR_get_error()),
+      asio::error::get_ssl_category());
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_certificate_file(
+    const std::string& filename, file_format format)
+{
+  asio::error_code ec;
+  use_certificate_file(filename, format, ec);
+  asio::detail::throw_error(ec, "use_certificate_file");
+}
+
+ASIO_SYNC_OP_VOID context::use_certificate_file(
+    const std::string& filename, file_format format,
+    asio::error_code& ec)
+{
+  int file_type;
+  switch (format)
+  {
+  case context_base::asn1:
+    file_type = SSL_FILETYPE_ASN1;
+    break;
+  case context_base::pem:
+    file_type = SSL_FILETYPE_PEM;
+    break;
+  default:
+    {
+      ec = asio::error::invalid_argument;
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+  }
+
+  ::ERR_clear_error();
+
+  if (::SSL_CTX_use_certificate_file(handle_, filename.c_str(), file_type) != 1)
+  {
+    ec = asio::error_code(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_certificate_chain(const const_buffer& chain)
+{
+  asio::error_code ec;
+  use_certificate_chain(chain, ec);
+  asio::detail::throw_error(ec, "use_certificate_chain");
+}
+
+ASIO_SYNC_OP_VOID context::use_certificate_chain(
+    const const_buffer& chain, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  bio_cleanup bio = { make_buffer_bio(chain) };
+  if (bio.p)
+  {
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+    pem_password_cb* callback = ::SSL_CTX_get_default_passwd_cb(handle_);
+    void* cb_userdata = ::SSL_CTX_get_default_passwd_cb_userdata(handle_);
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+    pem_password_cb* callback = handle_->default_passwd_callback;
+    void* cb_userdata = handle_->default_passwd_callback_userdata;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+    x509_cleanup cert = {
+      ::PEM_read_bio_X509_AUX(bio.p, 0,
+          callback,
+          cb_userdata) };
+    if (!cert.p)
+    {
+      ec = asio::error_code(ERR_R_PEM_LIB,
+          asio::error::get_ssl_category());
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+
+    int result = ::SSL_CTX_use_certificate(handle_, cert.p);
+    if (result == 0 || ::ERR_peek_error() != 0)
+    {
+      ec = asio::error_code(
+          static_cast<int>(::ERR_get_error()),
+          asio::error::get_ssl_category());
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+
+#if (OPENSSL_VERSION_NUMBER >= 0x10002000L) && !defined(LIBRESSL_VERSION_NUMBER)
+    ::SSL_CTX_clear_chain_certs(handle_);
+#else
+    if (handle_->extra_certs)
+    {
+      ::sk_X509_pop_free(handle_->extra_certs, X509_free);
+      handle_->extra_certs = 0;
+    }
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10002000L)
+
+    while (X509* cacert = ::PEM_read_bio_X509(bio.p, 0,
+          callback,
+          cb_userdata))
+    {
+      if (!::SSL_CTX_add_extra_chain_cert(handle_, cacert))
+      {
+        ec = asio::error_code(
+            static_cast<int>(::ERR_get_error()),
+            asio::error::get_ssl_category());
+        ASIO_SYNC_OP_VOID_RETURN(ec);
+      }
+    }
+  
+    result = ::ERR_peek_last_error();
+    if ((ERR_GET_LIB(result) == ERR_LIB_PEM)
+        && (ERR_GET_REASON(result) == PEM_R_NO_START_LINE))
+    {
+      ::ERR_clear_error();
+      ec = asio::error_code();
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+  }
+
+  ec = asio::error_code(
+      static_cast<int>(::ERR_get_error()),
+      asio::error::get_ssl_category());
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_certificate_chain_file(const std::string& filename)
+{
+  asio::error_code ec;
+  use_certificate_chain_file(filename, ec);
+  asio::detail::throw_error(ec, "use_certificate_chain_file");
+}
+
+ASIO_SYNC_OP_VOID context::use_certificate_chain_file(
+    const std::string& filename, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  if (::SSL_CTX_use_certificate_chain_file(handle_, filename.c_str()) != 1)
+  {
+    ec = asio::error_code(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_private_key(
+    const const_buffer& private_key, context::file_format format)
+{
+  asio::error_code ec;
+  use_private_key(private_key, format, ec);
+  asio::detail::throw_error(ec, "use_private_key");
+}
+
+ASIO_SYNC_OP_VOID context::use_private_key(
+    const const_buffer& private_key, context::file_format format,
+    asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+    pem_password_cb* callback = ::SSL_CTX_get_default_passwd_cb(handle_);
+    void* cb_userdata = ::SSL_CTX_get_default_passwd_cb_userdata(handle_);
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+    pem_password_cb* callback = handle_->default_passwd_callback;
+    void* cb_userdata = handle_->default_passwd_callback_userdata;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+
+  bio_cleanup bio = { make_buffer_bio(private_key) };
+  if (bio.p)
+  {
+    evp_pkey_cleanup evp_private_key = { 0 };
+    switch (format)
+    {
+    case context_base::asn1:
+      evp_private_key.p = ::d2i_PrivateKey_bio(bio.p, 0);
+      break;
+    case context_base::pem:
+      evp_private_key.p = ::PEM_read_bio_PrivateKey(
+          bio.p, 0, callback,
+          cb_userdata);
+      break;
+    default:
+      {
+        ec = asio::error::invalid_argument;
+        ASIO_SYNC_OP_VOID_RETURN(ec);
+      }
+    }
+
+    if (evp_private_key.p)
+    {
+      if (::SSL_CTX_use_PrivateKey(handle_, evp_private_key.p) == 1)
+      {
+        ec = asio::error_code();
+        ASIO_SYNC_OP_VOID_RETURN(ec);
+      }
+    }
+  }
+
+  ec = asio::error_code(
+      static_cast<int>(::ERR_get_error()),
+      asio::error::get_ssl_category());
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_private_key_file(
+    const std::string& filename, context::file_format format)
+{
+  asio::error_code ec;
+  use_private_key_file(filename, format, ec);
+  asio::detail::throw_error(ec, "use_private_key_file");
+}
+
+void context::use_rsa_private_key(
+    const const_buffer& private_key, context::file_format format)
+{
+  asio::error_code ec;
+  use_rsa_private_key(private_key, format, ec);
+  asio::detail::throw_error(ec, "use_rsa_private_key");
+}
+
+ASIO_SYNC_OP_VOID context::use_rsa_private_key(
+    const const_buffer& private_key, context::file_format format,
+    asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+    pem_password_cb* callback = ::SSL_CTX_get_default_passwd_cb(handle_);
+    void* cb_userdata = ::SSL_CTX_get_default_passwd_cb_userdata(handle_);
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+    pem_password_cb* callback = handle_->default_passwd_callback;
+    void* cb_userdata = handle_->default_passwd_callback_userdata;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+
+  bio_cleanup bio = { make_buffer_bio(private_key) };
+  if (bio.p)
+  {
+    rsa_cleanup rsa_private_key = { 0 };
+    switch (format)
+    {
+    case context_base::asn1:
+      rsa_private_key.p = ::d2i_RSAPrivateKey_bio(bio.p, 0);
+      break;
+    case context_base::pem:
+      rsa_private_key.p = ::PEM_read_bio_RSAPrivateKey(
+          bio.p, 0, callback,
+          cb_userdata);
+      break;
+    default:
+      {
+        ec = asio::error::invalid_argument;
+        ASIO_SYNC_OP_VOID_RETURN(ec);
+      }
+    }
+
+    if (rsa_private_key.p)
+    {
+      if (::SSL_CTX_use_RSAPrivateKey(handle_, rsa_private_key.p) == 1)
+      {
+        ec = asio::error_code();
+        ASIO_SYNC_OP_VOID_RETURN(ec);
+      }
+    }
+  }
+
+  ec = asio::error_code(
+      static_cast<int>(::ERR_get_error()),
+      asio::error::get_ssl_category());
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID context::use_private_key_file(
+    const std::string& filename, context::file_format format,
+    asio::error_code& ec)
+{
+  int file_type;
+  switch (format)
+  {
+  case context_base::asn1:
+    file_type = SSL_FILETYPE_ASN1;
+    break;
+  case context_base::pem:
+    file_type = SSL_FILETYPE_PEM;
+    break;
+  default:
+    {
+      ec = asio::error::invalid_argument;
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+  }
+
+  ::ERR_clear_error();
+
+  if (::SSL_CTX_use_PrivateKey_file(handle_, filename.c_str(), file_type) != 1)
+  {
+    ec = asio::error_code(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_rsa_private_key_file(
+    const std::string& filename, context::file_format format)
+{
+  asio::error_code ec;
+  use_rsa_private_key_file(filename, format, ec);
+  asio::detail::throw_error(ec, "use_rsa_private_key_file");
+}
+
+ASIO_SYNC_OP_VOID context::use_rsa_private_key_file(
+    const std::string& filename, context::file_format format,
+    asio::error_code& ec)
+{
+  int file_type;
+  switch (format)
+  {
+  case context_base::asn1:
+    file_type = SSL_FILETYPE_ASN1;
+    break;
+  case context_base::pem:
+    file_type = SSL_FILETYPE_PEM;
+    break;
+  default:
+    {
+      ec = asio::error::invalid_argument;
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+  }
+
+  ::ERR_clear_error();
+
+  if (::SSL_CTX_use_RSAPrivateKey_file(
+        handle_, filename.c_str(), file_type) != 1)
+  {
+    ec = asio::error_code(
+        static_cast<int>(::ERR_get_error()),
+        asio::error::get_ssl_category());
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_tmp_dh(const const_buffer& dh)
+{
+  asio::error_code ec;
+  use_tmp_dh(dh, ec);
+  asio::detail::throw_error(ec, "use_tmp_dh");
+}
+
+ASIO_SYNC_OP_VOID context::use_tmp_dh(
+    const const_buffer& dh, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  bio_cleanup bio = { make_buffer_bio(dh) };
+  if (bio.p)
+  {
+    return do_use_tmp_dh(bio.p, ec);
+  }
+
+  ec = asio::error_code(
+      static_cast<int>(::ERR_get_error()),
+      asio::error::get_ssl_category());
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+void context::use_tmp_dh_file(const std::string& filename)
+{
+  asio::error_code ec;
+  use_tmp_dh_file(filename, ec);
+  asio::detail::throw_error(ec, "use_tmp_dh_file");
+}
+
+ASIO_SYNC_OP_VOID context::use_tmp_dh_file(
+    const std::string& filename, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  bio_cleanup bio = { ::BIO_new_file(filename.c_str(), "r") };
+  if (bio.p)
+  {
+    return do_use_tmp_dh(bio.p, ec);
+  }
+
+  ec = asio::error_code(
+      static_cast<int>(::ERR_get_error()),
+      asio::error::get_ssl_category());
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID context::do_use_tmp_dh(
+    BIO* bio, asio::error_code& ec)
+{
+  ::ERR_clear_error();
+
+  dh_cleanup dh = { ::PEM_read_bio_DHparams(bio, 0, 0, 0) };
+  if (dh.p)
+  {
+    if (::SSL_CTX_set_tmp_dh(handle_, dh.p) == 1)
+    {
+      ec = asio::error_code();
+      ASIO_SYNC_OP_VOID_RETURN(ec);
+    }
+  }
+
+  ec = asio::error_code(
+      static_cast<int>(::ERR_get_error()),
+      asio::error::get_ssl_category());
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+ASIO_SYNC_OP_VOID context::do_set_verify_callback(
+    detail::verify_callback_base* callback, asio::error_code& ec)
+{
+  if (SSL_CTX_get_app_data(handle_))
+  {
+    delete static_cast<detail::verify_callback_base*>(
+        SSL_CTX_get_app_data(handle_));
+  }
+
+  SSL_CTX_set_app_data(handle_, callback);
+
+  ::SSL_CTX_set_verify(handle_,
+      ::SSL_CTX_get_verify_mode(handle_),
+      &context::verify_callback_function);
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+int context::verify_callback_function(int preverified, X509_STORE_CTX* ctx)
+{
+  if (ctx)
+  {
+    if (SSL* ssl = static_cast<SSL*>(
+          ::X509_STORE_CTX_get_ex_data(
+            ctx, ::SSL_get_ex_data_X509_STORE_CTX_idx())))
+    {
+      if (SSL_CTX* handle = ::SSL_get_SSL_CTX(ssl))
+      {
+        if (SSL_CTX_get_app_data(handle))
+        {
+          detail::verify_callback_base* callback =
+            static_cast<detail::verify_callback_base*>(
+                SSL_CTX_get_app_data(handle));
+
+          verify_context verify_ctx(ctx);
+          return callback->call(preverified != 0, verify_ctx) ? 1 : 0;
+        }
+      }
+    }
+  }
+
+  return 0;
+}
+
+ASIO_SYNC_OP_VOID context::do_set_password_callback(
+    detail::password_callback_base* callback, asio::error_code& ec)
+{
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
+  void* old_callback = ::SSL_CTX_get_default_passwd_cb_userdata(handle_);
+  ::SSL_CTX_set_default_passwd_cb_userdata(handle_, callback);
+#else // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+  void* old_callback = handle_->default_passwd_callback_userdata;
+  handle_->default_passwd_callback_userdata = callback;
+#endif // (OPENSSL_VERSION_NUMBER >= 0x10100000L)
+
+  if (old_callback)
+    delete static_cast<detail::password_callback_base*>(
+        old_callback);
+
+  SSL_CTX_set_default_passwd_cb(handle_, &context::password_callback_function);
+
+  ec = asio::error_code();
+  ASIO_SYNC_OP_VOID_RETURN(ec);
+}
+
+int context::password_callback_function(
+    char* buf, int size, int purpose, void* data)
+{
+  using namespace std; // For strncat and strlen.
+
+  if (data)
+  {
+    detail::password_callback_base* callback =
+      static_cast<detail::password_callback_base*>(data);
+
+    std::string passwd = callback->call(static_cast<std::size_t>(size),
+        purpose ? context_base::for_writing : context_base::for_reading);
+
+#if defined(ASIO_HAS_SECURE_RTL)
+    strcpy_s(buf, size, passwd.c_str());
+#else // defined(ASIO_HAS_SECURE_RTL)
+    *buf = '\0';
+    if (size > 0)
+      strncat(buf, passwd.c_str(), size - 1);
+#endif // defined(ASIO_HAS_SECURE_RTL)
+
+    return static_cast<int>(strlen(buf));
+  }
+
+  return 0;
+}
+
+BIO* context::make_buffer_bio(const const_buffer& b)
+{
+  return ::BIO_new_mem_buf(
+      const_cast<void*>(b.data()),
+      static_cast<int>(b.size()));
+}
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_IMPL_CONTEXT_IPP
diff --git a/subprojects/asio/include/asio/ssl/impl/error.ipp b/subprojects/asio/include/asio/ssl/impl/error.ipp
new file mode 100644
index 000000000..98e8c91b4
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/impl/error.ipp
@@ -0,0 +1,100 @@
+//
+// ssl/impl/error.ipp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_IMPL_ERROR_IPP
+#define ASIO_SSL_IMPL_ERROR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ssl/error.hpp"
+#include "asio/ssl/detail/openssl_init.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace error {
+namespace detail {
+
+class ssl_category : public asio::error_category
+{
+public:
+  const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT
+  {
+    return "asio.ssl";
+  }
+
+  std::string message(int value) const
+  {
+    const char* s = ::ERR_reason_error_string(value);
+    return s ? s : "asio.ssl error";
+  }
+};
+
+} // namespace detail
+
+const asio::error_category& get_ssl_category()
+{
+  static detail::ssl_category instance;
+  return instance;
+}
+
+} // namespace error
+namespace ssl {
+namespace error {
+
+#if (OPENSSL_VERSION_NUMBER < 0x10100000L) && !defined(OPENSSL_IS_BORINGSSL)
+
+const asio::error_category& get_stream_category()
+{
+  return asio::error::get_ssl_category();
+}
+
+#else
+
+namespace detail {
+
+class stream_category : public asio::error_category
+{
+public:
+  const char* name() const ASIO_ERROR_CATEGORY_NOEXCEPT
+  {
+    return "asio.ssl.stream";
+  }
+
+  std::string message(int value) const
+  {
+    switch (value)
+    {
+    case stream_truncated: return "stream truncated";
+    default: return "asio.ssl.stream error";
+    }
+  }
+};
+
+} // namespace detail
+
+const asio::error_category& get_stream_category()
+{
+  static detail::stream_category instance;
+  return instance;
+}
+
+#endif
+
+} // namespace error
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_IMPL_ERROR_IPP
diff --git a/subprojects/asio/include/asio/ssl/impl/rfc2818_verification.ipp b/subprojects/asio/include/asio/ssl/impl/rfc2818_verification.ipp
new file mode 100644
index 000000000..577e4a12e
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/impl/rfc2818_verification.ipp
@@ -0,0 +1,160 @@
+//
+// ssl/impl/rfc2818_verification.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_IMPL_RFC2818_VERIFICATION_IPP
+#define ASIO_SSL_IMPL_RFC2818_VERIFICATION_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <cctype>
+#include <cstring>
+#include "asio/ip/address.hpp"
+#include "asio/ssl/rfc2818_verification.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+bool rfc2818_verification::operator()(
+    bool preverified, verify_context& ctx) const
+{
+  using namespace std; // For memcmp.
+
+  // Don't bother looking at certificates that have failed pre-verification.
+  if (!preverified)
+    return false;
+
+  // We're only interested in checking the certificate at the end of the chain.
+  int depth = X509_STORE_CTX_get_error_depth(ctx.native_handle());
+  if (depth > 0)
+    return true;
+
+  // Try converting the host name to an address. If it is an address then we
+  // need to look for an IP address in the certificate rather than a host name.
+  asio::error_code ec;
+  ip::address address = ip::make_address(host_, ec);
+  bool is_address = !ec;
+
+  X509* cert = X509_STORE_CTX_get_current_cert(ctx.native_handle());
+
+  // Go through the alternate names in the certificate looking for matching DNS
+  // or IP address entries.
+  GENERAL_NAMES* gens = static_cast<GENERAL_NAMES*>(
+      X509_get_ext_d2i(cert, NID_subject_alt_name, 0, 0));
+  for (int i = 0; i < sk_GENERAL_NAME_num(gens); ++i)
+  {
+    GENERAL_NAME* gen = sk_GENERAL_NAME_value(gens, i);
+    if (gen->type == GEN_DNS && !is_address)
+    {
+      ASN1_IA5STRING* domain = gen->d.dNSName;
+      if (domain->type == V_ASN1_IA5STRING && domain->data && domain->length)
+      {
+        const char* pattern = reinterpret_cast<const char*>(domain->data);
+        std::size_t pattern_length = domain->length;
+        if (match_pattern(pattern, pattern_length, host_.c_str()))
+        {
+          GENERAL_NAMES_free(gens);
+          return true;
+        }
+      }
+    }
+    else if (gen->type == GEN_IPADD && is_address)
+    {
+      ASN1_OCTET_STRING* ip_address = gen->d.iPAddress;
+      if (ip_address->type == V_ASN1_OCTET_STRING && ip_address->data)
+      {
+        if (address.is_v4() && ip_address->length == 4)
+        {
+          ip::address_v4::bytes_type bytes = address.to_v4().to_bytes();
+          if (memcmp(bytes.data(), ip_address->data, 4) == 0)
+          {
+            GENERAL_NAMES_free(gens);
+            return true;
+          }
+        }
+        else if (address.is_v6() && ip_address->length == 16)
+        {
+          ip::address_v6::bytes_type bytes = address.to_v6().to_bytes();
+          if (memcmp(bytes.data(), ip_address->data, 16) == 0)
+          {
+            GENERAL_NAMES_free(gens);
+            return true;
+          }
+        }
+      }
+    }
+  }
+  GENERAL_NAMES_free(gens);
+
+  // No match in the alternate names, so try the common names. We should only
+  // use the "most specific" common name, which is the last one in the list.
+  X509_NAME* name = X509_get_subject_name(cert);
+  int i = -1;
+  ASN1_STRING* common_name = 0;
+  while ((i = X509_NAME_get_index_by_NID(name, NID_commonName, i)) >= 0)
+  {
+    X509_NAME_ENTRY* name_entry = X509_NAME_get_entry(name, i);
+    common_name = X509_NAME_ENTRY_get_data(name_entry);
+  }
+  if (common_name && common_name->data && common_name->length)
+  {
+    const char* pattern = reinterpret_cast<const char*>(common_name->data);
+    std::size_t pattern_length = common_name->length;
+    if (match_pattern(pattern, pattern_length, host_.c_str()))
+      return true;
+  }
+
+  return false;
+}
+
+bool rfc2818_verification::match_pattern(const char* pattern,
+    std::size_t pattern_length, const char* host)
+{
+  using namespace std; // For tolower.
+
+  const char* p = pattern;
+  const char* p_end = p + pattern_length;
+  const char* h = host;
+
+  while (p != p_end && *h)
+  {
+    if (*p == '*')
+    {
+      ++p;
+      while (*h && *h != '.')
+        if (match_pattern(p, p_end - p, h++))
+          return true;
+    }
+    else if (tolower(*p) == tolower(*h))
+    {
+      ++p;
+      ++h;
+    }
+    else
+    {
+      return false;
+    }
+  }
+
+  return p == p_end && !*h;
+}
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_IMPL_RFC2818_VERIFICATION_IPP
diff --git a/subprojects/asio/include/asio/ssl/impl/src.hpp b/subprojects/asio/include/asio/ssl/impl/src.hpp
new file mode 100644
index 000000000..9a1b038a4
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/impl/src.hpp
@@ -0,0 +1,28 @@
+//
+// impl/ssl/src.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_IMPL_SRC_HPP
+#define ASIO_SSL_IMPL_SRC_HPP
+
+#define ASIO_SOURCE
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# error Do not compile Asio library source with ASIO_HEADER_ONLY defined
+#endif
+
+#include "asio/ssl/impl/context.ipp"
+#include "asio/ssl/impl/error.ipp"
+#include "asio/ssl/detail/impl/engine.ipp"
+#include "asio/ssl/detail/impl/openssl_init.ipp"
+#include "asio/ssl/impl/rfc2818_verification.ipp"
+
+#endif // ASIO_SSL_IMPL_SRC_HPP
diff --git a/subprojects/asio/include/asio/ssl/rfc2818_verification.hpp b/subprojects/asio/include/asio/ssl/rfc2818_verification.hpp
new file mode 100644
index 000000000..3589f5383
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/rfc2818_verification.hpp
@@ -0,0 +1,94 @@
+//
+// ssl/rfc2818_verification.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_RFC2818_VERIFICATION_HPP
+#define ASIO_SSL_RFC2818_VERIFICATION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include <string>
+#include "asio/ssl/detail/openssl_types.hpp"
+#include "asio/ssl/verify_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+/// Verifies a certificate against a hostname according to the rules described
+/// in RFC 2818.
+/**
+ * @par Example
+ * The following example shows how to synchronously open a secure connection to
+ * a given host name:
+ * @code
+ * using asio::ip::tcp;
+ * namespace ssl = asio::ssl;
+ * typedef ssl::stream<tcp::socket> ssl_socket;
+ *
+ * // Create a context that uses the default paths for finding CA certificates.
+ * ssl::context ctx(ssl::context::sslv23);
+ * ctx.set_default_verify_paths();
+ *
+ * // Open a socket and connect it to the remote host.
+ * asio::io_context io_context;
+ * ssl_socket sock(io_context, ctx);
+ * tcp::resolver resolver(io_context);
+ * tcp::resolver::query query("host.name", "https");
+ * asio::connect(sock.lowest_layer(), resolver.resolve(query));
+ * sock.lowest_layer().set_option(tcp::no_delay(true));
+ *
+ * // Perform SSL handshake and verify the remote host's certificate.
+ * sock.set_verify_mode(ssl::verify_peer);
+ * sock.set_verify_callback(ssl::rfc2818_verification("host.name"));
+ * sock.handshake(ssl_socket::client);
+ *
+ * // ... read and write as normal ...
+ * @endcode
+ */
+class rfc2818_verification
+{
+public:
+  /// The type of the function object's result.
+  typedef bool result_type;
+
+  /// Constructor.
+  explicit rfc2818_verification(const std::string& host)
+    : host_(host)
+  {
+  }
+
+  /// Perform certificate verification.
+  ASIO_DECL bool operator()(bool preverified, verify_context& ctx) const;
+
+private:
+  // Helper function to check a host name against a pattern.
+  ASIO_DECL static bool match_pattern(const char* pattern,
+      std::size_t pattern_length, const char* host);
+
+  // Helper function to check a host name against an IPv4 address
+  // The host name to be checked.
+  std::string host_;
+};
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/ssl/impl/rfc2818_verification.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_SSL_RFC2818_VERIFICATION_HPP
diff --git a/subprojects/asio/include/asio/ssl/stream.hpp b/subprojects/asio/include/asio/ssl/stream.hpp
new file mode 100644
index 000000000..a05ee8834
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/stream.hpp
@@ -0,0 +1,762 @@
+//
+// ssl/stream.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_STREAM_HPP
+#define ASIO_SSL_STREAM_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/async_result.hpp"
+#include "asio/detail/buffer_sequence_adapter.hpp"
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/ssl/context.hpp"
+#include "asio/ssl/detail/buffered_handshake_op.hpp"
+#include "asio/ssl/detail/handshake_op.hpp"
+#include "asio/ssl/detail/io.hpp"
+#include "asio/ssl/detail/read_op.hpp"
+#include "asio/ssl/detail/shutdown_op.hpp"
+#include "asio/ssl/detail/stream_core.hpp"
+#include "asio/ssl/detail/write_op.hpp"
+#include "asio/ssl/stream_base.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+/// Provides stream-oriented functionality using SSL.
+/**
+ * The stream class template provides asynchronous and blocking stream-oriented
+ * functionality using SSL.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe. The application must also ensure that all
+ * asynchronous operations are performed within the same implicit or explicit
+ * strand.
+ *
+ * @par Example
+ * To use the SSL stream template with an ip::tcp::socket, you would write:
+ * @code
+ * asio::io_context io_context;
+ * asio::ssl::context ctx(asio::ssl::context::sslv23);
+ * asio::ssl::stream<asio:ip::tcp::socket> sock(io_context, ctx);
+ * @endcode
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+template <typename Stream>
+class stream :
+  public stream_base,
+  private noncopyable
+{
+public:
+  /// The native handle type of the SSL stream.
+  typedef SSL* native_handle_type;
+
+  /// Structure for use with deprecated impl_type.
+  struct impl_struct
+  {
+    SSL* ssl;
+  };
+
+  /// The type of the next layer.
+  typedef typename remove_reference<Stream>::type next_layer_type;
+
+  /// The type of the lowest layer.
+  typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
+
+  /// The type of the executor associated with the object.
+  typedef typename lowest_layer_type::executor_type executor_type;
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Construct a stream.
+  /**
+   * This constructor creates a stream and initialises the underlying stream
+   * object.
+   *
+   * @param arg The argument to be passed to initialise the underlying stream.
+   *
+   * @param ctx The SSL context to be used for the stream.
+   */
+  template <typename Arg>
+  stream(Arg&& arg, context& ctx)
+    : next_layer_(ASIO_MOVE_CAST(Arg)(arg)),
+      core_(ctx.native_handle(),
+          next_layer_.lowest_layer().get_executor().context())
+  {
+  }
+#else // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  template <typename Arg>
+  stream(Arg& arg, context& ctx)
+    : next_layer_(arg),
+      core_(ctx.native_handle(),
+          next_layer_.lowest_layer().get_executor().context())
+  {
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destructor.
+  /**
+   * @note A @c stream object must not be destroyed while there are pending
+   * asynchronous operations associated with it.
+   */
+  ~stream()
+  {
+  }
+
+  /// Get the executor associated with the object.
+  /**
+   * This function may be used to obtain the executor object that the stream
+   * uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A copy of the executor that stream will use to dispatch handlers.
+   */
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return next_layer_.lowest_layer().get_executor();
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_context()
+  {
+    return next_layer_.lowest_layer().get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  asio::io_context& get_io_service()
+  {
+    return next_layer_.lowest_layer().get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the underlying implementation in the native type.
+  /**
+   * This function may be used to obtain the underlying implementation of the
+   * context. This is intended to allow access to context functionality that is
+   * not otherwise provided.
+   *
+   * @par Example
+   * The native_handle() function returns a pointer of type @c SSL* that is
+   * suitable for passing to functions such as @c SSL_get_verify_result and
+   * @c SSL_get_peer_certificate:
+   * @code
+   * asio::ssl::stream<asio:ip::tcp::socket> sock(io_context, ctx);
+   *
+   * // ... establish connection and perform handshake ...
+   *
+   * if (X509* cert = SSL_get_peer_certificate(sock.native_handle()))
+   * {
+   *   if (SSL_get_verify_result(sock.native_handle()) == X509_V_OK)
+   *   {
+   *     // ...
+   *   }
+   * }
+   * @endcode
+   */
+  native_handle_type native_handle()
+  {
+    return core_.engine_.native_handle();
+  }
+
+  /// Get a reference to the next layer.
+  /**
+   * This function returns a reference to the next layer in a stack of stream
+   * layers.
+   *
+   * @return A reference to the next layer in the stack of stream layers.
+   * Ownership is not transferred to the caller.
+   */
+  const next_layer_type& next_layer() const
+  {
+    return next_layer_;
+  }
+
+  /// Get a reference to the next layer.
+  /**
+   * This function returns a reference to the next layer in a stack of stream
+   * layers.
+   *
+   * @return A reference to the next layer in the stack of stream layers.
+   * Ownership is not transferred to the caller.
+   */
+  next_layer_type& next_layer()
+  {
+    return next_layer_;
+  }
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * stream layers.
+   *
+   * @return A reference to the lowest layer in the stack of stream layers.
+   * Ownership is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return next_layer_.lowest_layer();
+  }
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * stream layers.
+   *
+   * @return A reference to the lowest layer in the stack of stream layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return next_layer_.lowest_layer();
+  }
+
+  /// Set the peer verification mode.
+  /**
+   * This function may be used to configure the peer verification mode used by
+   * the stream. The new mode will override the mode inherited from the context.
+   *
+   * @param v A bitmask of peer verification modes. See @ref verify_mode for
+   * available values.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_set_verify.
+   */
+  void set_verify_mode(verify_mode v)
+  {
+    asio::error_code ec;
+    set_verify_mode(v, ec);
+    asio::detail::throw_error(ec, "set_verify_mode");
+  }
+
+  /// Set the peer verification mode.
+  /**
+   * This function may be used to configure the peer verification mode used by
+   * the stream. The new mode will override the mode inherited from the context.
+   *
+   * @param v A bitmask of peer verification modes. See @ref verify_mode for
+   * available values.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_set_verify.
+   */
+  ASIO_SYNC_OP_VOID set_verify_mode(
+      verify_mode v, asio::error_code& ec)
+  {
+    core_.engine_.set_verify_mode(v, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Set the peer verification depth.
+  /**
+   * This function may be used to configure the maximum verification depth
+   * allowed by the stream.
+   *
+   * @param depth Maximum depth for the certificate chain verification that
+   * shall be allowed.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_set_verify_depth.
+   */
+  void set_verify_depth(int depth)
+  {
+    asio::error_code ec;
+    set_verify_depth(depth, ec);
+    asio::detail::throw_error(ec, "set_verify_depth");
+  }
+
+  /// Set the peer verification depth.
+  /**
+   * This function may be used to configure the maximum verification depth
+   * allowed by the stream.
+   *
+   * @param depth Maximum depth for the certificate chain verification that
+   * shall be allowed.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_set_verify_depth.
+   */
+  ASIO_SYNC_OP_VOID set_verify_depth(
+      int depth, asio::error_code& ec)
+  {
+    core_.engine_.set_verify_depth(depth, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Set the callback used to verify peer certificates.
+  /**
+   * This function is used to specify a callback function that will be called
+   * by the implementation when it needs to verify a peer certificate.
+   *
+   * @param callback The function object to be used for verifying a certificate.
+   * The function signature of the handler must be:
+   * @code bool verify_callback(
+   *   bool preverified, // True if the certificate passed pre-verification.
+   *   verify_context& ctx // The peer certificate and other context.
+   * ); @endcode
+   * The return value of the callback is true if the certificate has passed
+   * verification, false otherwise.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note Calls @c SSL_set_verify.
+   */
+  template <typename VerifyCallback>
+  void set_verify_callback(VerifyCallback callback)
+  {
+    asio::error_code ec;
+    this->set_verify_callback(callback, ec);
+    asio::detail::throw_error(ec, "set_verify_callback");
+  }
+
+  /// Set the callback used to verify peer certificates.
+  /**
+   * This function is used to specify a callback function that will be called
+   * by the implementation when it needs to verify a peer certificate.
+   *
+   * @param callback The function object to be used for verifying a certificate.
+   * The function signature of the handler must be:
+   * @code bool verify_callback(
+   *   bool preverified, // True if the certificate passed pre-verification.
+   *   verify_context& ctx // The peer certificate and other context.
+   * ); @endcode
+   * The return value of the callback is true if the certificate has passed
+   * verification, false otherwise.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @note Calls @c SSL_set_verify.
+   */
+  template <typename VerifyCallback>
+  ASIO_SYNC_OP_VOID set_verify_callback(VerifyCallback callback,
+      asio::error_code& ec)
+  {
+    core_.engine_.set_verify_callback(
+        new detail::verify_callback<VerifyCallback>(callback), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform SSL handshaking.
+  /**
+   * This function is used to perform SSL handshaking on the stream. The
+   * function call will block until handshaking is complete or an error occurs.
+   *
+   * @param type The type of handshaking to be performed, i.e. as a client or as
+   * a server.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void handshake(handshake_type type)
+  {
+    asio::error_code ec;
+    handshake(type, ec);
+    asio::detail::throw_error(ec, "handshake");
+  }
+
+  /// Perform SSL handshaking.
+  /**
+   * This function is used to perform SSL handshaking on the stream. The
+   * function call will block until handshaking is complete or an error occurs.
+   *
+   * @param type The type of handshaking to be performed, i.e. as a client or as
+   * a server.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID handshake(handshake_type type,
+      asio::error_code& ec)
+  {
+    detail::io(next_layer_, core_, detail::handshake_op(type), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform SSL handshaking.
+  /**
+   * This function is used to perform SSL handshaking on the stream. The
+   * function call will block until handshaking is complete or an error occurs.
+   *
+   * @param type The type of handshaking to be performed, i.e. as a client or as
+   * a server.
+   *
+   * @param buffers The buffered data to be reused for the handshake.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  template <typename ConstBufferSequence>
+  void handshake(handshake_type type, const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    handshake(type, buffers, ec);
+    asio::detail::throw_error(ec, "handshake");
+  }
+
+  /// Perform SSL handshaking.
+  /**
+   * This function is used to perform SSL handshaking on the stream. The
+   * function call will block until handshaking is complete or an error occurs.
+   *
+   * @param type The type of handshaking to be performed, i.e. as a client or as
+   * a server.
+   *
+   * @param buffers The buffered data to be reused for the handshake.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  template <typename ConstBufferSequence>
+  ASIO_SYNC_OP_VOID handshake(handshake_type type,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    detail::io(next_layer_, core_,
+        detail::buffered_handshake_op<ConstBufferSequence>(type, buffers), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous SSL handshake.
+  /**
+   * This function is used to asynchronously perform an SSL handshake on the
+   * stream. This function call always returns immediately.
+   *
+   * @param type The type of handshaking to be performed, i.e. as a client or as
+   * a server.
+   *
+   * @param handler The handler to be called when the handshake operation
+   * completes. Copies will be made of the handler as required. The equivalent
+   * function signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   */
+  template <typename HandshakeHandler>
+  ASIO_INITFN_RESULT_TYPE(HandshakeHandler,
+      void (asio::error_code))
+  async_handshake(handshake_type type,
+      ASIO_MOVE_ARG(HandshakeHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a HandshakeHandler.
+    ASIO_HANDSHAKE_HANDLER_CHECK(HandshakeHandler, handler) type_check;
+
+    asio::async_completion<HandshakeHandler,
+      void (asio::error_code)> init(handler);
+
+    detail::async_io(next_layer_, core_,
+        detail::handshake_op(type), init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Start an asynchronous SSL handshake.
+  /**
+   * This function is used to asynchronously perform an SSL handshake on the
+   * stream. This function call always returns immediately.
+   *
+   * @param type The type of handshaking to be performed, i.e. as a client or as
+   * a server.
+   *
+   * @param buffers The buffered data to be reused for the handshake. Although
+   * the buffers object may be copied as necessary, ownership of the underlying
+   * buffers is retained by the caller, which must guarantee that they remain
+   * valid until the handler is called.
+   *
+   * @param handler The handler to be called when the handshake operation
+   * completes. Copies will be made of the handler as required. The equivalent
+   * function signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred // Amount of buffers used in handshake.
+   * ); @endcode
+   */
+  template <typename ConstBufferSequence, typename BufferedHandshakeHandler>
+  ASIO_INITFN_RESULT_TYPE(BufferedHandshakeHandler,
+      void (asio::error_code, std::size_t))
+  async_handshake(handshake_type type, const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(BufferedHandshakeHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a BufferedHandshakeHandler.
+    ASIO_BUFFERED_HANDSHAKE_HANDLER_CHECK(
+        BufferedHandshakeHandler, handler) type_check;
+
+    asio::async_completion<BufferedHandshakeHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    detail::async_io(next_layer_, core_,
+        detail::buffered_handshake_op<ConstBufferSequence>(type, buffers),
+        init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Shut down SSL on the stream.
+  /**
+   * This function is used to shut down SSL on the stream. The function call
+   * will block until SSL has been shut down or an error occurs.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void shutdown()
+  {
+    asio::error_code ec;
+    shutdown(ec);
+    asio::detail::throw_error(ec, "shutdown");
+  }
+
+  /// Shut down SSL on the stream.
+  /**
+   * This function is used to shut down SSL on the stream. The function call
+   * will block until SSL has been shut down or an error occurs.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID shutdown(asio::error_code& ec)
+  {
+    detail::io(next_layer_, core_, detail::shutdown_op(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously shut down SSL on the stream.
+  /**
+   * This function is used to asynchronously shut down SSL on the stream. This
+   * function call always returns immediately.
+   *
+   * @param handler The handler to be called when the handshake operation
+   * completes. Copies will be made of the handler as required. The equivalent
+   * function signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   */
+  template <typename ShutdownHandler>
+  ASIO_INITFN_RESULT_TYPE(ShutdownHandler,
+      void (asio::error_code))
+  async_shutdown(ASIO_MOVE_ARG(ShutdownHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ShutdownHandler.
+    ASIO_SHUTDOWN_HANDLER_CHECK(ShutdownHandler, handler) type_check;
+
+    asio::async_completion<ShutdownHandler,
+      void (asio::error_code)> init(handler);
+
+    detail::async_io(next_layer_, core_, detail::shutdown_op(),
+        init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Write some data to the stream.
+  /**
+   * This function is used to write data on the stream. The function call will
+   * block until one or more bytes of data has been written successfully, or
+   * until an error occurs.
+   *
+   * @param buffers The data to be written.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that all
+   * data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t n = write_some(buffers, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return n;
+  }
+
+  /// Write some data to the stream.
+  /**
+   * This function is used to write data on the stream. The function call will
+   * block until one or more bytes of data has been written successfully, or
+   * until an error occurs.
+   *
+   * @param buffers The data to be written to the stream.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that all
+   * data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return detail::io(next_layer_, core_,
+        detail::write_op<ConstBufferSequence>(buffers), ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write one or more bytes of data to
+   * the stream. The function call always returns immediately.
+   *
+   * @param buffers The data to be written to the stream. Although the buffers
+   * object may be copied as necessary, ownership of the underlying buffers is
+   * retained by the caller, which must guarantee that they remain valid until
+   * the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The equivalent function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   *
+   * @note The async_write_some operation may not transmit all of the data to
+   * the peer. Consider using the @ref async_write function if you need to
+   * ensure that all data is written before the asynchronous operation
+   * completes.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    asio::async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    detail::async_io(next_layer_, core_,
+        detail::write_op<ConstBufferSequence>(buffers),
+        init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the stream.
+  /**
+   * This function is used to read data from the stream. The function call will
+   * block until one or more bytes of data has been read successfully, or until
+   * an error occurs.
+   *
+   * @param buffers The buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that the
+   * requested amount of data is read before the blocking operation completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t n = read_some(buffers, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return n;
+  }
+
+  /// Read some data from the stream.
+  /**
+   * This function is used to read data from the stream. The function call will
+   * block until one or more bytes of data has been read successfully, or until
+   * an error occurs.
+   *
+   * @param buffers The buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that the
+   * requested amount of data is read before the blocking operation completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return detail::io(next_layer_, core_,
+        detail::read_op<MutableBufferSequence>(buffers), ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read one or more bytes of data from
+   * the stream. The function call always returns immediately.
+   *
+   * @param buffers The buffers into which the data will be read. Although the
+   * buffers object may be copied as necessary, ownership of the underlying
+   * buffers is retained by the caller, which must guarantee that they remain
+   * valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The equivalent function
+   * signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   *
+   * @note The async_read_some operation may not read all of the requested
+   * number of bytes. Consider using the @ref async_read function if you need to
+   * ensure that the requested amount of data is read before the asynchronous
+   * operation completes.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    asio::async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    detail::async_io(next_layer_, core_,
+        detail::read_op<MutableBufferSequence>(buffers),
+        init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  Stream next_layer_;
+  detail::stream_core core_;
+};
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_STREAM_HPP
diff --git a/subprojects/asio/include/asio/ssl/stream_base.hpp b/subprojects/asio/include/asio/ssl/stream_base.hpp
new file mode 100644
index 000000000..56873e4a5
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/stream_base.hpp
@@ -0,0 +1,52 @@
+//
+// ssl/stream_base.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_STREAM_BASE_HPP
+#define ASIO_SSL_STREAM_BASE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+/// The stream_base class is used as a base for the asio::ssl::stream
+/// class template so that we have a common place to define various enums.
+class stream_base
+{
+public:
+  /// Different handshake types.
+  enum handshake_type
+  {
+    /// Perform handshaking as a client.
+    client,
+
+    /// Perform handshaking as a server.
+    server
+  };
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~stream_base()
+  {
+  }
+};
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_STREAM_BASE_HPP
diff --git a/subprojects/asio/include/asio/ssl/verify_context.hpp b/subprojects/asio/include/asio/ssl/verify_context.hpp
new file mode 100644
index 000000000..e17269715
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/verify_context.hpp
@@ -0,0 +1,67 @@
+//
+// ssl/verify_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_VERIFY_CONTEXT_HPP
+#define ASIO_SSL_VERIFY_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+/// A simple wrapper around the X509_STORE_CTX type, used during verification of
+/// a peer certificate.
+/**
+ * @note The verify_context does not own the underlying X509_STORE_CTX object.
+ */
+class verify_context
+  : private noncopyable
+{
+public:
+  /// The native handle type of the verification context.
+  typedef X509_STORE_CTX* native_handle_type;
+
+  /// Constructor.
+  explicit verify_context(native_handle_type handle)
+    : handle_(handle)
+  {
+  }
+
+  /// Get the underlying implementation in the native type.
+  /**
+   * This function may be used to obtain the underlying implementation of the
+   * context. This is intended to allow access to context functionality that is
+   * not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return handle_;
+  }
+
+private:
+  // The underlying native implementation.
+  native_handle_type handle_;
+};
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_VERIFY_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/ssl/verify_mode.hpp b/subprojects/asio/include/asio/ssl/verify_mode.hpp
new file mode 100644
index 000000000..8c4b39426
--- /dev/null
+++ b/subprojects/asio/include/asio/ssl/verify_mode.hpp
@@ -0,0 +1,63 @@
+//
+// ssl/verify_mode.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SSL_VERIFY_MODE_HPP
+#define ASIO_SSL_VERIFY_MODE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/ssl/detail/openssl_types.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace ssl {
+
+/// Bitmask type for peer verification.
+/**
+ * Possible values are:
+ *
+ * @li @ref verify_none
+ * @li @ref verify_peer
+ * @li @ref verify_fail_if_no_peer_cert
+ * @li @ref verify_client_once
+ */
+typedef int verify_mode;
+
+#if defined(GENERATING_DOCUMENTATION)
+/// No verification.
+const int verify_none = implementation_defined;
+
+/// Verify the peer.
+const int verify_peer = implementation_defined;
+
+/// Fail verification if the peer has no certificate. Ignored unless
+/// @ref verify_peer is set.
+const int verify_fail_if_no_peer_cert = implementation_defined;
+
+/// Do not request client certificate on renegotiation. Ignored unless
+/// @ref verify_peer is set.
+const int verify_client_once = implementation_defined;
+#else
+const int verify_none = SSL_VERIFY_NONE;
+const int verify_peer = SSL_VERIFY_PEER;
+const int verify_fail_if_no_peer_cert = SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
+const int verify_client_once = SSL_VERIFY_CLIENT_ONCE;
+#endif
+
+} // namespace ssl
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SSL_VERIFY_MODE_HPP
diff --git a/subprojects/asio/include/asio/steady_timer.hpp b/subprojects/asio/include/asio/steady_timer.hpp
new file mode 100644
index 000000000..3ede20847
--- /dev/null
+++ b/subprojects/asio/include/asio/steady_timer.hpp
@@ -0,0 +1,42 @@
+//
+// steady_timer.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_STEADY_TIMER_HPP
+#define ASIO_STEADY_TIMER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_waitable_timer.hpp"
+#include "asio/detail/chrono.hpp"
+
+namespace asio {
+
+/// Typedef for a timer based on the steady clock.
+/**
+ * This typedef uses the C++11 @c &lt;chrono&gt; standard library facility, if
+ * available. Otherwise, it may use the Boost.Chrono library. To explicitly
+ * utilise Boost.Chrono, use the basic_waitable_timer template directly:
+ * @code
+ * typedef basic_waitable_timer<boost::chrono::steady_clock> timer;
+ * @endcode
+ */
+typedef basic_waitable_timer<chrono::steady_clock> steady_timer;
+
+} // namespace asio
+
+#endif // defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_STEADY_TIMER_HPP
diff --git a/subprojects/asio/include/asio/strand.hpp b/subprojects/asio/include/asio/strand.hpp
new file mode 100644
index 000000000..ea78ef02f
--- /dev/null
+++ b/subprojects/asio/include/asio/strand.hpp
@@ -0,0 +1,286 @@
+//
+// strand.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_STRAND_HPP
+#define ASIO_STRAND_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/strand_executor_service.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Provides serialised function invocation for any executor type.
+template <typename Executor>
+class strand
+{
+public:
+  /// The type of the underlying executor.
+  typedef Executor inner_executor_type;
+
+  /// Default constructor.
+  /**
+   * This constructor is only valid if the underlying executor type is default
+   * constructible.
+   */
+  strand()
+    : executor_(),
+      impl_(use_service<detail::strand_executor_service>(
+            executor_.context()).create_implementation())
+  {
+  }
+
+  /// Construct a strand for the specified executor.
+  explicit strand(const Executor& e)
+    : executor_(e),
+      impl_(use_service<detail::strand_executor_service>(
+            executor_.context()).create_implementation())
+  {
+  }
+
+  /// Copy constructor.
+  strand(const strand& other) ASIO_NOEXCEPT
+    : executor_(other.executor_),
+      impl_(other.impl_)
+  {
+  }
+
+  /// Converting constructor.
+  /**
+   * This constructor is only valid if the @c OtherExecutor type is convertible
+   * to @c Executor.
+   */
+  template <class OtherExecutor>
+  strand(
+      const strand<OtherExecutor>& other) ASIO_NOEXCEPT
+    : executor_(other.executor_),
+      impl_(other.impl_)
+  {
+  }
+
+  /// Assignment operator.
+  strand& operator=(const strand& other) ASIO_NOEXCEPT
+  {
+    executor_ = other.executor_;
+    impl_ = other.impl_;
+    return *this;
+  }
+
+  /// Converting assignment operator.
+  /**
+   * This assignment operator is only valid if the @c OtherExecutor type is
+   * convertible to @c Executor.
+   */
+  template <class OtherExecutor>
+  strand& operator=(
+      const strand<OtherExecutor>& other) ASIO_NOEXCEPT
+  {
+    executor_ = other.executor_;
+    impl_ = other.impl_;
+    return *this;
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move constructor.
+  strand(strand&& other) ASIO_NOEXCEPT
+    : executor_(ASIO_MOVE_CAST(Executor)(other.executor_)),
+      impl_(ASIO_MOVE_CAST(implementation_type)(other.impl_))
+  {
+  }
+
+  /// Converting move constructor.
+  /**
+   * This constructor is only valid if the @c OtherExecutor type is convertible
+   * to @c Executor.
+   */
+  template <class OtherExecutor>
+  strand(strand<OtherExecutor>&& other) ASIO_NOEXCEPT
+    : executor_(ASIO_MOVE_CAST(OtherExecutor)(other)),
+      impl_(ASIO_MOVE_CAST(implementation_type)(other.impl_))
+  {
+  }
+
+  /// Move assignment operator.
+  strand& operator=(strand&& other) ASIO_NOEXCEPT
+  {
+    executor_ = ASIO_MOVE_CAST(Executor)(other);
+    impl_ = ASIO_MOVE_CAST(implementation_type)(other.impl_);
+    return *this;
+  }
+
+  /// Converting move assignment operator.
+  /**
+   * This assignment operator is only valid if the @c OtherExecutor type is
+   * convertible to @c Executor.
+   */
+  template <class OtherExecutor>
+  strand& operator=(
+      const strand<OtherExecutor>&& other) ASIO_NOEXCEPT
+  {
+    executor_ = ASIO_MOVE_CAST(OtherExecutor)(other);
+    impl_ = ASIO_MOVE_CAST(implementation_type)(other.impl_);
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destructor.
+  ~strand()
+  {
+  }
+
+  /// Obtain the underlying executor.
+  inner_executor_type get_inner_executor() const ASIO_NOEXCEPT
+  {
+    return executor_;
+  }
+
+  /// Obtain the underlying execution context.
+  execution_context& context() const ASIO_NOEXCEPT
+  {
+    return executor_.context();
+  }
+
+  /// Inform the strand that it has some outstanding work to do.
+  /**
+   * The strand delegates this call to its underlying executor.
+   */
+  void on_work_started() const ASIO_NOEXCEPT
+  {
+    executor_.on_work_started();
+  }
+
+  /// Inform the strand that some work is no longer outstanding.
+  /**
+   * The strand delegates this call to its underlying executor.
+   */
+  void on_work_finished() const ASIO_NOEXCEPT
+  {
+    executor_.on_work_finished();
+  }
+
+  /// Request the strand to invoke the given function object.
+  /**
+   * This function is used to ask the strand to execute the given function
+   * object on its underlying executor. The function object will be executed
+   * inside this function if the strand is not otherwise busy and if the
+   * underlying executor's @c dispatch() function is also able to execute the
+   * function before returning.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+  {
+    detail::strand_executor_service::dispatch(impl_,
+        executor_, ASIO_MOVE_CAST(Function)(f), a);
+  }
+
+  /// Request the strand to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object will never be executed inside this function.
+   * Instead, it will be scheduled by the underlying executor's defer function.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+  {
+    detail::strand_executor_service::post(impl_,
+        executor_, ASIO_MOVE_CAST(Function)(f), a);
+  }
+
+  /// Request the strand to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object will never be executed inside this function.
+   * Instead, it will be scheduled by the underlying executor's defer function.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const
+  {
+    detail::strand_executor_service::defer(impl_,
+        executor_, ASIO_MOVE_CAST(Function)(f), a);
+  }
+
+  /// Determine whether the strand is running in the current thread.
+  /**
+   * @return @c true if the current thread is executing a function that was
+   * submitted to the strand using post(), dispatch() or defer(). Otherwise
+   * returns @c false.
+   */
+  bool running_in_this_thread() const ASIO_NOEXCEPT
+  {
+    return detail::strand_executor_service::running_in_this_thread(impl_);
+  }
+
+  /// Compare two strands for equality.
+  /**
+   * Two strands are equal if they refer to the same ordered, non-concurrent
+   * state.
+   */
+  friend bool operator==(const strand& a, const strand& b) ASIO_NOEXCEPT
+  {
+    return a.impl_ == b.impl_;
+  }
+
+  /// Compare two strands for inequality.
+  /**
+   * Two strands are equal if they refer to the same ordered, non-concurrent
+   * state.
+   */
+  friend bool operator!=(const strand& a, const strand& b) ASIO_NOEXCEPT
+  {
+    return a.impl_ != b.impl_;
+  }
+
+private:
+  Executor executor_;
+  typedef detail::strand_executor_service::implementation_type
+    implementation_type;
+  implementation_type impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+// If both io_context.hpp and strand.hpp have been included, automatically
+// include the header file needed for the io_context::strand class.
+#if !defined(ASIO_NO_EXTENSIONS)
+# if defined(ASIO_IO_CONTEXT_HPP)
+#  include "asio/io_context_strand.hpp"
+# endif // defined(ASIO_IO_CONTEXT_HPP)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#endif // ASIO_STRAND_HPP
diff --git a/subprojects/asio/include/asio/stream_socket_service.hpp b/subprojects/asio/include/asio/stream_socket_service.hpp
new file mode 100644
index 000000000..91b0a711f
--- /dev/null
+++ b/subprojects/asio/include/asio/stream_socket_service.hpp
@@ -0,0 +1,412 @@
+//
+// stream_socket_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_STREAM_SOCKET_SERVICE_HPP
+#define ASIO_STREAM_SOCKET_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_WINDOWS_RUNTIME)
+# include "asio/detail/winrt_ssocket_service.hpp"
+#elif defined(ASIO_HAS_IOCP)
+# include "asio/detail/win_iocp_socket_service.hpp"
+#else
+# include "asio/detail/reactive_socket_service.hpp"
+#endif
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a stream socket.
+template <typename Protocol>
+class stream_socket_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<stream_socket_service<Protocol> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The protocol type.
+  typedef Protocol protocol_type;
+
+  /// The endpoint type.
+  typedef typename Protocol::endpoint endpoint_type;
+
+private:
+  // The type of the platform-specific implementation.
+#if defined(ASIO_WINDOWS_RUNTIME)
+  typedef detail::winrt_ssocket_service<Protocol> service_impl_type;
+#elif defined(ASIO_HAS_IOCP)
+  typedef detail::win_iocp_socket_service<Protocol> service_impl_type;
+#else
+  typedef detail::reactive_socket_service<Protocol> service_impl_type;
+#endif
+
+public:
+  /// The type of a stream socket implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native socket type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef typename service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new stream socket service for the specified io_context.
+  explicit stream_socket_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        stream_socket_service<Protocol> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new stream socket implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new stream socket implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another stream socket implementation.
+  void move_assign(implementation_type& impl,
+      stream_socket_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+
+  // All socket services have access to each other's implementations.
+  template <typename Protocol1> friend class stream_socket_service;
+
+  /// Move-construct a new stream socket implementation from another protocol
+  /// type.
+  template <typename Protocol1>
+  void converting_move_construct(implementation_type& impl,
+      stream_socket_service<Protocol1>& other_service,
+      typename stream_socket_service<
+        Protocol1>::implementation_type& other_impl,
+      typename enable_if<is_convertible<
+        Protocol1, Protocol>::value>::type* = 0)
+  {
+    service_impl_.template converting_move_construct<Protocol1>(
+        impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a stream socket implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Open a stream socket.
+  ASIO_SYNC_OP_VOID open(implementation_type& impl,
+      const protocol_type& protocol, asio::error_code& ec)
+  {
+    if (protocol.type() == ASIO_OS_DEF(SOCK_STREAM))
+      service_impl_.open(impl, protocol, ec);
+    else
+      ec = asio::error::invalid_argument;
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Assign an existing native socket to a stream socket.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const protocol_type& protocol, const native_handle_type& native_socket,
+      asio::error_code& ec)
+  {
+    service_impl_.assign(impl, protocol, native_socket, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a stream socket implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Release ownership of the underlying socket.
+  native_handle_type release(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return service_impl_.release(impl, ec);
+  }
+
+  /// Get the native socket implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the socket.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the socket is at the out-of-band data mark.
+  bool at_mark(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.at_mark(impl, ec);
+  }
+
+  /// Determine the number of bytes available for reading.
+  std::size_t available(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.available(impl, ec);
+  }
+
+  /// Bind the stream socket to the specified local endpoint.
+  ASIO_SYNC_OP_VOID bind(implementation_type& impl,
+      const endpoint_type& endpoint, asio::error_code& ec)
+  {
+    service_impl_.bind(impl, endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Connect the stream socket to the specified endpoint.
+  ASIO_SYNC_OP_VOID connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint, asio::error_code& ec)
+  {
+    service_impl_.connect(impl, peer_endpoint, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Start an asynchronous connect.
+  template <typename ConnectHandler>
+  ASIO_INITFN_RESULT_TYPE(ConnectHandler,
+      void (asio::error_code))
+  async_connect(implementation_type& impl,
+      const endpoint_type& peer_endpoint,
+      ASIO_MOVE_ARG(ConnectHandler) handler)
+  {
+    async_completion<ConnectHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_connect(impl, peer_endpoint, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Set a socket option.
+  template <typename SettableSocketOption>
+  ASIO_SYNC_OP_VOID set_option(implementation_type& impl,
+      const SettableSocketOption& option, asio::error_code& ec)
+  {
+    service_impl_.set_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get a socket option.
+  template <typename GettableSocketOption>
+  ASIO_SYNC_OP_VOID get_option(const implementation_type& impl,
+      GettableSocketOption& option, asio::error_code& ec) const
+  {
+    service_impl_.get_option(impl, option, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform an IO control command on the socket.
+  template <typename IoControlCommand>
+  ASIO_SYNC_OP_VOID io_control(implementation_type& impl,
+      IoControlCommand& command, asio::error_code& ec)
+  {
+    service_impl_.io_control(impl, command, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the socket.
+  bool non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the socket.
+  ASIO_SYNC_OP_VOID non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Gets the non-blocking mode of the native socket implementation.
+  bool native_non_blocking(const implementation_type& impl) const
+  {
+    return service_impl_.native_non_blocking(impl);
+  }
+
+  /// Sets the non-blocking mode of the native socket implementation.
+  ASIO_SYNC_OP_VOID native_non_blocking(implementation_type& impl,
+      bool mode, asio::error_code& ec)
+  {
+    service_impl_.native_non_blocking(impl, mode, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the local endpoint.
+  endpoint_type local_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.local_endpoint(impl, ec);
+  }
+
+  /// Get the remote endpoint.
+  endpoint_type remote_endpoint(const implementation_type& impl,
+      asio::error_code& ec) const
+  {
+    return service_impl_.remote_endpoint(impl, ec);
+  }
+
+  /// Disable sends or receives on the socket.
+  ASIO_SYNC_OP_VOID shutdown(implementation_type& impl,
+      socket_base::shutdown_type what, asio::error_code& ec)
+  {
+    service_impl_.shutdown(impl, what, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Wait for the socket to become ready to read, ready to write, or to have
+  /// pending error conditions.
+  ASIO_SYNC_OP_VOID wait(implementation_type& impl,
+      socket_base::wait_type w, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, w, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Asynchronously wait for the socket to become ready to read, ready to
+  /// write, or to have pending error conditions.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl, socket_base::wait_type w,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, w, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Send the given data to the peer.
+  template <typename ConstBufferSequence>
+  std::size_t send(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.send(impl, buffers, flags, ec);
+  }
+
+  /// Start an asynchronous send.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_send(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_send(impl, buffers, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Receive some data from the peer.
+  template <typename MutableBufferSequence>
+  std::size_t receive(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags, asio::error_code& ec)
+  {
+    return service_impl_.receive(impl, buffers, flags, ec);
+  }
+
+  /// Start an asynchronous receive.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_receive(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      socket_base::message_flags flags,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_receive(impl, buffers, flags, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_STREAM_SOCKET_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/streambuf.hpp b/subprojects/asio/include/asio/streambuf.hpp
new file mode 100644
index 000000000..cb3f35f7d
--- /dev/null
+++ b/subprojects/asio/include/asio/streambuf.hpp
@@ -0,0 +1,33 @@
+//
+// streambuf.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_STREAMBUF_HPP
+#define ASIO_STREAMBUF_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_NO_IOSTREAM)
+
+#include "asio/basic_streambuf.hpp"
+
+namespace asio {
+
+/// Typedef for the typical usage of basic_streambuf.
+typedef basic_streambuf<> streambuf;
+
+} // namespace asio
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+
+#endif // ASIO_STREAMBUF_HPP
diff --git a/subprojects/asio/include/asio/system_context.hpp b/subprojects/asio/include/asio/system_context.hpp
new file mode 100644
index 000000000..ccd111343
--- /dev/null
+++ b/subprojects/asio/include/asio/system_context.hpp
@@ -0,0 +1,78 @@
+//
+// system_context.hpp
+// ~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SYSTEM_CONTEXT_HPP
+#define ASIO_SYSTEM_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/scheduler.hpp"
+#include "asio/detail/thread_group.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class system_executor;
+
+/// The executor context for the system executor.
+class system_context : public execution_context
+{
+public:
+  /// The executor type associated with the context.
+  typedef system_executor executor_type;
+
+  /// Destructor shuts down all threads in the system thread pool.
+  ASIO_DECL ~system_context();
+
+  /// Obtain an executor for the context.
+  executor_type get_executor() ASIO_NOEXCEPT;
+
+  /// Signal all threads in the system thread pool to stop.
+  ASIO_DECL void stop();
+
+  /// Determine whether the system thread pool has been stopped.
+  ASIO_DECL bool stopped() const ASIO_NOEXCEPT;
+
+  /// Join all threads in the system thread pool.
+  ASIO_DECL void join();
+
+#if defined(GENERATING_DOCUMENTATION)
+private:
+#endif // defined(GENERATING_DOCUMENTATION)
+  // Constructor creates all threads in the system thread pool.
+  ASIO_DECL system_context();
+
+private:
+  friend class system_executor;
+
+  struct thread_function;
+
+  // The underlying scheduler.
+  detail::scheduler& scheduler_;
+
+  // The threads in the system thread pool.
+  detail::thread_group threads_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/system_context.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/system_context.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_SYSTEM_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/system_error.hpp b/subprojects/asio/include/asio/system_error.hpp
new file mode 100644
index 000000000..639089416
--- /dev/null
+++ b/subprojects/asio/include/asio/system_error.hpp
@@ -0,0 +1,131 @@
+//
+// system_error.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SYSTEM_ERROR_HPP
+#define ASIO_SYSTEM_ERROR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_STD_SYSTEM_ERROR)
+# include <system_error>
+#else // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+# include <cerrno>
+# include <exception>
+# include <string>
+# include "asio/error_code.hpp"
+# include "asio/detail/scoped_ptr.hpp"
+#endif // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+#if defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+typedef std::system_error system_error;
+
+#else // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+/// The system_error class is used to represent system conditions that
+/// prevent the library from operating correctly.
+class system_error
+  : public std::exception
+{
+public:
+  /// Construct with an error code.
+  system_error(const error_code& ec)
+    : code_(ec),
+      context_()
+  {
+  }
+
+  /// Construct with an error code and context.
+  system_error(const error_code& ec, const std::string& context)
+    : code_(ec),
+      context_(context)
+  {
+  }
+
+  /// Copy constructor.
+  system_error(const system_error& other)
+    : std::exception(other),
+      code_(other.code_),
+      context_(other.context_),
+      what_()
+  {
+  }
+
+  /// Destructor.
+  virtual ~system_error() throw ()
+  {
+  }
+
+  /// Assignment operator.
+  system_error& operator=(const system_error& e)
+  {
+    context_ = e.context_;
+    code_ = e.code_;
+    what_.reset();
+    return *this;
+  }
+
+  /// Get a string representation of the exception.
+  virtual const char* what() const throw ()
+  {
+#if !defined(ASIO_NO_EXCEPTIONS)
+    try
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+    {
+      if (!what_.get())
+      {
+        std::string tmp(context_);
+        if (tmp.length())
+          tmp += ": ";
+        tmp += code_.message();
+        what_.reset(new std::string(tmp));
+      }
+      return what_->c_str();
+    }
+#if !defined(ASIO_NO_EXCEPTIONS)
+    catch (std::exception&)
+    {
+      return "system_error";
+    }
+#endif // !defined(ASIO_NO_EXCEPTIONS)
+  }
+
+  /// Get the error code associated with the exception.
+  error_code code() const
+  {
+    return code_;
+  }
+
+private:
+  // The code associated with the error.
+  error_code code_;
+
+  // The context associated with the error.
+  std::string context_;
+
+  // The string representation of the error.
+  mutable asio::detail::scoped_ptr<std::string> what_;
+};
+
+#endif // defined(ASIO_HAS_STD_SYSTEM_ERROR)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_SYSTEM_ERROR_HPP
diff --git a/subprojects/asio/include/asio/system_executor.hpp b/subprojects/asio/include/asio/system_executor.hpp
new file mode 100644
index 000000000..b588a21b4
--- /dev/null
+++ b/subprojects/asio/include/asio/system_executor.hpp
@@ -0,0 +1,129 @@
+//
+// system_executor.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SYSTEM_EXECUTOR_HPP
+#define ASIO_SYSTEM_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class system_context;
+
+/// An executor that uses arbitrary threads.
+/**
+ * The system executor represents an execution context where functions are
+ * permitted to run on arbitrary threads. The post() and defer() functions
+ * schedule the function to run on an unspecified system thread pool, and
+ * dispatch() invokes the function immediately.
+ */
+class system_executor
+{
+public:
+  /// Obtain the underlying execution context.
+  system_context& context() const ASIO_NOEXCEPT;
+
+  /// Inform the executor that it has some outstanding work to do.
+  /**
+   * For the system executor, this is a no-op.
+   */
+  void on_work_started() const ASIO_NOEXCEPT
+  {
+  }
+
+  /// Inform the executor that some work is no longer outstanding.
+  /**
+   * For the system executor, this is a no-op.
+   */
+  void on_work_finished() const ASIO_NOEXCEPT
+  {
+  }
+
+  /// Request the system executor to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object will always be executed inside this function.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the system executor to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object will never be executed inside this function.
+   * Instead, it will be scheduled to run on an unspecified system thread pool.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the system executor to invoke the given function object.
+  /**
+   * This function is used to ask the executor to execute the given function
+   * object. The function object will never be executed inside this function.
+   * Instead, it will be scheduled to run on an unspecified system thread pool.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Compare two executors for equality.
+  /**
+   * System executors always compare equal.
+   */
+  friend bool operator==(const system_executor&,
+      const system_executor&) ASIO_NOEXCEPT
+  {
+    return true;
+  }
+
+  /// Compare two executors for inequality.
+  /**
+   * System executors always compare equal.
+   */
+  friend bool operator!=(const system_executor&,
+      const system_executor&) ASIO_NOEXCEPT
+  {
+    return false;
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/system_executor.hpp"
+
+#endif // ASIO_SYSTEM_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/system_timer.hpp b/subprojects/asio/include/asio/system_timer.hpp
new file mode 100644
index 000000000..e75e7d4c1
--- /dev/null
+++ b/subprojects/asio/include/asio/system_timer.hpp
@@ -0,0 +1,42 @@
+//
+// system_timer.hpp
+// ~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_SYSTEM_TIMER_HPP
+#define ASIO_SYSTEM_TIMER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_waitable_timer.hpp"
+#include "asio/detail/chrono.hpp"
+
+namespace asio {
+
+/// Typedef for a timer based on the system clock.
+/**
+ * This typedef uses the C++11 @c &lt;chrono&gt; standard library facility, if
+ * available. Otherwise, it may use the Boost.Chrono library. To explicitly
+ * utilise Boost.Chrono, use the basic_waitable_timer template directly:
+ * @code
+ * typedef basic_waitable_timer<boost::chrono::system_clock> timer;
+ * @endcode
+ */
+typedef basic_waitable_timer<chrono::system_clock> system_timer;
+
+} // namespace asio
+
+#endif // defined(ASIO_HAS_CHRONO) || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_SYSTEM_TIMER_HPP
diff --git a/subprojects/asio/include/asio/thread.hpp b/subprojects/asio/include/asio/thread.hpp
new file mode 100644
index 000000000..eeeef7bb5
--- /dev/null
+++ b/subprojects/asio/include/asio/thread.hpp
@@ -0,0 +1,92 @@
+//
+// thread.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_THREAD_HPP
+#define ASIO_THREAD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/thread.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// A simple abstraction for starting threads.
+/**
+ * The asio::thread class implements the smallest possible subset of the
+ * functionality of boost::thread. It is intended to be used only for starting
+ * a thread and waiting for it to exit. If more extensive threading
+ * capabilities are required, you are strongly advised to use something else.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Example
+ * A typical use of asio::thread would be to launch a thread to run an
+ * io_context's event processing loop:
+ *
+ * @par
+ * @code asio::io_context io_context;
+ * // ...
+ * asio::thread t(boost::bind(&asio::io_context::run, &io_context));
+ * // ...
+ * t.join(); @endcode
+ */
+class thread
+  : private noncopyable
+{
+public:
+  /// Start a new thread that executes the supplied function.
+  /**
+   * This constructor creates a new thread that will execute the given function
+   * or function object.
+   *
+   * @param f The function or function object to be run in the thread. The
+   * function signature must be: @code void f(); @endcode
+   */
+  template <typename Function>
+  explicit thread(Function f)
+    : impl_(f)
+  {
+  }
+
+  /// Destructor.
+  ~thread()
+  {
+  }
+
+  /// Wait for the thread to exit.
+  /**
+   * This function will block until the thread has exited.
+   *
+   * If this function is not called before the thread object is destroyed, the
+   * thread itself will continue to run until completion. You will, however,
+   * no longer have the ability to wait for it to exit.
+   */
+  void join()
+  {
+    impl_.join();
+  }
+
+private:
+  detail::thread impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_THREAD_HPP
diff --git a/subprojects/asio/include/asio/thread_pool.hpp b/subprojects/asio/include/asio/thread_pool.hpp
new file mode 100644
index 000000000..1a86bcd5b
--- /dev/null
+++ b/subprojects/asio/include/asio/thread_pool.hpp
@@ -0,0 +1,232 @@
+//
+// thread_pool.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_THREAD_POOL_HPP
+#define ASIO_THREAD_POOL_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/scheduler.hpp"
+#include "asio/detail/thread_group.hpp"
+#include "asio/execution_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// A simple fixed-size thread pool.
+/**
+ * The thread pool class is an execution context where functions are permitted
+ * to run on one of a fixed number of threads.
+ *
+ * @par Submitting tasks to the pool
+ *
+ * To submit functions to the thread_pool, use the @ref asio::dispatch,
+ * @ref asio::post or @ref asio::defer free functions.
+ *
+ * For example:
+ *
+ * @code void my_task()
+ * {
+ *   ...
+ * }
+ *
+ * ...
+ *
+ * // Launch the pool with four threads.
+ * asio::thread_pool pool(4);
+ *
+ * // Submit a function to the pool.
+ * asio::post(pool, my_task);
+ *
+ * // Submit a lambda object to the pool.
+ * asio::post(pool,
+ *     []()
+ *     {
+ *       ...
+ *     });
+ *
+ * // Wait for all tasks in the pool to complete.
+ * pool.join(); @endcode
+ */
+class thread_pool
+  : public execution_context
+{
+public:
+  class executor_type;
+
+  /// Constructs a pool with an automatically determined number of threads.
+  ASIO_DECL thread_pool();
+
+  /// Constructs a pool with a specified number of threads.
+  ASIO_DECL thread_pool(std::size_t num_threads);
+
+  /// Destructor.
+  /**
+   * Automatically stops and joins the pool, if not explicitly done beforehand.
+   */
+  ASIO_DECL ~thread_pool();
+
+  /// Obtains the executor associated with the pool.
+  executor_type get_executor() ASIO_NOEXCEPT;
+
+  /// Stops the threads.
+  /**
+   * This function stops the threads as soon as possible. As a result of calling
+   * @c stop(), pending function objects may be never be invoked.
+   */
+  ASIO_DECL void stop();
+
+  /// Joins the threads.
+  /**
+   * This function blocks until the threads in the pool have completed. If @c
+   * stop() is not called prior to @c join(), the @c join() call will wait
+   * until the pool has no more outstanding work.
+   */
+  ASIO_DECL void join();
+
+private:
+  friend class executor_type;
+  struct thread_function;
+
+  // The underlying scheduler.
+  detail::scheduler& scheduler_;
+
+  // The threads in the pool.
+  detail::thread_group threads_;
+};
+
+/// Executor used to submit functions to a thread pool.
+class thread_pool::executor_type
+{
+public:
+  /// Obtain the underlying execution context.
+  thread_pool& context() const ASIO_NOEXCEPT;
+
+  /// Inform the thread pool that it has some outstanding work to do.
+  /**
+   * This function is used to inform the thread pool that some work has begun.
+   * This ensures that the thread pool's join() function will not return while
+   * the work is underway.
+   */
+  void on_work_started() const ASIO_NOEXCEPT;
+
+  /// Inform the thread pool that some work is no longer outstanding.
+  /**
+   * This function is used to inform the thread pool that some work has
+   * finished. Once the count of unfinished work reaches zero, the thread
+   * pool's join() function is permitted to exit.
+   */
+  void on_work_finished() const ASIO_NOEXCEPT;
+
+  /// Request the thread pool to invoke the given function object.
+  /**
+   * This function is used to ask the thread pool to execute the given function
+   * object. If the current thread belongs to the pool, @c dispatch() executes
+   * the function before returning. Otherwise, the function will be scheduled
+   * to run on the thread pool.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the thread pool to invoke the given function object.
+  /**
+   * This function is used to ask the thread pool to execute the given function
+   * object. The function object will never be executed inside @c post().
+   * Instead, it will be scheduled to run on the thread pool.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Request the thread pool to invoke the given function object.
+  /**
+   * This function is used to ask the thread pool to execute the given function
+   * object. The function object will never be executed inside @c defer().
+   * Instead, it will be scheduled to run on the thread pool.
+   *
+   * If the current thread belongs to the thread pool, @c defer() will delay
+   * scheduling the function object until the current thread returns control to
+   * the pool.
+   *
+   * @param f The function object to be called. The executor will make
+   * a copy of the handler object as required. The function signature of the
+   * function object must be: @code void function(); @endcode
+   *
+   * @param a An allocator that may be used by the executor to allocate the
+   * internal storage needed for function invocation.
+   */
+  template <typename Function, typename Allocator>
+  void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
+
+  /// Determine whether the thread pool is running in the current thread.
+  /**
+   * @return @c true if the current thread belongs to the pool. Otherwise
+   * returns @c false.
+   */
+  bool running_in_this_thread() const ASIO_NOEXCEPT;
+
+  /// Compare two executors for equality.
+  /**
+   * Two executors are equal if they refer to the same underlying thread pool.
+   */
+  friend bool operator==(const executor_type& a,
+      const executor_type& b) ASIO_NOEXCEPT
+  {
+    return &a.pool_ == &b.pool_;
+  }
+
+  /// Compare two executors for inequality.
+  /**
+   * Two executors are equal if they refer to the same underlying thread pool.
+   */
+  friend bool operator!=(const executor_type& a,
+      const executor_type& b) ASIO_NOEXCEPT
+  {
+    return &a.pool_ != &b.pool_;
+  }
+
+private:
+  friend class thread_pool;
+
+  // Constructor.
+  explicit executor_type(thread_pool& p) : pool_(p) {}
+
+  // The underlying thread pool.
+  thread_pool& pool_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/thread_pool.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/thread_pool.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_THREAD_POOL_HPP
diff --git a/subprojects/asio/include/asio/time_traits.hpp b/subprojects/asio/include/asio/time_traits.hpp
new file mode 100644
index 000000000..72f4aabe7
--- /dev/null
+++ b/subprojects/asio/include/asio/time_traits.hpp
@@ -0,0 +1,86 @@
+//
+// time_traits.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TIME_TRAITS_HPP
+#define ASIO_TIME_TRAITS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/socket_types.hpp" // Must come before posix_time.
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <boost/date_time/posix_time/posix_time_types.hpp>
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Time traits suitable for use with the deadline timer.
+template <typename Time>
+struct time_traits;
+
+/// Time traits specialised for posix_time.
+template <>
+struct time_traits<boost::posix_time::ptime>
+{
+  /// The time type.
+  typedef boost::posix_time::ptime time_type;
+
+  /// The duration type.
+  typedef boost::posix_time::time_duration duration_type;
+
+  /// Get the current time.
+  static time_type now()
+  {
+#if defined(BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK)
+    return boost::posix_time::microsec_clock::universal_time();
+#else // defined(BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK)
+    return boost::posix_time::second_clock::universal_time();
+#endif // defined(BOOST_DATE_TIME_HAS_HIGH_PRECISION_CLOCK)
+  }
+
+  /// Add a duration to a time.
+  static time_type add(const time_type& t, const duration_type& d)
+  {
+    return t + d;
+  }
+
+  /// Subtract one time from another.
+  static duration_type subtract(const time_type& t1, const time_type& t2)
+  {
+    return t1 - t2;
+  }
+
+  /// Test whether one time is less than another.
+  static bool less_than(const time_type& t1, const time_type& t2)
+  {
+    return t1 < t2;
+  }
+
+  /// Convert to POSIX duration type.
+  static boost::posix_time::time_duration to_posix_duration(
+      const duration_type& d)
+  {
+    return d;
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+       // || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_TIME_TRAITS_HPP
diff --git a/subprojects/asio/include/asio/ts/buffer.hpp b/subprojects/asio/include/asio/ts/buffer.hpp
new file mode 100644
index 000000000..faf08a474
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/buffer.hpp
@@ -0,0 +1,24 @@
+//
+// ts/buffer.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_BUFFER_HPP
+#define ASIO_TS_BUFFER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/buffer.hpp"
+#include "asio/completion_condition.hpp"
+#include "asio/read.hpp"
+#include "asio/write.hpp"
+#include "asio/read_until.hpp"
+
+#endif // ASIO_TS_BUFFER_HPP
diff --git a/subprojects/asio/include/asio/ts/executor.hpp b/subprojects/asio/include/asio/ts/executor.hpp
new file mode 100644
index 000000000..8669cb6c5
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/executor.hpp
@@ -0,0 +1,35 @@
+//
+// ts/executor.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_EXECUTOR_HPP
+#define ASIO_TS_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/handler_type.hpp"
+#include "asio/async_result.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/execution_context.hpp"
+#include "asio/is_executor.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/bind_executor.hpp"
+#include "asio/executor_work_guard.hpp"
+#include "asio/system_executor.hpp"
+#include "asio/executor.hpp"
+#include "asio/dispatch.hpp"
+#include "asio/post.hpp"
+#include "asio/defer.hpp"
+#include "asio/strand.hpp"
+#include "asio/packaged_task.hpp"
+#include "asio/use_future.hpp"
+
+#endif // ASIO_TS_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/ts/internet.hpp b/subprojects/asio/include/asio/ts/internet.hpp
new file mode 100644
index 000000000..6282e905a
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/internet.hpp
@@ -0,0 +1,40 @@
+//
+// ts/internet.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_INTERNET_HPP
+#define ASIO_TS_INTERNET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/ip/address.hpp"
+#include "asio/ip/address_v4.hpp"
+#include "asio/ip/address_v4_iterator.hpp"
+#include "asio/ip/address_v4_range.hpp"
+#include "asio/ip/address_v6.hpp"
+#include "asio/ip/address_v6_iterator.hpp"
+#include "asio/ip/address_v6_range.hpp"
+#include "asio/ip/bad_address_cast.hpp"
+#include "asio/ip/basic_endpoint.hpp"
+#include "asio/ip/basic_resolver_query.hpp"
+#include "asio/ip/basic_resolver_entry.hpp"
+#include "asio/ip/basic_resolver_iterator.hpp"
+#include "asio/ip/basic_resolver.hpp"
+#include "asio/ip/host_name.hpp"
+#include "asio/ip/network_v4.hpp"
+#include "asio/ip/network_v6.hpp"
+#include "asio/ip/tcp.hpp"
+#include "asio/ip/udp.hpp"
+#include "asio/ip/v6_only.hpp"
+#include "asio/ip/unicast.hpp"
+#include "asio/ip/multicast.hpp"
+
+#endif // ASIO_TS_INTERNET_HPP
diff --git a/subprojects/asio/include/asio/ts/io_context.hpp b/subprojects/asio/include/asio/ts/io_context.hpp
new file mode 100644
index 000000000..b967cd63e
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/io_context.hpp
@@ -0,0 +1,20 @@
+//
+// ts/io_context.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_IO_CONTEXT_HPP
+#define ASIO_TS_IO_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/io_context.hpp"
+
+#endif // ASIO_TS_IO_CONTEXT_HPP
diff --git a/subprojects/asio/include/asio/ts/net.hpp b/subprojects/asio/include/asio/ts/net.hpp
new file mode 100644
index 000000000..f96075d9f
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/net.hpp
@@ -0,0 +1,26 @@
+//
+// ts/net.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_NET_HPP
+#define ASIO_TS_NET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/ts/netfwd.hpp"
+#include "asio/ts/executor.hpp"
+#include "asio/ts/io_context.hpp"
+#include "asio/ts/timer.hpp"
+#include "asio/ts/buffer.hpp"
+#include "asio/ts/socket.hpp"
+#include "asio/ts/internet.hpp"
+
+#endif // ASIO_TS_NET_HPP
diff --git a/subprojects/asio/include/asio/ts/netfwd.hpp b/subprojects/asio/include/asio/ts/netfwd.hpp
new file mode 100644
index 000000000..657a21d37
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/netfwd.hpp
@@ -0,0 +1,197 @@
+//
+// ts/netfwd.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_NETFWD_HPP
+#define ASIO_TS_NETFWD_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_CHRONO)
+# include "asio/detail/chrono.hpp"
+#endif // defined(ASIO_HAS_CHRONO)
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+# include "asio/detail/date_time_fwd.hpp"
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class execution_context;
+
+template <typename T, typename Executor>
+class executor_binder;
+
+template <typename Executor>
+class executor_work_guard;
+
+class system_executor;
+
+class executor;
+
+template <typename Executor>
+class strand;
+
+class io_context;
+
+template <typename Clock>
+struct wait_traits;
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+
+template <typename Time>
+struct time_traits;
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+template <typename Clock, typename WaitTraits>
+class waitable_timer_service;
+
+#if defined(ASIO_HAS_BOOST_DATE_TIME)
+
+template <typename TimeType, typename TimeTraits>
+class deadline_timer_service;
+
+#endif // defined(ASIO_HAS_BOOST_DATE_TIME)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if !defined(ASIO_BASIC_WAITABLE_TIMER_FWD_DECL)
+#define ASIO_BASIC_WAITABLE_TIMER_FWD_DECL
+
+template <typename Clock,
+    typename WaitTraits = asio::wait_traits<Clock>
+    ASIO_SVC_TPARAM_DEF2(= waitable_timer_service<Clock, WaitTraits>)>
+class basic_waitable_timer;
+
+#endif // !defined(ASIO_BASIC_WAITABLE_TIMER_FWD_DECL)
+
+#if defined(ASIO_HAS_CHRONO)
+
+typedef basic_waitable_timer<chrono::system_clock> system_timer;
+
+typedef basic_waitable_timer<chrono::steady_clock> steady_timer;
+
+typedef basic_waitable_timer<chrono::high_resolution_clock>
+  high_resolution_timer;
+
+#endif // defined(ASIO_HAS_CHRONO)
+
+template <class Protocol ASIO_SVC_TPARAM>
+class basic_socket;
+
+template <typename Protocol ASIO_SVC_TPARAM>
+class basic_datagram_socket;
+
+template <typename Protocol ASIO_SVC_TPARAM>
+class basic_stream_socket;
+
+template <typename Protocol ASIO_SVC_TPARAM>
+class basic_socket_acceptor;
+
+#if !defined(ASIO_BASIC_SOCKET_STREAMBUF_FWD_DECL)
+#define ASIO_BASIC_SOCKET_STREAMBUF_FWD_DECL
+
+// Forward declaration with defaulted arguments.
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= stream_socket_service<Protocol>),
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  || defined(GENERATING_DOCUMENTATION)
+    typename Clock = boost::posix_time::ptime,
+    typename WaitTraits = time_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF2(= deadline_timer_service<Clock, WaitTraits>)>
+#else
+    typename Clock = chrono::steady_clock,
+    typename WaitTraits = wait_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF1(= steady_timer::service_type)>
+#endif
+class basic_socket_streambuf;
+
+#endif // !defined(ASIO_BASIC_SOCKET_STREAMBUF_FWD_DECL)
+
+#if !defined(ASIO_BASIC_SOCKET_IOSTREAM_FWD_DECL)
+#define ASIO_BASIC_SOCKET_IOSTREAM_FWD_DECL
+
+// Forward declaration with defaulted arguments.
+template <typename Protocol
+    ASIO_SVC_TPARAM_DEF1(= stream_socket_service<Protocol>),
+#if defined(ASIO_HAS_BOOST_DATE_TIME) \
+  || defined(GENERATING_DOCUMENTATION)
+    typename Clock = boost::posix_time::ptime,
+    typename WaitTraits = time_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF2(= deadline_timer_service<Clock, WaitTraits>)>
+#else
+    typename Clock = chrono::steady_clock,
+    typename WaitTraits = wait_traits<Clock>
+    ASIO_SVC_TPARAM1_DEF1(= steady_timer::service_type)>
+#endif
+class basic_socket_iostream;
+
+#endif // !defined(ASIO_BASIC_SOCKET_IOSTREAM_FWD_DECL)
+
+namespace ip {
+
+class address;
+
+class address_v4;
+
+class address_v6;
+
+template <typename Address>
+class basic_address_iterator;
+
+typedef basic_address_iterator<address_v4> address_v4_iterator;
+
+typedef basic_address_iterator<address_v6> address_v6_iterator;
+
+template <typename Address>
+class basic_address_range;
+
+typedef basic_address_range<address_v4> address_v4_range;
+
+typedef basic_address_range<address_v6> address_v6_range;
+
+class network_v4;
+
+class network_v6;
+
+template <typename InternetProtocol>
+class basic_endpoint;
+
+template <typename InternetProtocol>
+class basic_resolver_entry;
+
+template <typename InternetProtocol>
+class basic_resolver_results;
+
+template <typename InternetProtocol ASIO_SVC_TPARAM>
+class basic_resolver;
+
+class tcp;
+
+class udp;
+
+} // namespace ip
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_TS_NETFWD_HPP
diff --git a/subprojects/asio/include/asio/ts/socket.hpp b/subprojects/asio/include/asio/ts/socket.hpp
new file mode 100644
index 000000000..a54273485
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/socket.hpp
@@ -0,0 +1,27 @@
+//
+// ts/socket.hpp
+// ~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_SOCKET_HPP
+#define ASIO_TS_SOCKET_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/socket_base.hpp"
+#include "asio/basic_socket.hpp"
+#include "asio/basic_datagram_socket.hpp"
+#include "asio/basic_stream_socket.hpp"
+#include "asio/basic_socket_acceptor.hpp"
+#include "asio/basic_socket_streambuf.hpp"
+#include "asio/basic_socket_iostream.hpp"
+#include "asio/connect.hpp"
+
+#endif // ASIO_TS_SOCKET_HPP
diff --git a/subprojects/asio/include/asio/ts/timer.hpp b/subprojects/asio/include/asio/ts/timer.hpp
new file mode 100644
index 000000000..872be8bfd
--- /dev/null
+++ b/subprojects/asio/include/asio/ts/timer.hpp
@@ -0,0 +1,26 @@
+//
+// ts/timer.hpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_TS_TIMER_HPP
+#define ASIO_TS_TIMER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/chrono.hpp"
+
+#include "asio/wait_traits.hpp"
+#include "asio/basic_waitable_timer.hpp"
+#include "asio/system_timer.hpp"
+#include "asio/steady_timer.hpp"
+#include "asio/high_resolution_timer.hpp"
+
+#endif // ASIO_TS_TIMER_HPP
diff --git a/subprojects/asio/include/asio/unyield.hpp b/subprojects/asio/include/asio/unyield.hpp
new file mode 100644
index 000000000..de3ed0275
--- /dev/null
+++ b/subprojects/asio/include/asio/unyield.hpp
@@ -0,0 +1,21 @@
+//
+// unyield.hpp
+// ~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifdef reenter
+# undef reenter
+#endif
+
+#ifdef yield
+# undef yield
+#endif
+
+#ifdef fork
+# undef fork
+#endif
diff --git a/subprojects/asio/include/asio/use_future.hpp b/subprojects/asio/include/asio/use_future.hpp
new file mode 100644
index 000000000..3ac95a562
--- /dev/null
+++ b/subprojects/asio/include/asio/use_future.hpp
@@ -0,0 +1,160 @@
+//
+// use_future.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_USE_FUTURE_HPP
+#define ASIO_USE_FUTURE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/future.hpp"
+
+#if defined(ASIO_HAS_STD_FUTURE_CLASS) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <memory>
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+template <typename Function, typename Allocator>
+class packaged_token;
+
+template <typename Function, typename Allocator, typename Result>
+class packaged_handler;
+
+} // namespace detail
+
+/// Class used to specify that an asynchronous operation should return a future.
+/**
+ * The use_future_t class is used to indicate that an asynchronous operation
+ * should return a std::future object. A use_future_t object may be passed as a
+ * handler to an asynchronous operation, typically using the special value @c
+ * asio::use_future. For example:
+ *
+ * @code std::future<std::size_t> my_future
+ *   = my_socket.async_read_some(my_buffer, asio::use_future); @endcode
+ *
+ * The initiating function (async_read_some in the above example) returns a
+ * future that will receive the result of the operation. If the operation
+ * completes with an error_code indicating failure, it is converted into a
+ * system_error and passed back to the caller via the future.
+ */
+template <typename Allocator = std::allocator<void> >
+class use_future_t
+{
+public:
+  /// The allocator type. The allocator is used when constructing the
+  /// @c std::promise object for a given asynchronous operation.
+  typedef Allocator allocator_type;
+
+  /// Construct using default-constructed allocator.
+  ASIO_CONSTEXPR use_future_t()
+  {
+  }
+
+  /// Construct using specified allocator.
+  explicit use_future_t(const Allocator& allocator)
+    : allocator_(allocator)
+  {
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use rebind().) Specify an alternate allocator.
+  template <typename OtherAllocator>
+  use_future_t<OtherAllocator> operator[](const OtherAllocator& allocator) const
+  {
+    return use_future_t<OtherAllocator>(allocator);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Specify an alternate allocator.
+  template <typename OtherAllocator>
+  use_future_t<OtherAllocator> rebind(const OtherAllocator& allocator) const
+  {
+    return use_future_t<OtherAllocator>(allocator);
+  }
+
+  /// Obtain allocator.
+  allocator_type get_allocator() const
+  {
+    return allocator_;
+  }
+
+  /// Wrap a function object in a packaged task.
+  /**
+   * The @c package function is used to adapt a function object as a packaged
+   * task. When this adapter is passed as a completion token to an asynchronous
+   * operation, the result of the function object is retuned via a std::future.
+   *
+   * @par Example
+   *
+   * @code std::future<std::size_t> fut =
+   *   my_socket.async_read_some(buffer,
+   *     use_future([](asio::error_code ec, std::size_t n)
+   *       {
+   *         return ec ? 0 : n;
+   *       }));
+   * ...
+   * std::size_t n = fut.get(); @endcode
+   */
+  template <typename Function>
+#if defined(GENERATING_DOCUMENTATION)
+  unspecified
+#else // defined(GENERATING_DOCUMENTATION)
+  detail::packaged_token<typename decay<Function>::type, Allocator>
+#endif // defined(GENERATING_DOCUMENTATION)
+  operator()(ASIO_MOVE_ARG(Function) f) const;
+
+private:
+  // Helper type to ensure that use_future can be constexpr default-constructed
+  // even when std::allocator<void> can't be.
+  struct std_allocator_void
+  {
+    ASIO_CONSTEXPR std_allocator_void()
+    {
+    }
+
+    operator std::allocator<void>() const
+    {
+      return std::allocator<void>();
+    }
+  };
+
+  typename conditional<
+    is_same<std::allocator<void>, Allocator>::value,
+    std_allocator_void, Allocator>::type allocator_;
+};
+
+/// A special value, similar to std::nothrow.
+/**
+ * See the documentation for asio::use_future_t for a usage example.
+ */
+#if defined(ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION)
+constexpr use_future_t<> use_future;
+#elif defined(ASIO_MSVC)
+__declspec(selectany) use_future_t<> use_future;
+#endif
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/use_future.hpp"
+
+#endif // defined(ASIO_HAS_STD_FUTURE_CLASS)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_USE_FUTURE_HPP
diff --git a/subprojects/asio/include/asio/uses_executor.hpp b/subprojects/asio/include/asio/uses_executor.hpp
new file mode 100644
index 000000000..e985c2824
--- /dev/null
+++ b/subprojects/asio/include/asio/uses_executor.hpp
@@ -0,0 +1,71 @@
+//
+// uses_executor.hpp
+// ~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_USES_EXECUTOR_HPP
+#define ASIO_USES_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// A special type, similar to std::nothrow_t, used to disambiguate
+/// constructors that accept executor arguments.
+/**
+ * The executor_arg_t struct is an empty structure type used as a unique type
+ * to disambiguate constructor and function overloading. Specifically, some
+ * types have constructors with executor_arg_t as the first argument,
+ * immediately followed by an argument of a type that satisfies the Executor
+ * type requirements.
+ */
+struct executor_arg_t
+{
+  /// Constructor.
+  ASIO_CONSTEXPR executor_arg_t() ASIO_NOEXCEPT
+  {
+  }
+};
+
+/// A special value, similar to std::nothrow, used to disambiguate constructors
+/// that accept executor arguments.
+/**
+ * See asio::executor_arg_t and asio::uses_executor
+ * for more information.
+ */
+#if defined(ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION)
+constexpr executor_arg_t executor_arg;
+#elif defined(ASIO_MSVC)
+__declspec(selectany) executor_arg_t executor_arg;
+#endif
+
+/// The uses_executor trait detects whether a type T has an associated executor
+/// that is convertible from type Executor.
+/**
+ * Meets the BinaryTypeTrait requirements. The Asio library provides a
+ * definition that is derived from false_type. A program may specialize this
+ * template to derive from true_type for a user-defined type T that can be
+ * constructed with an executor, where the first argument of a constructor has
+ * type executor_arg_t and the second argument is convertible from type
+ * Executor.
+ */
+template <typename T, typename Executor>
+struct uses_executor : false_type {};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_USES_EXECUTOR_HPP
diff --git a/subprojects/asio/include/asio/version.hpp b/subprojects/asio/include/asio/version.hpp
new file mode 100644
index 000000000..82ceb1682
--- /dev/null
+++ b/subprojects/asio/include/asio/version.hpp
@@ -0,0 +1,23 @@
+//
+// version.hpp
+// ~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_VERSION_HPP
+#define ASIO_VERSION_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+// ASIO_VERSION % 100 is the sub-minor version
+// ASIO_VERSION / 100 % 1000 is the minor version
+// ASIO_VERSION / 100000 is the major version
+#define ASIO_VERSION 101202 // 1.12.2
+
+#endif // ASIO_VERSION_HPP
diff --git a/subprojects/asio/include/asio/wait_traits.hpp b/subprojects/asio/include/asio/wait_traits.hpp
new file mode 100644
index 000000000..a6016f7c0
--- /dev/null
+++ b/subprojects/asio/include/asio/wait_traits.hpp
@@ -0,0 +1,56 @@
+//
+// wait_traits.hpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WAIT_TRAITS_HPP
+#define ASIO_WAIT_TRAITS_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Wait traits suitable for use with the basic_waitable_timer class template.
+template <typename Clock>
+struct wait_traits
+{
+  /// Convert a clock duration into a duration used for waiting.
+  /**
+   * @returns @c d.
+   */
+  static typename Clock::duration to_wait_duration(
+      const typename Clock::duration& d)
+  {
+    return d;
+  }
+
+  /// Convert a clock duration into a duration used for waiting.
+  /**
+   * @returns @c d.
+   */
+  static typename Clock::duration to_wait_duration(
+      const typename Clock::time_point& t)
+  {
+    typename Clock::time_point now = Clock::now();
+    if (now + (Clock::duration::max)() < t)
+      return (Clock::duration::max)();
+    if (now + (Clock::duration::min)() > t)
+      return (Clock::duration::min)();
+    return t - now;
+  }
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_WAIT_TRAITS_HPP
diff --git a/subprojects/asio/include/asio/waitable_timer_service.hpp b/subprojects/asio/include/asio/waitable_timer_service.hpp
new file mode 100644
index 000000000..75e496f8d
--- /dev/null
+++ b/subprojects/asio/include/asio/waitable_timer_service.hpp
@@ -0,0 +1,210 @@
+//
+// waitable_timer_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WAITABLE_TIMER_SERVICE_HPP
+#define ASIO_WAITABLE_TIMER_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/chrono_time_traits.hpp"
+#include "asio/detail/deadline_timer_service.hpp"
+#include "asio/io_context.hpp"
+#include "asio/wait_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/// Default service implementation for a timer.
+template <typename Clock,
+    typename WaitTraits = asio::wait_traits<Clock> >
+class waitable_timer_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<
+      waitable_timer_service<Clock, WaitTraits> >
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+  /// The clock type.
+  typedef Clock clock_type;
+
+  /// The duration type of the clock.
+  typedef typename clock_type::duration duration;
+
+  /// The time point type of the clock.
+  typedef typename clock_type::time_point time_point;
+
+  /// The wait traits type.
+  typedef WaitTraits traits_type;
+
+private:
+  // The type of the platform-specific implementation.
+  typedef detail::deadline_timer_service<
+    detail::chrono_time_traits<Clock, WaitTraits> > service_impl_type;
+
+public:
+  /// The implementation type of the waitable timer.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef typename service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// Construct a new timer service for the specified io_context.
+  explicit waitable_timer_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        waitable_timer_service<Clock, WaitTraits> >(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new timer implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+  /// Destroy a timer implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new timer implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another timer implementation.
+  void move_assign(implementation_type& impl,
+      waitable_timer_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Cancel any asynchronous wait operations associated with the timer.
+  std::size_t cancel(implementation_type& impl, asio::error_code& ec)
+  {
+    return service_impl_.cancel(impl, ec);
+  }
+
+  /// Cancels one asynchronous wait operation associated with the timer.
+  std::size_t cancel_one(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    return service_impl_.cancel_one(impl, ec);
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use expiry().) Get the expiry time for the timer as an
+  /// absolute time.
+  time_point expires_at(const implementation_type& impl) const
+  {
+    return service_impl_.expiry(impl);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the expiry time for the timer as an absolute time.
+  time_point expiry(const implementation_type& impl) const
+  {
+    return service_impl_.expiry(impl);
+  }
+
+  /// Set the expiry time for the timer as an absolute time.
+  std::size_t expires_at(implementation_type& impl,
+      const time_point& expiry_time, asio::error_code& ec)
+  {
+    return service_impl_.expires_at(impl, expiry_time, ec);
+  }
+
+  /// Set the expiry time for the timer relative to now.
+  std::size_t expires_after(implementation_type& impl,
+      const duration& expiry_time, asio::error_code& ec)
+  {
+    return service_impl_.expires_after(impl, expiry_time, ec);
+  }
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use expiry().) Get the expiry time for the timer relative to
+  /// now.
+  duration expires_from_now(const implementation_type& impl) const
+  {
+    typedef detail::chrono_time_traits<Clock, WaitTraits> traits;
+    return traits::subtract(service_impl_.expiry(impl), traits::now());
+  }
+
+  /// (Deprecated: Use expires_after().) Set the expiry time for the timer
+  /// relative to now.
+  std::size_t expires_from_now(implementation_type& impl,
+      const duration& expiry_time, asio::error_code& ec)
+  {
+    return service_impl_.expires_after(impl, expiry_time, ec);
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  // Perform a blocking wait on the timer.
+  void wait(implementation_type& impl, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, ec);
+  }
+
+  // Start an asynchronous wait on the timer.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WAITABLE_TIMER_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/windows/basic_handle.hpp b/subprojects/asio/include/asio/windows/basic_handle.hpp
new file mode 100644
index 000000000..f7c9d0d03
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/basic_handle.hpp
@@ -0,0 +1,273 @@
+//
+// windows/basic_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_BASIC_HANDLE_HPP
+#define ASIO_WINDOWS_BASIC_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE) \
+  || defined(ASIO_HAS_WINDOWS_STREAM_HANDLE) \
+  || defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Provides Windows handle functionality.
+/**
+ * The windows::basic_handle class template provides the ability to wrap a
+ * Windows handle.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename HandleService>
+class basic_handle
+  : public basic_io_object<HandleService>
+{
+public:
+  /// The native representation of a handle.
+  typedef typename HandleService::native_handle_type native_handle_type;
+
+  /// A basic_handle is always the lowest layer.
+  typedef basic_handle<HandleService> lowest_layer_type;
+
+  /// Construct a basic_handle without opening it.
+  /**
+   * This constructor creates a handle without opening it.
+   *
+   * @param io_context The io_context object that the handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   */
+  explicit basic_handle(asio::io_context& io_context)
+    : basic_io_object<HandleService>(io_context)
+  {
+  }
+
+  /// Construct a basic_handle on an existing native handle.
+  /**
+   * This constructor creates a handle object to hold an existing native handle.
+   *
+   * @param io_context The io_context object that the handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   *
+   * @param handle A native handle.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_handle(asio::io_context& io_context,
+      const native_handle_type& handle)
+    : basic_io_object<HandleService>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_handle from another.
+  /**
+   * This constructor moves a handle from one object to another.
+   *
+   * @param other The other basic_handle object from which the move will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_handle(io_context&) constructor.
+   */
+  basic_handle(basic_handle&& other)
+    : basic_io_object<HandleService>(
+        ASIO_MOVE_CAST(basic_handle)(other))
+  {
+  }
+
+  /// Move-assign a basic_handle from another.
+  /**
+   * This assignment operator moves a handle from one object to another.
+   *
+   * @param other The other basic_handle object from which the move will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_handle(io_context&) constructor.
+   */
+  basic_handle& operator=(basic_handle&& other)
+  {
+    basic_io_object<HandleService>::operator=(
+        ASIO_MOVE_CAST(basic_handle)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since a basic_handle cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since a basic_handle cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+
+  /// Assign an existing native handle to the handle.
+  /*
+   * This function opens the handle to hold an existing native handle.
+   *
+   * @param handle A native handle.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const native_handle_type& handle)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native handle to the handle.
+  /*
+   * This function opens the handle to hold an existing native handle.
+   *
+   * @param handle A native handle.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const native_handle_type& handle,
+      asio::error_code& ec)
+  {
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the handle is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the handle.
+  /**
+   * This function is used to close the handle. Any asynchronous read or write
+   * operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the handle.
+  /**
+   * This function is used to close the handle. Any asynchronous read or write
+   * operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native handle representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * handle. This is intended to allow access to native handle functionality
+   * that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  ~basic_handle()
+  {
+  }
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
+       //   || defined(ASIO_HAS_WINDOWS_STREAM_HANDLE)
+       //   || defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_BASIC_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/basic_object_handle.hpp b/subprojects/asio/include/asio/windows/basic_object_handle.hpp
new file mode 100644
index 000000000..4b2968460
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/basic_object_handle.hpp
@@ -0,0 +1,182 @@
+//
+// windows/basic_object_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2011 Boris Schaeling (boris@highscore.de)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_BASIC_OBJECT_HANDLE_HPP
+#define ASIO_WINDOWS_BASIC_OBJECT_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/windows/basic_handle.hpp"
+#include "asio/windows/object_handle_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Provides object-oriented handle functionality.
+/**
+ * The windows::basic_object_handle class template provides asynchronous and
+ * blocking object-oriented handle functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename ObjectHandleService = object_handle_service>
+class basic_object_handle
+  : public basic_handle<ObjectHandleService>
+{
+public:
+  /// The native representation of a handle.
+  typedef typename ObjectHandleService::native_handle_type native_handle_type;
+
+  /// Construct a basic_object_handle without opening it.
+  /**
+   * This constructor creates an object handle without opening it.
+   *
+   * @param io_context The io_context object that the object handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   */
+  explicit basic_object_handle(asio::io_context& io_context)
+    : basic_handle<ObjectHandleService>(io_context)
+  {
+  }
+
+  /// Construct a basic_object_handle on an existing native handle.
+  /**
+   * This constructor creates an object handle object to hold an existing native
+   * handle.
+   *
+   * @param io_context The io_context object that the object handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   *
+   * @param native_handle The new underlying handle implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_object_handle(asio::io_context& io_context,
+      const native_handle_type& native_handle)
+    : basic_handle<ObjectHandleService>(io_context, native_handle)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_object_handle from another.
+  /**
+   * This constructor moves an object handle from one object to another.
+   *
+   * @param other The other basic_object_handle object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_object_handle(io_context&) constructor.
+   */
+  basic_object_handle(basic_object_handle&& other)
+    : basic_handle<ObjectHandleService>(
+        ASIO_MOVE_CAST(basic_object_handle)(other))
+  {
+  }
+
+  /// Move-assign a basic_object_handle from another.
+  /**
+   * This assignment operator moves an object handle from one object to another.
+   *
+   * @param other The other basic_object_handle object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_object_handle(io_context&) constructor.
+   */
+  basic_object_handle& operator=(basic_object_handle&& other)
+  {
+    basic_handle<ObjectHandleService>::operator=(
+        ASIO_MOVE_CAST(basic_object_handle)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Perform a blocking wait on the object handle.
+  /**
+   * This function is used to wait for the object handle to be set to the
+   * signalled state. This function blocks and does not return until the object
+   * handle has been set to the signalled state.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void wait()
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Perform a blocking wait on the object handle.
+  /**
+   * This function is used to wait for the object handle to be set to the
+   * signalled state. This function blocks and does not return until the object
+   * handle has been set to the signalled state.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  void wait(asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), ec);
+  }
+
+  /// Start an asynchronous wait on the object handle.
+  /**
+   * This function is be used to initiate an asynchronous wait against the
+   * object handle. It always returns immediately.
+   *
+   * @param handler The handler to be called when the object handle is set to
+   * the signalled state. Copies will be made of the handler as required. The
+   * function signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    return this->get_service().async_wait(this->get_implementation(),
+        ASIO_MOVE_CAST(WaitHandler)(handler));
+  }
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_BASIC_OBJECT_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/basic_random_access_handle.hpp b/subprojects/asio/include/asio/windows/basic_random_access_handle.hpp
new file mode 100644
index 000000000..422697731
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/basic_random_access_handle.hpp
@@ -0,0 +1,376 @@
+//
+// windows/basic_random_access_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_BASIC_RANDOM_ACCESS_HANDLE_HPP
+#define ASIO_WINDOWS_BASIC_RANDOM_ACCESS_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/windows/basic_handle.hpp"
+#include "asio/windows/random_access_handle_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Provides random-access handle functionality.
+/**
+ * The windows::basic_random_access_handle class template provides asynchronous
+ * and blocking random-access handle functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+template <typename RandomAccessHandleService = random_access_handle_service>
+class basic_random_access_handle
+  : public basic_handle<RandomAccessHandleService>
+{
+public:
+  /// The native representation of a handle.
+  typedef typename RandomAccessHandleService::native_handle_type
+    native_handle_type;
+
+  /// Construct a basic_random_access_handle without opening it.
+  /**
+   * This constructor creates a random-access handle without opening it. The
+   * handle needs to be opened before data can be written to or read from it.
+   *
+   * @param io_context The io_context object that the random-access handle will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * handle.
+   */
+  explicit basic_random_access_handle(asio::io_context& io_context)
+    : basic_handle<RandomAccessHandleService>(io_context)
+  {
+  }
+
+  /// Construct a basic_random_access_handle on an existing native handle.
+  /**
+   * This constructor creates a random-access handle object to hold an existing
+   * native handle.
+   *
+   * @param io_context The io_context object that the random-access handle will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * handle.
+   *
+   * @param handle The new underlying handle implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_random_access_handle(asio::io_context& io_context,
+      const native_handle_type& handle)
+    : basic_handle<RandomAccessHandleService>(io_context, handle)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_random_access_handle from another.
+  /**
+   * This constructor moves a random-access handle from one object to another.
+   *
+   * @param other The other basic_random_access_handle object from which the
+   * move will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_random_access_handle(io_context&)
+   * constructor.
+   */
+  basic_random_access_handle(basic_random_access_handle&& other)
+    : basic_handle<RandomAccessHandleService>(
+        ASIO_MOVE_CAST(basic_random_access_handle)(other))
+  {
+  }
+
+  /// Move-assign a basic_random_access_handle from another.
+  /**
+   * This assignment operator moves a random-access handle from one object to
+   * another.
+   *
+   * @param other The other basic_random_access_handle object from which the
+   * move will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_random_access_handle(io_context&)
+   * constructor.
+   */
+  basic_random_access_handle& operator=(basic_random_access_handle&& other)
+  {
+    basic_handle<RandomAccessHandleService>::operator=(
+        ASIO_MOVE_CAST(basic_random_access_handle)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Write some data to the handle at the specified offset.
+  /**
+   * This function is used to write data to the random-access handle. The
+   * function call will block until one or more bytes of the data has been
+   * written successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be written.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some_at operation may not write all of the data. Consider
+   * using the @ref write_at function if you need to ensure that all data is
+   * written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.write_some_at(42, asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some_at(uint64_t offset,
+      const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some_at(
+        this->get_implementation(), offset, buffers, ec);
+    asio::detail::throw_error(ec, "write_some_at");
+    return s;
+  }
+
+  /// Write some data to the handle at the specified offset.
+  /**
+   * This function is used to write data to the random-access handle. The
+   * function call will block until one or more bytes of the data has been
+   * written successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be written.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write_at function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some_at(uint64_t offset,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return this->get_service().write_some_at(
+        this->get_implementation(), offset, buffers, ec);
+  }
+
+  /// Start an asynchronous write at the specified offset.
+  /**
+   * This function is used to asynchronously write data to the random-access
+   * handle. The function call always returns immediately.
+   *
+   * @param offset The offset at which the data will be written.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write_at function if you need to ensure that
+   * all data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_write_some_at(42, asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some_at(uint64_t offset,
+      const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    return this->get_service().async_write_some_at(this->get_implementation(),
+        offset, buffers, ASIO_MOVE_CAST(WriteHandler)(handler));
+  }
+
+  /// Read some data from the handle at the specified offset.
+  /**
+   * This function is used to read data from the random-access handle. The
+   * function call will block until one or more bytes of data has been read
+   * successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be read.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read_at function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.read_some_at(42, asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some_at(uint64_t offset,
+      const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some_at(
+        this->get_implementation(), offset, buffers, ec);
+    asio::detail::throw_error(ec, "read_some_at");
+    return s;
+  }
+
+  /// Read some data from the handle at the specified offset.
+  /**
+   * This function is used to read data from the random-access handle. The
+   * function call will block until one or more bytes of data has been read
+   * successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be read.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read_at function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some_at(uint64_t offset,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return this->get_service().read_some_at(
+        this->get_implementation(), offset, buffers, ec);
+  }
+
+  /// Start an asynchronous read at the specified offset.
+  /**
+   * This function is used to asynchronously read data from the random-access
+   * handle. The function call always returns immediately.
+   *
+   * @param offset The offset at which the data will be read.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read_at function if you need to ensure that
+   * the requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_read_some_at(42, asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some_at(uint64_t offset,
+      const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    return this->get_service().async_read_some_at(this->get_implementation(),
+        offset, buffers, ASIO_MOVE_CAST(ReadHandler)(handler));
+  }
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_BASIC_RANDOM_ACCESS_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/basic_stream_handle.hpp b/subprojects/asio/include/asio/windows/basic_stream_handle.hpp
new file mode 100644
index 000000000..3bfce6884
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/basic_stream_handle.hpp
@@ -0,0 +1,359 @@
+//
+// windows/basic_stream_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_BASIC_STREAM_HANDLE_HPP
+#define ASIO_WINDOWS_BASIC_STREAM_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_STREAM_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/detail/handler_type_requirements.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/error.hpp"
+#include "asio/windows/basic_handle.hpp"
+#include "asio/windows/stream_handle_service.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Provides stream-oriented handle functionality.
+/**
+ * The windows::basic_stream_handle class template provides asynchronous and
+ * blocking stream-oriented handle functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+template <typename StreamHandleService = stream_handle_service>
+class basic_stream_handle
+  : public basic_handle<StreamHandleService>
+{
+public:
+  /// The native representation of a handle.
+  typedef typename StreamHandleService::native_handle_type native_handle_type;
+
+  /// Construct a basic_stream_handle without opening it.
+  /**
+   * This constructor creates a stream handle without opening it. The handle
+   * needs to be opened and then connected or accepted before data can be sent
+   * or received on it.
+   *
+   * @param io_context The io_context object that the stream handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   */
+  explicit basic_stream_handle(asio::io_context& io_context)
+    : basic_handle<StreamHandleService>(io_context)
+  {
+  }
+
+  /// Construct a basic_stream_handle on an existing native handle.
+  /**
+   * This constructor creates a stream handle object to hold an existing native
+   * handle.
+   *
+   * @param io_context The io_context object that the stream handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   *
+   * @param handle The new underlying handle implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  basic_stream_handle(asio::io_context& io_context,
+      const native_handle_type& handle)
+    : basic_handle<StreamHandleService>(io_context, handle)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a basic_stream_handle from another.
+  /**
+   * This constructor moves a stream handle from one object to another.
+   *
+   * @param other The other basic_stream_handle object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_handle(io_context&) constructor.
+   */
+  basic_stream_handle(basic_stream_handle&& other)
+    : basic_handle<StreamHandleService>(
+        ASIO_MOVE_CAST(basic_stream_handle)(other))
+  {
+  }
+
+  /// Move-assign a basic_stream_handle from another.
+  /**
+   * This assignment operator moves a stream handle from one object to
+   * another.
+   *
+   * @param other The other basic_stream_handle object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c basic_stream_handle(io_context&) constructor.
+   */
+  basic_stream_handle& operator=(basic_stream_handle&& other)
+  {
+    basic_handle<StreamHandleService>::operator=(
+        ASIO_MOVE_CAST(basic_stream_handle)(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Write some data to the handle.
+  /**
+   * This function is used to write data to the stream handle. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.write_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return s;
+  }
+
+  /// Write some data to the handle.
+  /**
+   * This function is used to write data to the stream handle. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write data to the stream handle.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_write_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    return this->get_service().async_write_some(this->get_implementation(),
+        buffers, ASIO_MOVE_CAST(WriteHandler)(handler));
+  }
+
+  /// Read some data from the handle.
+  /**
+   * This function is used to read data from the stream handle. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.read_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return s;
+  }
+
+  /// Read some data from the handle.
+  /**
+   * This function is used to read data from the stream handle. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read data from the stream handle.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read function if you need to ensure that the
+   * requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_read_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    return this->get_service().async_read_some(this->get_implementation(),
+        buffers, ASIO_MOVE_CAST(ReadHandler)(handler));
+  }
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_STREAM_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_BASIC_STREAM_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/object_handle.hpp b/subprojects/asio/include/asio/windows/object_handle.hpp
new file mode 100644
index 000000000..581b56800
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/object_handle.hpp
@@ -0,0 +1,381 @@
+//
+// windows/object_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2011 Boris Schaeling (boris@highscore.de)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_OBJECT_HANDLE_HPP
+#define ASIO_WINDOWS_OBJECT_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/async_result.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_object_handle_service.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/windows/basic_object_handle.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#define ASIO_SVC_T asio::detail::win_object_handle_service
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+// Typedef for the typical usage of an object handle.
+typedef basic_object_handle<> object_handle;
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+/// Provides object-oriented handle functionality.
+/**
+ * The windows::object_handle class provides asynchronous and blocking
+ * object-oriented handle functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class object_handle
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The native representation of a handle.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef ASIO_SVC_T::native_handle_type native_handle_type;
+#endif
+
+  /// An object_handle is always the lowest layer.
+  typedef object_handle lowest_layer_type;
+
+  /// Construct an object_handle without opening it.
+  /**
+   * This constructor creates an object handle without opening it.
+   *
+   * @param io_context The io_context object that the object handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   */
+  explicit object_handle(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Construct an object_handle on an existing native handle.
+  /**
+   * This constructor creates an object handle object to hold an existing native
+   * handle.
+   *
+   * @param io_context The io_context object that the object handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   *
+   * @param native_handle The new underlying handle implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  object_handle(asio::io_context& io_context,
+      const native_handle_type& native_handle)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(), native_handle, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct an object_handle from another.
+  /**
+   * This constructor moves an object handle from one object to another.
+   *
+   * @param other The other object_handle object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c object_handle(io_context&) constructor.
+   */
+  object_handle(object_handle&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign an object_handle from another.
+  /**
+   * This assignment operator moves an object handle from one object to another.
+   *
+   * @param other The other object_handle object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c object_handle(io_context&) constructor.
+   */
+  object_handle& operator=(object_handle&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since an object_handle cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since an object_handle cannot contain any further layers, it simply
+   * returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+
+  /// Assign an existing native handle to the handle.
+  /*
+   * This function opens the handle to hold an existing native handle.
+   *
+   * @param handle A native handle.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const native_handle_type& handle)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native handle to the handle.
+  /*
+   * This function opens the handle to hold an existing native handle.
+   *
+   * @param handle A native handle.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const native_handle_type& handle,
+      asio::error_code& ec)
+  {
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the handle is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the handle.
+  /**
+   * This function is used to close the handle. Any asynchronous read or write
+   * operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the handle.
+  /**
+   * This function is used to close the handle. Any asynchronous read or write
+   * operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native handle representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * handle. This is intended to allow access to native handle functionality
+   * that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Perform a blocking wait on the object handle.
+  /**
+   * This function is used to wait for the object handle to be set to the
+   * signalled state. This function blocks and does not return until the object
+   * handle has been set to the signalled state.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void wait()
+  {
+    asio::error_code ec;
+    this->get_service().wait(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "wait");
+  }
+
+  /// Perform a blocking wait on the object handle.
+  /**
+   * This function is used to wait for the object handle to be set to the
+   * signalled state. This function blocks and does not return until the object
+   * handle has been set to the signalled state.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  void wait(asio::error_code& ec)
+  {
+    this->get_service().wait(this->get_implementation(), ec);
+  }
+
+  /// Start an asynchronous wait on the object handle.
+  /**
+   * This function is be used to initiate an asynchronous wait against the
+   * object handle. It always returns immediately.
+   *
+   * @param handler The handler to be called when the object handle is set to
+   * the signalled state. Copies will be made of the handler as required. The
+   * function signature of the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error // Result of operation.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   */
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    asio::async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    this->get_service().async_wait(this->get_implementation(),
+        init.completion_handler);
+
+    return init.result.get();
+  }
+};
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#undef ASIO_SVC_T
+
+#endif // defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_WINDOWS_OBJECT_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/object_handle_service.hpp b/subprojects/asio/include/asio/windows/object_handle_service.hpp
new file mode 100644
index 000000000..95436d790
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/object_handle_service.hpp
@@ -0,0 +1,183 @@
+//
+// windows/object_handle_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2011 Boris Schaeling (boris@highscore.de)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_OBJECT_HANDLE_SERVICE_HPP
+#define ASIO_WINDOWS_OBJECT_HANDLE_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/async_result.hpp"
+#include "asio/detail/win_object_handle_service.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Default service implementation for an object handle.
+class object_handle_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<object_handle_service>
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+private:
+  // The type of the platform-specific implementation.
+  typedef detail::win_object_handle_service service_impl_type;
+
+public:
+  /// The type of an object handle implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native handle type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new object handle service for the specified io_context.
+  explicit object_handle_service(asio::io_context& io_context)
+    : asio::detail::service_base<object_handle_service>(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new object handle implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new object handle implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another object handle implementation.
+  void move_assign(implementation_type& impl,
+      object_handle_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy an object handle implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Assign an existing native handle to an object handle.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const native_handle_type& handle, asio::error_code& ec)
+  {
+    service_impl_.assign(impl, handle, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the handle is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close an object handle implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native handle implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  // Wait for a signaled state.
+  void wait(implementation_type& impl, asio::error_code& ec)
+  {
+    service_impl_.wait(impl, ec);
+  }
+
+  /// Start an asynchronous wait.
+  template <typename WaitHandler>
+  ASIO_INITFN_RESULT_TYPE(WaitHandler,
+      void (asio::error_code))
+  async_wait(implementation_type& impl,
+      ASIO_MOVE_ARG(WaitHandler) handler)
+  {
+    asio::async_completion<WaitHandler,
+      void (asio::error_code)> init(handler);
+
+    service_impl_.async_wait(impl, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_OBJECT_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_OBJECT_HANDLE_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/windows/overlapped_handle.hpp b/subprojects/asio/include/asio/windows/overlapped_handle.hpp
new file mode 100644
index 000000000..3d479ba6c
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/overlapped_handle.hpp
@@ -0,0 +1,331 @@
+//
+// windows/overlapped_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_OVERLAPPED_HANDLE_HPP
+#define ASIO_WINDOWS_OVERLAPPED_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE) \
+  || defined(ASIO_HAS_WINDOWS_STREAM_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/basic_io_object.hpp"
+#include "asio/detail/throw_error.hpp"
+#include "asio/detail/win_iocp_handle_service.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#if defined(ASIO_HAS_MOVE)
+# include <utility>
+#endif // defined(ASIO_HAS_MOVE)
+
+#define ASIO_SVC_T asio::detail::win_iocp_handle_service
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Provides Windows handle functionality for objects that support
+/// overlapped I/O.
+/**
+ * The windows::overlapped_handle class provides the ability to wrap a Windows
+ * handle. The underlying object referred to by the handle must support
+ * overlapped I/O.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class overlapped_handle
+  : ASIO_SVC_ACCESS basic_io_object<ASIO_SVC_T>
+{
+public:
+  /// The type of the executor associated with the object.
+  typedef io_context::executor_type executor_type;
+
+  /// The native representation of a handle.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef ASIO_SVC_T::native_handle_type native_handle_type;
+#endif
+
+  /// An overlapped_handle is always the lowest layer.
+  typedef overlapped_handle lowest_layer_type;
+
+  /// Construct an overlapped_handle without opening it.
+  /**
+   * This constructor creates a handle without opening it.
+   *
+   * @param io_context The io_context object that the handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   */
+  explicit overlapped_handle(asio::io_context& io_context)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+  }
+
+  /// Construct an overlapped_handle on an existing native handle.
+  /**
+   * This constructor creates a handle object to hold an existing native handle.
+   *
+   * @param io_context The io_context object that the handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   *
+   * @param handle A native handle.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  overlapped_handle(asio::io_context& io_context,
+      const native_handle_type& handle)
+    : basic_io_object<ASIO_SVC_T>(io_context)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct an overlapped_handle from another.
+  /**
+   * This constructor moves a handle from one object to another.
+   *
+   * @param other The other overlapped_handle object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c overlapped_handle(io_context&) constructor.
+   */
+  overlapped_handle(overlapped_handle&& other)
+    : basic_io_object<ASIO_SVC_T>(std::move(other))
+  {
+  }
+
+  /// Move-assign an overlapped_handle from another.
+  /**
+   * This assignment operator moves a handle from one object to another.
+   *
+   * @param other The other overlapped_handle object from which the move will
+   * occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c overlapped_handle(io_context&) constructor.
+   */
+  overlapped_handle& operator=(overlapped_handle&& other)
+  {
+    basic_io_object<ASIO_SVC_T>::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+#if !defined(ASIO_NO_DEPRECATED)
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_context()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_context();
+  }
+
+  /// (Deprecated: Use get_executor().) Get the io_context associated with the
+  /// object.
+  /**
+   * This function may be used to obtain the io_context object that the I/O
+   * object uses to dispatch handlers for asynchronous operations.
+   *
+   * @return A reference to the io_context object that the I/O object will use
+   * to dispatch handlers. Ownership is not transferred to the caller.
+   */
+  asio::io_context& get_io_service()
+  {
+    return basic_io_object<ASIO_SVC_T>::get_io_service();
+  }
+#endif // !defined(ASIO_NO_DEPRECATED)
+
+  /// Get the executor associated with the object.
+  executor_type get_executor() ASIO_NOEXCEPT
+  {
+    return basic_io_object<ASIO_SVC_T>::get_executor();
+  }
+
+  /// Get a reference to the lowest layer.
+  /**
+   * This function returns a reference to the lowest layer in a stack of
+   * layers. Since an overlapped_handle cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A reference to the lowest layer in the stack of layers. Ownership
+   * is not transferred to the caller.
+   */
+  lowest_layer_type& lowest_layer()
+  {
+    return *this;
+  }
+
+  /// Get a const reference to the lowest layer.
+  /**
+   * This function returns a const reference to the lowest layer in a stack of
+   * layers. Since an overlapped_handle cannot contain any further layers, it
+   * simply returns a reference to itself.
+   *
+   * @return A const reference to the lowest layer in the stack of layers.
+   * Ownership is not transferred to the caller.
+   */
+  const lowest_layer_type& lowest_layer() const
+  {
+    return *this;
+  }
+
+  /// Assign an existing native handle to the handle.
+  /*
+   * This function opens the handle to hold an existing native handle.
+   *
+   * @param handle A native handle.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void assign(const native_handle_type& handle)
+  {
+    asio::error_code ec;
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    asio::detail::throw_error(ec, "assign");
+  }
+
+  /// Assign an existing native handle to the handle.
+  /*
+   * This function opens the handle to hold an existing native handle.
+   *
+   * @param handle A native handle.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID assign(const native_handle_type& handle,
+      asio::error_code& ec)
+  {
+    this->get_service().assign(this->get_implementation(), handle, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the handle is open.
+  bool is_open() const
+  {
+    return this->get_service().is_open(this->get_implementation());
+  }
+
+  /// Close the handle.
+  /**
+   * This function is used to close the handle. Any asynchronous read or write
+   * operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void close()
+  {
+    asio::error_code ec;
+    this->get_service().close(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "close");
+  }
+
+  /// Close the handle.
+  /**
+   * This function is used to close the handle. Any asynchronous read or write
+   * operations will be cancelled immediately, and will complete with the
+   * asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID close(asio::error_code& ec)
+  {
+    this->get_service().close(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native handle representation.
+  /**
+   * This function may be used to obtain the underlying representation of the
+   * handle. This is intended to allow access to native handle functionality
+   * that is not otherwise provided.
+   */
+  native_handle_type native_handle()
+  {
+    return this->get_service().native_handle(this->get_implementation());
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  void cancel()
+  {
+    asio::error_code ec;
+    this->get_service().cancel(this->get_implementation(), ec);
+    asio::detail::throw_error(ec, "cancel");
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  /**
+   * This function causes all outstanding asynchronous read or write operations
+   * to finish immediately, and the handlers for cancelled operations will be
+   * passed the asio::error::operation_aborted error.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   */
+  ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
+  {
+    this->get_service().cancel(this->get_implementation(), ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+protected:
+  /// Protected destructor to prevent deletion through this type.
+  /**
+   * This function destroys the handle, cancelling any outstanding asynchronous
+   * wait operations associated with the handle as if by calling @c cancel.
+   */
+  ~overlapped_handle()
+  {
+  }
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#undef ASIO_SVC_T
+
+#endif // defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
+       //   || defined(ASIO_HAS_WINDOWS_STREAM_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // !defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_OVERLAPPED_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/overlapped_ptr.hpp b/subprojects/asio/include/asio/windows/overlapped_ptr.hpp
new file mode 100644
index 000000000..ce0b2a42d
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/overlapped_ptr.hpp
@@ -0,0 +1,116 @@
+//
+// windows/overlapped_ptr.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_OVERLAPPED_PTR_HPP
+#define ASIO_WINDOWS_OVERLAPPED_PTR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_HAS_WINDOWS_OVERLAPPED_PTR) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/win_iocp_overlapped_ptr.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Wraps a handler to create an OVERLAPPED object for use with overlapped I/O.
+/**
+ * A special-purpose smart pointer used to wrap an application handler so that
+ * it can be passed as the LPOVERLAPPED argument to overlapped I/O functions.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class overlapped_ptr
+  : private noncopyable
+{
+public:
+  /// Construct an empty overlapped_ptr.
+  overlapped_ptr()
+    : impl_()
+  {
+  }
+
+  /// Construct an overlapped_ptr to contain the specified handler.
+  template <typename Handler>
+  explicit overlapped_ptr(asio::io_context& io_context,
+      ASIO_MOVE_ARG(Handler) handler)
+    : impl_(io_context, ASIO_MOVE_CAST(Handler)(handler))
+  {
+  }
+
+  /// Destructor automatically frees the OVERLAPPED object unless released.
+  ~overlapped_ptr()
+  {
+  }
+
+  /// Reset to empty.
+  void reset()
+  {
+    impl_.reset();
+  }
+
+  /// Reset to contain the specified handler, freeing any current OVERLAPPED
+  /// object.
+  template <typename Handler>
+  void reset(asio::io_context& io_context,
+      ASIO_MOVE_ARG(Handler) handler)
+  {
+    impl_.reset(io_context, ASIO_MOVE_CAST(Handler)(handler));
+  }
+
+  /// Get the contained OVERLAPPED object.
+  OVERLAPPED* get()
+  {
+    return impl_.get();
+  }
+
+  /// Get the contained OVERLAPPED object.
+  const OVERLAPPED* get() const
+  {
+    return impl_.get();
+  }
+
+  /// Release ownership of the OVERLAPPED object.
+  OVERLAPPED* release()
+  {
+    return impl_.release();
+  }
+
+  /// Post completion notification for overlapped operation. Releases ownership.
+  void complete(const asio::error_code& ec,
+      std::size_t bytes_transferred)
+  {
+    impl_.complete(ec, bytes_transferred);
+  }
+
+private:
+  detail::win_iocp_overlapped_ptr impl_;
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_OVERLAPPED_PTR)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_WINDOWS_OVERLAPPED_PTR_HPP
diff --git a/subprojects/asio/include/asio/windows/random_access_handle.hpp b/subprojects/asio/include/asio/windows/random_access_handle.hpp
new file mode 100644
index 000000000..301d5f8dd
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/random_access_handle.hpp
@@ -0,0 +1,378 @@
+//
+// windows/random_access_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_HPP
+#define ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/windows/overlapped_handle.hpp"
+
+#if defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/windows/basic_random_access_handle.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+// Typedef for the typical usage of a random-access handle.
+typedef basic_random_access_handle<> random_access_handle;
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+/// Provides random-access handle functionality.
+/**
+ * The windows::random_access_handle class provides asynchronous and
+ * blocking random-access handle functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ */
+class random_access_handle
+  : public overlapped_handle
+{
+public:
+  /// Construct a random_access_handle without opening it.
+  /**
+   * This constructor creates a random-access handle without opening it. The
+   * handle needs to be opened before data can be written to or read from it.
+   *
+   * @param io_context The io_context object that the random-access handle will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * handle.
+   */
+  explicit random_access_handle(asio::io_context& io_context)
+    : overlapped_handle(io_context)
+  {
+  }
+
+  /// Construct a random_access_handle on an existing native handle.
+  /**
+   * This constructor creates a random-access handle object to hold an existing
+   * native handle.
+   *
+   * @param io_context The io_context object that the random-access handle will
+   * use to dispatch handlers for any asynchronous operations performed on the
+   * handle.
+   *
+   * @param handle The new underlying handle implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  random_access_handle(asio::io_context& io_context,
+      const native_handle_type& handle)
+    : overlapped_handle(io_context, handle)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a random_access_handle from another.
+  /**
+   * This constructor moves a random-access handle from one object to another.
+   *
+   * @param other The other random_access_handle object from which the
+   * move will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c random_access_handle(io_context&)
+   * constructor.
+   */
+  random_access_handle(random_access_handle&& other)
+    : overlapped_handle(std::move(other))
+  {
+  }
+
+  /// Move-assign a random_access_handle from another.
+  /**
+   * This assignment operator moves a random-access handle from one object to
+   * another.
+   *
+   * @param other The other random_access_handle object from which the
+   * move will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c random_access_handle(io_context&)
+   * constructor.
+   */
+  random_access_handle& operator=(random_access_handle&& other)
+  {
+    overlapped_handle::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Write some data to the handle at the specified offset.
+  /**
+   * This function is used to write data to the random-access handle. The
+   * function call will block until one or more bytes of the data has been
+   * written successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be written.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some_at operation may not write all of the data. Consider
+   * using the @ref write_at function if you need to ensure that all data is
+   * written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.write_some_at(42, asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some_at(uint64_t offset,
+      const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some_at(
+        this->get_implementation(), offset, buffers, ec);
+    asio::detail::throw_error(ec, "write_some_at");
+    return s;
+  }
+
+  /// Write some data to the handle at the specified offset.
+  /**
+   * This function is used to write data to the random-access handle. The
+   * function call will block until one or more bytes of the data has been
+   * written successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be written.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write_at function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some_at(uint64_t offset,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return this->get_service().write_some_at(
+        this->get_implementation(), offset, buffers, ec);
+  }
+
+  /// Start an asynchronous write at the specified offset.
+  /**
+   * This function is used to asynchronously write data to the random-access
+   * handle. The function call always returns immediately.
+   *
+   * @param offset The offset at which the data will be written.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write_at function if you need to ensure that
+   * all data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_write_some_at(42, asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some_at(uint64_t offset,
+      const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    asio::async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_write_some_at(this->get_implementation(),
+        offset, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the handle at the specified offset.
+  /**
+   * This function is used to read data from the random-access handle. The
+   * function call will block until one or more bytes of data has been read
+   * successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be read.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read_at function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.read_some_at(42, asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some_at(uint64_t offset,
+      const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some_at(
+        this->get_implementation(), offset, buffers, ec);
+    asio::detail::throw_error(ec, "read_some_at");
+    return s;
+  }
+
+  /// Read some data from the handle at the specified offset.
+  /**
+   * This function is used to read data from the random-access handle. The
+   * function call will block until one or more bytes of data has been read
+   * successfully, or until an error occurs.
+   *
+   * @param offset The offset at which the data will be read.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read_at function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some_at(uint64_t offset,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return this->get_service().read_some_at(
+        this->get_implementation(), offset, buffers, ec);
+  }
+
+  /// Start an asynchronous read at the specified offset.
+  /**
+   * This function is used to asynchronously read data from the random-access
+   * handle. The function call always returns immediately.
+   *
+   * @param offset The offset at which the data will be read.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read_at function if you need to ensure that
+   * the requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_read_some_at(42, asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some_at(uint64_t offset,
+      const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    asio::async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_read_some_at(this->get_implementation(),
+        offset, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+};
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/random_access_handle_service.hpp b/subprojects/asio/include/asio/windows/random_access_handle_service.hpp
new file mode 100644
index 000000000..ebccf3e39
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/random_access_handle_service.hpp
@@ -0,0 +1,214 @@
+//
+// windows/random_access_handle_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_SERVICE_HPP
+#define ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/cstdint.hpp"
+#include "asio/detail/win_iocp_handle_service.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Default service implementation for a random-access handle.
+class random_access_handle_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<random_access_handle_service>
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+private:
+  // The type of the platform-specific implementation.
+  typedef detail::win_iocp_handle_service service_impl_type;
+
+public:
+  /// The type of a random-access handle implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native handle type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new random-access handle service for the specified io_context.
+  explicit random_access_handle_service(asio::io_context& io_context)
+    : asio::detail::service_base<
+        random_access_handle_service>(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new random-access handle implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new random-access handle implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another random-access handle implementation.
+  void move_assign(implementation_type& impl,
+      random_access_handle_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a random-access handle implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Assign an existing native handle to a random-access handle.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const native_handle_type& handle, asio::error_code& ec)
+  {
+    service_impl_.assign(impl, handle, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the handle is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a random-access handle implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native handle implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Write the given data at the specified offset.
+  template <typename ConstBufferSequence>
+  std::size_t write_some_at(implementation_type& impl, uint64_t offset,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.write_some_at(impl, offset, buffers, ec);
+  }
+
+  /// Start an asynchronous write at the specified offset.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some_at(implementation_type& impl,
+      uint64_t offset, const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    asio::async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_write_some_at(impl,
+        offset, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the specified offset.
+  template <typename MutableBufferSequence>
+  std::size_t read_some_at(implementation_type& impl, uint64_t offset,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.read_some_at(impl, offset, buffers, ec);
+  }
+
+  /// Start an asynchronous read at the specified offset.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some_at(implementation_type& impl,
+      uint64_t offset, const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    asio::async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_read_some_at(impl,
+        offset, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/windows/stream_handle.hpp b/subprojects/asio/include/asio/windows/stream_handle.hpp
new file mode 100644
index 000000000..8f0a21b1f
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/stream_handle.hpp
@@ -0,0 +1,362 @@
+//
+// windows/stream_handle.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_STREAM_HANDLE_HPP
+#define ASIO_WINDOWS_STREAM_HANDLE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/windows/overlapped_handle.hpp"
+
+#if defined(ASIO_HAS_WINDOWS_STREAM_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+# include "asio/windows/basic_stream_handle.hpp"
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+// Typedef for the typical usage of a stream-oriented handle.
+typedef basic_stream_handle<> stream_handle;
+#else // defined(ASIO_ENABLE_OLD_SERVICES)
+/// Provides stream-oriented handle functionality.
+/**
+ * The windows::stream_handle class provides asynchronous and blocking
+ * stream-oriented handle functionality.
+ *
+ * @par Thread Safety
+ * @e Distinct @e objects: Safe.@n
+ * @e Shared @e objects: Unsafe.
+ *
+ * @par Concepts:
+ * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
+ */
+class stream_handle
+  : public overlapped_handle
+{
+public:
+  /// Construct a stream_handle without opening it.
+  /**
+   * This constructor creates a stream handle without opening it. The handle
+   * needs to be opened and then connected or accepted before data can be sent
+   * or received on it.
+   *
+   * @param io_context The io_context object that the stream handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   */
+  explicit stream_handle(asio::io_context& io_context)
+    : overlapped_handle(io_context)
+  {
+  }
+
+  /// Construct a stream_handle on an existing native handle.
+  /**
+   * This constructor creates a stream handle object to hold an existing native
+   * handle.
+   *
+   * @param io_context The io_context object that the stream handle will use to
+   * dispatch handlers for any asynchronous operations performed on the handle.
+   *
+   * @param handle The new underlying handle implementation.
+   *
+   * @throws asio::system_error Thrown on failure.
+   */
+  stream_handle(asio::io_context& io_context,
+      const native_handle_type& handle)
+    : overlapped_handle(io_context, handle)
+  {
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a stream_handle from another.
+  /**
+   * This constructor moves a stream handle from one object to another.
+   *
+   * @param other The other stream_handle object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c stream_handle(io_context&) constructor.
+   */
+  stream_handle(stream_handle&& other)
+    : overlapped_handle(std::move(other))
+  {
+  }
+
+  /// Move-assign a stream_handle from another.
+  /**
+   * This assignment operator moves a stream handle from one object to
+   * another.
+   *
+   * @param other The other stream_handle object from which the move
+   * will occur.
+   *
+   * @note Following the move, the moved-from object is in the same state as if
+   * constructed using the @c stream_handle(io_context&) constructor.
+   */
+  stream_handle& operator=(stream_handle&& other)
+  {
+    overlapped_handle::operator=(std::move(other));
+    return *this;
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Write some data to the handle.
+  /**
+   * This function is used to write data to the stream handle. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @returns The number of bytes written.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.write_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "write_some");
+    return s;
+  }
+
+  /// Write some data to the handle.
+  /**
+   * This function is used to write data to the stream handle. The function call
+   * will block until one or more bytes of the data has been written
+   * successfully, or until an error occurs.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes written. Returns 0 if an error occurred.
+   *
+   * @note The write_some operation may not transmit all of the data to the
+   * peer. Consider using the @ref write function if you need to ensure that
+   * all data is written before the blocking operation completes.
+   */
+  template <typename ConstBufferSequence>
+  std::size_t write_some(const ConstBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().write_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  /**
+   * This function is used to asynchronously write data to the stream handle.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more data buffers to be written to the handle.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the write operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes written.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The write operation may not transmit all of the data to the peer.
+   * Consider using the @ref async_write function if you need to ensure that all
+   * data is written before the asynchronous operation completes.
+   *
+   * @par Example
+   * To write a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_write_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on writing multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a WriteHandler.
+    ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
+
+    asio::async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_write_some(
+        this->get_implementation(), buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the handle.
+  /**
+   * This function is used to read data from the stream handle. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @returns The number of bytes read.
+   *
+   * @throws asio::system_error Thrown on failure. An error code of
+   * asio::error::eof indicates that the connection was closed by the
+   * peer.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.read_some(asio::buffer(data, size));
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers)
+  {
+    asio::error_code ec;
+    std::size_t s = this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+    asio::detail::throw_error(ec, "read_some");
+    return s;
+  }
+
+  /// Read some data from the handle.
+  /**
+   * This function is used to read data from the stream handle. The function
+   * call will block until one or more bytes of data has been read successfully,
+   * or until an error occurs.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   *
+   * @param ec Set to indicate what error occurred, if any.
+   *
+   * @returns The number of bytes read. Returns 0 if an error occurred.
+   *
+   * @note The read_some operation may not read all of the requested number of
+   * bytes. Consider using the @ref read function if you need to ensure that
+   * the requested amount of data is read before the blocking operation
+   * completes.
+   */
+  template <typename MutableBufferSequence>
+  std::size_t read_some(const MutableBufferSequence& buffers,
+      asio::error_code& ec)
+  {
+    return this->get_service().read_some(
+        this->get_implementation(), buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  /**
+   * This function is used to asynchronously read data from the stream handle.
+   * The function call always returns immediately.
+   *
+   * @param buffers One or more buffers into which the data will be read.
+   * Although the buffers object may be copied as necessary, ownership of the
+   * underlying memory blocks is retained by the caller, which must guarantee
+   * that they remain valid until the handler is called.
+   *
+   * @param handler The handler to be called when the read operation completes.
+   * Copies will be made of the handler as required. The function signature of
+   * the handler must be:
+   * @code void handler(
+   *   const asio::error_code& error, // Result of operation.
+   *   std::size_t bytes_transferred           // Number of bytes read.
+   * ); @endcode
+   * Regardless of whether the asynchronous operation completes immediately or
+   * not, the handler will not be invoked from within this function. Invocation
+   * of the handler will be performed in a manner equivalent to using
+   * asio::io_context::post().
+   *
+   * @note The read operation may not read all of the requested number of bytes.
+   * Consider using the @ref async_read function if you need to ensure that the
+   * requested amount of data is read before the asynchronous operation
+   * completes.
+   *
+   * @par Example
+   * To read into a single data buffer use the @ref buffer function as follows:
+   * @code
+   * handle.async_read_some(asio::buffer(data, size), handler);
+   * @endcode
+   * See the @ref buffer documentation for information on reading into multiple
+   * buffers in one go, and how to use it with arrays, boost::array or
+   * std::vector.
+   */
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    // If you get an error on the following line it means that your handler does
+    // not meet the documented type requirements for a ReadHandler.
+    ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
+
+    asio::async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    this->get_service().async_read_some(
+        this->get_implementation(), buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+};
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_STREAM_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // ASIO_WINDOWS_STREAM_HANDLE_HPP
diff --git a/subprojects/asio/include/asio/windows/stream_handle_service.hpp b/subprojects/asio/include/asio/windows/stream_handle_service.hpp
new file mode 100644
index 000000000..1c665d5e1
--- /dev/null
+++ b/subprojects/asio/include/asio/windows/stream_handle_service.hpp
@@ -0,0 +1,210 @@
+//
+// windows/stream_handle_service.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WINDOWS_STREAM_HANDLE_SERVICE_HPP
+#define ASIO_WINDOWS_STREAM_HANDLE_SERVICE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#if defined(ASIO_ENABLE_OLD_SERVICES)
+
+#if defined(ASIO_HAS_WINDOWS_STREAM_HANDLE) \
+  || defined(GENERATING_DOCUMENTATION)
+
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/win_iocp_handle_service.hpp"
+#include "asio/error.hpp"
+#include "asio/io_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace windows {
+
+/// Default service implementation for a stream handle.
+class stream_handle_service
+#if defined(GENERATING_DOCUMENTATION)
+  : public asio::io_context::service
+#else
+  : public asio::detail::service_base<stream_handle_service>
+#endif
+{
+public:
+#if defined(GENERATING_DOCUMENTATION)
+  /// The unique service identifier.
+  static asio::io_context::id id;
+#endif
+
+private:
+  // The type of the platform-specific implementation.
+  typedef detail::win_iocp_handle_service service_impl_type;
+
+public:
+  /// The type of a stream handle implementation.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined implementation_type;
+#else
+  typedef service_impl_type::implementation_type implementation_type;
+#endif
+
+  /// The native handle type.
+#if defined(GENERATING_DOCUMENTATION)
+  typedef implementation_defined native_handle_type;
+#else
+  typedef service_impl_type::native_handle_type native_handle_type;
+#endif
+
+  /// Construct a new stream handle service for the specified io_context.
+  explicit stream_handle_service(asio::io_context& io_context)
+    : asio::detail::service_base<stream_handle_service>(io_context),
+      service_impl_(io_context)
+  {
+  }
+
+  /// Construct a new stream handle implementation.
+  void construct(implementation_type& impl)
+  {
+    service_impl_.construct(impl);
+  }
+
+#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+  /// Move-construct a new stream handle implementation.
+  void move_construct(implementation_type& impl,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_construct(impl, other_impl);
+  }
+
+  /// Move-assign from another stream handle implementation.
+  void move_assign(implementation_type& impl,
+      stream_handle_service& other_service,
+      implementation_type& other_impl)
+  {
+    service_impl_.move_assign(impl, other_service.service_impl_, other_impl);
+  }
+#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+
+  /// Destroy a stream handle implementation.
+  void destroy(implementation_type& impl)
+  {
+    service_impl_.destroy(impl);
+  }
+
+  /// Assign an existing native handle to a stream handle.
+  ASIO_SYNC_OP_VOID assign(implementation_type& impl,
+      const native_handle_type& handle, asio::error_code& ec)
+  {
+    service_impl_.assign(impl, handle, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Determine whether the handle is open.
+  bool is_open(const implementation_type& impl) const
+  {
+    return service_impl_.is_open(impl);
+  }
+
+  /// Close a stream handle implementation.
+  ASIO_SYNC_OP_VOID close(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.close(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Get the native handle implementation.
+  native_handle_type native_handle(implementation_type& impl)
+  {
+    return service_impl_.native_handle(impl);
+  }
+
+  /// Cancel all asynchronous operations associated with the handle.
+  ASIO_SYNC_OP_VOID cancel(implementation_type& impl,
+      asio::error_code& ec)
+  {
+    service_impl_.cancel(impl, ec);
+    ASIO_SYNC_OP_VOID_RETURN(ec);
+  }
+
+  /// Write the given data to the stream.
+  template <typename ConstBufferSequence>
+  std::size_t write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.write_some(impl, buffers, ec);
+  }
+
+  /// Start an asynchronous write.
+  template <typename ConstBufferSequence, typename WriteHandler>
+  ASIO_INITFN_RESULT_TYPE(WriteHandler,
+      void (asio::error_code, std::size_t))
+  async_write_some(implementation_type& impl,
+      const ConstBufferSequence& buffers,
+      ASIO_MOVE_ARG(WriteHandler) handler)
+  {
+    asio::async_completion<WriteHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_write_some(impl, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+  /// Read some data from the stream.
+  template <typename MutableBufferSequence>
+  std::size_t read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers, asio::error_code& ec)
+  {
+    return service_impl_.read_some(impl, buffers, ec);
+  }
+
+  /// Start an asynchronous read.
+  template <typename MutableBufferSequence, typename ReadHandler>
+  ASIO_INITFN_RESULT_TYPE(ReadHandler,
+      void (asio::error_code, std::size_t))
+  async_read_some(implementation_type& impl,
+      const MutableBufferSequence& buffers,
+      ASIO_MOVE_ARG(ReadHandler) handler)
+  {
+    asio::async_completion<ReadHandler,
+      void (asio::error_code, std::size_t)> init(handler);
+
+    service_impl_.async_read_some(impl, buffers, init.completion_handler);
+
+    return init.result.get();
+  }
+
+private:
+  // Destroy all user-defined handler objects owned by the service.
+  void shutdown()
+  {
+    service_impl_.shutdown();
+  }
+
+  // The platform-specific implementation.
+  service_impl_type service_impl_;
+};
+
+} // namespace windows
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // defined(ASIO_HAS_WINDOWS_STREAM_HANDLE)
+       //   || defined(GENERATING_DOCUMENTATION)
+
+#endif // defined(ASIO_ENABLE_OLD_SERVICES)
+
+#endif // ASIO_WINDOWS_STREAM_HANDLE_SERVICE_HPP
diff --git a/subprojects/asio/include/asio/write.hpp b/subprojects/asio/include/asio/write.hpp
new file mode 100644
index 000000000..7f9251a87
--- /dev/null
+++ b/subprojects/asio/include/asio/write.hpp
@@ -0,0 +1,928 @@
+//
+// write.hpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WRITE_HPP
+#define ASIO_WRITE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/buffer.hpp"
+#include "asio/error.hpp"
+
+#if !defined(ASIO_NO_EXTENSIONS)
+# include "asio/basic_streambuf_fwd.hpp"
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/**
+ * @defgroup write asio::write
+ *
+ * @brief The @c write function is a composed operation that writes a certain
+ * amount of data to a stream before returning.
+ */
+/*@{*/
+
+/// Write all of the supplied data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * stream.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::write(s, asio::buffer(data, size)); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write(
+ *     s, buffers,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncWriteStream, typename ConstBufferSequence>
+std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type* = 0);
+
+/// Write all of the supplied data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * stream.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::write(s, asio::buffer(data, size), ec); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write(
+ *     s, buffers,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncWriteStream, typename ConstBufferSequence>
+std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type* = 0);
+
+/// Write a certain amount of data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * stream.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's write_some function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::write(s, asio::buffer(data, size),
+ *     asio::transfer_at_least(32)); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename SyncWriteStream, typename ConstBufferSequence,
+    typename CompletionCondition>
+std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type* = 0);
+
+/// Write a certain amount of data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * stream.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's write_some function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes written. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncWriteStream, typename ConstBufferSequence,
+    typename CompletionCondition>
+std::size_t write(SyncWriteStream& s, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type* = 0);
+
+/// Write all of the supplied data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied dynamic buffer sequence has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers The dynamic buffer sequence from which data will be written.
+ * Successfully written data is automatically consumed from the buffers.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write(
+ *     s, buffers,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncWriteStream, typename DynamicBuffer>
+std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Write all of the supplied data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied dynamic buffer sequence has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers The dynamic buffer sequence from which data will be written.
+ * Successfully written data is automatically consumed from the buffers.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write(
+ *     s, buffers,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncWriteStream, typename DynamicBuffer>
+std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Write a certain amount of data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied dynamic buffer sequence has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers The dynamic buffer sequence from which data will be written.
+ * Successfully written data is automatically consumed from the buffers.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's write_some function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ */
+template <typename SyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition>
+std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Write a certain amount of data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied dynamic buffer sequence has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param buffers The dynamic buffer sequence from which data will be written.
+ * Successfully written data is automatically consumed from the buffers.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's write_some function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes written. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition>
+std::size_t write(SyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition, asio::error_code& ec,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Write all of the supplied data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write(
+ *     s, b,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncWriteStream, typename Allocator>
+std::size_t write(SyncWriteStream& s, basic_streambuf<Allocator>& b);
+
+/// Write all of the supplied data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write(
+ *     s, b,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncWriteStream, typename Allocator>
+std::size_t write(SyncWriteStream& s, basic_streambuf<Allocator>& b,
+    asio::error_code& ec);
+
+/// Write a certain amount of data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's write_some function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ */
+template <typename SyncWriteStream, typename Allocator,
+    typename CompletionCondition>
+std::size_t write(SyncWriteStream& s, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition);
+
+/// Write a certain amount of data to a stream before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a stream.
+ * The call will block until one of the following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * write_some function.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the SyncWriteStream concept.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's write_some function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes written. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncWriteStream, typename Allocator,
+    typename CompletionCondition>
+std::size_t write(SyncWriteStream& s, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition, asio::error_code& ec);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+/**
+ * @defgroup async_write asio::async_write
+ *
+ * @brief The @c async_write function is a composed asynchronous operation that
+ * writes a certain amount of data to a stream before completion.
+ */
+/*@{*/
+
+/// Start an asynchronous operation to write all of the supplied data to a
+/// stream.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_write_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other write operations (such
+ * as async_write, the stream's async_write_some function, or any other composed
+ * operations that perform writes) until this operation completes.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the AsyncWriteStream concept.
+ *
+ * @param buffers One or more buffers containing the data to be written.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of
+ * the handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes written from the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be less than the sum
+ *                                           // of the buffer sizes.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code
+ * asio::async_write(s, asio::buffer(data, size), handler);
+ * @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename AsyncWriteStream, typename ConstBufferSequence,
+    typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s, const ConstBufferSequence& buffers,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type* = 0);
+
+/// Start an asynchronous operation to write a certain amount of data to a
+/// stream.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_write_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other write operations (such
+ * as async_write, the stream's async_write_some function, or any other composed
+ * operations that perform writes) until this operation completes.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the AsyncWriteStream concept.
+ *
+ * @param buffers One or more buffers containing the data to be written.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's async_write_some function.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes written from the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be less than the sum
+ *                                           // of the buffer sizes.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::async_write(s,
+ *     asio::buffer(data, size),
+ *     asio::transfer_at_least(32),
+ *     handler); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename AsyncWriteStream, typename ConstBufferSequence,
+    typename CompletionCondition, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_const_buffer_sequence<ConstBufferSequence>::value
+    >::type* = 0);
+
+/// Start an asynchronous operation to write all of the supplied data to a
+/// stream.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li All of the data in the supplied dynamic buffer sequence has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_write_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other write operations (such
+ * as async_write, the stream's async_write_some function, or any other composed
+ * operations that perform writes) until this operation completes.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the AsyncWriteStream concept.
+ *
+ * @param buffers The dynamic buffer sequence from which data will be written.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called. Successfully written
+ * data is automatically consumed from the buffers.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes written from the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be less than the sum
+ *                                           // of the buffer sizes.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncWriteStream,
+    typename DynamicBuffer, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+/// Start an asynchronous operation to write a certain amount of data to a
+/// stream.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li All of the data in the supplied dynamic buffer sequence has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_write_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other write operations (such
+ * as async_write, the stream's async_write_some function, or any other composed
+ * operations that perform writes) until this operation completes.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the AsyncWriteStream concept.
+ *
+ * @param buffers The dynamic buffer sequence from which data will be written.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called. Successfully written
+ * data is automatically consumed from the buffers.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's async_write_some function.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes written from the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be less than the sum
+ *                                           // of the buffer sizes.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncWriteStream, typename DynamicBuffer,
+    typename CompletionCondition, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s,
+    ASIO_MOVE_ARG(DynamicBuffer) buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler,
+    typename enable_if<
+      is_dynamic_buffer<typename decay<DynamicBuffer>::type>::value
+    >::type* = 0);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Start an asynchronous operation to write all of the supplied data to a
+/// stream.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_write_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other write operations (such
+ * as async_write, the stream's async_write_some function, or any other composed
+ * operations that perform writes) until this operation completes.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the AsyncWriteStream concept.
+ *
+ * @param b A basic_streambuf object from which data will be written. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes written from the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be less than the sum
+ *                                           // of the buffer sizes.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncWriteStream, typename Allocator, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s, basic_streambuf<Allocator>& b,
+    ASIO_MOVE_ARG(WriteHandler) handler);
+
+/// Start an asynchronous operation to write a certain amount of data to a
+/// stream.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a stream. The function call always returns immediately. The
+ * asynchronous operation will continue until one of the following conditions
+ * is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the stream's
+ * async_write_some function, and is known as a <em>composed operation</em>. The
+ * program must ensure that the stream performs no other write operations (such
+ * as async_write, the stream's async_write_some function, or any other composed
+ * operations that perform writes) until this operation completes.
+ *
+ * @param s The stream to which the data is to be written. The type must support
+ * the AsyncWriteStream concept.
+ *
+ * @param b A basic_streambuf object from which data will be written. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_write_some operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the stream's async_write_some function.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   const asio::error_code& error, // Result of operation.
+ *
+ *   std::size_t bytes_transferred           // Number of bytes written from the
+ *                                           // buffers. If an error occurred,
+ *                                           // this will be less than the sum
+ *                                           // of the buffer sizes.
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncWriteStream, typename Allocator,
+    typename CompletionCondition, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write(AsyncWriteStream& s, basic_streambuf<Allocator>& b,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/write.hpp"
+
+#endif // ASIO_WRITE_HPP
diff --git a/subprojects/asio/include/asio/write_at.hpp b/subprojects/asio/include/asio/write_at.hpp
new file mode 100644
index 000000000..b7e5da482
--- /dev/null
+++ b/subprojects/asio/include/asio/write_at.hpp
@@ -0,0 +1,679 @@
+//
+// write_at.hpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_WRITE_AT_HPP
+#define ASIO_WRITE_AT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include "asio/async_result.hpp"
+#include "asio/detail/cstdint.hpp"
+#include "asio/error.hpp"
+
+#if !defined(ASIO_NO_EXTENSIONS)
+# include "asio/basic_streambuf_fwd.hpp"
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+/**
+ * @defgroup write_at asio::write_at
+ *
+ * @brief The @c write_at function is a composed operation that writes a
+ * certain amount of data at a specified offset before returning.
+ */
+/*@{*/
+
+/// Write all of the supplied data at the specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::write_at(d, 42, asio::buffer(data, size)); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write_at(
+ *     d, offset, buffers,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers);
+
+/// Write all of the supplied data at the specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::write_at(d, 42,
+ *     asio::buffer(data, size), ec); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write_at(
+ *     d, offset, buffers,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    asio::error_code& ec);
+
+/// Write a certain amount of data at a specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the device's write_some_at function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::write_at(d, 42, asio::buffer(data, size),
+ *     asio::transfer_at_least(32)); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition);
+
+/// Write a certain amount of data at a specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the device's write_some_at function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes written. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition, asio::error_code& ec);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Write all of the supplied data at the specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write_at(
+ *     d, 42, b,
+ *     asio::transfer_all()); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename Allocator>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b);
+
+/// Write all of the supplied data at the specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @note This overload is equivalent to calling:
+ * @code asio::write_at(
+ *     d, 42, b,
+ *     asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename Allocator>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b,
+    asio::error_code& ec);
+
+/// Write a certain amount of data at a specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the device's write_some_at function.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws asio::system_error Thrown on failure.
+ */
+template <typename SyncRandomAccessWriteDevice, typename Allocator,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d, uint64_t offset,
+    basic_streambuf<Allocator>& b, CompletionCondition completion_condition);
+
+/// Write a certain amount of data at a specified offset before returning.
+/**
+ * This function is used to write a certain number of bytes of data to a random
+ * access device at a specified offset. The call will block until one of the
+ * following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * write_some_at function.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the SyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param b The basic_streambuf object from which data will be written.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest write_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the device's write_some_at function.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes written. If an error occurs, returns the total
+ * number of bytes successfully transferred prior to the error.
+ */
+template <typename SyncRandomAccessWriteDevice, typename Allocator,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d, uint64_t offset,
+    basic_streambuf<Allocator>& b, CompletionCondition completion_condition,
+    asio::error_code& ec);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+/**
+ * @defgroup async_write_at asio::async_write_at
+ *
+ * @brief The @c async_write_at function is a composed asynchronous operation
+ * that writes a certain amount of data at the specified offset before
+ * completion.
+ */
+/*@{*/
+
+/// Start an asynchronous operation to write all of the supplied data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a random access device at a specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * async_write_some_at function, and is known as a <em>composed operation</em>.
+ * The program must ensure that the device performs no <em>overlapping</em>
+ * write operations (such as async_write_at, the device's async_write_some_at
+ * function, or any other composed operations that perform writes) until this
+ * operation completes. Operations are overlapping if the regions defined by
+ * their offsets, and the numbers of bytes to write, intersect.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the AsyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param buffers One or more buffers containing the data to be written.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of
+ * the handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes written from the buffers. If an error
+ *   // occurred, this will be less than the sum of the buffer sizes.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code
+ * asio::async_write_at(d, 42, asio::buffer(data, size), handler);
+ * @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
+    const ConstBufferSequence& buffers,
+    ASIO_MOVE_ARG(WriteHandler) handler);
+
+/// Start an asynchronous operation to write a certain amount of data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a random access device at a specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li All of the data in the supplied buffers has been written. That is, the
+ * bytes transferred is equal to the sum of the buffer sizes.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * async_write_some_at function, and is known as a <em>composed operation</em>.
+ * The program must ensure that the device performs no <em>overlapping</em>
+ * write operations (such as async_write_at, the device's async_write_some_at
+ * function, or any other composed operations that perform writes) until this
+ * operation completes. Operations are overlapping if the regions defined by
+ * their offsets, and the numbers of bytes to write, intersect.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the AsyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param buffers One or more buffers containing the data to be written.
+ * Although the buffers object may be copied as necessary, ownership of the
+ * underlying memory blocks is retained by the caller, which must guarantee
+ * that they remain valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_write_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the device's async_write_some_at function.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes written from the buffers. If an error
+ *   // occurred, this will be less than the sum of the buffer sizes.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code asio::async_write_at(d, 42,
+ *     asio::buffer(data, size),
+ *     asio::transfer_at_least(32),
+ *     handler); @endcode
+ * See the @ref buffer documentation for information on writing multiple
+ * buffers in one go, and how to use it with arrays, boost::array or
+ * std::vector.
+ */
+template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler);
+
+#if !defined(ASIO_NO_EXTENSIONS)
+#if !defined(ASIO_NO_IOSTREAM)
+
+/// Start an asynchronous operation to write all of the supplied data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a random access device at a specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li An error occurred.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * async_write_some_at function, and is known as a <em>composed operation</em>.
+ * The program must ensure that the device performs no <em>overlapping</em>
+ * write operations (such as async_write_at, the device's async_write_some_at
+ * function, or any other composed operations that perform writes) until this
+ * operation completes. Operations are overlapping if the regions defined by
+ * their offsets, and the numbers of bytes to write, intersect.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the AsyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param b A basic_streambuf object from which data will be written. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes written from the buffers. If an error
+ *   // occurred, this will be less than the sum of the buffer sizes.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncRandomAccessWriteDevice, typename Allocator,
+    typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
+    basic_streambuf<Allocator>& b, ASIO_MOVE_ARG(WriteHandler) handler);
+
+/// Start an asynchronous operation to write a certain amount of data at the
+/// specified offset.
+/**
+ * This function is used to asynchronously write a certain number of bytes of
+ * data to a random access device at a specified offset. The function call
+ * always returns immediately. The asynchronous operation will continue until
+ * one of the following conditions is true:
+ *
+ * @li All of the data in the supplied basic_streambuf has been written.
+ *
+ * @li The completion_condition function object returns 0.
+ *
+ * This operation is implemented in terms of zero or more calls to the device's
+ * async_write_some_at function, and is known as a <em>composed operation</em>.
+ * The program must ensure that the device performs no <em>overlapping</em>
+ * write operations (such as async_write_at, the device's async_write_some_at
+ * function, or any other composed operations that perform writes) until this
+ * operation completes. Operations are overlapping if the regions defined by
+ * their offsets, and the numbers of bytes to write, intersect.
+ *
+ * @param d The device to which the data is to be written. The type must support
+ * the AsyncRandomAccessWriteDevice concept.
+ *
+ * @param offset The offset at which the data will be written.
+ *
+ * @param b A basic_streambuf object from which data will be written. Ownership
+ * of the streambuf is retained by the caller, which must guarantee that it
+ * remains valid until the handler is called.
+ *
+ * @param completion_condition The function object to be called to determine
+ * whether the write operation is complete. The signature of the function object
+ * must be:
+ * @code std::size_t completion_condition(
+ *   // Result of latest async_write_some_at operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes transferred so far.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * A return value of 0 indicates that the write operation is complete. A
+ * non-zero return value indicates the maximum number of bytes to be written on
+ * the next call to the device's async_write_some_at function.
+ *
+ * @param handler The handler to be called when the write operation completes.
+ * Copies will be made of the handler as required. The function signature of the
+ * handler must be:
+ * @code void handler(
+ *   // Result of operation.
+ *   const asio::error_code& error,
+ *
+ *   // Number of bytes written from the buffers. If an error
+ *   // occurred, this will be less than the sum of the buffer sizes.
+ *   std::size_t bytes_transferred
+ * ); @endcode
+ * Regardless of whether the asynchronous operation completes immediately or
+ * not, the handler will not be invoked from within this function. Invocation of
+ * the handler will be performed in a manner equivalent to using
+ * asio::io_context::post().
+ */
+template <typename AsyncRandomAccessWriteDevice, typename Allocator,
+    typename CompletionCondition, typename WriteHandler>
+ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (asio::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
+    basic_streambuf<Allocator>& b, CompletionCondition completion_condition,
+    ASIO_MOVE_ARG(WriteHandler) handler);
+
+#endif // !defined(ASIO_NO_IOSTREAM)
+#endif // !defined(ASIO_NO_EXTENSIONS)
+
+/*@}*/
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/write_at.hpp"
+
+#endif // ASIO_WRITE_AT_HPP
diff --git a/subprojects/asio/include/asio/yield.hpp b/subprojects/asio/include/asio/yield.hpp
new file mode 100644
index 000000000..b527ac9b4
--- /dev/null
+++ b/subprojects/asio/include/asio/yield.hpp
@@ -0,0 +1,23 @@
+//
+// yield.hpp
+// ~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include "coroutine.hpp"
+
+#ifndef reenter
+# define reenter(c) ASIO_CORO_REENTER(c)
+#endif
+
+#ifndef yield
+# define yield ASIO_CORO_YIELD
+#endif
+
+#ifndef fork
+# define fork ASIO_CORO_FORK
+#endif
diff --git a/subprojects/valijson/Authors b/subprojects/valijson/Authors
new file mode 100644
index 000000000..d2c0206d3
--- /dev/null
+++ b/subprojects/valijson/Authors
@@ -0,0 +1,38 @@
+Tristan Penman, tristan@tristanpenman.com
+	Core library development
+
+James Jensen, jjensen@akamai.com, changes Copyright (c) 2016 Akamai Technologies
+	Polymorphic constraint support
+
+Tengiz Sharafiev, btolfa+github@gmail.com
+	Adapter for nlohmann/json parser library
+
+hotwatermorning (github username), hotwatermorning@gmail.com
+	Adapter for json11 parser library
+
+shsfre09 (github username), <email address unknown>
+	Adapter for picojson parser library
+
+Michael Smith, michael.smith@puppetlabs.com
+	Memory management improvements for RapidJson parser library
+
+Richard Clamp, richardc@unixbeard.net
+	Boost-related fixes
+
+Lars Immisch, lars@ibp.de
+	noboost branch
+
+Nicolas Witczak, n_witczak@yahoo.com
+	C++11 improvements
+
+Martin Robinson, 0x4d52@gmail.com
+	Bug fixes
+
+Pierre Lamot, pierre.lamot@yahoo.fr
+	Adapter for Qt JSON parser
+
+drewxa (github username), bo.ro.da@mail.ru
+	Adapter for Poco JSON parser
+
+Jordan Bayles (jophba), jophba@chromium.org
+	JsonCpp owner
diff --git a/subprojects/valijson/LICENSE b/subprojects/valijson/LICENSE
new file mode 100644
index 000000000..77d38164c
--- /dev/null
+++ b/subprojects/valijson/LICENSE
@@ -0,0 +1,23 @@
+Copyright (c) 2016, Tristan Penman
+Copyright (c) 2016, Akamai Technolgies, Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/subprojects/valijson/include/compat/optional.hpp b/subprojects/valijson/include/compat/optional.hpp
new file mode 100644
index 000000000..b0182dfbf
--- /dev/null
+++ b/subprojects/valijson/include/compat/optional.hpp
@@ -0,0 +1,1043 @@
+// Copyright (C) 2011 - 2012 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// The idea and interface is based on Boost.Optional library
+// authored by Fernando Luis Cacciola Carballal
+
+# ifndef ___OPTIONAL_HPP___
+# define ___OPTIONAL_HPP___
+
+# include <utility>
+# include <type_traits>
+# include <initializer_list>
+# include <cassert>
+# include <functional>
+# include <string>
+# include <stdexcept>
+# include <valijson/exceptions.hpp>
+
+# define TR2_OPTIONAL_REQUIRES(...) typename enable_if<__VA_ARGS__::value, bool>::type = false
+
+# if defined __GNUC__ // NOTE: GNUC is also defined for Clang
+#   if (__GNUC__ == 4) && (__GNUC_MINOR__ >= 8)
+#     define TR2_OPTIONAL_GCC_4_8_AND_HIGHER___
+#   elif (__GNUC__ > 4)
+#     define TR2_OPTIONAL_GCC_4_8_AND_HIGHER___
+#   endif
+#
+#   if (__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)
+#     define TR2_OPTIONAL_GCC_4_7_AND_HIGHER___
+#   elif (__GNUC__ > 4)
+#     define TR2_OPTIONAL_GCC_4_7_AND_HIGHER___
+#   endif
+#
+#   if (__GNUC__ == 4) && (__GNUC_MINOR__ == 8) && (__GNUC_PATCHLEVEL__ >= 1)
+#     define TR2_OPTIONAL_GCC_4_8_1_AND_HIGHER___
+#   elif (__GNUC__ == 4) && (__GNUC_MINOR__ >= 9)
+#     define TR2_OPTIONAL_GCC_4_8_1_AND_HIGHER___
+#   elif (__GNUC__ > 4)
+#     define TR2_OPTIONAL_GCC_4_8_1_AND_HIGHER___
+#   endif
+# endif
+#
+# if defined __clang_major__
+#   if (__clang_major__ == 3 && __clang_minor__ >= 5)
+#     define TR2_OPTIONAL_CLANG_3_5_AND_HIGHTER_
+#   elif (__clang_major__ > 3)
+#     define TR2_OPTIONAL_CLANG_3_5_AND_HIGHTER_
+#   endif
+#   if defined TR2_OPTIONAL_CLANG_3_5_AND_HIGHTER_
+#     define TR2_OPTIONAL_CLANG_3_4_2_AND_HIGHER_
+#   elif (__clang_major__ == 3 && __clang_minor__ == 4 && __clang_patchlevel__ >= 2)
+#     define TR2_OPTIONAL_CLANG_3_4_2_AND_HIGHER_
+#   endif
+# endif
+#
+# if defined _MSC_VER
+#   if (_MSC_VER >= 1900)
+#     define TR2_OPTIONAL_MSVC_2015_AND_HIGHER___
+#   endif
+# endif
+
+# if defined __clang__
+#   if (__clang_major__ > 2) || (__clang_major__ == 2) && (__clang_minor__ >= 9)
+#     define OPTIONAL_HAS_THIS_RVALUE_REFS 1
+#   else
+#     define OPTIONAL_HAS_THIS_RVALUE_REFS 0
+#   endif
+# elif defined TR2_OPTIONAL_GCC_4_8_1_AND_HIGHER___
+#   define OPTIONAL_HAS_THIS_RVALUE_REFS 1
+# elif defined TR2_OPTIONAL_MSVC_2015_AND_HIGHER___
+#   define OPTIONAL_HAS_THIS_RVALUE_REFS 1
+# else
+#   define OPTIONAL_HAS_THIS_RVALUE_REFS 0
+# endif
+
+
+# if defined TR2_OPTIONAL_GCC_4_8_1_AND_HIGHER___
+#   define OPTIONAL_HAS_CONSTEXPR_INIT_LIST 1
+#   define OPTIONAL_CONSTEXPR_INIT_LIST constexpr
+# else
+#   define OPTIONAL_HAS_CONSTEXPR_INIT_LIST 0
+#   define OPTIONAL_CONSTEXPR_INIT_LIST
+# endif
+
+# if defined TR2_OPTIONAL_CLANG_3_5_AND_HIGHTER_ && (defined __cplusplus) && (__cplusplus != 201103L)
+#   define OPTIONAL_HAS_MOVE_ACCESSORS 1
+# else
+#   define OPTIONAL_HAS_MOVE_ACCESSORS 0
+# endif
+
+# // In C++11 constexpr implies const, so we need to make non-const members also non-constexpr
+# if (defined __cplusplus) && (__cplusplus == 201103L)
+#   define OPTIONAL_MUTABLE_CONSTEXPR
+# else
+#   define OPTIONAL_MUTABLE_CONSTEXPR constexpr
+# endif
+
+namespace std{
+
+    namespace experimental{
+
+        // BEGIN workaround for missing is_trivially_destructible
+# if defined TR2_OPTIONAL_GCC_4_8_AND_HIGHER___
+        // leave it: it is already there
+# elif defined TR2_OPTIONAL_CLANG_3_4_2_AND_HIGHER_
+        // leave it: it is already there
+# elif defined TR2_OPTIONAL_MSVC_2015_AND_HIGHER___
+        // leave it: it is already there
+# elif defined TR2_OPTIONAL_DISABLE_EMULATION_OF_TYPE_TRAITS
+        // leave it: the user doesn't want it
+# else
+        template <typename T>
+        using is_trivially_destructible = std::has_trivial_destructor<T>;
+# endif
+        // END workaround for missing is_trivially_destructible
+
+# if (defined TR2_OPTIONAL_GCC_4_7_AND_HIGHER___)
+        // leave it; our metafunctions are already defined.
+# elif defined TR2_OPTIONAL_CLANG_3_4_2_AND_HIGHER_
+        // leave it; our metafunctions are already defined.
+# elif defined TR2_OPTIONAL_MSVC_2015_AND_HIGHER___
+        // leave it: it is already there
+# elif defined TR2_OPTIONAL_DISABLE_EMULATION_OF_TYPE_TRAITS
+        // leave it: the user doesn't want it
+# else
+
+
+        // workaround for missing traits in GCC and CLANG
+        template <class T>
+        struct is_nothrow_move_constructible
+        {
+            constexpr static bool value = std::is_nothrow_constructible<T, T&&>::value;
+        };
+
+
+        template <class T, class U>
+        struct is_assignable
+        {
+            template <class X, class Y>
+            constexpr static bool has_assign(...) { return false; }
+
+            template <class X, class Y, size_t S = sizeof((std::declval<X>() = std::declval<Y>(), true)) >
+            // the comma operator is necessary for the cases where operator= returns void
+            constexpr static bool has_assign(bool) { return true; }
+
+            constexpr static bool value = has_assign<T, U>(true);
+        };
+
+
+        template <class T>
+        struct is_nothrow_move_assignable
+        {
+            template <class X, bool has_any_move_assign>
+            struct has_nothrow_move_assign {
+    constexpr static bool value = false;
+            };
+
+            template <class X>
+            struct has_nothrow_move_assign<X, true> {
+    constexpr static bool value = noexcept( std::declval<X&>() = std::declval<X&&>() );
+            };
+
+            constexpr static bool value = has_nothrow_move_assign<T, is_assignable<T&, T&&>::value>::value;
+        };
+        // end workaround
+
+
+# endif
+
+
+
+        // 20.5.4, optional for object types
+        template <class T> class optional;
+
+        // 20.5.5, optional for lvalue reference types
+        template <class T> class optional<T&>;
+
+
+        // workaround: std utility functions aren't constexpr yet
+        template <class T> inline constexpr T&& constexpr_forward(typename std::remove_reference<T>::type& t) noexcept
+        {
+            return static_cast<T&&>(t);
+        }
+
+        template <class T> inline constexpr T&& constexpr_forward(typename std::remove_reference<T>::type&& t) noexcept
+        {
+            static_assert(!std::is_lvalue_reference<T>::value, "!!");
+            return static_cast<T&&>(t);
+        }
+
+        template <class T> inline constexpr typename std::remove_reference<T>::type&& constexpr_move(T&& t) noexcept
+        {
+            return static_cast<typename std::remove_reference<T>::type&&>(t);
+        }
+
+
+#if defined NDEBUG
+# define TR2_OPTIONAL_ASSERTED_EXPRESSION(CHECK, EXPR) (EXPR)
+#else
+# define TR2_OPTIONAL_ASSERTED_EXPRESSION(CHECK, EXPR) ((CHECK) ? (EXPR) : ([]{assert(!#CHECK);}(), (EXPR)))
+#endif
+
+
+        namespace detail_
+        {
+
+            // static_addressof: a constexpr version of addressof
+            template <typename T>
+            struct has_overloaded_addressof
+            {
+                template <class X>
+                constexpr static bool has_overload(...) { return false; }
+
+                template <class X, size_t S = sizeof(std::declval<X&>().operator&()) >
+                constexpr static bool has_overload(bool) { return true; }
+
+                constexpr static bool value = has_overload<T>(true);
+            };
+
+            template <typename T, TR2_OPTIONAL_REQUIRES(!has_overloaded_addressof<T>)>
+            constexpr T* static_addressof(T& ref)
+            {
+                return &ref;
+            }
+
+            template <typename T, TR2_OPTIONAL_REQUIRES(has_overloaded_addressof<T>)>
+            T* static_addressof(T& ref)
+            {
+                return std::addressof(ref);
+            }
+
+
+            // the call to convert<A>(b) has return type A and converts b to type A iff b decltype(b) is implicitly convertible to A
+            template <class U>
+            constexpr U convert(U v) { return v; }
+
+        } // namespace detail
+
+
+        constexpr struct trivial_init_t{} trivial_init{};
+
+
+        // 20.5.6, In-place construction
+        constexpr struct in_place_t{} in_place{};
+
+
+        // 20.5.7, Disengaged state indicator
+        struct nullopt_t
+        {
+            struct init{};
+            constexpr explicit nullopt_t(init){}
+        };
+        constexpr nullopt_t nullopt{nullopt_t::init()};
+
+
+        // 20.5.8, class bad_optional_access
+        class bad_optional_access : public logic_error {
+        public:
+            explicit bad_optional_access(const string& what_arg) : logic_error{what_arg} {}
+            explicit bad_optional_access(const char* what_arg) : logic_error{what_arg} {}
+        };
+
+
+        template <class T>
+        union storage_t
+        {
+            unsigned char dummy_;
+            T value_;
+
+            constexpr storage_t( trivial_init_t ) noexcept : dummy_() {};
+
+            template <class... Args>
+            constexpr storage_t( Args&&... args ) : value_(constexpr_forward<Args>(args)...) {}
+
+            ~storage_t(){}
+        };
+
+
+        template <class T>
+        union constexpr_storage_t
+        {
+            unsigned char dummy_;
+            T value_;
+
+            constexpr constexpr_storage_t( trivial_init_t ) noexcept : dummy_() {};
+
+            template <class... Args>
+            constexpr constexpr_storage_t( Args&&... args ) : value_(constexpr_forward<Args>(args)...) {}
+
+            ~constexpr_storage_t() = default;
+        };
+
+
+        template <class T>
+        struct optional_base
+        {
+            bool init_;
+            storage_t<T> storage_;
+
+            constexpr optional_base() noexcept : init_(false), storage_(trivial_init) {};
+
+            explicit constexpr optional_base(const T& v) : init_(true), storage_(v) {}
+
+            explicit constexpr optional_base(T&& v) : init_(true), storage_(constexpr_move(v)) {}
+
+            template <class... Args> explicit optional_base(in_place_t, Args&&... args)
+            : init_(true), storage_(constexpr_forward<Args>(args)...) {}
+
+            template <class U, class... Args, TR2_OPTIONAL_REQUIRES(is_constructible<T, std::initializer_list<U>>)>
+            explicit optional_base(in_place_t, std::initializer_list<U> il, Args&&... args)
+            : init_(true), storage_(il, std::forward<Args>(args)...) {}
+
+            ~optional_base() { if (init_) storage_.value_.T::~T(); }
+        };
+
+
+        template <class T>
+        struct constexpr_optional_base
+        {
+            bool init_;
+            constexpr_storage_t<T> storage_;
+
+            constexpr constexpr_optional_base() noexcept : init_(false), storage_(trivial_init) {};
+
+            explicit constexpr constexpr_optional_base(const T& v) : init_(true), storage_(v) {}
+
+            explicit constexpr constexpr_optional_base(T&& v) : init_(true), storage_(constexpr_move(v)) {}
+
+            template <class... Args> explicit constexpr constexpr_optional_base(in_place_t, Args&&... args)
+            : init_(true), storage_(constexpr_forward<Args>(args)...) {}
+
+            template <class U, class... Args, TR2_OPTIONAL_REQUIRES(is_constructible<T, std::initializer_list<U>>)>
+            OPTIONAL_CONSTEXPR_INIT_LIST explicit constexpr_optional_base(in_place_t, std::initializer_list<U> il, Args&&... args)
+            : init_(true), storage_(il, std::forward<Args>(args)...) {}
+
+            ~constexpr_optional_base() = default;
+        };
+
+        template <class T>
+        using OptionalBase = typename std::conditional<
+        is_trivially_destructible<T>::value,
+        constexpr_optional_base<typename std::remove_const<T>::type>,
+        optional_base<typename std::remove_const<T>::type>
+        >::type;
+
+
+
+        template <class T>
+        class optional : private OptionalBase<T>
+        {
+            static_assert( !std::is_same<typename std::decay<T>::type, nullopt_t>::value, "bad T" );
+            static_assert( !std::is_same<typename std::decay<T>::type, in_place_t>::value, "bad T" );
+
+
+            constexpr bool initialized() const noexcept { return OptionalBase<T>::init_; }
+            typename std::remove_const<T>::type* dataptr() {  return std::addressof(OptionalBase<T>::storage_.value_); }
+            constexpr const T* dataptr() const { return detail_::static_addressof(OptionalBase<T>::storage_.value_); }
+
+# if OPTIONAL_HAS_THIS_RVALUE_REFS == 1
+            constexpr const T& contained_val() const& { return OptionalBase<T>::storage_.value_; }
+#   if OPTIONAL_HAS_MOVE_ACCESSORS == 1
+            OPTIONAL_MUTABLE_CONSTEXPR T&& contained_val() && { return std::move(OptionalBase<T>::storage_.value_); }
+            OPTIONAL_MUTABLE_CONSTEXPR T& contained_val() & { return OptionalBase<T>::storage_.value_; }
+#   else
+            T& contained_val() & { return OptionalBase<T>::storage_.value_; }
+            T&& contained_val() && { return std::move(OptionalBase<T>::storage_.value_); }
+#   endif
+# else
+            constexpr const T& contained_val() const { return OptionalBase<T>::storage_.value_; }
+            T& contained_val() { return OptionalBase<T>::storage_.value_; }
+# endif
+
+            void clear() noexcept {
+    if (initialized()) dataptr()->T::~T();
+    OptionalBase<T>::init_ = false;
+            }
+
+            template <class... Args>
+            void initialize(Args&&... args) noexcept(noexcept(T(std::forward<Args>(args)...)))
+            {
+    assert(!OptionalBase<T>::init_);
+    ::new (static_cast<void*>(dataptr())) T(std::forward<Args>(args)...);
+    OptionalBase<T>::init_ = true;
+            }
+
+            template <class U, class... Args>
+            void initialize(std::initializer_list<U> il, Args&&... args) noexcept(noexcept(T(il, std::forward<Args>(args)...)))
+            {
+    assert(!OptionalBase<T>::init_);
+    ::new (static_cast<void*>(dataptr())) T(il, std::forward<Args>(args)...);
+    OptionalBase<T>::init_ = true;
+            }
+
+        public:
+            typedef T value_type;
+
+            // 20.5.5.1, constructors
+            constexpr optional() noexcept : OptionalBase<T>()  {};
+            constexpr optional(nullopt_t) noexcept : OptionalBase<T>() {};
+
+            optional(const optional& rhs)
+            : OptionalBase<T>()
+            {
+    if (rhs.initialized()) {
+        ::new (static_cast<void*>(dataptr())) T(*rhs);
+        OptionalBase<T>::init_ = true;
+    }
+            }
+
+            optional(optional&& rhs) noexcept(is_nothrow_move_constructible<T>::value)
+            : OptionalBase<T>()
+            {
+    if (rhs.initialized()) {
+        ::new (static_cast<void*>(dataptr())) T(std::move(*rhs));
+        OptionalBase<T>::init_ = true;
+    }
+            }
+
+            constexpr optional(const T& v) : OptionalBase<T>(v) {}
+
+            constexpr optional(T&& v) : OptionalBase<T>(constexpr_move(v)) {}
+
+            template <class... Args>
+            explicit constexpr optional(in_place_t, Args&&... args)
+            : OptionalBase<T>(in_place_t{}, constexpr_forward<Args>(args)...) {}
+
+            template <class U, class... Args, TR2_OPTIONAL_REQUIRES(is_constructible<T, std::initializer_list<U>>)>
+            OPTIONAL_CONSTEXPR_INIT_LIST explicit optional(in_place_t, std::initializer_list<U> il, Args&&... args)
+            : OptionalBase<T>(in_place_t{}, il, constexpr_forward<Args>(args)...) {}
+
+            // 20.5.4.2, Destructor
+            ~optional() = default;
+
+            // 20.5.4.3, assignment
+            optional& operator=(nullopt_t) noexcept
+            {
+    clear();
+    return *this;
+            }
+
+            optional& operator=(const optional& rhs)
+            {
+    if      (initialized() == true  && rhs.initialized() == false) clear();
+    else if (initialized() == false && rhs.initialized() == true)  initialize(*rhs);
+    else if (initialized() == true  && rhs.initialized() == true)  contained_val() = *rhs;
+    return *this;
+            }
+
+            optional& operator=(optional&& rhs)
+            noexcept(is_nothrow_move_assignable<T>::value && is_nothrow_move_constructible<T>::value)
+            {
+    if      (initialized() == true  && rhs.initialized() == false) clear();
+        else if (initialized() == false && rhs.initialized() == true)  initialize(std::move(*rhs));
+            else if (initialized() == true  && rhs.initialized() == true)  contained_val() = std::move(*rhs);
+    return *this;
+            }
+
+            template <class U>
+            auto operator=(U&& v)
+            -> typename enable_if
+            <
+            is_same<typename decay<U>::type, T>::value,
+            optional&
+            >::type
+            {
+    if (initialized()) { contained_val() = std::forward<U>(v); }
+    else               { initialize(std::forward<U>(v));  }
+    return *this;
+            }
+
+
+            template <class... Args>
+            void emplace(Args&&... args)
+            {
+    clear();
+    initialize(std::forward<Args>(args)...);
+            }
+
+            template <class U, class... Args>
+            void emplace(initializer_list<U> il, Args&&... args)
+            {
+    clear();
+    initialize<U, Args...>(il, std::forward<Args>(args)...);
+            }
+
+            // 20.5.4.4, Swap
+            void swap(optional<T>& rhs) noexcept(is_nothrow_move_constructible<T>::value && noexcept(swap(declval<T&>(), declval<T&>())))
+            {
+    if      (initialized() == true  && rhs.initialized() == false) { rhs.initialize(std::move(**this)); clear(); }
+    else if (initialized() == false && rhs.initialized() == true)  { initialize(std::move(*rhs)); rhs.clear(); }
+    else if (initialized() == true  && rhs.initialized() == true)  { using std::swap; swap(**this, *rhs); }
+            }
+
+            // 20.5.4.5, Observers
+
+            explicit constexpr operator bool() const noexcept { return initialized(); }
+
+            constexpr T const* operator ->() const {
+    return TR2_OPTIONAL_ASSERTED_EXPRESSION(initialized(), dataptr());
+            }
+
+# if OPTIONAL_HAS_MOVE_ACCESSORS == 1
+
+            OPTIONAL_MUTABLE_CONSTEXPR T* operator ->() {
+    assert (initialized());
+    return dataptr();
+            }
+
+            constexpr T const& operator *() const& {
+    return TR2_OPTIONAL_ASSERTED_EXPRESSION(initialized(), contained_val());
+            }
+
+            OPTIONAL_MUTABLE_CONSTEXPR T& operator *() & {
+    assert (initialized());
+    return contained_val();
+            }
+
+            OPTIONAL_MUTABLE_CONSTEXPR T&& operator *() && {
+    assert (initialized());
+    return constexpr_move(contained_val());
+            }
+
+            constexpr T const& value() const& {
+    return initialized() ? contained_val() : (valijson::throwRuntimeError("bad optional access"), contained_val());
+            }
+
+            OPTIONAL_MUTABLE_CONSTEXPR T& value() & {
+    return initialized() ? contained_val() : (valijson::throwRuntimeError("bad optional access"), contained_val());
+            }
+
+            OPTIONAL_MUTABLE_CONSTEXPR T&& value() && {
+    if (!initialized()) valijson::throwRuntimeError("bad optional access");
+        return std::move(contained_val());
+            }
+
+# else
+
+            T* operator ->() {
+    assert (initialized());
+    return dataptr();
+            }
+
+            constexpr T const& operator *() const {
+    return TR2_OPTIONAL_ASSERTED_EXPRESSION(initialized(), contained_val());
+            }
+
+            T& operator *() {
+    assert (initialized());
+    return contained_val();
+            }
+
+            constexpr T const& value() const {
+    return initialized() ? contained_val() : (valijson::throwRuntimeError("bad optional access"), contained_val());
+            }
+
+            T& value() {
+    return initialized() ? contained_val() : (valijson::throwRuntimeError("bad optional access"), contained_val());
+            }
+
+# endif
+
+# if OPTIONAL_HAS_THIS_RVALUE_REFS == 1
+
+            template <class V>
+            constexpr T value_or(V&& v) const&
+            {
+    return *this ? **this : detail_::convert<T>(constexpr_forward<V>(v));
+            }
+
+#   if OPTIONAL_HAS_MOVE_ACCESSORS == 1
+
+            template <class V>
+            OPTIONAL_MUTABLE_CONSTEXPR T value_or(V&& v) &&
+            {
+    return *this ? constexpr_move(const_cast<optional<T>&>(*this).contained_val()) : detail_::convert<T>(constexpr_forward<V>(v));
+            }
+
+#   else
+
+            template <class V>
+            T value_or(V&& v) &&
+            {
+    return *this ? constexpr_move(const_cast<optional<T>&>(*this).contained_val()) : detail_::convert<T>(constexpr_forward<V>(v));
+            }
+
+#   endif
+
+# else
+
+            template <class V>
+            constexpr T value_or(V&& v) const
+            {
+    return *this ? **this : detail_::convert<T>(constexpr_forward<V>(v));
+            }
+
+# endif
+
+        };
+
+
+        template <class T>
+        class optional<T&>
+        {
+            static_assert( !std::is_same<T, nullopt_t>::value, "bad T" );
+            static_assert( !std::is_same<T, in_place_t>::value, "bad T" );
+            T* ref;
+
+        public:
+
+            // 20.5.5.1, construction/destruction
+            constexpr optional() noexcept : ref(nullptr) {}
+
+            constexpr optional(nullopt_t) noexcept : ref(nullptr) {}
+
+            constexpr optional(T& v) noexcept : ref(detail_::static_addressof(v)) {}
+
+            optional(T&&) = delete;
+
+            constexpr optional(const optional& rhs) noexcept : ref(rhs.ref) {}
+
+            explicit constexpr optional(in_place_t, T& v) noexcept : ref(detail_::static_addressof(v)) {}
+
+            explicit optional(in_place_t, T&&) = delete;
+
+            ~optional() = default;
+
+            // 20.5.5.2, mutation
+            optional& operator=(nullopt_t) noexcept {
+    ref = nullptr;
+    return *this;
+            }
+
+            // optional& operator=(const optional& rhs) noexcept {
+            // ref = rhs.ref;
+            // return *this;
+            // }
+
+            // optional& operator=(optional&& rhs) noexcept {
+            // ref = rhs.ref;
+            // return *this;
+            // }
+
+            template <typename U>
+            auto operator=(U&& rhs) noexcept
+            -> typename enable_if
+            <
+            is_same<typename decay<U>::type, optional<T&>>::value,
+            optional&
+            >::type
+            {
+    ref = rhs.ref;
+    return *this;
+            }
+
+            template <typename U>
+            auto operator=(U&& rhs) noexcept
+            -> typename enable_if
+            <
+            !is_same<typename decay<U>::type, optional<T&>>::value,
+            optional&
+            >::type
+            = delete;
+
+            void emplace(T& v) noexcept {
+    ref = detail_::static_addressof(v);
+            }
+
+            void emplace(T&&) = delete;
+
+
+            void swap(optional<T&>& rhs) noexcept
+            {
+    std::swap(ref, rhs.ref);
+            }
+
+            // 20.5.5.3, observers
+            constexpr T* operator->() const {
+    return TR2_OPTIONAL_ASSERTED_EXPRESSION(ref, ref);
+            }
+
+            constexpr T& operator*() const {
+    return TR2_OPTIONAL_ASSERTED_EXPRESSION(ref, *ref);
+            }
+
+            constexpr T& value() const {
+    return ref ? *ref : (valijson::throwRuntimeError("bad optional access"), *ref);
+            }
+
+            explicit constexpr operator bool() const noexcept {
+    return ref != nullptr;
+            }
+
+            template <class V>
+            constexpr typename decay<T>::type value_or(V&& v) const
+            {
+    return *this ? **this : detail_::convert<typename decay<T>::type>(constexpr_forward<V>(v));
+            }
+        };
+
+
+        template <class T>
+        class optional<T&&>
+        {
+            static_assert( sizeof(T) == 0, "optional rvalue references disallowed" );
+        };
+
+
+        // 20.5.8, Relational operators
+        template <class T> constexpr bool operator==(const optional<T>& x, const optional<T>& y)
+        {
+            return bool(x) != bool(y) ? false : bool(x) == false ? true : *x == *y;
+        }
+
+        template <class T> constexpr bool operator!=(const optional<T>& x, const optional<T>& y)
+        {
+            return !(x == y);
+        }
+
+        template <class T> constexpr bool operator<(const optional<T>& x, const optional<T>& y)
+        {
+            return (!y) ? false : (!x) ? true : *x < *y;
+        }
+
+        template <class T> constexpr bool operator>(const optional<T>& x, const optional<T>& y)
+        {
+            return (y < x);
+        }
+
+        template <class T> constexpr bool operator<=(const optional<T>& x, const optional<T>& y)
+        {
+            return !(y < x);
+        }
+
+        template <class T> constexpr bool operator>=(const optional<T>& x, const optional<T>& y)
+        {
+            return !(x < y);
+        }
+
+
+        // 20.5.9, Comparison with nullopt
+        template <class T> constexpr bool operator==(const optional<T>& x, nullopt_t) noexcept
+        {
+            return (!x);
+        }
+
+        template <class T> constexpr bool operator==(nullopt_t, const optional<T>& x) noexcept
+        {
+            return (!x);
+        }
+
+        template <class T> constexpr bool operator!=(const optional<T>& x, nullopt_t) noexcept
+        {
+            return bool(x);
+        }
+
+        template <class T> constexpr bool operator!=(nullopt_t, const optional<T>& x) noexcept
+        {
+            return bool(x);
+        }
+
+        template <class T> constexpr bool operator<(const optional<T>&, nullopt_t) noexcept
+        {
+            return false;
+        }
+
+        template <class T> constexpr bool operator<(nullopt_t, const optional<T>& x) noexcept
+        {
+            return bool(x);
+        }
+
+        template <class T> constexpr bool operator<=(const optional<T>& x, nullopt_t) noexcept
+        {
+            return (!x);
+        }
+
+        template <class T> constexpr bool operator<=(nullopt_t, const optional<T>&) noexcept
+        {
+            return true;
+        }
+
+        template <class T> constexpr bool operator>(const optional<T>& x, nullopt_t) noexcept
+        {
+            return bool(x);
+        }
+
+        template <class T> constexpr bool operator>(nullopt_t, const optional<T>&) noexcept
+        {
+            return false;
+        }
+
+        template <class T> constexpr bool operator>=(const optional<T>&, nullopt_t) noexcept
+        {
+            return true;
+        }
+
+        template <class T> constexpr bool operator>=(nullopt_t, const optional<T>& x) noexcept
+        {
+            return (!x);
+        }
+
+
+
+        // 20.5.10, Comparison with T
+        template <class T> constexpr bool operator==(const optional<T>& x, const T& v)
+        {
+            return bool(x) ? *x == v : false;
+        }
+
+        template <class T> constexpr bool operator==(const T& v, const optional<T>& x)
+        {
+            return bool(x) ? v == *x : false;
+        }
+
+        template <class T> constexpr bool operator!=(const optional<T>& x, const T& v)
+        {
+            return bool(x) ? *x != v : true;
+        }
+
+        template <class T> constexpr bool operator!=(const T& v, const optional<T>& x)
+        {
+            return bool(x) ? v != *x : true;
+        }
+
+        template <class T> constexpr bool operator<(const optional<T>& x, const T& v)
+        {
+            return bool(x) ? *x < v : true;
+        }
+
+        template <class T> constexpr bool operator>(const T& v, const optional<T>& x)
+        {
+            return bool(x) ? v > *x : true;
+        }
+
+        template <class T> constexpr bool operator>(const optional<T>& x, const T& v)
+        {
+            return bool(x) ? *x > v : false;
+        }
+
+        template <class T> constexpr bool operator<(const T& v, const optional<T>& x)
+        {
+            return bool(x) ? v < *x : false;
+        }
+
+        template <class T> constexpr bool operator>=(const optional<T>& x, const T& v)
+        {
+            return bool(x) ? *x >= v : false;
+        }
+
+        template <class T> constexpr bool operator<=(const T& v, const optional<T>& x)
+        {
+            return bool(x) ? v <= *x : false;
+        }
+
+        template <class T> constexpr bool operator<=(const optional<T>& x, const T& v)
+        {
+            return bool(x) ? *x <= v : true;
+        }
+
+        template <class T> constexpr bool operator>=(const T& v, const optional<T>& x)
+        {
+            return bool(x) ? v >= *x : true;
+        }
+
+
+        // Comparison of optional<T&> with T
+        template <class T> constexpr bool operator==(const optional<T&>& x, const T& v)
+        {
+            return bool(x) ? *x == v : false;
+        }
+
+        template <class T> constexpr bool operator==(const T& v, const optional<T&>& x)
+        {
+            return bool(x) ? v == *x : false;
+        }
+
+        template <class T> constexpr bool operator!=(const optional<T&>& x, const T& v)
+        {
+            return bool(x) ? *x != v : true;
+        }
+
+        template <class T> constexpr bool operator!=(const T& v, const optional<T&>& x)
+        {
+            return bool(x) ? v != *x : true;
+        }
+
+        template <class T> constexpr bool operator<(const optional<T&>& x, const T& v)
+        {
+            return bool(x) ? *x < v : true;
+        }
+
+        template <class T> constexpr bool operator>(const T& v, const optional<T&>& x)
+        {
+            return bool(x) ? v > *x : true;
+        }
+
+        template <class T> constexpr bool operator>(const optional<T&>& x, const T& v)
+        {
+            return bool(x) ? *x > v : false;
+        }
+
+        template <class T> constexpr bool operator<(const T& v, const optional<T&>& x)
+        {
+            return bool(x) ? v < *x : false;
+        }
+
+        template <class T> constexpr bool operator>=(const optional<T&>& x, const T& v)
+        {
+            return bool(x) ? *x >= v : false;
+        }
+
+        template <class T> constexpr bool operator<=(const T& v, const optional<T&>& x)
+        {
+            return bool(x) ? v <= *x : false;
+        }
+
+        template <class T> constexpr bool operator<=(const optional<T&>& x, const T& v)
+        {
+            return bool(x) ? *x <= v : true;
+        }
+
+        template <class T> constexpr bool operator>=(const T& v, const optional<T&>& x)
+        {
+            return bool(x) ? v >= *x : true;
+        }
+
+        // Comparison of optional<T const&> with T
+        template <class T> constexpr bool operator==(const optional<const T&>& x, const T& v)
+        {
+            return bool(x) ? *x == v : false;
+        }
+
+        template <class T> constexpr bool operator==(const T& v, const optional<const T&>& x)
+        {
+            return bool(x) ? v == *x : false;
+        }
+
+        template <class T> constexpr bool operator!=(const optional<const T&>& x, const T& v)
+        {
+            return bool(x) ? *x != v : true;
+        }
+
+        template <class T> constexpr bool operator!=(const T& v, const optional<const T&>& x)
+        {
+            return bool(x) ? v != *x : true;
+        }
+
+        template <class T> constexpr bool operator<(const optional<const T&>& x, const T& v)
+        {
+            return bool(x) ? *x < v : true;
+        }
+
+        template <class T> constexpr bool operator>(const T& v, const optional<const T&>& x)
+        {
+            return bool(x) ? v > *x : true;
+        }
+
+        template <class T> constexpr bool operator>(const optional<const T&>& x, const T& v)
+        {
+            return bool(x) ? *x > v : false;
+        }
+
+        template <class T> constexpr bool operator<(const T& v, const optional<const T&>& x)
+        {
+            return bool(x) ? v < *x : false;
+        }
+
+        template <class T> constexpr bool operator>=(const optional<const T&>& x, const T& v)
+        {
+            return bool(x) ? *x >= v : false;
+        }
+
+        template <class T> constexpr bool operator<=(const T& v, const optional<const T&>& x)
+        {
+            return bool(x) ? v <= *x : false;
+        }
+
+        template <class T> constexpr bool operator<=(const optional<const T&>& x, const T& v)
+        {
+            return bool(x) ? *x <= v : true;
+        }
+
+        template <class T> constexpr bool operator>=(const T& v, const optional<const T&>& x)
+        {
+            return bool(x) ? v >= *x : true;
+        }
+
+
+        // 20.5.12, Specialized algorithms
+        template <class T>
+        void swap(optional<T>& x, optional<T>& y) noexcept(noexcept(x.swap(y)))
+        {
+            x.swap(y);
+        }
+
+
+        template <class T>
+        constexpr optional<typename decay<T>::type> make_optional(T&& v)
+        {
+            return optional<typename decay<T>::type>(constexpr_forward<T>(v));
+        }
+
+        template <class X>
+        constexpr optional<X&> make_optional(reference_wrapper<X> v)
+        {
+            return optional<X&>(v.get());
+        }
+
+
+    } // namespace experimental
+} // namespace std
+
+namespace std
+{
+    template <typename T>
+    struct hash<std::experimental::optional<T>>
+    {
+        typedef typename hash<T>::result_type result_type;
+        typedef std::experimental::optional<T> argument_type;
+
+        constexpr result_type operator()(argument_type const& arg) const {
+            return arg ? std::hash<T>{}(*arg) : result_type{};
+        }
+    };
+
+    template <typename T>
+    struct hash<std::experimental::optional<T&>>
+    {
+        typedef typename hash<T>::result_type result_type;
+        typedef std::experimental::optional<T&> argument_type;
+
+        constexpr result_type operator()(argument_type const& arg) const {
+            return arg ? std::hash<T>{}(*arg) : result_type{};
+        }
+    };
+}
+
+# undef TR2_OPTIONAL_REQUIRES
+# undef TR2_OPTIONAL_ASSERTED_EXPRESSION
+
+# endif //___OPTIONAL_HPP___
diff --git a/subprojects/valijson/include/valijson/adapters/adapter.hpp b/subprojects/valijson/include/valijson/adapters/adapter.hpp
new file mode 100644
index 000000000..146156b50
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/adapter.hpp
@@ -0,0 +1,472 @@
+#pragma once
+
+#include <functional>
+
+namespace valijson {
+namespace adapters {
+
+class FrozenValue;
+
+/**
+ * @brief   An interface that encapsulates access to the JSON values provided
+ *          by a JSON parser implementation.
+ *
+ * This interface allows JSON processing code to be parser-agnostic. It provides
+ * functions to access the plain old datatypes (PODs) that are described in the
+ * JSON specification, and callback-based access to the contents of arrays and
+ * objects.
+ *
+ * The interface also defines a set of functions that allow for type-casting and
+ * type-comparison based on value rather than on type.
+ */
+class Adapter
+{
+public:
+
+    /// Typedef for callback function supplied to applyToArray.
+    typedef std::function<bool (const Adapter &)>
+        ArrayValueCallback;
+
+    /// Typedef for callback function supplied to applyToObject.
+    typedef std::function<bool (const std::string &, const Adapter &)>
+        ObjectMemberCallback;
+
+    /**
+     * @brief   Virtual destructor defined to ensure deletion via base-class
+     *          pointers is safe.
+     */
+    virtual ~Adapter() = default;
+
+    /**
+     * @brief   Apply a callback function to each value in an array.
+     *
+     * The callback function is invoked for each element in the array, until
+     * it has been applied to all values, or it returns false.
+     *
+     * @param   fn  Callback function to invoke
+     *
+     * @returns true if Adapter contains an array and all values are equal,
+     *          false otherwise.
+     */
+    virtual bool applyToArray(ArrayValueCallback fn) const = 0;
+
+    /**
+     * @brief   Apply a callback function to each member in an object.
+     *
+     * The callback function shall be invoked for each member in the object,
+     * until it has been applied to all values, or it returns false.
+     *
+     * @param   fn  Callback function to invoke
+     *
+     * @returns true if Adapter contains an object, and callback function
+     *          returns true for each member in the object, false otherwise.
+     */
+    virtual bool applyToObject(ObjectMemberCallback fn) const = 0;
+
+    /**
+     * @brief   Return the boolean representation of the contained value.
+     *
+     * This function shall return a boolean value if the Adapter contains either
+     * an actual boolean value, or one of the strings 'true' or 'false'.
+     * The string comparison is case sensitive.
+     *
+     * An exception shall be thrown if the value cannot be cast to a boolean.
+     *
+     * @returns  Boolean representation of contained value.
+     */
+    virtual bool asBool() const = 0;
+
+    /**
+     * @brief   Retrieve the boolean representation of the contained value.
+     *
+     * This function shall retrieve a boolean value if the Adapter contains
+     * either an actual boolean value, or one of the strings 'true' or 'false'.
+     * The string comparison is case sensitive.
+     *
+     * The retrieved value is returned via reference.
+     *
+     * @param   result  reference to a bool to set with retrieved value.
+     *
+     * @returns true if the value could be retrieved, false otherwise
+     */
+    virtual bool asBool(bool &result) const = 0;
+
+    /**
+     * @brief   Return the double representation of the contained value.
+     *
+     * This function shall return a double value if the Adapter contains either
+     * an actual double, an integer, or a string that contains a valid
+     * representation of a numeric value (according to the C++ Std Library).
+     *
+     * An exception shall be thrown if the value cannot be cast to a double.
+     *
+     * @returns  Double representation of contained value.
+     */
+    virtual double asDouble() const = 0;
+
+    /**
+     * @brief   Retrieve the double representation of the contained value.
+     *
+     * This function shall retrieve a double value if the Adapter contains either
+     * an actual double, an integer, or a string that contains a valid
+     * representation of a numeric value (according to the C++ Std Library).
+     *
+     * The retrieved value is returned via reference.
+     *
+     * @param   result  reference to a double to set with retrieved value.
+     *
+     * @returns true if the value could be retrieved, false otherwise
+     */
+    virtual bool asDouble(double &result) const = 0;
+
+    /**
+     * @brief   Return the int64_t representation of the contained value.
+     *
+     * This function shall return an int64_t value if the Adapter contains either
+     * an actual integer, or a string that contains a valid representation of an
+     * integer value (according to the C++ Std Library).
+     *
+     * An exception shall be thrown if the value cannot be cast to an int64_t.
+     *
+     * @returns  int64_t representation of contained value.
+     */
+    virtual int64_t asInteger() const = 0;
+
+    /**
+     * @brief   Retrieve the int64_t representation of the contained value.
+     *
+     * This function shall retrieve an int64_t value if the Adapter contains
+     * either an actual integer, or a string that contains a valid
+     * representation of an integer value (according to the C++ Std Library).
+     *
+     * The retrieved value is returned via reference.
+     *
+     * @param   result  reference to a int64_t to set with retrieved value.
+     *
+     * @returns true if the value could be retrieved, false otherwise
+     */
+    virtual bool asInteger(int64_t &result) const = 0;
+
+    /**
+     * @brief   Return the string representation of the contained value.
+     *
+     * This function shall return a string value if the Adapter contains either
+     * an actual string, a literal value of another POD type, an empty array,
+     * an empty object, or null.
+     *
+     * An exception shall be thrown if the value cannot be cast to a string.
+     *
+     * @returns  string representation of contained value.
+     */
+    virtual std::string asString() const = 0;
+
+    /**
+     * @brief   Retrieve the string representation of the contained value.
+     *
+     * This function shall retrieve a string value if the Adapter contains either
+     * an actual string, a literal value of another POD type, an empty array,
+     * an empty object, or null.
+     *
+     * The retrieved value is returned via reference.
+     *
+     * @param   result  reference to a string to set with retrieved value.
+     *
+     * @returns true if the value could be retrieved, false otherwise
+     */
+    virtual bool asString(std::string &result) const = 0;
+
+    /**
+     * @brief   Compare the value held by this Adapter instance with the value
+     *          held by another Adapter instance.
+     *
+     * @param   other   the other adapter instance
+     * @param   strict  flag to use strict type comparison
+     *
+     * @returns true if values are equal, false otherwise
+     */
+    virtual bool equalTo(const Adapter &other, bool strict) const = 0;
+
+    /**
+     * @brief   Create a new FrozenValue instance that is equivalent to the
+     *          value contained by the Adapter.
+     *
+     * @returns pointer to a new FrozenValue instance, belonging to the caller.
+     */
+    virtual FrozenValue* freeze() const = 0;
+
+    /**
+     * @brief   Return the number of elements in the array.
+     *
+     * Throws an exception if the value is not an array.
+     *
+     * @return  number of elements if value is an array
+     */
+    virtual size_t getArraySize() const = 0;
+
+    /**
+     * @brief   Retrieve the number of elements in the array.
+     *
+     * This function shall return true or false to indicate whether or not the
+     * result value was set. If the contained value is not an array, the
+     * result value shall not be set. This applies even if the value could be
+     * cast to an empty array. The calling code is expected to handles those
+     * cases manually.
+     *
+     * @param   result  reference to size_t variable to set with result.
+     *
+     * @return  true if value retrieved successfully, false otherwise.
+     */
+    virtual bool getArraySize(size_t &result) const = 0;
+
+    /**
+     * @brief   Return the contained boolean value.
+     *
+     * This function shall throw an exception if the contained value is not a
+     * boolean.
+     *
+     * @returns contained boolean value.
+     */
+    virtual bool getBool() const = 0;
+
+    /**
+     * @brief   Retrieve the contained boolean value.
+     *
+     * This function shall retrieve the boolean value contained by this Adapter,
+     * and store it in the result variable that was passed by reference.
+     *
+     * @param   result  reference to boolean variable to set with result.
+     *
+     * @returns true if the value was retrieved, false otherwise.
+     */
+    virtual bool getBool(bool &result) const = 0;
+
+    /**
+     * @brief   Return the contained double value.
+     *
+     * This function shall throw an exception if the contained value is not a
+     * double.
+     *
+     * @returns contained double value.
+     */
+    virtual double getDouble() const = 0;
+
+    /**
+     * @brief   Retrieve the contained double value.
+     *
+     * This function shall retrieve the double value contained by this Adapter,
+     * and store it in the result variable that was passed by reference.
+     *
+     * @param   result  reference to double variable to set with result.
+     *
+     * @returns true if the value was retrieved, false otherwise.
+     */
+    virtual bool getDouble(double &result) const = 0;
+
+    /**
+     * @brief   Return the contained integer value.
+     *
+     * This function shall throw an exception if the contained value is not a
+     * integer.
+     *
+     * @returns contained integer value.
+     */
+    virtual int64_t getInteger() const = 0;
+
+    /**
+     * @brief   Retrieve the contained integer value.
+     *
+     * This function shall retrieve the integer value contained by this Adapter,
+     * and store it in the result variable that was passed by reference.
+     *
+     * @param   result  reference to integer variable to set with result.
+     *
+     * @returns true if the value was retrieved, false otherwise.
+     */
+    virtual bool getInteger(int64_t &result) const = 0;
+
+    /**
+     * @brief   Return the contained numeric value as a double.
+     *
+     * This function shall throw an exception if the contained value is not a
+     * integer or a double.
+     *
+     * @returns contained double or integral value.
+     */
+    virtual double getNumber() const = 0;
+
+    /**
+     * @brief   Retrieve the contained numeric value as a double.
+     *
+     * This function shall retrieve the double or integral value contained by
+     * this Adapter, and store it in the result variable that was passed by
+     * reference.
+     *
+     * @param   result  reference to double variable to set with result.
+     *
+     * @returns true if the value was retrieved, false otherwise.
+     */
+    virtual bool getNumber(double &result) const = 0;
+
+    /**
+     * @brief   Return the number of members in the object.
+     *
+     * Throws an exception if the value is not an object.
+     *
+     * @return  number of members if value is an object
+     */
+    virtual size_t getObjectSize() const = 0;
+
+    /**
+     * @brief   Retrieve the number of members in the object.
+     *
+     * This function shall return true or false to indicate whether or not the
+     * result value was set. If the contained value is not an object, the
+     * result value shall not be set. This applies even if the value could be
+     * cast to an empty object. The calling code is expected to handles those
+     * cases manually.
+     *
+     * @param   result  reference to size_t variable to set with result.
+     *
+     * @return  true if value retrieved successfully, false otherwise.
+     */
+    virtual bool getObjectSize(size_t &result) const = 0;
+
+    /**
+     * @brief   Return the contained string value.
+     *
+     * This function shall throw an exception if the contained value is not a
+     * string - even if the value could be cast to a string. The asString()
+     * function should be used when casting is allowed.
+     *
+     * @returns string contained by this Adapter
+     */
+    virtual std::string getString() const = 0;
+
+    /**
+     * @brief   Retrieve the contained string value.
+     *
+     * This function shall retrieve the string value contained by this Adapter,
+     * and store it in result variable that is passed by reference.
+     *
+     * @param   result  reference to string to set with result
+     *
+     * @returns true if string was retrieved, false otherwise
+     */
+    virtual bool getString(std::string &result) const = 0;
+
+    /**
+     * @brief   Returns whether or not this Adapter supports strict types.
+     *
+     * This function shall return true if the Adapter implementation supports
+     * strict types, or false if the Adapter fails to store any part of the
+     * type information supported by the Adapter interface.
+     *
+     * For example, the PropertyTreeAdapter implementation stores POD values as
+     * strings, effectively discarding any other type information. If you were
+     * to call isDouble() on a double stored by this Adapter, the result would
+     * be false. The maybeDouble(), asDouble() and various related functions
+     * are provided to perform type checking based on value rather than on type.
+     *
+     * The BasicAdapter template class provides implementations for the type-
+     * casting functions so that Adapter implementations are semantically
+     * equivalent in their type-casting behaviour.
+     *
+     * @returns true if Adapter supports strict types, false otherwise
+     */
+    virtual bool hasStrictTypes() const = 0;
+
+    /// Returns true if the contained value is definitely an array.
+    virtual bool isArray() const = 0;
+
+    /// Returns true if the contained value is definitely a boolean.
+    virtual bool isBool() const = 0;
+
+    /// Returns true if the contained value is definitely a double.
+    virtual bool isDouble() const = 0;
+
+    /// Returns true if the contained value is definitely an integer.
+    virtual bool isInteger() const = 0;
+
+    /// Returns true if the contained value is definitely a null.
+    virtual bool isNull() const = 0;
+
+    /// Returns true if the contained value is either a double or an integer.
+    virtual bool isNumber() const = 0;
+
+    /// Returns true if the contained value is definitely an object.
+    virtual bool isObject() const = 0;
+
+    /// Returns true if the contained value is definitely a string.
+    virtual bool isString() const = 0;
+
+    /**
+     * @brief   Returns true if the contained value can be cast to an array.
+     *
+     * @returns true if the contained value is an array, an empty string, or an
+     *          empty object.
+     */
+    virtual bool maybeArray() const = 0;
+
+    /**
+     * @brief   Returns true if the contained value can be cast to a boolean.
+     *
+     * @returns true if the contained value is a boolean, or one of the strings
+     *          'true' or 'false'. Note that numeric values are not to be cast
+     *          to boolean values.
+     */
+    virtual bool maybeBool() const = 0;
+
+    /**
+     * @brief   Returns true if the contained value can be cast to a double.
+     *
+     * @returns true if the contained value is a double, an integer, or a string
+     *          containing a double or integral value.
+     */
+    virtual bool maybeDouble() const = 0;
+
+    /**
+     * @brief   Returns true if the contained value can be cast to an integer.
+     *
+     * @returns true if the contained value is an integer, or a string
+     *          containing an integral value.
+     */
+    virtual bool maybeInteger() const = 0;
+
+    /**
+     * @brief   Returns true if the contained value can be cast to a null.
+     *
+     * @returns true if the contained value is null or an empty string.
+     */
+    virtual bool maybeNull() const = 0;
+
+    /**
+     * @brief   Returns true if the contained value can be cast to an object.
+     *
+     * @returns true if the contained value is an object, an empty array or
+     *          an empty string.
+     */
+    virtual bool maybeObject() const = 0;
+
+    /**
+     * @brief   Returns true if the contained value can be cast to a string.
+     *
+     * @returns true if the contained value is a non-null POD type, an empty
+     *          array, or an empty object.
+     */
+    virtual bool maybeString() const = 0;
+};
+
+/**
+ * @brief  Template struct that should be specialised for each concrete Adapter
+ *         class.
+ *
+ * @deprecated  This is a bit of a hack, and I'd like to remove it.
+ */
+template<typename T>
+struct AdapterTraits
+{
+
+};
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/basic_adapter.hpp b/subprojects/valijson/include/valijson/adapters/basic_adapter.hpp
new file mode 100644
index 000000000..84b2abdd1
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/basic_adapter.hpp
@@ -0,0 +1,859 @@
+#pragma once
+
+#include <cstdint>
+#include <sstream>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/internal/optional.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+/**
+ * @brief  A helper for the array and object member iterators.
+ *
+ * See http://www.stlsoft.org/doc-1.9/group__group____pattern____dereference__proxy.html
+ * for motivation
+ *
+ * @tparam Value  Name of the value type
+ */
+template<class Value>
+struct DerefProxy
+{
+    explicit DerefProxy(const Value& x)
+      : m_ref(x) { }
+
+    Value* operator->()
+    {
+        return std::addressof(m_ref);
+    }
+
+    explicit operator Value*()
+    {
+        return std::addressof(m_ref);
+    }
+
+private:
+    Value m_ref;
+};
+
+/**
+ * @brief  Template class that implements the expected semantics of an Adapter.
+ *
+ * Implementing all of the type-casting functionality for each Adapter is error
+ * prone and tedious, so this template class aims to minimise the duplication
+ * of code between various Adapter implementations. This template doesn't quite
+ * succeed in removing all duplication, but it has greatly simplified the
+ * implementation of a new Adapter by encapsulating the type-casting semantics
+ * and a lot of the trivial functionality associated with the Adapter interface.
+ *
+ * By inheriting from this template class, Adapter implementations will inherit
+ * the exception throwing behaviour that is expected by other parts of the
+ * Valijson library.
+ *
+ * @tparam  AdapterType       Self-referential name of the Adapter being
+ *                            specialised.
+ * @tparam  ArrayType         Name of the type that will be returned by the
+ *                            getArray() function. Instances of this type should
+ *                            provide begin(), end() and size() functions so
+ *                            that it is possible to iterate over the values in
+ *                            the array.
+ * @tparam  ObjectMemberType  Name of the type exposed when iterating over the
+ *                            contents of an object returned by getObject().
+ * @tparam  ObjectType        Name of the type that will be returned by the
+ *                            getObject() function. Instances of this type
+ *                            should provide begin(), end(), find() and size()
+ *                            functions so that it is possible to iterate over
+ *                            the members of the object.
+ * @tparam  ValueType         Name of the type that provides a consistent
+ *                            interface to a JSON value for a parser. For
+ *                            example, this type should provide the getDouble()
+ *                            and isDouble() functions. But it does not need to
+ *                            know how to cast values from one type to another -
+ *                            that functionality is provided by this template
+ *                            class.
+ */
+template<
+    typename AdapterType,
+    typename ArrayType,
+    typename ObjectMemberType,
+    typename ObjectType,
+    typename ValueType>
+class BasicAdapter: public Adapter
+{
+protected:
+
+    /**
+     * @brief   Functor for comparing two arrays.
+     *
+     * This functor is used to compare the elements in an array of the type
+     * ArrayType with individual values provided as generic Adapter objects.
+     * Comparison is performed by the () operator.
+     *
+     * The functor works by maintaining an iterator for the current position
+     * in an array. Each time the () operator is called, the value at this
+     * position is compared with the value passed as an argument to ().
+     * Immediately after the comparison, the iterator will be incremented.
+     *
+     * This functor is designed to be passed to the applyToArray() function
+     * of an Adapter object.
+     */
+    class ArrayComparisonFunctor
+    {
+    public:
+
+        /**
+         * @brief   Construct an ArrayComparisonFunctor for an array.
+         *
+         * @param   array   Array to compare values against
+         * @param   strict  Flag to use strict type comparison
+         */
+        ArrayComparisonFunctor(const ArrayType &array, bool strict)
+          : m_itr(array.begin()),
+            m_end(array.end()),
+            m_strict(strict) { }
+
+        /**
+         * @brief   Compare a value against the current element in the array.
+         *
+         * @param   adapter  Value to be compared with current element
+         *
+         * @returns true if values are equal, false otherwise.
+         */
+        bool operator()(const Adapter &adapter)
+        {
+            if (m_itr == m_end) {
+                return false;
+            }
+
+            return AdapterType(*m_itr++).equalTo(adapter, m_strict);
+        }
+
+    private:
+
+        /// Iterator for current element in the array
+        typename ArrayType::const_iterator m_itr;
+
+        /// Iterator for one-past the last element of the array
+        typename ArrayType::const_iterator m_end;
+
+        /// Flag to use strict type comparison
+        const bool m_strict;
+    };
+
+    /**
+     * @brief   Functor for comparing two objects
+     *
+     * This functor is used to compare the members of an object of the type
+     * ObjectType with key-value pairs belonging to another object.
+     *
+     * The functor works by maintaining a reference to an object provided via
+     * the constructor. When time the () operator is called with a key-value
+     * pair as arguments, the function will attempt to find the key in the
+     * base object. If found, the associated value will be compared with the
+     * value provided to the () operator.
+     *
+     * This functor is designed to be passed to the applyToObject() function
+     * of an Adapter object.
+     */
+    class ObjectComparisonFunctor
+    {
+    public:
+
+        /**
+         * @brief   Construct a new ObjectComparisonFunctor for an object.
+         *
+         * @param   object  object to use as comparison baseline
+         * @param   strict  flag to use strict type-checking
+         */
+        ObjectComparisonFunctor(const ObjectType &object, bool strict)
+          : m_object(object),
+            m_strict(strict) { }
+
+        /**
+         * @brief   Find a key in the object and compare its value.
+         *
+         * @param   key    Key to find
+         * @param   value  Value to be compared against
+         *
+         * @returns true if key is found and values are equal, false otherwise.
+         */
+        bool operator()(const std::string &key, const Adapter &value)
+        {
+            const typename ObjectType::const_iterator itr = m_object.find(key);
+            if (itr == m_object.end()) {
+                return false;
+            }
+
+            return (*itr).second.equalTo(value, m_strict);
+        }
+
+    private:
+
+        /// Object to be used as a comparison baseline
+        const ObjectType &m_object;
+
+        /// Flag to use strict type-checking
+        bool m_strict;
+    };
+
+
+public:
+
+    /// Alias for ArrayType template parameter
+    typedef ArrayType Array;
+
+    /// Alias for ObjectMemberType template parameter
+    typedef ObjectMemberType ObjectMember;
+
+    /// Alias for ObjectType template parameter
+    typedef ObjectType Object;
+
+    /**
+     * @brief   Construct an Adapter using the default value.
+     *
+     * This constructor relies on the default constructor of the ValueType
+     * class provided as a template argument.
+     */
+    BasicAdapter() = default;
+
+    /**
+     * @brief   Construct an Adapter using a specified ValueType object.
+     *
+     * This constructor relies on the copy constructor of the ValueType
+     * class provided as template argument.
+     */
+    explicit BasicAdapter(const ValueType &value)
+      : m_value(value) { }
+
+    bool applyToArray(ArrayValueCallback fn) const override
+    {
+        if (!maybeArray()) {
+            return false;
+        }
+
+        // Due to the fact that the only way a value can be 'maybe an array' is
+        // if it is an empty string or empty object, we only need to go to
+        // effort of constructing an ArrayType instance if the value is
+        // definitely an array.
+        if (m_value.isArray()) {
+            const opt::optional<Array> array = m_value.getArrayOptional();
+            for (const AdapterType element : *array) {
+                if (!fn(element)) {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    bool applyToObject(ObjectMemberCallback fn) const override
+    {
+        if (!maybeObject()) {
+            return false;
+        }
+
+        if (m_value.isObject()) {
+            const opt::optional<Object> object = m_value.getObjectOptional();
+            for (const ObjectMemberType member : *object) {
+                if (!fn(member.first, AdapterType(member.second))) {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Return an ArrayType instance containing an array representation
+     *          of the value held by this Adapter.
+     *
+     * This is a convenience function that is not actually declared in the
+     * Adapter interface, but allows for useful techniques such as procedural
+     * iteration over the elements in an array. The ArrayType instance that is
+     * returned by this function is compatible with the BOOST_FOREACH macro.
+     *
+     * If the contained value is either an empty object, or an empty string,
+     * then this function will cast the value to an empty array.
+     *
+     * @returns ArrayType instance containing an array representation of the
+     *          value held by this Adapter.
+     */
+    ArrayType asArray() const
+    {
+        if (m_value.isArray()) {
+            return *m_value.getArrayOptional();
+        } else if (m_value.isObject()) {
+            size_t objectSize;
+            if (m_value.getObjectSize(objectSize) && objectSize == 0) {
+                return ArrayType();
+            }
+        } else if (m_value.isString()) {
+            std::string stringValue;
+            if (m_value.getString(stringValue) && stringValue.empty()) {
+                return ArrayType();
+            }
+        }
+
+        throwRuntimeError("JSON value cannot be cast to an array.");
+    }
+
+    bool asBool() const override
+    {
+        bool result;
+        if (asBool(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value cannot be cast to a boolean.");
+    }
+
+    bool asBool(bool &result) const override
+    {
+        if (m_value.isBool()) {
+            return m_value.getBool(result);
+        } else if (m_value.isString()) {
+            std::string s;
+            if (m_value.getString(s)) {
+                if (s == "true") {
+                    result = true;
+                    return true;
+                } else if (s == "false") {
+                    result = false;
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    double asDouble() const override
+    {
+        double result;
+        if (asDouble(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value cannot be cast to a double.");
+    }
+
+    bool asDouble(double &result) const override
+    {
+        if (m_value.isDouble()) {
+            return m_value.getDouble(result);
+        } else if (m_value.isInteger()) {
+            int64_t i;
+            if (m_value.getInteger(i)) {
+                result = double(i);
+                return true;
+            }
+        } else if (m_value.isString()) {
+            std::string s;
+            if (m_value.getString(s)) {
+                const char *b = s.c_str();
+                char *e = nullptr;
+                double x = strtod(b, &e);
+                if (e == b || e != b + s.length()) {
+                    return false;
+                }
+                result = x;
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    int64_t asInteger() const override
+    {
+        int64_t result;
+        if (asInteger(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value cannot be cast as an integer.");
+    }
+
+    bool asInteger(int64_t &result) const override
+    {
+        if (m_value.isInteger()) {
+            return m_value.getInteger(result);
+        } else if (m_value.isString()) {
+            std::string s;
+            if (m_value.getString(s)) {
+                std::istringstream i(s);
+                int64_t x;
+                char c;
+                if (!(!(i >> x) || i.get(c))) {
+                    result = x;
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Return an ObjectType instance containing an array representation
+     *          of the value held by this Adapter.
+     *
+     * This is a convenience function that is not actually declared in the
+     * Adapter interface, but allows for useful techniques such as procedural
+     * iteration over the members of the object. The ObjectType instance that is
+     * returned by this function is compatible with the BOOST_FOREACH macro.
+     *
+     * @returns ObjectType instance containing an object representation of the
+     *          value held by this Adapter.
+     */
+    ObjectType asObject() const
+    {
+        if (m_value.isObject()) {
+            return *m_value.getObjectOptional();
+        } else if (m_value.isArray()) {
+            size_t arraySize;
+            if (m_value.getArraySize(arraySize) && arraySize == 0) {
+                return ObjectType();
+            }
+        } else if (m_value.isString()) {
+            std::string stringValue;
+            if (m_value.getString(stringValue) && stringValue.empty()) {
+                return ObjectType();
+            }
+        }
+
+        throwRuntimeError("JSON value cannot be cast to an object.");
+    }
+
+    std::string asString() const override
+    {
+        std::string result;
+        if (asString(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value cannot be cast to a string.");
+    }
+
+    bool asString(std::string &result) const override
+    {
+        if (m_value.isString()) {
+            return m_value.getString(result);
+        } else if (m_value.isNull()) {
+            result.clear();
+            return true;
+        } else if (m_value.isArray()) {
+            size_t arraySize;
+            if (m_value.getArraySize(arraySize) && arraySize == 0) {
+                result.clear();
+                return true;
+            }
+        } else if (m_value.isObject()) {
+            size_t objectSize;
+            if (m_value.getObjectSize(objectSize) && objectSize == 0) {
+                result.clear();
+                return true;
+            }
+        } else if (m_value.isBool()) {
+            bool boolValue;
+            if (m_value.getBool(boolValue)) {
+                result = boolValue ? "true" : "false";
+                return true;
+            }
+        } else if (m_value.isInteger()) {
+            int64_t integerValue;
+            if (m_value.getInteger(integerValue)) {
+                result = std::to_string(integerValue);
+                return true;
+            }
+        } else if (m_value.isDouble()) {
+            double doubleValue;
+            if (m_value.getDouble(doubleValue)) {
+                result = std::to_string(doubleValue);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override
+    {
+        if (isNull() || (!strict && maybeNull())) {
+            return other.isNull() || (!strict && other.maybeNull());
+        } else if (isBool() || (!strict && maybeBool())) {
+            return (other.isBool() || (!strict && other.maybeBool())) && other.asBool() == asBool();
+        } else if (isNumber() && strict) {
+            return other.isNumber() && other.getNumber() == getNumber();
+        } else if (!strict && maybeDouble()) {
+            return (other.maybeDouble() && other.asDouble() == asDouble());
+        } else if (!strict && maybeInteger()) {
+            return (other.maybeInteger() && other.asInteger() == asInteger());
+        } else if (isString() || (!strict && maybeString())) {
+            return (other.isString() || (!strict && other.maybeString())) &&
+                other.asString() == asString();
+        } else if (isArray()) {
+            if (other.isArray() && getArraySize() == other.getArraySize()) {
+                const opt::optional<ArrayType> array = m_value.getArrayOptional();
+                if (array) {
+                    ArrayComparisonFunctor fn(*array, strict);
+                    return other.applyToArray(fn);
+                }
+            } else if (!strict && other.maybeArray() && getArraySize() == 0) {
+                return true;
+            }
+        } else if (isObject()) {
+            if (other.isObject() && other.getObjectSize() == getObjectSize()) {
+                const opt::optional<ObjectType> object = m_value.getObjectOptional();
+                if (object) {
+                    ObjectComparisonFunctor fn(*object, strict);
+                    return other.applyToObject(fn);
+                }
+            } else if (!strict && other.maybeObject() && getObjectSize() == 0) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Return an ArrayType instance representing the array contained
+     *          by this Adapter instance.
+     *
+     * This is a convenience function that is not actually declared in the
+     * Adapter interface, but allows for useful techniques such as procedural
+     * iteration over the elements in an array. The ArrayType instance that is
+     * returned by this function is compatible with the BOOST_FOREACH macro.
+     *
+     * If the contained is not an array, this function will throw an exception.
+     *
+     * @returns ArrayType instance containing an array representation of the
+     *          value held by this Adapter.
+     */
+    ArrayType getArray() const
+    {
+        opt::optional<ArrayType> arrayValue = m_value.getArrayOptional();
+        if (arrayValue) {
+            return *arrayValue;
+        }
+
+        throwRuntimeError("JSON value is not an array.");
+    }
+
+    size_t getArraySize() const override
+    {
+        size_t result;
+        if (m_value.getArraySize(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value is not an array.");
+    }
+
+    bool getArraySize(size_t &result) const override
+    {
+        return m_value.getArraySize(result);
+    }
+
+    bool getBool() const override
+    {
+        bool result;
+        if (getBool(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value is not a boolean.");
+    }
+
+    bool getBool(bool &result) const override
+    {
+        return m_value.getBool(result);
+    }
+
+    double getDouble() const override
+    {
+        double result;
+        if (getDouble(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value is not a double.");
+    }
+
+    bool getDouble(double &result) const override
+    {
+        return m_value.getDouble(result);
+    }
+
+    int64_t getInteger() const override
+    {
+        int64_t result;
+        if (getInteger(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value is not an integer.");
+    }
+
+    bool getInteger(int64_t &result) const override
+    {
+        return m_value.getInteger(result);
+    }
+
+    double getNumber() const override
+    {
+        double result;
+        if (getNumber(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value is not a number.");
+    }
+
+    bool getNumber(double &result) const override
+    {
+        if (isDouble()) {
+            return getDouble(result);
+        } else if (isInteger()) {
+            int64_t integerResult;
+            if (getInteger(integerResult)) {
+                result = static_cast<double>(integerResult);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Return an ObjectType instance representing the object contained
+     *          by this Adapter instance.
+     *
+     * This is a convenience function that is not actually declared in the
+     * Adapter interface, but allows for useful techniques such as procedural
+     * iteration over the members of an object. The ObjectType instance that is
+     * returned by this function is compatible with the BOOST_FOREACH macro.
+     *
+     * If the contained is not an object, this function will throw an exception.
+     *
+     * @returns ObjectType instance containing an array representation of the
+     *          value held by this Adapter.
+     */
+    ObjectType getObject() const
+    {
+        opt::optional<ObjectType> objectValue = m_value.getObjectOptional();
+        if (objectValue) {
+            return *objectValue;
+        }
+
+        throwRuntimeError("JSON value is not an object.");
+    }
+
+    size_t getObjectSize() const override
+    {
+        size_t result;
+        if (getObjectSize(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value is not an object.");
+    }
+
+    bool getObjectSize(size_t &result) const override
+    {
+        return m_value.getObjectSize(result);
+    }
+
+    std::string getString() const override
+    {
+        std::string result;
+        if (getString(result)) {
+            return result;
+        }
+
+        throwRuntimeError("JSON value is not a string.");
+    }
+
+    bool getString(std::string &result) const override
+    {
+        return m_value.getString(result);
+    }
+
+    FrozenValue * freeze() const override
+    {
+        return m_value.freeze();
+    }
+
+    bool hasStrictTypes() const override
+    {
+        return ValueType::hasStrictTypes();
+    }
+
+    bool isArray() const override
+    {
+        return m_value.isArray();
+    }
+
+    bool isBool() const override
+    {
+        return m_value.isBool();
+    }
+
+    bool isDouble() const override
+    {
+        return m_value.isDouble();
+    }
+
+    bool isInteger() const override
+    {
+        return m_value.isInteger();
+    }
+
+    bool isNull() const override
+    {
+        return m_value.isNull();
+    }
+
+    bool isNumber() const override
+    {
+        return m_value.isInteger() || m_value.isDouble();
+    }
+
+    bool isObject() const override
+    {
+        return m_value.isObject();
+    }
+
+    bool isString() const override
+    {
+        return m_value.isString();
+    }
+
+    bool maybeArray() const override
+    {
+        if (m_value.isArray()) {
+            return true;
+        } else if (m_value.isObject()) {
+            size_t objectSize;
+            if (m_value.getObjectSize(objectSize) && objectSize == 0) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    bool maybeBool() const override
+    {
+        if (m_value.isBool()) {
+            return true;
+        } else if (maybeString()) {
+            std::string stringValue;
+            if (m_value.getString(stringValue)) {
+                if (stringValue == "true" || stringValue == "false") {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    bool maybeDouble() const override
+    {
+        if (m_value.isNumber()) {
+            return true;
+        } else if (maybeString()) {
+            std::string s;
+            if (m_value.getString(s)) {
+                const char *b = s.c_str();
+                char *e = nullptr;
+                strtod(b, &e);
+                return e != b && e == b + s.length();
+            }
+        }
+
+        return false;
+    }
+
+    bool maybeInteger() const override
+    {
+        if (m_value.isInteger()) {
+            return true;
+        } else if (maybeString()) {
+            std::string s;
+            if (m_value.getString(s)) {
+                std::istringstream i(s);
+                int64_t x;
+                char c;
+                if (!(i >> x) || i.get(c)) {
+                    return false;
+                }
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    bool maybeNull() const override
+    {
+        if (m_value.isNull()) {
+            return true;
+        } else if (maybeString()) {
+            std::string stringValue;
+            if (m_value.getString(stringValue)) {
+                if (stringValue.empty()) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    bool maybeObject() const override
+    {
+        if (m_value.isObject()) {
+            return true;
+        } else if (maybeArray()) {
+            size_t arraySize;
+            if (m_value.getArraySize(arraySize) && arraySize == 0) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    bool maybeString() const override
+    {
+        if (m_value.isString() || m_value.isBool() || m_value.isInteger() || m_value.isDouble()) {
+            return true;
+        } else if (m_value.isObject()) {
+            size_t objectSize;
+            if (m_value.getObjectSize(objectSize) && objectSize == 0) {
+                return true;
+            }
+        } else if (m_value.isArray()) {
+            size_t arraySize;
+            if (m_value.getArraySize(arraySize) && arraySize == 0) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+private:
+
+    const ValueType m_value;
+};
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/frozen_value.hpp b/subprojects/valijson/include/valijson/adapters/frozen_value.hpp
new file mode 100644
index 000000000..56b5eafc5
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/frozen_value.hpp
@@ -0,0 +1,52 @@
+#pragma once
+
+#include <valijson/adapters/adapter.hpp>
+
+namespace valijson {
+namespace adapters {
+
+/**
+ * @brief   An interface that provides minimal access to a stored JSON value.
+ *
+ * The main reason that this interface exists is to support the 'enum'
+ * constraint. Each Adapter type is expected to provide an implementation of
+ * this interface. That class should be able to maintain its own copy of a
+ * JSON value, independent of the original document.
+ *
+ * This interface currently provides just the clone and equalTo functions, but
+ * could be expanded to include other functions declared in the Adapter
+ * interface.
+ *
+ * @todo  it would be nice to better integrate this with the Adapter interface
+ */
+class FrozenValue
+{
+public:
+
+    /**
+     * @brief   Virtual destructor defined to ensure deletion via base-class
+     *          pointers is safe.
+     */
+    virtual ~FrozenValue() { }
+
+    /**
+     * @brief   Clone the stored value and return a pointer to a new FrozenValue
+     *          object containing the value.
+     */
+    virtual FrozenValue *clone() const = 0;
+
+    /**
+     * @brief   Return true if the stored value is equal to the value contained
+     *          by an Adapter instance.
+     *
+     * @param   adapter  Adapter to compare value against
+     * @param   strict   Flag to use strict type comparison
+     *
+     * @returns true if values are equal, false otherwise
+     */
+    virtual bool equalTo(const Adapter &adapter, bool strict) const = 0;
+
+};
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/json11_adapter.hpp b/subprojects/valijson/include/valijson/adapters/json11_adapter.hpp
new file mode 100644
index 000000000..41749b2fc
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/json11_adapter.hpp
@@ -0,0 +1,711 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation for the json11 parser library.
+ *
+ * Include this file in your program to enable support for json11.
+ *
+ * This file defines the following classes (not in this order):
+ *  - Json11Adapter
+ *  - Json11Array
+ *  - Json11ArrayValueIterator
+ *  - Json11FrozenValue
+ *  - Json11Object
+ *  - Json11ObjectMember
+ *  - Json11ObjectMemberIterator
+ *  - Json11Value
+ *
+ * Due to the dependencies that exist between these classes, the ordering of
+ * class declarations and definitions may be a bit confusing. The best place to
+ * start is Json11Adapter. This class definition is actually very small,
+ * since most of the functionality is inherited from the BasicAdapter class.
+ * Most of the classes in this file are provided as template arguments to the
+ * inherited BasicAdapter class.
+ */
+
+#pragma once
+
+#include <string>
+#include <json11.hpp>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+class Json11Adapter;
+class Json11ArrayValueIterator;
+class Json11ObjectMemberIterator;
+
+typedef std::pair<std::string, Json11Adapter> Json11ObjectMember;
+
+/**
+ * @brief  Light weight wrapper for a Json11 array value.
+ *
+ * This class is light weight wrapper for a Json11 array. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * Json11 value, assumed to be an array, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class Json11Array
+{
+public:
+
+    typedef Json11ArrayValueIterator const_iterator;
+    typedef Json11ArrayValueIterator iterator;
+
+    /// Construct a Json11Array referencing an empty array.
+    Json11Array()
+      : m_value(emptyArray()) { }
+
+    /**
+     * @brief   Construct a Json11Array referencing a specific Json11
+     *          value.
+     *
+     * @param   value   reference to a Json11 value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an array.
+     */
+    Json11Array(const json11::Json &value)
+      : m_value(value)
+    {
+        if (!value.is_array()) {
+            throwRuntimeError("Value is not an array.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for the first element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying Json11 implementation.
+     */
+    Json11ArrayValueIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for one-past the last element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying Json11 implementation.
+     */
+    Json11ArrayValueIterator end() const;
+
+    /// Return the number of elements in the array
+    size_t size() const
+    {
+        return m_value.array_items().size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a Json11 value that is an empty array.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const json11::Json & emptyArray()
+    {
+        static const json11::Json array((json11::Json::array()));
+        return array;
+    }
+
+    /// Reference to the contained value
+    const json11::Json &m_value;
+};
+
+/**
+ * @brief  Light weight wrapper for a Json11 object.
+ *
+ * This class is light weight wrapper for a Json11 object. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * Json11 value, assumed to be an object, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class Json11Object
+{
+public:
+
+    typedef Json11ObjectMemberIterator const_iterator;
+    typedef Json11ObjectMemberIterator iterator;
+
+    /// Construct a Json11Object referencing an empty object singleton.
+    Json11Object()
+      : m_value(emptyObject()) { }
+
+    /**
+     * @brief   Construct a Json11Object referencing a specific Json11
+     *          value.
+     *
+     * @param   value  reference to a Json11 value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an object.
+     */
+    Json11Object(const json11::Json &value)
+      : m_value(value)
+    {
+        if (!value.is_object()) {
+            throwRuntimeError("Value is not an object.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for this first object member
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying Json11 implementation.
+     */
+    Json11ObjectMemberIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for an invalid object member that indicates
+     *          the end of the collection.
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying Json11 implementation.
+     */
+    Json11ObjectMemberIterator end() const;
+
+    /**
+     * @brief   Return an iterator for the object member with the specified
+     *          property name.
+     *
+     * If an object member with the specified name does not exist, the iterator
+     * returned will be the same as the iterator returned by the end() function.
+     *
+     * @param   propertyName  property name to search for
+     */
+    Json11ObjectMemberIterator find(const std::string &propertyName) const;
+
+    /// Returns the number of members belonging to this object.
+    size_t size() const
+    {
+        return m_value.object_items().size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a Json11 value that is empty object.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const json11::Json & emptyObject()
+    {
+        static const json11::Json object((json11::Json::object()));
+        return object;
+    }
+
+    /// Reference to the contained object
+    const json11::Json &m_value;
+};
+
+/**
+ * @brief   Stores an independent copy of a Json11 value.
+ *
+ * This class allows a Json11 value to be stored independent of its original
+ * document. Json11 makes this easy to do, as it does not perform any
+ * custom memory management.
+ *
+ * @see FrozenValue
+ */
+class Json11FrozenValue: public FrozenValue
+{
+public:
+
+    /**
+     * @brief  Make a copy of a Json11 value
+     *
+     * @param  source  the Json11 value to be copied
+     */
+    explicit Json11FrozenValue(json11::Json source)
+      : m_value(std::move(source)) { }
+
+    FrozenValue * clone() const override
+    {
+        return new Json11FrozenValue(m_value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+
+    /// Stored Json11 value
+    json11::Json m_value;
+};
+
+/**
+ * @brief   Light weight wrapper for a Json11 value.
+ *
+ * This class is passed as an argument to the BasicAdapter template class,
+ * and is used to provide access to a Json11 value. This class is responsible
+ * for the mechanics of actually reading a Json11 value, whereas the
+ * BasicAdapter class is responsible for the semantics of type comparisons
+ * and conversions.
+ *
+ * The functions that need to be provided by this class are defined implicitly
+ * by the implementation of the BasicAdapter template class.
+ *
+ * @see BasicAdapter
+ */
+class Json11Value
+{
+public:
+
+    /// Construct a wrapper for the empty object singleton
+    Json11Value()
+      : m_value(emptyObject()) { }
+
+    /// Construct a wrapper for a specific Json11 value
+    Json11Value(const json11::Json &value)
+      : m_value(value) { }
+
+    /**
+     * @brief   Create a new Json11FrozenValue instance that contains the
+     *          value referenced by this Json11Value instance.
+     *
+     * @returns pointer to a new Json11FrozenValue instance, belonging to the
+     *          caller.
+     */
+    FrozenValue * freeze() const
+    {
+        return new Json11FrozenValue(m_value);
+    }
+
+    /**
+     * @brief   Optionally return a Json11Array instance.
+     *
+     * If the referenced Json11 value is an array, this function will return
+     * a std::optional containing a Json11Array instance referencing the
+     * array.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<Json11Array> getArrayOptional() const
+    {
+        if (m_value.is_array()) {
+            return opt::make_optional(Json11Array(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of elements in the array
+     *
+     * If the referenced Json11 value is an array, this function will
+     * retrieve the number of elements in the array and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of elements was retrieved, false otherwise.
+     */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_value.is_array()) {
+            result = m_value.array_items().size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getBool(bool &result) const
+    {
+        if (m_value.is_bool()) {
+            result = m_value.bool_value();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getDouble(double &result) const
+    {
+        if (m_value.is_number()) {
+            result = m_value.number_value();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getInteger(int64_t &result) const
+    {
+        if (isInteger()) {
+            result = m_value.int_value();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * @brief   Optionally return a Json11Object instance.
+     *
+     * If the referenced Json11 value is an object, this function will return a
+     * std::optional containing a Json11Object instance referencing the
+     * object.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<Json11Object> getObjectOptional() const
+    {
+        if (m_value.is_object()) {
+            return opt::make_optional(Json11Object(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of members in the object
+     *
+     * If the referenced Json11 value is an object, this function will
+     * retrieve the number of members in the object and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of members was retrieved, false otherwise.
+     */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_value.is_object()) {
+            result = m_value.object_items().size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value.is_string()) {
+            result = m_value.string_value();
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return true;
+    }
+
+    bool isArray() const
+    {
+        return m_value.is_array();
+    }
+
+    bool isBool() const
+    {
+        return m_value.is_bool();
+    }
+
+    bool isDouble() const
+    {
+        return m_value.is_number();
+    }
+
+    bool isInteger() const
+    {
+        return m_value.is_number() && m_value.int_value() == m_value.number_value();
+    }
+
+    bool isNull() const
+    {
+        return m_value.is_null();
+    }
+
+    bool isNumber() const
+    {
+        return m_value.is_number();
+    }
+
+    bool isObject() const
+    {
+        return m_value.is_object();
+    }
+
+    bool isString() const
+    {
+        return m_value.is_string();
+    }
+
+private:
+
+    /// Return a reference to an empty object singleton
+    static const json11::Json & emptyObject()
+    {
+        static const json11::Json object((json11::Json::object()));
+        return object;
+    }
+
+    /// Reference to the contained Json11 value.
+    const json11::Json &m_value;
+};
+
+/**
+ * @brief   An implementation of the Adapter interface supporting Json11.
+ *
+ * This class is defined in terms of the BasicAdapter template class, which
+ * helps to ensure that all of the Adapter implementations behave consistently.
+ *
+ * @see Adapter
+ * @see BasicAdapter
+ */
+class Json11Adapter:
+    public BasicAdapter<Json11Adapter,
+                        Json11Array,
+                        Json11ObjectMember,
+                        Json11Object,
+                        Json11Value>
+{
+public:
+
+    /// Construct a Json11Adapter that contains an empty object
+    Json11Adapter()
+      : BasicAdapter() { }
+
+    /// Construct a Json11Adapter containing a specific Json11 value
+    Json11Adapter(const json11::Json &value)
+      : BasicAdapter(value) { }
+};
+
+/**
+ * @brief   Class for iterating over values held in a JSON array.
+ *
+ * This class provides a JSON array iterator that dereferences as an instance of
+ * Json11Adapter representing a value stored in the array. It has been
+ * implemented using the boost iterator_facade template.
+ *
+ * @see Json11Array
+ */
+class Json11ArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = Json11Adapter;
+    using difference_type = Json11Adapter;
+    using pointer = Json11Adapter*;
+    using reference = Json11Adapter&;
+
+    /**
+     * @brief   Construct a new Json11ArrayValueIterator using an existing
+     *          Json11 iterator.
+     *
+     * @param   itr  Json11 iterator to store
+     */
+    Json11ArrayValueIterator(const json11::Json::array::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /// Returns a Json11Adapter that contains the value of the current
+    /// element.
+    Json11Adapter operator*() const
+    {
+        return Json11Adapter(*m_itr);
+    }
+
+    DerefProxy<Json11Adapter> operator->() const
+    {
+        return DerefProxy<Json11Adapter>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator against another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  iterator to compare against
+     *
+     * @returns true   if the iterators are equal, false otherwise.
+     */
+    bool operator==(const Json11ArrayValueIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const Json11ArrayValueIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const Json11ArrayValueIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    Json11ArrayValueIterator operator++(int)
+    {
+        Json11ArrayValueIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const Json11ArrayValueIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        m_itr += n;
+    }
+
+private:
+
+    json11::Json::array::const_iterator m_itr;
+};
+
+/**
+ * @brief   Class for iterating over the members belonging to a JSON object.
+ *
+ * This class provides a JSON object iterator that dereferences as an instance
+ * of Json11ObjectMember representing one of the members of the object. It
+ * has been implemented using the boost iterator_facade template.
+ *
+ * @see Json11Object
+ * @see Json11ObjectMember
+ */
+class Json11ObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = Json11ObjectMember;
+    using difference_type = Json11ObjectMember;
+    using pointer = Json11ObjectMember*;
+    using reference = Json11ObjectMember&;
+
+    /**
+     * @brief   Construct an iterator from a Json11 iterator.
+     *
+     * @param   itr  Json11 iterator to store
+     */
+    Json11ObjectMemberIterator(const json11::Json::object::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /**
+     * @brief   Returns a Json11ObjectMember that contains the key and value
+     *          belonging to the object member identified by the iterator.
+     */
+    Json11ObjectMember operator*() const
+    {
+        return Json11ObjectMember(m_itr->first, m_itr->second);
+    }
+
+    DerefProxy<Json11ObjectMember> operator->() const
+    {
+        return DerefProxy<Json11ObjectMember>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator with another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  Iterator to compare with
+     *
+     * @returns true if the underlying iterators are equal, false otherwise
+     */
+    bool operator==(const Json11ObjectMemberIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const Json11ObjectMemberIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const Json11ObjectMemberIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    Json11ObjectMemberIterator operator++(int)
+    {
+        Json11ObjectMemberIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const Json11ObjectMemberIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+private:
+
+    /// Iternal copy of the original Json11 iterator
+    json11::Json::object::const_iterator m_itr;
+};
+
+/// Specialisation of the AdapterTraits template struct for Json11Adapter.
+template<>
+struct AdapterTraits<valijson::adapters::Json11Adapter>
+{
+    typedef json11::Json DocumentType;
+
+    static std::string adapterName()
+    {
+        return "Json11Adapter";
+    }
+};
+
+inline bool Json11FrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return Json11Adapter(m_value).equalTo(other, strict);
+}
+
+inline Json11ArrayValueIterator Json11Array::begin() const
+{
+    return m_value.array_items().begin();
+}
+
+inline Json11ArrayValueIterator Json11Array::end() const
+{
+    return m_value.array_items().end();
+}
+
+inline Json11ObjectMemberIterator Json11Object::begin() const
+{
+    return m_value.object_items().begin();
+}
+
+inline Json11ObjectMemberIterator Json11Object::end() const
+{
+    return m_value.object_items().end();
+}
+
+inline Json11ObjectMemberIterator Json11Object::find(
+    const std::string &propertyName) const
+{
+    return m_value.object_items().find(propertyName);
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/jsoncpp_adapter.hpp b/subprojects/valijson/include/valijson/adapters/jsoncpp_adapter.hpp
new file mode 100644
index 000000000..2fd1fe74b
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/jsoncpp_adapter.hpp
@@ -0,0 +1,724 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation for the JsonCpp parser library.
+ *
+ * Include this file in your program to enable support for JsonCpp.
+ *
+ * This file defines the following classes (not in this order):
+ *  - JsonCppAdapter
+ *  - JsonCppArray
+ *  - JsonCppArrayValueIterator
+ *  - JsonCppFrozenValue
+ *  - JsonCppObject
+ *  - JsonCppObjectMember
+ *  - JsonCppObjectMemberIterator
+ *  - JsonCppValue
+ *
+ * Due to the dependencies that exist between these classes, the ordering of
+ * class declarations and definitions may be a bit confusing. The best place to
+ * start is JsonCppAdapter. This class definition is actually very small,
+ * since most of the functionality is inherited from the BasicAdapter class.
+ * Most of the classes in this file are provided as template arguments to the
+ * inherited BasicAdapter class.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <string>
+#include <iterator>
+
+#include <json/json.h>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+class JsonCppAdapter;
+class JsonCppArrayValueIterator;
+class JsonCppObjectMemberIterator;
+
+typedef std::pair<std::string, JsonCppAdapter> JsonCppObjectMember;
+
+/**
+ * @brief  Light weight wrapper for a JsonCpp array value.
+ *
+ * This class is light weight wrapper for a JsonCpp array. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * JsonCpp value, assumed to be an array, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class JsonCppArray
+{
+public:
+
+    typedef JsonCppArrayValueIterator const_iterator;
+    typedef JsonCppArrayValueIterator iterator;
+
+    /// Construct a JsonCppArray referencing an empty array.
+    JsonCppArray()
+      : m_value(emptyArray()) { }
+
+    /**
+     * @brief   Construct a JsonCppArray referencing a specific JsonCpp value.
+     *
+     * @param   value   reference to a JsonCpp value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an array.
+     */
+    JsonCppArray(const Json::Value &value)
+      : m_value(value)
+    {
+        if (!value.isArray()) {
+            throwRuntimeError("Value is not an array.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for the first element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying JsonCpp implementation.
+     */
+    JsonCppArrayValueIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for one-past the last element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying JsonCpp implementation.
+     */
+    JsonCppArrayValueIterator end() const;
+
+    /// Return the number of elements in the array.
+    size_t size() const
+    {
+        return m_value.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a JsonCpp value that is an empty array.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const Json::Value & emptyArray()
+    {
+        static const Json::Value array(Json::arrayValue);
+        return array;
+    }
+
+    /// Reference to the contained array
+    const Json::Value &m_value;
+
+};
+
+/**
+ * @brief  Light weight wrapper for a JsonCpp object.
+ *
+ * This class is light weight wrapper for a JsonCpp object. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * JsonCpp object, assumed to be an object, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class JsonCppObject
+{
+public:
+
+    typedef JsonCppObjectMemberIterator const_iterator;
+    typedef JsonCppObjectMemberIterator iterator;
+
+    /// Construct a JsonCppObject referencing an empty object singleton.
+    JsonCppObject()
+      : m_value(emptyObject()) { }
+
+    /**
+     * @brief   Construct a JsonCppObject referencing a specific JsonCpp value.
+     *
+     * @param   value  reference to a JsonCpp value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an object.
+     */
+    JsonCppObject(const Json::Value &value)
+      : m_value(value)
+    {
+        if (!value.isObject()) {
+            throwRuntimeError("Value is not an object.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for this first object member
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying JsonCpp implementation.
+     */
+    JsonCppObjectMemberIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for an invalid object member that indicates
+     *          the end of the collection.
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying JsonCpp implementation.
+     */
+    JsonCppObjectMemberIterator end() const;
+
+    /**
+     * @brief   Return an iterator for a member/property with the given name
+     *
+     * @param   propertyName   Property name
+     *
+     * @returns a valid iterator if found, or an invalid iterator if not found
+     */
+    JsonCppObjectMemberIterator find(const std::string &propertyName) const;
+
+    /// Return the number of members in the object
+    size_t size() const
+    {
+        return m_value.size();
+    }
+
+private:
+
+    /// Return a reference to an empty JsonCpp object
+    static const Json::Value & emptyObject()
+    {
+        static const Json::Value object(Json::objectValue);
+        return object;
+    }
+
+    /// Reference to the contained object
+    const Json::Value &m_value;
+};
+
+/**
+ * @brief   Stores an independent copy of a JsonCpp value.
+ *
+ * This class allows a JsonCpp value to be stored independent of its original
+ * document. JsonCpp makes this easy to do, as it does not perform any
+ * custom memory management.
+ *
+ * @see FrozenValue
+ */
+class JsonCppFrozenValue: public FrozenValue
+{
+public:
+
+    /**
+     * @brief  Make a copy of a JsonCpp value
+     *
+     * @param  source  the JsonCpp value to be copied
+     */
+    explicit JsonCppFrozenValue(const Json::Value &source)
+      : m_value(source) { }
+
+    FrozenValue * clone() const override
+    {
+        return new JsonCppFrozenValue(m_value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+
+    /// Stored JsonCpp value
+    Json::Value m_value;
+};
+
+/**
+ * @brief   Light weight wrapper for a JsonCpp value.
+ *
+ * This class is passed as an argument to the BasicAdapter template class,
+ * and is used to provide access to a JsonCpp value. This class is responsible
+ * for the mechanics of actually reading a JsonCpp value, whereas the
+ * BasicAdapter class is responsible for the semantics of type comparisons
+ * and conversions.
+ *
+ * The functions that need to be provided by this class are defined implicitly
+ * by the implementation of the BasicAdapter template class.
+ *
+ * @see BasicAdapter
+ */
+class JsonCppValue
+{
+public:
+
+    /// Construct a wrapper for the empty object singleton
+    JsonCppValue()
+      : m_value(emptyObject()) { }
+
+    /// Construct a wrapper for a specific JsonCpp value
+    JsonCppValue(const Json::Value &value)
+      : m_value(value) { }
+
+    /**
+     * @brief   Create a new JsonCppFrozenValue instance that contains the
+     *          value referenced by this JsonCppValue instance.
+     *
+     * @returns pointer to a new JsonCppFrozenValue instance, belonging to the
+     *          caller.
+     */
+    FrozenValue * freeze() const
+    {
+        return new JsonCppFrozenValue(m_value);
+    }
+
+    /**
+     * @brief   Optionally return a JsonCppArray instance.
+     *
+     * If the referenced JsonCpp value is an array, this function will return a
+     * std::optional containing a JsonCppArray instance referencing the
+     * array.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<JsonCppArray> getArrayOptional() const
+    {
+        if (m_value.isArray()) {
+            return opt::make_optional(JsonCppArray(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of elements in the array
+     *
+     * If the referenced JsonCpp value is an array, this function will retrieve
+     * the number of elements in the array and store it in the output variable
+     * provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of elements was retrieved, false otherwise.
+     */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_value.isArray()) {
+            result = m_value.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getBool(bool &result) const
+    {
+        if (m_value.isBool()) {
+            result = m_value.asBool();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getDouble(double &result) const
+    {
+        if (m_value.isDouble()) {
+            result = m_value.asDouble();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getInteger(int64_t &result) const
+    {
+        if (m_value.isIntegral()) {
+            result = static_cast<int64_t>(m_value.asInt());
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Optionally return a JsonCppObject instance.
+     *
+     * If the referenced JsonCpp value is an object, this function will return a
+     * std::optional containing a JsonCppObject instance referencing the
+     * object.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<JsonCppObject> getObjectOptional() const
+    {
+        if (m_value.isObject()) {
+            return opt::make_optional(JsonCppObject(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of members in the object
+     *
+     * If the referenced JsonCpp value is an object, this function will retrieve
+     * the number of members in the object and store it in the output variable
+     * provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of members was retrieved, false otherwise.
+     */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_value.isObject()) {
+            result = m_value.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value.isString()) {
+            result = m_value.asString();
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return true;
+    }
+
+    bool isArray() const
+    {
+        return m_value.isArray() && !m_value.isNull();
+    }
+
+    bool isBool() const
+    {
+        return m_value.isBool();
+    }
+
+    bool isDouble() const
+    {
+        return m_value.isDouble();
+    }
+
+    bool isInteger() const
+    {
+        return m_value.isIntegral() && !m_value.isBool();
+    }
+
+    bool isNull() const
+    {
+        return m_value.isNull();
+    }
+
+    bool isNumber() const
+    {
+        return m_value.isNumeric()  && !m_value.isBool();
+    }
+
+    bool isObject() const
+    {
+        return m_value.isObject() && !m_value.isNull();
+    }
+
+    bool isString() const
+    {
+        return m_value.isString();
+    }
+
+private:
+
+    /// Return a reference to an empty object singleton.
+    static const Json::Value &emptyObject()
+    {
+        static Json::Value object(Json::objectValue);
+        return object;
+    }
+
+    /// Reference to the contained JsonCpp value
+    const Json::Value &m_value;
+};
+
+/**
+ * @brief   An implementation of the Adapter interface supporting JsonCpp.
+ *
+ * This class is defined in terms of the BasicAdapter template class, which
+ * helps to ensure that all of the Adapter implementations behave consistently.
+ *
+ * @see Adapter
+ * @see BasicAdapter
+ */
+class JsonCppAdapter:
+    public BasicAdapter<JsonCppAdapter,
+                        JsonCppArray,
+                        JsonCppObjectMember,
+                        JsonCppObject,
+                        JsonCppValue>
+{
+public:
+
+    /// Construct a JsonCppAdapter that contains an empty object
+    JsonCppAdapter()
+      : BasicAdapter() { }
+
+    /// Construct a JsonCppAdapter containing a specific JsonCpp value
+    JsonCppAdapter(const Json::Value &value)
+      : BasicAdapter(value) { }
+};
+
+/**
+ * @brief   Class for iterating over values held in a JSON array.
+ *
+ * This class provides a JSON array iterator that dereferences as an instance of
+ * JsonCppAdapter representing a value stored in the array. It has been
+ * implemented using the boost iterator_facade template.
+ *
+ * @see JsonCppArray
+ */
+class JsonCppArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = JsonCppAdapter;
+    using difference_type = JsonCppAdapter;
+    using pointer = JsonCppAdapter*;
+    using reference = JsonCppAdapter&;
+
+    /**
+     * @brief   Construct a new JsonCppArrayValueIterator using an existing
+     *          JsonCpp iterator.
+     *
+     * @param   itr  JsonCpp iterator to store
+     */
+    JsonCppArrayValueIterator(const Json::Value::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /// Returns a JsonCppAdapter that contains the value of the current element.
+    JsonCppAdapter operator*() const
+    {
+        return JsonCppAdapter(*m_itr);
+    }
+
+    DerefProxy<JsonCppAdapter> operator->() const
+    {
+        return DerefProxy<JsonCppAdapter>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator against another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   rhs  iterator to compare against
+     *
+     * @returns true if the iterators are equal, false otherwise.
+     */
+    bool operator==(const JsonCppArrayValueIterator &rhs) const
+    {
+        return m_itr == rhs.m_itr;
+    }
+
+    bool operator!=(const JsonCppArrayValueIterator &rhs) const
+    {
+        return !(m_itr == rhs.m_itr);
+    }
+
+    JsonCppArrayValueIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    JsonCppArrayValueIterator operator++(int)
+    {
+        JsonCppArrayValueIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    JsonCppArrayValueIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        if (n > 0) {
+            while (n-- > 0) {
+                m_itr++;
+            }
+        } else {
+            while (n++ < 0) {
+                m_itr--;
+            }
+        }
+    }
+
+private:
+
+    Json::Value::const_iterator m_itr;
+};
+
+/**
+ * @brief   Class for iterating over the members belonging to a JSON object.
+ *
+ * This class provides a JSON object iterator that dereferences as an instance
+ * of JsonCppObjectMember representing one of the members of the object. It has
+ * been implemented using the boost iterator_facade template.
+ *
+ * @see JsonCppObject
+ * @see JsonCppObjectMember
+ */
+class JsonCppObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = JsonCppObjectMember;
+    using difference_type = JsonCppObjectMember;
+    using pointer = JsonCppObjectMember*;
+    using reference = JsonCppObjectMember&;
+
+    /**
+     * @brief   Construct an iterator from a JsonCpp iterator.
+     *
+     * @param   itr  JsonCpp iterator to store
+     */
+    JsonCppObjectMemberIterator(const Json::ValueConstIterator &itr)
+      : m_itr(itr) { }
+
+    /**
+     * @brief   Returns a JsonCppObjectMember that contains the key and value
+     *          belonging to the object member identified by the iterator.
+     */
+    JsonCppObjectMember operator*() const
+    {
+        return JsonCppObjectMember(m_itr.key().asString(), *m_itr);
+    }
+
+    DerefProxy<JsonCppObjectMember> operator->() const
+    {
+        return DerefProxy<JsonCppObjectMember>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator with another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   rhs  Iterator to compare with
+     *
+     * @returns true if the underlying iterators are equal, false otherwise
+     */
+    bool operator==(const JsonCppObjectMemberIterator &rhs) const
+    {
+        return m_itr == rhs.m_itr;
+    }
+
+    bool operator!=(const JsonCppObjectMemberIterator &rhs) const
+    {
+        return !(m_itr == rhs.m_itr);
+    }
+
+    const JsonCppObjectMemberIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    JsonCppObjectMemberIterator operator++(int)
+    {
+        JsonCppObjectMemberIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    JsonCppObjectMemberIterator operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+private:
+
+    /// Iternal copy of the original JsonCpp iterator
+    Json::ValueConstIterator m_itr;
+};
+
+/// Specialisation of the AdapterTraits template struct for JsonCppAdapter.
+template<>
+struct AdapterTraits<valijson::adapters::JsonCppAdapter>
+{
+    typedef Json::Value DocumentType;
+
+    static std::string adapterName()
+    {
+        return "JsonCppAdapter";
+    }
+};
+
+inline bool JsonCppFrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return JsonCppAdapter(m_value).equalTo(other, strict);
+}
+
+inline JsonCppArrayValueIterator JsonCppArray::begin() const
+{
+    return m_value.begin();
+}
+
+inline JsonCppArrayValueIterator JsonCppArray::end() const
+{
+    return m_value.end();
+}
+
+inline JsonCppObjectMemberIterator JsonCppObject::begin() const
+{
+    return m_value.begin();
+}
+
+inline JsonCppObjectMemberIterator JsonCppObject::end() const
+{
+    return m_value.end();
+}
+
+inline JsonCppObjectMemberIterator JsonCppObject::find(
+    const std::string &propertyName) const
+{
+    if (m_value.isMember(propertyName)) {
+        Json::ValueConstIterator itr;
+        for (itr = m_value.begin(); itr != m_value.end(); ++itr) {
+            if (itr.key() == propertyName) {
+                return itr;
+            }
+        }
+    }
+
+    return m_value.end();
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/nlohmann_json_adapter.hpp b/subprojects/valijson/include/valijson/adapters/nlohmann_json_adapter.hpp
new file mode 100644
index 000000000..aeb156476
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/nlohmann_json_adapter.hpp
@@ -0,0 +1,713 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation for the nlohmann json parser library.
+ *
+ * Include this file in your program to enable support for nlohmann json.
+ *
+ * This file defines the following classes (not in this order):
+ *  - NlohmannJsonAdapter
+ *  - NlohmannJsonArray
+ *  - NlohmannJsonValueIterator
+ *  - NlohmannJsonFrozenValue
+ *  - NlohmannJsonObject
+ *  - NlohmannJsonObjectMember
+ *  - NlohmannJsonObjectMemberIterator
+ *  - NlohmannJsonValue
+ *
+ * Due to the dependencies that exist between these classes, the ordering of
+ * class declarations and definitions may be a bit confusing. The best place to
+ * start is NlohmannJsonAdapter. This class definition is actually very small,
+ * since most of the functionality is inherited from the BasicAdapter class.
+ * Most of the classes in this file are provided as template arguments to the
+ * inherited BasicAdapter class.
+ */
+
+#pragma once
+
+#include <string>
+#include <nlohmann/json.hpp>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/exceptions.hpp>
+#include <utility>
+
+namespace valijson {
+namespace adapters {
+
+class NlohmannJsonAdapter;
+class NlohmannJsonArrayValueIterator;
+class NlohmannJsonObjectMemberIterator;
+
+typedef std::pair<std::string, NlohmannJsonAdapter> NlohmannJsonObjectMember;
+
+/**
+ * @brief  Light weight wrapper for a NlohmannJson array value.
+ *
+ * This class is light weight wrapper for a NlohmannJson array. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * NlohmannJson value, assumed to be an array, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class NlohmannJsonArray
+{
+public:
+
+    typedef NlohmannJsonArrayValueIterator const_iterator;
+    typedef NlohmannJsonArrayValueIterator iterator;
+
+    /// Construct a NlohmannJsonArray referencing an empty array.
+    NlohmannJsonArray()
+      : m_value(emptyArray()) { }
+
+    /**
+     * @brief   Construct a NlohmannJsonArray referencing a specific NlohmannJson
+     *          value.
+     *
+     * @param   value   reference to a NlohmannJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an array.
+     */
+    NlohmannJsonArray(const nlohmann::json &value)
+      : m_value(value)
+    {
+        if (!value.is_array()) {
+            throwRuntimeError("Value is not an array.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for the first element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying NlohmannJson implementation.
+     */
+    NlohmannJsonArrayValueIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for one-past the last element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying NlohmannJson implementation.
+     */
+    NlohmannJsonArrayValueIterator end() const;
+
+    /// Return the number of elements in the array
+    size_t size() const
+    {
+        return m_value.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a NlohmannJson value that is an empty array.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const nlohmann::json & emptyArray()
+    {
+        static const nlohmann::json array = nlohmann::json::array();
+        return array;
+    }
+
+    /// Reference to the contained value
+    const nlohmann::json &m_value;
+};
+
+/**
+ * @brief  Light weight wrapper for a NlohmannJson object.
+ *
+ * This class is light weight wrapper for a NlohmannJson object. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * NlohmannJson value, assumed to be an object, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class NlohmannJsonObject
+{
+public:
+
+    typedef NlohmannJsonObjectMemberIterator const_iterator;
+    typedef NlohmannJsonObjectMemberIterator iterator;
+
+    /// Construct a NlohmannJsonObject referencing an empty object singleton.
+    NlohmannJsonObject()
+      : m_value(emptyObject()) { }
+
+    /**
+     * @brief   Construct a NlohmannJsonObject referencing a specific NlohmannJson
+     *          value.
+     *
+     * @param   value  reference to a NlohmannJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an object.
+     */
+    NlohmannJsonObject(const nlohmann::json &value)
+      : m_value(value)
+    {
+        if (!value.is_object()) {
+            throwRuntimeError("Value is not an object.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for this first object member
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying NlohmannJson implementation.
+     */
+    NlohmannJsonObjectMemberIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for an invalid object member that indicates
+     *          the end of the collection.
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying NlohmannJson implementation.
+     */
+    NlohmannJsonObjectMemberIterator end() const;
+
+    /**
+     * @brief   Return an iterator for the object member with the specified
+     *          property name.
+     *
+     * If an object member with the specified name does not exist, the iterator
+     * returned will be the same as the iterator returned by the end() function.
+     *
+     * @param   propertyName  property name to search for
+     */
+    NlohmannJsonObjectMemberIterator find(const std::string &propertyName) const;
+
+    /// Returns the number of members belonging to this object.
+    size_t size() const
+    {
+        return m_value.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a NlohmannJson value that is empty object.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const nlohmann::json & emptyObject()
+    {
+        static const nlohmann::json object = nlohmann::json::object();
+        return object;
+    }
+
+    /// Reference to the contained object
+    const nlohmann::json &m_value;
+};
+
+
+/**
+ * @brief   Stores an independent copy of a NlohmannJson value.
+ *
+ * This class allows a NlohmannJson value to be stored independent of its original
+ * document. NlohmannJson makes this easy to do, as it does not perform any
+ * custom memory management.
+ *
+ * @see FrozenValue
+ */
+class NlohmannJsonFrozenValue: public FrozenValue
+{
+public:
+
+    /**
+     * @brief  Make a copy of a NlohmannJson value
+     *
+     * @param  source  the NlohmannJson value to be copied
+     */
+    explicit NlohmannJsonFrozenValue(nlohmann::json source)
+      : m_value(std::move(source)) { }
+
+    FrozenValue * clone() const override
+    {
+        return new NlohmannJsonFrozenValue(m_value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+
+    /// Stored NlohmannJson value
+    nlohmann::json m_value;
+};
+
+
+/**
+ * @brief   Light weight wrapper for a NlohmannJson value.
+ *
+ * This class is passed as an argument to the BasicAdapter template class,
+ * and is used to provide access to a NlohmannJson value. This class is responsible
+ * for the mechanics of actually reading a NlohmannJson value, whereas the
+ * BasicAdapter class is responsible for the semantics of type comparisons
+ * and conversions.
+ *
+ * The functions that need to be provided by this class are defined implicitly
+ * by the implementation of the BasicAdapter template class.
+ *
+ * @see BasicAdapter
+ */
+class NlohmannJsonValue
+{
+public:
+
+    /// Construct a wrapper for the empty object singleton
+    NlohmannJsonValue()
+      : m_value(emptyObject()) { }
+
+    /// Construct a wrapper for a specific NlohmannJson value
+    NlohmannJsonValue(const nlohmann::json &value)
+      : m_value(value) { }
+
+    /**
+     * @brief   Create a new NlohmannJsonFrozenValue instance that contains the
+     *          value referenced by this NlohmannJsonValue instance.
+     *
+     * @returns pointer to a new NlohmannJsonFrozenValue instance, belonging to the
+     *          caller.
+     */
+    FrozenValue * freeze() const
+    {
+        return new NlohmannJsonFrozenValue(m_value);
+    }
+
+    /**
+     * @brief   Optionally return a NlohmannJsonArray instance.
+     *
+     * If the referenced NlohmannJson value is an array, this function will return
+     * a std::optional containing a NlohmannJsonArray instance referencing the
+     * array.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<NlohmannJsonArray> getArrayOptional() const
+    {
+        if (m_value.is_array()) {
+            return opt::make_optional(NlohmannJsonArray(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of elements in the array
+     *
+     * If the referenced NlohmannJson value is an array, this function will
+     * retrieve the number of elements in the array and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of elements was retrieved, false otherwise.
+     */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_value.is_array()) {
+            result = m_value.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getBool(bool &result) const
+    {
+        if (m_value.is_boolean()) {
+            result = m_value.get<bool>();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getDouble(double &result) const
+    {
+        if (m_value.is_number_float()) {
+            result = m_value.get<double>();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getInteger(int64_t &result) const
+    {
+        if(m_value.is_number_integer()) {
+            result = m_value.get<int64_t>();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * @brief   Optionally return a NlohmannJsonObject instance.
+     *
+     * If the referenced NlohmannJson value is an object, this function will return a
+     * std::optional containing a NlohmannJsonObject instance referencing the
+     * object.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<NlohmannJsonObject> getObjectOptional() const
+    {
+        if (m_value.is_object()) {
+            return opt::make_optional(NlohmannJsonObject(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of members in the object
+     *
+     * If the referenced NlohmannJson value is an object, this function will
+     * retrieve the number of members in the object and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of members was retrieved, false otherwise.
+     */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_value.is_object()) {
+            result = m_value.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value.is_string()) {
+            result = m_value.get<std::string>();
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return true;
+    }
+
+    bool isArray() const
+    {
+        return m_value.is_array();
+    }
+
+    bool isBool() const
+    {
+        return m_value.is_boolean();
+    }
+
+    bool isDouble() const
+    {
+        return m_value.is_number_float();
+    }
+
+    bool isInteger() const
+    {
+        return m_value.is_number_integer();
+    }
+
+    bool isNull() const
+    {
+        return m_value.is_null();
+    }
+
+    bool isNumber() const
+    {
+        return m_value.is_number();
+    }
+
+    bool isObject() const
+    {
+        return m_value.is_object();
+    }
+
+    bool isString() const
+    {
+        return m_value.is_string();
+    }
+
+private:
+
+    /// Return a reference to an empty object singleton
+    static const nlohmann::json & emptyObject()
+    {
+        static const nlohmann::json object = nlohmann::json::object();
+        return object;
+    }
+
+    /// Reference to the contained NlohmannJson value.
+    const nlohmann::json &m_value;
+};
+
+/**
+ * @brief   An implementation of the Adapter interface supporting NlohmannJson.
+ *
+ * This class is defined in terms of the BasicAdapter template class, which
+ * helps to ensure that all of the Adapter implementations behave consistently.
+ *
+ * @see Adapter
+ * @see BasicAdapter
+ */
+class NlohmannJsonAdapter:
+    public BasicAdapter<NlohmannJsonAdapter,
+        NlohmannJsonArray,
+        NlohmannJsonObjectMember,
+        NlohmannJsonObject,
+        NlohmannJsonValue>
+{
+public:
+    /// Construct a NlohmannJsonAdapter that contains an empty object
+    NlohmannJsonAdapter()
+      : BasicAdapter() { }
+
+    /// Construct a NlohmannJsonAdapter containing a specific Nlohmann Json object
+    NlohmannJsonAdapter(const nlohmann::json &value)
+      : BasicAdapter(NlohmannJsonValue{value}) { }
+};
+
+/**
+ * @brief   Class for iterating over values held in a JSON array.
+ *
+ * This class provides a JSON array iterator that dereferences as an instance of
+ * NlohmannJsonAdapter representing a value stored in the array. It has been
+ * implemented using the boost iterator_facade template.
+ *
+ * @see NlohmannJsonArray
+ */
+class NlohmannJsonArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = NlohmannJsonAdapter;
+    using difference_type = NlohmannJsonAdapter;
+    using pointer = NlohmannJsonAdapter*;
+    using reference = NlohmannJsonAdapter&;
+
+    /**
+     * @brief   Construct a new NlohmannJsonArrayValueIterator using an existing
+     *          NlohmannJson iterator.
+     *
+     * @param   itr  NlohmannJson iterator to store
+     */
+    NlohmannJsonArrayValueIterator(const nlohmann::json::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /// Returns a NlohmannJsonAdapter that contains the value of the current
+    /// element.
+    NlohmannJsonAdapter operator*() const
+    {
+        return NlohmannJsonAdapter(*m_itr);
+    }
+
+    DerefProxy<NlohmannJsonAdapter> operator->() const
+    {
+        return DerefProxy<NlohmannJsonAdapter>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator against another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  iterator to compare against
+     *
+     * @returns true   if the iterators are equal, false otherwise.
+     */
+    bool operator==(const NlohmannJsonArrayValueIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const NlohmannJsonArrayValueIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const NlohmannJsonArrayValueIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    NlohmannJsonArrayValueIterator operator++(int)
+    {
+        NlohmannJsonArrayValueIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const NlohmannJsonArrayValueIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        m_itr += n;
+    }
+
+private:
+    nlohmann::json::const_iterator m_itr;
+};
+
+
+/**
+ * @brief   Class for iterating over the members belonging to a JSON object.
+ *
+ * This class provides a JSON object iterator that dereferences as an instance
+ * of NlohmannJsonObjectMember representing one of the members of the object. It
+ * has been implemented using the boost iterator_facade template.
+ *
+ * @see NlohmannJsonObject
+ * @see NlohmannJsonObjectMember
+ */
+class NlohmannJsonObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = NlohmannJsonObjectMember;
+    using difference_type = NlohmannJsonObjectMember;
+    using pointer = NlohmannJsonObjectMember*;
+    using reference = NlohmannJsonObjectMember&;
+
+    /**
+     * @brief   Construct an iterator from a NlohmannJson iterator.
+     *
+     * @param   itr  NlohmannJson iterator to store
+     */
+    NlohmannJsonObjectMemberIterator(const nlohmann::json::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /**
+     * @brief   Returns a NlohmannJsonObjectMember that contains the key and value
+     *          belonging to the object member identified by the iterator.
+     */
+    NlohmannJsonObjectMember operator*() const
+    {
+        return NlohmannJsonObjectMember(m_itr.key(), m_itr.value());
+    }
+
+    DerefProxy<NlohmannJsonObjectMember> operator->() const
+    {
+        return DerefProxy<NlohmannJsonObjectMember>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator with another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  Iterator to compare with
+     *
+     * @returns true if the underlying iterators are equal, false otherwise
+     */
+    bool operator==(const NlohmannJsonObjectMemberIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const NlohmannJsonObjectMemberIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const NlohmannJsonObjectMemberIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    NlohmannJsonObjectMemberIterator operator++(int)
+    {
+        NlohmannJsonObjectMemberIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const NlohmannJsonObjectMemberIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+private:
+
+    /// Iternal copy of the original NlohmannJson iterator
+    nlohmann::json::const_iterator m_itr;
+};
+
+/// Specialisation of the AdapterTraits template struct for NlohmannJsonAdapter.
+template<>
+struct AdapterTraits<valijson::adapters::NlohmannJsonAdapter>
+{
+    typedef nlohmann::json DocumentType;
+
+    static std::string adapterName()
+    {
+        return "NlohmannJsonAdapter";
+    }
+};
+
+inline bool NlohmannJsonFrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return NlohmannJsonAdapter(m_value).equalTo(other, strict);
+}
+
+inline NlohmannJsonArrayValueIterator NlohmannJsonArray::begin() const
+{
+    return m_value.begin();
+}
+
+inline NlohmannJsonArrayValueIterator NlohmannJsonArray::end() const
+{
+    return m_value.end();
+}
+
+inline NlohmannJsonObjectMemberIterator NlohmannJsonObject::begin() const
+{
+    return m_value.begin();
+}
+
+inline NlohmannJsonObjectMemberIterator NlohmannJsonObject::end() const
+{
+    return m_value.end();
+}
+
+inline NlohmannJsonObjectMemberIterator NlohmannJsonObject::find(
+        const std::string &propertyName) const
+{
+    return m_value.find(propertyName);
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/picojson_adapter.hpp b/subprojects/valijson/include/valijson/adapters/picojson_adapter.hpp
new file mode 100644
index 000000000..4f5e5b6b7
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/picojson_adapter.hpp
@@ -0,0 +1,732 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation for the PicoJson parser library.
+ *
+ * Include this file in your program to enable support for PicoJson.
+ *
+ * This file defines the following classes (not in this order):
+ *  - PicoJsonAdapter
+ *  - PicoJsonArray
+ *  - PicoJsonArrayValueIterator
+ *  - PicoJsonFrozenValue
+ *  - PicoJsonObject
+ *  - PicoJsonObjectMember
+ *  - PicoJsonObjectMemberIterator
+ *  - PicoJsonValue
+ *
+ * Due to the dependencies that exist between these classes, the ordering of
+ * class declarations and definitions may be a bit confusing. The best place to
+ * start is PicoJsonAdapter. This class definition is actually very small,
+ * since most of the functionality is inherited from the BasicAdapter class.
+ * Most of the classes in this file are provided as template arguments to the
+ * inherited BasicAdapter class.
+ */
+
+#pragma once
+
+#include <string>
+
+#ifdef _MSC_VER
+#pragma warning(disable: 4706)
+#include <picojson.h>
+#pragma warning(default: 4706)
+#else
+#include <picojson.h>
+#endif
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+class PicoJsonAdapter;
+class PicoJsonArrayValueIterator;
+class PicoJsonObjectMemberIterator;
+
+typedef std::pair<std::string, PicoJsonAdapter> PicoJsonObjectMember;
+
+/**
+ * @brief  Light weight wrapper for a PicoJson array value.
+ *
+ * This class is light weight wrapper for a PicoJson array. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * PicoJson value, assumed to be an array, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class PicoJsonArray
+{
+public:
+
+    typedef PicoJsonArrayValueIterator const_iterator;
+    typedef PicoJsonArrayValueIterator iterator;
+
+    /// Construct a PicoJsonArray referencing an empty array.
+    PicoJsonArray()
+      : m_value(emptyArray()) { }
+
+    /**
+     * @brief   Construct a PicoJsonArray referencing a specific PicoJson
+     *          value.
+     *
+     * @param   value   reference to a PicoJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an array.
+     */
+    explicit PicoJsonArray(const picojson::value &value)
+      : m_value(value)
+    {
+        if (!value.is<picojson::array>()) {
+            throwRuntimeError("Value is not an array.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for the first element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying PicoJson implementation.
+     */
+    PicoJsonArrayValueIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for one-past the last element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying PicoJson implementation.
+     */
+    PicoJsonArrayValueIterator end() const;
+
+    /// Return the number of elements in the array
+    size_t size() const
+    {
+        const picojson::array &array = m_value.get<picojson::array>();
+        return array.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a PicoJson value that is an empty array.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const picojson::value & emptyArray()
+    {
+        static const picojson::value array(picojson::array_type, false);
+        return array;
+    }
+
+    /// Reference to the contained value
+    const picojson::value &m_value;
+};
+
+/**
+ * @brief  Light weight wrapper for a PicoJson object.
+ *
+ * This class is light weight wrapper for a PicoJson object. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * PicoJson value, assumed to be an object, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class PicoJsonObject
+{
+public:
+
+    typedef PicoJsonObjectMemberIterator const_iterator;
+    typedef PicoJsonObjectMemberIterator iterator;
+
+    /// Construct a PicoJsonObject referencing an empty object singleton.
+    PicoJsonObject()
+      : m_value(emptyObject()) { }
+
+    /**
+     * @brief   Construct a PicoJsonObject referencing a specific PicoJson
+     *          value.
+     *
+     * @param   value  reference to a PicoJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an object.
+     */
+    PicoJsonObject(const picojson::value &value)
+      : m_value(value)
+    {
+        if (!value.is<picojson::object>()) {
+            throwRuntimeError("Value is not an object.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for this first object member
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying PicoJson implementation.
+     */
+    PicoJsonObjectMemberIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for an invalid object member that indicates
+     *          the end of the collection.
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying PicoJson implementation.
+     */
+    PicoJsonObjectMemberIterator end() const;
+
+    /**
+     * @brief   Return an iterator for the object member with the specified
+     *          property name.
+     *
+     * If an object member with the specified name does not exist, the iterator
+     * returned will be the same as the iterator returned by the end() function.
+     *
+     * @param   propertyName  property name to search for
+     */
+    PicoJsonObjectMemberIterator find(const std::string &propertyName) const;
+
+    /// Returns the number of members belonging to this object.
+    size_t size() const
+    {
+        const picojson::object &object = m_value.get<picojson::object>();
+        return object.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a PicoJson value that is empty object.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const picojson::value & emptyObject()
+    {
+        static const picojson::value object(picojson::object_type, false);
+        return object;
+    }
+
+    /// Reference to the contained object
+    const picojson::value &m_value;
+};
+
+/**
+ * @brief   Stores an independent copy of a PicoJson value.
+ *
+ * This class allows a PicoJson value to be stored independent of its original
+ * document. PicoJson makes this easy to do, as it does not perform any
+ * custom memory management.
+ *
+ * @see FrozenValue
+ */
+class PicoJsonFrozenValue: public FrozenValue
+{
+public:
+
+    /**
+     * @brief  Make a copy of a PicoJson value
+     *
+     * @param  source  the PicoJson value to be copied
+     */
+    explicit PicoJsonFrozenValue(const picojson::value &source)
+      : m_value(source) { }
+
+    FrozenValue * clone() const override
+    {
+        return new PicoJsonFrozenValue(m_value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+
+    /// Stored PicoJson value
+    picojson::value m_value;
+};
+
+/**
+ * @brief   Light weight wrapper for a PicoJson value.
+ *
+ * This class is passed as an argument to the BasicAdapter template class,
+ * and is used to provide access to a PicoJson value. This class is responsible
+ * for the mechanics of actually reading a PicoJson value, whereas the
+ * BasicAdapter class is responsible for the semantics of type comparisons
+ * and conversions.
+ *
+ * The functions that need to be provided by this class are defined implicitly
+ * by the implementation of the BasicAdapter template class.
+ *
+ * @see BasicAdapter
+ */
+class PicoJsonValue
+{
+public:
+
+    /// Construct a wrapper for the empty object singleton
+    PicoJsonValue()
+      : m_value(emptyObject()) { }
+
+    /// Construct a wrapper for a specific PicoJson value
+    PicoJsonValue(const picojson::value &value)
+      : m_value(value) { }
+
+    /**
+     * @brief   Create a new PicoJsonFrozenValue instance that contains the
+     *          value referenced by this PicoJsonValue instance.
+     *
+     * @returns pointer to a new PicoJsonFrozenValue instance, belonging to the
+     *          caller.
+     */
+    FrozenValue * freeze() const
+    {
+        return new PicoJsonFrozenValue(m_value);
+    }
+
+    /**
+     * @brief   Optionally return a PicoJsonArray instance.
+     *
+     * If the referenced PicoJson value is an array, this function will return
+     * a std::optional containing a PicoJsonArray instance referencing the
+     * array.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<PicoJsonArray> getArrayOptional() const
+    {
+        if (m_value.is<picojson::array>()) {
+            return opt::make_optional(PicoJsonArray(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of elements in the array
+     *
+     * If the referenced PicoJson value is an array, this function will
+     * retrieve the number of elements in the array and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of elements was retrieved, false otherwise.
+     */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_value.is<picojson::array>()) {
+            const picojson::array& array = m_value.get<picojson::array>();
+            result = array.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getBool(bool &result) const
+    {
+        if (m_value.is<bool>()) {
+            result = m_value.get<bool>();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getDouble(double &result) const
+    {
+        if (m_value.is<double>()) {
+            result = m_value.get<double>();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getInteger(int64_t &result) const
+    {
+        if (m_value.is<int64_t>()) {
+            result = m_value.get<int64_t>();
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Optionally return a PicoJsonObject instance.
+     *
+     * If the referenced PicoJson value is an object, this function will return a
+     * std::optional containing a PicoJsonObject instance referencing the
+     * object.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<PicoJsonObject> getObjectOptional() const
+    {
+        if (m_value.is<picojson::object>()) {
+            return opt::make_optional(PicoJsonObject(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of members in the object
+     *
+     * If the referenced PicoJson value is an object, this function will
+     * retrieve the number of members in the object and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of members was retrieved, false otherwise.
+     */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_value.is<picojson::object>()) {
+            const picojson::object &object = m_value.get<picojson::object>();
+            result = object.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value.is<std::string>()) {
+            result = m_value.get<std::string>();
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return true;
+    }
+
+    bool isArray() const
+    {
+        return m_value.is<picojson::array>();
+    }
+
+    bool isBool() const
+    {
+        return m_value.is<bool>();
+    }
+
+    bool isDouble() const
+    {
+        if (m_value.is<int64_t>()) {
+            return false;
+        }
+
+        return m_value.is<double>();
+    }
+
+    bool isInteger() const
+    {
+        return m_value.is<int64_t>();
+    }
+
+    bool isNull() const
+    {
+        return m_value.is<picojson::null>();
+    }
+
+    bool isNumber() const
+    {
+        return m_value.is<double>();
+    }
+
+    bool isObject() const
+    {
+        return m_value.is<picojson::object>();
+    }
+
+    bool isString() const
+    {
+        return m_value.is<std::string>();
+    }
+
+private:
+
+    /// Return a reference to an empty object singleton
+    static const picojson::value & emptyObject()
+    {
+        static const picojson::value object(picojson::object_type, false);
+        return object;
+    }
+
+    /// Reference to the contained PicoJson value.
+    const picojson::value &m_value;
+};
+
+/**
+ * @brief   An implementation of the Adapter interface supporting PicoJson.
+ *
+ * This class is defined in terms of the BasicAdapter template class, which
+ * helps to ensure that all of the Adapter implementations behave consistently.
+ *
+ * @see Adapter
+ * @see BasicAdapter
+ */
+class PicoJsonAdapter:
+    public BasicAdapter<PicoJsonAdapter,
+                        PicoJsonArray,
+                        PicoJsonObjectMember,
+                        PicoJsonObject,
+                        PicoJsonValue>
+{
+public:
+
+    /// Construct a PicoJsonAdapter that contains an empty object
+    PicoJsonAdapter()
+      : BasicAdapter() { }
+
+    /// Construct a PicoJsonAdapter containing a specific PicoJson value
+    PicoJsonAdapter(const picojson::value &value)
+      : BasicAdapter(value) { }
+};
+
+/**
+ * @brief   Class for iterating over values held in a JSON array.
+ *
+ * This class provides a JSON array iterator that dereferences as an instance of
+ * PicoJsonAdapter representing a value stored in the array. It has been
+ * implemented using the std::iterator template.
+ *
+ * @see PicoJsonArray
+ */
+class PicoJsonArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = PicoJsonAdapter;
+    using difference_type = PicoJsonAdapter;
+    using pointer = PicoJsonAdapter*;
+    using reference = PicoJsonAdapter&;
+
+    /**
+     * @brief   Construct a new PicoJsonArrayValueIterator using an existing
+     *          PicoJson iterator.
+     *
+     * @param   itr  PicoJson iterator to store
+     */
+    PicoJsonArrayValueIterator(const picojson::array::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /// Returns a PicoJsonAdapter that contains the value of the current
+    /// element.
+    PicoJsonAdapter operator*() const
+    {
+        return PicoJsonAdapter(*m_itr);
+    }
+
+    DerefProxy<PicoJsonAdapter> operator->() const
+    {
+        return DerefProxy<PicoJsonAdapter>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator against another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  iterator to compare against
+     *
+     * @returns true   if the iterators are equal, false otherwise.
+     */
+    bool operator==(const PicoJsonArrayValueIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const PicoJsonArrayValueIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const PicoJsonArrayValueIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    PicoJsonArrayValueIterator operator++(int)
+    {
+        PicoJsonArrayValueIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const PicoJsonArrayValueIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        m_itr += n;
+    }
+
+private:
+
+    picojson::array::const_iterator m_itr;
+};
+
+/**
+ * @brief   Class for iterating over the members belonging to a JSON object.
+ *
+ * This class provides a JSON object iterator that dereferences as an instance
+ * of PicoJsonObjectMember representing one of the members of the object. It
+ * has been implemented using the boost iterator_facade template.
+ *
+ * @see PicoJsonObject
+ * @see PicoJsonObjectMember
+ */
+class PicoJsonObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = PicoJsonObjectMember;
+    using difference_type = PicoJsonObjectMember;
+    using pointer = PicoJsonObjectMember*;
+    using reference = PicoJsonObjectMember&;
+
+    /**
+     * @brief   Construct an iterator from a PicoJson iterator.
+     *
+     * @param   itr  PicoJson iterator to store
+     */
+    PicoJsonObjectMemberIterator(const picojson::object::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /**
+     * @brief   Returns a PicoJsonObjectMember that contains the key and value
+     *          belonging to the object member identified by the iterator.
+     */
+    PicoJsonObjectMember operator*() const
+    {
+        return PicoJsonObjectMember(m_itr->first, m_itr->second);
+    }
+
+    DerefProxy<PicoJsonObjectMember> operator->() const
+    {
+        return DerefProxy<PicoJsonObjectMember>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator with another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  Iterator to compare with
+     *
+     * @returns true if the underlying iterators are equal, false otherwise
+     */
+    bool operator==(const PicoJsonObjectMemberIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const PicoJsonObjectMemberIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const PicoJsonObjectMemberIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    PicoJsonObjectMemberIterator operator++(int)
+    {
+        PicoJsonObjectMemberIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const PicoJsonObjectMemberIterator& operator--(int)
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+private:
+
+    /// Iternal copy of the original PicoJson iterator
+    picojson::object::const_iterator m_itr;
+};
+
+/// Specialisation of the AdapterTraits template struct for PicoJsonAdapter.
+template<>
+struct AdapterTraits<valijson::adapters::PicoJsonAdapter>
+{
+    typedef picojson::value DocumentType;
+
+    static std::string adapterName()
+    {
+        return "PicoJsonAdapter";
+    }
+};
+
+inline bool PicoJsonFrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return PicoJsonAdapter(m_value).equalTo(other, strict);
+}
+
+inline PicoJsonArrayValueIterator PicoJsonArray::begin() const
+{
+    const picojson::array &array = m_value.get<picojson::array>();
+    return array.begin();
+}
+
+inline PicoJsonArrayValueIterator PicoJsonArray::end() const
+{
+    const picojson::array &array = m_value.get<picojson::array>();
+    return array.end();
+}
+
+inline PicoJsonObjectMemberIterator PicoJsonObject::begin() const
+{
+    const picojson::object &object = m_value.get<picojson::object>();
+    return object.begin();
+}
+
+inline PicoJsonObjectMemberIterator PicoJsonObject::end() const
+{
+    const picojson::object &object = m_value.get<picojson::object>();
+    return object.end();
+}
+
+inline PicoJsonObjectMemberIterator PicoJsonObject::find(
+    const std::string &propertyName) const
+{
+    const picojson::object &object = m_value.get<picojson::object>();
+    return object.find(propertyName);
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/poco_json_adapter.hpp b/subprojects/valijson/include/valijson/adapters/poco_json_adapter.hpp
new file mode 100644
index 000000000..a997debfa
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/poco_json_adapter.hpp
@@ -0,0 +1,720 @@
+/**
+* @file
+*
+* @brief   Adapter implementation for the Poco json parser library.
+*
+* Include this file in your program to enable support for Poco json.
+*
+* This file defines the following classes (not in this order):
+*  - PocoJsonAdapter
+*  - PocoJsonArray
+*  - PocoJsonValueIterator
+*  - PocoJsonFrozenValue
+*  - PocoJsonObject
+*  - PocoJsonObjectMember
+*  - PocoJsonObjectMemberIterator
+*  - PocoJsonValue
+*
+* Due to the dependencies that exist between these classes, the ordering of
+* class declarations and definitions may be a bit confusing. The best place to
+* start is PocoJsonAdapter. This class definition is actually very small,
+* since most of the functionality is inherited from the BasicAdapter class.
+* Most of the classes in this file are provided as template arguments to the
+* inherited BasicAdapter class.
+*/
+
+#pragma once
+
+#include <string>
+#include <Poco/JSON/Object.h>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+class PocoJsonAdapter;
+class PocoJsonArrayValueIterator;
+class PocoJsonObjectMemberIterator;
+
+typedef std::pair<std::string, PocoJsonAdapter> PocoJsonObjectMember;
+
+/**
+* @brief  Light weight wrapper for a PocoJson array value.
+*
+* This class is light weight wrapper for a PocoJson array. It provides a
+* minimum set of container functions and typedefs that allow it to be used as
+* an iterable container.
+*
+* An instance of this class contains a single reference to the underlying
+* PocoJson value, assumed to be an array, so there is very little overhead
+* associated with copy construction and passing by value.
+*/
+class PocoJsonArray
+{
+public:
+
+    typedef PocoJsonArrayValueIterator const_iterator;
+    typedef PocoJsonArrayValueIterator iterator;
+
+    /// Construct a PocoJsonArray referencing an empty array.
+    PocoJsonArray()
+        : m_value(emptyArray())
+    { }
+
+    /**
+    * @brief   Construct a PocoJsonArray referencing a specific PocoJson
+    *          value.
+    *
+    * @param   value   reference to a PocoJson value
+    *
+    * Note that this constructor will throw an exception if the value is not
+    * an array.
+    */
+    PocoJsonArray(const Poco::Dynamic::Var &value)
+        : m_value(value)
+    {
+        if (value.type() != typeid(Poco::JSON::Array::Ptr)) {
+            throwRuntimeError("Value is not an array.");
+        }
+    }
+
+    /**
+    * @brief   Return an iterator for the first element of the array.
+    *
+    * The iterator return by this function is effectively the iterator
+    * returned by the underlying PocoJson implementation.
+    */
+    PocoJsonArrayValueIterator begin() const;
+
+    /**
+    * @brief   Return an iterator for one-past the last element of the array.
+    *
+    * The iterator return by this function is effectively the iterator
+    * returned by the underlying PocoJson implementation.
+    */
+    PocoJsonArrayValueIterator end() const;
+
+    /// Return the number of elements in the array
+    size_t size() const
+    {
+        return m_value.extract<Poco::JSON::Array::Ptr>()->size();
+    }
+
+private:
+
+    /**
+    * @brief   Return a PocoJson value that is an empty array.
+    */
+    static Poco::Dynamic::Var emptyArray()
+    {
+        Poco::Dynamic::Var array = Poco::JSON::Array::Ptr();
+        return array;
+    }
+
+    /// Contained value
+    Poco::Dynamic::Var m_value;
+};
+
+/**
+* @brief  Light weight wrapper for a PocoJson object.
+*
+* This class is light weight wrapper for a PocoJson object. It provides a
+* minimum set of container functions and typedefs that allow it to be used as
+* an iterable container.
+*
+* An instance of this class contains a single reference to the underlying
+* PocoJson value, assumed to be an object, so there is very little overhead
+* associated with copy construction and passing by value.
+*/
+class PocoJsonObject
+{
+public:
+
+    typedef PocoJsonObjectMemberIterator const_iterator;
+    typedef PocoJsonObjectMemberIterator iterator;
+
+    /// Construct a PocoJsonObject an empty object.
+    PocoJsonObject()
+        : m_value(emptyObject())
+    { }
+
+    /**
+    * @brief   Construct a PocoJsonObject referencing a specific PocoJson
+    *          value.
+    *
+    * @param   value  reference to a PocoJson value
+    *
+    * Note that this constructor will throw an exception if the value is not
+    * an object.
+    */
+    PocoJsonObject(const Poco::Dynamic::Var &value)
+        : m_value(value)
+    {
+        if (value.type() != typeid(Poco::JSON::Object::Ptr)) {
+            throwRuntimeError("Value is not an object.");
+        }
+    }
+
+    /**
+    * @brief   Return an iterator for this first object member
+    *
+    * The iterator return by this function is effectively a wrapper around
+    * the iterator value returned by the underlying PocoJson implementation.
+    */
+    PocoJsonObjectMemberIterator begin() const;
+
+    /**
+    * @brief   Return an iterator for an invalid object member that indicates
+    *          the end of the collection.
+    *
+    * The iterator return by this function is effectively a wrapper around
+    * the iterator value returned by the underlying PocoJson implementation.
+    */
+    PocoJsonObjectMemberIterator end() const;
+
+    /**
+    * @brief   Return an iterator for the object member with the specified
+    *          property name.
+    *
+    * If an object member with the specified name does not exist, the iterator
+    * returned will be the same as the iterator returned by the end() function.
+    *
+    * @param   propertyName  property name to search for
+    */
+    PocoJsonObjectMemberIterator find(const std::string &propertyName) const;
+
+    /// Returns the number of members belonging to this object.
+    size_t size() const
+    {
+        return m_value.extract<Poco::JSON::Object::Ptr>()->size();
+    }
+
+private:
+
+    /**
+    * @brief   Return a PocoJson value that is empty object.
+    */
+    static Poco::Dynamic::Var emptyObject()
+    {
+        Poco::Dynamic::Var object = Poco::JSON::Object::Ptr();
+        return object;
+    }
+
+    /// Contained value
+    Poco::Dynamic::Var m_value;
+};
+
+/**
+* @brief   Stores an independent copy of a PocoJson value.
+*
+* This class allows a PocoJson value to be stored independent of its original
+* document. PocoJson makes this easy to do, as it does not perform any
+* custom memory management.
+*
+* @see FrozenValue
+*/
+class PocoJsonFrozenValue : public FrozenValue
+{
+public:
+
+    /**
+    * @brief  Make a copy of a PocoJson value
+    *
+    * @param  source  the PocoJson value to be copied
+    */
+    explicit PocoJsonFrozenValue(const Poco::Dynamic::Var &source)
+        : m_value(source)
+    { }
+
+    virtual FrozenValue * clone() const
+    {
+        return new PocoJsonFrozenValue(m_value);
+    }
+
+    virtual bool equalTo(const Adapter &other, bool strict) const;
+
+private:
+
+    /// Stored PocoJson value
+    Poco::Dynamic::Var m_value;
+};
+
+
+/**
+* @brief   Light weight wrapper for a PocoJson value.
+*
+* This class is passed as an argument to the BasicAdapter template class,
+* and is used to provide access to a PocoJson value. This class is responsible
+* for the mechanics of actually reading a PocoJson value, whereas the
+* BasicAdapter class is responsible for the semantics of type comparisons
+* and conversions.
+*
+* The functions that need to be provided by this class are defined implicitly
+* by the implementation of the BasicAdapter template class.
+*
+* @see BasicAdapter
+*/
+class PocoJsonValue
+{
+public:
+
+    /// Construct a wrapper for the empty object
+    PocoJsonValue()
+        : m_value(emptyObject())
+    { }
+
+    /// Construct a wrapper for a specific PocoJson value
+    PocoJsonValue(const Poco::Dynamic::Var& value)
+        : m_value(value)
+    { }
+
+    /**
+    * @brief   Create a new PocoJsonFrozenValue instance that contains the
+    *          value referenced by this PocoJsonValue instance.
+    *
+    * @returns pointer to a new PocoJsonFrozenValue instance, belonging to the
+    *          caller.
+    */
+    FrozenValue * freeze() const
+    {
+        return new PocoJsonFrozenValue(m_value);
+    }
+
+    /**
+    * @brief   Optionally return a PocoJsonArray instance.
+    *
+    * If the referenced PocoJson value is an array, this function will return
+    * a std::optional containing a PocoJsonArray instance referencing the
+    * array.
+    *
+    * Otherwise it will return an empty optional.
+    */
+    opt::optional<PocoJsonArray> getArrayOptional() const
+    {
+        if (m_value.type() == typeid(Poco::JSON::Array::Ptr)) {
+            return opt::make_optional(PocoJsonArray(m_value));
+        }
+
+        return opt::optional<PocoJsonArray>();
+    }
+
+    /**
+    * @brief   Retrieve the number of elements in the array
+    *
+    * If the referenced PocoJson value is an array, this function will
+    * retrieve the number of elements in the array and store it in the output
+    * variable provided.
+    *
+    * @param   result  reference to size_t to set with result
+    *
+    * @returns true if the number of elements was retrieved, false otherwise.
+    */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_value.type() == typeid(Poco::JSON::Array::Ptr)) {
+            result = m_value.extract<Poco::JSON::Array::Ptr>()->size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getBool(bool &result) const
+    {
+        if (m_value.isBoolean()) {
+            result = m_value.convert<bool>();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getDouble(double &result) const
+    {
+        if (m_value.isNumeric() && !m_value.isInteger()) {
+            result = m_value.convert<double>();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getInteger(int64_t &result) const
+    {
+        if (m_value.isInteger()) {
+            result = m_value.convert<int>();
+            return true;
+        }
+        return false;
+    }
+
+    /**
+    * @brief   Optionally return a PocoJsonObject instance.
+    *
+    * If the referenced PocoJson value is an object, this function will return a
+    * std::optional containing a PocoJsonObject instance referencing the
+    * object.
+    *
+    * Otherwise it will return an empty optional.
+    */
+    opt::optional<PocoJsonObject> getObjectOptional() const
+    {
+        if (m_value.type() == typeid(Poco::JSON::Object::Ptr)) {
+            return opt::make_optional(PocoJsonObject(m_value));
+        }
+
+        return opt::optional<PocoJsonObject>();
+    }
+
+    /**
+    * @brief   Retrieve the number of members in the object
+    *
+    * If the referenced PocoJson value is an object, this function will
+    * retrieve the number of members in the object and store it in the output
+    * variable provided.
+    *
+    * @param   result  reference to size_t to set with result
+    *
+    * @returns true if the number of members was retrieved, false otherwise.
+    */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_value.type() == typeid(Poco::JSON::Object::Ptr)) {
+            result = m_value.extract<Poco::JSON::Object::Ptr>()->size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value.isString()) {
+            result = m_value.convert<std::string>();
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return true;
+    }
+
+    bool isArray() const
+    {
+        return m_value.type() == typeid(Poco::JSON::Array::Ptr);
+    }
+
+    bool isBool() const
+    {
+        return m_value.isBoolean();
+    }
+
+    bool isDouble() const
+    {
+        return m_value.isNumeric() && !m_value.isInteger();
+    }
+
+    bool isInteger() const
+    {
+        return !isBool() && m_value.isInteger();
+    }
+
+    bool isNull() const
+    {
+        return m_value.isEmpty();
+    }
+
+    bool isNumber() const
+    {
+        return m_value.isNumeric();
+    }
+
+    bool isObject() const
+    {
+        return m_value.type() == typeid(Poco::JSON::Object::Ptr);
+    }
+
+    bool isString() const
+    {
+        return m_value.isString();
+    }
+
+private:
+
+    /// Return an empty object
+    static Poco::Dynamic::Var emptyObject()
+    {
+        Poco::Dynamic::Var object = Poco::JSON::Object::Ptr();
+        return object;
+    }
+
+    /// Contained value
+    Poco::Dynamic::Var m_value;
+};
+
+/**
+* @brief   An implementation of the Adapter interface supporting PocoJson.
+*
+* This class is defined in terms of the BasicAdapter template class, which
+* helps to ensure that all of the Adapter implementations behave consistently.
+*
+* @see Adapter
+* @see BasicAdapter
+*/
+class PocoJsonAdapter :
+    public BasicAdapter<PocoJsonAdapter,
+    PocoJsonArray,
+    PocoJsonObjectMember,
+    PocoJsonObject,
+    PocoJsonValue>
+{
+public:
+    /// Construct a PocoJsonAdapter that contains an empty object
+    PocoJsonAdapter()
+        : BasicAdapter()
+    { }
+
+    /// Construct a PocoJsonAdapter containing a specific Poco Json object
+    PocoJsonAdapter(const Poco::Dynamic::Var &value)
+        : BasicAdapter(PocoJsonValue {value})
+    { }
+};
+
+/**
+* @brief   Class for iterating over values held in a JSON array.
+*
+* This class provides a JSON array iterator that dereferences as an instance of
+* PocoJsonAdapter representing a value stored in the array. It has been
+* implemented using the boost iterator_facade template.
+*
+* @see PocoJsonArray
+*/
+class PocoJsonArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = PocoJsonAdapter;
+    using difference_type = PocoJsonAdapter;
+    using pointer = PocoJsonAdapter*;
+    using reference = PocoJsonAdapter&;
+
+    /**
+    * @brief   Construct a new PocoJsonArrayValueIterator using an existing
+    *          PocoJson iterator.
+    *
+    * @param   itr  PocoJson iterator to store
+    */
+    PocoJsonArrayValueIterator(const Poco::JSON::Array::ConstIterator &itr)
+        : m_itr(itr)
+    { }
+
+    /// Returns a PocoJsonAdapter that contains the value of the current
+    /// element.
+    PocoJsonAdapter operator*() const
+    {
+        return PocoJsonAdapter(*m_itr);
+    }
+
+    DerefProxy<PocoJsonAdapter> operator->() const
+    {
+        return DerefProxy<PocoJsonAdapter>(**this);
+    }
+
+    /**
+    * @brief   Compare this iterator against another iterator.
+    *
+    * Note that this directly compares the iterators, not the underlying
+    * values, and assumes that two identical iterators will point to the same
+    * underlying object.
+    *
+    * @param   other  iterator to compare against
+    *
+    * @returns true   if the iterators are equal, false otherwise.
+    */
+    bool operator==(const PocoJsonArrayValueIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const PocoJsonArrayValueIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const PocoJsonArrayValueIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    PocoJsonArrayValueIterator operator++(int)
+    {
+        PocoJsonArrayValueIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const PocoJsonArrayValueIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        m_itr += n;
+    }
+
+private:
+    Poco::JSON::Array::ConstIterator m_itr;
+};
+
+
+/**
+* @brief   Class for iterating over the members belonging to a JSON object.
+*
+* This class provides a JSON object iterator that dereferences as an instance
+* of PocoJsonObjectMember representing one of the members of the object. It
+* has been implemented using the boost iterator_facade template.
+*
+* @see PocoJsonObject
+* @see PocoJsonObjectMember
+*/
+class PocoJsonObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = PocoJsonObjectMember;
+    using difference_type = PocoJsonObjectMember;
+    using pointer = PocoJsonObjectMember*;
+    using reference = PocoJsonObjectMember&;
+
+    /**
+    * @brief   Construct an iterator from a PocoJson iterator.
+    *
+    * @param   itr  PocoJson iterator to store
+    */
+    PocoJsonObjectMemberIterator(const Poco::JSON::Object::ConstIterator &itr)
+        : m_itr(itr)
+    { }
+
+    /**
+    * @brief   Returns a PocoJsonObjectMember that contains the key and value
+    *          belonging to the object member identified by the iterator.
+    */
+    PocoJsonObjectMember operator*() const
+    {
+        return PocoJsonObjectMember(m_itr->first, m_itr->second);
+    }
+
+    DerefProxy<PocoJsonObjectMember> operator->() const
+    {
+        return DerefProxy<PocoJsonObjectMember>(**this);
+    }
+
+    /**
+    * @brief   Compare this iterator with another iterator.
+    *
+    * Note that this directly compares the iterators, not the underlying
+    * values, and assumes that two identical iterators will point to the same
+    * underlying object.
+    *
+    * @param   other  Iterator to compare with
+    *
+    * @returns true if the underlying iterators are equal, false otherwise
+    */
+    bool operator==(const PocoJsonObjectMemberIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const PocoJsonObjectMemberIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const PocoJsonObjectMemberIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    PocoJsonObjectMemberIterator operator++(int)
+    {
+        PocoJsonObjectMemberIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const PocoJsonObjectMemberIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+private:
+
+    /// Iternal copy of the original PocoJson iterator
+    Poco::JSON::Object::ConstIterator m_itr;
+};
+
+/// Specialisation of the AdapterTraits template struct for PocoJsonAdapter.
+template<>
+struct AdapterTraits<valijson::adapters::PocoJsonAdapter>
+{
+    typedef Poco::Dynamic::Var DocumentType;
+
+    static std::string adapterName()
+    {
+        return "PocoJsonAdapter";
+    }
+};
+
+inline PocoJsonArrayValueIterator PocoJsonArray::begin() const
+{
+    return m_value.extract<Poco::JSON::Array::Ptr>()->begin();
+}
+
+inline PocoJsonArrayValueIterator PocoJsonArray::end() const
+{
+    return m_value.extract<Poco::JSON::Array::Ptr>()->end();
+}
+
+inline PocoJsonObjectMemberIterator PocoJsonObject::begin() const
+{
+    return m_value.extract<Poco::JSON::Object::Ptr>()->begin();
+}
+
+inline PocoJsonObjectMemberIterator PocoJsonObject::end() const
+{
+    return m_value.extract<Poco::JSON::Object::Ptr>()->end();
+}
+
+inline PocoJsonObjectMemberIterator PocoJsonObject::find(const std::string &propertyName) const
+{
+    auto& ptr = m_value.extract<Poco::JSON::Object::Ptr>();
+
+    auto it = std::find_if(ptr->begin(), ptr->end(), [&propertyName](const Poco::JSON::Object::ValueType& p) {
+        return p.first == propertyName;
+    });
+    return it;
+}
+
+inline bool PocoJsonFrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return PocoJsonAdapter(m_value).equalTo(other, strict);
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/property_tree_adapter.hpp b/subprojects/valijson/include/valijson/adapters/property_tree_adapter.hpp
new file mode 100644
index 000000000..425547fb6
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/property_tree_adapter.hpp
@@ -0,0 +1,753 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation for the Boost property tree library.
+ *
+ * Include this file in your program to enable support for boost property trees.
+ *
+ * This file defines the following classes (not in this order):
+ *  - PropertyTreeAdapter
+ *  - PropertyTreeArray
+ *  - PropertyTreeArrayValueIterator
+ *  - PropertyTreeFrozenValue
+ *  - PropertyTreeObject
+ *  - PropertyTreeObjectMember
+ *  - PropertyTreeObjectMemberIterator
+ *  - PropertyTreeValue
+ *
+ * Due to the dependencies that exist between these classes, the ordering of
+ * class declarations and definitions may be a bit confusing. The best place to
+ * start is PropertyTreeAdapter. This class definition is actually very small,
+ * since most of the functionality is inherited from the BasicAdapter class.
+ * Most of the classes in this file are provided as template arguments to the
+ * inherited BasicAdapter class.
+ */
+
+#pragma once
+
+#include <string>
+
+#include <boost/property_tree/ptree.hpp>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+
+namespace valijson {
+namespace adapters {
+
+class PropertyTreeAdapter;
+class PropertyTreeArrayValueIterator;
+class PropertyTreeObjectMemberIterator;
+
+typedef std::pair<std::string, PropertyTreeAdapter> PropertyTreeObjectMember;
+
+/**
+ * @brief   Light weight wrapper for a Boost property tree that contains
+ *          array-like data.
+ *
+ * This class is light weight wrapper for a Boost property tree. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to a Boost property
+ * tree that is assumed to contain unnamed key-value pairs. There is very little
+ * associated with copy construction and passing by value.
+ */
+class PropertyTreeArray
+{
+public:
+
+    typedef PropertyTreeArrayValueIterator const_iterator;
+    typedef PropertyTreeArrayValueIterator iterator;
+
+    /// Construct a PropertyTreeArray referencing an empty property tree
+    /// singleton.
+    PropertyTreeArray()
+      : m_array(emptyTree()) { }
+
+    /**
+     * @brief   Construct PropertyTreeArray referencing a specific Boost
+     *          property tree.
+     *
+     * @param   array   reference to a property tree containing an array
+     *
+     * It is assumed that this value contains array-like data, but this is not
+     * checked due to runtime cost.
+     */
+    explicit PropertyTreeArray(const boost::property_tree::ptree &array)
+      : m_array(array) { }
+
+    /// Return an iterator for the first element in the array.
+    PropertyTreeArrayValueIterator begin() const;
+
+    /// Return an iterator for one-past the last element of the array.
+    PropertyTreeArrayValueIterator end() const;
+
+    /// Return the number of elements in the array
+    size_t size() const
+    {
+        return m_array.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a property tree that looks like an
+     *          empty array.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const boost::property_tree::ptree & emptyTree()
+    {
+        static const boost::property_tree::ptree tree;
+        return tree;
+    }
+
+    /// Reference to the contained value
+    const boost::property_tree::ptree &m_array;
+};
+
+/**
+ * @brief  Light weight wrapper for a Boost property tree that contains
+ *         object-like data.
+ *
+ * This class is light weight wrapper for a Boost property tree. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * property tree value, assumed to be object-like, so there is very little
+ * overhead associated with copy construction and passing by value.
+ */
+class PropertyTreeObject
+{
+public:
+
+    typedef PropertyTreeObjectMemberIterator const_iterator;
+    typedef PropertyTreeObjectMemberIterator iterator;
+
+    /// Construct a PropertyTreeObject referencing an empty property tree.
+    PropertyTreeObject()
+      : m_object(emptyTree()) { }
+
+    /**
+     * @brief   Construct a PropertyTreeObject referencing a specific property
+     *          tree.
+     *
+     * @param   object  reference to a property tree containing an object
+     *
+     * Note that the value of the property tree is not checked, due to the
+     * runtime cost of doing so.
+     */
+    PropertyTreeObject(const boost::property_tree::ptree &object)
+      : m_object(object) { }
+
+    /**
+     * @brief   Return an iterator for this first object member
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying property tree
+     * implementation.
+     */
+    PropertyTreeObjectMemberIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for an invalid object member that indicates
+     *          the end of the collection.
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the pointer value returned by the underlying property tree
+     * implementation.
+     */
+    PropertyTreeObjectMemberIterator end() const;
+
+    /**
+     * @brief   Return an iterator for the object member with the specified
+     *          property name.
+     *
+     * If an object member with the specified name does not exist, the iterator
+     * returned will be the same as the iterator returned by the end() function.
+     *
+     * @param   property   property name to search for
+     */
+    PropertyTreeObjectMemberIterator find(const std::string &property) const;
+
+    /// Returns the number of members belonging to this object.
+    size_t size() const
+    {
+        return m_object.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to an empty property tree.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const boost::property_tree::ptree & emptyTree()
+    {
+        static const boost::property_tree::ptree tree;
+        return tree;
+    }
+
+    /// Reference to the contained object
+    const boost::property_tree::ptree &m_object;
+
+};
+
+/**
+ * @brief   Stores an independent copy of a Boost property tree.
+ *
+ * This class allows a property tree value to be stored independent of its
+ * original 'document'. Boost property trees make this easy to do, as they do
+ * not perform any custom memory management.
+ *
+ * @see FrozenValue
+ */
+class PropertyTreeFrozenValue: public FrozenValue
+{
+public:
+
+    /**
+     * @brief  Make a copy of a Boost property tree POD value
+     *
+     * @param  source  string containing the POD vlaue
+     */
+    explicit PropertyTreeFrozenValue(const boost::property_tree::ptree::data_type &source)
+      : m_value(source) { }
+
+    /**
+     * @brief  Make a copy of a Boost property tree object or array value
+     *
+     * @param  source  the property tree to be copied
+     */
+    explicit PropertyTreeFrozenValue(const boost::property_tree::ptree &source)
+      : m_value(source) { }
+
+    FrozenValue * clone() const override
+    {
+        return new PropertyTreeFrozenValue(m_value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+
+    /// Stored value
+    boost::property_tree::ptree m_value;
+};
+
+/**
+ * @brief   Light weight wrapper for a Boost property tree.
+ *
+ * This class is passed as an argument to the BasicAdapter template class,
+ * and is used to provide access to a Boost property tree value. This class
+ * is responsible for the mechanics of actually reading a property tree, whereas
+ * BasicAdapter class is responsible for the semantics of type comparisons
+ * and conversions.
+ *
+ * The functions that need to be provided by this class are defined implicitly
+ * by the implementation of the BasicAdapter template class.
+ *
+ * @see BasicAdapter
+ */
+class PropertyTreeValue
+{
+public:
+
+    /// Construct a wrapper for an empty property tree
+    PropertyTreeValue()
+      : m_object(emptyTree()) { }
+
+    /**
+     * @brief  Construct a PropertyTreeValue from a tree object
+     *
+     * This function will determine whether the tree object represents an array
+     * or an object by scanning the key names for any non-empty strings. In the
+     * case of an empty tree object, it is not possible to determine whether it
+     * is an array or an object, so it will be treated as an array by default.
+     * Empty arrays are considered equal to empty objects when compared using
+     * non-strict type comparison. Empty strings will also be stored as empty
+     * arrays.
+     *
+     * @param  tree  Tree object to be wrapped
+     */
+    PropertyTreeValue(const boost::property_tree::ptree &tree)
+    {
+        if (tree.data().empty()) {    // No string content
+            if (tree.empty()) {   // No children
+                m_array.emplace(tree);         // Treat as empty array
+            } else {
+                bool isArray = true;
+                for (const auto &node : tree) {
+                    if (!node.first.empty()) {
+                        isArray = false;
+                        break;
+                    }
+                }
+
+                if (isArray) {
+                    m_array.emplace(tree);
+                } else {
+                    m_object.emplace(tree);
+                }
+            }
+        } else {
+            m_value = tree.data();
+        }
+    }
+
+    /**
+     * @brief   Create a new PropertyTreeFrozenValue instance that contains the
+     *          value referenced by this PropertyTreeValue instance.
+     *
+     * @returns pointer to a new PropertyTreeFrozenValue instance, belonging to
+     *          the caller.
+     */
+    FrozenValue* freeze() const
+    {
+        if (m_array) {
+            return new PropertyTreeFrozenValue(*m_array);
+        } else if (m_object) {
+            return new PropertyTreeFrozenValue(*m_object);
+        } else {
+            return new PropertyTreeFrozenValue(*m_value);
+        }
+    }
+
+    /**
+     * @brief  Return an instance of PropertyTreeArrayAdapter.
+     *
+     * If the referenced property tree value is an array, this function will
+     * return a std::optional containing a PropertyTreeArray instance
+     * referencing the array.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<PropertyTreeArray> getArrayOptional() const
+    {
+        if (m_array) {
+            return opt::make_optional(PropertyTreeArray(*m_array));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of elements in the array
+     *
+     * If the referenced property tree value is an array, this function will
+     * retrieve the number of elements in the array and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of elements was retrieved, false otherwise.
+     */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_array) {
+            result = m_array->size();
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool getBool(bool &)
+    {
+        return false;
+    }
+
+    static bool getDouble(double &)
+    {
+        return false;
+    }
+
+    static bool getInteger(int64_t &)
+    {
+        return false;
+    }
+
+    /**
+     * @brief   Optionally return a PropertyTreeObject instance.
+     *
+     * If the referenced property tree is an object, this function will return a
+     * std::optional containing a PropertyTreeObject instance referencing the
+     * object.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<PropertyTreeObject> getObjectOptional() const
+    {
+        if (m_object) {
+            return opt::make_optional(PropertyTreeObject(*m_object));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of members in the object
+     *
+     * If the referenced property tree value is an object, this function will
+     * retrieve the number of members in the object and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of members was retrieved, false otherwise.
+     */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_object) {
+            result = m_object->size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value) {
+            result = *m_value;
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return false;
+    }
+
+    bool isArray() const
+    {
+        return static_cast<bool>(m_array);
+    }
+
+    static bool isBool()
+    {
+        return false;
+    }
+
+    static bool isDouble()
+    {
+        return false;
+    }
+
+    static bool isInteger()
+    {
+        return false;
+    }
+
+    static bool isNull()
+    {
+        return false;
+    }
+
+    static bool isNumber()
+    {
+        return false;
+    }
+
+    bool isObject() const
+    {
+        return static_cast<bool>(m_object);
+    }
+
+    bool isString() const
+    {
+        return static_cast<bool>(m_value);
+    }
+
+private:
+
+    static const boost::property_tree::ptree & emptyTree()
+    {
+        static const boost::property_tree::ptree tree;
+        return tree;
+    }
+
+    /// Reference used if the value is known to be an array
+    opt::optional<const boost::property_tree::ptree &> m_array;
+
+    /// Reference used if the value is known to be an object
+    opt::optional<const boost::property_tree::ptree &> m_object;
+
+    /// Reference used if the value is known to be a POD type
+    opt::optional<std::string> m_value;
+};
+
+/**
+ * @brief   An implementation of the Adapter interface supporting the Boost
+ *          property tree library.
+ *
+ * This class is defined in terms of the BasicAdapter template class, which
+ * helps to ensure that all of the Adapter implementations behave consistently.
+ *
+ * @see Adapter
+ * @see BasicAdapter
+ */
+class PropertyTreeAdapter:
+    public BasicAdapter<PropertyTreeAdapter,
+                        PropertyTreeArray,
+                        PropertyTreeObjectMember,
+                        PropertyTreeObject,
+                        PropertyTreeValue>
+{
+public:
+
+    /// Construct a PropertyTreeAdapter for an empty property tree
+    PropertyTreeAdapter()
+      : BasicAdapter() { }
+
+    /// Construct a PropertyTreeAdapter using a specific property tree
+    PropertyTreeAdapter(const boost::property_tree::ptree &value)
+      : BasicAdapter(value) { }
+};
+
+/**
+ * @brief   Class for iterating over values held in a JSON array.
+ *
+ * This class provides a JSON array iterator that dereferences as an instance of
+ * PropertyTreeAdapter representing a value stored in the array. It has been
+ * implemented using the boost iterator_facade template.
+ *
+ * @see PropertyTreeArray
+ */
+class PropertyTreeArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = PropertyTreeAdapter;
+    using difference_type = PropertyTreeAdapter;
+    using pointer = PropertyTreeAdapter*;
+    using reference = PropertyTreeAdapter&;
+
+    /**
+     * @brief   Construct a new PropertyTreeArrayValueIterator using an existing
+     *          property tree iterator.
+     *
+     * @param   itr  property tree iterator to store
+     */
+    PropertyTreeArrayValueIterator(
+        const boost::property_tree::ptree::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /// Returns a PropertyTreeAdapter that contains the value of the current
+    /// element.
+    PropertyTreeAdapter operator*() const
+    {
+        return PropertyTreeAdapter(m_itr->second);
+    }
+
+    DerefProxy<PropertyTreeAdapter> operator->() const
+    {
+        return DerefProxy<PropertyTreeAdapter>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator against another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   rhs  iterator to compare against
+     *
+     * @returns true if the iterators are equal, false otherwise.
+     */
+    bool operator==(const PropertyTreeArrayValueIterator &rhs) const
+    {
+        return m_itr == rhs.m_itr;
+    }
+
+    bool operator!=(const PropertyTreeArrayValueIterator &rhs) const
+    {
+        return !(m_itr == rhs.m_itr);
+    }
+
+    const PropertyTreeArrayValueIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    PropertyTreeArrayValueIterator operator++(int)
+    {
+        PropertyTreeArrayValueIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const PropertyTreeArrayValueIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        if (n > 0) {
+            while (n-- > 0) {
+                m_itr++;
+            }
+        } else {
+            while (n++ < 0) {
+                m_itr--;
+            }
+        }
+    }
+
+private:
+
+    boost::property_tree::ptree::const_iterator m_itr;
+};
+
+/**
+ * @brief   Class for iterating over the members belonging to a JSON object.
+ *
+ * This class provides a JSON object iterator that dereferences as an instance
+ * of PropertyTreeObjectMember representing one of the members of the object.
+ * It has been implemented using the boost iterator_facade template.
+ *
+ * @see PropertyTreeObject
+ * @see PropertyTreeObjectMember
+ */
+class PropertyTreeObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = PropertyTreeObjectMember;
+    using difference_type = PropertyTreeObjectMember;
+    using pointer = PropertyTreeObjectMember*;
+    using reference = PropertyTreeObjectMember&;
+
+    /**
+     * @brief   Construct an iterator from a PropertyTree iterator.
+     *
+     * @param   itr  PropertyTree iterator to store
+     */
+    PropertyTreeObjectMemberIterator(
+        boost::property_tree::ptree::const_assoc_iterator itr)
+      : m_itr(itr) { }
+
+    /**
+     * @brief   Returns a PropertyTreeObjectMember that contains the key and
+     *          value belonging to the object member identified by the iterator.
+     */
+    PropertyTreeObjectMember operator*() const
+    {
+        return PropertyTreeObjectMember(m_itr->first, m_itr->second);
+    }
+
+    DerefProxy<PropertyTreeObjectMember> operator->() const
+    {
+        return DerefProxy<PropertyTreeObjectMember>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator with another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   rhs  Iterator to compare with
+     *
+     * @returns true if the underlying iterators are equal, false otherwise
+     */
+    bool operator==(const PropertyTreeObjectMemberIterator &rhs) const
+    {
+        return m_itr == rhs.m_itr;
+    }
+
+    bool operator!=(const PropertyTreeObjectMemberIterator &rhs) const
+    {
+        return !(m_itr == rhs.m_itr);
+    }
+
+    const PropertyTreeObjectMemberIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    PropertyTreeObjectMemberIterator operator++(int)
+    {
+        PropertyTreeObjectMemberIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const PropertyTreeObjectMemberIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+private:
+
+    boost::property_tree::ptree::const_assoc_iterator m_itr;
+};
+
+/// Specialisation of the AdapterTraits template struct for PropertyTreeAdapter.
+template<>
+struct AdapterTraits<valijson::adapters::PropertyTreeAdapter>
+{
+    typedef boost::property_tree::ptree DocumentType;
+
+    static std::string adapterName()
+    {
+        return "PropertyTreeAdapter";
+    }
+};
+
+inline bool PropertyTreeFrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return PropertyTreeAdapter(m_value).equalTo(other, strict);
+}
+
+inline PropertyTreeArrayValueIterator PropertyTreeArray::begin() const
+{
+    return m_array.begin();
+}
+
+inline PropertyTreeArrayValueIterator PropertyTreeArray::end() const
+{
+    return m_array.end();
+}
+
+inline PropertyTreeObjectMemberIterator PropertyTreeObject::begin() const
+{
+    return m_object.ordered_begin();
+}
+
+inline PropertyTreeObjectMemberIterator PropertyTreeObject::end() const
+{
+    return m_object.not_found();
+}
+
+inline PropertyTreeObjectMemberIterator PropertyTreeObject::find(
+    const std::string &propertyName) const
+{
+    const boost::property_tree::ptree::const_assoc_iterator itr = m_object.find(propertyName);
+
+    if (itr != m_object.not_found()) {
+        return itr;
+    }
+
+    return m_object.not_found();
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/qtjson_adapter.hpp b/subprojects/valijson/include/valijson/adapters/qtjson_adapter.hpp
new file mode 100644
index 000000000..2307fb5c3
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/qtjson_adapter.hpp
@@ -0,0 +1,722 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation for the QtJson parser library.
+ *
+ * Include this file in your program to enable support for QtJson.
+ *
+ * This file defines the following classes (not in this order):
+ *  - QtJsonAdapter
+ *  - QtJsonArray
+ *  - QtJsonArrayValueIterator
+ *  - QtJsonFrozenValue
+ *  - QtJsonObject
+ *  - QtJsonObjectMember
+ *  - QtJsonObjectMemberIterator
+ *  - QtJsonValue
+ *
+ * Due to the dependencies that exist between these classes, the ordering of
+ * class declarations and definitions may be a bit confusing. The best place to
+ * start is QtJsonAdapter. This class definition is actually very small,
+ * since most of the functionality is inherited from the BasicAdapter class.
+ * Most of the classes in this file are provided as template arguments to the
+ * inherited BasicAdapter class.
+ */
+
+#pragma once
+
+#include <string>
+#include <utility>
+
+#include <QJsonObject>
+#include <QJsonValue>
+#include <QJsonArray>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+class QtJsonAdapter;
+class QtJsonArrayValueIterator;
+class QtJsonObjectMemberIterator;
+
+typedef std::pair<std::string, QtJsonAdapter> QtJsonObjectMember;
+
+/**
+ * @brief  Light weight wrapper for a QtJson array value.
+ *
+ * This class is light weight wrapper for a QtJson array. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * QtJson value, assumed to be an array, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class QtJsonArray
+{
+public:
+
+    typedef QtJsonArrayValueIterator const_iterator;
+    typedef QtJsonArrayValueIterator iterator;
+
+    /// Construct a QtJsonArray referencing an empty array.
+    QtJsonArray()
+      : m_value(emptyArray())
+    {
+    }
+
+    /**
+     * @brief   Construct a QtJsonArray referencing a specific QtJson
+     *          value.
+     *
+     * @param   value   reference to a QtJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an array.
+     */
+    explicit QtJsonArray(const QJsonValue &value)
+      : m_value(value.toArray())
+    {
+        if (!value.isArray()) {
+            throwRuntimeError("Value is not an array.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for the first element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying QtJson implementation.
+     */
+    QtJsonArrayValueIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for one-past the last element of the array.
+     *
+     * The iterator return by this function is effectively the iterator
+     * returned by the underlying QtJson implementation.
+     */
+    QtJsonArrayValueIterator end() const;
+
+    /// Return the number of elements in the array
+    size_t size() const
+    {
+        return m_value.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a QtJson value that is an empty array.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static QJsonArray emptyArray()
+    {
+        static const QJsonArray array;
+        return array;
+    }
+
+    /// Reference to the contained value
+    const QJsonArray m_value;
+};
+
+/**
+ * @brief  Light weight wrapper for a QtJson object.
+ *
+ * This class is light weight wrapper for a QtJson object. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * QtJson value, assumed to be an object, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+class QtJsonObject
+{
+public:
+
+    typedef QtJsonObjectMemberIterator const_iterator;
+    typedef QtJsonObjectMemberIterator iterator;
+
+    /// Construct a QtJsonObject referencing an empty object singleton.
+    QtJsonObject()
+      : m_value(emptyObject())
+    {
+    }
+
+    /**
+     * @brief   Construct a QtJsonObject referencing a specific QtJson
+     *          value.
+     *
+     * @param   value  reference to a QtJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an object.
+     */
+    QtJsonObject(const QJsonValue &value)
+      : m_value(value.toObject())
+    {
+        if (!value.isObject()) {
+            throwRuntimeError("Value is not an object.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for this first object member
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying QtJson implementation.
+     */
+    QtJsonObjectMemberIterator begin() const;
+
+    /**
+     * @brief   Return an iterator for an invalid object member that indicates
+     *          the end of the collection.
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the iterator value returned by the underlying QtJson implementation.
+     */
+    QtJsonObjectMemberIterator end() const;
+
+    /**
+     * @brief   Return an iterator for the object member with the specified
+     *          property name.
+     *
+     * If an object member with the specified name does not exist, the iterator
+     * returned will be the same as the iterator returned by the end() function.
+     *
+     * @param   propertyName  property name to search for
+     */
+    QtJsonObjectMemberIterator find(const std::string &propertyName) const;
+
+    /// Returns the number of members belonging to this object.
+    size_t size() const
+    {
+        return m_value.size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a QtJson value that is empty object.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const QJsonObject emptyObject()
+    {
+        static const QJsonObject object;
+        return object;
+    }
+
+    /// Reference to the contained object
+    const QJsonObject m_value;
+};
+
+/**
+ * @brief   Stores an independent copy of a QtJson value.
+ *
+ * This class allows a QtJson value to be stored independent of its original
+ * document. QtJson makes this easy to do, as it does not perform any
+ * custom memory management.
+ *
+ * @see FrozenValue
+ */
+class QtJsonFrozenValue: public FrozenValue
+{
+public:
+
+    /**
+     * @brief  Make a copy of a QtJson value
+     *
+     * @param  source  the QtJson value to be copied
+     */
+    explicit QtJsonFrozenValue(QJsonValue source)
+      : m_value(std::move(source)) { }
+
+    FrozenValue * clone() const override
+    {
+        return new QtJsonFrozenValue(m_value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+
+    /// Stored QtJson value
+    QJsonValue m_value;
+};
+
+/**
+ * @brief   Light weight wrapper for a QtJson value.
+ *
+ * This class is passed as an argument to the BasicAdapter template class,
+ * and is used to provide access to a QtJson value. This class is responsible
+ * for the mechanics of actually reading a QtJson value, whereas the
+ * BasicAdapter class is responsible for the semantics of type comparisons
+ * and conversions.
+ *
+ * The functions that need to be provided by this class are defined implicitly
+ * by the implementation of the BasicAdapter template class.
+ *
+ * @see BasicAdapter
+ */
+class QtJsonValue
+{
+public:
+
+    /// Construct a wrapper for the empty object singleton
+    QtJsonValue()
+      : m_value(emptyObject()) { }
+
+    /// Construct a wrapper for a specific QtJson value
+    QtJsonValue(QJsonValue value)
+      : m_value(std::move(value)) { }
+
+    /**
+     * @brief   Create a new QtJsonFrozenValue instance that contains the
+     *          value referenced by this QtJsonValue instance.
+     *
+     * @returns pointer to a new QtJsonFrozenValue instance, belonging to the
+     *          caller.
+     */
+    FrozenValue * freeze() const
+    {
+        return new QtJsonFrozenValue(m_value);
+    }
+
+    /**
+     * @brief   Optionally return a QtJsonArray instance.
+     *
+     * If the referenced QtJson value is an array, this function will return
+     * a std::optional containing a QtJsonArray instance referencing the
+     * array.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<QtJsonArray> getArrayOptional() const
+    {
+        if (m_value.isArray()) {
+            return opt::make_optional(QtJsonArray(m_value));
+        }
+
+        return opt::optional<QtJsonArray>();
+    }
+
+    /**
+     * @brief   Retrieve the number of elements in the array
+     *
+     * If the referenced QtJson value is an array, this function will
+     * retrieve the number of elements in the array and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of elements was retrieved, false otherwise.
+     */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_value.isArray()) {
+            const QJsonArray array = m_value.toArray();
+            result = array.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getBool(bool &result) const
+    {
+        if (m_value.isBool()) {
+            result = m_value.toBool();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getDouble(double &result) const
+    {
+        if (m_value.isDouble()) {
+            result = m_value.toDouble();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getInteger(int64_t &result) const
+    {
+        if (m_value.isDouble()) {
+            result = m_value.toInt();
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Optionally return a QtJsonObject instance.
+     *
+     * If the referenced QtJson value is an object, this function will return a
+     * std::optional containing a QtJsonObject instance referencing the
+     * object.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<QtJsonObject> getObjectOptional() const
+    {
+        if (m_value.isObject()) {
+            return opt::make_optional(QtJsonObject(m_value));
+        }
+
+        return opt::optional<QtJsonObject>();
+    }
+
+    /**
+     * @brief   Retrieve the number of members in the object
+     *
+     * If the referenced QtJson value is an object, this function will
+     * retrieve the number of members in the object and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of members was retrieved, false otherwise.
+     */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_value.isObject()) {
+            const QJsonObject &object = m_value.toObject();
+            result = object.size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value.isString()) {
+            result = m_value.toString().toStdString();
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return true;
+    }
+
+    bool isArray() const
+    {
+        return m_value.isArray();
+    }
+
+    bool isBool() const
+    {
+        return m_value.isBool();
+    }
+
+    bool isDouble() const
+    {
+        return m_value.isDouble();
+    }
+
+    bool isInteger() const
+    {
+        //toInt returns the default value (0, 1) if the value is not a whole number
+        return m_value.isDouble() && (m_value.toInt(0) == m_value.toInt(1));
+    }
+
+    bool isNull() const
+    {
+        return m_value.isNull();
+    }
+
+    bool isNumber() const
+    {
+        return m_value.isDouble();
+    }
+
+    bool isObject() const
+    {
+        return m_value.isObject();
+    }
+
+    bool isString() const
+    {
+        return m_value.isString();
+    }
+
+private:
+
+    /// Return a reference to an empty object singleton
+    static QJsonValue emptyObject()
+    {
+        static const QJsonValue object;
+        return object;
+    }
+
+    /// Reference to the contained QtJson value.
+    const QJsonValue m_value;
+};
+
+/**
+ * @brief   An implementation of the Adapter interface supporting QtJson.
+ *
+ * This class is defined in terms of the BasicAdapter template class, which
+ * helps to ensure that all of the Adapter implementations behave consistently.
+ *
+ * @see Adapter
+ * @see BasicAdapter
+ */
+class QtJsonAdapter:
+    public BasicAdapter<QtJsonAdapter,
+                        QtJsonArray,
+                        QtJsonObjectMember,
+                        QtJsonObject,
+                        QtJsonValue>
+{
+public:
+
+    /// Construct a QtJsonAdapter that contains an empty object
+    QtJsonAdapter()
+      : BasicAdapter() { }
+
+    /// Construct a QtJsonAdapter containing a specific QtJson value
+    QtJsonAdapter(const QJsonValue &value)
+      : BasicAdapter(value) { }
+};
+
+/**
+ * @brief   Class for iterating over values held in a JSON array.
+ *
+ * This class provides a JSON array iterator that dereferences as an instance of
+ * QtJsonAdapter representing a value stored in the array.
+ *
+ * @see QtJsonArray
+ */
+class QtJsonArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = QtJsonAdapter;
+    using difference_type = QtJsonAdapter;
+    using pointer = QtJsonAdapter*;
+    using reference = QtJsonAdapter&;
+
+    /**
+     * @brief   Construct a new QtJsonArrayValueIterator using an existing
+     *          QtJson iterator.
+     *
+     * @param   itr  QtJson iterator to store
+     */
+    QtJsonArrayValueIterator(const QJsonArray::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /// Returns a QtJsonAdapter that contains the value of the current
+    /// element.
+    QtJsonAdapter operator*() const
+    {
+        return QtJsonAdapter(*m_itr);
+    }
+
+    DerefProxy<QtJsonAdapter> operator->() const
+    {
+        return DerefProxy<QtJsonAdapter>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator against another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  iterator to compare against
+     *
+     * @returns true   if the iterators are equal, false otherwise.
+     */
+    bool operator==(const QtJsonArrayValueIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const QtJsonArrayValueIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const QtJsonArrayValueIterator& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    QtJsonArrayValueIterator operator++(int)
+    {
+        QtJsonArrayValueIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const QtJsonArrayValueIterator& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        m_itr += n;
+    }
+
+private:
+
+    QJsonArray::const_iterator m_itr;
+};
+
+/**
+ * @brief   Class for iterating over the members belonging to a JSON object.
+ *
+ * This class provides a JSON object iterator that dereferences as an instance
+ * of QtJsonObjectMember representing one of the members of the object. It
+ * has been implemented using the boost iterator_facade template.
+ *
+ * @see QtJsonObject
+ * @see QtJsonObjectMember
+ */
+class QtJsonObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = QtJsonObjectMember;
+    using difference_type = QtJsonObjectMember;
+    using pointer = QtJsonObjectMember*;
+    using reference = QtJsonObjectMember&;
+
+    /**
+     * @brief   Construct an iterator from a QtJson iterator.
+     *
+     * @param   itr  QtJson iterator to store
+     */
+    QtJsonObjectMemberIterator(const QJsonObject::const_iterator &itr)
+      : m_itr(itr) { }
+
+    /**
+     * @brief   Returns a QtJsonObjectMember that contains the key and value
+     *          belonging to the object member identified by the iterator.
+     */
+    QtJsonObjectMember operator*() const
+    {
+        std::string key = m_itr.key().toStdString();
+        return QtJsonObjectMember(key, m_itr.value());
+    }
+
+    DerefProxy<QtJsonObjectMember> operator->() const
+    {
+        return DerefProxy<QtJsonObjectMember>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator with another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  Iterator to compare with
+     *
+     * @returns true if the underlying iterators are equal, false otherwise
+     */
+    bool operator==(const QtJsonObjectMemberIterator &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const QtJsonObjectMemberIterator &other) const
+    {
+        return !(m_itr == other.m_itr);
+    }
+
+    const QtJsonObjectMemberIterator& operator++()
+    {
+        m_itr++;
+        return *this;
+    }
+
+    QtJsonObjectMemberIterator operator++(int)
+    {
+        QtJsonObjectMemberIterator iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    const QtJsonObjectMemberIterator& operator--(int)
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+private:
+
+    /// Iternal copy of the original QtJson iterator
+    QJsonObject::const_iterator m_itr;
+};
+
+/// Specialisation of the AdapterTraits template struct for QtJsonAdapter.
+template<>
+struct AdapterTraits<valijson::adapters::QtJsonAdapter>
+{
+    typedef QJsonValue DocumentType;
+
+    static std::string adapterName()
+    {
+        return "QtJsonAdapter";
+    }
+};
+
+inline bool QtJsonFrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return QtJsonAdapter(m_value).equalTo(other, strict);
+}
+
+inline QtJsonArrayValueIterator QtJsonArray::begin() const
+{
+    return m_value.begin();
+}
+
+inline QtJsonArrayValueIterator QtJsonArray::end() const
+{
+    return m_value.end();
+}
+
+inline QtJsonObjectMemberIterator QtJsonObject::begin() const
+{
+    return m_value.begin();
+}
+
+inline QtJsonObjectMemberIterator QtJsonObject::end() const
+{
+    return m_value.end();
+}
+
+inline QtJsonObjectMemberIterator QtJsonObject::find(
+    const std::string &propertyName) const
+{
+    return m_value.find(QString::fromStdString(propertyName));
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/rapidjson_adapter.hpp b/subprojects/valijson/include/valijson/adapters/rapidjson_adapter.hpp
new file mode 100644
index 000000000..c9ec75dcc
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/rapidjson_adapter.hpp
@@ -0,0 +1,937 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation for the RapidJson parser library.
+ *
+ * Include this file in your program to enable support for RapidJson.
+ *
+ * This file defines the following template classes (not in this order):
+ *  - GenericRapidJsonAdapter
+ *  - GenericRapidJsonArray
+ *  - GenericRapidJsonArrayValueIterator
+ *  - GenericRapidJsonFrozenValue
+ *  - GenericRapidJsonObject
+ *  - GenericRapidJsonObjectMember
+ *  - GenericRapidJsonObjectMemberIterator
+ *  - GenericRapidJsonValue
+ *
+ * All of these classes share a template argument called 'ValueType', which can
+ * be used to choose the underlying the RapidJson value type that is used. This
+ * allows different RapidJson encodings and allocators to be used.
+ *
+ * This file also defines the following typedefs, which use RapidJson's default
+ * ValueType:
+ *  - RapidJsonAdapter
+ *  - RapidJsonArray
+ *  - RapidJsonArrayValueIterator
+ *  - RapidJsonFrozenValue
+ *  - RapidJsonObject
+ *  - RapidJsonObjectMember
+ *  - RapidJsonObjectMemberIterator
+ *  - RapidJsonValue
+ *
+ * Due to the dependencies that exist between these classes, the ordering of
+ * class declarations and definitions may be a bit confusing. The best place to
+ * start is RapidJsonAdapter. This class definition is actually very small,
+ * since most of the functionality is inherited from the BasicAdapter class.
+ * Most of the classes in this file are provided as template arguments to the
+ * inherited BasicAdapter class.
+ */
+
+#pragma once
+
+#include <string>
+#include <iterator>
+
+#ifdef VALIJSON_USE_EXCEPTIONS
+    #ifdef RAPIDJSON_ASSERT
+        #warning "RAPIDJSON_ASSERT already defined."
+        #warning "Please include valijson/adapters/rapidjson_adapter.hpp before any RapidJSON headers."
+    #else
+        template<typename T>
+        T rapidjson_assert(T t, const std::string& file, const int line) {
+          if (t) {
+            return t;
+          }
+
+          throw std::runtime_error("assertion failed; file: " + file + "; line: " + std::to_string(line));
+        }
+
+        #define RAPIDJSON_ASSERT(x) rapidjson_assert(x, __FILE__, __LINE__)
+    #endif
+#endif
+
+#include <rapidjson/document.h>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+template<class ValueType = rapidjson::Value>
+class GenericRapidJsonAdapter;
+
+template<class ValueType = rapidjson::Value>
+class GenericRapidJsonArrayValueIterator;
+
+template<class ValueType = rapidjson::Value>
+class GenericRapidJsonObjectMemberIterator;
+
+/// Container for a property name and an associated RapidJson value
+template<class ValueType = rapidjson::Value>
+class GenericRapidJsonObjectMember :
+        public std::pair<std::string, GenericRapidJsonAdapter<ValueType>>
+{
+private:
+    typedef std::pair<std::string, GenericRapidJsonAdapter<ValueType>> Super;
+
+public:
+    GenericRapidJsonObjectMember(
+            const std::string &name,
+            const GenericRapidJsonAdapter<ValueType> &value)
+      : Super(name, value) { }
+};
+
+/**
+ * @brief   Light weight wrapper for a RapidJson array value.
+ *
+ * This class is light weight wrapper for a RapidJson array. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to an underlying
+ * RapidJson value, assumed to be an array, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+template<class ValueType = rapidjson::Value>
+class GenericRapidJsonArray
+{
+public:
+
+    typedef GenericRapidJsonArrayValueIterator<ValueType> const_iterator;
+    typedef GenericRapidJsonArrayValueIterator<ValueType> iterator;
+
+    /// Construct a RapidJsonArray referencing an empty array singleton.
+    GenericRapidJsonArray()
+      : m_value(emptyArray()) { }
+
+    /**
+     * @brief   Construct a RapidJsonArray referencing a specific RapidJson
+     *          value.
+     *
+     * @param   value   reference to a RapidJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an array.
+     */
+    GenericRapidJsonArray(const ValueType &value)
+      : m_value(value)
+    {
+        if (!value.IsArray()) {
+            throwRuntimeError("Value is not an array.");
+        }
+    }
+
+    /// Return an iterator for the first element in the array.
+    iterator begin() const;
+
+    /// Return an iterator for one-past the last element of the array.
+    iterator end() const;
+
+    /// Return the number of elements in the array
+    size_t size() const
+    {
+        return m_value.Size();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a RapidJson value that is an empty array.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const ValueType & emptyArray()
+    {
+        static const ValueType array(rapidjson::kArrayType);
+        return array;
+    }
+
+    /// Reference to the contained value
+    const ValueType &m_value;
+};
+
+/**
+ * @brief  Light weight wrapper for a RapidJson object.
+ *
+ * This class is light weight wrapper for a RapidJson object. It provides a
+ * minimum set of container functions and typedefs that allow it to be used as
+ * an iterable container.
+ *
+ * An instance of this class contains a single reference to the underlying
+ * RapidJson value, assumed to be an object, so there is very little overhead
+ * associated with copy construction and passing by value.
+ */
+template <class ValueType = rapidjson::Value>
+class GenericRapidJsonObject
+{
+public:
+
+    typedef GenericRapidJsonObjectMemberIterator<ValueType> const_iterator;
+    typedef GenericRapidJsonObjectMemberIterator<ValueType> iterator;
+
+    /// Construct a GenericRapidJsonObject referencing an empty object singleton.
+    GenericRapidJsonObject()
+      : m_value(emptyObject()) { }
+
+    /**
+     * @brief   Construct a GenericRapidJsonObject referencing a specific
+     *          RapidJson value.
+     *
+     * @param   value  reference to a RapidJson value
+     *
+     * Note that this constructor will throw an exception if the value is not
+     * an object.
+     */
+    GenericRapidJsonObject(const ValueType &value)
+      : m_value(value)
+    {
+        if (!value.IsObject()) {
+            throwRuntimeError("Value is not an object.");
+        }
+    }
+
+    /**
+     * @brief   Return an iterator for this first object member
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the pointer value returned by the underlying RapidJson implementation.
+     */
+    iterator begin() const;
+
+    /**
+     * @brief   Return an iterator for an invalid object member that indicates
+     *          the end of the collection.
+     *
+     * The iterator return by this function is effectively a wrapper around
+     * the pointer value returned by the underlying RapidJson implementation.
+     */
+    iterator end() const;
+
+    /**
+     * @brief   Return an iterator for the object member with the specified
+     *          property name.
+     *
+     * If an object member with the specified name does not exist, the iterator
+     * returned will be the same as the iterator returned by the end() function.
+     *
+     * @param   property   property name to search for
+     */
+    iterator find(const std::string &property) const;
+
+    /// Returns the number of members belonging to this object.
+    size_t size() const
+    {
+        return m_value.MemberEnd() - m_value.MemberBegin();
+    }
+
+private:
+
+    /**
+     * @brief   Return a reference to a RapidJson value that is empty object.
+     *
+     * Note that the value returned by this function is a singleton.
+     */
+    static const ValueType & emptyObject()
+    {
+        static ValueType object(rapidjson::kObjectType);
+        return object;
+    }
+
+    /// Reference to the contained object
+    const ValueType &m_value;
+};
+
+/**
+ * @brief   Stores an independent copy of a RapidJson value.
+ *
+ * This class allows a RapidJson value to be stored independent of its original
+ * document. RapidJson makes this a bit harder than usual, because RapidJson
+ * values are associated with a custom memory allocator. As such, RapidJson
+ * values have to be copied recursively, referencing a custom allocator held
+ * by this class.
+ *
+ * @see FrozenValue
+ */
+template<class ValueType = rapidjson::Value>
+class GenericRapidJsonFrozenValue: public FrozenValue
+{
+public:
+
+    explicit GenericRapidJsonFrozenValue(const char *str)
+    {
+        m_value.SetString(str, m_allocator);
+    }
+
+    explicit GenericRapidJsonFrozenValue(const std::string &str)
+    {
+        m_value.SetString(str.c_str(), (unsigned int)str.length(), m_allocator);
+    }
+
+    /**
+     * @brief   Make a copy of a RapidJson value
+     *
+     * @param   source  the RapidJson value to be copied
+     */
+    explicit GenericRapidJsonFrozenValue(const ValueType &source)
+    {
+        if (!copy(source, m_value, m_allocator)) {
+            throwRuntimeError("Failed to copy ValueType");
+        }
+    }
+
+    FrozenValue * clone() const override
+    {
+        return new GenericRapidJsonFrozenValue(m_value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+
+    /**
+     * @brief   Recursively copy a RapidJson value using a separate allocator
+     *
+     * @param   source      value to copy from
+     * @param   dest        value to copy into
+     * @param   allocator   reference to an allocator held by this class
+     *
+     * @tparam  Allocator   type of RapidJson Allocator to be used
+     *
+     * @returns true if copied successfully, false otherwise.
+     */
+    template<typename Allocator>
+    static bool copy(const ValueType &source,
+                     ValueType &dest,
+                     Allocator &allocator)
+    {
+        switch (source.GetType()) {
+        case rapidjson::kNullType:
+            dest.SetNull();
+            return true;
+        case rapidjson::kFalseType:
+            dest.SetBool(false);
+            return true;
+        case rapidjson::kTrueType:
+            dest.SetBool(true);
+            return true;
+        case rapidjson::kObjectType:
+            dest.SetObject();
+            for (typename ValueType::ConstMemberIterator itr = source.MemberBegin(); itr != source.MemberEnd(); ++itr) {
+                ValueType name(itr->name.GetString(), itr->name.GetStringLength(), allocator);
+                ValueType value;
+                copy(itr->value, value, allocator);
+                dest.AddMember(name, value, allocator);
+            }
+            return true;
+        case rapidjson::kArrayType:
+            dest.SetArray();
+            for (typename ValueType::ConstValueIterator itr = source.Begin(); itr != source.End(); ++itr) {
+                ValueType value;
+                copy(*itr, value, allocator);
+                dest.PushBack(value, allocator);
+            }
+            return true;
+        case rapidjson::kStringType:
+            dest.SetString(source.GetString(), source.GetStringLength(), allocator);
+            return true;
+        case rapidjson::kNumberType:
+            if (source.IsInt()) {
+                dest.SetInt(source.GetInt());
+            } else if (source.IsUint()) {
+                dest.SetUint(source.GetUint());
+            } else if (source.IsInt64()) {
+                dest.SetInt64(source.GetInt64());
+            } else if (source.IsUint64()) {
+                dest.SetUint64(source.GetUint64());
+            } else {
+                dest.SetDouble(source.GetDouble());
+            }
+            return true;
+        default:
+            break;
+        }
+
+        return false;
+    }
+
+    /// Local memory allocator for RapidJson value
+    typename ValueType::AllocatorType m_allocator;
+
+    /// Local RapidJson value
+    ValueType m_value;
+};
+
+/**
+ * @brief   Light weight wrapper for a RapidJson value.
+ *
+ * This class is passed as an argument to the BasicAdapter template class,
+ * and is used to provide access to a RapidJson value. This class is responsible
+ * for the mechanics of actually reading a RapidJson value, whereas the
+ * BasicAdapter class is responsible for the semantics of type comparisons
+ * and conversions.
+ *
+ * The functions that need to be provided by this class are defined implicitly
+ * by the implementation of the BasicAdapter template class.
+ *
+ * @see BasicAdapter
+ */
+template<class ValueType = rapidjson::Value>
+class GenericRapidJsonValue
+{
+public:
+    /// Construct a wrapper for the empty object singleton
+    GenericRapidJsonValue()
+      : m_value(emptyObject()) { }
+
+    /// Construct a wrapper for a specific RapidJson value
+    GenericRapidJsonValue(const ValueType &value)
+      : m_value(value) { }
+
+    /**
+     * @brief   Create a new GenericRapidJsonFrozenValue instance that contains
+     *          the value referenced by this GenericRapidJsonValue instance.
+     *
+     * @returns pointer to a new GenericRapidJsonFrozenValue instance, belonging
+     *          to the caller.
+     */
+    FrozenValue * freeze() const
+    {
+        return new GenericRapidJsonFrozenValue<ValueType>(m_value);
+    }
+
+    /**
+     * @brief   Optionally return a GenericRapidJsonArray instance.
+     *
+     * If the referenced RapidJson value is an array, this function will return
+     * a std::optional containing a GenericRapidJsonArray instance referencing
+     * the array.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<GenericRapidJsonArray<ValueType>> getArrayOptional() const
+    {
+        if (m_value.IsArray()) {
+            return opt::make_optional(GenericRapidJsonArray<ValueType>(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of elements in the array
+     *
+     * If the referenced RapidJson value is an array, this function will
+     * retrieve the number of elements in the array and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of elements was retrieved, false otherwise.
+     */
+    bool getArraySize(size_t &result) const
+    {
+        if (m_value.IsArray()) {
+            result = m_value.Size();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getBool(bool &result) const
+    {
+        if (m_value.IsBool()) {
+            result = m_value.GetBool();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getDouble(double &result) const
+    {
+        if (m_value.IsDouble()) {
+            result = m_value.GetDouble();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getInteger(int64_t &result) const
+    {
+        if (m_value.IsInt()) {
+            result = m_value.GetInt();
+            return true;
+        } else if (m_value.IsInt64()) {
+            result = m_value.GetInt64();
+            return true;
+        } else if (m_value.IsUint()) {
+            result = static_cast<int64_t>(m_value.GetUint());
+            return true;
+        } else if (m_value.IsUint64()) {
+            result = static_cast<int64_t>(m_value.GetUint64());
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Optionally return a GenericRapidJsonObject instance.
+     *
+     * If the referenced RapidJson value is an object, this function will return
+     * a std::optional containing a GenericRapidJsonObject instance
+     * referencing the object.
+     *
+     * Otherwise it will return an empty optional.
+     */
+    opt::optional<GenericRapidJsonObject<ValueType>> getObjectOptional() const
+    {
+        if (m_value.IsObject()) {
+            return opt::make_optional(GenericRapidJsonObject<ValueType>(m_value));
+        }
+
+        return {};
+    }
+
+    /**
+     * @brief   Retrieve the number of members in the object
+     *
+     * If the referenced RapidJson value is an object, this function will
+     * retrieve the number of members in the object and store it in the output
+     * variable provided.
+     *
+     * @param   result  reference to size_t to set with result
+     *
+     * @returns true if the number of members was retrieved, false otherwise.
+     */
+    bool getObjectSize(size_t &result) const
+    {
+        if (m_value.IsObject()) {
+            result = m_value.MemberEnd() - m_value.MemberBegin();
+            return true;
+        }
+
+        return false;
+    }
+
+    bool getString(std::string &result) const
+    {
+        if (m_value.IsString()) {
+            result.assign(m_value.GetString(), m_value.GetStringLength());
+            return true;
+        }
+
+        return false;
+    }
+
+    static bool hasStrictTypes()
+    {
+        return true;
+    }
+
+    bool isArray() const
+    {
+        return m_value.IsArray();
+    }
+
+    bool isBool() const
+    {
+        return m_value.IsBool();
+    }
+
+    bool isDouble() const
+    {
+        return m_value.IsDouble();
+    }
+
+    bool isInteger() const
+    {
+        return m_value.IsInt() || m_value.IsInt64() || m_value.IsUint() || m_value.IsUint64();
+    }
+
+    bool isNull() const
+    {
+        return m_value.IsNull();
+    }
+
+    bool isNumber() const
+    {
+        return m_value.IsNumber();
+    }
+
+    bool isObject() const
+    {
+        return m_value.IsObject();
+    }
+
+    bool isString() const
+    {
+        return m_value.IsString();
+    }
+
+private:
+
+    /// Return a reference to an empty object singleton
+    static const ValueType & emptyObject()
+    {
+        static const ValueType object(rapidjson::kObjectType);
+        return object;
+    }
+
+    /// Reference to the contained RapidJson value.
+    const ValueType &m_value;
+};
+
+/**
+ * @brief   An implementation of the Adapter interface supporting RapidJson.
+ *
+ * This class is defined in terms of the BasicAdapter template class, which
+ * helps to ensure that all of the Adapter implementations behave consistently.
+ *
+ * @see Adapter
+ * @see BasicAdapter
+ */
+template<class ValueType>
+class GenericRapidJsonAdapter:
+    public BasicAdapter<GenericRapidJsonAdapter<ValueType>,
+                        GenericRapidJsonArray<ValueType>,
+                        GenericRapidJsonObjectMember<ValueType>,
+                        GenericRapidJsonObject<ValueType>,
+                        GenericRapidJsonValue<ValueType>>
+{
+public:
+
+    /// Construct a RapidJsonAdapter that contains an empty object
+    GenericRapidJsonAdapter()
+      : BasicAdapter<GenericRapidJsonAdapter<ValueType>,
+                        GenericRapidJsonArray<ValueType>,
+                        GenericRapidJsonObjectMember<ValueType>,
+                        GenericRapidJsonObject<ValueType>,
+                        GenericRapidJsonValue<ValueType>>() { }
+
+    /// Construct a RapidJsonAdapter containing a specific RapidJson value
+    GenericRapidJsonAdapter(const ValueType &value)
+      : BasicAdapter<GenericRapidJsonAdapter<ValueType>,
+                        GenericRapidJsonArray<ValueType>,
+                        GenericRapidJsonObjectMember<ValueType>,
+                        GenericRapidJsonObject<ValueType>,
+                        GenericRapidJsonValue<ValueType>>(value) { }
+};
+
+/**
+ * @brief   Class for iterating over values held in a JSON array.
+ *
+ * This class provides a JSON array iterator that dereferences as an instance of
+ * RapidJsonAdapter representing a value stored in the array.
+ *
+ * @see RapidJsonArray
+ */
+template<class ValueType>
+class GenericRapidJsonArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = GenericRapidJsonAdapter<ValueType>;
+    using difference_type = GenericRapidJsonAdapter<ValueType>;
+    using pointer = GenericRapidJsonAdapter<ValueType>*;
+    using reference = GenericRapidJsonAdapter<ValueType>&;
+
+    /**
+     * @brief   Construct a new GenericRapidJsonArrayValueIterator using an
+     *          existing RapidJson iterator.
+     *
+     * @param   itr  RapidJson iterator to store
+     */
+    GenericRapidJsonArrayValueIterator(
+        const typename ValueType::ConstValueIterator &itr)
+      : m_itr(itr) { }
+
+    /// Returns a GenericRapidJsonAdapter that contains the value of the current
+    /// element.
+    GenericRapidJsonAdapter<ValueType> operator*() const
+    {
+        return GenericRapidJsonAdapter<ValueType>(*m_itr);
+    }
+
+    /// Returns a proxy for the value of the current element
+    DerefProxy<GenericRapidJsonAdapter<ValueType>> operator->() const
+    {
+        return DerefProxy<GenericRapidJsonAdapter<ValueType>>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator against another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  iterator to compare against
+     *
+     * @returns true if the iterators are equal, false otherwise.
+     */
+    bool operator==(const GenericRapidJsonArrayValueIterator<ValueType> &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const GenericRapidJsonArrayValueIterator<ValueType>& other) const
+    {
+        return m_itr != other.m_itr;
+    }
+
+    GenericRapidJsonArrayValueIterator<ValueType>& operator++()
+    {
+        m_itr++;
+
+        return *this;
+    }
+
+    GenericRapidJsonArrayValueIterator<ValueType> operator++(int) {
+        GenericRapidJsonArrayValueIterator<ValueType> iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    GenericRapidJsonArrayValueIterator<ValueType>& operator--()
+    {
+        m_itr--;
+
+        return *this;
+    }
+
+    void advance(std::ptrdiff_t n)
+    {
+        m_itr += n;
+    }
+
+    std::ptrdiff_t difference(const GenericRapidJsonArrayValueIterator<ValueType> &other)
+    {
+        return std::distance(m_itr, other.itr);
+    }
+
+private:
+
+    typename ValueType::ConstValueIterator m_itr;
+};
+
+/**
+ * @brief   Class for iterating over the members belonging to a JSON object.
+ *
+ * This class provides a JSON object iterator that dereferences as an instance
+ * of GenericRapidJsonObjectMember representing one of the members of the
+ * object.
+ *
+ * @see GenericRapidJsonObject
+ * @see GenericRapidJsonObjectMember
+ */
+template<class ValueType>
+class GenericRapidJsonObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = GenericRapidJsonObjectMember<ValueType>;
+    using difference_type = GenericRapidJsonObjectMember<ValueType>;
+    using pointer = GenericRapidJsonObjectMember<ValueType>*;
+    using reference = GenericRapidJsonObjectMember<ValueType>&;
+
+    /**
+     * @brief   Construct an iterator from a RapidJson iterator.
+     *
+     * @param   itr  RapidJson iterator to store
+     */
+    GenericRapidJsonObjectMemberIterator(
+        const typename ValueType::ConstMemberIterator &itr)
+      : m_itr(itr) { }
+
+
+    /**
+     * @brief   Returns a GenericRapidJsonObjectMember that contains the key and
+     *          value belonging to the object member identified by the iterator.
+     */
+    GenericRapidJsonObjectMember<ValueType> operator*() const
+    {
+        return GenericRapidJsonObjectMember<ValueType>(
+            std::string(m_itr->name.GetString(), m_itr->name.GetStringLength()),
+            m_itr->value);
+    }
+
+    /// Returns a proxy for the value of the current element
+    DerefProxy<GenericRapidJsonObjectMember<ValueType>> operator->() const
+    {
+        return DerefProxy<GenericRapidJsonObjectMember<ValueType>>(**this);
+    }
+
+    /**
+     * @brief   Compare this iterator with another iterator.
+     *
+     * Note that this directly compares the iterators, not the underlying
+     * values, and assumes that two identical iterators will point to the same
+     * underlying object.
+     *
+     * @param   other  Iterator to compare with
+     *
+     * @returns true if the underlying iterators are equal, false otherwise
+     */
+    bool operator==(const GenericRapidJsonObjectMemberIterator<ValueType> &other) const
+    {
+        return m_itr == other.m_itr;
+    }
+
+    bool operator!=(const GenericRapidJsonObjectMemberIterator<ValueType> &other) const
+    {
+        return m_itr != other.m_itr;
+    }
+
+    GenericRapidJsonObjectMemberIterator<ValueType>& operator++()
+    {
+        m_itr++;
+        return *this;
+    }
+
+    GenericRapidJsonObjectMemberIterator<ValueType> operator++(int)
+    {
+        GenericRapidJsonObjectMemberIterator<ValueType> iterator_pre(m_itr);
+        ++(*this);
+        return iterator_pre;
+    }
+
+    GenericRapidJsonObjectMemberIterator<ValueType>& operator--()
+    {
+        m_itr--;
+        return *this;
+    }
+
+    std::ptrdiff_t difference(const GenericRapidJsonObjectMemberIterator &other)
+    {
+        return std::distance(m_itr, other.itr);
+    }
+
+private:
+
+    /// Iternal copy of the original RapidJson iterator
+    typename ValueType::ConstMemberIterator m_itr;
+};
+
+template<class ValueType>
+inline bool GenericRapidJsonFrozenValue<ValueType>::equalTo(const Adapter &other, bool strict) const
+{
+    return GenericRapidJsonAdapter<ValueType>(m_value).equalTo(other, strict);
+}
+
+template<class ValueType>
+inline typename GenericRapidJsonArray<ValueType>::iterator GenericRapidJsonArray<ValueType>::begin() const
+{
+    return m_value.Begin();
+}
+
+template<class ValueType>
+inline typename GenericRapidJsonArray<ValueType>::iterator GenericRapidJsonArray<ValueType>::end() const
+{
+    return m_value.End();
+}
+
+template<class ValueType>
+inline typename GenericRapidJsonObject<ValueType>::iterator GenericRapidJsonObject<ValueType>::begin() const
+{
+    return m_value.MemberBegin();
+}
+
+template<class ValueType>
+inline typename GenericRapidJsonObject<ValueType>::iterator GenericRapidJsonObject<ValueType>::end() const
+{
+    return m_value.MemberEnd();
+}
+
+template<class ValueType>
+inline typename GenericRapidJsonObject<ValueType>::iterator
+        GenericRapidJsonObject<ValueType>::find(const std::string &propertyName) const
+{
+    // Hack to support older versions of rapidjson where pointers are used as
+    // the built in iterator type. In those versions, the FindMember function
+    // would return a null pointer when the requested member could not be
+    // found. After calling FindMember on an empty object, we compare the
+    // result against what we would expect if a non-null-pointer iterator was
+    // returned.
+    const ValueType empty(rapidjson::kObjectType);
+    const typename ValueType::ConstMemberIterator maybeEnd = empty.FindMember("");
+    if (maybeEnd != empty.MemberBegin() + 1) {
+        // In addition to the pointer-based iterator issue, RapidJson's internal
+        // string comparison code seemed to rely on the query string being
+        // initialised to a length greater than or equal to that of the
+        // properties being compared. We get around this by implementing our
+        // own linear scan.
+        const size_t propertyNameLength = propertyName.length();
+        for (typename ValueType::ConstMemberIterator itr = m_value.MemberBegin(); itr != m_value.MemberEnd(); ++itr) {
+            const size_t memberNameLength = itr->name.GetStringLength();
+            if (memberNameLength == propertyNameLength &&
+                    strncmp(itr->name.GetString(), propertyName.c_str(), itr->name.GetStringLength()) == 0) {
+                return itr;
+            }
+        }
+
+        return m_value.MemberEnd();
+    }
+
+    return m_value.FindMember(propertyName.c_str());      // Times are good.
+}
+
+typedef GenericRapidJsonAdapter<> RapidJsonAdapter;
+typedef GenericRapidJsonArray<> RapidJsonArray;
+typedef GenericRapidJsonArrayValueIterator<> RapidJsonArrayValue;
+typedef GenericRapidJsonFrozenValue<> RapidJsonFrozenValue;
+typedef GenericRapidJsonObject<> RapidJsonObject;
+typedef GenericRapidJsonObjectMember<> RapidJsonObjectMember;
+typedef GenericRapidJsonObjectMemberIterator<> RapidJsonObjectMemberIterator;
+typedef GenericRapidJsonValue<> RapidJsonValue;
+
+/**
+ * @brief  Specialisation of the AdapterTraits template struct for a
+ *         RapidJsonAdapter that uses a pool allocator
+ */
+template<>
+struct AdapterTraits<valijson::adapters::RapidJsonAdapter>
+{
+    typedef rapidjson::Document DocumentType;
+
+    static std::string adapterName()
+    {
+        return "RapidJsonAdapter";
+    }
+};
+
+typedef rapidjson::GenericValue<rapidjson::UTF8<>, rapidjson::CrtAllocator> RapidJsonCrt;
+
+/**
+ * @brief  Specialisation of the AdapterTraits template struct for a
+ *         RapidJsonAdapter that uses the default CRT allocator
+ */
+template<>
+struct AdapterTraits<valijson::adapters::GenericRapidJsonAdapter<RapidJsonCrt>>
+{
+    typedef rapidjson::GenericDocument<rapidjson::UTF8<>, rapidjson::CrtAllocator> DocumentType;
+
+    static std::string adapterName()
+    {
+        return "GenericRapidJsonAdapter (using CrtAllocator)";
+    }
+};
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/adapters/std_string_adapter.hpp b/subprojects/valijson/include/valijson/adapters/std_string_adapter.hpp
new file mode 100644
index 000000000..2084024f2
--- /dev/null
+++ b/subprojects/valijson/include/valijson/adapters/std_string_adapter.hpp
@@ -0,0 +1,491 @@
+/**
+ * @file
+ *
+ * @brief   Adapter implementation that wraps a single std::string value
+ *
+ * This allows property names to be validated against a schema as though they are a generic JSON
+ * value, while allowing the rest of Valijson's API to expose property names as plain std::string
+ * values.
+ *
+ * This was added while implementing draft 7 support. This included support for a constraint
+ * called propertyNames, which can be used to ensure that the property names in an object
+ * validate against a subschema.
+ */
+
+#pragma once
+
+#include <string>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/adapters/basic_adapter.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace adapters {
+
+class StdStringAdapter;
+class StdStringArrayValueIterator;
+class StdStringObjectMemberIterator;
+
+typedef std::pair<std::string, StdStringAdapter> StdStringObjectMember;
+
+class StdStringArray
+{
+public:
+    typedef StdStringArrayValueIterator const_iterator;
+    typedef StdStringArrayValueIterator iterator;
+
+    StdStringArray() = default;
+
+    StdStringArrayValueIterator begin() const;
+
+    StdStringArrayValueIterator end() const;
+
+    static size_t size()
+    {
+        return 0;
+    }
+};
+
+class StdStringObject
+{
+public:
+    typedef StdStringObjectMemberIterator const_iterator;
+    typedef StdStringObjectMemberIterator iterator;
+
+    StdStringObject() = default;
+
+    StdStringObjectMemberIterator begin() const;
+
+    StdStringObjectMemberIterator end() const;
+
+    StdStringObjectMemberIterator find(const std::string &propertyName) const;
+
+    static size_t size()
+    {
+        return 0;
+    }
+};
+
+class StdStringFrozenValue: public FrozenValue
+{
+public:
+    explicit StdStringFrozenValue(std::string source)
+      : value(std::move(source)) { }
+
+    FrozenValue * clone() const override
+    {
+        return new StdStringFrozenValue(value);
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override;
+
+private:
+    std::string value;
+};
+
+class StdStringAdapter: public Adapter
+{
+public:
+    typedef StdStringArray Array;
+    typedef StdStringObject Object;
+    typedef StdStringObjectMember ObjectMember;
+
+    explicit StdStringAdapter(const std::string &value)
+      : m_value(value) { }
+
+    bool applyToArray(ArrayValueCallback) const override
+    {
+        return maybeArray();
+    }
+
+    bool applyToObject(ObjectMemberCallback) const override
+    {
+        return maybeObject();
+    }
+
+    StdStringArray asArray() const
+    {
+        if (maybeArray()) {
+            return {};
+        }
+
+        throwRuntimeError("String value cannot be cast to array");
+    }
+
+    bool asBool() const override
+    {
+        return true;
+    }
+
+    bool asBool(bool &result) const override
+    {
+        result = true;
+        return true;
+    }
+
+    double asDouble() const override
+    {
+        return 0;
+    }
+
+    bool asDouble(double &result) const override
+    {
+        result = 0;
+        return true;
+    }
+
+    int64_t asInteger() const override
+    {
+        return 0;
+    }
+
+    bool asInteger(int64_t &result) const override
+    {
+        result = 0;
+        return true;
+    };
+
+    StdStringObject asObject() const
+    {
+        if (maybeObject()) {
+            return {};
+        }
+
+        throwRuntimeError("String value cannot be cast to object");
+    }
+
+    std::string asString() const override
+    {
+        return m_value;
+    }
+
+    bool asString(std::string &result) const override
+    {
+        result = m_value;
+        return true;
+    }
+
+    bool equalTo(const Adapter &other, bool strict) const override
+    {
+        if (strict && !other.isString()) {
+            return false;
+        }
+
+        return m_value == other.asString();
+    }
+
+    FrozenValue* freeze() const override
+    {
+        return new StdStringFrozenValue(m_value);
+    }
+
+    static StdStringArray getArray()
+    {
+        throwNotSupported();
+    }
+
+    size_t getArraySize() const override
+    {
+        throwNotSupported();
+    }
+
+    bool getArraySize(size_t &) const override
+    {
+        throwNotSupported();
+    }
+
+    bool getBool() const override
+    {
+        throwNotSupported();
+    }
+
+    bool getBool(bool &) const override
+    {
+        throwNotSupported();
+    }
+
+    double getDouble() const override
+    {
+        throwNotSupported();
+    }
+
+    bool getDouble(double &) const override
+    {
+        throwNotSupported();
+    }
+
+    int64_t getInteger() const override
+    {
+        throwNotSupported();
+    }
+
+    bool getInteger(int64_t &) const override
+    {
+        throwNotSupported();
+    }
+
+    double getNumber() const override
+    {
+        throwNotSupported();
+    }
+
+    bool getNumber(double &) const override
+    {
+        throwNotSupported();
+    }
+
+    size_t getObjectSize() const override
+    {
+        throwNotSupported();
+    }
+
+    bool getObjectSize(size_t &) const override
+    {
+        throwNotSupported();
+    }
+
+    std::string getString() const override
+    {
+        return m_value;
+    }
+
+    bool getString(std::string &result) const override
+    {
+        result = m_value;
+        return true;
+    }
+
+    bool hasStrictTypes() const override
+    {
+        return true;
+    }
+
+    bool isArray() const override
+    {
+        return false;
+    }
+
+    bool isBool() const override
+    {
+        return false;
+    }
+
+    bool isDouble() const override
+    {
+        return false;
+    }
+
+    bool isInteger() const override
+    {
+        return false;
+    }
+
+    bool isNull() const override
+    {
+        return false;
+    }
+
+    bool isNumber() const override
+    {
+        return false;
+    }
+
+    bool isObject() const override
+    {
+        return false;
+    }
+
+    bool isString() const override
+    {
+        return true;
+    }
+
+    bool maybeArray() const override
+    {
+        return false;
+    }
+
+    bool maybeBool() const override
+    {
+        return m_value == "true" || m_value == "false";
+    }
+
+    bool maybeDouble() const override
+    {
+        const char *b = m_value.c_str();
+        char *e = nullptr;
+        strtod(b, &e);
+        return e != b && e == b + m_value.length();
+    }
+
+    bool maybeInteger() const override
+    {
+        std::istringstream i(m_value);
+        int64_t x;
+        char c;
+        if (!(i >> x) || i.get(c)) {
+            return false;
+        }
+
+        return true;
+    }
+
+    bool maybeNull() const override
+    {
+        return m_value.empty();
+    }
+
+    bool maybeObject() const override
+    {
+        return m_value.empty();
+    }
+
+    bool maybeString() const override
+    {
+        return true;
+    }
+
+private:
+    const std::string &m_value;
+};
+
+class StdStringArrayValueIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = StdStringAdapter;
+    using difference_type = StdStringAdapter;
+    using pointer = StdStringAdapter*;
+    using reference = StdStringAdapter&;
+
+    StdStringAdapter operator*() const
+    {
+        throwNotSupported();
+    }
+
+    DerefProxy<StdStringAdapter> operator->() const
+    {
+        throwNotSupported();
+    }
+
+    bool operator==(const StdStringArrayValueIterator &) const
+    {
+        return true;
+    }
+
+    bool operator!=(const StdStringArrayValueIterator &) const
+    {
+        return false;
+    }
+
+    const StdStringArrayValueIterator& operator++()
+    {
+        throwNotSupported();
+    }
+
+    StdStringArrayValueIterator operator++(int)
+    {
+        throwNotSupported();
+    }
+
+    const StdStringArrayValueIterator& operator--()
+    {
+        throwNotSupported();
+    }
+
+    void advance(std::ptrdiff_t)
+    {
+        throwNotSupported();
+    }
+};
+
+inline StdStringArrayValueIterator StdStringArray::begin() const
+{
+    return {};
+}
+
+inline StdStringArrayValueIterator StdStringArray::end() const
+{
+    return {};
+}
+
+class StdStringObjectMemberIterator
+{
+public:
+    using iterator_category = std::bidirectional_iterator_tag;
+    using value_type = StdStringObjectMember;
+    using difference_type = StdStringObjectMember;
+    using pointer = StdStringObjectMember*;
+    using reference = StdStringObjectMember&;
+
+    StdStringObjectMember operator*() const
+    {
+        throwNotSupported();
+    }
+
+    DerefProxy<StdStringObjectMember> operator->() const
+    {
+        throwNotSupported();
+    }
+
+    bool operator==(const StdStringObjectMemberIterator &) const
+    {
+        return true;
+    }
+
+    bool operator!=(const StdStringObjectMemberIterator &) const
+    {
+        return false;
+    }
+
+    const StdStringObjectMemberIterator& operator++()
+    {
+        throwNotSupported();
+    }
+
+    StdStringObjectMemberIterator operator++(int)
+    {
+        throwNotSupported();
+    }
+
+    const StdStringObjectMemberIterator& operator--()
+    {
+        throwNotSupported();
+    }
+};
+
+inline StdStringObjectMemberIterator StdStringObject::begin() const
+{
+    return {};
+}
+
+inline StdStringObjectMemberIterator StdStringObject::end() const
+{
+    return {};
+}
+
+inline StdStringObjectMemberIterator StdStringObject::find(const std::string &) const
+{
+    return {};
+}
+
+template<>
+struct AdapterTraits<valijson::adapters::StdStringAdapter>
+{
+    typedef std::string DocumentType;
+
+    static std::string adapterName()
+    {
+        return "StdStringAdapter";
+    }
+};
+
+inline bool StdStringFrozenValue::equalTo(const Adapter &other, bool strict) const
+{
+    return StdStringAdapter(value).equalTo(other, strict);
+}
+
+}  // namespace adapters
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/constraint_builder.hpp b/subprojects/valijson/include/valijson/constraint_builder.hpp
new file mode 100644
index 000000000..53407a95e
--- /dev/null
+++ b/subprojects/valijson/include/valijson/constraint_builder.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+namespace valijson {
+
+namespace adapters {
+    class Adapter;
+}
+
+namespace constraints {
+    struct Constraint;
+}
+
+class ConstraintBuilder
+{
+public:
+    virtual ~ConstraintBuilder() = default;
+
+    virtual constraints::Constraint * make(const adapters::Adapter &) const = 0;
+};
+
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/constraints/basic_constraint.hpp b/subprojects/valijson/include/valijson/constraints/basic_constraint.hpp
new file mode 100644
index 000000000..5de968318
--- /dev/null
+++ b/subprojects/valijson/include/valijson/constraints/basic_constraint.hpp
@@ -0,0 +1,55 @@
+#pragma once
+
+#include <valijson/constraints/constraint.hpp>
+#include <valijson/constraints/constraint_visitor.hpp>
+#include <valijson/internal/custom_allocator.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace constraints {
+
+/**
+ * @brief   Template class that implements the accept() and clone() functions of the Constraint interface.
+ *
+ * @tparam  ConstraintType   name of the concrete constraint type, which must provide a copy constructor.
+ */
+template<typename ConstraintType>
+struct BasicConstraint: Constraint
+{
+    typedef internal::CustomAllocator<void *> Allocator;
+
+    typedef std::basic_string<char, std::char_traits<char>, internal::CustomAllocator<char>> String;
+
+    BasicConstraint()
+      : m_allocator() { }
+
+    BasicConstraint(Allocator::CustomAlloc allocFn, Allocator::CustomFree freeFn)
+      : m_allocator(allocFn, freeFn) { }
+
+    BasicConstraint(const BasicConstraint &other)
+      : m_allocator(other.m_allocator) { }
+
+    ~BasicConstraint<ConstraintType>() override = default;
+
+    bool accept(ConstraintVisitor &visitor) const override
+    {
+        return visitor.visit(*static_cast<const ConstraintType*>(this));
+    }
+
+    Constraint * clone(CustomAlloc allocFn, CustomFree) const override
+    {
+        void *ptr = allocFn(sizeof(ConstraintType));
+        if (!ptr) {
+            throwRuntimeError("Failed to allocate memory for cloned constraint");
+        }
+
+        return new (ptr) ConstraintType(*static_cast<const ConstraintType*>(this));
+    }
+
+protected:
+
+    Allocator m_allocator;
+};
+
+} // namespace constraints
+} // namespace valijson
diff --git a/subprojects/valijson/include/valijson/constraints/concrete_constraints.hpp b/subprojects/valijson/include/valijson/constraints/concrete_constraints.hpp
new file mode 100644
index 000000000..55cc1248a
--- /dev/null
+++ b/subprojects/valijson/include/valijson/constraints/concrete_constraints.hpp
@@ -0,0 +1,1247 @@
+/**
+ * @file
+ *
+ * @brief   Class definitions to support JSON Schema constraints
+ *
+ * This file contains class definitions for all of the constraints required to
+ * support JSON Schema. These classes all inherit from the BasicConstraint
+ * template class, which implements the common parts of the Constraint
+ * interface.
+ *
+ * @see BasicConstraint
+ * @see Constraint
+ */
+
+#pragma once
+
+#include <limits>
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+
+#include <valijson/adapters/frozen_value.hpp>
+#include <valijson/constraints/basic_constraint.hpp>
+#include <valijson/internal/custom_allocator.hpp>
+#include <valijson/schema.hpp>
+#include <valijson/exceptions.hpp>
+
+#ifdef _MSC_VER
+#pragma warning( push )
+#pragma warning( disable : 4702 )
+#endif
+
+namespace valijson {
+
+class ValidationResults;
+
+namespace constraints {
+
+/**
+ * @brief  Represents an 'allOf' constraint.
+ *
+ * An allOf constraint provides a collection of sub-schemas that a value must
+ * validate against. If a value fails to validate against any of these sub-
+ * schemas, then validation fails.
+ */
+class AllOfConstraint: public BasicConstraint<AllOfConstraint>
+{
+public:
+    AllOfConstraint()
+      : m_subschemas(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    AllOfConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_subschemas(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    void addSubschema(const Subschema *subschema)
+    {
+        m_subschemas.push_back(subschema);
+    }
+
+    template<typename FunctorType>
+    void applyToSubschemas(const FunctorType &fn) const
+    {
+        unsigned int index = 0;
+        for (const Subschema *subschema : m_subschemas) {
+            if (!fn(index, subschema)) {
+                return;
+            }
+
+            index++;
+        }
+    }
+
+private:
+    typedef std::vector<const Subschema *, internal::CustomAllocator<const Subschema *>> Subschemas;
+
+    /// Collection of sub-schemas, all of which must be satisfied
+    Subschemas m_subschemas;
+};
+
+/**
+ * @brief  Represents an 'anyOf' constraint
+ *
+ * An anyOf constraint provides a collection of sub-schemas that a value can
+ * validate against. If a value validates against one of these sub-schemas,
+ * then the validation passes.
+ */
+class AnyOfConstraint: public BasicConstraint<AnyOfConstraint>
+{
+public:
+    AnyOfConstraint()
+      : m_subschemas(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    AnyOfConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_subschemas(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    void addSubschema(const Subschema *subschema)
+    {
+        m_subschemas.push_back(subschema);
+    }
+
+    template<typename FunctorType>
+    void applyToSubschemas(const FunctorType &fn) const
+    {
+        unsigned int index = 0;
+        for (const Subschema *subschema : m_subschemas) {
+            if (!fn(index, subschema)) {
+                return;
+            }
+
+            index++;
+        }
+    }
+
+private:
+    typedef std::vector<const Subschema *, internal::CustomAllocator<const Subschema *>> Subschemas;
+
+    /// Collection of sub-schemas, at least one of which must be satisfied
+    Subschemas m_subschemas;
+};
+
+/**
+ * @brief  Represents a combination 'if', 'then' and 'else' constraints
+ *
+ * The schema provided by an 'if' constraint is used as the expression for a conditional. When the
+ * target validates against that schema, the 'then' subschema will be also be tested. Otherwise,
+ * the 'else' subschema will be tested.
+ */
+class ConditionalConstraint: public BasicConstraint<ConditionalConstraint>
+{
+public:
+    ConditionalConstraint()
+      : m_ifSubschema(nullptr),
+        m_thenSubschema(nullptr),
+        m_elseSubschema(nullptr) { }
+
+    ConditionalConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_ifSubschema(nullptr),
+        m_thenSubschema(nullptr),
+        m_elseSubschema(nullptr) { }
+
+    const Subschema * getIfSubschema() const
+    {
+        return m_ifSubschema;
+    }
+
+    const Subschema * getThenSubschema() const
+    {
+        return m_thenSubschema;
+    }
+
+    const Subschema * getElseSubschema() const
+    {
+        return m_elseSubschema;
+    }
+
+    void setIfSubschema(const Subschema *subschema)
+    {
+        m_ifSubschema = subschema;
+    }
+
+    void setThenSubschema(const Subschema *subschema)
+    {
+        m_thenSubschema = subschema;
+    }
+
+    void setElseSubschema(const Subschema *subschema)
+    {
+        m_elseSubschema = subschema;
+    }
+
+private:
+    const Subschema *m_ifSubschema;
+    const Subschema *m_thenSubschema;
+    const Subschema *m_elseSubschema;
+};
+
+class ConstConstraint: public BasicConstraint<ConstConstraint>
+{
+public:
+    ConstConstraint()
+      : m_value(nullptr) { }
+
+    ConstConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_value(nullptr) { }
+
+    ConstConstraint(const ConstConstraint &other)
+      : BasicConstraint(other),
+        m_value(other.m_value->clone()) { }
+
+    adapters::FrozenValue * getValue() const
+    {
+        return m_value.get();
+    }
+
+    void setValue(const adapters::Adapter &value)
+    {
+        m_value = std::unique_ptr<adapters::FrozenValue>(value.freeze());
+    }
+
+private:
+    std::unique_ptr<adapters::FrozenValue> m_value;
+};
+
+/**
+ * @brief  Represents a 'contains' constraint
+ *
+ * A 'contains' constraint specifies a schema that must be satisfied by at least one
+ * of the values in an array.
+ */
+class ContainsConstraint: public BasicConstraint<ContainsConstraint>
+{
+public:
+    ContainsConstraint()
+      : m_subschema(nullptr) { }
+
+    ContainsConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_subschema(nullptr) { }
+
+    const Subschema * getSubschema() const
+    {
+        return m_subschema;
+    }
+
+    void setSubschema(const Subschema *subschema)
+    {
+        m_subschema = subschema;
+    }
+
+private:
+    const Subschema *m_subschema;
+};
+
+/**
+ * @brief  Represents a 'dependencies' constraint.
+ *
+ * A dependency constraint ensures that a given property is valid only if the
+ * properties that it depends on are present.
+ */
+class DependenciesConstraint: public BasicConstraint<DependenciesConstraint>
+{
+public:
+    DependenciesConstraint()
+      : m_propertyDependencies(std::less<String>(), m_allocator),
+        m_schemaDependencies(std::less<String>(), m_allocator)
+    { }
+
+    DependenciesConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_propertyDependencies(std::less<String>(), m_allocator),
+        m_schemaDependencies(std::less<String>(), m_allocator)
+    { }
+
+    template<typename StringType>
+    DependenciesConstraint & addPropertyDependency(
+            const StringType &propertyName,
+            const StringType &dependencyName)
+    {
+        const String key(propertyName.c_str(), m_allocator);
+        auto itr = m_propertyDependencies.find(key);
+        if (itr == m_propertyDependencies.end()) {
+            itr = m_propertyDependencies.insert(PropertyDependencies::value_type(
+                    key, PropertySet(std::less<String>(), m_allocator))).first;
+        }
+
+        itr->second.insert(String(dependencyName.c_str(), m_allocator));
+
+        return *this;
+    }
+
+    template<typename StringType, typename ContainerType>
+    DependenciesConstraint & addPropertyDependencies(
+            const StringType &propertyName,
+            const ContainerType &dependencyNames)
+    {
+        const String key(propertyName.c_str(), m_allocator);
+        auto itr = m_propertyDependencies.find(key);
+        if (itr == m_propertyDependencies.end()) {
+            itr = m_propertyDependencies.insert(PropertyDependencies::value_type(
+                    key, PropertySet(std::less<String>(), m_allocator))).first;
+        }
+
+        typedef typename ContainerType::value_type ValueType;
+        for (const ValueType &dependencyName : dependencyNames) {
+            itr->second.insert(String(dependencyName.c_str(), m_allocator));
+        }
+
+        return *this;
+    }
+
+    template<typename StringType>
+    DependenciesConstraint & addSchemaDependency(const StringType &propertyName, const Subschema *schemaDependency)
+    {
+        if (m_schemaDependencies.insert(SchemaDependencies::value_type(
+                String(propertyName.c_str(), m_allocator),
+                schemaDependency)).second) {
+            return *this;
+        }
+
+        throwRuntimeError("Dependencies constraint already contains a dependent "
+                "schema for the property '" + propertyName + "'");
+    }
+
+    template<typename FunctorType>
+    void applyToPropertyDependencies(const FunctorType &fn) const
+    {
+        for (const PropertyDependencies::value_type &v : m_propertyDependencies) {
+            if (!fn(v.first, v.second)) {
+                return;
+            }
+        }
+    }
+
+    template<typename FunctorType>
+    void applyToSchemaDependencies(const FunctorType &fn) const
+    {
+        for (const SchemaDependencies::value_type &v : m_schemaDependencies) {
+            if (!fn(v.first, v.second)) {
+                return;
+            }
+        }
+    }
+
+private:
+    typedef std::set<String, std::less<String>, internal::CustomAllocator<String>> PropertySet;
+
+    typedef std::map<String, PropertySet, std::less<String>,
+            internal::CustomAllocator<std::pair<const String, PropertySet>>> PropertyDependencies;
+
+    typedef std::map<String, const Subschema *, std::less<String>,
+            internal::CustomAllocator<std::pair<const String, const Subschema *>>> SchemaDependencies;
+
+    /// Mapping from property names to their property-based dependencies
+    PropertyDependencies m_propertyDependencies;
+
+    /// Mapping from property names to their schema-based dependencies
+    SchemaDependencies m_schemaDependencies;
+};
+
+/**
+ * @brief  Represents an 'enum' constraint
+ *
+ * An enum constraint provides a collection of permissible values for a JSON
+ * node. The node will only validate against this constraint if it matches one
+ * or more of the values in the collection.
+ */
+class EnumConstraint: public BasicConstraint<EnumConstraint>
+{
+public:
+    EnumConstraint()
+      : m_enumValues(Allocator::rebind<const EnumValue *>::other(m_allocator)) { }
+
+    EnumConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_enumValues(Allocator::rebind<const EnumValue *>::other(m_allocator)) { }
+
+    EnumConstraint(const EnumConstraint &other)
+      : BasicConstraint(other),
+        m_enumValues(Allocator::rebind<const EnumValue *>::other(m_allocator))
+    {
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            // Clone individual enum values
+            for (const EnumValue *otherValue : other.m_enumValues) {
+                const EnumValue *value = otherValue->clone();
+#if VALIJSON_USE_EXCEPTIONS
+                try {
+#endif
+                    m_enumValues.push_back(value);
+#if VALIJSON_USE_EXCEPTIONS
+                } catch (...) {
+                    delete value;
+                    value = nullptr;
+                    throw;
+                }
+            }
+        } catch (...) {
+            // Delete values already added to constraint
+            for (const EnumValue *value : m_enumValues) {
+                delete value;
+            }
+            throw;
+#endif
+        }
+    }
+
+    ~EnumConstraint() override
+    {
+        for (const EnumValue *value : m_enumValues) {
+            delete value;
+        }
+    }
+
+    void addValue(const adapters::Adapter &value)
+    {
+        // TODO: Freeze value using custom alloc/free functions
+        m_enumValues.push_back(value.freeze());
+    }
+
+    void addValue(const adapters::FrozenValue &value)
+    {
+        // TODO: Clone using custom alloc/free functions
+        m_enumValues.push_back(value.clone());
+    }
+
+    template<typename FunctorType>
+    void applyToValues(const FunctorType &fn) const
+    {
+        for (const EnumValue *value : m_enumValues) {
+            if (!fn(*value)) {
+                return;
+            }
+        }
+    }
+
+private:
+    typedef adapters::FrozenValue EnumValue;
+
+    typedef std::vector<const EnumValue *, internal::CustomAllocator<const EnumValue *>> EnumValues;
+
+    EnumValues m_enumValues;
+};
+
+/**
+ * @brief  Represents non-singular 'items' and 'additionalItems' constraints
+ *
+ * Unlike the SingularItemsConstraint class, this class represents an 'items'
+ * constraint that specifies an array of sub-schemas, which should be used to
+ * validate each item in an array, in sequence. It also represents an optional
+ * 'additionalItems' sub-schema that should be used when an array contains
+ * more values than there are sub-schemas in the 'items' constraint.
+ *
+ * The prefix 'Linear' comes from the fact that this class contains a list of
+ * sub-schemas that corresponding array items must be validated against, and
+ * this validation is performed linearly (i.e. in sequence).
+ */
+class LinearItemsConstraint: public BasicConstraint<LinearItemsConstraint>
+{
+public:
+    LinearItemsConstraint()
+      : m_itemSubschemas(Allocator::rebind<const Subschema *>::other(m_allocator)),
+        m_additionalItemsSubschema(nullptr) { }
+
+    LinearItemsConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_itemSubschemas(Allocator::rebind<const Subschema *>::other(m_allocator)),
+        m_additionalItemsSubschema(nullptr) { }
+
+    void addItemSubschema(const Subschema *subschema)
+    {
+        m_itemSubschemas.push_back(subschema);
+    }
+
+    template<typename FunctorType>
+    void applyToItemSubschemas(const FunctorType &fn) const
+    {
+        unsigned int index = 0;
+        for (const Subschema *subschema : m_itemSubschemas) {
+            if (!fn(index, subschema)) {
+                return;
+            }
+
+            index++;
+        }
+    }
+
+    const Subschema * getAdditionalItemsSubschema() const
+    {
+        return m_additionalItemsSubschema;
+    }
+
+    size_t getItemSubschemaCount() const
+    {
+        return m_itemSubschemas.size();
+    }
+
+    void setAdditionalItemsSubschema(const Subschema *subschema)
+    {
+        m_additionalItemsSubschema = subschema;
+    }
+
+private:
+    typedef std::vector<const Subschema *, internal::CustomAllocator<const Subschema *>> Subschemas;
+
+    Subschemas m_itemSubschemas;
+
+    const Subschema* m_additionalItemsSubschema;
+};
+
+/**
+ * @brief   Represents 'maximum' and 'exclusiveMaximum' constraints
+ */
+class MaximumConstraint: public BasicConstraint<MaximumConstraint>
+{
+public:
+    MaximumConstraint()
+      : m_maximum(std::numeric_limits<double>::infinity()),
+        m_exclusiveMaximum(false) { }
+
+    MaximumConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_maximum(std::numeric_limits<double>::infinity()),
+        m_exclusiveMaximum(false) { }
+
+    bool getExclusiveMaximum() const
+    {
+        return m_exclusiveMaximum;
+    }
+
+    void setExclusiveMaximum(bool newExclusiveMaximum)
+    {
+        m_exclusiveMaximum = newExclusiveMaximum;
+    }
+
+    double getMaximum() const
+    {
+        return m_maximum;
+    }
+
+    void setMaximum(double newMaximum)
+    {
+        m_maximum = newMaximum;
+    }
+
+private:
+    double m_maximum;
+    bool m_exclusiveMaximum;
+};
+
+/**
+ * @brief   Represents a 'maxItems' constraint
+ */
+class MaxItemsConstraint: public BasicConstraint<MaxItemsConstraint>
+{
+public:
+    MaxItemsConstraint()
+      : m_maxItems(std::numeric_limits<uint64_t>::max()) { }
+
+    MaxItemsConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_maxItems(std::numeric_limits<uint64_t>::max()) { }
+
+    uint64_t getMaxItems() const
+    {
+        return m_maxItems;
+    }
+
+    void setMaxItems(uint64_t newMaxItems)
+    {
+        m_maxItems = newMaxItems;
+    }
+
+private:
+    uint64_t m_maxItems;
+};
+
+/**
+ * @brief   Represents a 'maxLength' constraint
+ */
+class MaxLengthConstraint: public BasicConstraint<MaxLengthConstraint>
+{
+public:
+    MaxLengthConstraint()
+      : m_maxLength(std::numeric_limits<uint64_t>::max()) { }
+
+    MaxLengthConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_maxLength(std::numeric_limits<uint64_t>::max()) { }
+
+    uint64_t getMaxLength() const
+    {
+        return m_maxLength;
+    }
+
+    void setMaxLength(uint64_t newMaxLength)
+    {
+        m_maxLength = newMaxLength;
+    }
+
+private:
+    uint64_t m_maxLength;
+};
+
+/**
+ * @brief   Represents a 'maxProperties' constraint
+ */
+class MaxPropertiesConstraint: public BasicConstraint<MaxPropertiesConstraint>
+{
+public:
+    MaxPropertiesConstraint()
+      : m_maxProperties(std::numeric_limits<uint64_t>::max()) { }
+
+    MaxPropertiesConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_maxProperties(std::numeric_limits<uint64_t>::max()) { }
+
+    uint64_t getMaxProperties() const
+    {
+        return m_maxProperties;
+    }
+
+    void setMaxProperties(uint64_t newMaxProperties)
+    {
+        m_maxProperties = newMaxProperties;
+    }
+
+private:
+    uint64_t m_maxProperties;
+};
+
+/**
+ * @brief   Represents 'minimum' and 'exclusiveMinimum' constraints
+ */
+class MinimumConstraint: public BasicConstraint<MinimumConstraint>
+{
+public:
+    MinimumConstraint()
+      : m_minimum(-std::numeric_limits<double>::infinity()),
+        m_exclusiveMinimum(false) { }
+
+    MinimumConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_minimum(-std::numeric_limits<double>::infinity()),
+        m_exclusiveMinimum(false) { }
+
+    bool getExclusiveMinimum() const
+    {
+        return m_exclusiveMinimum;
+    }
+
+    void setExclusiveMinimum(bool newExclusiveMinimum)
+    {
+        m_exclusiveMinimum = newExclusiveMinimum;
+    }
+
+    double getMinimum() const
+    {
+        return m_minimum;
+    }
+
+    void setMinimum(double newMinimum)
+    {
+        m_minimum = newMinimum;
+    }
+
+private:
+    double m_minimum;
+    bool m_exclusiveMinimum;
+};
+
+/**
+ * @brief   Represents a 'minItems' constraint
+ */
+class MinItemsConstraint: public BasicConstraint<MinItemsConstraint>
+{
+public:
+    MinItemsConstraint()
+      : m_minItems(0) { }
+
+    MinItemsConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_minItems(0) { }
+
+    uint64_t getMinItems() const
+    {
+        return m_minItems;
+    }
+
+    void setMinItems(uint64_t newMinItems)
+    {
+        m_minItems = newMinItems;
+    }
+
+private:
+    uint64_t m_minItems;
+};
+
+/**
+ * @brief   Represents a 'minLength' constraint
+ */
+class MinLengthConstraint: public BasicConstraint<MinLengthConstraint>
+{
+public:
+    MinLengthConstraint()
+      : m_minLength(0) { }
+
+    MinLengthConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_minLength(0) { }
+
+    uint64_t getMinLength() const
+    {
+        return m_minLength;
+    }
+
+    void setMinLength(uint64_t newMinLength)
+    {
+        m_minLength = newMinLength;
+    }
+
+private:
+    uint64_t m_minLength;
+};
+
+/**
+ * @brief   Represents a 'minProperties' constraint
+ */
+class MinPropertiesConstraint: public BasicConstraint<MinPropertiesConstraint>
+{
+public:
+    MinPropertiesConstraint()
+      : m_minProperties(0) { }
+
+    MinPropertiesConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_minProperties(0) { }
+
+    uint64_t getMinProperties() const
+    {
+        return m_minProperties;
+    }
+
+    void setMinProperties(uint64_t newMinProperties)
+    {
+        m_minProperties = newMinProperties;
+    }
+
+private:
+    uint64_t m_minProperties;
+};
+
+/**
+ * @brief  Represents either 'multipleOf' or 'divisibleBy' constraints where
+ *         the divisor is a floating point number
+ */
+class MultipleOfDoubleConstraint:
+        public BasicConstraint<MultipleOfDoubleConstraint>
+{
+public:
+    MultipleOfDoubleConstraint()
+      : m_value(1.) { }
+
+    MultipleOfDoubleConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_value(1.) { }
+
+    double getDivisor() const
+    {
+        return m_value;
+    }
+
+    void setDivisor(double newValue)
+    {
+        m_value = newValue;
+    }
+
+private:
+    double m_value;
+};
+
+/**
+ * @brief  Represents either 'multipleOf' or 'divisibleBy' constraints where
+ *         the divisor is of integer type
+ */
+class MultipleOfIntConstraint:
+        public BasicConstraint<MultipleOfIntConstraint>
+{
+public:
+    MultipleOfIntConstraint()
+      : m_value(1) { }
+
+    MultipleOfIntConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_value(1) { }
+
+    int64_t getDivisor() const
+    {
+        return m_value;
+    }
+
+    void setDivisor(int64_t newValue)
+    {
+        m_value = newValue;
+    }
+
+private:
+    int64_t m_value;
+};
+
+/**
+ * @brief   Represents a 'not' constraint
+ */
+class NotConstraint: public BasicConstraint<NotConstraint>
+{
+public:
+    NotConstraint()
+      : m_subschema(nullptr) { }
+
+    NotConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_subschema(nullptr) { }
+
+    const Subschema * getSubschema() const
+    {
+        return m_subschema;
+    }
+
+    void setSubschema(const Subschema *subschema)
+    {
+        m_subschema = subschema;
+    }
+
+private:
+    const Subschema *m_subschema;
+};
+
+/**
+ * @brief   Represents a 'oneOf' constraint.
+ */
+class OneOfConstraint: public BasicConstraint<OneOfConstraint>
+{
+public:
+    OneOfConstraint()
+      : m_subschemas(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    OneOfConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_subschemas(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    void addSubschema(const Subschema *subschema)
+    {
+        m_subschemas.push_back(subschema);
+    }
+
+    template<typename FunctorType>
+    void applyToSubschemas(const FunctorType &fn) const
+    {
+        unsigned int index = 0;
+        for (const Subschema *subschema : m_subschemas) {
+            if (!fn(index, subschema)) {
+                return;
+            }
+
+            index++;
+        }
+    }
+
+private:
+    typedef std::vector<const Subschema *, internal::CustomAllocator<const Subschema *>> Subschemas;
+
+    /// Collection of sub-schemas, exactly one of which must be satisfied
+    Subschemas m_subschemas;
+};
+
+/**
+ * @brief   Represents a 'pattern' constraint
+ */
+class PatternConstraint: public BasicConstraint<PatternConstraint>
+{
+public:
+    PatternConstraint()
+      : m_pattern(Allocator::rebind<char>::other(m_allocator)) { }
+
+    PatternConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_pattern(Allocator::rebind<char>::other(m_allocator)) { }
+
+    template<typename AllocatorType>
+    bool getPattern(std::basic_string<char, std::char_traits<char>, AllocatorType> &result) const
+    {
+        result.assign(m_pattern.c_str());
+        return true;
+    }
+
+    template<typename AllocatorType>
+    std::basic_string<char, std::char_traits<char>, AllocatorType> getPattern(
+            const AllocatorType &alloc = AllocatorType()) const
+    {
+        return std::basic_string<char, std::char_traits<char>, AllocatorType>(m_pattern.c_str(), alloc);
+    }
+
+    template<typename AllocatorType>
+    void setPattern(const std::basic_string<char, std::char_traits<char>, AllocatorType> &pattern)
+    {
+        m_pattern.assign(pattern.c_str());
+    }
+
+private:
+    String m_pattern;
+};
+
+class PolyConstraint : public Constraint
+{
+public:
+    bool accept(ConstraintVisitor &visitor) const override
+    {
+        return visitor.visit(*static_cast<const PolyConstraint*>(this));
+    }
+
+    Constraint * clone(CustomAlloc allocFn, CustomFree freeFn) const override
+    {
+        void *ptr = allocFn(sizeOf());
+        if (!ptr) {
+            throwRuntimeError("Failed to allocate memory for cloned constraint");
+        }
+
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            return cloneInto(ptr);
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (...) {
+            freeFn(ptr);
+            throw;
+        }
+#else
+        // pretend to use freeFn to avoid warning in GCC 8.3
+        (void)freeFn;
+#endif
+    }
+
+    virtual bool validate(const adapters::Adapter &target,
+            const std::vector<std::string>& context,
+            valijson::ValidationResults *results) const = 0;
+
+private:
+    virtual Constraint * cloneInto(void *) const = 0;
+
+    virtual size_t sizeOf() const = 0;
+};
+
+/**
+ * @brief   Represents a combination of 'properties', 'patternProperties' and
+ *          'additionalProperties' constraints
+ */
+class PropertiesConstraint: public BasicConstraint<PropertiesConstraint>
+{
+public:
+    PropertiesConstraint()
+      : m_properties(std::less<String>(), m_allocator),
+        m_patternProperties(std::less<String>(), m_allocator),
+        m_additionalProperties(nullptr) { }
+
+    PropertiesConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_properties(std::less<String>(), m_allocator),
+        m_patternProperties(std::less<String>(), m_allocator),
+        m_additionalProperties(nullptr) { }
+
+    bool addPatternPropertySubschema(const char *patternProperty, const Subschema *subschema)
+    {
+        return m_patternProperties.insert(PropertySchemaMap::value_type(
+                String(patternProperty, m_allocator), subschema)).second;
+    }
+
+    template<typename AllocatorType>
+    bool addPatternPropertySubschema(const std::basic_string<char,
+            std::char_traits<char>, AllocatorType> &patternProperty,
+            const Subschema *subschema)
+    {
+        return addPatternPropertySubschema(patternProperty.c_str(), subschema);
+    }
+
+    bool addPropertySubschema(const char *propertyName,
+            const Subschema *subschema)
+    {
+        return m_properties.insert(PropertySchemaMap::value_type(
+                String(propertyName, m_allocator), subschema)).second;
+    }
+
+    template<typename AllocatorType>
+    bool addPropertySubschema(const std::basic_string<char,
+            std::char_traits<char>, AllocatorType> &propertyName,
+            const Subschema *subschema)
+    {
+        return addPropertySubschema(propertyName.c_str(), subschema);
+    }
+
+    template<typename FunctorType>
+    void applyToPatternProperties(const FunctorType &fn) const
+    {
+        typedef typename PropertySchemaMap::value_type ValueType;
+        for (const ValueType &value : m_patternProperties) {
+            if (!fn(value.first, value.second)) {
+                return;
+            }
+        }
+    }
+
+    template<typename FunctorType>
+    void applyToProperties(const FunctorType &fn) const
+    {
+        typedef typename PropertySchemaMap::value_type ValueType;
+        for (const ValueType &value : m_properties) {
+            if (!fn(value.first, value.second)) {
+                return;
+            }
+        }
+    }
+
+    const Subschema * getAdditionalPropertiesSubschema() const
+    {
+        return m_additionalProperties;
+    }
+
+    void setAdditionalPropertiesSubschema(const Subschema *subschema)
+    {
+        m_additionalProperties = subschema;
+    }
+
+private:
+    typedef std::map<
+            String,
+            const Subschema *,
+            std::less<String>,
+            internal::CustomAllocator<std::pair<const String, const Subschema *>>
+        > PropertySchemaMap;
+
+    PropertySchemaMap m_properties;
+    PropertySchemaMap m_patternProperties;
+
+    const Subschema *m_additionalProperties;
+};
+
+class PropertyNamesConstraint: public BasicConstraint<PropertyNamesConstraint>
+{
+public:
+    PropertyNamesConstraint()
+      : m_subschema(nullptr) { }
+
+    PropertyNamesConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_subschema(nullptr) { }
+
+    const Subschema * getSubschema() const
+    {
+        return m_subschema;
+    }
+
+    void setSubschema(const Subschema *subschema)
+    {
+        m_subschema = subschema;
+    }
+
+private:
+    const Subschema *m_subschema;
+};
+
+/**
+ * @brief   Represents a 'required' constraint
+ */
+class RequiredConstraint: public BasicConstraint<RequiredConstraint>
+{
+public:
+    RequiredConstraint()
+      : m_requiredProperties(std::less<String>(), m_allocator) { }
+
+    RequiredConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_requiredProperties(std::less<String>(), m_allocator) { }
+
+    bool addRequiredProperty(const char *propertyName)
+    {
+        return m_requiredProperties.insert(String(propertyName,
+                Allocator::rebind<char>::other(m_allocator))).second;
+    }
+
+    template<typename AllocatorType>
+    bool addRequiredProperty(const std::basic_string<char, std::char_traits<char>, AllocatorType> &propertyName)
+    {
+        return addRequiredProperty(propertyName.c_str());
+    }
+
+    template<typename FunctorType>
+    void applyToRequiredProperties(const FunctorType &fn) const
+    {
+        for (const String &propertyName : m_requiredProperties) {
+            if (!fn(propertyName)) {
+                return;
+            }
+        }
+    }
+
+private:
+    typedef std::set<String, std::less<String>,
+            internal::CustomAllocator<String>> RequiredProperties;
+
+    RequiredProperties m_requiredProperties;
+};
+
+/**
+ * @brief  Represents an 'items' constraint that specifies one sub-schema
+ *
+ * A value is considered valid against this constraint if it is an array, and
+ * each item in the array validates against the sub-schema specified by this
+ * constraint.
+ *
+ * The prefix 'Singular' comes from the fact that array items must validate
+ * against exactly one sub-schema.
+ */
+class SingularItemsConstraint: public BasicConstraint<SingularItemsConstraint>
+{
+public:
+    SingularItemsConstraint()
+      : m_itemsSubschema(nullptr) { }
+
+    SingularItemsConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_itemsSubschema(nullptr) { }
+
+    const Subschema * getItemsSubschema() const
+    {
+        return m_itemsSubschema;
+    }
+
+    void setItemsSubschema(const Subschema *subschema)
+    {
+        m_itemsSubschema = subschema;
+    }
+
+private:
+    const Subschema *m_itemsSubschema;
+};
+
+/**
+ * @brief   Represents a 'type' constraint.
+ */
+class TypeConstraint: public BasicConstraint<TypeConstraint>
+{
+public:
+    enum JsonType {
+        kAny,
+        kArray,
+        kBoolean,
+        kInteger,
+        kNull,
+        kNumber,
+        kObject,
+        kString
+    };
+
+    TypeConstraint()
+      : m_namedTypes(std::less<JsonType>(), m_allocator),
+        m_schemaTypes(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    TypeConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn),
+        m_namedTypes(std::less<JsonType>(), m_allocator),
+        m_schemaTypes(Allocator::rebind<const Subschema *>::other(m_allocator)) { }
+
+    void addNamedType(JsonType type)
+    {
+        m_namedTypes.insert(type);
+    }
+
+    void addSchemaType(const Subschema *subschema)
+    {
+        m_schemaTypes.push_back(subschema);
+    }
+
+    template<typename FunctorType>
+    void applyToNamedTypes(const FunctorType &fn) const
+    {
+        for (const JsonType namedType : m_namedTypes) {
+            if (!fn(namedType)) {
+                return;
+            }
+        }
+    }
+
+    template<typename FunctorType>
+    void applyToSchemaTypes(const FunctorType &fn) const
+    {
+        unsigned int index = 0;
+        for (const Subschema *subschema : m_schemaTypes) {
+            if (!fn(index, subschema)) {
+                return;
+            }
+
+            index++;
+        }
+    }
+
+    template<typename AllocatorType>
+    static JsonType jsonTypeFromString(const std::basic_string<char,
+            std::char_traits<char>, AllocatorType> &typeName)
+    {
+        if (typeName.compare("any") == 0) {
+            return kAny;
+        } else if (typeName.compare("array") == 0) {
+            return kArray;
+        } else if (typeName.compare("boolean") == 0) {
+            return kBoolean;
+        } else if (typeName.compare("integer") == 0) {
+            return kInteger;
+        } else if (typeName.compare("null") == 0) {
+            return kNull;
+        } else if (typeName.compare("number") == 0) {
+            return kNumber;
+        } else if (typeName.compare("object") == 0) {
+            return kObject;
+        } else if (typeName.compare("string") == 0) {
+            return kString;
+        }
+
+        throwRuntimeError("Unrecognised JSON type name '" +
+                std::string(typeName.c_str()) + "'");
+        abort();
+    }
+
+private:
+    typedef std::set<JsonType, std::less<JsonType>, internal::CustomAllocator<JsonType>> NamedTypes;
+
+    typedef std::vector<const Subschema *,
+            Allocator::rebind<const Subschema *>::other> SchemaTypes;
+
+    /// Set of named JSON types that serve as valid types
+    NamedTypes m_namedTypes;
+
+    /// Set of sub-schemas that serve as valid types
+    SchemaTypes m_schemaTypes;
+};
+
+/**
+ * @brief   Represents a 'uniqueItems' constraint
+ */
+class UniqueItemsConstraint: public BasicConstraint<UniqueItemsConstraint>
+{
+public:
+    UniqueItemsConstraint() = default;
+
+    UniqueItemsConstraint(CustomAlloc allocFn, CustomFree freeFn)
+      : BasicConstraint(allocFn, freeFn) { }
+};
+
+} // namespace constraints
+} // namespace valijson
+
+#ifdef _MSC_VER
+#pragma warning( pop )
+#endif
diff --git a/subprojects/valijson/include/valijson/constraints/constraint.hpp b/subprojects/valijson/include/valijson/constraints/constraint.hpp
new file mode 100644
index 000000000..03b6444cd
--- /dev/null
+++ b/subprojects/valijson/include/valijson/constraints/constraint.hpp
@@ -0,0 +1,50 @@
+#pragma once
+
+namespace valijson {
+namespace constraints {
+
+class ConstraintVisitor;
+
+/**
+ * @brief  Interface that must be implemented by concrete constraint types.
+ *
+ * @todo  Consider using something like the boost::cloneable concept here.
+ */
+struct Constraint
+{
+    /// Typedef for custom new-/malloc-like function
+    typedef void * (*CustomAlloc)(size_t size);
+
+    /// Typedef for custom free-like function
+    typedef void (*CustomFree)(void *);
+
+    /**
+     * @brief  Virtual destructor.
+     */
+    virtual ~Constraint() = default;
+
+    /**
+     * @brief  Perform an action on the constraint using the visitor pattern.
+     *
+     * Note that Constraints cannot be modified by visitors.
+     *
+     * @param  visitor  Reference to a ConstraintVisitor object.
+     *
+     * @returns  the boolean value returned by one of the visitor's visit
+     *           functions.
+     */
+    virtual bool accept(ConstraintVisitor &visitor) const = 0;
+
+    /**
+     * @brief  Make a copy of a constraint.
+     *
+     * Note that this should be a deep copy of the constraint.
+     *
+     * @returns  an owning-pointer to the new constraint.
+     */
+    virtual Constraint * clone(CustomAlloc, CustomFree) const = 0;
+
+};
+
+} // namespace constraints
+} // namespace valijson
diff --git a/subprojects/valijson/include/valijson/constraints/constraint_visitor.hpp b/subprojects/valijson/include/valijson/constraints/constraint_visitor.hpp
new file mode 100644
index 000000000..da3f3d7cf
--- /dev/null
+++ b/subprojects/valijson/include/valijson/constraints/constraint_visitor.hpp
@@ -0,0 +1,104 @@
+#pragma once
+
+namespace valijson {
+namespace constraints {
+
+class AllOfConstraint;
+class AnyOfConstraint;
+class ConditionalConstraint;
+class ConstConstraint;
+class ContainsConstraint;
+class DependenciesConstraint;
+class EnumConstraint;
+class LinearItemsConstraint;
+class MaxItemsConstraint;
+class MaximumConstraint;
+class MaxLengthConstraint;
+class MaxPropertiesConstraint;
+class MinItemsConstraint;
+class MinimumConstraint;
+class MinLengthConstraint;
+class MinPropertiesConstraint;
+class MultipleOfDoubleConstraint;
+class MultipleOfIntConstraint;
+class NotConstraint;
+class OneOfConstraint;
+class PatternConstraint;
+class PolyConstraint;
+class PropertiesConstraint;
+class PropertyNamesConstraint;
+class RequiredConstraint;
+class SingularItemsConstraint;
+class TypeConstraint;
+class UniqueItemsConstraint;
+
+/// Interface to allow usage of the visitor pattern with Constraints
+class ConstraintVisitor
+{
+protected:
+    virtual ~ConstraintVisitor() = default;
+
+    // Shorten type names for derived classes outside of this namespace
+    typedef constraints::AllOfConstraint AllOfConstraint;
+    typedef constraints::AnyOfConstraint AnyOfConstraint;
+    typedef constraints::ConditionalConstraint ConditionalConstraint;
+    typedef constraints::ConstConstraint ConstConstraint;
+    typedef constraints::ContainsConstraint ContainsConstraint;
+    typedef constraints::DependenciesConstraint DependenciesConstraint;
+    typedef constraints::EnumConstraint EnumConstraint;
+    typedef constraints::LinearItemsConstraint LinearItemsConstraint;
+    typedef constraints::MaximumConstraint MaximumConstraint;
+    typedef constraints::MaxItemsConstraint MaxItemsConstraint;
+    typedef constraints::MaxLengthConstraint MaxLengthConstraint;
+    typedef constraints::MaxPropertiesConstraint MaxPropertiesConstraint;
+    typedef constraints::MinimumConstraint MinimumConstraint;
+    typedef constraints::MinItemsConstraint MinItemsConstraint;
+    typedef constraints::MinLengthConstraint MinLengthConstraint;
+    typedef constraints::MinPropertiesConstraint MinPropertiesConstraint;
+    typedef constraints::MultipleOfDoubleConstraint MultipleOfDoubleConstraint;
+    typedef constraints::MultipleOfIntConstraint MultipleOfIntConstraint;
+    typedef constraints::NotConstraint NotConstraint;
+    typedef constraints::OneOfConstraint OneOfConstraint;
+    typedef constraints::PatternConstraint PatternConstraint;
+    typedef constraints::PolyConstraint PolyConstraint;
+    typedef constraints::PropertiesConstraint PropertiesConstraint;
+    typedef constraints::PropertyNamesConstraint PropertyNamesConstraint;
+    typedef constraints::RequiredConstraint RequiredConstraint;
+    typedef constraints::SingularItemsConstraint SingularItemsConstraint;
+    typedef constraints::TypeConstraint TypeConstraint;
+    typedef constraints::UniqueItemsConstraint UniqueItemsConstraint;
+
+public:
+
+    virtual bool visit(const AllOfConstraint &) = 0;
+    virtual bool visit(const AnyOfConstraint &) = 0;
+    virtual bool visit(const ConditionalConstraint &) = 0;
+    virtual bool visit(const ConstConstraint &) = 0;
+    virtual bool visit(const ContainsConstraint &) = 0;
+    virtual bool visit(const DependenciesConstraint &) = 0;
+    virtual bool visit(const EnumConstraint &) = 0;
+    virtual bool visit(const LinearItemsConstraint &) = 0;
+    virtual bool visit(const MaximumConstraint &) = 0;
+    virtual bool visit(const MaxItemsConstraint &) = 0;
+    virtual bool visit(const MaxLengthConstraint &) = 0;
+    virtual bool visit(const MaxPropertiesConstraint &) = 0;
+    virtual bool visit(const MinimumConstraint &) = 0;
+    virtual bool visit(const MinItemsConstraint &) = 0;
+    virtual bool visit(const MinLengthConstraint &) = 0;
+    virtual bool visit(const MinPropertiesConstraint &) = 0;
+    virtual bool visit(const MultipleOfDoubleConstraint &) = 0;
+    virtual bool visit(const MultipleOfIntConstraint &) = 0;
+    virtual bool visit(const NotConstraint &) = 0;
+    virtual bool visit(const OneOfConstraint &) = 0;
+    virtual bool visit(const PatternConstraint &) = 0;
+    virtual bool visit(const PolyConstraint &) = 0;
+    virtual bool visit(const PropertiesConstraint &) = 0;
+    virtual bool visit(const PropertyNamesConstraint &) = 0;
+    virtual bool visit(const RequiredConstraint &) = 0;
+    virtual bool visit(const SingularItemsConstraint &) = 0;
+    virtual bool visit(const TypeConstraint &) = 0;
+    virtual bool visit(const UniqueItemsConstraint &) = 0;
+};
+
+}  // namespace constraints
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/exceptions.hpp b/subprojects/valijson/include/valijson/exceptions.hpp
new file mode 100644
index 000000000..a4188259e
--- /dev/null
+++ b/subprojects/valijson/include/valijson/exceptions.hpp
@@ -0,0 +1,41 @@
+#pragma once
+
+#include <iostream>
+#include <exception>
+
+namespace valijson {
+#if defined(_MSC_VER) && _MSC_VER == 1800
+#define VALIJSON_NORETURN __declspec(noreturn)
+#else
+#define VALIJSON_NORETURN [[noreturn]]
+#endif
+
+#if VALIJSON_USE_EXCEPTIONS
+#include <stdexcept>
+
+VALIJSON_NORETURN inline void throwRuntimeError(const std::string& msg) {
+  throw std::runtime_error(msg);
+}
+
+VALIJSON_NORETURN inline void throwLogicError(const std::string& msg) {
+  throw std::logic_error(msg);
+}
+#else
+VALIJSON_NORETURN inline void throwRuntimeError(const std::string& msg) {
+  std::cerr << msg << std::endl;
+  abort();
+}
+VALIJSON_NORETURN inline void throwLogicError(const std::string& msg) {
+  std::cerr << msg << std::endl;
+  abort();
+}
+
+#endif
+
+VALIJSON_NORETURN inline void throwNotSupported() {
+    throwRuntimeError("Not supported");                             \
+}
+
+} // namespace valijson
+
+
diff --git a/subprojects/valijson/include/valijson/internal/custom_allocator.hpp b/subprojects/valijson/include/valijson/internal/custom_allocator.hpp
new file mode 100644
index 000000000..07e1d6117
--- /dev/null
+++ b/subprojects/valijson/include/valijson/internal/custom_allocator.hpp
@@ -0,0 +1,107 @@
+#pragma once
+
+namespace valijson {
+namespace internal {
+
+template<class T>
+class CustomAllocator
+{
+public:
+    /// Typedef for custom new-/malloc-like function
+    typedef void * (*CustomAlloc)(size_t size);
+
+    /// Typedef for custom free-like function
+    typedef void (*CustomFree)(void *);
+
+    // Standard allocator typedefs
+    typedef T value_type;
+    typedef T* pointer;
+    typedef const T* const_pointer;
+    typedef T& reference;
+    typedef const T& const_reference;
+    typedef std::size_t size_type;
+    typedef std::ptrdiff_t difference_type;
+
+    template<typename U>
+    struct rebind
+    {
+        typedef CustomAllocator<U> other;
+    };
+
+    CustomAllocator()
+      : m_allocFn(::operator new),
+        m_freeFn(::operator delete) { }
+
+    CustomAllocator(CustomAlloc allocFn, CustomFree freeFn)
+      : m_allocFn(allocFn),
+        m_freeFn(freeFn) { }
+
+    CustomAllocator(const CustomAllocator &other)
+      : m_allocFn(other.m_allocFn),
+        m_freeFn(other.m_freeFn) { }
+
+    template<typename U>
+    CustomAllocator(CustomAllocator<U> const &other)
+      : m_allocFn(other.m_allocFn),
+        m_freeFn(other.m_freeFn) { }
+
+    CustomAllocator & operator=(const CustomAllocator &other)
+    {
+        m_allocFn = other.m_allocFn;
+        m_freeFn = other.m_freeFn;
+
+        return *this;
+    }
+
+    pointer address(reference r)
+    {
+        return &r;
+    }
+
+    const_pointer address(const_reference r)
+    {
+        return &r;
+    }
+
+    pointer allocate(size_type cnt, const void * = nullptr)
+    {
+        return reinterpret_cast<pointer>(m_allocFn(cnt * sizeof(T)));
+    }
+
+    void deallocate(pointer p, size_type)
+    {
+        m_freeFn(p);
+    }
+
+    size_type max_size() const
+    {
+        return std::numeric_limits<size_type>::max() / sizeof(T);
+    }
+
+    void construct(pointer p, const T& t)
+    {
+        new(p) T(t);
+    }
+
+    void destroy(pointer p)
+    {
+        p->~T();
+    }
+
+    bool operator==(const CustomAllocator &other) const
+    {
+        return other.m_allocFn == m_allocFn && other.m_freeFn == m_freeFn;
+    }
+
+    bool operator!=(const CustomAllocator &other) const
+    {
+        return !operator==(other);
+    }
+
+    CustomAlloc m_allocFn;
+
+    CustomFree m_freeFn;
+};
+
+} // end namespace internal
+} // end namespace valijson
diff --git a/subprojects/valijson/include/valijson/internal/debug.hpp b/subprojects/valijson/include/valijson/internal/debug.hpp
new file mode 100644
index 000000000..25c3dd770
--- /dev/null
+++ b/subprojects/valijson/include/valijson/internal/debug.hpp
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <string>
+
+namespace valijson {
+namespace internal {
+
+template<typename AdapterType>
+std::string nodeTypeAsString(const AdapterType &node) {
+    if (node.isArray()) {
+        return "array";
+    } else if (node.isObject()) {
+        return "object";
+    } else if (node.isString()) {
+        return "string";
+    } else if (node.isNull()) {
+        return "null";
+    } else if (node.isInteger()) {
+        return "integer";
+    } else if (node.isDouble()) {
+        return "double";
+    } else if (node.isBool()) {
+        return "bool";
+    }
+
+    return "unknown";
+}
+
+} // end namespace internal
+} // end namespace valijson
diff --git a/subprojects/valijson/include/valijson/internal/json_pointer.hpp b/subprojects/valijson/include/valijson/internal/json_pointer.hpp
new file mode 100644
index 000000000..b290c02a2
--- /dev/null
+++ b/subprojects/valijson/include/valijson/internal/json_pointer.hpp
@@ -0,0 +1,275 @@
+#pragma once
+
+#include <algorithm>
+#include <cerrno>
+#include <cstddef>
+#include <cstring>
+#include <stdexcept>
+#include <string>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/internal/optional.hpp>
+#include <valijson/exceptions.hpp>
+
+#ifdef _MSC_VER
+#pragma warning( push )
+#pragma warning( disable : 4702 )
+#endif
+
+namespace valijson {
+namespace internal {
+namespace json_pointer {
+
+/**
+ * @brief   Replace all occurrences of `search` with `replace`. Modifies `subject` in place.
+ *
+ * @param   subject  string to operate on
+ * @param   search   string to search
+ * @param   replace  replacement string
+ */
+inline void replaceAllInPlace(std::string& subject, const char* search,
+                                const char* replace)
+{
+    size_t pos = 0;
+
+    while((pos = subject.find(search, pos)) != std::string::npos) {
+        subject.replace(pos, strlen(search), replace);
+        pos += strlen(replace);
+    }
+}
+
+/**
+ * @brief   Return the char value corresponding to a 2-digit hexadecimal string
+ *
+ * @throws  std::runtime_error for strings that are not exactly two characters
+ *          in length and for strings that contain non-hexadecimal characters
+ *
+ * @return  decoded char value corresponding to the hexadecimal string
+ */
+inline char decodePercentEncodedChar(const std::string &digits)
+{
+    if (digits.length() != 2) {
+        throwRuntimeError("Failed to decode %-encoded character '" +
+                digits + "' due to unexpected number of characters; "
+                "expected two characters");
+    }
+
+    errno = 0;
+    const char *begin = digits.c_str();
+    char *end = nullptr;
+    const unsigned long value = strtoul(begin, &end, 16);
+    if (end != begin && *end != '\0') {
+        throwRuntimeError("Failed to decode %-encoded character '" +
+                digits + "'");
+    }
+
+    return char(value);
+}
+
+/**
+ * @brief   Extract and transform the token between two iterators
+ *
+ * This function is responsible for extracting a JSON Reference token from
+ * between two iterators, and performing any necessary transformations, before
+ * returning the resulting string. Its main purpose is to replace the escaped
+ * character sequences defined in the RFC-6901 (JSON Pointer), and to decode
+ * %-encoded character sequences defined in RFC-3986 (URI).
+ *
+ * The encoding used in RFC-3986 should be familiar to many developers, but
+ * the escaped character sequences used in JSON Pointers may be less so. From
+ * the JSON Pointer specification (RFC 6901, April 2013):
+ *
+ *    Evaluation of each reference token begins by decoding any escaped
+ *    character sequence.  This is performed by first transforming any
+ *    occurrence of the sequence '~1' to '/', and then transforming any
+ *    occurrence of the sequence '~0' to '~'.  By performing the
+ *    substitutions in this order, an implementation avoids the error of
+ *    turning '~01' first into '~1' and then into '/', which would be
+ *    incorrect (the string '~01' correctly becomes '~1' after
+ *    transformation).
+ *
+ * @param   begin  iterator pointing to beginning of a token
+ * @param   end    iterator pointing to one character past the end of the token
+ *
+ * @return  string with escaped character sequences replaced
+ *
+ */
+inline std::string extractReferenceToken(std::string::const_iterator begin,
+        std::string::const_iterator end)
+{
+    std::string token(begin, end);
+
+    // Replace JSON Pointer-specific escaped character sequences
+    replaceAllInPlace(token, "~1", "/");
+    replaceAllInPlace(token, "~0", "~");
+
+    // Replace %-encoded character sequences with their actual characters
+    for (size_t n = token.find('%'); n != std::string::npos;
+            n = token.find('%', n + 1)) {
+
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            const char c = decodePercentEncodedChar(token.substr(n + 1, 2));
+            token.replace(n, 3, &c, 1);
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (const std::runtime_error &e) {
+            throwRuntimeError(
+                    std::string(e.what()) + "; in token: " + token);
+        }
+#endif
+    }
+
+    return token;
+}
+
+/**
+ * @brief   Recursively locate the value referenced by a JSON Pointer
+ *
+ * This function takes both a string reference and an iterator to the beginning
+ * of the substring that is being resolved. This iterator is expected to point
+ * to the beginning of a reference token, whose length will be determined by
+ * searching for the next delimiter ('/' or '\0'). A reference token must be
+ * at least one character in length to be considered valid.
+ *
+ * Once the next reference token has been identified, it will be used either as
+ * an array index or as an the name an object member. The validity of a
+ * reference token depends on the type of the node currently being traversed,
+ * and the applicability of the token to that node. For example, an array can
+ * only be dereferenced by a non-negative integral index.
+ *
+ * Once the next node has been identified, the length of the remaining portion
+ * of the JSON Pointer will be used to determine whether recursion should
+ * terminate.
+ *
+ * @param   node            current node in recursive evaluation of JSON Pointer
+ * @param   jsonPointer     string containing complete JSON Pointer
+ * @param   jsonPointerItr  string iterator pointing the beginning of the next
+ *                          reference token
+ *
+ * @return  an instance of AdapterType that wraps the dereferenced node
+ */
+template<typename AdapterType>
+inline AdapterType resolveJsonPointer(
+        const AdapterType &node,
+        const std::string &jsonPointer,
+        const std::string::const_iterator jsonPointerItr)
+{
+    // TODO: This function will probably need to implement support for
+    // fetching documents referenced by JSON Pointers, similar to the
+    // populateSchema function.
+
+    const std::string::const_iterator jsonPointerEnd = jsonPointer.end();
+
+    // Terminate recursion if all reference tokens have been consumed
+    if (jsonPointerItr == jsonPointerEnd) {
+        return node;
+    }
+
+    // Reference tokens must begin with a leading slash
+    if (*jsonPointerItr != '/') {
+        throwRuntimeError("Expected reference token to begin with "
+                "leading slash; remaining tokens: " +
+                std::string(jsonPointerItr, jsonPointerEnd));
+    }
+
+    // Find iterator that points to next slash or newline character; this is
+    // one character past the end of the current reference token
+    std::string::const_iterator jsonPointerNext =
+            std::find(jsonPointerItr + 1, jsonPointerEnd, '/');
+
+    // Extract the next reference token
+    const std::string referenceToken = extractReferenceToken(
+            jsonPointerItr + 1, jsonPointerNext);
+
+    // Empty reference tokens should be ignored
+    if (referenceToken.empty()) {
+        return resolveJsonPointer(node, jsonPointer, jsonPointerNext);
+
+    } else if (node.isArray()) {
+        if (referenceToken == "-") {
+            throwRuntimeError("Hyphens cannot be used as array indices "
+                    "since the requested array element does not yet exist");
+        }
+
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            // Fragment must be non-negative integer
+            const uint64_t index = std::stoul(referenceToken);
+            typedef typename AdapterType::Array Array;
+            const Array arr = node.asArray();
+            typename Array::const_iterator itr = arr.begin();
+            const uint64_t arrSize = arr.size();
+
+            if (arrSize == 0 || index > arrSize - 1) {
+                throwRuntimeError("Expected reference token to identify "
+                        "an element in the current array, but array index is "
+                        "out of bounds; actual token: " + referenceToken);
+            }
+
+            if (index > static_cast<uint64_t>(std::numeric_limits<std::ptrdiff_t>::max())) {
+                throwRuntimeError("Array index out of bounds; hard "
+                        "limit is " + std::to_string(
+                                std::numeric_limits<std::ptrdiff_t>::max()));
+            }
+
+            itr.advance(static_cast<std::ptrdiff_t>(index));
+
+            // Recursively process the remaining tokens
+            return resolveJsonPointer(*itr, jsonPointer, jsonPointerNext);
+
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (std::invalid_argument &) {
+            throwRuntimeError("Expected reference token to contain a "
+                    "non-negative integer to identify an element in the "
+                    "current array; actual token: " + referenceToken);
+        }
+#endif
+    } else if (node.maybeObject()) {
+        // Fragment must identify a member of the candidate object
+        typedef typename AdapterType::Object Object;
+
+        const Object object = node.asObject();
+        typename Object::const_iterator itr = object.find(
+                referenceToken);
+        if (itr == object.end()) {
+            throwRuntimeError("Expected reference token to identify an "
+                    "element in the current object; "
+                    "actual token: " + referenceToken);
+            abort();
+        }
+
+        // Recursively process the remaining tokens
+        return resolveJsonPointer(itr->second, jsonPointer, jsonPointerNext);
+    }
+
+    throwRuntimeError("Expected end of JSON Pointer, but at least "
+            "one reference token has not been processed; remaining tokens: " +
+            std::string(jsonPointerNext, jsonPointerEnd));
+    abort();
+}
+
+/**
+ * @brief   Return the JSON Value referenced by a JSON Pointer
+ *
+ * @param   rootNode     node to use as root for JSON Pointer resolution
+ * @param   jsonPointer  string containing JSON Pointer
+ *
+ * @return  an instance AdapterType in the specified document
+ */
+template<typename AdapterType>
+inline AdapterType resolveJsonPointer(
+        const AdapterType &rootNode,
+        const std::string &jsonPointer)
+{
+    return resolveJsonPointer(rootNode, jsonPointer, jsonPointer.begin());
+}
+
+} // namespace json_pointer
+} // namespace internal
+} // namespace valijson
+
+#ifdef _MSC_VER
+#pragma warning( pop )
+#endif
diff --git a/subprojects/valijson/include/valijson/internal/json_reference.hpp b/subprojects/valijson/include/valijson/internal/json_reference.hpp
new file mode 100644
index 000000000..fc67a3477
--- /dev/null
+++ b/subprojects/valijson/include/valijson/internal/json_reference.hpp
@@ -0,0 +1,60 @@
+#pragma once
+
+#include <stdexcept>
+#include <string>
+
+#include <valijson/internal/optional.hpp>
+
+namespace valijson {
+namespace internal {
+namespace json_reference {
+
+/**
+  * @brief   Extract URI from JSON Reference relative to the current schema
+  *
+  * @param   jsonRef  JSON Reference to extract from
+  * @param   schema   Schema that JSON Reference URI is relative to
+  *
+  * @return  Optional string containing URI
+  */
+inline opt::optional<std::string> getJsonReferenceUri(
+    const std::string &jsonRef)
+{
+    const size_t ptrPos = jsonRef.find('#');
+    if (ptrPos == 0) {
+        // The JSON Reference does not contain a URI, but might contain a
+        // JSON Pointer that refers to the current document
+        return opt::optional<std::string>();
+    } else if (ptrPos != std::string::npos) {
+        // The JSON Reference contains a URI and possibly a JSON Pointer
+        return jsonRef.substr(0, ptrPos);
+    }
+
+    // The entire JSON Reference should be treated as a URI
+    return jsonRef;
+}
+
+/**
+  * @brief   Extract JSON Pointer portion of a JSON Reference
+  *
+  * @param   jsonRef  JSON Reference to extract from
+  *
+  * @return  Optional string containing JSON Pointer
+  */
+inline opt::optional<std::string> getJsonReferencePointer(
+    const std::string &jsonRef)
+{
+    // Attempt to extract JSON Pointer if '#' character is present. Note
+    // that a valid pointer would contain at least a leading forward
+    // slash character.
+    const size_t ptrPos = jsonRef.find('#');
+    if (ptrPos != std::string::npos) {
+        return jsonRef.substr(ptrPos + 1);
+    }
+
+    return opt::optional<std::string>();
+}
+
+} // namespace json_reference
+} // namespace internal
+} // namespace valijson
diff --git a/subprojects/valijson/include/valijson/internal/optional.hpp b/subprojects/valijson/include/valijson/internal/optional.hpp
new file mode 100644
index 000000000..c9bc47b61
--- /dev/null
+++ b/subprojects/valijson/include/valijson/internal/optional.hpp
@@ -0,0 +1,14 @@
+#pragma once
+
+#if __cplusplus >= 201703
+// Visual C++ only supports __has_include in versions 14.12 and greater
+#  if !defined(_MSC_VER) || _MSC_VER >= 1912
+#    if __has_include(<optional>)
+#      include <optional>
+namespace opt = std;
+#    endif
+#  endif
+#else
+#  include <compat/optional.hpp>
+namespace opt = std::experimental;
+#endif
diff --git a/subprojects/valijson/include/valijson/internal/uri.hpp b/subprojects/valijson/include/valijson/internal/uri.hpp
new file mode 100644
index 000000000..d04a18b18
--- /dev/null
+++ b/subprojects/valijson/include/valijson/internal/uri.hpp
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <string>
+
+namespace valijson {
+namespace internal {
+namespace uri {
+
+/**
+  * @brief  Placeholder function to check whether a URI is absolute
+  *
+  * This function just checks for '://'
+  */
+inline bool isUriAbsolute(const std::string &documentUri)
+{
+    static const char * placeholderMarker = "://";
+
+    return documentUri.find(placeholderMarker) != std::string::npos;
+}
+
+/**
+  * Placeholder function to resolve a relative URI within a given scope
+  */
+inline std::string resolveRelativeUri(
+        const std::string &resolutionScope,
+        const std::string &relativeUri)
+{
+    return resolutionScope + relativeUri;
+}
+
+} // namespace uri
+} // namespace internal
+} // namespace valijson
diff --git a/subprojects/valijson/include/valijson/schema.hpp b/subprojects/valijson/include/valijson/schema.hpp
new file mode 100644
index 000000000..a3c3f24e4
--- /dev/null
+++ b/subprojects/valijson/include/valijson/schema.hpp
@@ -0,0 +1,224 @@
+#pragma once
+
+#include <cstdio>
+#include <set>
+
+#include <valijson/subschema.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+
+/**
+ * Represents the root of a JSON Schema
+ *
+ * The root is distinct from other sub-schemas because it is the canonical
+ * starting point for validation of a document against a given a JSON Schema.
+ */
+class Schema: public Subschema
+{
+public:
+    /**
+     * @brief  Construct a new Schema instance with no constraints
+     */
+    Schema()
+      : sharedEmptySubschema(newSubschema()) { }
+
+    /**
+     * @brief  Construct a new Schema using custom memory management
+     *         functions
+     *
+     * @param  allocFn  malloc- or new-like function to allocate memory
+     *                  within Schema, such as for Subschema instances
+     * @param  freeFn   free-like function to free memory allocated with
+     *                  the `customAlloc` function
+     */
+    Schema(CustomAlloc allocFn, CustomFree freeFn)
+      : Subschema(allocFn, freeFn),
+        sharedEmptySubschema(newSubschema()) { }
+
+    // Disable copy construction
+    Schema(const Schema &) = delete;
+
+    // Disable copy assignment
+    Schema & operator=(const Schema &) = delete;
+
+    /**
+     * @brief  Clean up and free all memory managed by the Schema
+     *
+     * Note that any Subschema pointers created and returned by this Schema
+     * should be considered invalid.
+     */
+    ~Schema() override
+    {
+        sharedEmptySubschema->~Subschema();
+        m_freeFn(const_cast<Subschema *>(sharedEmptySubschema));
+        sharedEmptySubschema = nullptr;
+
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            for (auto subschema : subschemaSet) {
+                subschema->~Subschema();
+                m_freeFn(subschema);
+            }
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (const std::exception &e) {
+            fprintf(stderr, "Caught an exception while destroying Schema: %s",
+                    e.what());
+        }
+#endif
+    }
+
+    /**
+     * @brief  Copy a constraint to a specific sub-schema
+     *
+     * @param  constraint  reference to a constraint that will be copied into
+     *                     the sub-schema
+     * @param  subschema   pointer to the sub-schema that will own the copied
+     *                     constraint
+     *
+     * @throws std::runtime_error if the sub-schema is not owned by this Schema
+     *         instance
+     */
+    void addConstraintToSubschema(const Constraint &constraint,
+            const Subschema *subschema)
+    {
+        // TODO: Check heirarchy for subschemas that do not belong...
+
+        mutableSubschema(subschema)->addConstraint(constraint);
+    }
+
+    /**
+     * @brief  Create a new Subschema instance that is owned by this Schema
+     *
+     * @returns  const pointer to the new Subschema instance
+     */
+    const Subschema * createSubschema()
+    {
+        Subschema *subschema = newSubschema();
+
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            if (!subschemaSet.insert(subschema).second) {
+                throwRuntimeError(
+                        "Failed to store pointer for new sub-schema");
+            }
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (...) {
+            subschema->~Subschema();
+            m_freeFn(subschema);
+            throw;
+        }
+#endif
+        return subschema;
+    }
+
+    /**
+     * @brief  Return a pointer to the shared empty schema
+     */
+    const Subschema * emptySubschema() const
+    {
+        return sharedEmptySubschema;
+    }
+
+    /**
+     * @brief  Get a pointer to the root sub-schema of this Schema instance
+     */
+    const Subschema * root() const
+    {
+        return this;
+    }
+
+    void setAlwaysInvalid(const Subschema *subschema, bool value)
+    {
+        mutableSubschema(subschema)->setAlwaysInvalid(value);
+    }
+
+    /**
+     * @brief  Update the description for one of the sub-schemas owned by this
+     *         Schema instance
+     *
+     * @param  subschema    sub-schema to update
+     * @param  description  new description
+     */
+    void setSubschemaDescription(const Subschema *subschema,
+            const std::string &description)
+    {
+        mutableSubschema(subschema)->setDescription(description);
+    }
+
+    /**
+     * @brief  Update the ID for one of the sub-schemas owned by this Schema
+     *         instance
+     *
+     * @param  subschema  sub-schema to update
+     * @param  id         new ID
+     */
+    void setSubschemaId(const Subschema *subschema, const std::string &id)
+    {
+        mutableSubschema(subschema)->setId(id);
+    }
+
+    /**
+     * @brief  Update the title for one of the sub-schemas owned by this Schema
+     *         instance
+     *
+     * @param  subschema  sub-schema to update
+     * @param  title      new title
+     */
+    void setSubschemaTitle(const Subschema *subschema, const std::string &title)
+    {
+        mutableSubschema(subschema)->setTitle(title);
+    }
+
+private:
+
+    Subschema *newSubschema()
+    {
+        void *ptr = m_allocFn(sizeof(Subschema));
+        if (!ptr) {
+            throwRuntimeError(
+                    "Failed to allocate memory for shared empty sub-schema");
+        }
+
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            return new (ptr) Subschema();
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (...) {
+            m_freeFn(ptr);
+            throw;
+        }
+#endif
+    }
+
+    Subschema * mutableSubschema(const Subschema *subschema)
+    {
+        if (subschema == this) {
+            return this;
+        }
+
+        if (subschema == sharedEmptySubschema) {
+            throwRuntimeError(
+                    "Cannot modify the shared empty sub-schema");
+        }
+
+        auto *noConst = const_cast<Subschema*>(subschema);
+        if (subschemaSet.find(noConst) == subschemaSet.end()) {
+            throwRuntimeError(
+                    "Subschema pointer is not owned by this Schema instance");
+        }
+
+        return noConst;
+    }
+
+    /// Set of Subschema instances owned by this schema
+    std::set<Subschema*> subschemaSet;
+
+    /// Empty schema that can be reused by multiple constraints
+    const Subschema *sharedEmptySubschema;
+};
+
+} // namespace valijson
diff --git a/subprojects/valijson/include/valijson/schema_parser.hpp b/subprojects/valijson/include/valijson/schema_parser.hpp
new file mode 100644
index 000000000..908cd182e
--- /dev/null
+++ b/subprojects/valijson/include/valijson/schema_parser.hpp
@@ -0,0 +1,2282 @@
+#pragma once
+
+#include <stdexcept>
+#include <iostream>
+#include <vector>
+#include <memory>
+#include <functional>
+
+#include <valijson/adapters/adapter.hpp>
+#include <valijson/constraints/concrete_constraints.hpp>
+#include <valijson/internal/debug.hpp>
+#include <valijson/internal/json_pointer.hpp>
+#include <valijson/internal/json_reference.hpp>
+#include <valijson/internal/uri.hpp>
+#include <valijson/constraint_builder.hpp>
+#include <valijson/schema.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+
+/**
+ * @brief  Parser for populating a Schema based on a JSON Schema document.
+ *
+ * The SchemaParser class supports Drafts 3 and 4 of JSON Schema, however
+ * Draft 3 support should be considered deprecated.
+ *
+ * The functions provided by this class have been templated so that they can
+ * be used with different Adapter types.
+ */
+class SchemaParser
+{
+public:
+    /// Supported versions of JSON Schema
+    enum Version {
+        kDraft3,      ///< @deprecated JSON Schema v3 has been superseded by v4
+        kDraft4,
+        kDraft7
+    };
+
+    /**
+     * @brief  Construct a new SchemaParser for a given version of JSON Schema
+     *
+     * @param  version  Version of JSON Schema that will be expected
+     */
+    explicit SchemaParser(const Version version = kDraft7)
+      : m_version(version) { }
+
+    /**
+     * @brief  Release memory associated with custom ConstraintBuilders
+     */
+    virtual ~SchemaParser()
+    {
+        for (const auto& entry : constraintBuilders) {
+            delete entry.second;
+        }
+    }
+
+    /**
+     * @brief  Struct to contain templated function type for fetching documents
+     */
+    template<typename AdapterType>
+    struct FunctionPtrs
+    {
+        typedef typename adapters::AdapterTraits<AdapterType>::DocumentType DocumentType;
+
+        /// Templated function pointer type for fetching remote documents
+        typedef std::function<const DocumentType* (const std::string &uri)> FetchDoc;
+
+        /// Templated function pointer type for freeing fetched documents
+        typedef std::function<void (const DocumentType *)> FreeDoc;
+    };
+
+    /**
+     * @brief  Add a custom contraint to this SchemaParser
+
+     * @param  key      name that will be used to identify relevant constraints
+     *                  while parsing a schema document
+     * @param  builder  pointer to a subclass of ConstraintBuilder that can
+     *                  parse custom constraints found in a schema document,
+     *                  and return an appropriate instance of Constraint; this
+     *                  class guarantees that it will take ownership of this
+     *                  pointer - unless this function throws an exception
+     *
+     * @todo   consider accepting a list of custom ConstraintBuilders in
+     *         constructor, so that this class remains immutable after
+     *         construction
+     *
+     * @todo   Add additional checks for key conflicts, empty keys, and
+     *         potential restrictions relating to case sensitivity
+     */
+    void addConstraintBuilder(const std::string &key, const ConstraintBuilder *builder)
+    {
+        constraintBuilders.push_back(std::make_pair(key, builder));
+    }
+
+    /**
+     * @brief  Populate a Schema object from JSON Schema document
+     *
+     * When processing Draft 3 schemas, the parentSubschema and ownName pointers
+     * should be set in contexts where a 'required' constraint would be valid.
+     * These are used to add a RequiredConstraint object to the Schema that
+     * contains the required property.
+     *
+     * @param  node          Reference to node to parse
+     * @param  schema        Reference to Schema to populate
+     * @param  fetchDoc      Function to fetch remote JSON documents (optional)
+     */
+    template<typename AdapterType>
+    void populateSchema(
+        const AdapterType &node,
+        Schema &schema,
+        typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc = nullptr ,
+        typename FunctionPtrs<AdapterType>::FreeDoc freeDoc = nullptr )
+    {
+        if ((fetchDoc == nullptr ) ^ (freeDoc == nullptr)) {
+            throwRuntimeError("Remote document fetching can't be enabled without both fetch and free functions");
+        }
+
+        typename DocumentCache<AdapterType>::Type docCache;
+        SchemaCache schemaCache;
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            resolveThenPopulateSchema(schema, node, node, schema, opt::optional<std::string>(), "", fetchDoc, nullptr,
+                    nullptr, docCache, schemaCache);
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (...) {
+            freeDocumentCache<AdapterType>(docCache, freeDoc);
+            throw;
+        }
+#endif
+
+        freeDocumentCache<AdapterType>(docCache, freeDoc);
+    }
+
+private:
+
+    typedef std::vector<std::pair<std::string, const ConstraintBuilder *>>
+        ConstraintBuilders;
+
+    ConstraintBuilders constraintBuilders;
+
+    template<typename AdapterType>
+    struct DocumentCache
+    {
+        typedef typename adapters::AdapterTraits<AdapterType>::DocumentType DocumentType;
+
+        typedef std::map<std::string, const DocumentType*> Type;
+    };
+
+    typedef std::map<std::string, const Subschema *> SchemaCache;
+
+    /**
+     * @brief  Free memory used by fetched documents
+     *
+     * If a custom 'free' function has not been provided, then the default
+     * delete operator will be used.
+     *
+     * @param  docCache  collection of fetched documents to free
+     * @param  freeDoc   optional custom free function
+     */
+    template<typename AdapterType>
+    void freeDocumentCache(const typename DocumentCache<AdapterType>::Type
+            &docCache, typename FunctionPtrs<AdapterType>::FreeDoc freeDoc)
+    {
+        typedef typename DocumentCache<AdapterType>::Type DocCacheType;
+
+        for (const typename DocCacheType::value_type &v : docCache) {
+            freeDoc(v.second);
+        }
+    }
+
+    /**
+     * @brief  Find the absolute URI for a document, within a resolution scope
+     *
+     * This function captures five different cases that can occur when
+     * attempting to resolve a document URI within a particular resolution
+     * scope:
+     *
+     *  - resolution scope not present, but absolute document URI is
+     *       => document URI as-is
+     *  - resolution scope not present, and document URI is relative or absent
+     *       => no result
+     *  - resolution scope is present, and document URI is a relative path
+     *       => resolve document URI relative to resolution scope
+     *  - resolution scope is present, and document URI is absolute
+     *       => document URI as-is
+     *  - resolution scope is present, but document URI is not
+     *       => resolution scope as-is
+     *
+     * This function assumes that the resolution scope is absolute.
+     *
+     * When resolving a document URI relative to the resolution scope, the
+     * document URI should be used to replace the path, query and fragment
+     * portions of URI provided by the resolution scope.
+     */
+    virtual opt::optional<std::string> findAbsoluteDocumentUri(
+            const opt::optional<std::string>& resolutionScope,
+            const opt::optional<std::string>& documentUri)
+    {
+        if (resolutionScope) {
+            if (documentUri) {
+                if (internal::uri::isUriAbsolute(*documentUri)) {
+                    return *documentUri;
+                } else {
+                    return internal::uri::resolveRelativeUri(*resolutionScope, *documentUri);
+                }
+            } else {
+                return *resolutionScope;
+            }
+        } else if (documentUri && internal::uri::isUriAbsolute(*documentUri)) {
+            return *documentUri;
+        } else {
+            return opt::optional<std::string>();
+        }
+    }
+
+    /**
+     * @brief  Extract a JSON Reference string from a node
+     *
+     * @param  node    node to extract the JSON Reference from
+     * @param  result  reference to string to set with the result
+     *
+     * @throws std::invalid_argument if node is an object containing a `$ref`
+     *         property but with a value that cannot be interpreted as a string
+     *
+     * @return \c true if a JSON Reference was extracted; \c false otherwise
+     */
+    template<typename AdapterType>
+    bool extractJsonReference(const AdapterType &node, std::string &result)
+    {
+        if (!node.isObject()) {
+            return false;
+        }
+
+        const typename AdapterType::Object o = node.getObject();
+        const typename AdapterType::Object::const_iterator itr = o.find("$ref");
+        if (itr == o.end()) {
+            return false;
+        } else if (!itr->second.getString(result)) {
+            throwRuntimeError("$ref property expected to contain string value.");
+        }
+
+        return true;
+    }
+
+    /**
+     * Sanitise an optional JSON Pointer, trimming trailing slashes
+     */
+    static std::string sanitiseJsonPointer(const opt::optional<std::string>& input)
+    {
+        if (input) {
+            // Trim trailing slash(es)
+            std::string sanitised = *input;
+            sanitised.erase(sanitised.find_last_not_of('/') + 1,
+                    std::string::npos);
+
+            return sanitised;
+        }
+
+        // If the JSON Pointer is not set, assume that the URI points to
+        // the root of the document
+        return "";
+    }
+
+    /**
+     * @brief  Search the schema cache for a schema matching a given key
+     *
+     * If the key is not present in the query cache, a nullptr will be
+     * returned, and the contents of the cache will remain unchanged. This is
+     * in contrast to the behaviour of the std::map [] operator, which would
+     * add the nullptr to the cache.
+     *
+     * @param  schemaCache  schema cache to query
+     * @param  queryKey     key to search for
+     *
+     * @return shared pointer to Schema if found, nullptr otherwise
+     */
+    static const Subschema * querySchemaCache(SchemaCache &schemaCache,
+            const std::string &queryKey)
+    {
+        const SchemaCache::iterator itr = schemaCache.find(queryKey);
+        if (itr == schemaCache.end()) {
+            return nullptr;
+        }
+
+        return itr->second;
+    }
+
+    /**
+     * @brief  Add entries to the schema cache for a given list of keys
+     *
+     * @param  schemaCache   schema cache to update
+     * @param  keysToCreate  list of keys to create entries for
+     * @param  schema        shared pointer to schema that keys will map to
+     *
+     * @throws std::logic_error if any of the keys are already present in the
+     *         schema cache. This behaviour is intended to help detect incorrect
+     *         usage of the schema cache during development, and is not expected
+     *         to occur otherwise, even for malformed schemas.
+     */
+    static void updateSchemaCache(SchemaCache &schemaCache,
+            const std::vector<std::string> &keysToCreate,
+            const Subschema *schema)
+    {
+        for (const std::string &keyToCreate : keysToCreate) {
+            const SchemaCache::value_type value(keyToCreate, schema);
+            if (!schemaCache.insert(value).second) {
+                throwLogicError("Key '" + keyToCreate + "' already in schema cache.");
+            }
+        }
+    }
+
+    /**
+     * @brief  Recursive helper function for retrieving or creating schemas
+     *
+     * This function will be applied recursively until a concrete node is found.
+     * A concrete node is a node that contains actual schema constraints rather
+     * than a JSON Reference.
+     *
+     * This termination condition may be trigged by visiting the concrete node
+     * at the end of a series of $ref nodes, or by finding a schema for one of
+     * those $ref nodes in the schema cache. An entry will be added to the
+     * schema cache for each node visited on the path to the concrete node.
+     *
+     * @param  rootSchema    The Schema instance, and root subschema, through
+     *                       which other subschemas can be created and
+     *                       modified
+     * @param  rootNode      Reference to the node from which JSON References
+     *                       will be resolved when they refer to the current
+     *                       document
+     * @param  node          Reference to the node to parse
+     * @param  currentScope  URI for current resolution scope
+     * @param  nodePath      JSON Pointer representing path to current node
+     * @param  fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param  parentSchema  Optional pointer to the parent schema, used to
+     *                       support required keyword in Draft 3
+     * @param  ownName       Optional pointer to a node name, used to support
+     *                       the 'required' keyword in Draft 3
+     * @param  docCache      Cache of resolved and fetched remote documents
+     * @param  schemaCache   Cache of populated schemas
+     * @param  newCacheKeys  A list of keys that should be added to the cache
+     *                       when recursion terminates
+     */
+    template<typename AdapterType>
+    const Subschema * makeOrReuseSchema(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        const Subschema *parentSubschema,
+        const std::string *ownName,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache,
+        std::vector<std::string> &newCacheKeys)
+    {
+        std::string jsonRef;
+
+        // Check for the first termination condition (found a non-$ref node)
+        if (!extractJsonReference(node, jsonRef)) {
+
+            // Construct a key that we can use to search the schema cache for
+            // a schema corresponding to the current node
+            const std::string schemaCacheKey = currentScope ? (*currentScope + nodePath) : nodePath;
+
+            // Retrieve an existing schema from the cache if possible
+            const Subschema *cachedPtr = querySchemaCache(schemaCache, schemaCacheKey);
+
+            // Create a new schema otherwise
+            const Subschema *subschema = cachedPtr ? cachedPtr : rootSchema.createSubschema();
+
+            // Add cache entries for keys belonging to any $ref nodes that were
+            // visited before arriving at the current node
+            updateSchemaCache(schemaCache, newCacheKeys, subschema);
+
+            // Schema cache did not contain a pre-existing schema corresponding
+            // to the current node, so the schema that was returned will need
+            // to be populated
+            if (!cachedPtr) {
+                populateSchema(rootSchema, rootNode, node, *subschema,
+                        currentScope, nodePath, fetchDoc, parentSubschema,
+                        ownName, docCache, schemaCache);
+            }
+
+            return subschema;
+        }
+
+        // Returns a document URI if the reference points somewhere
+        // other than the current document
+        const opt::optional<std::string> documentUri = internal::json_reference::getJsonReferenceUri(jsonRef);
+
+        // Extract JSON Pointer from JSON Reference, with any trailing
+        // slashes removed so that keys in the schema cache end
+        // consistently
+        const std::string actualJsonPointer = sanitiseJsonPointer(
+                internal::json_reference::getJsonReferencePointer(jsonRef));
+
+        // Determine the actual document URI based on the resolution
+        // scope. An absolute document URI will take precedence when
+        // present, otherwise we need to resolve the URI relative to
+        // the current resolution scope
+        const opt::optional<std::string> actualDocumentUri = findAbsoluteDocumentUri(currentScope, documentUri);
+
+        // Construct a key to search the schema cache for an existing schema
+        const std::string queryKey = actualDocumentUri ? (*actualDocumentUri + actualJsonPointer) : actualJsonPointer;
+
+        // Check for the second termination condition (found a $ref node that
+        // already has an entry in the schema cache)
+        const Subschema *cachedPtr = querySchemaCache(schemaCache, queryKey);
+        if (cachedPtr) {
+            updateSchemaCache(schemaCache, newCacheKeys, cachedPtr);
+            return cachedPtr;
+        }
+
+        if (actualDocumentUri && (!currentScope || *actualDocumentUri != *currentScope)) {
+            const typename FunctionPtrs<AdapterType>::DocumentType *newDoc = nullptr;
+
+            // Have we seen this document before?
+            typename DocumentCache<AdapterType>::Type::iterator docCacheItr =
+                    docCache.find(*actualDocumentUri);
+            if (docCacheItr == docCache.end()) {
+                // Resolve reference against remote document
+                if (!fetchDoc) {
+                    throwRuntimeError("Fetching of remote JSON References not enabled.");
+                }
+
+                // Returns a pointer to the remote document that was
+                // retrieved, or null if retrieval failed. This class
+                // will take ownership of the pointer, and call freeDoc
+                // when it is no longer needed.
+                newDoc = fetchDoc(*actualDocumentUri);
+
+                // Can't proceed without the remote document
+                if (!newDoc) {
+                    throwRuntimeError("Failed to fetch referenced schema document: " + *actualDocumentUri);
+                }
+
+                typedef typename DocumentCache<AdapterType>::Type::value_type
+                        DocCacheValueType;
+
+                docCache.insert(DocCacheValueType(*actualDocumentUri, newDoc));
+
+            } else {
+                newDoc = docCacheItr->second;
+            }
+
+            const AdapterType newRootNode(*newDoc);
+
+            // Find where we need to be in the document
+            const AdapterType &referencedAdapter =
+                    internal::json_pointer::resolveJsonPointer(newRootNode,
+                            actualJsonPointer);
+
+            newCacheKeys.push_back(queryKey);
+
+            // Populate the schema, starting from the referenced node, with
+            // nested JSON References resolved relative to the new root node
+            return makeOrReuseSchema(rootSchema, newRootNode, referencedAdapter,
+                    currentScope, actualJsonPointer, fetchDoc, parentSubschema,
+                    ownName, docCache, schemaCache, newCacheKeys);
+
+        }
+
+        // JSON References in nested schema will be resolved relative to the
+        // current document
+        const AdapterType &referencedAdapter =
+                internal::json_pointer::resolveJsonPointer(
+                        rootNode, actualJsonPointer);
+
+        newCacheKeys.push_back(queryKey);
+
+        // Populate the schema, starting from the referenced node, with
+        // nested JSON References resolved relative to the new root node
+        return makeOrReuseSchema(rootSchema, rootNode, referencedAdapter,
+                currentScope, actualJsonPointer, fetchDoc, parentSubschema,
+                ownName, docCache, schemaCache, newCacheKeys);
+    }
+
+    /**
+     * @brief  Return pointer for the schema corresponding to a given node
+     *
+     * This function makes use of a schema cache, so that if the path to the
+     * current node is the same as one that has already been parsed and
+     * populated, a pointer to the existing Subschema will be returned.
+     *
+     * Should a series of $ref, or reference, nodes be resolved before reaching
+     * a concrete node, an entry will be added to the schema cache for each of
+     * the nodes in that path.
+     *
+     * @param  rootSchema    The Schema instance, and root subschema, through
+     *                       which other subschemas can be created and
+     *                       modified
+     * @param  rootNode      Reference to the node from which JSON References
+     *                       will be resolved when they refer to the current
+     *                       document
+     * @param  node          Reference to the node to parse
+     * @param  currentScope  URI for current resolution scope
+     * @param  nodePath      JSON Pointer representing path to current node
+     * @param  fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param  parentSchema  Optional pointer to the parent schema, used to
+     *                       support required keyword in Draft 3
+     * @param  ownName       Optional pointer to a node name, used to support
+     *                       the 'required' keyword in Draft 3
+     * @param  docCache      Cache of resolved and fetched remote documents
+     * @param  schemaCache   Cache of populated schemas
+     */
+    template<typename AdapterType>
+    const Subschema * makeOrReuseSchema(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        const Subschema *parentSubschema,
+        const std::string *ownName,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        std::vector<std::string> schemaCacheKeysToCreate;
+
+        return makeOrReuseSchema(rootSchema, rootNode, node, currentScope,
+                nodePath, fetchDoc, parentSubschema, ownName, docCache,
+                schemaCache, schemaCacheKeysToCreate);
+    }
+
+    /**
+     * @brief  Populate a Schema object from JSON Schema document
+     *
+     * When processing Draft 3 schemas, the parentSubschema and ownName pointers
+     * should be set in contexts where a 'required' constraint would be valid.
+     * These are used to add a RequiredConstraint object to the Schema that
+     * contains the required property.
+     *
+     * @param  rootSchema       The Schema instance, and root subschema, through
+     *                          which other subschemas can be created and
+     *                          modified
+     * @param  rootNode         Reference to the node from which JSON References
+     *                          will be resolved when they refer to the current
+     *                          document
+     * @param  node             Reference to node to parse
+     * @param  schema           Reference to Schema to populate
+     * @param  currentScope     URI for current resolution scope
+     * @param  nodePath         JSON Pointer representing path to current node
+     * @param  fetchDoc         Optional function to fetch remote JSON documents
+     * @param  parentSubschema  Optional pointer to the parent schema, used to
+     *                          support required keyword in Draft 3
+     * @param  ownName          Optional pointer to a node name, used to support
+     *                          the 'required' keyword in Draft 3
+     * @param  docCache         Cache of resolved and fetched remote documents
+     * @param  schemaCache      Cache of populated schemas
+     */
+    template<typename AdapterType>
+    void populateSchema(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const Subschema &subschema,
+        const opt::optional<std::string>& currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        const Subschema *parentSubschema,
+        const std::string *ownName,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        static_assert((std::is_convertible<AdapterType,
+            const valijson::adapters::Adapter &>::value),
+            "SchemaParser::populateSchema must be invoked with an "
+            "appropriate Adapter implementation");
+
+        if (!node.isObject()) {
+            if (m_version == kDraft7 && node.maybeBool()) {
+                // Boolean schema
+                if (!node.asBool()) {
+                    rootSchema.setAlwaysInvalid(&subschema, true);
+                }
+                return;
+            } else {
+                std::string s;
+                s += "Expected node at ";
+                s += nodePath;
+                if (m_version == kDraft7) {
+                    s += " to contain schema object or boolean value; actual node type is: ";
+                } else {
+                    s += " to contain schema object; actual node type is: ";
+                }
+                s += internal::nodeTypeAsString(node);
+                throwRuntimeError(s);
+            }
+        }
+
+        const typename AdapterType::Object object = node.asObject();
+        typename AdapterType::Object::const_iterator itr(object.end());
+
+        // Check for 'id' attribute and update current scope
+        opt::optional<std::string> updatedScope;
+        if ((itr = object.find("id")) != object.end() && itr->second.maybeString()) {
+            const std::string id = itr->second.asString();
+            rootSchema.setSubschemaId(&subschema, itr->second.asString());
+            if (!currentScope || internal::uri::isUriAbsolute(id)) {
+                updatedScope = id;
+            } else {
+                updatedScope = internal::uri::resolveRelativeUri(*currentScope, id);
+            }
+        } else {
+            updatedScope = currentScope;
+        }
+
+        if ((itr = object.find("allOf")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeAllOfConstraint(rootSchema, rootNode, itr->second,
+                            updatedScope, nodePath + "/allOf", fetchDoc,
+                            docCache, schemaCache),
+                    &subschema);
+        }
+
+        if ((itr = object.find("anyOf")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeAnyOfConstraint(rootSchema, rootNode, itr->second,
+                            updatedScope, nodePath + "/anyOf", fetchDoc,
+                            docCache, schemaCache),
+                    &subschema);
+        }
+
+        if ((itr = object.find("const")) != object.end()) {
+            rootSchema.addConstraintToSubschema(makeConstConstraint(itr->second), &subschema);
+        }
+
+        if ((itr = object.find("contains")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeContainsConstraint(rootSchema, rootNode, itr->second,
+                            updatedScope, nodePath + "/contains", fetchDoc,
+                            docCache, schemaCache), &subschema);
+        }
+
+        if ((itr = object.find("dependencies")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeDependenciesConstraint(rootSchema, rootNode,
+                            itr->second, updatedScope,
+                            nodePath + "/dependencies", fetchDoc, docCache,
+                            schemaCache),
+                    &subschema);
+        }
+
+        if ((itr = object.find("description")) != object.end()) {
+            if (itr->second.maybeString()) {
+                rootSchema.setSubschemaDescription(&subschema,
+                        itr->second.asString());
+            } else {
+                throwRuntimeError(
+                        "'description' attribute should have a string value");
+            }
+        }
+
+        if ((itr = object.find("divisibleBy")) != object.end()) {
+            if (m_version == kDraft3) {
+                if (itr->second.maybeInteger()) {
+                    rootSchema.addConstraintToSubschema(
+                            makeMultipleOfIntConstraint(itr->second),
+                            &subschema);
+                } else if (itr->second.maybeDouble()) {
+                    rootSchema.addConstraintToSubschema(
+                            makeMultipleOfDoubleConstraint(itr->second),
+                            &subschema);
+                } else {
+                    throwRuntimeError("Expected an numeric value for "
+                            " 'divisibleBy' constraint.");
+                }
+            } else {
+                throwRuntimeError(
+                        "'divisibleBy' constraint not valid after draft 3");
+            }
+        }
+
+        if ((itr = object.find("enum")) != object.end()) {
+            rootSchema.addConstraintToSubschema(makeEnumConstraint(itr->second), &subschema);
+        }
+
+        {
+            const typename AdapterType::Object::const_iterator itemsItr =
+                    object.find("items");
+
+            if (object.end() != itemsItr) {
+                if (!itemsItr->second.isArray()) {
+                    rootSchema.addConstraintToSubschema(
+                            makeSingularItemsConstraint(rootSchema, rootNode,
+                                    itemsItr->second, updatedScope,
+                                    nodePath + "/items", fetchDoc, docCache,
+                                    schemaCache),
+                            &subschema);
+
+                } else {
+                    const typename AdapterType::Object::const_iterator
+                            additionalItemsItr = object.find("additionalItems");
+                    rootSchema.addConstraintToSubschema(
+                            makeLinearItemsConstraint(rootSchema, rootNode,
+                                    itemsItr != object.end() ? &itemsItr->second : nullptr,
+                                    additionalItemsItr != object.end() ? &additionalItemsItr->second : nullptr,
+                                    updatedScope, nodePath + "/items",
+                                    nodePath + "/additionalItems", fetchDoc,
+                                    docCache, schemaCache),
+                            &subschema);
+                }
+            }
+        }
+
+        {
+            const typename AdapterType::Object::const_iterator ifItr = object.find("if");
+            const typename AdapterType::Object::const_iterator thenItr = object.find("then");
+            const typename AdapterType::Object::const_iterator elseItr = object.find("else");
+
+            if (object.end() != ifItr) {
+                if (m_version == kDraft7) {
+                    rootSchema.addConstraintToSubschema(
+                          makeConditionalConstraint(rootSchema, rootNode,
+                                ifItr->second,
+                                thenItr == object.end() ? nullptr : &thenItr->second,
+                                elseItr == object.end() ? nullptr : &elseItr->second,
+                                updatedScope, nodePath, fetchDoc, docCache, schemaCache),
+                          &subschema);
+                } else {
+                    throwRuntimeError("Not supported");
+                }
+            }
+        }
+
+        if (m_version == kDraft7) {
+            if ((itr = object.find("exclusiveMaximum")) != object.end()) {
+                rootSchema.addConstraintToSubschema(
+                    makeMaximumConstraintExclusive(itr->second),
+                    &subschema);
+            }
+
+            if ((itr = object.find("maximum")) != object.end()) {
+                rootSchema.addConstraintToSubschema(
+                    makeMaximumConstraint<AdapterType>(itr->second, nullptr),
+                    &subschema);
+            }
+        } else if ((itr = object.find("maximum")) != object.end()) {
+            typename AdapterType::Object::const_iterator exclusiveMaximumItr =
+                    object.find("exclusiveMaximum");
+            if (exclusiveMaximumItr == object.end()) {
+                rootSchema.addConstraintToSubschema(
+                        makeMaximumConstraint<AdapterType>(itr->second, nullptr),
+                        &subschema);
+            } else {
+                rootSchema.addConstraintToSubschema(
+                        makeMaximumConstraint(itr->second, &exclusiveMaximumItr->second),
+                        &subschema);
+            }
+        } else if (object.find("exclusiveMaximum") != object.end()) {
+            throwRuntimeError("'exclusiveMaximum' constraint only valid if a 'maximum' "
+                    "constraint is also present");
+        }
+
+        if ((itr = object.find("maxItems")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeMaxItemsConstraint(itr->second), &subschema);
+        }
+
+        if ((itr = object.find("maxLength")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeMaxLengthConstraint(itr->second), &subschema);
+        }
+
+        if ((itr = object.find("maxProperties")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeMaxPropertiesConstraint(itr->second), &subschema);
+        }
+
+        if (m_version == kDraft7) {
+            if ((itr = object.find("exclusiveMinimum")) != object.end()) {
+                rootSchema.addConstraintToSubschema(
+                        makeMinimumConstraintExclusive(itr->second), &subschema);
+            }
+
+            if ((itr = object.find("minimum")) != object.end()) {
+                rootSchema.addConstraintToSubschema(
+                        makeMinimumConstraint<AdapterType>(itr->second, nullptr),
+                        &subschema);
+            }
+        } else if ((itr = object.find("minimum")) != object.end()) {
+            typename AdapterType::Object::const_iterator exclusiveMinimumItr = object.find("exclusiveMinimum");
+            if (exclusiveMinimumItr == object.end()) {
+                rootSchema.addConstraintToSubschema(
+                        makeMinimumConstraint<AdapterType>(itr->second, nullptr),
+                        &subschema);
+            } else {
+                rootSchema.addConstraintToSubschema(
+                        makeMinimumConstraint<AdapterType>(itr->second, &exclusiveMinimumItr->second),
+                        &subschema);
+            }
+        } else if (object.find("exclusiveMinimum") != object.end()) {
+            throwRuntimeError("'exclusiveMinimum' constraint only valid if a 'minimum' "
+                    "constraint is also present");
+        }
+
+        if ((itr = object.find("minItems")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeMinItemsConstraint(itr->second), &subschema);
+        }
+
+        if ((itr = object.find("minLength")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeMinLengthConstraint(itr->second), &subschema);
+        }
+
+        if ((itr = object.find("minProperties")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeMinPropertiesConstraint(itr->second), &subschema);
+        }
+
+        if ((itr = object.find("multipleOf")) != object.end()) {
+            if (m_version == kDraft3) {
+                throwRuntimeError("'multipleOf' constraint not available in draft 3");
+            } else if (itr->second.maybeInteger()) {
+                rootSchema.addConstraintToSubschema(
+                        makeMultipleOfIntConstraint(itr->second),
+                        &subschema);
+            } else if (itr->second.maybeDouble()) {
+                rootSchema.addConstraintToSubschema(
+                        makeMultipleOfDoubleConstraint(itr->second),
+                        &subschema);
+            } else {
+                throwRuntimeError("Expected an numeric value for 'divisibleBy' constraint.");
+            }
+        }
+
+        if ((itr = object.find("not")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeNotConstraint(rootSchema, rootNode, itr->second, updatedScope, nodePath + "/not", fetchDoc,
+                            docCache, schemaCache),
+                    &subschema);
+        }
+
+        if ((itr = object.find("oneOf")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeOneOfConstraint(rootSchema, rootNode, itr->second, updatedScope, nodePath + "/oneOf", fetchDoc,
+                            docCache, schemaCache),
+                    &subschema);
+        }
+
+        if ((itr = object.find("pattern")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makePatternConstraint(itr->second), &subschema);
+        }
+
+        {
+            // Check for schema keywords that require the creation of a
+            // PropertiesConstraint instance.
+            const typename AdapterType::Object::const_iterator
+                propertiesItr = object.find("properties"),
+                patternPropertiesItr = object.find("patternProperties"),
+                additionalPropertiesItr = object.find("additionalProperties");
+            if (object.end() != propertiesItr ||
+                object.end() != patternPropertiesItr ||
+                object.end() != additionalPropertiesItr) {
+                rootSchema.addConstraintToSubschema(
+                        makePropertiesConstraint(rootSchema, rootNode,
+                                propertiesItr != object.end() ? &propertiesItr->second : nullptr,
+                                patternPropertiesItr != object.end() ? &patternPropertiesItr->second : nullptr,
+                                additionalPropertiesItr != object.end() ? &additionalPropertiesItr->second : nullptr,
+                                updatedScope, nodePath + "/properties",
+                                nodePath + "/patternProperties",
+                                nodePath + "/additionalProperties",
+                                fetchDoc, &subschema, docCache, schemaCache),
+                        &subschema);
+            }
+        }
+
+        if ((itr = object.find("propertyNames")) != object.end()) {
+            if (m_version == kDraft7) {
+                rootSchema.addConstraintToSubschema(
+                      makePropertyNamesConstraint(rootSchema, rootNode, itr->second, updatedScope,
+                              nodePath, fetchDoc, docCache, schemaCache),
+                      &subschema);
+            } else {
+                throwRuntimeError("Not supported");
+            }
+        }
+
+        if ((itr = object.find("required")) != object.end()) {
+            if (m_version == kDraft3) {
+                if (parentSubschema && ownName) {
+                    opt::optional<constraints::RequiredConstraint> constraint =
+                            makeRequiredConstraintForSelf(itr->second, *ownName);
+                    if (constraint) {
+                        rootSchema.addConstraintToSubschema(*constraint, parentSubschema);
+                    }
+                } else {
+                    throwRuntimeError("'required' constraint not valid here");
+                }
+            } else {
+                rootSchema.addConstraintToSubschema(makeRequiredConstraint(itr->second), &subschema);
+            }
+        }
+
+        if ((itr = object.find("title")) != object.end()) {
+            if (itr->second.maybeString()) {
+                rootSchema.setSubschemaTitle(&subschema, itr->second.asString());
+            } else {
+                throwRuntimeError("'title' attribute should have a string value");
+            }
+        }
+
+        if ((itr = object.find("type")) != object.end()) {
+            rootSchema.addConstraintToSubschema(
+                    makeTypeConstraint(rootSchema, rootNode, itr->second, updatedScope, nodePath + "/type", fetchDoc,
+                            docCache, schemaCache),
+                    &subschema);
+        }
+
+        if ((itr = object.find("uniqueItems")) != object.end()) {
+            opt::optional<constraints::UniqueItemsConstraint> constraint = makeUniqueItemsConstraint(itr->second);
+            if (constraint) {
+                rootSchema.addConstraintToSubschema(*constraint, &subschema);
+            }
+        }
+
+        for (const auto & constraintBuilder : constraintBuilders) {
+            if ((itr = object.find(constraintBuilder.first)) != object.end()) {
+                constraints::Constraint *constraint = nullptr;
+#if VALIJSON_USE_EXCEPTIONS
+                try {
+#endif
+                    constraint = constraintBuilder.second->make(itr->second);
+                    rootSchema.addConstraintToSubschema(*constraint, &subschema);
+                    delete constraint;
+#if VALIJSON_USE_EXCEPTIONS
+                } catch (...) {
+                    delete constraint;
+                    throw;
+                }
+#endif
+            }
+        }
+    }
+
+    /**
+     * @brief  Resolves a chain of JSON References before populating a schema
+     *
+     * This helper function is used directly by the publicly visible
+     * populateSchema function. It ensures that the node being parsed is a
+     * concrete node, and not a JSON Reference. This function will call itself
+     * recursively to resolve references until a concrete node is found.
+     *
+     * @param  rootSchema    The Schema instance, and root subschema, through
+     *                       which other subschemas can be created and modified
+     * @param  rootNode      Reference to the node from which JSON References
+     *                       will be resolved when they refer to the current
+     *                       document
+     * @param  node          Reference to node to parse
+     * @param  subschema     Reference to Schema to populate
+     * @param  currentScope  URI for current resolution scope
+     * @param  nodePath      JSON Pointer representing path to current node
+     * @param  fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param  parentSchema  Optional pointer to the parent schema, used to
+     *                       support required keyword in Draft 3
+     * @param  ownName       Optional pointer to a node name, used to support
+     *                       the 'required' keyword in Draft 3
+     * @param  docCache      Cache of resolved and fetched remote documents
+     * @param  schemaCache   Cache of populated schemas
+     */
+    template<typename AdapterType>
+    void resolveThenPopulateSchema(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const Subschema &subschema,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        const Subschema *parentSchema,
+        const std::string *ownName,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        std::string jsonRef;
+        if (!extractJsonReference(node, jsonRef)) {
+            populateSchema(rootSchema, rootNode, node, subschema, currentScope, nodePath, fetchDoc, parentSchema,
+                    ownName, docCache, schemaCache);
+            return;
+        }
+
+        // Returns a document URI if the reference points somewhere
+        // other than the current document
+        const opt::optional<std::string> documentUri = internal::json_reference::getJsonReferenceUri(jsonRef);
+
+        // Extract JSON Pointer from JSON Reference
+        const std::string actualJsonPointer = sanitiseJsonPointer(
+                internal::json_reference::getJsonReferencePointer(jsonRef));
+
+        if (documentUri && internal::uri::isUriAbsolute(*documentUri)) {
+            // Resolve reference against remote document
+            if (!fetchDoc) {
+                throwRuntimeError("Fetching of remote JSON References not enabled.");
+            }
+
+            const typename DocumentCache<AdapterType>::DocumentType *newDoc = fetchDoc(*documentUri);
+
+            // Can't proceed without the remote document
+            if (!newDoc) {
+                throwRuntimeError("Failed to fetch referenced schema document: " + *documentUri);
+            }
+
+            // Add to document cache
+            typedef typename DocumentCache<AdapterType>::Type::value_type DocCacheValueType;
+
+            docCache.insert(DocCacheValueType(*documentUri, newDoc));
+
+            const AdapterType newRootNode(*newDoc);
+
+            const AdapterType &referencedAdapter =
+                internal::json_pointer::resolveJsonPointer(newRootNode, actualJsonPointer);
+
+            // TODO: Need to detect degenerate circular references
+            resolveThenPopulateSchema(rootSchema, newRootNode, referencedAdapter, subschema, {}, actualJsonPointer,
+                    fetchDoc, parentSchema, ownName, docCache, schemaCache);
+
+        } else {
+            const AdapterType &referencedAdapter =
+                    internal::json_pointer::resolveJsonPointer(rootNode, actualJsonPointer);
+
+            // TODO: Need to detect degenerate circular references
+            resolveThenPopulateSchema(rootSchema, rootNode, referencedAdapter, subschema, {}, actualJsonPointer,
+                    fetchDoc, parentSchema, ownName, docCache, schemaCache);
+        }
+    }
+
+    /**
+     * @brief   Make a new AllOfConstraint object
+     *
+     * @param   rootSchema    The Schema instance, and root subschema, through
+     *                        which other subschemas can be created and modified
+     * @param   rootNode      Reference to the node from which JSON References
+     *                        will be resolved when they refer to the current
+     *                        document; used for recursive parsing of schemas
+     * @param   node          JSON node containing an array of child schemas
+     * @param   currentScope  URI for current resolution scope
+     * @param   nodePath      JSON Pointer representing path to current node
+     * @param   fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param   docCache      Cache of resolved and fetched remote documents
+     * @param   schemaCache   Cache of populated schemas
+     *
+     * @return  pointer to a new AllOfConstraint object that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    constraints::AllOfConstraint makeAllOfConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        if (!node.maybeArray()) {
+            throwRuntimeError("Expected array value for 'allOf' constraint.");
+        }
+
+        constraints::AllOfConstraint constraint;
+
+        int index = 0;
+        for (const AdapterType schemaNode : node.asArray()) {
+            if (schemaNode.maybeObject() || (m_version == kDraft7 && schemaNode.isBool())) {
+                const std::string childPath = nodePath + "/" + std::to_string(index);
+                const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                        rootSchema, rootNode, schemaNode, currentScope,
+                        childPath, fetchDoc, nullptr, nullptr, docCache, schemaCache);
+                constraint.addSubschema(subschema);
+                index++;
+            } else {
+                throwRuntimeError("Expected element to be a valid schema in 'allOf' constraint.");
+            }
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new AnyOfConstraint object
+     *
+     * @param   rootSchema    The Schema instance, and root subschema, through
+     *                        which other subschemas can be created and modified
+     * @param   rootNode      Reference to the node from which JSON References
+     *                        will be resolved when they refer to the current
+     *                        document; used for recursive parsing of schemas
+     * @param   node          JSON node containing an array of child schemas
+     * @param   currentScope  URI for current resolution scope
+     * @param   nodePath      JSON Pointer representing path to current node
+     * @param   fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param   docCache      Cache of resolved and fetched remote documents
+     * @param   schemaCache   Cache of populated schemas
+     *
+     * @return  pointer to a new AnyOfConstraint object that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    constraints::AnyOfConstraint makeAnyOfConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        if (!node.maybeArray()) {
+            throwRuntimeError("Expected array value for 'anyOf' constraint.");
+        }
+
+        constraints::AnyOfConstraint constraint;
+
+        int index = 0;
+        for (const AdapterType schemaNode : node.asArray()) {
+            if (schemaNode.maybeObject() || (m_version == kDraft7 && schemaNode.isBool())) {
+                const std::string childPath = nodePath + "/" + std::to_string(index);
+                const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                        rootSchema, rootNode, schemaNode, currentScope,
+                        childPath, fetchDoc, nullptr, nullptr, docCache, schemaCache);
+                constraint.addSubschema(subschema);
+                index++;
+            } else {
+                throwRuntimeError("Expected array element to be a valid schema in 'anyOf' constraint.");
+            }
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new ConditionalConstraint object.
+     *
+     * @param   rootSchema           The Schema instance, and root subschema,
+     *                               through which other subschemas can be
+     *                               created and modified
+     * @param   rootNode             Reference to the node from which JSON
+     *                               References will be resolved when they refer
+     *                               to the current document; used for recursive
+     *                               parsing of schemas
+     * @param   ifNode               Schema that will be used to evaluate the
+     *                               conditional.
+     * @param   thenNode             Optional pointer to a JSON node containing
+     *                               a schema that will be used when the conditional
+     *                               evaluates to true.
+     * @param   elseNode             Optional pointer to a JSON node containing
+     *                               a schema that will be used when the conditional
+     *                               evaluates to false.
+     * @param   currentScope         URI for current resolution scope
+     * @param   containsPath         JSON Pointer representing the path to
+     *                               the 'contains' node
+     * @param   fetchDoc             Function to fetch remote JSON documents
+     *                               (optional)
+     * @param   docCache             Cache of resolved and fetched remote
+     *                               documents
+     * @param   schemaCache          Cache of populated schemas
+     *
+     * @return  pointer to a new ContainsConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::ConditionalConstraint makeConditionalConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &ifNode,
+        const AdapterType *thenNode,
+        const AdapterType *elseNode,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        constraints::ConditionalConstraint constraint;
+
+        const Subschema *ifSubschema = makeOrReuseSchema<AdapterType>(
+                rootSchema, rootNode, ifNode, currentScope,
+                nodePath + "/if", fetchDoc, nullptr, nullptr, docCache,
+                schemaCache);
+        constraint.setIfSubschema(ifSubschema);
+
+        if (thenNode) {
+            const Subschema *thenSubschema = makeOrReuseSchema<AdapterType>(
+                    rootSchema, rootNode, *thenNode, currentScope, nodePath + "/then", fetchDoc, nullptr,
+                    nullptr, docCache, schemaCache);
+            constraint.setThenSubschema(thenSubschema);
+        }
+
+        if (elseNode) {
+            const Subschema *elseSubschema = makeOrReuseSchema<AdapterType>(
+                    rootSchema, rootNode, *elseNode, currentScope, nodePath + "/else", fetchDoc, nullptr,
+                    nullptr, docCache, schemaCache);
+            constraint.setElseSubschema(elseSubschema);
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new ConstConstraint object.
+     *
+     * @param   node  JSON node containing an arbitrary value
+     *
+     * @return  pointer to a new MinimumConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::ConstConstraint makeConstConstraint(const AdapterType &node)
+    {
+        constraints::ConstConstraint constraint;
+        constraint.setValue(node);
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new ContainsConstraint object.
+     *
+     * @param   rootSchema           The Schema instance, and root subschema,
+     *                               through which other subschemas can be
+     *                               created and modified
+     * @param   rootNode             Reference to the node from which JSON
+     *                               References will be resolved when they refer
+     *                               to the current document; used for recursive
+     *                               parsing of schemas
+     * @param   contains             Optional pointer to a JSON node containing
+     *                               an object mapping property names to
+     *                               schemas.
+     * @param   currentScope         URI for current resolution scope
+     * @param   containsPath         JSON Pointer representing the path to
+     *                               the 'contains' node
+     * @param   fetchDoc             Function to fetch remote JSON documents
+     *                               (optional)
+     * @param   docCache             Cache of resolved and fetched remote
+     *                               documents
+     * @param   schemaCache          Cache of populated schemas
+     *
+     * @return  pointer to a new ContainsConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::ContainsConstraint makeContainsConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &contains,
+        const opt::optional<std::string> currentScope,
+        const std::string &containsPath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        constraints::ContainsConstraint constraint;
+
+        if (contains.isObject() || (m_version == kDraft7 && contains.maybeBool())) {
+            const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                    rootSchema, rootNode, contains, currentScope, containsPath,
+                    fetchDoc, nullptr, nullptr, docCache, schemaCache);
+            constraint.setSubschema(subschema);
+
+        } else if (contains.maybeObject()) {
+            // If a loosely-typed Adapter type is being used, then we'll
+            // assume that an empty schema has been provided.
+            constraint.setSubschema(rootSchema.emptySubschema());
+
+        } else {
+            // All other formats will result in an exception being thrown.
+            throwRuntimeError("Expected valid schema for 'contains' constraint.");
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new DependenciesConstraint object
+     *
+     * The dependencies for a property can be defined several ways. When parsing
+     * a Draft 4 schema, the following can be used:
+     *  - an array that lists the name of each property that must be present
+     *    if the dependent property is present
+     *  - an object that specifies a schema which must be satisfied if the
+     *    dependent property is present
+     *
+     * When parsing a Draft 3 schema, in addition to the formats above, the
+     * following format can be used:
+     *  - a string that names a single property that must be present if the
+     *    dependent property is presnet
+     *
+     * Multiple methods can be used in the same dependency constraint.
+     *
+     * If the format of any part of the the dependency node does not match one
+     * of these formats, an exception will be thrown.
+     *
+     * @param   rootSchema    The Schema instance, and root subschema, through
+     *                        which other subschemas can be created and modified
+     * @param   rootNode      Reference to the node from which JSON References
+     *                        will be resolved when they refer to the current
+     *                        document; used for recursive parsing of schemas
+     * @param   node          JSON node containing an object that defines a
+     *                        mapping of properties to their dependencies.
+     * @param   currentScope  URI for current resolution scope
+     * @param   nodePath      JSON Pointer representing path to current node
+     * @param   fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param   docCache      Cache of resolved and fetched remote documents
+     * @param   schemaCache   Cache of populated schemas
+     *
+     * @return  pointer to a new DependencyConstraint that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    constraints::DependenciesConstraint makeDependenciesConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        if (!node.maybeObject()) {
+            throwRuntimeError("Expected valid subschema for 'dependencies' constraint.");
+        }
+
+        constraints::DependenciesConstraint dependenciesConstraint;
+
+        // Process each of the dependency mappings defined by the object
+        for (const typename AdapterType::ObjectMember member : node.asObject()) {
+
+            // First, we attempt to parse the value of the dependency mapping
+            // as an array of strings. If the Adapter type does not support
+            // strict types, then an empty string or empty object will be cast
+            // to an array, and the resulting dependency list will be empty.
+            // This is equivalent to using an empty object, but does mean that
+            // if the user provides an actual string then this error will not
+            // be detected.
+            if (member.second.maybeArray()) {
+                // Parse an array of dependency names
+                std::vector<std::string> dependentPropertyNames;
+                for (const AdapterType dependencyName : member.second.asArray()) {
+                    if (dependencyName.maybeString()) {
+                        dependentPropertyNames.push_back(dependencyName.getString());
+                    } else {
+                        throwRuntimeError("Expected string value in dependency list of property '" +
+                            member.first + "' in 'dependencies' constraint.");
+                    }
+                }
+
+                dependenciesConstraint.addPropertyDependencies(member.first,
+                        dependentPropertyNames);
+
+            // If the value of dependency mapping could not be processed as an
+            // array, we'll try to process it as an object instead. Note that
+            // strict type comparison is used here, since we've already
+            // exercised the flexibility by loosely-typed Adapter types. If the
+            // value of the dependency mapping is an object, then we'll try to
+            // process it as a dependent schema.
+            } else if (member.second.isObject() || (m_version == kDraft7 && member.second.maybeBool())) {
+                // Parse dependent subschema
+                const Subschema *childSubschema =
+                        makeOrReuseSchema<AdapterType>(rootSchema, rootNode,
+                                member.second, currentScope, nodePath, fetchDoc,
+                                nullptr, nullptr, docCache, schemaCache);
+                dependenciesConstraint.addSchemaDependency(member.first,
+                        childSubschema);
+
+            // If we're supposed to be parsing a Draft3 schema, then the value
+            // of the dependency mapping can also be a string containing the
+            // name of a single dependency.
+            } else if (m_version == kDraft3 && member.second.isString()) {
+                dependenciesConstraint.addPropertyDependency(member.first,
+                        member.second.getString());
+
+            // All other types result in an exception being thrown.
+            } else {
+                throwRuntimeError("Invalid dependencies definition.");
+            }
+        }
+
+        return dependenciesConstraint;
+    }
+
+    /**
+     * @brief   Make a new EnumConstraint object.
+     *
+     * @param   node  JSON node containing an array of values permitted by the
+     *                constraint.
+     *
+     * @return  pointer to a new EnumConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::EnumConstraint makeEnumConstraint(
+        const AdapterType &node)
+    {
+        // Make a copy of each value in the enum array
+        constraints::EnumConstraint constraint;
+        for (const AdapterType value : node.getArray()) {
+            constraint.addValue(value);
+        }
+
+        /// @todo This will make another copy of the values while constructing
+        /// the EnumConstraint. Move semantics in C++11 should make it possible
+        /// to avoid these copies without complicating the implementation of the
+        /// EnumConstraint class.
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new ItemsConstraint object.
+     *
+     * @param   rootSchema           The Schema instance, and root subschema,
+     *                               through which other subschemas can be
+     *                               created and modified
+     * @param   rootNode             Reference to the node from which JSON
+     *                               References will be resolved when they refer
+     *                               to the current document; used for recursive
+     *                               parsing of schemas
+     * @param   items                Optional pointer to a JSON node containing
+     *                               an object mapping property names to
+     *                               schemas.
+     * @param   additionalItems      Optional pointer to a JSON node containing
+     *                               an additional properties schema or a
+     *                               boolean value.
+     * @param   currentScope         URI for current resolution scope
+     * @param   itemsPath            JSON Pointer representing the path to
+     *                               the 'items' node
+     * @param   additionalItemsPath  JSON Pointer representing the path to
+     *                               the 'additionalItems' node
+     * @param   fetchDoc             Function to fetch remote JSON documents
+     *                               (optional)
+     * @param   docCache             Cache of resolved and fetched remote
+     *                               documents
+     * @param   schemaCache          Cache of populated schemas
+     *
+     * @return  pointer to a new ItemsConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::LinearItemsConstraint makeLinearItemsConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType *items,
+        const AdapterType *additionalItems,
+        const opt::optional<std::string> currentScope,
+        const std::string &itemsPath,
+        const std::string &additionalItemsPath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        constraints::LinearItemsConstraint constraint;
+
+        // Construct a Schema object for the the additionalItems constraint,
+        // if the additionalItems property is present
+        if (additionalItems) {
+            if (additionalItems->maybeBool()) {
+                // If the value of the additionalItems property is a boolean
+                // and is set to true, then additional array items do not need
+                // to satisfy any constraints.
+                if (additionalItems->asBool()) {
+                    constraint.setAdditionalItemsSubschema(rootSchema.emptySubschema());
+                }
+            } else if (additionalItems->maybeObject()) {
+                // If the value of the additionalItems property is an object,
+                // then it should be parsed into a Schema object, which will be
+                // used to validate additional array items.
+                const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                        rootSchema, rootNode, *additionalItems, currentScope,
+                        additionalItemsPath, fetchDoc, nullptr, nullptr, docCache,
+                        schemaCache);
+                constraint.setAdditionalItemsSubschema(subschema);
+            } else {
+                // Any other format for the additionalItems property will result
+                // in an exception being thrown.
+                throwRuntimeError("Expected bool or object value for 'additionalItems'");
+            }
+        } else {
+            // The default value for the additionalItems property is an empty
+            // object, which means that additional array items do not need to
+            // satisfy any constraints.
+            constraint.setAdditionalItemsSubschema(rootSchema.emptySubschema());
+        }
+
+        // Construct a Schema object for each item in the items array.
+        // If the items constraint is not provided, then array items
+        // will be validated against the additionalItems schema.
+        if (items) {
+            if (items->isArray()) {
+                // If the items constraint contains an array, then it should
+                // contain a list of child schemas which will be used to
+                // validate the values at the corresponding indexes in a target
+                // array.
+                int index = 0;
+                for (const AdapterType v : items->getArray()) {
+                    const std::string childPath = itemsPath + "/" +
+                            std::to_string(index);
+                    const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                            rootSchema, rootNode, v, currentScope, childPath,
+                            fetchDoc, nullptr, nullptr, docCache, schemaCache);
+                    constraint.addItemSubschema(subschema);
+                    index++;
+                }
+            } else {
+                throwRuntimeError("Expected array value for non-singular 'items' constraint.");
+            }
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new ItemsConstraint object.
+     *
+     * @param   rootSchema           The Schema instance, and root subschema,
+     *                               through which other subschemas can be
+     *                               created and modified
+     * @param   rootNode             Reference to the node from which JSON
+     *                               References will be resolved when they refer
+     *                               to the current document; used for recursive
+     *                               parsing of schemas
+     * @param   items                Optional pointer to a JSON node containing
+     *                               an object mapping property names to
+     *                               schemas.
+     * @param   additionalItems      Optional pointer to a JSON node containing
+     *                               an additional properties schema or a
+     *                               boolean value.
+     * @param   currentScope         URI for current resolution scope
+     * @param   itemsPath            JSON Pointer representing the path to
+     *                               the 'items' node
+     * @param   additionalItemsPath  JSON Pointer representing the path to
+     *                               the 'additionalItems' node
+     * @param   fetchDoc             Function to fetch remote JSON documents
+     *                               (optional)
+     * @param   docCache             Cache of resolved and fetched remote
+     *                               documents
+     * @param   schemaCache          Cache of populated schemas
+     *
+     * @return  pointer to a new ItemsConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::SingularItemsConstraint makeSingularItemsConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &items,
+        const opt::optional<std::string> currentScope,
+        const std::string &itemsPath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        constraints::SingularItemsConstraint constraint;
+
+        // Construct a Schema object for each item in the items array, if an
+        // array is provided, or a single Schema object, in an object value is
+        // provided. If the items constraint is not provided, then array items
+        // will be validated against the additionalItems schema.
+        if (items.isObject() || (m_version == kDraft7 && items.maybeBool())) {
+            // If the items constraint contains an object value, then it
+            // should contain a Schema that will be used to validate all
+            // items in a target array. Any schema defined by the
+            // additionalItems constraint will be ignored.
+            const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                    rootSchema, rootNode, items, currentScope, itemsPath,
+                    fetchDoc, nullptr, nullptr, docCache, schemaCache);
+            constraint.setItemsSubschema(subschema);
+
+        } else if (items.maybeObject()) {
+            // If a loosely-typed Adapter type is being used, then we'll
+            // assume that an empty schema has been provided.
+            constraint.setItemsSubschema(rootSchema.emptySubschema());
+
+        } else {
+            // All other formats will result in an exception being thrown.
+            throwRuntimeError("Expected valid schema for singular 'items' constraint.");
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new MaximumConstraint object (draft 3 and 4).
+     *
+     * @param   rootSchema        The Schema instance, and root subschema,
+     *                            through which other subschemas can be
+     *                            created and modified
+     * @param   rootNode          Reference to the node from which JSON
+     *                            References will be resolved when they refer
+     *                            to the current document; used for recursive
+     *                            parsing of schemas
+     * @param   node              JSON node containing the maximum value.
+     * @param   exclusiveMaximum  Optional pointer to a JSON boolean value that
+     *                            indicates whether maximum value is excluded
+     *                            from the range of permitted values.
+     *
+     * @return  pointer to a new MaximumConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::MaximumConstraint makeMaximumConstraint(
+        const AdapterType &node,
+        const AdapterType *exclusiveMaximum)
+    {
+        if (!node.maybeDouble()) {
+            throwRuntimeError("Expected numeric value for maximum constraint.");
+        }
+
+        constraints::MaximumConstraint constraint;
+        constraint.setMaximum(node.asDouble());
+
+        if (exclusiveMaximum) {
+            if (!exclusiveMaximum->maybeBool()) {
+                throwRuntimeError("Expected boolean value for exclusiveMaximum constraint.");
+            }
+
+            constraint.setExclusiveMaximum(exclusiveMaximum->asBool());
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new MaximumConstraint object that is always exclusive (draft 7).
+     *
+     * @param   node       JSON node containing an integer, representing the maximum value.
+     *
+     * @param   exclusive  Optional pointer to a JSON boolean value that indicates whether the
+     *                     maximum value is excluded from the range of permitted values.
+     *
+     * @return  pointer to a new Maximum that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::MaximumConstraint makeMaximumConstraintExclusive(const AdapterType &node)
+    {
+        if (!node.maybeDouble()) {
+            throwRuntimeError("Expected numeric value for exclusiveMaximum constraint.");
+        }
+
+        constraints::MaximumConstraint constraint;
+        constraint.setMaximum(node.asDouble());
+        constraint.setExclusiveMaximum(true);
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new MaxItemsConstraint object.
+     *
+     * @param   node  JSON node containing an integer value representing the
+     *                maximum number of items that may be contaned by an array.
+     *
+     * @return  pointer to a new MaxItemsConstraint that belongs to the caller.
+     */
+    template<typename AdapterType>
+    constraints::MaxItemsConstraint makeMaxItemsConstraint(
+        const AdapterType &node)
+    {
+        if (node.maybeInteger()) {
+            const int64_t value = node.asInteger();
+            if (value >= 0) {
+                constraints::MaxItemsConstraint constraint;
+                constraint.setMaxItems(value);
+                return constraint;
+            }
+        }
+
+        throwRuntimeError("Expected non-negative integer value for 'maxItems' constraint.");
+    }
+
+    /**
+     * @brief   Make a new MaxLengthConstraint object.
+     *
+     * @param   node  JSON node containing an integer value representing the
+     *                maximum length of a string.
+     *
+     * @return  pointer to a new MaxLengthConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::MaxLengthConstraint makeMaxLengthConstraint(
+        const AdapterType &node)
+    {
+        if (node.maybeInteger()) {
+            const int64_t value = node.asInteger();
+            if (value >= 0) {
+                constraints::MaxLengthConstraint constraint;
+                constraint.setMaxLength(value);
+                return constraint;
+            }
+        }
+
+        throwRuntimeError("Expected a non-negative integer value for 'maxLength' constraint.");
+    }
+
+    /**
+     * @brief   Make a new MaxPropertiesConstraint object.
+     *
+     * @param   node  JSON node containing an integer value representing the
+     *                maximum number of properties that may be contained by an
+     *                object.
+     *
+     * @return  pointer to a new MaxPropertiesConstraint that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    constraints::MaxPropertiesConstraint makeMaxPropertiesConstraint(
+        const AdapterType &node)
+    {
+        if (node.maybeInteger()) {
+            int64_t value = node.asInteger();
+            if (value >= 0) {
+                constraints::MaxPropertiesConstraint constraint;
+                constraint.setMaxProperties(value);
+                return constraint;
+            }
+        }
+
+        throwRuntimeError("Expected a non-negative integer for 'maxProperties' constraint.");
+    }
+
+    /**
+     * @brief  Make a new MinimumConstraint object (draft 3 and 4).
+     *
+     * @param  node              JSON node containing an integer, representing
+     *                           the minimum value.
+     *
+     * @param  exclusiveMaximum  Optional pointer to a JSON boolean value that
+     *                           indicates whether the minimum value is
+     *                           excluded from the range of permitted values.
+     *
+     * @return  pointer to a new MinimumConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::MinimumConstraint makeMinimumConstraint(
+        const AdapterType &node,
+        const AdapterType *exclusiveMinimum)
+    {
+        if (!node.maybeDouble()) {
+            throwRuntimeError("Expected numeric value for minimum constraint.");
+        }
+
+        constraints::MinimumConstraint constraint;
+        constraint.setMinimum(node.asDouble());
+
+        if (exclusiveMinimum) {
+            if (!exclusiveMinimum->maybeBool()) {
+                throwRuntimeError("Expected boolean value for 'exclusiveMinimum' constraint.");
+            }
+
+            constraint.setExclusiveMinimum(exclusiveMinimum->asBool());
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new MinimumConstraint object that is always exclusive (draft 7).
+     *
+     * @param   node       JSON node containing an integer, representing the minimum value.
+     *
+     * @param   exclusive  Optional pointer to a JSON boolean value that indicates whether the
+     *                     minimum value is excluded from the range of permitted values.
+     *
+     * @return  pointer to a new MinimumConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::MinimumConstraint makeMinimumConstraintExclusive(const AdapterType &node)
+    {
+        if (!node.maybeDouble()) {
+            throwRuntimeError("Expected numeric value for exclusiveMinimum constraint.");
+        }
+
+        constraints::MinimumConstraint constraint;
+        constraint.setMinimum(node.asDouble());
+        constraint.setExclusiveMinimum(true);
+        return constraint;
+    }
+
+    /**
+     * @brief  Make a new MinItemsConstraint object.
+     *
+     * @param  node  JSON node containing an integer value representing the
+     *               minimum number of items that may be contained by an array.
+     *
+     * @return  pointer to a new MinItemsConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::MinItemsConstraint makeMinItemsConstraint(const AdapterType &node)
+    {
+        if (node.maybeInteger()) {
+            const int64_t value = node.asInteger();
+            if (value >= 0) {
+                constraints::MinItemsConstraint constraint;
+                constraint.setMinItems(value);
+                return constraint;
+            }
+        }
+
+        throwRuntimeError("Expected a non-negative integer value for 'minItems' constraint.");
+    }
+
+    /**
+     * @brief  Make a new MinLengthConstraint object.
+     *
+     * @param  node  JSON node containing an integer value representing the
+     *               minimum length of a string.
+     *
+     * @return  pointer to a new MinLengthConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::MinLengthConstraint makeMinLengthConstraint(const AdapterType &node)
+    {
+        if (node.maybeInteger()) {
+            const int64_t value = node.asInteger();
+            if (value >= 0) {
+                constraints::MinLengthConstraint constraint;
+                constraint.setMinLength(value);
+                return constraint;
+            }
+        }
+
+        throwRuntimeError("Expected a non-negative integer value for 'minLength' constraint.");
+    }
+
+
+    /**
+     * @brief   Make a new MaxPropertiesConstraint object.
+     *
+     * @param   node  JSON node containing an integer value representing the
+     *                minimum number of properties that may be contained by an
+     *                object.
+     *
+     * @return  pointer to a new MinPropertiesConstraint that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    constraints::MinPropertiesConstraint makeMinPropertiesConstraint(const AdapterType &node)
+    {
+        if (node.maybeInteger()) {
+            int64_t value = node.asInteger();
+            if (value >= 0) {
+                constraints::MinPropertiesConstraint constraint;
+                constraint.setMinProperties(value);
+                return constraint;
+            }
+        }
+
+        throwRuntimeError("Expected a non-negative integer for 'minProperties' constraint.");
+    }
+
+    /**
+     * @brief   Make a new MultipleOfDoubleConstraint object
+     *
+     * @param   node  JSON node containing an numeric value that a target value
+     *                must divide by in order to satisfy this constraint
+     *
+     * @return  a MultipleOfConstraint
+     */
+    template<typename AdapterType>
+    constraints::MultipleOfDoubleConstraint makeMultipleOfDoubleConstraint(const AdapterType &node)
+    {
+        constraints::MultipleOfDoubleConstraint constraint;
+        constraint.setDivisor(node.asDouble());
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new MultipleOfIntConstraint object
+     *
+     * @param   node  JSON node containing a numeric value that a target value
+     *                must divide by in order to satisfy this constraint
+     *
+     * @return  a MultipleOfIntConstraint
+     */
+    template<typename AdapterType>
+    constraints::MultipleOfIntConstraint makeMultipleOfIntConstraint(const AdapterType &node)
+    {
+        constraints::MultipleOfIntConstraint constraint;
+        constraint.setDivisor(node.asInteger());
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new NotConstraint object
+     *
+     * @param   rootSchema    The Schema instance, and root subschema, through
+     *                        which other subschemas can be created and modified
+     * @param   rootNode      Reference to the node from which JSON References
+     *                        will be resolved when they refer to the current
+     *                        document; used for recursive parsing of schemas
+     * @param   node          JSON node containing a schema
+     * @param   currentScope  URI for current resolution scope
+     * @param   nodePath      JSON Pointer representing path to current node
+     * @param   fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param   docCache      Cache of resolved and fetched remote documents
+     * @param   schemaCache   Cache of populated schemas
+     *
+     * @return  pointer to a new NotConstraint object that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::NotConstraint makeNotConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        if (node.maybeObject() || (m_version == kDraft7 && node.maybeBool())) {
+            const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                    rootSchema, rootNode, node, currentScope, nodePath,
+                    fetchDoc, nullptr, nullptr, docCache, schemaCache);
+            constraints::NotConstraint constraint;
+            constraint.setSubschema(subschema);
+            return constraint;
+        }
+
+        throwRuntimeError("Expected object value for 'not' constraint.");
+    }
+
+    /**
+     * @brief   Make a new OneOfConstraint object
+     *
+     * @param   rootSchema    The Schema instance, and root subschema, through
+     *                        which other subschemas can be created and modified
+     * @param   rootNode      Reference to the node from which JSON References
+     *                        will be resolved when they refer to the current
+     *                        document; used for recursive parsing of schemas
+     * @param   node          JSON node containing an array of child schemas
+     * @param   currentScope  URI for current resolution scope
+     * @param   nodePath      JSON Pointer representing path to current node
+     * @param   fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param   docCache      Cache of resolved and fetched remote documents
+     * @param   schemaCache   Cache of populated schemas
+     *
+     * @return  pointer to a new OneOfConstraint that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::OneOfConstraint makeOneOfConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        constraints::OneOfConstraint constraint;
+
+        int index = 0;
+        for (const AdapterType schemaNode : node.getArray()) {
+            const std::string childPath = nodePath + "/" + std::to_string(index);
+            const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                rootSchema, rootNode, schemaNode, currentScope, childPath,
+                fetchDoc, nullptr, nullptr, docCache, schemaCache);
+            constraint.addSubschema(subschema);
+            index++;
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new PatternConstraint object.
+     *
+     * @param   node      JSON node containing a pattern string
+     *
+     * @return  pointer to a new PatternConstraint object that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    constraints::PatternConstraint makePatternConstraint(
+        const AdapterType &node)
+    {
+        constraints::PatternConstraint constraint;
+        constraint.setPattern(node.getString());
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new Properties object.
+     *
+     * @param   rootSchema                The Schema instance, and root
+     *                                    subschema, through which other
+     *                                    subschemas can be created and modified
+     * @param   rootNode                  Reference to the node from which JSON
+     *                                    References will be resolved when they
+     *                                    refer to the current document; used
+     *                                    for recursive parsing of schemas
+     * @param   properties                Optional pointer to a JSON node
+     *                                    containing an object mapping property
+     *                                    names to schemas.
+     * @param   patternProperties         Optional pointer to a JSON node
+     *                                    containing an object mapping pattern
+     *                                    property names to schemas.
+     * @param   additionalProperties      Optional pointer to a JSON node
+     *                                    containing an additional properties
+     *                                    schema or a boolean value.
+     * @param   currentScope              URI for current resolution scope
+     * @param   propertiesPath            JSON Pointer representing the path to
+     *                                    the 'properties' node
+     * @param   patternPropertiesPath     JSON Pointer representing the path to
+     *                                    the 'patternProperties' node
+     * @param   additionalPropertiesPath  JSON Pointer representing the path to
+     *                                    the 'additionalProperties' node
+     * @param   fetchDoc                  Function to fetch remote JSON
+     *                                    documents (optional)
+     * @param   parentSubschema           Optional pointer to the Schema of the
+     *                                    parent object, needed to support the
+     *                                    'required' keyword in Draft 3
+     * @param   docCache                  Cache of resolved and fetched remote
+     *                                    documents
+     * @param   schemaCache               Cache of populated schemas
+     *
+     * @return  pointer to a new Properties that belongs to the caller
+     */
+    template<typename AdapterType>
+    constraints::PropertiesConstraint makePropertiesConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType *properties,
+        const AdapterType *patternProperties,
+        const AdapterType *additionalProperties,
+        const opt::optional<std::string> currentScope,
+        const std::string &propertiesPath,
+        const std::string &patternPropertiesPath,
+        const std::string &additionalPropertiesPath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        const Subschema *parentSubschema,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        typedef typename AdapterType::ObjectMember Member;
+
+        constraints::PropertiesConstraint constraint;
+
+        // Create subschemas for 'properties' constraint
+        if (properties) {
+            for (const Member m : properties->getObject()) {
+                const std::string &property = m.first;
+                const std::string childPath = propertiesPath + "/" + property;
+                const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                        rootSchema, rootNode, m.second, currentScope, childPath,
+                        fetchDoc, parentSubschema, &property, docCache,
+                        schemaCache);
+                constraint.addPropertySubschema(property, subschema);
+            }
+        }
+
+        // Create subschemas for 'patternProperties' constraint
+        if (patternProperties) {
+            for (const Member m : patternProperties->getObject()) {
+                const std::string &pattern = m.first;
+                const std::string childPath = patternPropertiesPath + "/" + pattern;
+                const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                        rootSchema, rootNode, m.second, currentScope, childPath,
+                        fetchDoc, parentSubschema, &pattern, docCache,
+                        schemaCache);
+                constraint.addPatternPropertySubschema(pattern, subschema);
+            }
+        }
+
+        // Create an additionalItems subschema if required
+        if (additionalProperties) {
+            // If additionalProperties has been set, check for a boolean value.
+            // Setting 'additionalProperties' to true allows the values of
+            // additional properties to take any form. Setting it false
+            // prohibits the use of additional properties.
+            // If additionalProperties is instead an object, it should be
+            // parsed as a schema. If additionalProperties has any other type,
+            // then the schema is not valid.
+            if (additionalProperties->isBool() ||
+                additionalProperties->maybeBool()) {
+                // If it has a boolean value that is 'true', then an empty
+                // schema should be used.
+                if (additionalProperties->asBool()) {
+                    constraint.setAdditionalPropertiesSubschema(rootSchema.emptySubschema());
+                }
+            } else if (additionalProperties->isObject()) {
+                // If additionalProperties is an object, it should be used as
+                // a child schema.
+                const Subschema *subschema = makeOrReuseSchema<AdapterType>(
+                        rootSchema, rootNode, *additionalProperties,
+                        currentScope, additionalPropertiesPath, fetchDoc, nullptr,
+                        nullptr, docCache, schemaCache);
+                constraint.setAdditionalPropertiesSubschema(subschema);
+            } else {
+                // All other types are invalid
+                throwRuntimeError("Invalid type for 'additionalProperties' constraint.");
+            }
+        } else {
+            // If an additionalProperties constraint is not provided, then the
+            // default value is an empty schema.
+            constraint.setAdditionalPropertiesSubschema(rootSchema.emptySubschema());
+        }
+
+        return constraint;
+    }
+
+    template<typename AdapterType>
+    constraints::PropertyNamesConstraint makePropertyNamesConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &currentNode,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        const Subschema *subschema = makeOrReuseSchema<AdapterType>(rootSchema, rootNode, currentNode, currentScope,
+                nodePath, fetchDoc, nullptr, nullptr, docCache, schemaCache);
+        constraints::PropertyNamesConstraint constraint;
+        constraint.setSubschema(subschema);
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new RequiredConstraint.
+     *
+     * This function is used to create new RequiredContraint objects for
+     * Draft 3 schemas.
+     *
+     * @param   node  Node containing a boolean value.
+     * @param   name  Name of the required attribute.
+     *
+     * @return  pointer to a new RequiredConstraint object that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    opt::optional<constraints::RequiredConstraint>
+            makeRequiredConstraintForSelf(const AdapterType &node,
+                    const std::string &name)
+    {
+        if (!node.maybeBool()) {
+            throwRuntimeError("Expected boolean value for 'required' attribute.");
+        }
+
+        if (node.asBool()) {
+            constraints::RequiredConstraint constraint;
+            constraint.addRequiredProperty(name);
+            return constraint;
+        }
+
+        return opt::optional<constraints::RequiredConstraint>();
+    }
+
+    /**
+     * @brief   Make a new RequiredConstraint.
+     *
+     * This function is used to create new RequiredContraint objects for
+     * Draft 4 schemas.
+     *
+     * @param   node  Node containing an array of strings.
+     *
+     * @return  pointer to a new RequiredConstraint object that belongs to the
+     *          caller
+     */
+    template<typename AdapterType>
+    constraints::RequiredConstraint makeRequiredConstraint(
+        const AdapterType &node)
+    {
+        constraints::RequiredConstraint constraint;
+
+        for (const AdapterType v : node.getArray()) {
+            if (!v.maybeString()) {
+                throwRuntimeError("Expected required property name to be a string value");
+            }
+
+            constraint.addRequiredProperty(v.getString());
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new TypeConstraint object
+     *
+     * @param   rootSchema    The Schema instance, and root subschema, through
+     *                        which other subschemas can be created and modified
+     * @param   rootNode      Reference to the node from which JSON References
+     *                        will be resolved when they refer to the current
+     *                        document; used for recursive parsing of schemas
+     * @param   node          Node containing the name of a JSON type
+     * @param   currentScope  URI for current resolution scope
+     * @param   nodePath      JSON Pointer representing path to current node
+     * @param   fetchDoc      Function to fetch remote JSON documents (optional)
+     * @param   docCache      Cache of resolved and fetched remote documents
+     * @param   schemaCache   Cache of populated schemas
+     *
+     * @return  pointer to a new TypeConstraint object.
+     */
+    template<typename AdapterType>
+    constraints::TypeConstraint makeTypeConstraint(
+        Schema &rootSchema,
+        const AdapterType &rootNode,
+        const AdapterType &node,
+        const opt::optional<std::string> currentScope,
+        const std::string &nodePath,
+        const typename FunctionPtrs<AdapterType>::FetchDoc fetchDoc,
+        typename DocumentCache<AdapterType>::Type &docCache,
+        SchemaCache &schemaCache)
+    {
+        typedef constraints::TypeConstraint TypeConstraint;
+
+        TypeConstraint constraint;
+
+        if (node.maybeString()) {
+            const TypeConstraint::JsonType type = TypeConstraint::jsonTypeFromString(node.getString());
+            if (type == TypeConstraint::kAny && m_version == kDraft4) {
+                throwRuntimeError("'any' type is not supported in version 4 schemas.");
+            }
+
+            constraint.addNamedType(type);
+
+        } else if (node.maybeArray()) {
+            int index = 0;
+            for (const AdapterType v : node.getArray()) {
+                if (v.maybeString()) {
+                    const TypeConstraint::JsonType type = TypeConstraint::jsonTypeFromString(v.getString());
+                    if (type == TypeConstraint::kAny && m_version == kDraft4) {
+                        throwRuntimeError("'any' type is not supported in version 4 schemas.");
+                    }
+
+                    constraint.addNamedType(type);
+
+                } else if (v.maybeObject() && m_version == kDraft3) {
+                    const std::string childPath = nodePath + "/" + std::to_string(index);
+                    const Subschema *subschema = makeOrReuseSchema<AdapterType>(rootSchema, rootNode, v, currentScope,
+                            childPath, fetchDoc, nullptr, nullptr, docCache, schemaCache);
+                    constraint.addSchemaType(subschema);
+
+                } else {
+                    throwRuntimeError("Type name should be a string.");
+                }
+
+                index++;
+            }
+
+        } else if (node.maybeObject() && m_version == kDraft3) {
+            const Subschema *subschema = makeOrReuseSchema<AdapterType>(rootSchema, rootNode, node, currentScope,
+                    nodePath, fetchDoc, nullptr, nullptr, docCache, schemaCache);
+            constraint.addSchemaType(subschema);
+
+        } else {
+            throwRuntimeError("Type name should be a string.");
+        }
+
+        return constraint;
+    }
+
+    /**
+     * @brief   Make a new UniqueItemsConstraint object.
+     *
+     * @param   node  Node containing a boolean value.
+     *
+     * @return  pointer to a new UniqueItemsConstraint object that belongs to
+     *          the caller, or nullptr if the boolean value is false.
+     */
+    template<typename AdapterType>
+    opt::optional<constraints::UniqueItemsConstraint> makeUniqueItemsConstraint(const AdapterType &node)
+    {
+        if (node.isBool() || node.maybeBool()) {
+            // If the boolean value is true, this function will return a pointer
+            // to a new UniqueItemsConstraint object. If it is value, then the
+            // constraint is redundant, so nullptr is returned instead.
+            if (node.asBool()) {
+                return constraints::UniqueItemsConstraint();
+            } else {
+                return opt::optional<constraints::UniqueItemsConstraint>();
+            }
+        }
+
+        throwRuntimeError("Expected boolean value for 'uniqueItems' constraint.");
+    }
+
+private:
+
+    /// Version of JSON Schema that should be expected when parsing
+    const Version m_version;
+};
+
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/subschema.hpp b/subprojects/valijson/include/valijson/subschema.hpp
new file mode 100644
index 000000000..abee6c42b
--- /dev/null
+++ b/subprojects/valijson/include/valijson/subschema.hpp
@@ -0,0 +1,311 @@
+#pragma once
+
+#include <vector>
+
+#include <memory>
+
+#include <valijson/constraints/constraint.hpp>
+#include <valijson/internal/optional.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+
+/**
+ * Represents a sub-schema within a JSON Schema
+ *
+ * While all JSON Schemas have at least one sub-schema, the root, some will
+ * have additional sub-schemas that are defined as part of constraints that are
+ * included in the schema. For example, a 'oneOf' constraint maintains a set of
+ * references to one or more nested sub-schemas. As per the definition of a
+ * oneOf constraint, a document is valid within that constraint if it validates
+ * against one of the nested sub-schemas.
+ */
+class Subschema
+{
+public:
+
+    /// Typedef for custom new-/malloc-like function
+    typedef void * (*CustomAlloc)(size_t size);
+
+    /// Typedef for custom free-like function
+    typedef void (*CustomFree)(void *);
+
+    /// Typedef the Constraint class into the local namespace for convenience
+    typedef constraints::Constraint Constraint;
+
+    /// Typedef for a function that can be applied to each of the Constraint
+    /// instances owned by a Schema.
+    typedef std::function<bool (const Constraint &)> ApplyFunction;
+
+    // Disable copy construction
+    Subschema(const Subschema &) = delete;
+
+    // Disable copy assignment
+    Subschema & operator=(const Subschema &) = delete;
+
+    /**
+     * @brief  Construct a new Subschema object
+     */
+    Subschema()
+      : m_allocFn(::operator new)
+      , m_freeFn(::operator delete)
+      , m_alwaysInvalid(false) { }
+
+    /**
+     * @brief  Construct a new Subschema using custom memory management
+     *         functions
+     *
+     * @param  allocFn  malloc- or new-like function to allocate memory
+     *                  within Schema, such as for Subschema instances
+     * @param  freeFn   free-like function to free memory allocated with
+     *                  the `customAlloc` function
+     */
+    Subschema(CustomAlloc allocFn, CustomFree freeFn)
+      : m_allocFn(allocFn)
+      , m_freeFn(freeFn)
+      , m_alwaysInvalid(false)
+    {
+        // explicitly initialise optionals. See: https://github.com/tristanpenman/valijson/issues/124
+        m_description = opt::nullopt;
+        m_id = opt::nullopt;
+        m_title = opt::nullopt;
+    }
+
+    /**
+     * @brief  Clean up and free all memory managed by the Subschema
+     */
+    virtual ~Subschema()
+    {
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            for (auto constConstraint : m_constraints) {
+                auto *constraint = const_cast<Constraint *>(constConstraint);
+                constraint->~Constraint();
+                m_freeFn(constraint);
+            }
+            m_constraints.clear();
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (const std::exception &e) {
+            fprintf(stderr, "Caught an exception in Subschema destructor: %s",
+                    e.what());
+        }
+#endif
+    }
+
+    /**
+     * @brief  Add a constraint to this sub-schema
+     *
+     * The constraint will be copied before being added to the list of
+     * constraints for this Subschema. Note that constraints will be copied
+     * only as deep as references to other Subschemas - e.g. copies of
+     * constraints that refer to sub-schemas, will continue to refer to the
+     * same Subschema instances.
+     *
+     * @param  constraint  Reference to the constraint to copy
+     */
+    void addConstraint(const Constraint &constraint)
+    {
+        Constraint *newConstraint = constraint.clone(m_allocFn, m_freeFn);
+#if VALIJSON_USE_EXCEPTIONS
+        try {
+#endif
+            m_constraints.push_back(newConstraint);
+#if VALIJSON_USE_EXCEPTIONS
+        } catch (...) {
+            newConstraint->~Constraint();
+            m_freeFn(newConstraint);
+            throw;
+        }
+#endif
+    }
+
+    /**
+     * @brief  Invoke a function on each child Constraint
+     *
+     * This function will apply the callback function to each constraint in
+     * the Subschema, even if one of the invokations returns \c false. However,
+     * if one or more invokations of the callback function return \c false,
+     * this function will also return \c false.
+     *
+     * @returns  \c true if all invokations of the callback function are
+     *           successful, \c false otherwise
+     */
+    bool apply(ApplyFunction &applyFunction) const
+    {
+        bool allTrue = true;
+        for (const Constraint *constraint : m_constraints) {
+            allTrue = allTrue && applyFunction(*constraint);
+        }
+
+        return allTrue;
+    }
+
+    /**
+     * @brief  Invoke a function on each child Constraint
+     *
+     * This is a stricter version of the apply() function that will return
+     * immediately if any of the invokations of the callback function return
+     * \c false.
+     *
+     * @returns  \c true if all invokations of the callback function are
+     *           successful, \c false otherwise
+     */
+    bool applyStrict(ApplyFunction &applyFunction) const
+    {
+        for (const Constraint *constraint : m_constraints) {
+            if (!applyFunction(*constraint)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    bool getAlwaysInvalid() const
+    {
+        return m_alwaysInvalid;
+    }
+
+    /**
+     * @brief  Get the description associated with this sub-schema
+     *
+     * @throws  std::runtime_error if a description has not been set
+     *
+     * @returns  string containing sub-schema description
+     */
+    std::string getDescription() const
+    {
+        if (m_description) {
+            return *m_description;
+        }
+
+        throwRuntimeError("Schema does not have a description");
+    }
+
+    /**
+     * @brief  Get the ID associated with this sub-schema
+     *
+     * @throws  std::runtime_error if an ID has not been set
+     *
+     * @returns  string containing sub-schema ID
+     */
+    std::string getId() const
+    {
+        if (m_id) {
+            return *m_id;
+        }
+
+        throwRuntimeError("Schema does not have an ID");
+    }
+
+    /**
+     * @brief  Get the title associated with this sub-schema
+     *
+     * @throws  std::runtime_error if a title has not been set
+     *
+     * @returns  string containing sub-schema title
+     */
+    std::string getTitle() const
+    {
+        if (m_title) {
+            return *m_title;
+        }
+
+        throwRuntimeError("Schema does not have a title");
+    }
+
+    /**
+     * @brief  Check whether this sub-schema has a description
+     *
+     * @return boolean value
+     */
+    bool hasDescription() const
+    {
+        return static_cast<bool>(m_description);
+    }
+
+    /**
+     * @brief  Check whether this sub-schema has an ID
+     *
+     * @return  boolean value
+     */
+    bool hasId() const
+    {
+        return static_cast<bool>(m_id);
+    }
+
+    /**
+     * @brief  Check whether this sub-schema has a title
+     *
+     * @return  boolean value
+     */
+    bool hasTitle() const
+    {
+        return static_cast<bool>(m_title);
+    }
+
+    void setAlwaysInvalid(bool value)
+    {
+        m_alwaysInvalid = value;
+    }
+
+    /**
+     * @brief  Set the description for this sub-schema
+     *
+     * The description will not be used for validation, but may be used as part
+     * of the user interface for interacting with schemas and sub-schemas. As
+     * an example, it may be used as part of the validation error descriptions
+     * that are produced by the Validator and ValidationVisitor classes.
+     *
+     * @param  description  new description
+     */
+    void setDescription(const std::string &description)
+    {
+        m_description = description;
+    }
+
+    void setId(const std::string &id)
+    {
+        m_id = id;
+    }
+
+    /**
+     * @brief  Set the title for this sub-schema
+     *
+     * The title will not be used for validation, but may be used as part
+     * of the user interface for interacting with schemas and sub-schema. As an
+     * example, it may be used as part of the validation error descriptions
+     * that are produced by the Validator and ValidationVisitor classes.
+     *
+     * @param  title  new title
+     */
+    void setTitle(const std::string &title)
+    {
+        m_title = title;
+    }
+
+protected:
+
+    CustomAlloc m_allocFn;
+
+    CustomFree m_freeFn;
+
+private:
+
+    bool m_alwaysInvalid;
+
+    /// List of pointers to constraints that apply to this schema.
+    std::vector<const Constraint *> m_constraints;
+
+    /// Schema description (optional)
+    opt::optional<std::string> m_description;
+
+    /// Id to apply when resolving the schema URI
+    opt::optional<std::string> m_id;
+
+    /// Title string associated with the schema (optional)
+    opt::optional<std::string> m_title;
+};
+
+} // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/file_utils.hpp b/subprojects/valijson/include/valijson/utils/file_utils.hpp
new file mode 100644
index 000000000..92757cf64
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/file_utils.hpp
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <fstream>
+#include <limits>
+
+namespace valijson {
+namespace utils {
+
+/**
+ * Load a file into a string
+ *
+ * @param  path  path to the file to be loaded
+ * @param  dest  string into which file should be loaded
+ *
+ * @return  true if loaded, false otherwise
+ */
+inline bool loadFile(const std::string &path, std::string &dest)
+{
+    // Open file for reading
+    std::ifstream file(path.c_str());
+    if (!file.is_open()) {
+        return false;
+    }
+
+    // Allocate space for file contents
+    file.seekg(0, std::ios::end);
+    const std::streamoff offset = file.tellg();
+    if (offset < 0 || offset > std::numeric_limits<unsigned int>::max()) {
+        return false;
+    }
+
+    dest.clear();
+    dest.reserve(static_cast<unsigned int>(offset));
+
+    // Assign file contents to destination string
+    file.seekg(0, std::ios::beg);
+    dest.assign(std::istreambuf_iterator<char>(file),
+                std::istreambuf_iterator<char>());
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/json11_utils.hpp b/subprojects/valijson/include/valijson/utils/json11_utils.hpp
new file mode 100644
index 000000000..b20b47854
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/json11_utils.hpp
@@ -0,0 +1,34 @@
+#pragma once
+
+#include <iostream>
+
+#include <json11.hpp>
+
+#include <valijson/utils/file_utils.hpp>
+
+namespace valijson {
+namespace utils {
+
+inline bool loadDocument(const std::string &path, json11::Json &document)
+{
+    // Load schema JSON from file
+    std::string file;
+    if (!loadFile(path, file)) {
+        std::cerr << "Failed to load json from file '" << path << "'." << std::endl;
+        return false;
+    }
+
+    // Parse schema
+    std::string err;
+    document = json11::Json::parse(file, err);
+    if (!err.empty()) {
+        std::cerr << "json11 failed to parse the document:" << std::endl
+                  << "Parse error: " << err << std::endl;
+        return false;
+    }
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/jsoncpp_utils.hpp b/subprojects/valijson/include/valijson/utils/jsoncpp_utils.hpp
new file mode 100644
index 000000000..49a43b624
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/jsoncpp_utils.hpp
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <iostream>
+#include <string>
+#include <memory>
+
+#include <json/json.h>
+
+#include <valijson/utils/file_utils.hpp>
+
+namespace valijson {
+namespace utils {
+
+inline bool loadDocument(const std::string &path, Json::Value &document)
+{
+    // Load schema JSON from file
+    std::string file;
+    if (!loadFile(path, file)) {
+        std::cerr << "Failed to load json from file '" << path << "'." << std::endl;
+        return false;
+    }
+
+    const auto fileLength = static_cast<int>(file.length());
+    Json::CharReaderBuilder builder;
+    const std::unique_ptr<Json::CharReader> reader(builder.newCharReader());
+    std::string err;
+    if (!reader->parse(file.c_str(), file.c_str() + fileLength, &document, &err)) {
+        std::cerr << "Jsoncpp parser failed to parse the document:" << std::endl << err;
+        return false;
+    }
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/nlohmann_json_utils.hpp b/subprojects/valijson/include/valijson/utils/nlohmann_json_utils.hpp
new file mode 100644
index 000000000..b3cbe205b
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/nlohmann_json_utils.hpp
@@ -0,0 +1,43 @@
+#pragma once
+
+#include <iostream>
+
+#include <nlohmann/json.hpp>
+#include <valijson/utils/file_utils.hpp>
+#include <valijson/exceptions.hpp>
+
+namespace valijson {
+namespace utils {
+
+inline bool loadDocument(const std::string &path, nlohmann::json &document)
+{
+    // Load schema JSON from file
+    std::string file;
+    if (!loadFile(path, file)) {
+        std::cerr << "Failed to load json from file '" << path << "'."
+                  << std::endl;
+        return false;
+    }
+
+    // Parse schema
+#if VALIJSON_USE_EXCEPTION
+    try {
+        document = nlohmann::json::parse(file);
+    } catch (std::invalid_argument const& exception) {
+        std::cerr << "nlohmann::json failed to parse the document\n"
+            << "Parse error:" << exception.what() << "\n";
+        return false;
+    }
+#else
+    document = nlohmann::json::parse(file, nullptr, false);
+    if (document.is_discarded()) {
+        std::cerr << "nlohmann::json failed to parse the document.";
+        return false;
+    }
+#endif
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/picojson_utils.hpp b/subprojects/valijson/include/valijson/utils/picojson_utils.hpp
new file mode 100644
index 000000000..36420d2e0
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/picojson_utils.hpp
@@ -0,0 +1,39 @@
+#pragma once
+
+#include <iostream>
+
+#ifdef _MSC_VER
+#pragma warning(disable: 4706)
+#include <picojson.h>
+#pragma warning(default: 4706)
+#else
+#include <picojson.h>
+#endif
+
+#include <valijson/utils/file_utils.hpp>
+
+namespace valijson {
+namespace utils {
+
+inline bool loadDocument(const std::string &path, picojson::value &document)
+{
+    // Load schema JSON from file
+    std::string file;
+    if (!loadFile(path, file)) {
+        std::cerr << "Failed to load json from file '" << path << "'." << std::endl;
+        return false;
+    }
+
+    // Parse schema
+    std::string err = picojson::parse(document, file);
+    if (!err.empty()) {
+        std::cerr << "PicoJson failed to parse the document:" << std::endl
+                  << "Parse error: " << err << std::endl;
+        return false;
+    }
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/poco_json_utils.hpp b/subprojects/valijson/include/valijson/utils/poco_json_utils.hpp
new file mode 100644
index 000000000..145cec346
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/poco_json_utils.hpp
@@ -0,0 +1,37 @@
+#pragma once
+
+#include <iostream>
+
+#include <Poco/JSON/JSONException.h>
+#include <Poco/JSON/Object.h>
+#include <Poco/JSON/Parser.h>
+
+#include <valijson/utils/file_utils.hpp>
+
+namespace valijson {
+namespace utils {
+
+inline bool loadDocument(const std::string &path, Poco::Dynamic::Var &document)
+{
+    // Load schema JSON from file
+    std::string file;
+    if (!loadFile(path, file)) {
+        std::cerr << "Failed to load json from file '" << path << "'."
+                  << std::endl;
+        return false;
+    }
+
+    // Parse schema
+    try {
+        document = Poco::JSON::Parser().parse(file);
+    } catch (Poco::Exception const& exception) {
+        std::cerr << "Poco::JSON failed to parse the document\n"
+            << "Parse error:" << exception.what() << "\n";
+        return false;
+    }
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/property_tree_utils.hpp b/subprojects/valijson/include/valijson/utils/property_tree_utils.hpp
new file mode 100644
index 000000000..2317f127c
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/property_tree_utils.hpp
@@ -0,0 +1,74 @@
+#pragma once
+
+#include <iostream>
+#include <sstream>
+
+#include <boost/property_tree/ptree.hpp>
+#include <boost/throw_exception.hpp>
+
+#if defined(__clang__)
+# pragma clang diagnostic push
+# pragma clang diagnostic ignored "-Wshadow"
+# include <boost/property_tree/json_parser.hpp>
+# pragma clang diagnostic pop
+#else
+# include <boost/property_tree/json_parser.hpp>
+#endif
+
+// Source locations were added in boost 1.73.
+#include <boost/version.hpp>
+#if (BOOST_VERSION > 107300)
+#include <boost/assert/source_location.hpp>
+#endif
+
+#include <valijson/utils/file_utils.hpp>
+#include <valijson/exceptions.hpp>
+
+#if !VALIJSON_USE_EXCEPTION
+
+namespace boost {
+
+// Boost requires used-defined exception throwers when exceptions are
+// disabled.
+// NOTE: BOOST_NORETURN attribute was added in 1.71.
+#if (BOOST_VERSION >= 107100)
+BOOST_NORETURN
+#endif
+void throw_exception(std::exception const & e ) {
+ valijson::throwRuntimeError(e.what());
+}
+
+// Source location override was added in 1.73.
+#if (BOOST_VERSION >= 107300)
+BOOST_NORETURN
+void throw_exception(std::exception const & e, boost::source_location const & loc ) {
+  valijson::throwRuntimeError(e.what());
+}
+#endif
+
+}  // namespace boost
+
+#endif
+
+namespace valijson {
+namespace utils {
+
+inline bool loadDocument(const std::string &path, boost::property_tree::ptree &document)
+{
+#if !defined(BOOST_NO_EXCEPTIONS)
+    try {
+#endif
+        boost::property_tree::read_json(path, document);
+#if !defined(BOOST_NO_EXCEPTIONS)
+    } catch (std::exception &e) {
+        std::cerr << "Boost Property Tree JSON parser failed to parse the document:" << std::endl;
+        std::cerr << e.what() << std::endl;
+        return false;
+    }
+#endif
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/qtjson_utils.hpp b/subprojects/valijson/include/valijson/utils/qtjson_utils.hpp
new file mode 100644
index 000000000..c05b0f0b6
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/qtjson_utils.hpp
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <QFile>
+
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QJsonArray>
+
+#include <valijson/utils/file_utils.hpp>
+
+namespace valijson {
+namespace utils {
+
+inline bool loadDocument(const std::string &path, QJsonValue &root)
+{
+    // Load schema JSON from file
+    QFile file(QString::fromStdString(path));
+    if (!file.open(QFile::ReadOnly)) {
+        std::cerr << "Failed to load json from file '" << path << "'." << std::endl;
+        return false;
+    }
+
+    QByteArray data = file.readAll();
+
+    // Parse schema
+    QJsonParseError parseError;
+    QJsonDocument doc = QJsonDocument::fromJson(data);
+    if (doc.isNull()) {
+        std::cerr << "qt failed to parse the document:" << std::endl
+                  << parseError.errorString().toStdString() << std::endl;
+        return false;
+    } else if (doc.isObject()) {
+        root = QJsonValue(doc.object());
+    } else if (doc.isArray()) {
+        root = QJsonValue(doc.array());
+    } else if (doc.isEmpty()) {
+        root = QJsonValue();
+    }
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/rapidjson_utils.hpp b/subprojects/valijson/include/valijson/utils/rapidjson_utils.hpp
new file mode 100644
index 000000000..2f90ba933
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/rapidjson_utils.hpp
@@ -0,0 +1,46 @@
+#pragma once
+
+#include <iostream>
+#include <stdexcept>
+
+#include <rapidjson/document.h>
+
+#include <valijson/utils/file_utils.hpp>
+
+namespace valijson {
+namespace utils {
+
+template<typename Encoding, typename Allocator>
+inline bool loadDocument(const std::string &path, rapidjson::GenericDocument<Encoding, Allocator> &document)
+{
+    // Load schema JSON from file
+    std::string file;
+    if (!loadFile(path, file)) {
+        std::cerr << "Failed to load json from file '" << path << "'." << std::endl;
+        return false;
+    }
+
+    // Parse schema
+#if VALIJSON_USE_EXCEPTIONS
+    try {
+#endif
+        document.template Parse<rapidjson::kParseIterativeFlag>(file.c_str());
+        if (document.HasParseError()) {
+            std::cerr << "RapidJson failed to parse the document:" << std::endl;
+            std::cerr << "Parse error: " << document.GetParseError() << std::endl;
+            std::cerr << "Near: " << file.substr((std::max)(size_t(0), document.GetErrorOffset() - 20), 40) << std::endl;
+            return false;
+        }
+#if VALIJSON_USE_EXCEPTIONS
+    } catch (const std::runtime_error &e) {
+        std::cerr << "RapidJson failed to parse the document:" << std::endl;
+        std::cerr << "Runtime error: " << e.what() << std::endl;
+        return false;
+    }
+#endif
+
+    return true;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/utils/utf8_utils.hpp b/subprojects/valijson/include/valijson/utils/utf8_utils.hpp
new file mode 100644
index 000000000..f1e01a547
--- /dev/null
+++ b/subprojects/valijson/include/valijson/utils/utf8_utils.hpp
@@ -0,0 +1,63 @@
+#pragma once
+
+#include <assert.h>
+#include <stdexcept>
+#include <string>
+
+#include <valijson/exceptions.hpp>
+
+/*
+  Basic UTF-8 manipulation routines, adapted from code that was released into
+  the public domain by Jeff Bezanson.
+*/
+
+namespace valijson {
+namespace utils {
+
+static const uint32_t offsetsFromUTF8[6] = {
+    0x00000000UL, 0x00003080UL, 0x000E2080UL,
+    0x03C82080UL, 0xFA082080UL, 0x82082080UL
+};
+
+/* is c the start of a utf8 sequence? */
+inline bool isutf(char c) {
+    return ((c & 0xC0) != 0x80);
+}
+
+/* reads the next utf-8 sequence out of a string, updating an index */
+inline uint64_t u8_nextchar(const char *s, uint64_t *i)
+{
+    uint64_t ch = 0;
+    int sz = 0;
+
+    do {
+        ch <<= 6;
+        ch += static_cast<unsigned char>(s[(*i)++]);
+        sz++;
+    } while (s[*i] && !isutf(s[*i]));
+    ch -= offsetsFromUTF8[sz-1];
+
+    return ch;
+}
+
+/* number of characters */
+inline uint64_t u8_strlen(const char *s)
+{
+    constexpr auto maxLength = std::numeric_limits<uint64_t>::max();
+    uint64_t count = 0;
+    uint64_t i = 0;
+
+    while (s[i] != 0 && u8_nextchar(s, &i) != 0) {
+        if (i == maxLength) {
+            throwRuntimeError(
+                    "String exceeded maximum size of " +
+                    std::to_string(maxLength) + " bytes.");
+        }
+        count++;
+    }
+
+    return count;
+}
+
+}  // namespace utils
+}  // namespace valijson
diff --git a/subprojects/valijson/include/valijson/validation_results.hpp b/subprojects/valijson/include/valijson/validation_results.hpp
new file mode 100644
index 000000000..b82131793
--- /dev/null
+++ b/subprojects/valijson/include/valijson/validation_results.hpp
@@ -0,0 +1,107 @@
+#pragma once
+
+#include <deque>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace valijson {
+
+/**
+ * @brief  Class that encapsulates the storage of validation errors.
+ *
+ * This class maintains an internal FIFO queue of errors that are reported
+ * during validation. Errors are pushed on to the back of an internal
+ * queue, and can retrieved by popping them from the front of the queue.
+ */
+class ValidationResults
+{
+public:
+
+    /**
+     * @brief  Describes a validation error.
+     *
+     * This struct is used to pass around the context and description of a
+     * validation error.
+     */
+    struct Error
+    {
+        /// Path to the node that failed validation.
+        std::vector<std::string> context;
+
+        /// A detailed description of the validation error.
+        std::string description;
+    };
+
+    /**
+     * @brief  Return begin iterator for results in the queue.
+     */
+    std::deque<Error>::const_iterator begin() const
+    {
+        return m_errors.begin();
+    }
+
+    /**
+     * @brief  Return end iterator for results in the queue.
+     */
+    std::deque<Error>::const_iterator end() const
+    {
+        return m_errors.end();
+    }
+
+    /**
+     * @brief  Return the number of errors in the queue.
+     */
+    size_t numErrors() const
+    {
+        return m_errors.size();
+    }
+
+    /**
+     * @brief  Copy an Error and push it on to the back of the queue.
+     *
+     * @param  error  Reference to an Error object to be copied.
+     */
+    void pushError(const Error &error)
+    {
+        m_errors.push_back(error);
+    }
+
+    /**
+     * @brief  Push an error onto the back of the queue.
+     *
+     * @param  context      Context of the validation error.
+     * @param  description  Description of the validation error.
+     */
+    void
+    pushError(const std::vector<std::string> &context, const std::string &description)
+    {
+        m_errors.push_back({context, description});
+    }
+
+    /**
+     * @brief  Pop an error from the front of the queue.
+     *
+     * @param  error  Reference to an Error object to populate.
+     *
+     * @returns  true if an Error was popped, false otherwise.
+     */
+    bool
+    popError(Error &error)
+    {
+        if (m_errors.empty()) {
+            return false;
+        }
+
+        error = m_errors.front();
+        m_errors.pop_front();
+        return true;
+    }
+
+private:
+
+    /// FIFO queue of validation errors that have been reported
+    std::deque<Error> m_errors;
+};
+
+} // namespace valijson
diff --git a/subprojects/valijson/include/valijson/validation_visitor.hpp b/subprojects/valijson/include/valijson/validation_visitor.hpp
new file mode 100644
index 000000000..cd4442d7c
--- /dev/null
+++ b/subprojects/valijson/include/valijson/validation_visitor.hpp
@@ -0,0 +1,1792 @@
+#pragma once
+
+#include <cmath>
+#include <string>
+#include <regex>
+#include <unordered_map>
+
+#include <valijson/adapters/std_string_adapter.hpp>
+#include <valijson/constraints/concrete_constraints.hpp>
+#include <valijson/constraints/constraint_visitor.hpp>
+#include <utility>
+#include <valijson/validation_results.hpp>
+
+#include <valijson/utils/utf8_utils.hpp>
+
+#ifdef _MSC_VER
+#pragma warning( push )
+#pragma warning( disable : 4702 )
+#endif
+
+namespace valijson {
+
+class ValidationResults;
+
+/**
+ * @brief   Implementation of the ConstraintVisitor interface that validates a
+ *          target document
+ *
+ * @tparam  AdapterType  Adapter type for the target document.
+ */
+template<typename AdapterType>
+class ValidationVisitor: public constraints::ConstraintVisitor
+{
+public:
+
+    /**
+     * @brief  Construct a new validator for a given target value and context.
+     *
+     * @param  target       Target value to be validated
+     * @param  context      Current context for validation error descriptions,
+     *                      only used if results is set.
+     * @param  strictTypes  Use strict type comparison
+     * @param  results      Optional pointer to ValidationResults object, for
+     *                      recording error descriptions. If this pointer is set
+     *                      to nullptr, validation errors will caused validation to
+     *                      stop immediately.
+     * @param  regexesCache Cache of already created std::regex objects for pattern
+     *                      constraints.
+     */
+    ValidationVisitor(const AdapterType &target,
+                      std::vector<std::string> context,
+                      const bool strictTypes,
+                      ValidationResults *results,
+                      std::unordered_map<std::string, std::regex>& regexesCache)
+      : m_target(target),
+        m_context(std::move(context)),
+        m_results(results),
+        m_strictTypes(strictTypes),
+        m_regexesCache(regexesCache) { }
+
+    /**
+     * @brief  Validate the target against a schema.
+     *
+     * When a ValidationResults object has been set via the 'results' member
+     * variable, validation will proceed as long as no fatal errors occur,
+     * with error descriptions added to the ValidationResults object.
+     *
+     * If a pointer to a ValidationResults instance is not provided, validation
+     * will only continue for as long as the constraints are validated
+     * successfully.
+     *
+     * @param   subschema  Sub-schema that the target must validate against
+     *
+     * @return  \c true if validation passes; \c false otherwise
+     */
+    bool validateSchema(const Subschema &subschema)
+    {
+        if (subschema.getAlwaysInvalid()) {
+            return false;
+        }
+
+        // Wrap the validationCallback() function below so that it will be
+        // passed a reference to a constraint (_1), and a reference to the
+        // visitor (*this).
+        Subschema::ApplyFunction fn(std::bind(validationCallback, std::placeholders::_1, std::ref(*this)));
+
+        // Perform validation against each constraint defined in the schema
+        if (m_results == nullptr) {
+            // The applyStrict() function will return immediately if the
+            // callback function returns false
+            if (!subschema.applyStrict(fn)) {
+                return false;
+            }
+        } else {
+            // The apply() function will iterate over all constraints in the
+            // schema, even if the callback function returns false. Once
+            // iteration is complete, the apply() function will return true
+            // only if all invokations of the callback function returned true.
+            if (!subschema.apply(fn)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief  Validate a value against an AllOfConstraint
+     *
+     * An allOf constraint provides a set of child schemas against which the
+     * target must be validated in order for the constraint to the satifisfied.
+     *
+     * When a ValidationResults object has been set via the 'results' member
+     * variable, validation will proceed as long as no fatal errors occur,
+     * with error descriptions added to the ValidationResults object.
+     *
+     * If a pointer to a ValidationResults instance is not provided, validation
+     * will only continue for as long as the child schemas are validated
+     * successfully.
+     *
+     * @param  constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if validation passes; \c false otherwise
+     */
+    bool visit(const AllOfConstraint &constraint) override
+    {
+        bool validated = true;
+        constraint.applyToSubschemas(
+                ValidateSubschemas(m_target, m_context, true, false, *this, m_results, nullptr, &validated));
+
+        return validated;
+    }
+
+    /**
+     * @brief   Validate a value against an AnyOfConstraint
+     *
+     * An anyOf constraint provides a set of child schemas, any of which the
+     * target may be validated against in order for the constraint to the
+     * satifisfied.
+     *
+     * Because an anyOf constraint does not require the target to validate
+     * against all child schemas, if validation against a single schema fails,
+     * the results will not be added to a ValidationResults object. Only if
+     * validation fails for all child schemas will an error be added to the
+     * ValidationResults object.
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if validation passes; \c false otherwise
+     */
+    bool visit(const AnyOfConstraint &constraint) override
+    {
+        unsigned int numValidated = 0;
+
+        ValidationResults newResults;
+        ValidationResults *childResults = (m_results) ? &newResults : nullptr;
+
+        ValidationVisitor<AdapterType> v(m_target, m_context, m_strictTypes, childResults, m_regexesCache);
+        constraint.applyToSubschemas(
+                ValidateSubschemas(m_target, m_context, false, true, v, childResults, &numValidated, nullptr));
+
+        if (numValidated == 0 && m_results) {
+            ValidationResults::Error childError;
+            while (childResults->popError(childError)) {
+                m_results->pushError( childError.context, childError.description);
+            }
+            m_results->pushError(m_context, "Failed to validate against any schemas allowed by anyOf constraint.");
+        }
+
+        return numValidated > 0;
+    }
+
+    /**
+     * @brief   Validate current node using a set of 'if', 'then' and 'else' subschemas
+     *
+     * A conditional constraint allows a document to be validated against one of two additional
+     * subschemas (specified via 'then' or 'else' properties) depending on whether the document
+     * satifies an optional subschema (specified via the 'if' property).
+     *
+     * @param   constraint  ConditionalConstraint that the current node must validate against
+     *
+     * @return  \c true if validation passes; \c false otherwise
+     */
+    bool visit(const ConditionalConstraint &constraint) override
+    {
+        ValidationResults newResults;
+        ValidationResults* conditionalResults = (m_results) ? &newResults : nullptr;
+
+        // Create a validator to evaluate the conditional
+        ValidationVisitor ifValidator(m_target, m_context, m_strictTypes, nullptr, m_regexesCache);
+        ValidationVisitor thenElseValidator(m_target, m_context, m_strictTypes, conditionalResults, m_regexesCache);
+
+        bool validated = false;
+        if (ifValidator.validateSchema(*constraint.getIfSubschema())) {
+            const Subschema *thenSubschema = constraint.getThenSubschema();
+            validated = thenSubschema == nullptr || thenElseValidator.validateSchema(*thenSubschema);
+        } else {
+            const Subschema *elseSubschema = constraint.getElseSubschema();
+            validated = elseSubschema == nullptr || thenElseValidator.validateSchema(*elseSubschema);
+        }
+
+        if (!validated && m_results) {
+            ValidationResults::Error conditionalError;
+            while (conditionalResults->popError(conditionalError)) {
+                m_results->pushError(conditionalError.context, conditionalError.description);
+            }
+            m_results->pushError(m_context, "Failed to validate against a conditional schema set by if-then-else constraints.");
+        }
+
+        return validated;
+    }
+
+    /**
+     * @brief   Validate current node using a 'const' constraint
+     *
+     * A const constraint allows a document to be validated against a specific value.
+     *
+     * @param   constraint  ConstConstraint that the current node must validate against
+     *
+     * @return  \c true if validation passes; \f false otherwise
+     */
+    bool visit(const ConstConstraint &constraint) override
+    {
+        if (!constraint.getValue()->equalTo(m_target, m_strictTypes)) {
+            if (m_results) {
+                m_results->pushError(m_context, "Failed to match expected value set by 'const' constraint.");
+            }
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief  Validate current node using a 'contains' constraint
+     *
+     * A contains constraint is satisfied if the target is not an array, or if it is an array,
+     * only if it contains at least one value that matches the specified schema.
+     *
+     * @param   constraint  ContainsConstraint that the current node must validate against
+     *
+     * @return  \c true if validation passes; \c false otherwise
+     */
+    bool visit(const ContainsConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isArray()) || !m_target.maybeArray()) {
+            return true;
+        }
+
+        const Subschema *subschema = constraint.getSubschema();
+        const typename AdapterType::Array arr = m_target.asArray();
+
+        bool validated = false;
+        for (const auto &el : arr) {
+            ValidationVisitor containsValidator(el, m_context, m_strictTypes, nullptr, m_regexesCache);
+            if (containsValidator.validateSchema(*subschema)) {
+                validated = true;
+                break;
+            }
+        }
+
+        if (!validated) {
+            if (m_results) {
+                m_results->pushError(m_context, "Failed to any values against subschema in 'contains' constraint.");
+            }
+
+            return false;
+        }
+
+        return validated;
+    }
+
+    /**
+     * @brief   Validate current node against a 'dependencies' constraint
+     *
+     * A 'dependencies' constraint can be used to specify property-based or
+     * schema-based dependencies that must be fulfilled when a particular
+     * property is present in an object.
+     *
+     * Property-based dependencies define a set of properties that must be
+     * present in addition to a particular property, whereas a schema-based
+     * dependency defines an additional schema that the current document must
+     * validate against.
+     *
+     * @param   constraint  DependenciesConstraint that the current node
+     *                      must validate against
+     *
+     * @return  \c true if validation passes; \c false otherwise
+     */
+    bool visit(const DependenciesConstraint &constraint) override
+    {
+        // Ignore non-objects
+        if ((m_strictTypes && !m_target.isObject()) || (!m_target.maybeObject())) {
+            return true;
+        }
+
+        // Object to be validated
+        const typename AdapterType::Object object = m_target.asObject();
+
+        // Cleared if validation fails
+        bool validated = true;
+
+        // Iterate over all dependent properties defined by this constraint,
+        // invoking the DependentPropertyValidator functor once for each
+        // set of dependent properties
+        constraint.applyToPropertyDependencies(ValidatePropertyDependencies(object, m_context, m_results, &validated));
+        if (!m_results && !validated) {
+            return false;
+        }
+
+        // Iterate over all dependent schemas defined by this constraint,
+        // invoking the DependentSchemaValidator function once for each schema
+        // that must be validated if a given property is present
+        constraint.applyToSchemaDependencies(ValidateSchemaDependencies(
+                object, m_context, *this, m_results, &validated));
+        if (!m_results && !validated) {
+            return false;
+        }
+
+        return validated;
+    }
+
+    /**
+     * @brief   Validate current node against an EnumConstraint
+     *
+     * Validation succeeds if the target is equal to one of the values provided
+     * by the EnumConstraint.
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if validation succeeds; \c false otherwise
+     */
+    bool visit(const EnumConstraint &constraint) override
+    {
+        unsigned int numValidated = 0;
+        constraint.applyToValues(
+                ValidateEquality(m_target, m_context, false, true, m_strictTypes, nullptr, &numValidated));
+
+        if (numValidated == 0) {
+            if (m_results) {
+                m_results->pushError(m_context, "Failed to match against any enum values.");
+            }
+
+            return false;
+        }
+
+        return numValidated > 0;
+    }
+
+    /**
+     * @brief   Validate a value against a LinearItemsConstraint
+     *
+     * A LinearItemsConstraint represents an 'items' constraint that specifies,
+     * for each item in array, an individual sub-schema that the item must
+     * validate against. The LinearItemsConstraint class also captures the
+     * presence of an 'additionalItems' constraint, which specifies a default
+     * sub-schema that should be used if an array contains more items than
+     * there are sub-schemas in the 'items' constraint.
+     *
+     * If the current value is not an array, validation always succeeds.
+     *
+     * @param  constraint  SingularItemsConstraint to validate against
+     *
+     * @returns  \c true if validation is successful; \c false otherwise
+     */
+    bool visit(const LinearItemsConstraint &constraint) override
+    {
+        // Ignore values that are not arrays
+        if ((m_strictTypes && !m_target.isArray()) || (!m_target.maybeArray())) {
+            return true;
+        }
+
+        // Sub-schema to validate against when number of items in array exceeds
+        // the number of sub-schemas provided by the 'items' constraint
+        const Subschema * const additionalItemsSubschema = constraint.getAdditionalItemsSubschema();
+
+        // Track how many items are validated using 'items' constraint
+        unsigned int numValidated = 0;
+
+        // Array to validate
+        const typename AdapterType::Array arr = m_target.asArray();
+        const size_t arrSize = arr.size();
+
+        // Track validation status
+        bool validated = true;
+
+        // Validate as many items as possible using 'items' sub-schemas
+        const size_t itemSubschemaCount = constraint.getItemSubschemaCount();
+        if (itemSubschemaCount > 0) {
+            if (!additionalItemsSubschema) {
+                if (arrSize > itemSubschemaCount) {
+                    if (!m_results) {
+                        return false;
+                    }
+                    m_results->pushError(m_context, "Array contains more items than allowed by items constraint.");
+                    validated = false;
+                }
+            }
+
+            constraint.applyToItemSubschemas(
+                    ValidateItems(arr, m_context, true, m_results != nullptr, m_strictTypes, m_results, &numValidated,
+                            &validated, m_regexesCache));
+
+            if (!m_results && !validated) {
+                return false;
+            }
+        }
+
+        // Validate remaining items using 'additionalItems' sub-schema
+        if (numValidated < arrSize) {
+            if (additionalItemsSubschema) {
+                // Begin validation from the first item not validated against
+                // an sub-schema provided by the 'items' constraint
+                unsigned int index = numValidated;
+                typename AdapterType::Array::const_iterator begin = arr.begin();
+                begin.advance(numValidated);
+                for (typename AdapterType::Array::const_iterator itr = begin;
+                        itr != arr.end(); ++itr) {
+
+                    // Update context for current array item
+                    std::vector<std::string> newContext = m_context;
+                    newContext.push_back("[" + std::to_string(index) + "]");
+
+                    ValidationVisitor<AdapterType> validator(*itr, newContext, m_strictTypes, m_results, m_regexesCache);
+
+                    if (!validator.validateSchema(*additionalItemsSubschema)) {
+                        if (m_results) {
+                            m_results->pushError(m_context, "Failed to validate item #" + std::to_string(index) +
+                                    " against additional items schema.");
+                            validated = false;
+                        } else {
+                            return false;
+                        }
+                    }
+
+                    index++;
+                }
+
+            } else if (m_results) {
+                m_results->pushError(m_context, "Cannot validate item #" + std::to_string(numValidated) +
+                        " or greater using 'items' constraint or 'additionalItems' constraint.");
+                validated = false;
+
+            } else {
+                return false;
+            }
+        }
+
+        return validated;
+    }
+
+    /**
+     * @brief   Validate a value against a MaximumConstraint object
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if constraints are satisfied; \c false otherwise
+     */
+    bool visit(const MaximumConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isNumber()) || !m_target.maybeDouble()) {
+            // Ignore values that are not numbers
+            return true;
+        }
+
+        const double maximum = constraint.getMaximum();
+
+        if (constraint.getExclusiveMaximum()) {
+            if (m_target.asDouble() >= maximum) {
+                if (m_results) {
+                    m_results->pushError(m_context, "Expected number less than " + std::to_string(maximum));
+                }
+
+                return false;
+            }
+
+        } else if (m_target.asDouble() > maximum) {
+            if (m_results) {
+                m_results->pushError(m_context, "Expected number less than or equal to " + std::to_string(maximum));
+            }
+
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a MaxItemsConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MaxItemsConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isArray()) || !m_target.maybeArray()) {
+            return true;
+        }
+
+        const uint64_t maxItems = constraint.getMaxItems();
+        if (m_target.asArray().size() <= maxItems) {
+            return true;
+        }
+
+        if (m_results) {
+            m_results->pushError(m_context, "Array should contain no more than " + std::to_string(maxItems) +
+                    " elements.");
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Validate a value against a MaxLengthConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MaxLengthConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isString()) || !m_target.maybeString()) {
+            return true;
+        }
+
+        const std::string s = m_target.asString();
+        const uint64_t len = utils::u8_strlen(s.c_str());
+        const uint64_t maxLength = constraint.getMaxLength();
+        if (len <= maxLength) {
+            return true;
+        }
+
+        if (m_results) {
+            m_results->pushError(m_context, "String should be no more than " + std::to_string(maxLength) +
+                    " characters in length.");
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Validate a value against a MaxPropertiesConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MaxPropertiesConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isObject()) || !m_target.maybeObject()) {
+            return true;
+        }
+
+        const uint64_t maxProperties = constraint.getMaxProperties();
+
+        if (m_target.asObject().size() <= maxProperties) {
+            return true;
+        }
+
+        if (m_results) {
+            m_results->pushError(m_context, "Object should have no more than " + std::to_string(maxProperties) +
+                    " properties.");
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Validate a value against a MinimumConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MinimumConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isNumber()) || !m_target.maybeDouble()) {
+            // Ignore values that are not numbers
+            return true;
+        }
+
+        const double minimum = constraint.getMinimum();
+
+        if (constraint.getExclusiveMinimum()) {
+            if (m_target.asDouble() <= minimum) {
+                if (m_results) {
+                    m_results->pushError(m_context, "Expected number greater than " + std::to_string(minimum));
+                }
+
+                return false;
+            }
+        } else if (m_target.asDouble() < minimum) {
+            if (m_results) {
+                m_results->pushError(m_context, "Expected number greater than or equal to " + std::to_string(minimum));
+            }
+
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a MinItemsConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MinItemsConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isArray()) || !m_target.maybeArray()) {
+            return true;
+        }
+
+        const uint64_t minItems = constraint.getMinItems();
+        if (m_target.asArray().size() >= minItems) {
+            return true;
+        }
+
+        if (m_results) {
+            m_results->pushError(m_context, "Array should contain no fewer than " + std::to_string(minItems) +
+                    " elements.");
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Validate a value against a MinLengthConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MinLengthConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isString()) || !m_target.maybeString()) {
+            return true;
+        }
+
+        const std::string s = m_target.asString();
+        const uint64_t len = utils::u8_strlen(s.c_str());
+        const uint64_t minLength = constraint.getMinLength();
+        if (len >= minLength) {
+            return true;
+        }
+
+        if (m_results) {
+            m_results->pushError(m_context, "String should be no fewer than " + std::to_string(minLength) +
+                    " characters in length.");
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Validate a value against a MinPropertiesConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MinPropertiesConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isObject()) || !m_target.maybeObject()) {
+            return true;
+        }
+
+        const uint64_t minProperties = constraint.getMinProperties();
+
+        if (m_target.asObject().size() >= minProperties) {
+            return true;
+        }
+
+        if (m_results) {
+            m_results->pushError(m_context, "Object should have no fewer than " + std::to_string(minProperties) +
+                    " properties.");
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Validate a value against a MultipleOfDoubleConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MultipleOfDoubleConstraint &constraint) override
+    {
+        const double divisor = constraint.getDivisor();
+
+        double d = 0.;
+        if (m_target.maybeDouble()) {
+            if (!m_target.asDouble(d)) {
+                if (m_results) {
+                    m_results->pushError(m_context, "Value could not be converted "
+                            "to a number to check if it is a multiple of " + std::to_string(divisor));
+                }
+                return false;
+            }
+        } else if (m_target.maybeInteger()) {
+            int64_t i = 0;
+            if (!m_target.asInteger(i)) {
+                if (m_results) {
+                    m_results->pushError(m_context, "Value could not be converted "
+                            "to a number to check if it is a multiple of " + std::to_string(divisor));
+                }
+                return false;
+            }
+            d = static_cast<double>(i);
+        } else {
+            return true;
+        }
+
+        if (d == 0) {
+            return true;
+        }
+
+        const double r = remainder(d, divisor);
+
+        if (fabs(r) > std::numeric_limits<double>::epsilon()) {
+            if (m_results) {
+                m_results->pushError(m_context, "Value should be a multiple of " + std::to_string(divisor));
+            }
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a MultipleOfIntConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const MultipleOfIntConstraint &constraint) override
+    {
+        const int64_t divisor = constraint.getDivisor();
+
+        int64_t i = 0;
+        if (m_target.maybeInteger()) {
+            if (!m_target.asInteger(i)) {
+                if (m_results) {
+                    m_results->pushError(m_context, "Value could not be converted to an integer for multipleOf check");
+                }
+                return false;
+            }
+        } else if (m_target.maybeDouble()) {
+            double d;
+            if (!m_target.asDouble(d)) {
+                if (m_results) {
+                    m_results->pushError(m_context, "Value could not be converted to a double for multipleOf check");
+                }
+                return false;
+            }
+            i = static_cast<int64_t>(d);
+        } else {
+            return true;
+        }
+
+        if (i == 0) {
+            return true;
+        }
+
+        if (i % divisor != 0) {
+            if (m_results) {
+                m_results->pushError(m_context, "Value should be a multiple of " + std::to_string(divisor));
+            }
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a NotConstraint
+     *
+     * If the subschema NotConstraint currently holds a nullptr, the
+     * schema will be treated like the empty schema. Therefore validation
+     * will always fail.
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const NotConstraint &constraint) override
+    {
+        const Subschema *subschema = constraint.getSubschema();
+        if (!subschema) {
+            // Treat nullptr like empty schema
+            return false;
+        }
+
+        ValidationVisitor<AdapterType> v(m_target, m_context, m_strictTypes, nullptr, m_regexesCache);
+        if (v.validateSchema(*subschema)) {
+            if (m_results) {
+                m_results->pushError(m_context,
+                        "Target should not validate against schema specified in 'not' constraint.");
+            }
+
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a OneOfConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const OneOfConstraint &constraint) override
+    {
+        unsigned int numValidated = 0;
+
+        ValidationResults newResults;
+        ValidationResults *childResults = (m_results) ? &newResults : nullptr;
+
+        ValidationVisitor<AdapterType> v(m_target, m_context, m_strictTypes, childResults, m_regexesCache);
+        constraint.applyToSubschemas(
+                ValidateSubschemas(m_target, m_context, true, true, v, childResults, &numValidated, nullptr));
+
+        if (numValidated == 0) {
+            if (m_results) {
+                ValidationResults::Error childError;
+                while (childResults->popError(childError)) {
+                    m_results->pushError(
+                            childError.context,
+                            childError.description);
+                }
+                m_results->pushError(m_context, "Failed to validate against any "
+                        "child schemas allowed by oneOf constraint.");
+            }
+            return false;
+        } else if (numValidated != 1) {
+            if (m_results) {
+                m_results->pushError(m_context, "Failed to validate against exactly one child schema.");
+            }
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a PatternConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const PatternConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isString()) || !m_target.maybeString()) {
+            return true;
+        }
+
+        std::string pattern(constraint.getPattern<std::string::allocator_type>());
+        auto it = m_regexesCache.find(pattern);
+        if (it == m_regexesCache.end()) {
+            it = m_regexesCache.emplace(pattern, std::regex(pattern)).first;
+        }
+
+        if (!std::regex_search(m_target.asString(), it->second)) {
+            if (m_results) {
+                m_results->pushError(m_context, "Failed to match regex specified by 'pattern' constraint.");
+            }
+
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a PatternConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const constraints::PolyConstraint &constraint) override
+    {
+        return constraint.validate(m_target, m_context, m_results);
+    }
+
+    /**
+     * @brief   Validate a value against a PropertiesConstraint
+     *
+     * Validation of an object against a PropertiesConstraint proceeds in three
+     * stages. The first stage finds all properties in the object that have a
+     * corresponding subschema in the constraint, and validates those properties
+     * recursively.
+     *
+     * Next, the object's properties will be validated against the subschemas
+     * for any 'patternProperties' that match a given property name. A property
+     * is required to validate against the sub-schema for all patterns that it
+     * matches.
+     *
+     * Finally, any properties that have not yet been validated against at least
+     * one subschema will be validated against the 'additionalItems' subschema.
+     * If this subschema is not present, then all properties must have been
+     * validated at least once.
+     *
+     * Non-object values are always considered valid.
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if the constraint is satisfied; \c false otherwise
+     */
+    bool visit(const PropertiesConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isObject()) || !m_target.maybeObject()) {
+            return true;
+        }
+
+        bool validated = true;
+
+        // Track which properties have already been validated
+        std::set<std::string> propertiesMatched;
+
+        // Validate properties against subschemas for matching 'properties'
+        // constraints
+        const typename AdapterType::Object object = m_target.asObject();
+        constraint.applyToProperties(
+                ValidatePropertySubschemas(
+                        object, m_context, true, m_results != nullptr, true, m_strictTypes, m_results,
+                        &propertiesMatched, &validated, m_regexesCache));
+
+        // Exit early if validation failed, and we're not collecting exhaustive
+        // validation results
+        if (!validated && !m_results) {
+            return false;
+        }
+
+        // Validate properties against subschemas for matching patternProperties
+        // constraints
+        constraint.applyToPatternProperties(
+                ValidatePatternPropertySubschemas(
+                        object, m_context, true, false, true, m_strictTypes, m_results, &propertiesMatched,
+                        &validated, m_regexesCache));
+
+        // Validate against additionalProperties subschema for any properties
+        // that have not yet been matched
+        const Subschema *additionalPropertiesSubschema =
+                constraint.getAdditionalPropertiesSubschema();
+        if (!additionalPropertiesSubschema) {
+            if (propertiesMatched.size() != m_target.getObjectSize()) {
+                if (m_results) {
+                    std::string unwanted;
+                    for (const typename AdapterType::ObjectMember m : object) {
+                        if (propertiesMatched.find(m.first) == propertiesMatched.end()) {
+                            unwanted = m.first;
+                            break;
+                        }
+                    }
+                    m_results->pushError(m_context, "Object contains a property "
+                            "that could not be validated using 'properties' "
+                            "or 'additionalProperties' constraints: '" + unwanted + "'.");
+                }
+
+                return false;
+            }
+
+            return validated;
+        }
+
+        for (const typename AdapterType::ObjectMember m : object) {
+            if (propertiesMatched.find(m.first) == propertiesMatched.end()) {
+                // Update context
+                std::vector<std::string> newContext = m_context;
+                newContext.push_back("[" + m.first + "]");
+
+                // Create a validator to validate the property's value
+                ValidationVisitor validator(m.second, newContext, m_strictTypes, m_results, m_regexesCache);
+                if (!validator.validateSchema(*additionalPropertiesSubschema)) {
+                    if (m_results) {
+                        m_results->pushError(m_context, "Failed to validate against additional properties schema");
+                    }
+
+                    validated = false;
+                }
+            }
+        }
+
+        return validated;
+    }
+
+    /**
+     * @brief   Validate a value against a PropertyNamesConstraint
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if validation succeeds; \c false otherwise
+     */
+    bool visit(const PropertyNamesConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isObject()) || !m_target.maybeObject()) {
+            return true;
+        }
+
+        for (const typename AdapterType::ObjectMember m : m_target.asObject()) {
+            adapters::StdStringAdapter stringAdapter(m.first);
+            ValidationVisitor<adapters::StdStringAdapter> validator(stringAdapter, m_context, m_strictTypes, nullptr, m_regexesCache);
+            if (!validator.validateSchema(*constraint.getSubschema())) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @brief   Validate a value against a RequiredConstraint
+     *
+     * A required constraint specifies a list of properties that must be present
+     * in the target.
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  \c true if validation succeeds; \c false otherwise
+     */
+    bool visit(const RequiredConstraint &constraint) override
+    {
+        if ((m_strictTypes && !m_target.isObject()) || !m_target.maybeObject()) {
+            return true;
+        }
+
+        bool validated = true;
+        const typename AdapterType::Object object = m_target.asObject();
+        constraint.applyToRequiredProperties(
+                ValidateProperties(object, m_context, true, m_results != nullptr, m_results, &validated));
+
+        return validated;
+    }
+
+    /**
+     * @brief  Validate a value against a SingularItemsConstraint
+     *
+     * A SingularItemsConstraint represents an 'items' constraint that specifies
+     * a sub-schema against which all items in an array must validate. If the
+     * current value is not an array, validation always succeeds.
+     *
+     * @param  constraint  SingularItemsConstraint to validate against
+     *
+     * @returns  \c true if validation is successful; \c false otherwise
+     */
+    bool visit(const SingularItemsConstraint &constraint) override
+    {
+        // Ignore values that are not arrays
+        if (!m_target.isArray()) {
+            return true;
+        }
+
+        // Schema against which all items must validate
+        const Subschema *itemsSubschema = constraint.getItemsSubschema();
+
+        // Default items sub-schema accepts all values
+        if (!itemsSubschema) {
+            return true;
+        }
+
+        // Track whether validation has failed
+        bool validated = true;
+
+        unsigned int index = 0;
+        for (const AdapterType &item : m_target.getArray()) {
+            // Update context for current array item
+            std::vector<std::string> newContext = m_context;
+            newContext.push_back("[" + std::to_string(index) + "]");
+
+            // Create a validator for the current array item
+            ValidationVisitor<AdapterType> validationVisitor(item, newContext, m_strictTypes, m_results, m_regexesCache);
+
+            // Perform validation
+            if (!validationVisitor.validateSchema(*itemsSubschema)) {
+                if (m_results) {
+                    m_results->pushError(m_context, "Failed to validate item #" + std::to_string(index) + " in array.");
+                    validated = false;
+                } else {
+                    return false;
+                }
+            }
+
+            index++;
+        }
+
+        return validated;
+    }
+
+    /**
+     * @brief   Validate a value against a TypeConstraint
+     *
+     * Checks that the target is one of the valid named types, or matches one
+     * of a set of valid sub-schemas.
+     *
+     * @param   constraint  TypeConstraint to validate against
+     *
+     * @return  \c true if validation is successful; \c false otherwise
+     */
+    bool visit(const TypeConstraint &constraint) override
+    {
+        // Check named types
+        {
+            // ValidateNamedTypes functor assumes target is invalid
+            bool validated = false;
+            constraint.applyToNamedTypes(ValidateNamedTypes(m_target, false, true, m_strictTypes, &validated));
+            if (validated) {
+                return true;
+            }
+        }
+
+        // Check schema-based types
+        {
+            unsigned int numValidated = 0;
+            constraint.applyToSchemaTypes(
+                    ValidateSubschemas(m_target, m_context, false, true, *this, nullptr, &numValidated, nullptr));
+            if (numValidated > 0) {
+                return true;
+            } else if (m_results) {
+                m_results->pushError(m_context, "Value type not permitted by 'type' constraint.");
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @brief   Validate the uniqueItems constraint represented by a
+     *          UniqueItems object.
+     *
+     * A uniqueItems constraint requires that each of the values in an array
+     * are unique. Comparison is performed recursively.
+     *
+     * @param   constraint  Constraint that the target must validate against
+     *
+     * @return  true if validation succeeds, false otherwise
+     */
+    bool visit(const UniqueItemsConstraint &) override
+    {
+        if ((m_strictTypes && !m_target.isArray()) || !m_target.maybeArray()) {
+            return true;
+        }
+
+        // Empty arrays are always valid
+        if (m_target.getArraySize() == 0) {
+            return true;
+        }
+
+        bool validated = true;
+
+        const typename AdapterType::Array targetArray = m_target.asArray();
+        const typename AdapterType::Array::const_iterator end = targetArray.end();
+        const typename AdapterType::Array::const_iterator secondLast = --targetArray.end();
+        unsigned int outerIndex = 0;
+        typename AdapterType::Array::const_iterator outerItr = targetArray.begin();
+        for (; outerItr != secondLast; ++outerItr) {
+            unsigned int innerIndex = outerIndex + 1;
+            typename AdapterType::Array::const_iterator innerItr(outerItr);
+            for (++innerItr; innerItr != end; ++innerItr) {
+                if (outerItr->equalTo(*innerItr, true)) {
+                    if (!m_results) {
+                        return false;
+                    }
+                    m_results->pushError(m_context, "Elements at indexes #" + std::to_string(outerIndex)
+                        + " and #" + std::to_string(innerIndex) + " violate uniqueness constraint.");
+                    validated = false;
+                }
+                ++innerIndex;
+            }
+            ++outerIndex;
+        }
+
+        return validated;
+    }
+
+private:
+
+    /**
+     * @brief  Functor to compare a node with a collection of values
+     */
+    struct ValidateEquality
+    {
+        ValidateEquality(
+                const AdapterType &target,
+                const std::vector<std::string> &context,
+                bool continueOnSuccess,
+                bool continueOnFailure,
+                bool strictTypes,
+                ValidationResults *results,
+                unsigned int *numValidated)
+          : m_target(target),
+            m_context(context),
+            m_continueOnSuccess(continueOnSuccess),
+            m_continueOnFailure(continueOnFailure),
+            m_strictTypes(strictTypes),
+            m_results(results),
+            m_numValidated(numValidated) { }
+
+        template<typename OtherValue>
+        bool operator()(const OtherValue &value) const
+        {
+            if (value.equalTo(m_target, m_strictTypes)) {
+                if (m_numValidated) {
+                    (*m_numValidated)++;
+                }
+
+                return m_continueOnSuccess;
+            }
+
+            if (m_results) {
+                m_results->pushError(m_context, "Target value and comparison value are not equal");
+            }
+
+            return m_continueOnFailure;
+        }
+
+    private:
+        const AdapterType &m_target;
+        const std::vector<std::string> &m_context;
+        bool m_continueOnSuccess;
+        bool m_continueOnFailure;
+        bool m_strictTypes;
+        ValidationResults * const m_results;
+        unsigned int * const m_numValidated;
+    };
+
+    /**
+     * @brief  Functor to validate the presence of a set of properties
+     */
+    struct ValidateProperties
+    {
+        ValidateProperties(
+                const typename AdapterType::Object &object,
+                const std::vector<std::string> &context,
+                bool continueOnSuccess,
+                bool continueOnFailure,
+                ValidationResults *results,
+                bool *validated)
+          : m_object(object),
+            m_context(context),
+            m_continueOnSuccess(continueOnSuccess),
+            m_continueOnFailure(continueOnFailure),
+            m_results(results),
+            m_validated(validated) { }
+
+        template<typename StringType>
+        bool operator()(const StringType &property) const
+        {
+            if (m_object.find(property.c_str()) == m_object.end()) {
+                if (m_validated) {
+                    *m_validated = false;
+                }
+
+                if (m_results) {
+                    m_results->pushError(m_context, "Missing required property '" +
+                            std::string(property.c_str()) + "'.");
+                }
+
+                return m_continueOnFailure;
+            }
+
+            return m_continueOnSuccess;
+        }
+
+    private:
+        const typename AdapterType::Object &m_object;
+        const std::vector<std::string> &m_context;
+        bool m_continueOnSuccess;
+        bool m_continueOnFailure;
+        ValidationResults * const m_results;
+        bool * const m_validated;
+    };
+
+    /**
+     * @brief  Functor to validate property-based dependencies
+     */
+    struct ValidatePropertyDependencies
+    {
+        ValidatePropertyDependencies(
+                const typename AdapterType::Object &object,
+                const std::vector<std::string> &context,
+                ValidationResults *results,
+                bool *validated)
+          : m_object(object),
+            m_context(context),
+            m_results(results),
+            m_validated(validated) { }
+
+        template<typename StringType, typename ContainerType>
+        bool operator()(const StringType &propertyName, const ContainerType &dependencyNames) const
+        {
+            const std::string propertyNameKey(propertyName.c_str());
+            if (m_object.find(propertyNameKey) == m_object.end()) {
+                return true;
+            }
+
+            typedef typename ContainerType::value_type ValueType;
+            for (const ValueType &dependencyName : dependencyNames) {
+                const std::string dependencyNameKey(dependencyName.c_str());
+                if (m_object.find(dependencyNameKey) == m_object.end()) {
+                    if (m_validated) {
+                        *m_validated = false;
+                    }
+                    if (m_results) {
+                        m_results->pushError(m_context, "Missing dependency '" + dependencyNameKey + "'.");
+                    } else {
+                        return false;
+                    }
+                }
+            }
+
+            return true;
+        }
+
+    private:
+        const typename AdapterType::Object &m_object;
+        const std::vector<std::string> &m_context;
+        ValidationResults * const m_results;
+        bool * const m_validated;
+    };
+
+    /**
+     * @brief  Functor to validate against sub-schemas in 'items' constraint
+     */
+    struct ValidateItems
+    {
+        ValidateItems(
+                const typename AdapterType::Array &arr,
+                const std::vector<std::string> &context,
+                bool continueOnSuccess,
+                bool continueOnFailure,
+                bool strictTypes,
+                ValidationResults *results,
+                unsigned int *numValidated,
+                bool *validated,
+                std::unordered_map<std::string, std::regex>& regexesCache)
+          : m_arr(arr),
+            m_context(context),
+            m_continueOnSuccess(continueOnSuccess),
+            m_continueOnFailure(continueOnFailure),
+            m_strictTypes(strictTypes),
+            m_results(results),
+            m_numValidated(numValidated),
+            m_validated(validated),
+            m_regexesCache(regexesCache) { }
+
+        bool operator()(unsigned int index, const Subschema *subschema) const
+        {
+            // Check that there are more elements to validate
+            if (index >= m_arr.size()) {
+                return false;
+            }
+
+            // Update context
+            std::vector<std::string> newContext = m_context;
+            newContext.push_back("[" + std::to_string(index) + "]");
+
+            // Find array item
+            typename AdapterType::Array::const_iterator itr = m_arr.begin();
+            itr.advance(index);
+
+            // Validate current array item
+            ValidationVisitor validator(*itr, newContext, m_strictTypes, m_results, m_regexesCache);
+            if (validator.validateSchema(*subschema)) {
+                if (m_numValidated) {
+                    (*m_numValidated)++;
+                }
+
+                return m_continueOnSuccess;
+            }
+
+            if (m_validated) {
+                *m_validated = false;
+            }
+
+            if (m_results) {
+                m_results->pushError(newContext, "Failed to validate item #" + std::to_string(index) +
+                    " against corresponding item schema.");
+            }
+
+            return m_continueOnFailure;
+        }
+
+    private:
+        const typename AdapterType::Array &m_arr;
+        const std::vector<std::string> &m_context;
+        bool m_continueOnSuccess;
+        bool m_continueOnFailure;
+        bool m_strictTypes;
+        ValidationResults * const m_results;
+        unsigned int * const m_numValidated;
+        bool * const m_validated;
+        std::unordered_map<std::string, std::regex>& m_regexesCache;
+    };
+
+    /**
+     * @brief  Functor to validate value against named JSON types
+     */
+    struct ValidateNamedTypes
+    {
+        ValidateNamedTypes(
+                const AdapterType &target,
+                bool continueOnSuccess,
+                bool continueOnFailure,
+                bool strictTypes,
+                bool *validated)
+          : m_target(target),
+            m_continueOnSuccess(continueOnSuccess),
+            m_continueOnFailure(continueOnFailure),
+            m_strictTypes(strictTypes),
+            m_validated(validated) { }
+
+        bool operator()(constraints::TypeConstraint::JsonType jsonType) const
+        {
+            typedef constraints::TypeConstraint TypeConstraint;
+
+            bool valid = false;
+
+            switch (jsonType) {
+            case TypeConstraint::kAny:
+                valid = true;
+                break;
+            case TypeConstraint::kArray:
+                valid = m_target.isArray();
+                break;
+            case TypeConstraint::kBoolean:
+                valid = m_target.isBool() || (!m_strictTypes && m_target.maybeBool());
+                break;
+            case TypeConstraint::kInteger:
+                valid = m_target.isInteger() || (!m_strictTypes && m_target.maybeInteger());
+                break;
+            case TypeConstraint::kNull:
+                valid = m_target.isNull() || (!m_strictTypes && m_target.maybeNull());
+                break;
+            case TypeConstraint::kNumber:
+                valid = m_target.isNumber() || (!m_strictTypes && m_target.maybeDouble());
+                break;
+            case TypeConstraint::kObject:
+                valid = m_target.isObject();
+                break;
+            case TypeConstraint::kString:
+                valid = m_target.isString();
+                break;
+            default:
+                break;
+            }
+
+            if (valid && m_validated) {
+                *m_validated = true;
+            }
+
+            return (valid && m_continueOnSuccess) || m_continueOnFailure;
+        }
+
+    private:
+        const AdapterType m_target;
+        const bool m_continueOnSuccess;
+        const bool m_continueOnFailure;
+        const bool m_strictTypes;
+        bool * const m_validated;
+    };
+
+    /**
+     * @brief  Functor to validate object properties against sub-schemas
+     *         defined by a 'patternProperties' constraint
+     */
+    struct ValidatePatternPropertySubschemas
+    {
+        ValidatePatternPropertySubschemas(
+                const typename AdapterType::Object &object,
+                const std::vector<std::string> &context,
+                bool continueOnSuccess,
+                bool continueOnFailure,
+                bool continueIfUnmatched,
+                bool strictTypes,
+                ValidationResults *results,
+                std::set<std::string> *propertiesMatched,
+                bool *validated,
+                std::unordered_map<std::string, std::regex>& regexesCache)
+          : m_object(object),
+            m_context(context),
+            m_continueOnSuccess(continueOnSuccess),
+            m_continueOnFailure(continueOnFailure),
+            m_continueIfUnmatched(continueIfUnmatched),
+            m_strictTypes(strictTypes),
+            m_results(results),
+            m_propertiesMatched(propertiesMatched),
+            m_validated(validated),
+            m_regexesCache(regexesCache) { }
+
+        template<typename StringType>
+        bool operator()(const StringType &patternProperty, const Subschema *subschema) const
+        {
+            const std::string patternPropertyStr(patternProperty.c_str());
+
+            // It would be nice to store pre-allocated regex objects in the
+            // PropertiesConstraint. does std::regex currently support
+            // custom allocators? Anyway, this isn't an issue here, because Valijson's
+            // JSON Scheme validator does not yet support custom allocators.
+            const std::regex r(patternPropertyStr);
+
+            bool matchFound = false;
+
+            // Recursively validate all matching properties
+            typedef const typename AdapterType::ObjectMember ObjectMember;
+            for (const ObjectMember m : m_object) {
+                if (std::regex_search(m.first, r)) {
+                    matchFound = true;
+                    if (m_propertiesMatched) {
+                        m_propertiesMatched->insert(m.first);
+                    }
+
+                    // Update context
+                    std::vector<std::string> newContext = m_context;
+                    newContext.push_back("[" + m.first + "]");
+
+                    // Recursively validate property's value
+                    ValidationVisitor validator(m.second, newContext, m_strictTypes, m_results, m_regexesCache);
+                    if (validator.validateSchema(*subschema)) {
+                        continue;
+                    }
+
+                    if (m_results) {
+                        m_results->pushError(m_context, "Failed to validate against schema associated with pattern '" +
+                                patternPropertyStr + "'.");
+                    }
+
+                    if (m_validated) {
+                        *m_validated = false;
+                    }
+
+                    if (!m_continueOnFailure) {
+                        return false;
+                    }
+                }
+            }
+
+            // Allow iteration to terminate if there was not at least one match
+            if (!matchFound && !m_continueIfUnmatched) {
+                return false;
+            }
+
+            return m_continueOnSuccess;
+        }
+
+    private:
+        const typename AdapterType::Object &m_object;
+        const std::vector<std::string> &m_context;
+        const bool m_continueOnSuccess;
+        const bool m_continueOnFailure;
+        const bool m_continueIfUnmatched;
+        const bool m_strictTypes;
+        ValidationResults * const m_results;
+        std::set<std::string> * const m_propertiesMatched;
+        bool * const m_validated;
+        std::unordered_map<std::string, std::regex>& m_regexesCache;
+    };
+
+    /**
+     * @brief  Functor to validate object properties against sub-schemas defined
+     *         by a 'properties' constraint
+     */
+    struct ValidatePropertySubschemas
+    {
+        ValidatePropertySubschemas(
+                const typename AdapterType::Object &object,
+                const std::vector<std::string> &context,
+                bool continueOnSuccess,
+                bool continueOnFailure,
+                bool continueIfUnmatched,
+                bool strictTypes,
+                ValidationResults *results,
+                std::set<std::string> *propertiesMatched,
+                bool *validated,
+                std::unordered_map<std::string, std::regex>& regexesCache)
+          : m_object(object),
+            m_context(context),
+            m_continueOnSuccess(continueOnSuccess),
+            m_continueOnFailure(continueOnFailure),
+            m_continueIfUnmatched(continueIfUnmatched),
+            m_strictTypes(strictTypes),
+            m_results(results),
+            m_propertiesMatched(propertiesMatched),
+            m_validated(validated),
+            m_regexesCache(regexesCache) { }
+
+        template<typename StringType>
+        bool operator()(const StringType &propertyName, const Subschema *subschema) const
+        {
+            const std::string propertyNameKey(propertyName.c_str());
+            const typename AdapterType::Object::const_iterator itr = m_object.find(propertyNameKey);
+            if (itr == m_object.end()) {
+                return m_continueIfUnmatched;
+            }
+
+            if (m_propertiesMatched) {
+                m_propertiesMatched->insert(propertyNameKey);
+            }
+
+            // Update context
+            std::vector<std::string> newContext = m_context;
+            newContext.push_back("[" + propertyNameKey + "]");
+
+            // Recursively validate property's value
+            ValidationVisitor validator(itr->second, newContext, m_strictTypes, m_results, m_regexesCache);
+            if (validator.validateSchema(*subschema)) {
+                return m_continueOnSuccess;
+            }
+
+            if (m_results) {
+                m_results->pushError(m_context, "Failed to validate against schema associated with property name '" +
+                        propertyNameKey + "'.");
+            }
+
+            if (m_validated) {
+                *m_validated = false;
+            }
+
+            return m_continueOnFailure;
+        }
+
+    private:
+        const typename AdapterType::Object &m_object;
+        const std::vector<std::string> &m_context;
+        const bool m_continueOnSuccess;
+        const bool m_continueOnFailure;
+        const bool m_continueIfUnmatched;
+        const bool m_strictTypes;
+        ValidationResults * const m_results;
+        std::set<std::string> * const m_propertiesMatched;
+        bool * const m_validated;
+        std::unordered_map<std::string, std::regex>& m_regexesCache;
+    };
+
+    /**
+     * @brief  Functor to validate schema-based dependencies
+     */
+    struct ValidateSchemaDependencies
+    {
+        ValidateSchemaDependencies(
+                const typename AdapterType::Object &object,
+                const std::vector<std::string> &context,
+                ValidationVisitor &validationVisitor,
+                ValidationResults *results,
+                bool *validated)
+          : m_object(object),
+            m_context(context),
+            m_validationVisitor(validationVisitor),
+            m_results(results),
+            m_validated(validated) { }
+
+        template<typename StringType>
+        bool operator()(const StringType &propertyName, const Subschema *schemaDependency) const
+        {
+            const std::string propertyNameKey(propertyName.c_str());
+            if (m_object.find(propertyNameKey) == m_object.end()) {
+                return true;
+            }
+
+            if (!m_validationVisitor.validateSchema(*schemaDependency)) {
+                if (m_validated) {
+                    *m_validated = false;
+                }
+                if (m_results) {
+                    m_results->pushError(m_context, "Failed to validate against dependent schema.");
+                } else {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+    private:
+        const typename AdapterType::Object &m_object;
+        const std::vector<std::string> &m_context;
+        ValidationVisitor &m_validationVisitor;
+        ValidationResults * const m_results;
+        bool * const m_validated;
+    };
+
+    /**
+     * @brief  Functor that can be used to validate one or more subschemas
+     *
+     * This functor is designed to be applied to collections of subschemas
+     * contained within 'allOf', 'anyOf' and 'oneOf' constraints.
+     *
+     * The return value depends on whether a given schema validates, with the
+     * actual return value for a given case being decided at construction time.
+     * The return value is used by the 'applyToSubschemas' functions in the
+     * AllOfConstraint, AnyOfConstraint and OneOfConstrant classes to decide
+     * whether to terminate early.
+     *
+     * The functor uses output parameters (provided at construction) to update
+     * validation state that may be needed by the caller.
+     */
+    struct ValidateSubschemas
+    {
+        ValidateSubschemas(
+                const AdapterType &adapter,
+                const std::vector<std::string> &context,
+                bool continueOnSuccess,
+                bool continueOnFailure,
+                ValidationVisitor &validationVisitor,
+                ValidationResults *results,
+                unsigned int *numValidated,
+                bool *validated)
+          : m_adapter(adapter),
+            m_context(context),
+            m_continueOnSuccess(continueOnSuccess),
+            m_continueOnFailure(continueOnFailure),
+            m_validationVisitor(validationVisitor),
+            m_results(results),
+            m_numValidated(numValidated),
+            m_validated(validated) { }
+
+        bool operator()(unsigned int index, const Subschema *subschema) const
+        {
+            if (m_validationVisitor.validateSchema(*subschema)) {
+                if (m_numValidated) {
+                    (*m_numValidated)++;
+                }
+
+                return m_continueOnSuccess;
+            }
+
+            if (m_validated) {
+                *m_validated = false;
+            }
+
+            if (m_results) {
+                m_results->pushError(m_context,
+                        "Failed to validate against child schema #" + std::to_string(index) + ".");
+            }
+
+            return m_continueOnFailure;
+        }
+
+    private:
+        const AdapterType &m_adapter;
+        const std::vector<std::string> &m_context;
+        bool m_continueOnSuccess;
+        bool m_continueOnFailure;
+        ValidationVisitor &m_validationVisitor;
+        ValidationResults * const m_results;
+        unsigned int * const m_numValidated;
+        bool * const m_validated;
+    };
+
+    /**
+     * @brief  Callback function that passes a visitor to a constraint.
+     *
+     * @param  constraint  Reference to constraint to be visited
+     * @param  visitor     Reference to visitor to be applied
+     *
+     * @return  true if the visitor returns successfully, false otherwise.
+     */
+    static bool validationCallback(const constraints::Constraint &constraint, ValidationVisitor<AdapterType> &visitor)
+    {
+        return constraint.accept(visitor);
+    }
+
+    /// The JSON value being validated
+    const AdapterType m_target;
+
+    /// Vector of strings describing the current object context
+    const std::vector<std::string> m_context;
+
+    /// Optional pointer to a ValidationResults object to be populated
+    ValidationResults *m_results;
+
+    /// Option to use strict type comparison
+    const bool m_strictTypes;
+
+    /// Cached regex objects for pattern constraint
+    std::unordered_map<std::string, std::regex>& m_regexesCache;
+};
+
+}  // namespace valijson
+
+#ifdef _MSC_VER
+#pragma warning( pop )
+#endif
diff --git a/subprojects/valijson/include/valijson/validator.hpp b/subprojects/valijson/include/valijson/validator.hpp
new file mode 100644
index 000000000..b26f625f2
--- /dev/null
+++ b/subprojects/valijson/include/valijson/validator.hpp
@@ -0,0 +1,77 @@
+#pragma once
+
+#include <valijson/schema.hpp>
+#include <valijson/validation_visitor.hpp>
+
+namespace valijson {
+
+class Schema;
+class ValidationResults;
+
+/**
+ * @brief  Class that provides validation functionality.
+ */
+class Validator
+{
+public:
+    enum TypeCheckingMode
+    {
+        kStrongTypes,
+        kWeakTypes
+    };
+
+    /**
+     * @brief  Construct a Validator that uses strong type checking by default
+     */
+    Validator()
+      : strictTypes(true) { }
+
+    /**
+     * @brief  Construct a Validator using a specific type checking mode
+     *
+     * @param  typeCheckingMode  choice of strong or weak type checking
+     */
+    Validator(TypeCheckingMode typeCheckingMode)
+      : strictTypes(typeCheckingMode == kStrongTypes) { }
+
+    /**
+     * @brief  Validate a JSON document and optionally return the results.
+     *
+     * When a ValidationResults object is provided via the \c results parameter,
+     * validation will be performed against each constraint defined by the
+     * schema, even if validation fails for some or all constraints.
+     *
+     * If a pointer to a ValidationResults instance is not provided, validation
+     * will only continue for as long as the constraints are validated
+     * successfully.
+     *
+     * @param  schema   The schema to validate against
+     * @param  target   A rapidjson::Value to be validated
+     *
+     * @param  results  An optional pointer to a ValidationResults instance that
+     *                  will be used to report validation errors
+     *
+     * @returns  true if validation succeeds, false otherwise
+     */
+    template<typename AdapterType>
+    bool validate(const Subschema &schema, const AdapterType &target,
+            ValidationResults *results)
+    {
+        // Construct a ValidationVisitor to perform validation at the root level
+        ValidationVisitor<AdapterType> v(target,
+                std::vector<std::string>(1, "<root>"), strictTypes, results, regexesCache);
+
+        return v.validateSchema(schema);
+    }
+
+private:
+
+    /// Flag indicating that strict type comparisons should be used
+    const bool strictTypes;
+
+    /// Cached regex objects for pattern constraint. Key - pattern.
+    std::unordered_map<std::string, std::regex> regexesCache;
+
+};
+
+}  // namespace valijson
diff --git a/subprojects/websocketpp/websocketpp/CMakeLists.txt b/subprojects/websocketpp/websocketpp/CMakeLists.txt
new file mode 100644
index 000000000..3ea8cc1c4
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/CMakeLists.txt
@@ -0,0 +1,2 @@
+init_target("websocketpp")
+final_target ()
diff --git a/subprojects/websocketpp/websocketpp/COPYING b/subprojects/websocketpp/websocketpp/COPYING
new file mode 100644
index 000000000..f8cc5ba1b
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/COPYING
@@ -0,0 +1,145 @@
+Main Library:
+
+Copyright (c) 2014, Peter Thorson. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    * Neither the name of the WebSocket++ Project nor the
+      names of its contributors may be used to endorse or promote products
+      derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Bundled Libraries:
+
+****** Base 64 Library (base64/base64.hpp) ******
+base64.hpp is a repackaging of the base64.cpp and base64.h files into a
+single header suitable for use as a header only library. This conversion was
+done by Peter Thorson (webmaster@zaphoyd.com) in 2012. All modifications to
+the code are redistributed under the same license as the original, which is
+listed below.
+
+base64.cpp and base64.h
+
+Copyright (C) 2004-2008 René Nyffenegger
+
+This source code is provided 'as-is', without any express or implied
+warranty. In no event will the author be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this source code must not be misrepresented; you must not
+  claim that you wrote the original source code. If you use this source code
+  in a product, an acknowledgment in the product documentation would be
+  appreciated but is not required.
+
+2. Altered source versions must be plainly marked as such, and must not be
+  misrepresented as being the original source code.
+
+3. This notice may not be removed or altered from any source distribution.
+
+René Nyffenegger rene.nyffenegger@adp-gmbh.ch
+
+****** SHA1 Library (sha1/sha1.hpp) ******
+sha1.hpp is a repackaging of the sha1.cpp and sha1.h files from the shallsha1
+library (http://code.google.com/p/smallsha1/) into a single header suitable for
+use as a header only library. This conversion was done by Peter Thorson
+(webmaster@zaphoyd.com) in 2013. All modifications to the code are redistributed
+under the same license as the original, which is listed below.
+
+ Copyright (c) 2011, Micael Hildenborg
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    * Neither the name of Micael Hildenborg nor the
+      names of its contributors may be used to endorse or promote products
+      derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY Micael Hildenborg ''AS IS'' AND ANY
+ EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL Micael Hildenborg BE LIABLE FOR ANY
+ DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+****** MD5 Library (common/md5.hpp) ******
+md5.hpp is a reformulation of the md5.h and md5.c code from
+http://www.opensource.apple.com/source/cups/cups-59/cups/md5.c to allow it to
+function as a component of a header only library. This conversion was done by
+Peter Thorson (webmaster@zaphoyd.com) in 2012 for the WebSocket++ project. The
+changes are released under the same license as the original (listed below)
+
+Copyright (C) 1999, 2002 Aladdin Enterprises.  All rights reserved.
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+
+L. Peter Deutsch
+ghost@aladdin.com
+
+****** UTF8 Validation logic (utf8_validation.hpp) ******
+utf8_validation.hpp is adapted from code originally written by Bjoern Hoehrmann
+<bjoern@hoehrmann.de>. See http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for
+details.
+
+The original license:
+
+Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/subprojects/websocketpp/websocketpp/base64/base64.hpp b/subprojects/websocketpp/websocketpp/base64/base64.hpp
new file mode 100644
index 000000000..ff1561d1c
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/base64/base64.hpp
@@ -0,0 +1,178 @@
+/*
+    ******
+    base64.hpp is a repackaging of the base64.cpp and base64.h files into a
+    single header suitable for use as a header only library. This conversion was
+    done by Peter Thorson (webmaster@zaphoyd.com) in 2012. All modifications to
+    the code are redistributed under the same license as the original, which is
+    listed below.
+    ******
+
+   base64.cpp and base64.h
+
+   Copyright (C) 2004-2008 René Nyffenegger
+
+   This source code is provided 'as-is', without any express or implied
+   warranty. In no event will the author be held liable for any damages
+   arising from the use of this software.
+
+   Permission is granted to anyone to use this software for any purpose,
+   including commercial applications, and to alter it and redistribute it
+   freely, subject to the following restrictions:
+
+   1. The origin of this source code must not be misrepresented; you must not
+      claim that you wrote the original source code. If you use this source code
+      in a product, an acknowledgment in the product documentation would be
+      appreciated but is not required.
+
+   2. Altered source versions must be plainly marked as such, and must not be
+      misrepresented as being the original source code.
+
+   3. This notice may not be removed or altered from any source distribution.
+
+   René Nyffenegger rene.nyffenegger@adp-gmbh.ch
+
+*/
+
+#ifndef _BASE64_HPP_
+#define _BASE64_HPP_
+
+#include <string>
+
+namespace websocketpp {
+
+static std::string const base64_chars =
+             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+             "abcdefghijklmnopqrstuvwxyz"
+             "0123456789+/";
+
+/// Test whether a character is a valid base64 character
+/**
+ * @param c The character to test
+ * @return true if c is a valid base64 character
+ */
+static inline bool is_base64(unsigned char c) {
+    return (c == 43 || // +
+           (c >= 47 && c <= 57) || // /-9
+           (c >= 65 && c <= 90) || // A-Z
+           (c >= 97 && c <= 122)); // a-z
+}
+
+/// Encode a char buffer into a base64 string
+/**
+ * @param input The input data
+ * @param len The length of input in bytes
+ * @return A base64 encoded string representing input
+ */
+inline std::string base64_encode(unsigned char const * input, size_t len) {
+    std::string ret;
+    int i = 0;
+    int j = 0;
+    unsigned char char_array_3[3];
+    unsigned char char_array_4[4];
+
+    while (len--) {
+        char_array_3[i++] = *(input++);
+        if (i == 3) {
+            char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
+            char_array_4[1] = ((char_array_3[0] & 0x03) << 4) +
+                              ((char_array_3[1] & 0xf0) >> 4);
+            char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) +
+                              ((char_array_3[2] & 0xc0) >> 6);
+            char_array_4[3] = char_array_3[2] & 0x3f;
+
+            for(i = 0; (i <4) ; i++) {
+                ret += base64_chars[char_array_4[i]];
+            }
+            i = 0;
+        }
+    }
+
+    if (i) {
+        for(j = i; j < 3; j++) {
+            char_array_3[j] = '\0';
+        }
+
+        char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
+        char_array_4[1] = ((char_array_3[0] & 0x03) << 4) +
+                          ((char_array_3[1] & 0xf0) >> 4);
+        char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) +
+                          ((char_array_3[2] & 0xc0) >> 6);
+        char_array_4[3] = char_array_3[2] & 0x3f;
+
+        for (j = 0; (j < i + 1); j++) {
+            ret += base64_chars[char_array_4[j]];
+        }
+
+        while((i++ < 3)) {
+            ret += '=';
+        }
+    }
+
+    return ret;
+}
+
+/// Encode a string into a base64 string
+/**
+ * @param input The input data
+ * @return A base64 encoded string representing input
+ */
+inline std::string base64_encode(std::string const & input) {
+    return base64_encode(
+        reinterpret_cast<const unsigned char *>(input.data()),
+        input.size()
+    );
+}
+
+/// Decode a base64 encoded string into a string of raw bytes
+/**
+ * @param input The base64 encoded input data
+ * @return A string representing the decoded raw bytes
+ */
+inline std::string base64_decode(std::string const & input) {
+    size_t in_len = input.size();
+    int i = 0;
+    int j = 0;
+    int in_ = 0;
+    unsigned char char_array_4[4], char_array_3[3];
+    std::string ret;
+
+    while (in_len-- && ( input[in_] != '=') && is_base64(input[in_])) {
+        char_array_4[i++] = input[in_]; in_++;
+        if (i ==4) {
+            for (i = 0; i <4; i++) {
+                char_array_4[i] = static_cast<unsigned char>(base64_chars.find(char_array_4[i]));
+            }
+
+            char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
+            char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
+            char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
+
+            for (i = 0; (i < 3); i++) {
+                ret += char_array_3[i];
+            }
+            i = 0;
+        }
+    }
+
+    if (i) {
+        for (j = i; j <4; j++)
+            char_array_4[j] = 0;
+
+        for (j = 0; j <4; j++)
+            char_array_4[j] = static_cast<unsigned char>(base64_chars.find(char_array_4[j]));
+
+        char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
+        char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
+        char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
+
+        for (j = 0; (j < i - 1); j++) {
+            ret += static_cast<std::string::value_type>(char_array_3[j]);
+        }
+    }
+
+    return ret;
+}
+
+} // namespace websocketpp
+
+#endif // _BASE64_HPP_
diff --git a/subprojects/websocketpp/websocketpp/client.hpp b/subprojects/websocketpp/websocketpp/client.hpp
new file mode 100644
index 000000000..8782d7e4a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/client.hpp
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CLIENT_HPP
+#define WEBSOCKETPP_CLIENT_HPP
+
+#include <websocketpp/roles/client_endpoint.hpp>
+
+#endif //WEBSOCKETPP_CLIENT_HPP
diff --git a/subprojects/websocketpp/websocketpp/close.hpp b/subprojects/websocketpp/websocketpp/close.hpp
new file mode 100644
index 000000000..276498e6e
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/close.hpp
@@ -0,0 +1,353 @@
+
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CLOSE_HPP
+#define WEBSOCKETPP_CLOSE_HPP
+
+/** \file
+ * A package of types and methods for manipulating WebSocket close codes.
+ */
+
+#include <websocketpp/error.hpp>
+#include <websocketpp/common/network.hpp>
+#include <websocketpp/common/stdint.hpp>
+#include <websocketpp/utf8_validator.hpp>
+
+#include <string>
+
+namespace websocketpp {
+/// A package of types and methods for manipulating WebSocket close codes.
+namespace close {
+/// A package of types and methods for manipulating WebSocket close status'
+namespace status {
+    /// The type of a close code value.
+    typedef uint16_t value;
+
+    /// A blank value for internal use.
+    static value const blank = 0;
+
+    /// Close the connection without a WebSocket close handshake.
+    /**
+     * This special value requests that the WebSocket connection be closed
+     * without performing the WebSocket closing handshake. This does not comply
+     * with RFC6455, but should be safe to do if necessary. This could be useful
+     * for clients that need to disconnect quickly and cannot afford the
+     * complete handshake.
+     */
+    static value const omit_handshake = 1;
+
+    /// Close the connection with a forced TCP drop.
+    /**
+     * This special value requests that the WebSocket connection be closed by
+     * forcibly dropping the TCP connection. This will leave the other side of
+     * the connection with a broken connection and some expensive timeouts. this
+     * should not be done except in extreme cases or in cases of malicious
+     * remote endpoints.
+     */
+    static value const force_tcp_drop = 2;
+
+    /// Normal closure, meaning that the purpose for which the connection was
+    /// established has been fulfilled.
+    static value const normal = 1000;
+
+    /// The endpoint was "going away", such as a server going down or a browser
+    /// navigating away from a page.
+    static value const going_away = 1001;
+
+    /// A protocol error occurred.
+    static value const protocol_error = 1002;
+
+    /// The connection was terminated because an endpoint received a type of
+    /// data it cannot accept.
+    /**
+     * (e.g., an endpoint that understands only text data MAY send this if it
+     * receives a binary message).
+     */
+    static value const unsupported_data = 1003;
+
+    /// A dummy value to indicate that no status code was received.
+    /**
+     * This value is illegal on the wire.
+     */
+    static value const no_status = 1005;
+
+    /// A dummy value to indicate that the connection was closed abnormally.
+    /**
+     * In such a case there was no close frame to extract a value from. This
+     * value is illegal on the wire.
+     */
+    static value const abnormal_close = 1006;
+
+    /// An endpoint received message data inconsistent with its type.
+    /**
+     * For example: Invalid UTF8 bytes in a text message.
+     */
+    static value const invalid_payload = 1007;
+
+    /// An endpoint received a message that violated its policy.
+    /**
+     * This is a generic status code that can be returned when there is no other
+     * more suitable status code (e.g., 1003 or 1009) or if there is a need to
+     * hide specific details about the policy.
+     */
+    static value const policy_violation = 1008;
+
+    /// An endpoint received a message too large to process.
+    static value const message_too_big = 1009;
+
+    /// A client expected the server to accept a required extension request
+    /**
+     * The list of extensions that are needed SHOULD appear in the /reason/ part
+     * of the Close frame. Note that this status code is not used by the server,
+     * because it can fail the WebSocket handshake instead.
+     */
+    static value const extension_required = 1010;
+
+    /// An endpoint encountered an unexpected condition that prevented it from
+    /// fulfilling the request.
+    static value const internal_endpoint_error = 1011;
+
+    /// Indicates that the service is restarted. A client may reconnect and if
+    /// if it chooses to do so, should reconnect using a randomized delay of
+    /// 5-30s
+    static value const service_restart = 1012;
+
+    /// Indicates that the service is experiencing overload. A client should
+    /// only connect to a different IP (when there are multiple for the target)
+    /// or reconnect to the same IP upon user action.
+    static value const try_again_later = 1013;
+
+    /// Indicates that the server was acting as a gateway or proxy and received
+    /// an invalid response from the upstream server. This is similar to 502
+    /// HTTP Status Code.
+    static value const bad_gateway = 1014;
+
+    /// An endpoint failed to perform a TLS handshake
+    /**
+     * Designated for use in applications expecting a status code to indicate
+     * that the connection was closed due to a failure to perform a TLS
+     * handshake (e.g., the server certificate can't be verified). This value is
+     * illegal on the wire.
+     */
+    static value const tls_handshake = 1015;
+    
+    /// A generic subprotocol error
+    /**
+     * Indicates that a subprotocol error occurred. Typically this involves
+     * receiving a message that is not formatted as a valid message for the
+     * subprotocol in use.
+     */
+    static value const subprotocol_error = 3000;
+    
+    /// A invalid subprotocol data
+    /**
+     * Indicates that data was received that violated the specification of the
+     * subprotocol in use.
+     */
+    static value const invalid_subprotocol_data = 3001;
+
+    /// First value in range reserved for future protocol use
+    static value const rsv_start = 1016;
+    /// Last value in range reserved for future protocol use
+    static value const rsv_end = 2999;
+
+    /// Test whether a close code is in a reserved range
+    /**
+     * @param [in] code The code to test
+     * @return Whether or not code is reserved
+     */
+    inline bool reserved(value code) {
+        return ((code >= rsv_start && code <= rsv_end) ||
+                code == 1004);
+    }
+
+    /// First value in range that is always invalid on the wire
+    static value const invalid_low = 999;
+    /// Last value in range that is always invalid on the wire
+    static value const invalid_high = 5000;
+
+    /// Test whether a close code is invalid on the wire
+    /**
+     * @param [in] code The code to test
+     * @return Whether or not code is invalid on the wire
+     */
+    inline bool invalid(value code) {
+        return (code <= invalid_low || code >= invalid_high ||
+                code == no_status || code == abnormal_close ||
+                code == tls_handshake);
+    }
+
+    /// Determine if the code represents an unrecoverable error
+    /**
+     * There is a class of errors for which once they are discovered normal
+     * WebSocket functionality can no longer occur. This function determines
+     * if a given code is one of these values. This information is used to
+     * determine if the system has the capability of waiting for a close
+     * acknowledgement or if it should drop the TCP connection immediately
+     * after sending its close frame.
+     *
+     * @param [in] code The value to test.
+     * @return True if the code represents an unrecoverable error
+     */
+    inline bool terminal(value code) {
+        return (code == protocol_error || code == invalid_payload ||
+                code == policy_violation || code == message_too_big ||
+                 code == internal_endpoint_error);
+    }
+    
+    /// Return a human readable interpretation of a WebSocket close code
+    /**
+     * See https://tools.ietf.org/html/rfc6455#section-7.4 for more details.
+     *
+     * @since 0.3.0
+     *
+     * @param [in] code The code to look up.
+     * @return A human readable interpretation of the code.
+     */
+    inline std::string get_string(value code) {
+        switch (code) {
+            case normal:
+                return "Normal close";
+            case going_away:
+                return "Going away";
+            case protocol_error:
+                return "Protocol error";
+            case unsupported_data:
+                return "Unsupported data";
+            case no_status:
+                return "No status set";
+            case abnormal_close:
+                return "Abnormal close";
+            case invalid_payload:
+                return "Invalid payload";
+            case policy_violation:
+                return "Policy violoation";
+            case message_too_big:
+                return "Message too big";
+            case extension_required:
+                return "Extension required";
+            case internal_endpoint_error:
+                return "Internal endpoint error";
+            case service_restart:
+                return "Service restart";
+            case try_again_later:
+                return "Try again later";
+            case bad_gateway:
+                return "Bad gateway";
+            case tls_handshake:
+                return "TLS handshake failure";
+            case subprotocol_error:
+                return "Generic subprotocol error";
+            case invalid_subprotocol_data:
+                return "Invalid subprotocol data";
+            default:
+                return "Unknown";
+        }
+    }
+} // namespace status
+
+/// Type used to convert close statuses between integer and wire representations
+union code_converter {
+    uint16_t i;
+    char c[2];
+};
+
+/// Extract a close code value from a close payload
+/**
+ * If there is no close value (ie string is empty) status::no_status is
+ * returned. If a code couldn't be extracted (usually do to a short or
+ * otherwise mangled payload) status::protocol_error is returned and the ec
+ * value is flagged as an error. Note that this case is different than the case
+ * where protocol error is received over the wire.
+ *
+ * If the value is in an invalid or reserved range ec is set accordingly.
+ *
+ * @param [in] payload Close frame payload value received over the wire.
+ * @param [out] ec Set to indicate what error occurred, if any.
+ * @return The extracted value
+ */
+inline status::value extract_code(std::string const & payload, lib::error_code
+    & ec)
+{
+    ec = lib::error_code();
+
+    if (payload.size() == 0) {
+        return status::no_status;
+    } else if (payload.size() == 1) {
+        ec = make_error_code(error::bad_close_code);
+        return status::protocol_error;
+    }
+
+    code_converter val;
+
+    val.c[0] = payload[0];
+    val.c[1] = payload[1];
+
+    status::value code(ntohs(val.i));
+
+    if (status::invalid(code)) {
+        ec = make_error_code(error::invalid_close_code);
+    }
+
+    if (status::reserved(code)) {
+        ec = make_error_code(error::reserved_close_code);
+    }
+
+    return code;
+}
+
+/// Extract the reason string from a close payload
+/**
+ * The string should be a valid UTF8 message. error::invalid_utf8 will be set if
+ * the function extracts a reason that is not valid UTF8.
+ *
+ * @param [in] payload The payload string to extract a reason from.
+ * @param [out] ec Set to indicate what error occurred, if any.
+ * @return The reason string.
+ */
+inline std::string extract_reason(std::string const & payload, lib::error_code
+    & ec)
+{
+    std::string reason;
+    ec = lib::error_code();
+
+    if (payload.size() > 2) {
+        reason.append(payload.begin()+2,payload.end());
+    }
+
+    if (!websocketpp::utf8_validator::validate(reason)) {
+        ec = make_error_code(error::invalid_utf8);
+    }
+
+    return reason;
+}
+
+} // namespace close
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CLOSE_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/asio.hpp b/subprojects/websocketpp/websocketpp/common/asio.hpp
new file mode 100644
index 000000000..3c8fa13e9
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/asio.hpp
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_ASIO_HPP
+#define WEBSOCKETPP_COMMON_ASIO_HPP
+
+// This file goes to some length to preserve compatibility with versions of 
+// boost older than 1.49 (where the first modern steady_timer timer based on 
+// boost/std chrono was introduced.
+//
+// For the versions older than 1.49, the deadline_timer is used instead. this
+// brings in dependencies on boost date_time and it has a different interface
+// that is normalized by the `lib::asio::is_neg` and `lib::asio::milliseconds`
+// wrappers provided by this file.
+//
+// The primary reason for this continued support is that boost 1.48 is the
+// default and not easily changeable version of boost supplied by the package
+// manager of popular Linux distributions like Ubuntu 12.04 LTS. Once the need
+// for this has passed this should be cleaned up and simplified.
+
+#ifdef ASIO_STANDALONE
+    #include <asio/version.hpp>
+    
+    #if (ASIO_VERSION/100000) == 1 && ((ASIO_VERSION/100)%1000) < 8
+        static_assert(false, "The minimum version of standalone Asio is 1.8.0");
+    #endif
+    
+    #include <asio.hpp>
+    #include <asio/steady_timer.hpp>
+    #include <websocketpp/common/chrono.hpp> 
+#else
+    #include <boost/version.hpp>
+    
+    // See note above about boost <1.49 compatibility. If we are running on 
+    // boost > 1.48 pull in the steady timer and chrono library
+    #if (BOOST_VERSION/100000) == 1 && ((BOOST_VERSION/100)%1000) > 48
+        #include <boost/asio/steady_timer.hpp>
+        #include <websocketpp/common/chrono.hpp>
+    #endif
+    
+    #include <boost/asio.hpp>
+    #include <boost/system/error_code.hpp>
+#endif
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef ASIO_STANDALONE
+    namespace asio {
+        using namespace ::asio;
+        // Here we assume that we will be using std::error_code with standalone
+        // Asio. This is probably a good assumption, but it is possible in rare
+        // cases that local Asio versions would be used.
+        using std::errc;
+        
+        // See note above about boost <1.49 compatibility. Because we require
+        // a standalone Asio version of 1.8+ we are guaranteed to have 
+        // steady_timer available. By convention we require the chrono library
+        // (either boost or std) for use with standalone Asio.
+        template <typename T>
+        bool is_neg(T duration) {
+            return duration.count() < 0;
+        }
+        inline lib::chrono::milliseconds milliseconds(long duration) {
+            return lib::chrono::milliseconds(duration);
+        }
+    } // namespace asio
+    
+#else
+    namespace asio {
+        using namespace boost::asio;
+        
+        // See note above about boost <1.49 compatibility
+        #if (BOOST_VERSION/100000) == 1 && ((BOOST_VERSION/100)%1000) > 48
+            // Using boost::asio >=1.49 so we use chrono and steady_timer
+            template <typename T>
+            bool is_neg(T duration) {
+                return duration.count() < 0;
+            }
+
+            // If boost believes it has std::chrono available it will use it
+            // so we should also use it for things that relate to boost, even
+            // if the library would otherwise use boost::chrono.
+            #if defined(BOOST_ASIO_HAS_STD_CHRONO)
+                inline std::chrono::milliseconds milliseconds(long duration) {
+                    return std::chrono::milliseconds(duration);
+                }
+            #else
+                inline lib::chrono::milliseconds milliseconds(long duration) {
+                    return lib::chrono::milliseconds(duration);
+                }
+            #endif
+        #else
+            // Using boost::asio <1.49 we pretend a deadline timer is a steady
+            // timer and wrap the negative detection and duration conversion
+            // appropriately.
+            typedef boost::asio::deadline_timer steady_timer;
+            
+            template <typename T>
+            bool is_neg(T duration) {
+                return duration.is_negative();
+            }
+            inline boost::posix_time::time_duration milliseconds(long duration) {
+                return boost::posix_time::milliseconds(duration);
+            }
+        #endif
+        
+        using boost::system::error_code;
+        namespace errc = boost::system::errc;
+    } // namespace asio
+#endif
+
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_ASIO_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/asio_ssl.hpp b/subprojects/websocketpp/websocketpp/common/asio_ssl.hpp
new file mode 100644
index 000000000..698928322
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/asio_ssl.hpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_ASIO_SSL_HPP
+#define WEBSOCKETPP_COMMON_ASIO_SSL_HPP
+
+// NOTE: This file must be included before common/asio.hpp
+
+#ifdef ASIO_STANDALONE
+    #include <asio/ssl.hpp>
+#else
+    #include <boost/asio/ssl.hpp>
+#endif
+
+#endif // WEBSOCKETPP_COMMON_ASIO_SSL_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/chrono.hpp b/subprojects/websocketpp/websocketpp/common/chrono.hpp
new file mode 100644
index 000000000..975ee043d
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/chrono.hpp
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_CHRONO_HPP
+#define WEBSOCKETPP_COMMON_CHRONO_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+
+// If we've determined that we're in full C++11 mode and the user hasn't
+// explicitly disabled the use of C++11 functional header, then prefer it to
+// boost.
+#if defined _WEBSOCKETPP_CPP11_INTERNAL_ && !defined _WEBSOCKETPP_NO_CPP11_CHRONO_
+    #ifndef _WEBSOCKETPP_CPP11_CHRONO_
+        #define _WEBSOCKETPP_CPP11_CHRONO_
+    #endif
+#endif
+
+// If we're on Visual Studio 2012 or higher and haven't explicitly disabled
+// the use of C++11 chrono header then prefer it to boost.
+#if defined(_MSC_VER) && _MSC_VER >= 1700 && !defined _WEBSOCKETPP_NO_CPP11_CHRONO_
+    #ifndef _WEBSOCKETPP_CPP11_CHRONO_
+        #define _WEBSOCKETPP_CPP11_CHRONO_
+    #endif
+#endif
+
+#ifdef _WEBSOCKETPP_CPP11_CHRONO_
+    #include <chrono>
+#else
+    #include <boost/chrono.hpp>
+#endif
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef _WEBSOCKETPP_CPP11_CHRONO_
+    namespace chrono = std::chrono;
+#else
+    namespace chrono = boost::chrono;
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_CHRONO_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/connection_hdl.hpp b/subprojects/websocketpp/websocketpp/common/connection_hdl.hpp
new file mode 100644
index 000000000..1044c88e3
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/connection_hdl.hpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_CONNECTION_HDL_HPP
+#define WEBSOCKETPP_COMMON_CONNECTION_HDL_HPP
+
+#include <websocketpp/common/memory.hpp>
+
+namespace websocketpp {
+
+/// A handle to uniquely identify a connection.
+/**
+ * This type uniquely identifies a connection. It is implemented as a weak
+ * pointer to the connection in question. This provides uniqueness across
+ * multiple endpoints and ensures that IDs never conflict or run out.
+ *
+ * It is safe to make copies of this handle, store those copies in containers,
+ * and use them from other threads.
+ *
+ * This handle can be upgraded to a full shared_ptr using
+ * `endpoint::get_con_from_hdl()` from within a handler fired by the connection
+ * that owns the handler.
+ */
+typedef lib::weak_ptr<void> connection_hdl;
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_CONNECTION_HDL_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/cpp11.hpp b/subprojects/websocketpp/websocketpp/common/cpp11.hpp
new file mode 100644
index 000000000..492a3b8ff
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/cpp11.hpp
@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_CPP11_HPP
+#define WEBSOCKETPP_COMMON_CPP11_HPP
+
+/**
+ * This header sets up some constants based on the state of C++11 support
+ */
+
+// Hide clang feature detection from other compilers
+#ifndef __has_feature         // Optional of course.
+  #define __has_feature(x) 0  // Compatibility with non-clang compilers.
+#endif
+#ifndef __has_extension
+  #define __has_extension __has_feature // Compatibility with pre-3.0 compilers.
+#endif
+
+// The code below attempts to use information provided by the build system or
+// user supplied defines to selectively enable C++11 language and library
+// features. In most cases features that are targeted individually may also be
+// selectively disabled via an associated _WEBSOCKETPP_NOXXX_ define.
+
+#if defined(_WEBSOCKETPP_CPP11_STL_) || __cplusplus >= 201103L || defined(_WEBSOCKETPP_CPP11_STRICT_)
+    // This check tests for blanket c++11 coverage. It can be activated in one
+    // of three ways. Either the compiler itself reports that it is a full 
+    // C++11 compiler via the __cplusplus macro or the user/build system
+    // supplies one of the two preprocessor defines below:
+    
+    // This is defined to allow other WebSocket++ common headers to enable
+    // C++11 features when they are detected by this file rather than
+    // duplicating the above logic in every common header.
+    #define _WEBSOCKETPP_CPP11_INTERNAL_
+    
+    // _WEBSOCKETPP_CPP11_STRICT_
+    //
+    // This define reports to WebSocket++ that 100% of the language and library
+    // features of C++11 are available. Using this define on a non-C++11
+    // compiler will result in problems.
+    
+    // _WEBSOCKETPP_CPP11_STL_ 
+    //
+    // This define enables *most* C++11 options that were implemented early on
+    // by compilers. It is typically used for compilers that have many, but not
+    // all C++11 features. It should be safe to use on GCC 4.7-4.8 and perhaps
+    // earlier. 
+    #ifndef _WEBSOCKETPP_NOEXCEPT_TOKEN_
+        #define _WEBSOCKETPP_NOEXCEPT_TOKEN_ noexcept
+    #endif
+    #ifndef _WEBSOCKETPP_CONSTEXPR_TOKEN_
+        #define _WEBSOCKETPP_CONSTEXPR_TOKEN_ constexpr
+    #endif
+    #ifndef _WEBSOCKETPP_INITIALIZER_LISTS_
+        #define _WEBSOCKETPP_INITIALIZER_LISTS_
+    #endif
+    #ifndef _WEBSOCKETPP_NULLPTR_TOKEN_
+        #define _WEBSOCKETPP_NULLPTR_TOKEN_ nullptr
+    #endif
+    #ifndef _WEBSOCKETPP_MOVE_SEMANTICS_
+        #define _WEBSOCKETPP_MOVE_SEMANTICS_
+    #endif
+    #ifndef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+        #define _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+    #endif
+    
+    #ifndef __GNUC__
+        // GCC as of version 4.9 (latest) does not support std::put_time yet.
+        // so ignore it
+        #define _WEBSOCKETPP_PUTTIME_
+    #endif
+#else
+    // In the absence of a blanket define, try to use compiler versions or
+    // feature testing macros to selectively enable what we can.
+
+    // Test for noexcept
+    #ifndef _WEBSOCKETPP_NOEXCEPT_TOKEN_
+        #ifdef _WEBSOCKETPP_NOEXCEPT_
+            // build system says we have noexcept
+            #define _WEBSOCKETPP_NOEXCEPT_TOKEN_ noexcept
+        #else
+            #if __has_feature(cxx_noexcept)
+                // clang feature detect says we have noexcept
+                #define _WEBSOCKETPP_NOEXCEPT_TOKEN_ noexcept
+            #elif defined(_MSC_VER) && _MSC_VER >= 1900
+            	// Visual Studio 2015+ has noexcept
+                #define _WEBSOCKETPP_NOEXCEPT_TOKEN_ noexcept
+            #else
+                // assume we don't have noexcept
+                #define _WEBSOCKETPP_NOEXCEPT_TOKEN_
+            #endif
+        #endif
+    #endif
+
+    // Test for constexpr
+    #ifndef _WEBSOCKETPP_CONSTEXPR_TOKEN_
+        #ifdef _WEBSOCKETPP_CONSTEXPR_
+            // build system says we have constexpr
+            #define _WEBSOCKETPP_CONSTEXPR_TOKEN_ constexpr
+        #else
+            #if __has_feature(cxx_constexpr)
+                // clang feature detect says we have constexpr
+                #define _WEBSOCKETPP_CONSTEXPR_TOKEN_ constexpr
+            #elif defined(_MSC_VER) && _MSC_VER >= 1900
+            	// Visual Studio 2015+ has constexpr
+                #define _WEBSOCKETPP_CONSTEXPR_TOKEN_ constexpr
+            #else
+                // assume we don't have constexpr
+                #define _WEBSOCKETPP_CONSTEXPR_TOKEN_
+            #endif
+        #endif
+    #endif
+
+    // Enable initializer lists on clang when available.
+    #if __has_feature(cxx_generalized_initializers) && !defined(_WEBSOCKETPP_INITIALIZER_LISTS_)
+        #define _WEBSOCKETPP_INITIALIZER_LISTS_
+    #endif
+    
+    // Test for nullptr
+    #ifndef _WEBSOCKETPP_NULLPTR_TOKEN_
+        #ifdef _WEBSOCKETPP_NULLPTR_
+            // build system says we have nullptr
+            #define _WEBSOCKETPP_NULLPTR_TOKEN_ nullptr
+        #else
+            #if __has_feature(cxx_nullptr)
+                // clang feature detect says we have nullptr
+                #define _WEBSOCKETPP_NULLPTR_TOKEN_ nullptr
+            #elif defined(_MSC_VER) &&_MSC_VER >= 1600
+                // Visual Studio version that has nullptr
+                #define _WEBSOCKETPP_NULLPTR_TOKEN_ nullptr
+            #else
+                // assume we don't have nullptr
+                #define _WEBSOCKETPP_NULLPTR_TOKEN_ 0
+            #endif
+        #endif
+    #endif
+#endif
+
+#endif // WEBSOCKETPP_COMMON_CPP11_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/functional.hpp b/subprojects/websocketpp/websocketpp/common/functional.hpp
new file mode 100644
index 000000000..d332dd15e
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/functional.hpp
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_FUNCTIONAL_HPP
+#define WEBSOCKETPP_COMMON_FUNCTIONAL_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+
+// If we've determined that we're in full C++11 mode and the user hasn't
+// explicitly disabled the use of C++11 functional header, then prefer it to
+// boost.
+#if defined _WEBSOCKETPP_CPP11_INTERNAL_ && !defined _WEBSOCKETPP_NO_CPP11_FUNCTIONAL_
+    #ifndef _WEBSOCKETPP_CPP11_FUNCTIONAL_
+        #define _WEBSOCKETPP_CPP11_FUNCTIONAL_
+    #endif
+#endif
+
+// If we're on Visual Studio 2010 or higher and haven't explicitly disabled
+// the use of C++11 functional header then prefer it to boost.
+#if defined(_MSC_VER) && _MSC_VER >= 1600 && !defined _WEBSOCKETPP_NO_CPP11_FUNCTIONAL_
+    #ifndef _WEBSOCKETPP_CPP11_FUNCTIONAL_
+        #define _WEBSOCKETPP_CPP11_FUNCTIONAL_
+    #endif
+#endif
+
+
+
+#ifdef _WEBSOCKETPP_CPP11_FUNCTIONAL_
+    #include <functional>
+#else
+    #include <boost/bind.hpp>
+    #include <boost/function.hpp>
+    #include <boost/ref.hpp>
+#endif
+
+
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef _WEBSOCKETPP_CPP11_FUNCTIONAL_
+    using std::function;
+    using std::bind;
+    using std::ref;
+    namespace placeholders = std::placeholders;
+
+    // There are some cases where a C++11 compiler balks at using std::ref
+    // but a C++03 compiler using boost function requires boost::ref. As such
+    // lib::ref is not useful in these cases. Instead this macro allows the use
+    // of boost::ref in the case of a boost compile or no reference wrapper at
+    // all in the case of a C++11 compile
+    #define _WEBSOCKETPP_REF(x) x
+
+    template <typename T>
+    void clear_function(T & x) {
+        x = nullptr;
+    }
+#else
+    using boost::function;
+    using boost::bind;
+    using boost::ref;
+    namespace placeholders {
+        /// \todo this feels hacky, is there a better way?
+        using ::_1;
+        using ::_2;
+        using ::_3;
+    }
+
+    // See above definition for more details on what this is and why it exists
+    #define _WEBSOCKETPP_REF(x) boost::ref(x)
+
+    template <typename T>
+    void clear_function(T & x) {
+        x.clear();
+    }
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_FUNCTIONAL_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/md5.hpp b/subprojects/websocketpp/websocketpp/common/md5.hpp
new file mode 100644
index 000000000..279725f45
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/md5.hpp
@@ -0,0 +1,448 @@
+/*
+  md5.hpp is a reformulation of the md5.h and md5.c code from
+  http://www.opensource.apple.com/source/cups/cups-59/cups/md5.c to allow it to
+  function as a component of a header only library. This conversion was done by
+  Peter Thorson (webmaster@zaphoyd.com) in 2012 for the WebSocket++ project. The
+  changes are released under the same license as the original (listed below)
+*/
+/*
+  Copyright (C) 1999, 2002 Aladdin Enterprises.  All rights reserved.
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+
+  L. Peter Deutsch
+  ghost@aladdin.com
+
+ */
+/* $Id: md5.h,v 1.4 2002/04/13 19:20:28 lpd Exp $ */
+/*
+  Independent implementation of MD5 (RFC 1321).
+
+  This code implements the MD5 Algorithm defined in RFC 1321, whose
+  text is available at
+    http://www.ietf.org/rfc/rfc1321.txt
+  The code is derived from the text of the RFC, including the test suite
+  (section A.5) but excluding the rest of Appendix A.  It does not include
+  any code or documentation that is identified in the RFC as being
+  copyrighted.
+
+  The original and principal author of md5.h is L. Peter Deutsch
+  <ghost@aladdin.com>.  Other authors are noted in the change history
+  that follows (in reverse chronological order):
+
+  2002-04-13 lpd Removed support for non-ANSI compilers; removed
+    references to Ghostscript; clarified derivation from RFC 1321;
+    now handles byte order either statically or dynamically.
+  1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
+  1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5);
+    added conditionalization for C++ compilation from Martin
+    Purschke <purschke@bnl.gov>.
+  1999-05-03 lpd Original version.
+ */
+
+#ifndef WEBSOCKETPP_COMMON_MD5_HPP
+#define WEBSOCKETPP_COMMON_MD5_HPP
+
+/*
+ * This package supports both compile-time and run-time determination of CPU
+ * byte order.  If ARCH_IS_BIG_ENDIAN is defined as 0, the code will be
+ * compiled to run only on little-endian CPUs; if ARCH_IS_BIG_ENDIAN is
+ * defined as non-zero, the code will be compiled to run only on big-endian
+ * CPUs; if ARCH_IS_BIG_ENDIAN is not defined, the code will be compiled to
+ * run on either big- or little-endian CPUs, but will run slightly less
+ * efficiently on either one than if ARCH_IS_BIG_ENDIAN is defined.
+ */
+
+#include <stddef.h>
+#include <string>
+#include <cstring>
+
+namespace websocketpp {
+/// Provides MD5 hashing functionality
+namespace md5 {
+
+typedef unsigned char md5_byte_t; /* 8-bit byte */
+typedef unsigned int md5_word_t; /* 32-bit word */
+
+/* Define the state of the MD5 Algorithm. */
+typedef struct md5_state_s {
+    md5_word_t count[2];    /* message length in bits, lsw first */
+    md5_word_t abcd[4];     /* digest buffer */
+    md5_byte_t buf[64];     /* accumulate block */
+} md5_state_t;
+
+/* Initialize the algorithm. */
+inline void md5_init(md5_state_t *pms);
+
+/* Append a string to the message. */
+inline void md5_append(md5_state_t *pms, md5_byte_t const * data, size_t nbytes);
+
+/* Finish the message and return the digest. */
+inline void md5_finish(md5_state_t *pms, md5_byte_t digest[16]);
+
+#undef ZSW_MD5_BYTE_ORDER   /* 1 = big-endian, -1 = little-endian, 0 = unknown */
+#ifdef ARCH_IS_BIG_ENDIAN
+#  define ZSW_MD5_BYTE_ORDER (ARCH_IS_BIG_ENDIAN ? 1 : -1)
+#else
+#  define ZSW_MD5_BYTE_ORDER 0
+#endif
+
+#define ZSW_MD5_T_MASK ((md5_word_t)~0)
+#define ZSW_MD5_T1 /* 0xd76aa478 */ (ZSW_MD5_T_MASK ^ 0x28955b87)
+#define ZSW_MD5_T2 /* 0xe8c7b756 */ (ZSW_MD5_T_MASK ^ 0x173848a9)
+#define ZSW_MD5_T3    0x242070db
+#define ZSW_MD5_T4 /* 0xc1bdceee */ (ZSW_MD5_T_MASK ^ 0x3e423111)
+#define ZSW_MD5_T5 /* 0xf57c0faf */ (ZSW_MD5_T_MASK ^ 0x0a83f050)
+#define ZSW_MD5_T6    0x4787c62a
+#define ZSW_MD5_T7 /* 0xa8304613 */ (ZSW_MD5_T_MASK ^ 0x57cfb9ec)
+#define ZSW_MD5_T8 /* 0xfd469501 */ (ZSW_MD5_T_MASK ^ 0x02b96afe)
+#define ZSW_MD5_T9    0x698098d8
+#define ZSW_MD5_T10 /* 0x8b44f7af */ (ZSW_MD5_T_MASK ^ 0x74bb0850)
+#define ZSW_MD5_T11 /* 0xffff5bb1 */ (ZSW_MD5_T_MASK ^ 0x0000a44e)
+#define ZSW_MD5_T12 /* 0x895cd7be */ (ZSW_MD5_T_MASK ^ 0x76a32841)
+#define ZSW_MD5_T13    0x6b901122
+#define ZSW_MD5_T14 /* 0xfd987193 */ (ZSW_MD5_T_MASK ^ 0x02678e6c)
+#define ZSW_MD5_T15 /* 0xa679438e */ (ZSW_MD5_T_MASK ^ 0x5986bc71)
+#define ZSW_MD5_T16    0x49b40821
+#define ZSW_MD5_T17 /* 0xf61e2562 */ (ZSW_MD5_T_MASK ^ 0x09e1da9d)
+#define ZSW_MD5_T18 /* 0xc040b340 */ (ZSW_MD5_T_MASK ^ 0x3fbf4cbf)
+#define ZSW_MD5_T19    0x265e5a51
+#define ZSW_MD5_T20 /* 0xe9b6c7aa */ (ZSW_MD5_T_MASK ^ 0x16493855)
+#define ZSW_MD5_T21 /* 0xd62f105d */ (ZSW_MD5_T_MASK ^ 0x29d0efa2)
+#define ZSW_MD5_T22    0x02441453
+#define ZSW_MD5_T23 /* 0xd8a1e681 */ (ZSW_MD5_T_MASK ^ 0x275e197e)
+#define ZSW_MD5_T24 /* 0xe7d3fbc8 */ (ZSW_MD5_T_MASK ^ 0x182c0437)
+#define ZSW_MD5_T25    0x21e1cde6
+#define ZSW_MD5_T26 /* 0xc33707d6 */ (ZSW_MD5_T_MASK ^ 0x3cc8f829)
+#define ZSW_MD5_T27 /* 0xf4d50d87 */ (ZSW_MD5_T_MASK ^ 0x0b2af278)
+#define ZSW_MD5_T28    0x455a14ed
+#define ZSW_MD5_T29 /* 0xa9e3e905 */ (ZSW_MD5_T_MASK ^ 0x561c16fa)
+#define ZSW_MD5_T30 /* 0xfcefa3f8 */ (ZSW_MD5_T_MASK ^ 0x03105c07)
+#define ZSW_MD5_T31    0x676f02d9
+#define ZSW_MD5_T32 /* 0x8d2a4c8a */ (ZSW_MD5_T_MASK ^ 0x72d5b375)
+#define ZSW_MD5_T33 /* 0xfffa3942 */ (ZSW_MD5_T_MASK ^ 0x0005c6bd)
+#define ZSW_MD5_T34 /* 0x8771f681 */ (ZSW_MD5_T_MASK ^ 0x788e097e)
+#define ZSW_MD5_T35    0x6d9d6122
+#define ZSW_MD5_T36 /* 0xfde5380c */ (ZSW_MD5_T_MASK ^ 0x021ac7f3)
+#define ZSW_MD5_T37 /* 0xa4beea44 */ (ZSW_MD5_T_MASK ^ 0x5b4115bb)
+#define ZSW_MD5_T38    0x4bdecfa9
+#define ZSW_MD5_T39 /* 0xf6bb4b60 */ (ZSW_MD5_T_MASK ^ 0x0944b49f)
+#define ZSW_MD5_T40 /* 0xbebfbc70 */ (ZSW_MD5_T_MASK ^ 0x4140438f)
+#define ZSW_MD5_T41    0x289b7ec6
+#define ZSW_MD5_T42 /* 0xeaa127fa */ (ZSW_MD5_T_MASK ^ 0x155ed805)
+#define ZSW_MD5_T43 /* 0xd4ef3085 */ (ZSW_MD5_T_MASK ^ 0x2b10cf7a)
+#define ZSW_MD5_T44    0x04881d05
+#define ZSW_MD5_T45 /* 0xd9d4d039 */ (ZSW_MD5_T_MASK ^ 0x262b2fc6)
+#define ZSW_MD5_T46 /* 0xe6db99e5 */ (ZSW_MD5_T_MASK ^ 0x1924661a)
+#define ZSW_MD5_T47    0x1fa27cf8
+#define ZSW_MD5_T48 /* 0xc4ac5665 */ (ZSW_MD5_T_MASK ^ 0x3b53a99a)
+#define ZSW_MD5_T49 /* 0xf4292244 */ (ZSW_MD5_T_MASK ^ 0x0bd6ddbb)
+#define ZSW_MD5_T50    0x432aff97
+#define ZSW_MD5_T51 /* 0xab9423a7 */ (ZSW_MD5_T_MASK ^ 0x546bdc58)
+#define ZSW_MD5_T52 /* 0xfc93a039 */ (ZSW_MD5_T_MASK ^ 0x036c5fc6)
+#define ZSW_MD5_T53    0x655b59c3
+#define ZSW_MD5_T54 /* 0x8f0ccc92 */ (ZSW_MD5_T_MASK ^ 0x70f3336d)
+#define ZSW_MD5_T55 /* 0xffeff47d */ (ZSW_MD5_T_MASK ^ 0x00100b82)
+#define ZSW_MD5_T56 /* 0x85845dd1 */ (ZSW_MD5_T_MASK ^ 0x7a7ba22e)
+#define ZSW_MD5_T57    0x6fa87e4f
+#define ZSW_MD5_T58 /* 0xfe2ce6e0 */ (ZSW_MD5_T_MASK ^ 0x01d3191f)
+#define ZSW_MD5_T59 /* 0xa3014314 */ (ZSW_MD5_T_MASK ^ 0x5cfebceb)
+#define ZSW_MD5_T60    0x4e0811a1
+#define ZSW_MD5_T61 /* 0xf7537e82 */ (ZSW_MD5_T_MASK ^ 0x08ac817d)
+#define ZSW_MD5_T62 /* 0xbd3af235 */ (ZSW_MD5_T_MASK ^ 0x42c50dca)
+#define ZSW_MD5_T63    0x2ad7d2bb
+#define ZSW_MD5_T64 /* 0xeb86d391 */ (ZSW_MD5_T_MASK ^ 0x14792c6e)
+
+static void md5_process(md5_state_t *pms, md5_byte_t const * data /*[64]*/) {
+    md5_word_t
+    a = pms->abcd[0], b = pms->abcd[1],
+    c = pms->abcd[2], d = pms->abcd[3];
+    md5_word_t t;
+#if ZSW_MD5_BYTE_ORDER > 0
+    /* Define storage only for big-endian CPUs. */
+    md5_word_t X[16];
+#else
+    /* Define storage for little-endian or both types of CPUs. */
+    md5_word_t xbuf[16];
+    md5_word_t const * X;
+#endif
+
+    {
+#if ZSW_MD5_BYTE_ORDER == 0
+    /*
+     * Determine dynamically whether this is a big-endian or
+     * little-endian machine, since we can use a more efficient
+     * algorithm on the latter.
+     */
+    static int const w = 1;
+
+    if (*((md5_byte_t const *)&w)) /* dynamic little-endian */
+#endif
+#if ZSW_MD5_BYTE_ORDER <= 0     /* little-endian */
+    {
+        /*
+         * On little-endian machines, we can process properly aligned
+         * data without copying it.
+         */
+        if (!((data - (md5_byte_t const *)0) & 3)) {
+        /* data are properly aligned */
+        X = (md5_word_t const *)data;
+        } else {
+        /* not aligned */
+        std::memcpy(xbuf, data, 64);
+        X = xbuf;
+        }
+    }
+#endif
+#if ZSW_MD5_BYTE_ORDER == 0
+    else            /* dynamic big-endian */
+#endif
+#if ZSW_MD5_BYTE_ORDER >= 0     /* big-endian */
+    {
+        /*
+         * On big-endian machines, we must arrange the bytes in the
+         * right order.
+         */
+        const md5_byte_t *xp = data;
+        int i;
+
+#  if ZSW_MD5_BYTE_ORDER == 0
+        X = xbuf;       /* (dynamic only) */
+#  else
+#    define xbuf X      /* (static only) */
+#  endif
+        for (i = 0; i < 16; ++i, xp += 4)
+        xbuf[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
+    }
+#endif
+    }
+
+#define ZSW_MD5_ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
+
+    /* Round 1. */
+    /* Let [abcd k s i] denote the operation
+       a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
+#define ZSW_MD5_F(x, y, z) (((x) & (y)) | (~(x) & (z)))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + ZSW_MD5_F(b,c,d) + X[k] + Ti;\
+  a = ZSW_MD5_ROTATE_LEFT(t, s) + b
+    /* Do the following 16 operations. */
+    SET(a, b, c, d,  0,  7,  ZSW_MD5_T1);
+    SET(d, a, b, c,  1, 12,  ZSW_MD5_T2);
+    SET(c, d, a, b,  2, 17,  ZSW_MD5_T3);
+    SET(b, c, d, a,  3, 22,  ZSW_MD5_T4);
+    SET(a, b, c, d,  4,  7,  ZSW_MD5_T5);
+    SET(d, a, b, c,  5, 12,  ZSW_MD5_T6);
+    SET(c, d, a, b,  6, 17,  ZSW_MD5_T7);
+    SET(b, c, d, a,  7, 22,  ZSW_MD5_T8);
+    SET(a, b, c, d,  8,  7,  ZSW_MD5_T9);
+    SET(d, a, b, c,  9, 12, ZSW_MD5_T10);
+    SET(c, d, a, b, 10, 17, ZSW_MD5_T11);
+    SET(b, c, d, a, 11, 22, ZSW_MD5_T12);
+    SET(a, b, c, d, 12,  7, ZSW_MD5_T13);
+    SET(d, a, b, c, 13, 12, ZSW_MD5_T14);
+    SET(c, d, a, b, 14, 17, ZSW_MD5_T15);
+    SET(b, c, d, a, 15, 22, ZSW_MD5_T16);
+#undef SET
+
+     /* Round 2. */
+     /* Let [abcd k s i] denote the operation
+          a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
+#define ZSW_MD5_G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + ZSW_MD5_G(b,c,d) + X[k] + Ti;\
+  a = ZSW_MD5_ROTATE_LEFT(t, s) + b
+     /* Do the following 16 operations. */
+    SET(a, b, c, d,  1,  5, ZSW_MD5_T17);
+    SET(d, a, b, c,  6,  9, ZSW_MD5_T18);
+    SET(c, d, a, b, 11, 14, ZSW_MD5_T19);
+    SET(b, c, d, a,  0, 20, ZSW_MD5_T20);
+    SET(a, b, c, d,  5,  5, ZSW_MD5_T21);
+    SET(d, a, b, c, 10,  9, ZSW_MD5_T22);
+    SET(c, d, a, b, 15, 14, ZSW_MD5_T23);
+    SET(b, c, d, a,  4, 20, ZSW_MD5_T24);
+    SET(a, b, c, d,  9,  5, ZSW_MD5_T25);
+    SET(d, a, b, c, 14,  9, ZSW_MD5_T26);
+    SET(c, d, a, b,  3, 14, ZSW_MD5_T27);
+    SET(b, c, d, a,  8, 20, ZSW_MD5_T28);
+    SET(a, b, c, d, 13,  5, ZSW_MD5_T29);
+    SET(d, a, b, c,  2,  9, ZSW_MD5_T30);
+    SET(c, d, a, b,  7, 14, ZSW_MD5_T31);
+    SET(b, c, d, a, 12, 20, ZSW_MD5_T32);
+#undef SET
+
+     /* Round 3. */
+     /* Let [abcd k s t] denote the operation
+          a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
+#define ZSW_MD5_H(x, y, z) ((x) ^ (y) ^ (z))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + ZSW_MD5_H(b,c,d) + X[k] + Ti;\
+  a = ZSW_MD5_ROTATE_LEFT(t, s) + b
+     /* Do the following 16 operations. */
+    SET(a, b, c, d,  5,  4, ZSW_MD5_T33);
+    SET(d, a, b, c,  8, 11, ZSW_MD5_T34);
+    SET(c, d, a, b, 11, 16, ZSW_MD5_T35);
+    SET(b, c, d, a, 14, 23, ZSW_MD5_T36);
+    SET(a, b, c, d,  1,  4, ZSW_MD5_T37);
+    SET(d, a, b, c,  4, 11, ZSW_MD5_T38);
+    SET(c, d, a, b,  7, 16, ZSW_MD5_T39);
+    SET(b, c, d, a, 10, 23, ZSW_MD5_T40);
+    SET(a, b, c, d, 13,  4, ZSW_MD5_T41);
+    SET(d, a, b, c,  0, 11, ZSW_MD5_T42);
+    SET(c, d, a, b,  3, 16, ZSW_MD5_T43);
+    SET(b, c, d, a,  6, 23, ZSW_MD5_T44);
+    SET(a, b, c, d,  9,  4, ZSW_MD5_T45);
+    SET(d, a, b, c, 12, 11, ZSW_MD5_T46);
+    SET(c, d, a, b, 15, 16, ZSW_MD5_T47);
+    SET(b, c, d, a,  2, 23, ZSW_MD5_T48);
+#undef SET
+
+     /* Round 4. */
+     /* Let [abcd k s t] denote the operation
+          a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
+#define ZSW_MD5_I(x, y, z) ((y) ^ ((x) | ~(z)))
+#define SET(a, b, c, d, k, s, Ti)\
+  t = a + ZSW_MD5_I(b,c,d) + X[k] + Ti;\
+  a = ZSW_MD5_ROTATE_LEFT(t, s) + b
+     /* Do the following 16 operations. */
+    SET(a, b, c, d,  0,  6, ZSW_MD5_T49);
+    SET(d, a, b, c,  7, 10, ZSW_MD5_T50);
+    SET(c, d, a, b, 14, 15, ZSW_MD5_T51);
+    SET(b, c, d, a,  5, 21, ZSW_MD5_T52);
+    SET(a, b, c, d, 12,  6, ZSW_MD5_T53);
+    SET(d, a, b, c,  3, 10, ZSW_MD5_T54);
+    SET(c, d, a, b, 10, 15, ZSW_MD5_T55);
+    SET(b, c, d, a,  1, 21, ZSW_MD5_T56);
+    SET(a, b, c, d,  8,  6, ZSW_MD5_T57);
+    SET(d, a, b, c, 15, 10, ZSW_MD5_T58);
+    SET(c, d, a, b,  6, 15, ZSW_MD5_T59);
+    SET(b, c, d, a, 13, 21, ZSW_MD5_T60);
+    SET(a, b, c, d,  4,  6, ZSW_MD5_T61);
+    SET(d, a, b, c, 11, 10, ZSW_MD5_T62);
+    SET(c, d, a, b,  2, 15, ZSW_MD5_T63);
+    SET(b, c, d, a,  9, 21, ZSW_MD5_T64);
+#undef SET
+
+     /* Then perform the following additions. (That is increment each
+        of the four registers by the value it had before this block
+        was started.) */
+    pms->abcd[0] += a;
+    pms->abcd[1] += b;
+    pms->abcd[2] += c;
+    pms->abcd[3] += d;
+}
+
+void md5_init(md5_state_t *pms) {
+    pms->count[0] = pms->count[1] = 0;
+    pms->abcd[0] = 0x67452301;
+    pms->abcd[1] = /*0xefcdab89*/ ZSW_MD5_T_MASK ^ 0x10325476;
+    pms->abcd[2] = /*0x98badcfe*/ ZSW_MD5_T_MASK ^ 0x67452301;
+    pms->abcd[3] = 0x10325476;
+}
+
+void md5_append(md5_state_t *pms, md5_byte_t const * data, size_t nbytes) {
+    md5_byte_t const * p = data;
+    size_t left = nbytes;
+    int offset = (pms->count[0] >> 3) & 63;
+    md5_word_t nbits = (md5_word_t)(nbytes << 3);
+
+    if (nbytes <= 0)
+    return;
+
+    /* Update the message length. */
+    pms->count[1] += nbytes >> 29;
+    pms->count[0] += nbits;
+    if (pms->count[0] < nbits)
+    pms->count[1]++;
+
+    /* Process an initial partial block. */
+    if (offset) {
+    int copy = (offset + nbytes > 64 ? 64 - offset : static_cast<int>(nbytes));
+
+    std::memcpy(pms->buf + offset, p, copy);
+    if (offset + copy < 64)
+        return;
+    p += copy;
+    left -= copy;
+    md5_process(pms, pms->buf);
+    }
+
+    /* Process full blocks. */
+    for (; left >= 64; p += 64, left -= 64)
+    md5_process(pms, p);
+
+    /* Process a final partial block. */
+    if (left)
+    std::memcpy(pms->buf, p, left);
+}
+
+void md5_finish(md5_state_t *pms, md5_byte_t digest[16]) {
+    static md5_byte_t const pad[64] = {
+    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+    };
+    md5_byte_t data[8];
+    int i;
+
+    /* Save the length before padding. */
+    for (i = 0; i < 8; ++i)
+    data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
+    /* Pad to 56 bytes mod 64. */
+    md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
+    /* Append the length. */
+    md5_append(pms, data, 8);
+    for (i = 0; i < 16; ++i)
+    digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
+}
+
+// some convenience c++ functions
+inline std::string md5_hash_string(std::string const & s) {
+    char digest[16];
+
+    md5_state_t state;
+
+    md5_init(&state);
+    md5_append(&state, (md5_byte_t const *)s.c_str(), s.size());
+    md5_finish(&state, (md5_byte_t *)digest);
+
+    std::string ret;
+    ret.resize(16);
+    std::copy(digest,digest+16,ret.begin());
+
+    return ret;
+}
+
+const char hexval[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+
+inline std::string md5_hash_hex(std::string const & input) {
+    std::string hash = md5_hash_string(input);
+    std::string hex;
+
+    for (size_t i = 0; i < hash.size(); i++) {
+        hex.push_back(hexval[((hash[i] >> 4) & 0xF)]);
+        hex.push_back(hexval[(hash[i]) & 0x0F]);
+    }
+
+    return hex;
+}
+
+} // md5
+} // websocketpp
+
+#endif // WEBSOCKETPP_COMMON_MD5_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/memory.hpp b/subprojects/websocketpp/websocketpp/common/memory.hpp
new file mode 100644
index 000000000..42048e337
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/memory.hpp
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_MEMORY_HPP
+#define WEBSOCKETPP_COMMON_MEMORY_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+
+// If we've determined that we're in full C++11 mode and the user hasn't
+// explicitly disabled the use of C++11 memory header, then prefer it to
+// boost.
+#if defined _WEBSOCKETPP_CPP11_INTERNAL_ && !defined _WEBSOCKETPP_NO_CPP11_MEMORY_
+    #ifndef _WEBSOCKETPP_CPP11_MEMORY_
+        #define _WEBSOCKETPP_CPP11_MEMORY_
+    #endif
+#endif
+
+// If we're on Visual Studio 2010 or higher and haven't explicitly disabled
+// the use of C++11 functional header then prefer it to boost.
+#if defined(_MSC_VER) && _MSC_VER >= 1600 && !defined _WEBSOCKETPP_NO_CPP11_MEMORY_
+    #ifndef _WEBSOCKETPP_CPP11_MEMORY_
+        #define _WEBSOCKETPP_CPP11_MEMORY_
+    #endif
+#endif
+
+
+
+#ifdef _WEBSOCKETPP_CPP11_MEMORY_
+    #include <memory>
+#else
+    #include <boost/shared_ptr.hpp>
+	#include <boost/make_shared.hpp>
+    #include <boost/scoped_array.hpp>
+    #include <boost/enable_shared_from_this.hpp>
+    #include <boost/pointer_cast.hpp>
+#endif
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef _WEBSOCKETPP_CPP11_MEMORY_
+    using std::shared_ptr;
+    using std::weak_ptr;
+    using std::enable_shared_from_this;
+    using std::static_pointer_cast;
+    using std::make_shared;
+    using std::unique_ptr;
+
+    typedef std::unique_ptr<unsigned char[]> unique_ptr_uchar_array;
+#else
+    using boost::shared_ptr;
+    using boost::weak_ptr;
+    using std::auto_ptr;
+    using boost::enable_shared_from_this;
+    using boost::static_pointer_cast;
+    using boost::make_shared;
+
+    typedef boost::scoped_array<unsigned char> unique_ptr_uchar_array;
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_MEMORY_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/network.hpp b/subprojects/websocketpp/websocketpp/common/network.hpp
new file mode 100644
index 000000000..26a4cb9ea
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/network.hpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_NETWORK_HPP
+#define WEBSOCKETPP_COMMON_NETWORK_HPP
+
+// For ntohs and htons
+#if defined(_WIN32)
+    #include <winsock2.h>
+#else
+    //#include <arpa/inet.h>
+    #include <netinet/in.h>
+#endif
+
+#include <websocketpp/common/stdint.hpp>
+
+namespace websocketpp {
+namespace lib {
+namespace net {
+
+inline bool is_little_endian() {
+    short int val = 0x1;
+    char *ptr = reinterpret_cast<char *>(&val);
+    return (ptr[0] == 1);
+}
+
+#define TYP_INIT 0
+#define TYP_SMLE 1
+#define TYP_BIGE 2
+
+/// Convert 64 bit value to network byte order
+/**
+ * This method is prefixed to avoid conflicts with operating system level
+ * macros for this functionality.
+ *
+ * TODO: figure out if it would be beneficial to use operating system level
+ * macros for this.
+ *
+ * @param src The integer in host byte order
+ * @return src converted to network byte order
+ */
+inline uint64_t _htonll(uint64_t src) {
+    static int typ = TYP_INIT;
+    unsigned char c;
+    union {
+        uint64_t ull;
+        unsigned char c[8];
+    } x;
+    if (typ == TYP_INIT) {
+        x.ull = 0x01;
+        typ = (x.c[7] == 0x01ULL) ? TYP_BIGE : TYP_SMLE;
+    }
+    if (typ == TYP_BIGE)
+        return src;
+    x.ull = src;
+    c = x.c[0]; x.c[0] = x.c[7]; x.c[7] = c;
+    c = x.c[1]; x.c[1] = x.c[6]; x.c[6] = c;
+    c = x.c[2]; x.c[2] = x.c[5]; x.c[5] = c;
+    c = x.c[3]; x.c[3] = x.c[4]; x.c[4] = c;
+    return x.ull;
+}
+
+/// Convert 64 bit value to host byte order
+/**
+ * This method is prefixed to avoid conflicts with operating system level
+ * macros for this functionality.
+ *
+ * TODO: figure out if it would be beneficial to use operating system level
+ * macros for this.
+ *
+ * @param src The integer in network byte order
+ * @return src converted to host byte order
+ */
+inline uint64_t _ntohll(uint64_t src) {
+    return _htonll(src);
+}
+
+} // net
+} // lib
+} // websocketpp
+
+#endif // WEBSOCKETPP_COMMON_NETWORK_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/platforms.hpp b/subprojects/websocketpp/websocketpp/common/platforms.hpp
new file mode 100644
index 000000000..877985777
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/platforms.hpp
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_PLATFORMS_HPP
+#define WEBSOCKETPP_COMMON_PLATFORMS_HPP
+
+/**
+ * This header contains any platform specific preprocessor adjustments that
+ * don't fit somewhere else better.
+ */
+
+#if defined(_WIN32) && !defined(NOMINMAX)
+    // don't define min and max macros that conflict with std::min and std::max
+    #define NOMINMAX
+#endif
+
+// Bump up the variadic parameter max for Visual Studio 2012
+#if defined(_MSC_VER) && _MSC_VER == 1700
+    #define _VARIADIC_MAX 8
+#endif
+
+#endif // WEBSOCKETPP_COMMON_PLATFORMS_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/random.hpp b/subprojects/websocketpp/websocketpp/common/random.hpp
new file mode 100644
index 000000000..ddf996941
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/random.hpp
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_RANDOM_DEVICE_HPP
+#define WEBSOCKETPP_COMMON_RANDOM_DEVICE_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+
+// If we've determined that we're in full C++11 mode and the user hasn't
+// explicitly disabled the use of C++11 random header, then prefer it to
+// boost.
+#if defined _WEBSOCKETPP_CPP11_INTERNAL_ && !defined _WEBSOCKETPP_NO_CPP11_RANDOM_DEVICE_
+    #ifndef _WEBSOCKETPP_CPP11_RANDOM_DEVICE_
+        #define _WEBSOCKETPP_CPP11_RANDOM_DEVICE_
+    #endif
+#endif
+
+
+// If we're on Visual Studio 2010 or higher and haven't explicitly disabled
+// the use of C++11 random header then prefer it to boost.
+#if defined(_MSC_VER) && _MSC_VER >= 1600 && !defined _WEBSOCKETPP_NO_CPP11_MEMORY_
+    #ifndef _WEBSOCKETPP_CPP11_MEMORY_
+        #define _WEBSOCKETPP_CPP11_MEMORY_
+    #endif
+#endif
+
+
+
+#ifdef _WEBSOCKETPP_CPP11_RANDOM_DEVICE_
+    #include <random>
+#else
+    #include <boost/version.hpp>
+
+    #if (BOOST_VERSION/100000) == 1 && ((BOOST_VERSION/100)%1000) > 46
+        #include <boost/random/uniform_int_distribution.hpp>
+        #include <boost/random/random_device.hpp>
+    #elif (BOOST_VERSION/100000) == 1 && ((BOOST_VERSION/100)%1000) >= 43
+        #include <boost/nondet_random.hpp>
+    #else
+        // TODO: static_assert(false, "Could not find a suitable random_device")
+    #endif
+#endif
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef _WEBSOCKETPP_CPP11_RANDOM_DEVICE_
+    using std::random_device;
+    using std::uniform_int_distribution;
+#else
+    using boost::random::random_device;
+    using boost::random::uniform_int_distribution;
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_RANDOM_DEVICE_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/regex.hpp b/subprojects/websocketpp/websocketpp/common/regex.hpp
new file mode 100644
index 000000000..326635de2
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/regex.hpp
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_REGEX_HPP
+#define WEBSOCKETPP_COMMON_REGEX_HPP
+
+#if defined _WEBSOCKETPP_CPP11_STL_ && !defined _WEBSOCKETPP_NO_CPP11_REGEX_
+    #ifndef _WEBSOCKETPP_CPP11_REGEX_
+        #define _WEBSOCKETPP_CPP11_REGEX_
+    #endif
+#endif
+
+#ifdef _WEBSOCKETPP_CPP11_REGEX_
+    #include <regex>
+#else
+    #include <boost/regex.hpp>
+#endif
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef _WEBSOCKETPP_CPP11_REGEX_
+    using std::cmatch;
+    using std::regex;
+    using std::regex_match;
+#else
+    using boost::cmatch;
+    using boost::regex;
+    using boost::regex_match;
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_REGEX_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/stdint.hpp b/subprojects/websocketpp/websocketpp/common/stdint.hpp
new file mode 100644
index 000000000..ec48ea75b
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/stdint.hpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_STDINT_HPP
+#define WEBSOCKETPP_COMMON_STDINT_HPP
+
+#ifndef __STDC_LIMIT_MACROS
+    #define __STDC_LIMIT_MACROS 1
+#endif
+
+#if defined (_WIN32) && defined (_MSC_VER) && (_MSC_VER < 1600)
+    #include <boost/cstdint.hpp>
+
+    using boost::int8_t;
+    using boost::int_least8_t;
+    using boost::int_fast8_t;
+    using boost::uint8_t;
+    using boost::uint_least8_t;
+    using boost::uint_fast8_t;
+
+    using boost::int16_t;
+    using boost::int_least16_t;
+    using boost::int_fast16_t;
+    using boost::uint16_t;
+    using boost::uint_least16_t;
+    using boost::uint_fast16_t;
+
+    using boost::int32_t;
+    using boost::int_least32_t;
+    using boost::int_fast32_t;
+    using boost::uint32_t;
+    using boost::uint_least32_t;
+    using boost::uint_fast32_t;
+
+    #ifndef BOOST_NO_INT64_T
+    using boost::int64_t;
+    using boost::int_least64_t;
+    using boost::int_fast64_t;
+    using boost::uint64_t;
+    using boost::uint_least64_t;
+    using boost::uint_fast64_t;
+    #endif
+    using boost::intmax_t;
+    using boost::uintmax_t;
+#else
+    #include <stdint.h>
+#endif
+
+#endif // WEBSOCKETPP_COMMON_STDINT_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/system_error.hpp b/subprojects/websocketpp/websocketpp/common/system_error.hpp
new file mode 100644
index 000000000..e5aea2549
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/system_error.hpp
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_SYSTEM_ERROR_HPP
+#define WEBSOCKETPP_COMMON_SYSTEM_ERROR_HPP
+
+
+#include <websocketpp/common/cpp11.hpp>
+
+// If we've determined that we're in full C++11 mode and the user hasn't
+// explicitly disabled the use of C++11 system_error header, then prefer it to
+// boost.
+#if defined _WEBSOCKETPP_CPP11_INTERNAL_ && !defined _WEBSOCKETPP_NO_CPP11_SYSTEM_ERROR_
+    #ifndef _WEBSOCKETPP_CPP11_SYSTEM_ERROR_
+        #define _WEBSOCKETPP_CPP11_SYSTEM_ERROR_
+    #endif
+#endif
+
+// If we're on Visual Studio 2010 or higher and haven't explicitly disabled
+// the use of C++11 system_error header then prefer it to boost.
+#if defined(_MSC_VER) && _MSC_VER >= 1600 && !defined _WEBSOCKETPP_NO_CPP11_SYSTEM_ERROR_
+    #ifndef _WEBSOCKETPP_CPP11_SYSTEM_ERROR_
+        #define _WEBSOCKETPP_CPP11_SYSTEM_ERROR_
+    #endif
+#endif
+
+
+
+#ifdef _WEBSOCKETPP_CPP11_SYSTEM_ERROR_
+    #include <system_error>
+#else
+    #include <boost/system/error_code.hpp>
+    #include <boost/system/system_error.hpp>
+#endif
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef _WEBSOCKETPP_CPP11_SYSTEM_ERROR_
+    using std::errc;
+    using std::error_code;
+    using std::error_category;
+    using std::error_condition;
+    using std::system_error;
+    #define _WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_ namespace std {
+    #define _WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_ }
+#else
+    namespace errc = boost::system::errc;
+    using boost::system::error_code;
+    using boost::system::error_category;
+    using boost::system::error_condition;
+    using boost::system::system_error;
+    #define _WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_ namespace boost { namespace system {
+    #define _WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_ }}
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_SYSTEM_ERROR_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/thread.hpp b/subprojects/websocketpp/websocketpp/common/thread.hpp
new file mode 100644
index 000000000..9cf959ce0
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/thread.hpp
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_THREAD_HPP
+#define WEBSOCKETPP_COMMON_THREAD_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+
+// If we autodetect C++11 and haven't been explicitly instructed to not use
+// C++11 threads, then set the defines that instructs the rest of this header
+// to use C++11 <thread> and <mutex>
+#if defined _WEBSOCKETPP_CPP11_INTERNAL_ && !defined _WEBSOCKETPP_NO_CPP11_THREAD_
+    // MinGW by default does not support C++11 thread/mutex so even if the
+    // internal check for C++11 passes, ignore it if we are on MinGW
+    #if (!defined(__MINGW32__) && !defined(__MINGW64__)) || __MINGW64_VERSION_MAJOR>=6
+        #ifndef _WEBSOCKETPP_CPP11_THREAD_
+            #define _WEBSOCKETPP_CPP11_THREAD_
+        #endif
+    #endif
+#endif
+
+// If we're on Visual Studio 2013 or higher and haven't explicitly disabled
+// the use of C++11 thread header then prefer it to boost.
+#if defined(_MSC_VER) && _MSC_VER >= 1800 && !defined _WEBSOCKETPP_NO_CPP11_THREAD_
+    #ifndef _WEBSOCKETPP_CPP11_THREAD_
+        #define _WEBSOCKETPP_CPP11_THREAD_
+    #endif
+#endif
+
+#if defined(_WEBSOCKETPP_MINGW_THREAD_)
+    #include <mingw-threads/mingw.thread.h>
+    #include <mingw-threads/mingw.mutex.h>
+    #include <mingw-threads/mingw.condition_variable.h>
+#elif defined(_WEBSOCKETPP_CPP11_THREAD_)
+    #include <thread>
+    #include <mutex>
+    #include <condition_variable>
+#else
+    #include <boost/thread.hpp>
+    #include <boost/thread/mutex.hpp>
+    #include <boost/thread/condition_variable.hpp>
+#endif
+
+namespace websocketpp {
+namespace lib {
+
+#if defined(_WEBSOCKETPP_CPP11_THREAD_) || defined(_WEBSOCKETPP_MINGW_THREAD_)
+    using std::mutex;
+    using std::lock_guard;
+    using std::thread;
+    using std::unique_lock;
+    using std::condition_variable;
+#else
+    using boost::mutex;
+    using boost::lock_guard;
+    using boost::thread;
+    using boost::unique_lock;
+    using boost::condition_variable;
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_THREAD_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/time.hpp b/subprojects/websocketpp/websocketpp/common/time.hpp
new file mode 100644
index 000000000..571688e1b
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/time.hpp
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_TIME_HPP
+#define WEBSOCKETPP_COMMON_TIME_HPP
+
+#include <ctime>
+
+namespace websocketpp {
+namespace lib {
+
+// Code in this header was inspired by the following article and includes some
+// code from the related project g2log. The g2log code is public domain licensed
+// http://kjellkod.wordpress.com/2013/01/22/exploring-c11-part-2-localtime-and-time-again/
+
+/// Thread safe cross platform localtime
+inline std::tm localtime(std::time_t const & time) {
+    std::tm tm_snapshot;
+#if (defined(__MINGW32__) || defined(__MINGW64__))
+    memcpy(&tm_snapshot, ::localtime(&time), sizeof(std::tm));
+#elif (defined(WIN32) || defined(_WIN32) || defined(__WIN32__))
+    localtime_s(&tm_snapshot, &time); 
+#else
+    localtime_r(&time, &tm_snapshot); // POSIX  
+#endif
+    return tm_snapshot;
+}
+
+} // lib
+} // websocketpp
+
+#endif // WEBSOCKETPP_COMMON_TIME_HPP
diff --git a/subprojects/websocketpp/websocketpp/common/type_traits.hpp b/subprojects/websocketpp/websocketpp/common/type_traits.hpp
new file mode 100644
index 000000000..c89b82b31
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/common/type_traits.hpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_COMMON_TYPE_TRAITS_HPP
+#define WEBSOCKETPP_COMMON_TYPE_TRAITS_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+
+// If we've determined that we're in full C++11 mode and the user hasn't
+// explicitly disabled the use of C++11 functional header, then prefer it to
+// boost.
+#if defined _WEBSOCKETPP_CPP11_INTERNAL_ && !defined _WEBSOCKETPP_NO_CPP11_TYPE_TRAITS_
+    #ifndef _WEBSOCKETPP_CPP11_TYPE_TRAITS_
+        #define _WEBSOCKETPP_CPP11_TYPE_TRAITS_
+    #endif
+#endif
+
+
+#ifdef _WEBSOCKETPP_CPP11_TYPE_TRAITS_
+    #include <type_traits>
+#else
+    #include <boost/aligned_storage.hpp>
+#endif
+
+
+
+namespace websocketpp {
+namespace lib {
+
+#ifdef _WEBSOCKETPP_CPP11_TYPE_TRAITS_
+    using std::aligned_storage;
+    using std::is_same;
+#else
+    using boost::aligned_storage;
+    using boost::is_same;
+#endif
+
+} // namespace lib
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_COMMON_TYPE_TRAITS_HPP
diff --git a/subprojects/websocketpp/websocketpp/concurrency/basic.hpp b/subprojects/websocketpp/websocketpp/concurrency/basic.hpp
new file mode 100644
index 000000000..1943ad77a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/concurrency/basic.hpp
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONCURRENCY_BASIC_HPP
+#define WEBSOCKETPP_CONCURRENCY_BASIC_HPP
+
+#include <websocketpp/common/thread.hpp>
+
+namespace websocketpp {
+namespace concurrency {
+
+/// Concurrency policy that uses std::mutex / boost::mutex
+class basic {
+public:
+    typedef lib::mutex mutex_type;
+    typedef lib::lock_guard<mutex_type> scoped_lock_type;
+};
+
+} // namespace concurrency
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONCURRENCY_BASIC_HPP
diff --git a/subprojects/websocketpp/websocketpp/concurrency/none.hpp b/subprojects/websocketpp/websocketpp/concurrency/none.hpp
new file mode 100644
index 000000000..da9aa4112
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/concurrency/none.hpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONCURRENCY_NONE_HPP
+#define WEBSOCKETPP_CONCURRENCY_NONE_HPP
+
+namespace websocketpp {
+
+/// Concurrency handling support
+namespace concurrency {
+
+/// Implementation for no-op locking primitives
+namespace none_impl {
+/// A fake mutex implementation that does nothing
+class fake_mutex {
+public:
+    fake_mutex() {}
+    ~fake_mutex() {}
+};
+
+/// A fake lock guard implementation that does nothing
+class fake_lock_guard {
+public:
+    explicit fake_lock_guard(fake_mutex) {}
+    ~fake_lock_guard() {}
+};
+} // namespace none_impl
+
+/// Stub concurrency policy that implements the interface using no-ops.
+/**
+ * This policy documents the concurrency policy interface using no-ops. It can
+ * be used as a reference or base for building a new concurrency policy. It can
+ * also be used as is to disable all locking for endpoints used in purely single
+ * threaded programs.
+ */
+class none {
+public:
+    /// The type of a mutex primitive
+    /**
+     * std::mutex is an example.
+     */
+    typedef none_impl::fake_mutex mutex_type;
+
+    /// The type of a scoped/RAII lock primitive.
+    /**
+     * The scoped lock constructor should take a mutex_type as a parameter,
+     * acquire that lock, and release it in its destructor. std::lock_guard is
+     * an example.
+     */
+    typedef none_impl::fake_lock_guard scoped_lock_type;
+};
+
+} // namespace concurrency
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONCURRENCY_ASYNC_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/asio.hpp b/subprojects/websocketpp/websocketpp/config/asio.hpp
new file mode 100644
index 000000000..d28d0fb80
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/asio.hpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_ASIO_TLS_HPP
+#define WEBSOCKETPP_CONFIG_ASIO_TLS_HPP
+
+#include <websocketpp/config/core.hpp>
+#include <websocketpp/transport/asio/endpoint.hpp>
+#include <websocketpp/transport/asio/security/tls.hpp>
+
+// Pull in non-tls config
+#include <websocketpp/config/asio_no_tls.hpp>
+
+// Define TLS config
+namespace websocketpp {
+namespace config {
+
+/// Server config with asio transport and TLS enabled
+struct asio_tls : public core {
+    typedef asio_tls type;
+    typedef core base;
+
+    typedef base::concurrency_type concurrency_type;
+
+    typedef base::request_type request_type;
+    typedef base::response_type response_type;
+
+    typedef base::message_type message_type;
+    typedef base::con_msg_manager_type con_msg_manager_type;
+    typedef base::endpoint_msg_manager_type endpoint_msg_manager_type;
+
+    typedef base::alog_type alog_type;
+    typedef base::elog_type elog_type;
+
+    typedef base::rng_type rng_type;
+
+    struct transport_config : public base::transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::alog_type alog_type;
+        typedef type::elog_type elog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+        typedef websocketpp::transport::asio::tls_socket::endpoint socket_type;
+    };
+
+    typedef websocketpp::transport::asio::endpoint<transport_config>
+        transport_type;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_ASIO_TLS_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/asio_client.hpp b/subprojects/websocketpp/websocketpp/config/asio_client.hpp
new file mode 100644
index 000000000..1cb594d0a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/asio_client.hpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_ASIO_TLS_CLIENT_HPP
+#define WEBSOCKETPP_CONFIG_ASIO_TLS_CLIENT_HPP
+
+#include <websocketpp/config/core_client.hpp>
+#include <websocketpp/transport/asio/endpoint.hpp>
+#include <websocketpp/transport/asio/security/tls.hpp>
+
+// Pull in non-tls config
+#include <websocketpp/config/asio_no_tls_client.hpp>
+
+// Define TLS config
+namespace websocketpp {
+namespace config {
+
+/// Client config with asio transport and TLS enabled
+struct asio_tls_client : public core_client {
+    typedef asio_tls_client type;
+    typedef core_client base;
+
+    typedef base::concurrency_type concurrency_type;
+
+    typedef base::request_type request_type;
+    typedef base::response_type response_type;
+
+    typedef base::message_type message_type;
+    typedef base::con_msg_manager_type con_msg_manager_type;
+    typedef base::endpoint_msg_manager_type endpoint_msg_manager_type;
+
+    typedef base::alog_type alog_type;
+    typedef base::elog_type elog_type;
+
+    typedef base::rng_type rng_type;
+
+    struct transport_config : public base::transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::alog_type alog_type;
+        typedef type::elog_type elog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+        typedef websocketpp::transport::asio::tls_socket::endpoint socket_type;
+    };
+
+    typedef websocketpp::transport::asio::endpoint<transport_config>
+        transport_type;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_ASIO_TLS_CLIENT_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/asio_no_tls.hpp b/subprojects/websocketpp/websocketpp/config/asio_no_tls.hpp
new file mode 100644
index 000000000..6c1357fba
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/asio_no_tls.hpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_ASIO_HPP
+#define WEBSOCKETPP_CONFIG_ASIO_HPP
+
+#include <websocketpp/config/core.hpp>
+#include <websocketpp/transport/asio/endpoint.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Server config with asio transport and TLS disabled
+struct asio : public core {
+    typedef asio type;
+    typedef core base;
+
+    typedef base::concurrency_type concurrency_type;
+
+    typedef base::request_type request_type;
+    typedef base::response_type response_type;
+
+    typedef base::message_type message_type;
+    typedef base::con_msg_manager_type con_msg_manager_type;
+    typedef base::endpoint_msg_manager_type endpoint_msg_manager_type;
+
+    typedef base::alog_type alog_type;
+    typedef base::elog_type elog_type;
+
+    typedef base::rng_type rng_type;
+
+    struct transport_config : public base::transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::alog_type alog_type;
+        typedef type::elog_type elog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+        typedef websocketpp::transport::asio::basic_socket::endpoint
+            socket_type;
+    };
+
+    typedef websocketpp::transport::asio::endpoint<transport_config>
+        transport_type;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_ASIO_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/asio_no_tls_client.hpp b/subprojects/websocketpp/websocketpp/config/asio_no_tls_client.hpp
new file mode 100644
index 000000000..6e3f7ba0e
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/asio_no_tls_client.hpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_ASIO_CLIENT_HPP
+#define WEBSOCKETPP_CONFIG_ASIO_CLIENT_HPP
+
+#include <websocketpp/config/core_client.hpp>
+#include <websocketpp/transport/asio/endpoint.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Client config with asio transport and TLS disabled
+struct asio_client : public core_client {
+    typedef asio_client type;
+    typedef core_client base;
+
+    typedef base::concurrency_type concurrency_type;
+
+    typedef base::request_type request_type;
+    typedef base::response_type response_type;
+
+    typedef base::message_type message_type;
+    typedef base::con_msg_manager_type con_msg_manager_type;
+    typedef base::endpoint_msg_manager_type endpoint_msg_manager_type;
+
+    typedef base::alog_type alog_type;
+    typedef base::elog_type elog_type;
+
+    typedef base::rng_type rng_type;
+
+    struct transport_config : public base::transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::alog_type alog_type;
+        typedef type::elog_type elog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+        typedef websocketpp::transport::asio::basic_socket::endpoint
+            socket_type;
+    };
+
+    typedef websocketpp::transport::asio::endpoint<transport_config>
+        transport_type;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_ASIO_CLIENT_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/boost_config.hpp b/subprojects/websocketpp/websocketpp/config/boost_config.hpp
new file mode 100644
index 000000000..57671ccda
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/boost_config.hpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+ // This header defines WebSocket++ macros for C++11 compatibility based on the 
+ // Boost.Config library. This will correctly configure most target platforms
+ // simply by including this header before any other WebSocket++ header.
+
+#ifndef WEBSOCKETPP_CONFIG_BOOST_CONFIG_HPP
+#define WEBSOCKETPP_CONFIG_BOOST_CONFIG_HPP
+
+#include <boost/config.hpp>
+
+//  _WEBSOCKETPP_CPP11_MEMORY_ and _WEBSOCKETPP_CPP11_FUNCTIONAL_ presently
+//  only work if either both or neither is defined.
+#if !defined BOOST_NO_CXX11_SMART_PTR && !defined BOOST_NO_CXX11_HDR_FUNCTIONAL
+    #define _WEBSOCKETPP_CPP11_MEMORY_
+    #define _WEBSOCKETPP_CPP11_FUNCTIONAL_
+#endif
+
+#ifdef BOOST_ASIO_HAS_STD_CHRONO
+    #define _WEBSOCKETPP_CPP11_CHRONO_
+#endif
+
+#ifndef BOOST_NO_CXX11_HDR_RANDOM
+    #define _WEBSOCKETPP_CPP11_RANDOM_DEVICE_
+#endif
+
+#ifndef BOOST_NO_CXX11_HDR_REGEX
+    #define _WEBSOCKETPP_CPP11_REGEX_
+#endif
+
+#ifndef BOOST_NO_CXX11_HDR_SYSTEM_ERROR
+    #define _WEBSOCKETPP_CPP11_SYSTEM_ERROR_
+#endif
+
+#ifndef BOOST_NO_CXX11_HDR_THREAD
+    #define _WEBSOCKETPP_CPP11_THREAD_
+#endif
+
+#ifndef BOOST_NO_CXX11_HDR_INITIALIZER_LIST
+    #define _WEBSOCKETPP_INITIALIZER_LISTS_
+#endif
+
+#define _WEBSOCKETPP_NOEXCEPT_TOKEN_  BOOST_NOEXCEPT
+#define _WEBSOCKETPP_CONSTEXPR_TOKEN_  BOOST_CONSTEXPR
+// TODO: nullptr support
+
+#endif // WEBSOCKETPP_CONFIG_BOOST_CONFIG_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/core.hpp b/subprojects/websocketpp/websocketpp/config/core.hpp
new file mode 100644
index 000000000..93981aa0e
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/core.hpp
@@ -0,0 +1,297 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_CORE_HPP
+#define WEBSOCKETPP_CONFIG_CORE_HPP
+
+// Non-Policy common stuff
+#include <websocketpp/common/platforms.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/stdint.hpp>
+
+// Concurrency
+#include <websocketpp/concurrency/basic.hpp>
+
+// Transport
+#include <websocketpp/transport/iostream/endpoint.hpp>
+
+// HTTP
+#include <websocketpp/http/request.hpp>
+#include <websocketpp/http/response.hpp>
+
+// Messages
+#include <websocketpp/message_buffer/message.hpp>
+#include <websocketpp/message_buffer/alloc.hpp>
+
+// Loggers
+#include <websocketpp/logger/basic.hpp>
+#include <websocketpp/logger/levels.hpp>
+
+// RNG
+#include <websocketpp/random/none.hpp>
+
+// User stub base classes
+#include <websocketpp/endpoint_base.hpp>
+#include <websocketpp/connection_base.hpp>
+
+// Extensions
+#include <websocketpp/extensions/permessage_deflate/disabled.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Server config with iostream transport
+struct core {
+    typedef core type;
+
+    // Concurrency policy
+    typedef websocketpp::concurrency::basic concurrency_type;
+
+    // HTTP Parser Policies
+    typedef http::parser::request request_type;
+    typedef http::parser::response response_type;
+
+    // Message Policies
+    typedef message_buffer::message<message_buffer::alloc::con_msg_manager>
+        message_type;
+    typedef message_buffer::alloc::con_msg_manager<message_type>
+        con_msg_manager_type;
+    typedef message_buffer::alloc::endpoint_msg_manager<con_msg_manager_type>
+        endpoint_msg_manager_type;
+
+    /// Logging policies
+    typedef websocketpp::log::basic<concurrency_type,
+        websocketpp::log::elevel> elog_type;
+    typedef websocketpp::log::basic<concurrency_type,
+        websocketpp::log::alevel> alog_type;
+
+    /// RNG policies
+    typedef websocketpp::random::none::int_generator<uint32_t> rng_type;
+
+    /// Controls compile time enabling/disabling of thread syncronization
+    /// code Disabling can provide a minor performance improvement to single
+    /// threaded applications
+    static bool const enable_multithreading = true;
+
+    struct transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::elog_type elog_type;
+        typedef type::alog_type alog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+
+        /// Controls compile time enabling/disabling of thread syncronization
+        /// code Disabling can provide a minor performance improvement to single
+        /// threaded applications
+        static bool const enable_multithreading = true;
+
+        /// Default timer values (in ms)
+
+        /// Length of time to wait for socket pre-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use
+         */
+        static const long timeout_socket_pre_init = 5000;
+
+        /// Length of time to wait before a proxy handshake is aborted
+        static const long timeout_proxy = 5000;
+
+        /// Length of time to wait for socket post-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use.
+         * Often this means the TLS handshake
+         */
+        static const long timeout_socket_post_init = 5000;
+
+        /// Length of time to wait for dns resolution
+        static const long timeout_dns_resolve = 5000;
+
+        /// Length of time to wait for TCP connect
+        static const long timeout_connect = 5000;
+
+        /// Length of time to wait for socket shutdown
+        static const long timeout_socket_shutdown = 5000;
+    };
+
+    /// Transport Endpoint Component
+    typedef websocketpp::transport::iostream::endpoint<transport_config>
+        transport_type;
+
+    /// User overridable Endpoint base class
+    typedef websocketpp::endpoint_base endpoint_base;
+    /// User overridable Connection base class
+    typedef websocketpp::connection_base connection_base;
+
+    /// Default timer values (in ms)
+
+    /// Length of time before an opening handshake is aborted
+    static const long timeout_open_handshake = 5000;
+    /// Length of time before a closing handshake is aborted
+    static const long timeout_close_handshake = 5000;
+    /// Length of time to wait for a pong after a ping
+    static const long timeout_pong = 5000;
+
+    /// WebSocket Protocol version to use as a client
+    /**
+     * What version of the WebSocket Protocol to use for outgoing client
+     * connections. Setting this to a value other than 13 (RFC6455) is not
+     * recommended.
+     */
+    static const int client_version = 13; // RFC6455
+
+    /// Default static error logging channels
+    /**
+     * Which error logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level errors
+     */
+    static const websocketpp::log::level elog_level =
+        websocketpp::log::elevel::all ^ websocketpp::log::elevel::devel;
+
+    /// Default static access logging channels
+    /**
+     * Which access logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level access messages
+     */
+    static const websocketpp::log::level alog_level =
+        websocketpp::log::alevel::all ^ websocketpp::log::alevel::devel;
+
+    /// Size of the per-connection read buffer
+    /**
+     * Each connection has an internal buffer of this size. A larger value will
+     * result in fewer trips through the library and less CPU overhead at the
+     * expense of increased memory usage per connection.
+     *
+     * If your application primarily deals in very large messages you may want
+     * to try setting this value higher.
+     *
+     * If your application has a lot of connections or primarily deals in small
+     * messages you may want to try setting this smaller.
+     */
+    static const size_t connection_read_buffer_size = 16384;
+
+    /// Drop connections immediately on protocol error.
+    /**
+     * Drop connections on protocol error rather than sending a close frame.
+     * Off by default. This may result in legit messages near the error being
+     * dropped as well. It may free up resources otherwise spent dealing with
+     * misbehaving clients.
+     */
+    static const bool drop_on_protocol_error = false;
+
+    /// Suppresses the return of detailed connection close information
+    /**
+     * Silence close suppresses the return of detailed connection close
+     * information during the closing handshake. This information is useful
+     * for debugging and presenting useful errors to end users but may be
+     * undesirable for security reasons in some production environments.
+     * Close reasons could be used by an attacker to confirm that the endpoint
+     * is out of resources or be used to identify the WebSocket implementation
+     * in use.
+     *
+     * Note: this will suppress *all* close codes, including those explicitly
+     * sent by local applications.
+     */
+    static const bool silent_close = false;
+
+    /// Default maximum message size
+    /**
+     * Default value for the processor's maximum message size. Maximum message size
+     * determines the point at which the library will fail a connection with the 
+     * message_too_big protocol error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.3.0
+     */
+    static const size_t max_message_size = 32000000;
+    
+    /// Default maximum http body size
+    /**
+     * Default value for the http parser's maximum body size. Maximum body size
+     * determines the point at which the library will abort reading an HTTP
+     * connection with the 413/request entity too large error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.5.0
+     */
+    static const size_t max_http_body_size = 32000000;
+
+    /// Global flag for enabling/disabling extensions
+    static const bool enable_extensions = true;
+
+    /// Extension specific settings:
+
+    /// permessage_compress extension
+    struct permessage_deflate_config {
+        typedef core::request_type request_type;
+
+        /// If the remote endpoint requests that we reset the compression
+        /// context after each message should we honor the request?
+        static const bool allow_disabling_context_takeover = true;
+
+        /// If the remote endpoint requests that we reduce the size of the
+        /// LZ77 sliding window size this is the lowest value that will be
+        /// allowed. Values range from 8 to 15. A value of 8 means we will
+        /// allow any possible window size. A value of 15 means do not allow
+        /// negotiation of the window size (ie require the default).
+        static const uint8_t minimum_outgoing_window_bits = 8;
+    };
+
+    typedef websocketpp::extensions::permessage_deflate::disabled
+        <permessage_deflate_config> permessage_deflate_type;
+
+    /// Autonegotiate permessage-deflate
+    /**
+     * Automatically enables the permessage-deflate extension.
+     *
+     * For clients this results in a permessage-deflate extension request being
+     * sent with every request rather than requiring it to be requested manually
+     *
+     * For servers this results in accepting the first set of extension settings
+     * requested by the client that we understand being used. The alternative is
+     * requiring the extension to be manually negotiated in `validate`. With
+     * auto-negotiate on, you may still override the auto-negotiate manually if
+     * needed.
+     */
+    //static const bool autonegotiate_compression = false;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_CORE_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/core_client.hpp b/subprojects/websocketpp/websocketpp/config/core_client.hpp
new file mode 100644
index 000000000..dadf8a4e7
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/core_client.hpp
@@ -0,0 +1,294 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_CORE_CLIENT_HPP
+#define WEBSOCKETPP_CONFIG_CORE_CLIENT_HPP
+
+// Non-Policy common stuff
+#include <websocketpp/common/platforms.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/stdint.hpp>
+
+// Concurrency
+#ifndef _WEBSOCKETPP_NO_THREADING_
+#include <websocketpp/concurrency/basic.hpp>
+#else
+#include <websocketpp/concurrency/none.hpp>
+#endif
+
+// Transport
+#include <websocketpp/transport/iostream/endpoint.hpp>
+
+// HTTP
+#include <websocketpp/http/request.hpp>
+#include <websocketpp/http/response.hpp>
+
+// Messages
+#include <websocketpp/message_buffer/message.hpp>
+#include <websocketpp/message_buffer/alloc.hpp>
+
+// Loggers
+#include <websocketpp/logger/basic.hpp>
+
+// RNG
+#include <websocketpp/random/random_device.hpp>
+
+// User stub base classes
+#include <websocketpp/endpoint_base.hpp>
+#include <websocketpp/connection_base.hpp>
+
+// Extensions
+#include <websocketpp/extensions/permessage_deflate/disabled.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Client config with iostream transport
+struct core_client {
+    typedef core_client type;
+
+    // Concurrency policy
+#ifndef _WEBSOCKETPP_NO_THREADING_
+    typedef websocketpp::concurrency::basic concurrency_type;
+#else
+    typedef websocketpp::concurrency::none concurrency_type;
+#endif
+
+    // HTTP Parser Policies
+    typedef http::parser::request request_type;
+    typedef http::parser::response response_type;
+
+    // Message Policies
+    typedef message_buffer::message<message_buffer::alloc::con_msg_manager>
+        message_type;
+    typedef message_buffer::alloc::con_msg_manager<message_type>
+        con_msg_manager_type;
+    typedef message_buffer::alloc::endpoint_msg_manager<con_msg_manager_type>
+        endpoint_msg_manager_type;
+
+    /// Logging policies
+    typedef websocketpp::log::basic<concurrency_type,
+        websocketpp::log::elevel> elog_type;
+    typedef websocketpp::log::basic<concurrency_type,
+        websocketpp::log::alevel> alog_type;
+
+    /// RNG policies
+    typedef websocketpp::random::random_device::int_generator<uint32_t,
+        concurrency_type> rng_type;
+
+    /// Controls compile time enabling/disabling of thread syncronization code
+    /// Disabling can provide a minor performance improvement to single threaded
+    /// applications
+    static bool const enable_multithreading = true;
+
+    struct transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::elog_type elog_type;
+        typedef type::alog_type alog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+
+        /// Controls compile time enabling/disabling of thread syncronization
+        /// code Disabling can provide a minor performance improvement to single
+        /// threaded applications
+        static bool const enable_multithreading = true;
+
+        /// Default timer values (in ms)
+
+        /// Length of time to wait for socket pre-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use
+         */
+        static const long timeout_socket_pre_init = 5000;
+
+        /// Length of time to wait before a proxy handshake is aborted
+        static const long timeout_proxy = 5000;
+
+        /// Length of time to wait for socket post-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use.
+         * Often this means the TLS handshake
+         */
+        static const long timeout_socket_post_init = 5000;
+
+        /// Length of time to wait for dns resolution
+        static const long timeout_dns_resolve = 5000;
+
+        /// Length of time to wait for TCP connect
+        static const long timeout_connect = 5000;
+
+        /// Length of time to wait for socket shutdown
+        static const long timeout_socket_shutdown = 5000;
+    };
+
+    /// Transport Endpoint Component
+    typedef websocketpp::transport::iostream::endpoint<transport_config>
+        transport_type;
+
+    /// User overridable Endpoint base class
+    typedef websocketpp::endpoint_base endpoint_base;
+    /// User overridable Connection base class
+    typedef websocketpp::connection_base connection_base;
+
+    /// Default timer values (in ms)
+
+    /// Length of time before an opening handshake is aborted
+    static const long timeout_open_handshake = 5000;
+    /// Length of time before a closing handshake is aborted
+    static const long timeout_close_handshake = 5000;
+    /// Length of time to wait for a pong after a ping
+    static const long timeout_pong = 5000;
+
+    /// WebSocket Protocol version to use as a client
+    /**
+     * What version of the WebSocket Protocol to use for outgoing client
+     * connections. Setting this to a value other than 13 (RFC6455) is not
+     * recommended.
+     */
+    static const int client_version = 13; // RFC6455
+
+    /// Default static error logging channels
+    /**
+     * Which error logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level errors
+     */
+    static const websocketpp::log::level elog_level =
+        websocketpp::log::elevel::all ^ websocketpp::log::elevel::devel;
+
+    /// Default static access logging channels
+    /**
+     * Which access logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level access messages
+     */
+    static const websocketpp::log::level alog_level =
+        websocketpp::log::alevel::all ^ websocketpp::log::alevel::devel;
+
+    ///
+    static const size_t connection_read_buffer_size = 16384;
+
+    /// Drop connections immediately on protocol error.
+    /**
+     * Drop connections on protocol error rather than sending a close frame.
+     * Off by default. This may result in legit messages near the error being
+     * dropped as well. It may free up resources otherwise spent dealing with
+     * misbehaving clients.
+     */
+    static const bool drop_on_protocol_error = false;
+
+    /// Suppresses the return of detailed connection close information
+    /**
+     * Silence close suppresses the return of detailed connection close
+     * information during the closing handshake. This information is useful
+     * for debugging and presenting useful errors to end users but may be
+     * undesirable for security reasons in some production environments.
+     * Close reasons could be used by an attacker to confirm that the endpoint
+     * is out of resources or be used to identify the WebSocket implementation
+     * in use.
+     *
+     * Note: this will suppress *all* close codes, including those explicitly
+     * sent by local applications.
+     */
+    static const bool silent_close = false;
+
+    /// Default maximum message size
+    /**
+     * Default value for the processor's maximum message size. Maximum message size
+     * determines the point at which the library will fail a connection with the 
+     * message_too_big protocol error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.3.0
+     */
+    static const size_t max_message_size = 32000000;
+
+    /// Default maximum http body size
+    /**
+     * Default value for the http parser's maximum body size. Maximum body size
+     * determines the point at which the library will abort reading an HTTP
+     * connection with the 413/request entity too large error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.5.0
+     */
+    static const size_t max_http_body_size = 32000000;
+
+    /// Global flag for enabling/disabling extensions
+    static const bool enable_extensions = true;
+
+    /// Extension specific settings:
+
+    /// permessage_deflate extension
+    struct permessage_deflate_config {
+        typedef core_client::request_type request_type;
+
+        /// If the remote endpoint requests that we reset the compression
+        /// context after each message should we honor the request?
+        static const bool allow_disabling_context_takeover = true;
+
+        /// If the remote endpoint requests that we reduce the size of the
+        /// LZ77 sliding window size this is the lowest value that will be
+        /// allowed. Values range from 8 to 15. A value of 8 means we will
+        /// allow any possible window size. A value of 15 means do not allow
+        /// negotiation of the window size (ie require the default).
+        static const uint8_t minimum_outgoing_window_bits = 8;
+    };
+
+    typedef websocketpp::extensions::permessage_deflate::disabled
+        <permessage_deflate_config> permessage_deflate_type;
+
+    /// Autonegotiate permessage-compress
+    /**
+     * Automatically enables the permessage-compress extension.
+     *
+     * For clients this results in a permessage-compress extension request being
+     * sent with every request rather than requiring it to be requested manually
+     *
+     * For servers this results in accepting the first set of extension settings
+     * requested by the client that we understand being used. The alternative is
+     * requiring the extension to be manually negotiated in `validate`. With
+     * auto-negotiate on, you may still override the auto-negotiate manually if
+     * needed.
+     */
+    //static const bool autonegotiate_compression = false;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_CORE_CLIENT_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/debug.hpp b/subprojects/websocketpp/websocketpp/config/debug.hpp
new file mode 100644
index 000000000..223f72fbb
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/debug.hpp
@@ -0,0 +1,286 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_DEBUG_HPP
+#define WEBSOCKETPP_CONFIG_DEBUG_HPP
+
+
+
+// Non-Policy common stuff
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/stdint.hpp>
+
+// Concurrency
+#include <websocketpp/concurrency/basic.hpp>
+
+// Transport
+#include <websocketpp/transport/iostream/endpoint.hpp>
+
+// HTTP
+#include <websocketpp/http/request.hpp>
+#include <websocketpp/http/response.hpp>
+
+// Messages
+#include <websocketpp/message_buffer/message.hpp>
+#include <websocketpp/message_buffer/alloc.hpp>
+
+// Loggers
+#include <websocketpp/logger/basic.hpp>
+
+// RNG
+#include <websocketpp/random/none.hpp>
+
+// User stub base classes
+#include <websocketpp/endpoint_base.hpp>
+#include <websocketpp/connection_base.hpp>
+
+// Extensions
+#include <websocketpp/extensions/permessage_deflate/disabled.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Client/Server debug config with iostream transport
+struct debug_core {
+    typedef debug_core type;
+
+    // Concurrency policy
+    typedef websocketpp::concurrency::basic concurrency_type;
+
+    // HTTP Parser Policies
+    typedef http::parser::request request_type;
+    typedef http::parser::response response_type;
+
+    // Message Policies
+    typedef message_buffer::message<message_buffer::alloc::con_msg_manager>
+        message_type;
+    typedef message_buffer::alloc::con_msg_manager<message_type>
+        con_msg_manager_type;
+    typedef message_buffer::alloc::endpoint_msg_manager<con_msg_manager_type>
+        endpoint_msg_manager_type;
+
+    /// Logging policies
+    typedef websocketpp::log::basic<concurrency_type,
+        websocketpp::log::elevel> elog_type;
+    typedef websocketpp::log::basic<concurrency_type,
+        websocketpp::log::alevel> alog_type;
+
+    /// RNG policies
+    typedef websocketpp::random::none::int_generator<uint32_t> rng_type;
+
+    /// Controls compile time enabling/disabling of thread syncronization
+    /// code Disabling can provide a minor performance improvement to single
+    /// threaded applications
+    static bool const enable_multithreading = true;
+
+    struct transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::elog_type elog_type;
+        typedef type::alog_type alog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+
+        /// Controls compile time enabling/disabling of thread syncronization
+        /// code Disabling can provide a minor performance improvement to single
+        /// threaded applications
+        static bool const enable_multithreading = true;
+
+        /// Default timer values (in ms)
+
+        /// Length of time to wait for socket pre-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use
+         */
+        static const long timeout_socket_pre_init = 5000;
+
+        /// Length of time to wait before a proxy handshake is aborted
+        static const long timeout_proxy = 5000;
+
+        /// Length of time to wait for socket post-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use.
+         * Often this means the TLS handshake
+         */
+        static const long timeout_socket_post_init = 5000;
+
+        /// Length of time to wait for dns resolution
+        static const long timeout_dns_resolve = 5000;
+
+        /// Length of time to wait for TCP connect
+        static const long timeout_connect = 5000;
+
+        /// Length of time to wait for socket shutdown
+        static const long timeout_socket_shutdown = 5000;
+    };
+
+    /// Transport Endpoint Component
+    typedef websocketpp::transport::iostream::endpoint<transport_config>
+        transport_type;
+
+    /// User overridable Endpoint base class
+    typedef websocketpp::endpoint_base endpoint_base;
+    /// User overridable Connection base class
+    typedef websocketpp::connection_base connection_base;
+
+    /// Default timer values (in ms)
+
+    /// Length of time before an opening handshake is aborted
+    static const long timeout_open_handshake = 5000;
+    /// Length of time before a closing handshake is aborted
+    static const long timeout_close_handshake = 5000;
+    /// Length of time to wait for a pong after a ping
+    static const long timeout_pong = 5000;
+
+    /// WebSocket Protocol version to use as a client
+    /**
+     * What version of the WebSocket Protocol to use for outgoing client
+     * connections. Setting this to a value other than 13 (RFC6455) is not
+     * recommended.
+     */
+    static const int client_version = 13; // RFC6455
+
+    /// Default static error logging channels
+    /**
+     * Which error logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level errors
+     */
+    static const websocketpp::log::level elog_level =
+        websocketpp::log::elevel::all;
+
+    /// Default static access logging channels
+    /**
+     * Which access logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level access messages
+     */
+    static const websocketpp::log::level alog_level =
+        websocketpp::log::alevel::all;
+
+    ///
+    static const size_t connection_read_buffer_size = 16384;
+
+    /// Drop connections immediately on protocol error.
+    /**
+     * Drop connections on protocol error rather than sending a close frame.
+     * Off by default. This may result in legit messages near the error being
+     * dropped as well. It may free up resources otherwise spent dealing with
+     * misbehaving clients.
+     */
+    static const bool drop_on_protocol_error = false;
+
+    /// Suppresses the return of detailed connection close information
+    /**
+     * Silence close suppresses the return of detailed connection close
+     * information during the closing handshake. This information is useful
+     * for debugging and presenting useful errors to end users but may be
+     * undesirable for security reasons in some production environments.
+     * Close reasons could be used by an attacker to confirm that the endpoint
+     * is out of resources or be used to identify the WebSocket implementation
+     * in use.
+     *
+     * Note: this will suppress *all* close codes, including those explicitly
+     * sent by local applications.
+     */
+    static const bool silent_close = false;
+
+    /// Default maximum message size
+    /**
+     * Default value for the processor's maximum message size. Maximum message size
+     * determines the point at which the library will fail a connection with the 
+     * message_too_big protocol error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.3.0
+     */
+    static const size_t max_message_size = 32000000;
+
+    /// Default maximum http body size
+    /**
+     * Default value for the http parser's maximum body size. Maximum body size
+     * determines the point at which the library will abort reading an HTTP
+     * connection with the 413/request entity too large error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.5.0
+     */
+    static const size_t max_http_body_size = 32000000;
+
+    /// Global flag for enabling/disabling extensions
+    static const bool enable_extensions = true;
+
+    /// Extension specific settings:
+
+    /// permessage_compress extension
+    struct permessage_deflate_config {
+        typedef type::request_type request_type;
+
+        /// If the remote endpoint requests that we reset the compression
+        /// context after each message should we honor the request?
+        static const bool allow_disabling_context_takeover = true;
+
+        /// If the remote endpoint requests that we reduce the size of the
+        /// LZ77 sliding window size this is the lowest value that will be
+        /// allowed. Values range from 8 to 15. A value of 8 means we will
+        /// allow any possible window size. A value of 15 means do not allow
+        /// negotiation of the window size (ie require the default).
+        static const uint8_t minimum_outgoing_window_bits = 8;
+    };
+
+    typedef websocketpp::extensions::permessage_deflate::disabled
+        <permessage_deflate_config> permessage_deflate_type;
+
+    /// Autonegotiate permessage-deflate
+    /**
+     * Automatically enables the permessage-deflate extension.
+     *
+     * For clients this results in a permessage-deflate extension request being
+     * sent with every request rather than requiring it to be requested manually
+     *
+     * For servers this results in accepting the first set of extension settings
+     * requested by the client that we understand being used. The alternative is
+     * requiring the extension to be manually negotiated in `validate`. With
+     * auto-negotiate on, you may still override the auto-negotiate manually if
+     * needed.
+     */
+    //static const bool autonegotiate_compression = false;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_CORE_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/debug_asio.hpp b/subprojects/websocketpp/websocketpp/config/debug_asio.hpp
new file mode 100644
index 000000000..a57c736ce
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/debug_asio.hpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_ASIO_TLS_DEBUG_HPP
+#define WEBSOCKETPP_CONFIG_ASIO_TLS_DEBUG_HPP
+
+#include <websocketpp/config/debug.hpp>
+#include <websocketpp/transport/asio/endpoint.hpp>
+#include <websocketpp/transport/asio/security/tls.hpp>
+
+// Pull in non-tls config
+#include <websocketpp/config/debug_asio_no_tls.hpp>
+
+// Define TLS config
+namespace websocketpp {
+namespace config {
+
+/// Client/Server debug config with asio transport and TLS enabled
+struct debug_asio_tls : public debug_core {
+    typedef debug_asio_tls type;
+    typedef debug_core base;
+
+    typedef base::concurrency_type concurrency_type;
+
+    typedef base::request_type request_type;
+    typedef base::response_type response_type;
+
+    typedef base::message_type message_type;
+    typedef base::con_msg_manager_type con_msg_manager_type;
+    typedef base::endpoint_msg_manager_type endpoint_msg_manager_type;
+
+    typedef base::alog_type alog_type;
+    typedef base::elog_type elog_type;
+
+    typedef base::rng_type rng_type;
+
+    struct transport_config : public base::transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::alog_type alog_type;
+        typedef type::elog_type elog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+        typedef websocketpp::transport::asio::tls_socket::endpoint socket_type;
+    };
+
+    typedef websocketpp::transport::asio::endpoint<transport_config>
+        transport_type;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_ASIO_TLS_DEBUG_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/debug_asio_no_tls.hpp b/subprojects/websocketpp/websocketpp/config/debug_asio_no_tls.hpp
new file mode 100644
index 000000000..b3dc83b49
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/debug_asio_no_tls.hpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_ASIO_DEBUG_HPP
+#define WEBSOCKETPP_CONFIG_ASIO_DEBUG_HPP
+
+#include <websocketpp/config/debug.hpp>
+#include <websocketpp/transport/asio/endpoint.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Client/Server debug config with asio transport and TLS disabled
+struct debug_asio : public debug_core {
+    typedef debug_asio type;
+    typedef debug_core base;
+
+    typedef base::concurrency_type concurrency_type;
+
+    typedef base::request_type request_type;
+    typedef base::response_type response_type;
+
+    typedef base::message_type message_type;
+    typedef base::con_msg_manager_type con_msg_manager_type;
+    typedef base::endpoint_msg_manager_type endpoint_msg_manager_type;
+
+    typedef base::alog_type alog_type;
+    typedef base::elog_type elog_type;
+
+    typedef base::rng_type rng_type;
+
+    struct transport_config : public base::transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::alog_type alog_type;
+        typedef type::elog_type elog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+        typedef websocketpp::transport::asio::basic_socket::endpoint
+            socket_type;
+    };
+
+    typedef websocketpp::transport::asio::endpoint<transport_config>
+        transport_type;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_ASIO_DEBUG_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/minimal_client.hpp b/subprojects/websocketpp/websocketpp/config/minimal_client.hpp
new file mode 100644
index 000000000..72528cdee
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/minimal_client.hpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_MINIMAL_CLIENT_HPP
+#define WEBSOCKETPP_CONFIG_MINIMAL_CLIENT_HPP
+
+#include <websocketpp/config/minimal_server.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Client config with minimal dependencies
+/**
+ * This config strips out as many dependencies as possible. It is suitable for
+ * use as a base class for custom configs that want to implement or choose their
+ * own policies for components that even the core config includes.
+ *
+ * NOTE: this config stubs out enough that it cannot be used directly. You must
+ * supply at least a transport policy and a cryptographically secure random 
+ * number generation policy for a config based on `minimal_client` to do 
+ * anything useful.
+ *
+ * Present dependency list for minimal_server config:
+ *
+ * C++98 STL:
+ * <algorithm>
+ * <map>
+ * <sstream>
+ * <string>
+ * <vector>
+ *
+ * C++11 STL or Boost
+ * <memory>
+ * <functional>
+ * <system_error>
+ *
+ * Operating System:
+ * <stdint.h> or <boost/cstdint.hpp>
+ * <netinet/in.h> or <winsock2.h> (for ntohl.. could potentially bundle this)
+ *
+ * @since 0.4.0-dev
+ */
+typedef minimal_server minimal_client;
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_MINIMAL_CLIENT_HPP
diff --git a/subprojects/websocketpp/websocketpp/config/minimal_server.hpp b/subprojects/websocketpp/websocketpp/config/minimal_server.hpp
new file mode 100644
index 000000000..dd1aedb9d
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/config/minimal_server.hpp
@@ -0,0 +1,312 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONFIG_MINIMAL_HPP
+#define WEBSOCKETPP_CONFIG_MINIMAL_HPP
+
+// Non-Policy common stuff
+#include <websocketpp/common/platforms.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/stdint.hpp>
+
+// Concurrency
+#include <websocketpp/concurrency/none.hpp>
+
+// Transport
+#include <websocketpp/transport/stub/endpoint.hpp>
+
+// HTTP
+#include <websocketpp/http/request.hpp>
+#include <websocketpp/http/response.hpp>
+
+// Messages
+#include <websocketpp/message_buffer/message.hpp>
+#include <websocketpp/message_buffer/alloc.hpp>
+
+// Loggers
+#include <websocketpp/logger/stub.hpp>
+
+// RNG
+#include <websocketpp/random/none.hpp>
+
+// User stub base classes
+#include <websocketpp/endpoint_base.hpp>
+#include <websocketpp/connection_base.hpp>
+
+// Extensions
+#include <websocketpp/extensions/permessage_deflate/disabled.hpp>
+
+namespace websocketpp {
+namespace config {
+
+/// Server config with minimal dependencies
+/**
+ * This config strips out as many dependencies as possible. It is suitable for
+ * use as a base class for custom configs that want to implement or choose their
+ * own policies for components that even the core config includes.
+ *
+ * NOTE: this config stubs out enough that it cannot be used directly. You must
+ * supply at least a transport policy for a config based on `minimal_server` to
+ * do anything useful.
+ *
+ * Present dependency list for minimal_server config:
+ *
+ * C++98 STL:
+ * <algorithm>
+ * <map>
+ * <sstream>
+ * <string>
+ * <vector>
+ *
+ * C++11 STL or Boost
+ * <memory>
+ * <functional>
+ * <system_error>
+ *
+ * Operating System:
+ * <stdint.h> or <boost/cstdint.hpp>
+ * <netinet/in.h> or <winsock2.h> (for ntohl.. could potentially bundle this)
+ *
+ * @since 0.4.0-dev
+ */
+struct minimal_server {
+    typedef minimal_server type;
+
+    // Concurrency policy
+    typedef websocketpp::concurrency::none concurrency_type;
+
+    // HTTP Parser Policies
+    typedef http::parser::request request_type;
+    typedef http::parser::response response_type;
+
+    // Message Policies
+    typedef message_buffer::message<message_buffer::alloc::con_msg_manager>
+        message_type;
+    typedef message_buffer::alloc::con_msg_manager<message_type>
+        con_msg_manager_type;
+    typedef message_buffer::alloc::endpoint_msg_manager<con_msg_manager_type>
+        endpoint_msg_manager_type;
+
+    /// Logging policies
+    typedef websocketpp::log::stub elog_type;
+    typedef websocketpp::log::stub alog_type;
+
+    /// RNG policies
+    typedef websocketpp::random::none::int_generator<uint32_t> rng_type;
+
+    /// Controls compile time enabling/disabling of thread syncronization
+    /// code Disabling can provide a minor performance improvement to single
+    /// threaded applications
+    static bool const enable_multithreading = true;
+
+    struct transport_config {
+        typedef type::concurrency_type concurrency_type;
+        typedef type::elog_type elog_type;
+        typedef type::alog_type alog_type;
+        typedef type::request_type request_type;
+        typedef type::response_type response_type;
+
+        /// Controls compile time enabling/disabling of thread syncronization
+        /// code Disabling can provide a minor performance improvement to single
+        /// threaded applications
+        static bool const enable_multithreading = true;
+
+        /// Default timer values (in ms)
+
+        /// Length of time to wait for socket pre-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use
+         */
+        static const long timeout_socket_pre_init = 5000;
+
+        /// Length of time to wait before a proxy handshake is aborted
+        static const long timeout_proxy = 5000;
+
+        /// Length of time to wait for socket post-initialization
+        /**
+         * Exactly what this includes depends on the socket policy in use.
+         * Often this means the TLS handshake
+         */
+        static const long timeout_socket_post_init = 5000;
+
+        /// Length of time to wait for dns resolution
+        static const long timeout_dns_resolve = 5000;
+
+        /// Length of time to wait for TCP connect
+        static const long timeout_connect = 5000;
+
+        /// Length of time to wait for socket shutdown
+        static const long timeout_socket_shutdown = 5000;
+    };
+
+    /// Transport Endpoint Component
+    typedef websocketpp::transport::stub::endpoint<transport_config>
+        transport_type;
+
+    /// User overridable Endpoint base class
+    typedef websocketpp::endpoint_base endpoint_base;
+    /// User overridable Connection base class
+    typedef websocketpp::connection_base connection_base;
+
+    /// Default timer values (in ms)
+
+    /// Length of time before an opening handshake is aborted
+    static const long timeout_open_handshake = 5000;
+    /// Length of time before a closing handshake is aborted
+    static const long timeout_close_handshake = 5000;
+    /// Length of time to wait for a pong after a ping
+    static const long timeout_pong = 5000;
+
+    /// WebSocket Protocol version to use as a client
+    /**
+     * What version of the WebSocket Protocol to use for outgoing client
+     * connections. Setting this to a value other than 13 (RFC6455) is not
+     * recommended.
+     */
+    static const int client_version = 13; // RFC6455
+
+    /// Default static error logging channels
+    /**
+     * Which error logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level errors
+     */
+    static const websocketpp::log::level elog_level =
+        websocketpp::log::elevel::none;
+
+    /// Default static access logging channels
+    /**
+     * Which access logging channels to enable at compile time. Channels not
+     * enabled here will be unable to be selected by programs using the library.
+     * This option gives an optimizing compiler the ability to remove entirely
+     * code to test whether or not to print out log messages on a certain
+     * channel
+     *
+     * Default is all except for development/debug level access messages
+     */
+    static const websocketpp::log::level alog_level =
+        websocketpp::log::alevel::none;
+
+    ///
+    static const size_t connection_read_buffer_size = 16384;
+
+    /// Drop connections immediately on protocol error.
+    /**
+     * Drop connections on protocol error rather than sending a close frame.
+     * Off by default. This may result in legit messages near the error being
+     * dropped as well. It may free up resources otherwise spent dealing with
+     * misbehaving clients.
+     */
+    static const bool drop_on_protocol_error = false;
+
+    /// Suppresses the return of detailed connection close information
+    /**
+     * Silence close suppresses the return of detailed connection close
+     * information during the closing handshake. This information is useful
+     * for debugging and presenting useful errors to end users but may be
+     * undesirable for security reasons in some production environments.
+     * Close reasons could be used by an attacker to confirm that the endpoint
+     * is out of resources or be used to identify the WebSocket implementation
+     * in use.
+     *
+     * Note: this will suppress *all* close codes, including those explicitly
+     * sent by local applications.
+     */
+    static const bool silent_close = false;
+
+    /// Default maximum message size
+    /**
+     * Default value for the processor's maximum message size. Maximum message size
+     * determines the point at which the library will fail a connection with the 
+     * message_too_big protocol error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.4.0-alpha1
+     */
+    static const size_t max_message_size = 32000000;
+
+    /// Default maximum http body size
+    /**
+     * Default value for the http parser's maximum body size. Maximum body size
+     * determines the point at which the library will abort reading an HTTP
+     * connection with the 413/request entity too large error.
+     *
+     * The default is 32MB
+     *
+     * @since 0.5.0
+     */
+    static const size_t max_http_body_size = 32000000;
+
+    /// Global flag for enabling/disabling extensions
+    static const bool enable_extensions = true;
+
+    /// Extension specific settings:
+
+    /// permessage_compress extension
+    struct permessage_deflate_config {
+        typedef core::request_type request_type;
+
+        /// If the remote endpoint requests that we reset the compression
+        /// context after each message should we honor the request?
+        static const bool allow_disabling_context_takeover = true;
+
+        /// If the remote endpoint requests that we reduce the size of the
+        /// LZ77 sliding window size this is the lowest value that will be
+        /// allowed. Values range from 8 to 15. A value of 8 means we will
+        /// allow any possible window size. A value of 15 means do not allow
+        /// negotiation of the window size (ie require the default).
+        static const uint8_t minimum_outgoing_window_bits = 8;
+    };
+
+    typedef websocketpp::extensions::permessage_deflate::disabled
+        <permessage_deflate_config> permessage_deflate_type;
+
+    /// Autonegotiate permessage-deflate
+    /**
+     * Automatically enables the permessage-deflate extension.
+     *
+     * For clients this results in a permessage-deflate extension request being
+     * sent with every request rather than requiring it to be requested manually
+     *
+     * For servers this results in accepting the first set of extension settings
+     * requested by the client that we understand being used. The alternative is
+     * requiring the extension to be manually negotiated in `validate`. With
+     * auto-negotiate on, you may still override the auto-negotiate manually if
+     * needed.
+     */
+    //static const bool autonegotiate_compression = false;
+};
+
+} // namespace config
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONFIG_MINIMAL_HPP
diff --git a/subprojects/websocketpp/websocketpp/connection.hpp b/subprojects/websocketpp/websocketpp/connection.hpp
new file mode 100644
index 000000000..d019fce33
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/connection.hpp
@@ -0,0 +1,1642 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONNECTION_HPP
+#define WEBSOCKETPP_CONNECTION_HPP
+
+#include <websocketpp/close.hpp>
+#include <websocketpp/error.hpp>
+#include <websocketpp/frame.hpp>
+
+#include <websocketpp/logger/levels.hpp>
+#include <websocketpp/processors/processor.hpp>
+#include <websocketpp/transport/base/connection.hpp>
+#include <websocketpp/http/constants.hpp>
+
+#include <websocketpp/common/connection_hdl.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/functional.hpp>
+
+#include <queue>
+#include <sstream>
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+
+/// The type and function signature of an open handler
+/**
+ * The open handler is called once for every successful WebSocket connection
+ * attempt. Either the fail handler or the open handler will be called for each
+ * WebSocket connection attempt. HTTP Connections that did not attempt to
+ * upgrade the connection to the WebSocket protocol will trigger the http
+ * handler instead of fail/open.
+ */
+typedef lib::function<void(connection_hdl)> open_handler;
+
+/// The type and function signature of a close handler
+/**
+ * The close handler is called once for every successfully established
+ * connection after it is no longer capable of sending or receiving new messages
+ *
+ * The close handler will be called exactly once for every connection for which
+ * the open handler was called.
+ */
+typedef lib::function<void(connection_hdl)> close_handler;
+
+/// The type and function signature of a fail handler
+/**
+ * The fail handler is called once for every unsuccessful WebSocket connection
+ * attempt. Either the fail handler or the open handler will be called for each
+ * WebSocket connection attempt. HTTP Connections that did not attempt to
+ * upgrade the connection to the WebSocket protocol will trigger the http
+ * handler instead of fail/open.
+ */
+typedef lib::function<void(connection_hdl)> fail_handler;
+
+/// The type and function signature of an interrupt handler
+/**
+ * The interrupt handler is called when a connection receives an interrupt
+ * request from the application. Interrupts allow the application to trigger a
+ * handler to be run in the absense of a WebSocket level handler trigger (like
+ * a new message).
+ *
+ * This is typically used by another application thread to schedule some tasks
+ * that can only be run from within the handler chain for thread safety reasons.
+ */
+typedef lib::function<void(connection_hdl)> interrupt_handler;
+
+/// The type and function signature of a ping handler
+/**
+ * The ping handler is called when the connection receives a WebSocket ping
+ * control frame. The string argument contains the ping payload. The payload is
+ * a binary string up to 126 bytes in length. The ping handler returns a bool,
+ * true if a pong response should be sent, false if the pong response should be
+ * suppressed.
+ */
+typedef lib::function<bool(connection_hdl,std::string)> ping_handler;
+
+/// The type and function signature of a pong handler
+/**
+ * The pong handler is called when the connection receives a WebSocket pong
+ * control frame. The string argument contains the pong payload. The payload is
+ * a binary string up to 126 bytes in length.
+ */
+typedef lib::function<void(connection_hdl,std::string)> pong_handler;
+
+/// The type and function signature of a pong timeout handler
+/**
+ * The pong timeout handler is called when a ping goes unanswered by a pong for
+ * longer than the locally specified timeout period.
+ */
+typedef lib::function<void(connection_hdl,std::string)> pong_timeout_handler;
+
+/// The type and function signature of a validate handler
+/**
+ * The validate handler is called after a WebSocket handshake has been received
+ * and processed but before it has been accepted. This gives the application a
+ * chance to implement connection details specific policies for accepting
+ * connections and the ability to negotiate extensions and subprotocols.
+ *
+ * The validate handler return value indicates whether or not the connection
+ * should be accepted. Additional methods may be called during the function to
+ * set response headers, set HTTP return/error codes, etc.
+ */
+typedef lib::function<bool(connection_hdl)> validate_handler;
+
+/// The type and function signature of a http handler
+/**
+ * The http handler is called when an HTTP connection is made that does not
+ * attempt to upgrade the connection to the WebSocket protocol. This allows
+ * WebSocket++ servers to respond to these requests with regular HTTP responses.
+ *
+ * This can be used to deliver error pages & dashboards and to deliver static
+ * files such as the base HTML & JavaScript for an otherwise single page
+ * WebSocket application.
+ *
+ * Note: WebSocket++ is designed to be a high performance WebSocket server. It
+ * is not tuned to provide a full featured, high performance, HTTP web server
+ * solution. The HTTP handler is appropriate only for low volume HTTP traffic.
+ * If you expect to serve high volumes of HTTP traffic a dedicated HTTP web
+ * server is strongly recommended.
+ *
+ * The default HTTP handler will return a 426 Upgrade Required error. Custom
+ * handlers may override the response status code to deliver any type of
+ * response.
+ */
+typedef lib::function<void(connection_hdl)> http_handler;
+
+//
+typedef lib::function<void(lib::error_code const & ec, size_t bytes_transferred)> read_handler;
+typedef lib::function<void(lib::error_code const & ec)> write_frame_handler;
+
+// constants related to the default WebSocket protocol versions available
+#ifdef _WEBSOCKETPP_INITIALIZER_LISTS_ // simplified C++11 version
+    /// Container that stores the list of protocol versions supported
+    /**
+     * @todo Move this to configs to allow compile/runtime disabling or enabling
+     * of protocol versions
+     */
+    static std::vector<int> const versions_supported = {0,7,8,13};
+#else
+    /// Helper array to get around lack of initializer lists pre C++11
+    static int const helper[] = {0,7,8,13};
+    /// Container that stores the list of protocol versions supported
+    /**
+     * @todo Move this to configs to allow compile/runtime disabling or enabling
+     * of protocol versions
+     */
+    static std::vector<int> const versions_supported(helper,helper+4);
+#endif
+
+namespace session {
+namespace state {
+    // externally visible session state (states based on the RFC)
+    enum value {
+        connecting = 0,
+        open = 1,
+        closing = 2,
+        closed = 3
+    };
+} // namespace state
+
+
+namespace fail {
+namespace status {
+    enum value {
+        GOOD = 0,           // no failure yet!
+        SYSTEM = 1,         // system call returned error, check that code
+        WEBSOCKET = 2,      // websocket close codes contain error
+        UNKNOWN = 3,        // No failure information is available
+        TIMEOUT_TLS = 4,    // TLS handshake timed out
+        TIMEOUT_WS = 5      // WS handshake timed out
+    };
+} // namespace status
+} // namespace fail
+
+namespace internal_state {
+    // More granular internal states. These are used for multi-threaded
+    // connection synchronization and preventing values that are not yet or no
+    // longer available from being used.
+
+    enum value {
+        USER_INIT = 0,
+        TRANSPORT_INIT = 1,
+        READ_HTTP_REQUEST = 2,
+        WRITE_HTTP_REQUEST = 3,
+        READ_HTTP_RESPONSE = 4,
+        WRITE_HTTP_RESPONSE = 5,
+        PROCESS_HTTP_REQUEST = 6,
+        PROCESS_CONNECTION = 7
+    };
+} // namespace internal_state
+
+
+namespace http_state {
+    // states to keep track of the progress of http connections
+
+    enum value {
+        init = 0,
+        deferred = 1,
+        headers_written = 2,
+        body_written = 3,
+        closed = 4
+    };
+} // namespace http_state
+
+} // namespace session
+
+/// Represents an individual WebSocket connection
+template <typename config>
+class connection
+ : public config::transport_type::transport_con_type
+ , public config::connection_base
+{
+public:
+    /// Type of this connection
+    typedef connection<config> type;
+    /// Type of a shared pointer to this connection
+    typedef lib::shared_ptr<type> ptr;
+    /// Type of a weak pointer to this connection
+    typedef lib::weak_ptr<type> weak_ptr;
+
+    /// Type of the concurrency component of this connection
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of the access logging policy
+    typedef typename config::alog_type alog_type;
+    /// Type of the error logging policy
+    typedef typename config::elog_type elog_type;
+
+    /// Type of the transport component of this connection
+    typedef typename config::transport_type::transport_con_type
+        transport_con_type;
+    /// Type of a shared pointer to the transport component of this connection
+    typedef typename transport_con_type::ptr transport_con_ptr;
+
+    typedef lib::function<void(ptr)> termination_handler;
+
+    typedef typename concurrency_type::scoped_lock_type scoped_lock_type;
+    typedef typename concurrency_type::mutex_type mutex_type;
+
+    typedef typename config::request_type request_type;
+    typedef typename config::response_type response_type;
+
+    typedef typename config::message_type message_type;
+    typedef typename message_type::ptr message_ptr;
+
+    typedef typename config::con_msg_manager_type con_msg_manager_type;
+    typedef typename con_msg_manager_type::ptr con_msg_manager_ptr;
+
+    /// Type of RNG
+    typedef typename config::rng_type rng_type;
+
+    typedef processor::processor<config> processor_type;
+    typedef lib::shared_ptr<processor_type> processor_ptr;
+
+    // Message handler (needs to know message type)
+    typedef lib::function<void(connection_hdl,message_ptr)> message_handler;
+
+    /// Type of a pointer to a transport timer handle
+    typedef typename transport_con_type::timer_ptr timer_ptr;
+
+    // Misc Convenience Types
+    typedef session::internal_state::value istate_type;
+
+private:
+    enum terminate_status {
+        failed = 1,
+        closed,
+        unknown
+    };
+public:
+
+    explicit connection(bool p_is_server, std::string const & ua, const lib::shared_ptr<alog_type>& alog,
+                        const lib::shared_ptr<elog_type>& elog, rng_type & rng)
+      : transport_con_type(p_is_server, alog, elog)
+      , m_handle_read_frame(lib::bind(
+            &type::handle_read_frame,
+            this,
+            lib::placeholders::_1,
+            lib::placeholders::_2
+        ))
+      , m_write_frame_handler(lib::bind(
+            &type::handle_write_frame,
+            this,
+            lib::placeholders::_1
+        ))
+      , m_user_agent(ua)
+      , m_open_handshake_timeout_dur(config::timeout_open_handshake)
+      , m_close_handshake_timeout_dur(config::timeout_close_handshake)
+      , m_pong_timeout_dur(config::timeout_pong)
+      , m_max_message_size(config::max_message_size)
+      , m_state(session::state::connecting)
+      , m_internal_state(session::internal_state::USER_INIT)
+      , m_msg_manager(new con_msg_manager_type())
+      , m_send_buffer_size(0)
+      , m_write_flag(false)
+      , m_read_flag(true)
+      , m_is_server(p_is_server)
+      , m_alog(alog)
+      , m_elog(elog)
+      , m_rng(rng)
+      , m_local_close_code(close::status::abnormal_close)
+      , m_remote_close_code(close::status::abnormal_close)
+      , m_is_http(false)
+      , m_http_state(session::http_state::init)
+      , m_was_clean(false)
+    {
+        m_alog->write(log::alevel::devel,"connection constructor");
+    }
+
+    /// Get a shared pointer to this component
+    ptr get_shared() {
+        return lib::static_pointer_cast<type>(transport_con_type::get_shared());
+    }
+
+    ///////////////////////////
+    // Set Handler Callbacks //
+    ///////////////////////////
+
+    /// Set open handler
+    /**
+     * The open handler is called after the WebSocket handshake is complete and
+     * the connection is considered OPEN.
+     *
+     * @param h The new open_handler
+     */
+    void set_open_handler(open_handler h) {
+        m_open_handler = h;
+    }
+
+    /// Set close handler
+    /**
+     * The close handler is called immediately after the connection is closed.
+     *
+     * @param h The new close_handler
+     */
+    void set_close_handler(close_handler h) {
+        m_close_handler = h;
+    }
+
+    /// Set fail handler
+    /**
+     * The fail handler is called whenever the connection fails while the
+     * handshake is bring processed.
+     *
+     * @param h The new fail_handler
+     */
+    void set_fail_handler(fail_handler h) {
+        m_fail_handler = h;
+    }
+
+    /// Set ping handler
+    /**
+     * The ping handler is called whenever the connection receives a ping
+     * control frame. The ping payload is included.
+     *
+     * The ping handler's return time controls whether or not a pong is
+     * sent in response to this ping. Returning false will suppress the
+     * return pong. If no ping handler is set a pong will be sent.
+     *
+     * @param h The new ping_handler
+     */
+    void set_ping_handler(ping_handler h) {
+        m_ping_handler = h;
+    }
+
+    /// Set pong handler
+    /**
+     * The pong handler is called whenever the connection receives a pong
+     * control frame. The pong payload is included.
+     *
+     * @param h The new pong_handler
+     */
+    void set_pong_handler(pong_handler h) {
+        m_pong_handler = h;
+    }
+
+    /// Set pong timeout handler
+    /**
+     * If the transport component being used supports timers, the pong timeout
+     * handler is called whenever a pong control frame is not received with the
+     * configured timeout period after the application sends a ping.
+     *
+     * The config setting `timeout_pong` controls the length of the timeout
+     * period. It is specified in milliseconds.
+     *
+     * This can be used to probe the health of the remote endpoint's WebSocket
+     * implementation. This does not guarantee that the remote application
+     * itself is still healthy but can be a useful diagnostic.
+     *
+     * Note: receipt of this callback doesn't mean the pong will never come.
+     * This functionality will not suppress delivery of the pong in question
+     * should it arrive after the timeout.
+     *
+     * @param h The new pong_timeout_handler
+     */
+    void set_pong_timeout_handler(pong_timeout_handler h) {
+        m_pong_timeout_handler = h;
+    }
+
+    /// Set interrupt handler
+    /**
+     * The interrupt handler is called whenever the connection is manually
+     * interrupted by the application.
+     *
+     * @param h The new interrupt_handler
+     */
+    void set_interrupt_handler(interrupt_handler h) {
+        m_interrupt_handler = h;
+    }
+
+    /// Set http handler
+    /**
+     * The http handler is called after an HTTP request other than a WebSocket
+     * upgrade request is received. It allows a WebSocket++ server to respond
+     * to regular HTTP requests on the same port as it processes WebSocket
+     * connections. This can be useful for hosting error messages, flash
+     * policy files, status pages, and other simple HTTP responses. It is not
+     * intended to be used as a primary web server.
+     *
+     * @param h The new http_handler
+     */
+    void set_http_handler(http_handler h) {
+        m_http_handler = h;
+    }
+
+    /// Set validate handler
+    /**
+     * The validate handler is called after a WebSocket handshake has been
+     * parsed but before a response is returned. It provides the application
+     * a chance to examine the request and determine whether or not it wants
+     * to accept the connection.
+     *
+     * Returning false from the validate handler will reject the connection.
+     * If no validate handler is present, all connections will be allowed.
+     *
+     * @param h The new validate_handler
+     */
+    void set_validate_handler(validate_handler h) {
+        m_validate_handler = h;
+    }
+
+    /// Set message handler
+    /**
+     * The message handler is called after a new message has been received.
+     *
+     * @param h The new message_handler
+     */
+    void set_message_handler(message_handler h) {
+        m_message_handler = h;
+    }
+
+    //////////////////////////////////////////
+    // Connection timeouts and other limits //
+    //////////////////////////////////////////
+
+    /// Set open handshake timeout
+    /**
+     * Sets the length of time the library will wait after an opening handshake
+     * has been initiated before cancelling it. This can be used to prevent
+     * excessive wait times for outgoing clients or excessive resource usage
+     * from broken clients or DoS attacks on servers.
+     *
+     * Connections that time out will have their fail handlers called with the
+     * open_handshake_timeout error code.
+     *
+     * The default value is specified via the compile time config value
+     * 'timeout_open_handshake'. The default value in the core config
+     * is 5000ms. A value of 0 will disable the timer entirely.
+     *
+     * To be effective, the transport you are using must support timers. See
+     * the documentation for your transport policy for details about its
+     * timer support.
+     *
+     * @param dur The length of the open handshake timeout in ms
+     */
+    void set_open_handshake_timeout(long dur) {
+        m_open_handshake_timeout_dur = dur;
+    }
+
+    /// Set close handshake timeout
+    /**
+     * Sets the length of time the library will wait after a closing handshake
+     * has been initiated before cancelling it. This can be used to prevent
+     * excessive wait times for outgoing clients or excessive resource usage
+     * from broken clients or DoS attacks on servers.
+     *
+     * Connections that time out will have their close handlers called with the
+     * close_handshake_timeout error code.
+     *
+     * The default value is specified via the compile time config value
+     * 'timeout_close_handshake'. The default value in the core config
+     * is 5000ms. A value of 0 will disable the timer entirely.
+     *
+     * To be effective, the transport you are using must support timers. See
+     * the documentation for your transport policy for details about its
+     * timer support.
+     *
+     * @param dur The length of the close handshake timeout in ms
+     */
+    void set_close_handshake_timeout(long dur) {
+        m_close_handshake_timeout_dur = dur;
+    }
+
+    /// Set pong timeout
+    /**
+     * Sets the length of time the library will wait for a pong response to a
+     * ping. This can be used as a keepalive or to detect broken  connections.
+     *
+     * Pong responses that time out will have the pong timeout handler called.
+     *
+     * The default value is specified via the compile time config value
+     * 'timeout_pong'. The default value in the core config
+     * is 5000ms. A value of 0 will disable the timer entirely.
+     *
+     * To be effective, the transport you are using must support timers. See
+     * the documentation for your transport policy for details about its
+     * timer support.
+     *
+     * @param dur The length of the pong timeout in ms
+     */
+    void set_pong_timeout(long dur) {
+        m_pong_timeout_dur = dur;
+    }
+
+    /// Get maximum message size
+    /**
+     * Get maximum message size. Maximum message size determines the point at 
+     * which the connection will fail with the message_too_big protocol error.
+     *
+     * The default is set by the endpoint that creates the connection.
+     *
+     * @since 0.3.0
+     */
+    size_t get_max_message_size() const {
+        return m_max_message_size;
+    }
+    
+    /// Set maximum message size
+    /**
+     * Set maximum message size. Maximum message size determines the point at 
+     * which the connection will fail with the message_too_big protocol error. 
+     * This value may be changed during the connection.
+     *
+     * The default is set by the endpoint that creates the connection.
+     *
+     * @since 0.3.0
+     *
+     * @param new_value The value to set as the maximum message size.
+     */
+    void set_max_message_size(size_t new_value) {
+        m_max_message_size = new_value;
+        if (m_processor) {
+            m_processor->set_max_message_size(new_value);
+        }
+    }
+    
+    /// Get maximum HTTP message body size
+    /**
+     * Get maximum HTTP message body size. Maximum message body size determines
+     * the point at which the connection will stop reading an HTTP request whose
+     * body is too large.
+     *
+     * The default is set by the endpoint that creates the connection.
+     *
+     * @since 0.5.0
+     *
+     * @return The maximum HTTP message body size
+     */
+    size_t get_max_http_body_size() const {
+        return m_request.get_max_body_size();
+    }
+    
+    /// Set maximum HTTP message body size
+    /**
+     * Set maximum HTTP message body size. Maximum message body size determines
+     * the point at which the connection will stop reading an HTTP request whose
+     * body is too large.
+     *
+     * The default is set by the endpoint that creates the connection.
+     *
+     * @since 0.5.0
+     *
+     * @param new_value The value to set as the maximum message size.
+     */
+    void set_max_http_body_size(size_t new_value) {
+        m_request.set_max_body_size(new_value);
+    }
+
+    //////////////////////////////////
+    // Uncategorized public methods //
+    //////////////////////////////////
+
+    /// Get the size of the outgoing write buffer (in payload bytes)
+    /**
+     * Retrieves the number of bytes in the outgoing write buffer that have not
+     * already been dispatched to the transport layer. This represents the bytes
+     * that are presently cancelable without uncleanly ending the websocket
+     * connection
+     *
+     * This method invokes the m_write_lock mutex
+     *
+     * @return The current number of bytes in the outgoing send buffer.
+     */
+    size_t get_buffered_amount() const;
+
+    /// Get the size of the outgoing write buffer (in payload bytes)
+    /**
+     * @deprecated use `get_buffered_amount` instead
+     */
+    size_t buffered_amount() const {
+        return get_buffered_amount();
+    }
+
+    ////////////////////
+    // Action Methods //
+    ////////////////////
+
+    /// Create a message and then add it to the outgoing send queue
+    /**
+     * Convenience method to send a message given a payload string and
+     * optionally an opcode. Default opcode is utf8 text.
+     *
+     * This method locks the m_write_lock mutex
+     *
+     * @param payload The payload string to generated the message with
+     *
+     * @param op The opcode to generated the message with. Default is
+     * frame::opcode::text
+     */
+    lib::error_code send(std::string const & payload, frame::opcode::value op =
+        frame::opcode::text);
+
+    /// Send a message (raw array overload)
+    /**
+     * Convenience method to send a message given a raw array and optionally an
+     * opcode. Default opcode is binary.
+     *
+     * This method locks the m_write_lock mutex
+     *
+     * @param payload A pointer to the array containing the bytes to send.
+     *
+     * @param len Length of the array.
+     *
+     * @param op The opcode to generated the message with. Default is
+     * frame::opcode::binary
+     */
+    lib::error_code send(void const * payload, size_t len, frame::opcode::value
+        op = frame::opcode::binary);
+
+    /// Add a message to the outgoing send queue
+    /**
+     * If presented with a prepared message it is added without validation or
+     * framing. If presented with an unprepared message it is validated, framed,
+     * and then added
+     *
+     * Errors are returned via an exception
+     * \todo make exception system_error rather than error_code
+     *
+     * This method invokes the m_write_lock mutex
+     *
+     * @param msg A message_ptr to the message to send.
+     */
+    lib::error_code send(message_ptr msg);
+
+    /// Asyncronously invoke handler::on_inturrupt
+    /**
+     * Signals to the connection to asyncronously invoke the on_inturrupt
+     * callback for this connection's handler once it is safe to do so.
+     *
+     * When the on_inturrupt handler callback is called it will be from
+     * within the transport event loop with all the thread safety features
+     * guaranteed by the transport to regular handlers
+     *
+     * Multiple inturrupt signals can be active at once on the same connection
+     *
+     * @return An error code
+     */
+    lib::error_code interrupt();
+    
+    /// Transport inturrupt callback
+    void handle_interrupt();
+    
+    /// Pause reading of new data
+    /**
+     * Signals to the connection to halt reading of new data. While reading is paused, 
+     * the connection will stop reading from its associated socket. In turn this will 
+     * result in TCP based flow control kicking in and slowing data flow from the remote
+     * endpoint.
+     *
+     * This is useful for applications that push new requests to a queue to be processed
+     * by another thread and need a way to signal when their request queue is full without
+     * blocking the network processing thread.
+     *
+     * Use `resume_reading()` to resume.
+     *
+     * If supported by the transport this is done asynchronously. As such reading may not
+     * stop until the current read operation completes. Typically you can expect to
+     * receive no more bytes after initiating a read pause than the size of the read 
+     * buffer.
+     *
+     * If reading is paused for this connection already nothing is changed.
+     */
+    lib::error_code pause_reading();
+
+    /// Pause reading callback
+    void handle_pause_reading();
+
+    /// Resume reading of new data
+    /**
+     * Signals to the connection to resume reading of new data after it was paused by
+     * `pause_reading()`.
+     *
+     * If reading is not paused for this connection already nothing is changed.
+     */
+    lib::error_code resume_reading();
+
+    /// Resume reading callback
+    void handle_resume_reading();
+
+    /// Send a ping
+    /**
+     * Initiates a ping with the given payload/
+     *
+     * There is no feedback directly from ping except in cases of immediately
+     * detectable errors. Feedback will be provided via on_pong or
+     * on_pong_timeout callbacks.
+     *
+     * Ping locks the m_write_lock mutex
+     *
+     * @param payload Payload to be used for the ping
+     */
+    void ping(std::string const & payload);
+
+    /// exception free variant of ping
+    void ping(std::string const & payload, lib::error_code & ec);
+
+    /// Utility method that gets called back when the ping timer expires
+    void handle_pong_timeout(std::string payload, lib::error_code const & ec);
+
+    /// Send a pong
+    /**
+     * Initiates a pong with the given payload.
+     *
+     * There is no feedback from a pong once sent.
+     *
+     * Pong locks the m_write_lock mutex
+     *
+     * @param payload Payload to be used for the pong
+     */
+    void pong(std::string const & payload);
+
+    /// exception free variant of pong
+    void pong(std::string const & payload, lib::error_code & ec);
+
+    /// Close the connection
+    /**
+     * Initiates the close handshake process.
+     *
+     * If close returns successfully the connection will be in the closing
+     * state and no additional messages may be sent. All messages sent prior
+     * to calling close will be written out before the connection is closed.
+     *
+     * If no reason is specified none will be sent. If no code is specified
+     * then no code will be sent.
+     *
+     * The handler's on_close callback will be called once the close handshake
+     * is complete.
+     *
+     * Reasons will be automatically truncated to the maximum length (123 bytes)
+     * if necessary.
+     *
+     * @param code The close code to send
+     * @param reason The close reason to send
+     */
+    void close(close::status::value const code, std::string const & reason);
+
+    /// exception free variant of close
+    void close(close::status::value const code, std::string const & reason,
+        lib::error_code & ec);
+
+    ////////////////////////////////////////////////
+    // Pass-through access to the uri information //
+    ////////////////////////////////////////////////
+
+    /// Returns the secure flag from the connection URI
+    /**
+     * This value is available after the HTTP request has been fully read and
+     * may be called from any thread.
+     *
+     * @return Whether or not the connection URI is flagged secure.
+     */
+    bool get_secure() const;
+
+    /// Returns the host component of the connection URI
+    /**
+     * This value is available after the HTTP request has been fully read and
+     * may be called from any thread.
+     *
+     * @return The host component of the connection URI
+     */
+    std::string const & get_host() const;
+
+    /// Returns the resource component of the connection URI
+    /**
+     * This value is available after the HTTP request has been fully read and
+     * may be called from any thread.
+     *
+     * @return The resource component of the connection URI
+     */
+    std::string const & get_resource() const;
+
+    /// Returns the port component of the connection URI
+    /**
+     * This value is available after the HTTP request has been fully read and
+     * may be called from any thread.
+     *
+     * @return The port component of the connection URI
+     */
+    uint16_t get_port() const;
+
+    /// Gets the connection URI
+    /**
+     * This should really only be called by internal library methods unless you
+     * really know what you are doing.
+     *
+     * @return A pointer to the connection's URI
+     */
+    uri_ptr get_uri() const;
+
+    /// Sets the connection URI
+    /**
+     * This should really only be called by internal library methods unless you
+     * really know what you are doing.
+     *
+     * @param uri The new URI to set
+     */
+    void set_uri(uri_ptr uri);
+
+    /////////////////////////////
+    // Subprotocol negotiation //
+    /////////////////////////////
+
+    /// Gets the negotated subprotocol
+    /**
+     * Retrieves the subprotocol that was negotiated during the handshake. This
+     * method is valid in the open handler and later.
+     *
+     * @return The negotiated subprotocol
+     */
+    std::string const & get_subprotocol() const;
+
+    /// Gets all of the subprotocols requested by the client
+    /**
+     * Retrieves the subprotocols that were requested during the handshake. This
+     * method is valid in the validate handler and later.
+     *
+     * @return A vector of the requested subprotocol
+     */
+    std::vector<std::string> const & get_requested_subprotocols() const;
+
+    /// Adds the given subprotocol string to the request list (exception free)
+    /**
+     * Adds a subprotocol to the list to send with the opening handshake. This
+     * may be called multiple times to request more than one. If the server
+     * supports one of these, it may choose one. If so, it will return it
+     * in it's handshake reponse and the value will be available via
+     * get_subprotocol(). Subprotocol requests should be added in order of
+     * preference.
+     *
+     * @param request The subprotocol to request
+     * @param ec A reference to an error code that will be filled in the case of
+     * errors
+     */
+    void add_subprotocol(std::string const & request, lib::error_code & ec);
+
+    /// Adds the given subprotocol string to the request list
+    /**
+     * Adds a subprotocol to the list to send with the opening handshake. This
+     * may be called multiple times to request more than one. If the server
+     * supports one of these, it may choose one. If so, it will return it
+     * in it's handshake reponse and the value will be available via
+     * get_subprotocol(). Subprotocol requests should be added in order of
+     * preference.
+     *
+     * @param request The subprotocol to request
+     */
+    void add_subprotocol(std::string const & request);
+
+    /// Select a subprotocol to use (exception free)
+    /**
+     * Indicates which subprotocol should be used for this connection. Valid
+     * only during the validate handler callback. Subprotocol selected must have
+     * been requested by the client. Consult get_requested_subprotocols() for a
+     * list of valid subprotocols.
+     *
+     * This member function is valid on server endpoints/connections only
+     *
+     * @param value The subprotocol to select
+     * @param ec A reference to an error code that will be filled in the case of
+     * errors
+     */
+    void select_subprotocol(std::string const & value, lib::error_code & ec);
+
+    /// Select a subprotocol to use
+    /**
+     * Indicates which subprotocol should be used for this connection. Valid
+     * only during the validate handler callback. Subprotocol selected must have
+     * been requested by the client. Consult get_requested_subprotocols() for a
+     * list of valid subprotocols.
+     *
+     * This member function is valid on server endpoints/connections only
+     *
+     * @param value The subprotocol to select
+     */
+    void select_subprotocol(std::string const & value);
+
+    /////////////////////////////////////////////////////////////
+    // Pass-through access to the request and response objects //
+    /////////////////////////////////////////////////////////////
+
+    /// Retrieve a request header
+    /**
+     * Retrieve the value of a header from the handshake HTTP request.
+     *
+     * @param key Name of the header to get
+     * @return The value of the header
+     */
+    std::string const & get_request_header(std::string const & key) const;
+
+    /// Retrieve a request body
+    /**
+     * Retrieve the value of the request body. This value is typically used with
+     * PUT and POST requests to upload files or other data. Only HTTP
+     * connections will ever have bodies. WebSocket connection's will always
+     * have blank bodies.
+     *
+     * @return The value of the request body.
+     */
+    std::string const & get_request_body() const;
+
+    /// Retrieve a response header
+    /**
+     * Retrieve the value of a header from the handshake HTTP request.
+     *
+     * @param key Name of the header to get
+     * @return The value of the header
+     */
+    std::string const & get_response_header(std::string const & key) const;
+
+    /// Get response HTTP status code
+    /**
+     * Gets the response status code 
+     *
+     * @since 0.7.0
+     *
+     * @return The response status code sent
+     */
+    http::status_code::value get_response_code() const {
+        return m_response.get_status_code();
+    }
+
+    /// Get response HTTP status message
+    /**
+     * Gets the response status message 
+     *
+     * @since 0.7.0
+     *
+     * @return The response status message sent
+     */
+    std::string const & get_response_msg() const {
+        return m_response.get_status_msg();
+    }
+    
+    /// Set response status code and message
+    /**
+     * Sets the response status code to `code` and looks up the corresponding
+     * message for standard codes. Non-standard codes will be entered as Unknown
+     * use set_status(status_code::value,std::string) overload to set both
+     * values explicitly.
+     *
+     * This member function is valid only from the http() and validate() handler
+     * callbacks.
+     *
+     * @param code Code to set
+     * @param msg Message to set
+     * @see websocketpp::http::response::set_status
+     */
+    void set_status(http::status_code::value code);
+
+    /// Set response status code and message
+    /**
+     * Sets the response status code and message to independent custom values.
+     * use set_status(status_code::value) to set the code and have the standard
+     * message be automatically set.
+     *
+     * This member function is valid only from the http() and validate() handler
+     * callbacks.
+     *
+     * @param code Code to set
+     * @param msg Message to set
+     * @see websocketpp::http::response::set_status
+     */
+    void set_status(http::status_code::value code, std::string const & msg);
+
+    /// Set response body content
+    /**
+     * Set the body content of the HTTP response to the parameter string. Note
+     * set_body will also set the Content-Length HTTP header to the appropriate
+     * value. If you want the Content-Length header to be something else set it
+     * to something else after calling set_body
+     *
+     * This member function is valid only from the http() and validate() handler
+     * callbacks.
+     *
+     * @param value String data to include as the body content.
+     * @see websocketpp::http::response::set_body
+     */
+    void set_body(std::string const & value);
+
+    /// Append a header
+    /**
+     * If a header with this name already exists the value will be appended to
+     * the existing header to form a comma separated list of values. Use
+     * `connection::replace_header` to overwrite existing values.
+     *
+     * This member function is valid only from the http() and validate() handler
+     * callbacks, or to a client connection before connect has been called.
+     *
+     * @param key Name of the header to set
+     * @param val Value to add
+     * @see replace_header
+     * @see websocketpp::http::parser::append_header
+     */
+    void append_header(std::string const & key, std::string const & val);
+
+    /// Replace a header
+    /**
+     * If a header with this name already exists the old value will be replaced
+     * Use `connection::append_header` to append to a list of existing values.
+     *
+     * This member function is valid only from the http() and validate() handler
+     * callbacks, or to a client connection before connect has been called.
+     *
+     * @param key Name of the header to set
+     * @param val Value to set
+     * @see append_header
+     * @see websocketpp::http::parser::replace_header
+     */
+    void replace_header(std::string const & key, std::string const & val);
+
+    /// Remove a header
+    /**
+     * Removes a header from the response.
+     *
+     * This member function is valid only from the http() and validate() handler
+     * callbacks, or to a client connection before connect has been called.
+     *
+     * @param key The name of the header to remove
+     * @see websocketpp::http::parser::remove_header
+     */
+    void remove_header(std::string const & key);
+
+    /// Get request object
+    /**
+     * Direct access to request object. This can be used to call methods of the
+     * request object that are not part of the standard request API that
+     * connection wraps.
+     *
+     * Note use of this method involves using behavior specific to the
+     * configured HTTP policy. Such behavior may not work with alternate HTTP
+     * policies.
+     *
+     * @since 0.3.0-alpha3
+     *
+     * @return A const reference to the raw request object
+     */
+    request_type const & get_request() const {
+        return m_request;
+    }
+    
+    /// Get response object
+    /**
+     * Direct access to the HTTP response sent or received as a part of the
+     * opening handshake. This can be used to call methods of the response
+     * object that are not part of the standard request API that connection
+     * wraps.
+     *
+     * Note use of this method involves using behavior specific to the
+     * configured HTTP policy. Such behavior may not work with alternate HTTP
+     * policies.
+     *
+     * @since 0.7.0
+     *
+     * @return A const reference to the raw response object
+     */
+    response_type const & get_response() const {
+        return m_response;
+    }
+    
+    /// Defer HTTP Response until later (Exception free)
+    /**
+     * Used in the http handler to defer the HTTP response for this connection
+     * until later. Handshake timers will be canceled and the connection will be
+     * left open until `send_http_response` or an equivalent is called.
+     *
+     * Warning: deferred connections won't time out and as a result can tie up
+     * resources.
+     *
+     * @since 0.6.0
+     *
+     * @return A status code, zero on success, non-zero otherwise
+     */
+    lib::error_code defer_http_response();
+    
+    /// Send deferred HTTP Response (exception free)
+    /**
+     * Sends an http response to an HTTP connection that was deferred. This will
+     * send a complete response including all headers, status line, and body
+     * text. The connection will be closed afterwards.
+     *
+     * @since 0.6.0
+     *
+     * @param ec A status code, zero on success, non-zero otherwise
+     */
+    void send_http_response(lib::error_code & ec);
+    
+    /// Send deferred HTTP Response
+    void send_http_response();
+    
+    // TODO HTTPNBIO: write_headers
+    // function that processes headers + status so far and writes it to the wire
+    // beginning the HTTP response body state. This method will ignore anything
+    // in the response body.
+    
+    // TODO HTTPNBIO: write_body_message
+    // queues the specified message_buffer for async writing
+    
+    // TODO HTTPNBIO: finish connection
+    //
+    
+    // TODO HTTPNBIO: write_response
+    // Writes the whole response, headers + body and closes the connection
+    
+    
+
+    /////////////////////////////////////////////////////////////
+    // Pass-through access to the other connection information //
+    /////////////////////////////////////////////////////////////
+
+    /// Get Connection Handle
+    /**
+     * The connection handle is a token that can be shared outside the
+     * WebSocket++ core for the purposes of identifying a connection and
+     * sending it messages.
+     *
+     * @return A handle to the connection
+     */
+    connection_hdl get_handle() const {
+        return m_connection_hdl;
+    }
+
+    /// Get whether or not this connection is part of a server or client
+    /**
+     * @return whether or not the connection is attached to a server endpoint
+     */
+    bool is_server() const {
+        return m_is_server;
+    }
+
+    /// Return the same origin policy origin value from the opening request.
+    /**
+     * This value is available after the HTTP request has been fully read and
+     * may be called from any thread.
+     *
+     * @return The connection's origin value from the opening handshake.
+     */
+    std::string const & get_origin() const;
+
+    /// Return the connection state.
+    /**
+     * Values can be connecting, open, closing, and closed
+     *
+     * @return The connection's current state.
+     */
+    session::state::value get_state() const;
+
+
+    /// Get the WebSocket close code sent by this endpoint.
+    /**
+     * @return The WebSocket close code sent by this endpoint.
+     */
+    close::status::value get_local_close_code() const {
+        return m_local_close_code;
+    }
+
+    /// Get the WebSocket close reason sent by this endpoint.
+    /**
+     * @return The WebSocket close reason sent by this endpoint.
+     */
+    std::string const & get_local_close_reason() const {
+        return m_local_close_reason;
+    }
+
+    /// Get the WebSocket close code sent by the remote endpoint.
+    /**
+     * @return The WebSocket close code sent by the remote endpoint.
+     */
+    close::status::value get_remote_close_code() const {
+        return m_remote_close_code;
+    }
+
+    /// Get the WebSocket close reason sent by the remote endpoint.
+    /**
+     * @return The WebSocket close reason sent by the remote endpoint.
+     */
+    std::string const & get_remote_close_reason() const {
+        return m_remote_close_reason;
+    }
+
+    /// Get the internal error code for a closed/failed connection
+    /**
+     * Retrieves a machine readable detailed error code indicating the reason
+     * that the connection was closed or failed. Valid only after the close or
+     * fail handler is called.
+     *
+     * @return Error code indicating the reason the connection was closed or
+     * failed
+     */
+    lib::error_code get_ec() const {
+        return m_ec;
+    }
+
+    /// Get a message buffer
+    /**
+     * Warning: The API related to directly sending message buffers may change
+     * before the 1.0 release. If you plan to use it, please keep an eye on any
+     * breaking changes notifications in future release notes. Also if you have
+     * any feedback about usage and capabilities now is a great time to provide
+     * it.
+     *
+     * Message buffers are used to store message payloads and other message
+     * metadata.
+     *
+     * The size parameter is a hint only. Your final payload does not need to
+     * match it. There may be some performance benefits if the initial size
+     * guess is equal to or slightly higher than the final payload size.
+     *
+     * @param op The opcode for the new message
+     * @param size A hint to optimize the initial allocation of payload space.
+     * @return A new message buffer
+     */
+    message_ptr get_message(websocketpp::frame::opcode::value op, size_t size)
+        const
+    {
+        return m_msg_manager->get_message(op, size);
+    }
+
+    ////////////////////////////////////////////////////////////////////////
+    // The remaining public member functions are for internal/policy use  //
+    // only. Do not call from application code unless you understand what //
+    // you are doing.                                                     //
+    ////////////////////////////////////////////////////////////////////////
+
+    
+
+    void read_handshake(size_t num_bytes);
+
+    void handle_read_handshake(lib::error_code const & ec,
+        size_t bytes_transferred);
+    void handle_read_http_response(lib::error_code const & ec,
+        size_t bytes_transferred);
+
+    
+    void handle_write_http_response(lib::error_code const & ec);
+    void handle_send_http_request(lib::error_code const & ec);
+
+    void handle_open_handshake_timeout(lib::error_code const & ec);
+    void handle_close_handshake_timeout(lib::error_code const & ec);
+
+    void handle_read_frame(lib::error_code const & ec, size_t bytes_transferred);
+    void read_frame();
+
+    /// Get array of WebSocket protocol versions that this connection supports.
+    std::vector<int> const & get_supported_versions() const;
+
+    /// Sets the handler for a terminating connection. Should only be used
+    /// internally by the endpoint class.
+    void set_termination_handler(termination_handler new_handler);
+
+    void terminate(lib::error_code const & ec);
+    void handle_terminate(terminate_status tstat, lib::error_code const & ec);
+
+    /// Checks if there are frames in the send queue and if there are sends one
+    /**
+     * \todo unit tests
+     *
+     * This method locks the m_write_lock mutex
+     */
+    void write_frame();
+
+    /// Process the results of a frame write operation and start the next write
+    /**
+     * \todo unit tests
+     *
+     * This method locks the m_write_lock mutex
+     *
+     * @param terminate Whether or not to terminate the connection upon
+     * completion of this write.
+     *
+     * @param ec A status code from the transport layer, zero on success,
+     * non-zero otherwise.
+     */
+    void handle_write_frame(lib::error_code const & ec);
+// protected:
+    // This set of methods would really like to be protected, but doing so 
+    // requires that the endpoint be able to friend the connection. This is 
+    // allowed with C++11, but not prior versions
+
+    /// Start the connection state machine
+    void start();
+
+    /// Set Connection Handle
+    /**
+     * The connection handle is a token that can be shared outside the
+     * WebSocket++ core for the purposes of identifying a connection and
+     * sending it messages.
+     *
+     * @param hdl A connection_hdl that the connection will use to refer
+     * to itself.
+     */
+    void set_handle(connection_hdl hdl) {
+        m_connection_hdl = hdl;
+        transport_con_type::set_handle(hdl);
+    }
+protected:
+    void handle_transport_init(lib::error_code const & ec);
+
+    /// Set m_processor based on information in m_request. Set m_response
+    /// status and return an error code indicating status.
+    lib::error_code initialize_processor();
+
+    /// Perform WebSocket handshake validation of m_request using m_processor.
+    /// set m_response and return an error code indicating status.
+    lib::error_code process_handshake_request();
+private:
+    
+
+    /// Completes m_response, serializes it, and sends it out on the wire.
+    void write_http_response(lib::error_code const & ec);
+
+    /// Sends an opening WebSocket connect request
+    void send_http_request();
+
+    /// Alternate path for write_http_response in error conditions
+    void write_http_response_error(lib::error_code const & ec);
+
+    /// Process control message
+    /**
+     *
+     */
+    void process_control_frame(message_ptr msg);
+
+    /// Send close acknowledgement
+    /**
+     * If no arguments are present no close code/reason will be specified.
+     *
+     * Note: the close code/reason values provided here may be overrided by
+     * other settings (such as silent close).
+     *
+     * @param code The close code to send
+     * @param reason The close reason to send
+     * @return A status code, zero on success, non-zero otherwise
+     */
+    lib::error_code send_close_ack(close::status::value code =
+        close::status::blank, std::string const & reason = std::string());
+
+    /// Send close frame
+    /**
+     * If no arguments are present no close code/reason will be specified.
+     *
+     * Note: the close code/reason values provided here may be overrided by
+     * other settings (such as silent close).
+     *
+     * The ack flag determines what to do in the case of a blank status and
+     * whether or not to terminate the TCP connection after sending it.
+     *
+     * @param code The close code to send
+     * @param reason The close reason to send
+     * @param ack Whether or not this is an acknowledgement close frame
+     * @return A status code, zero on success, non-zero otherwise
+     */
+    lib::error_code send_close_frame(close::status::value code =
+        close::status::blank, std::string const & reason = std::string(), bool ack = false,
+        bool terminal = false);
+
+    /// Get a pointer to a new WebSocket protocol processor for a given version
+    /**
+     * @param version Version number of the WebSocket protocol to get a
+     * processor for. Negative values indicate invalid/unknown versions and will
+     * always return a null ptr
+     *
+     * @return A shared_ptr to a new instance of the appropriate processor or a
+     * null ptr if there is no installed processor that matches the version
+     * number.
+     */
+    processor_ptr get_processor(int version) const;
+
+    /// Add a message to the write queue
+    /**
+     * Adds a message to the write queue and updates any associated shared state
+     *
+     * Must be called while holding m_write_lock
+     *
+     * @todo unit tests
+     *
+     * @param msg The message to push
+     */
+    void write_push(message_ptr msg);
+
+    /// Pop a message from the write queue
+    /**
+     * Removes and returns a message from the write queue and updates any
+     * associated shared state.
+     *
+     * Must be called while holding m_write_lock
+     *
+     * @todo unit tests
+     *
+     * @return the message_ptr at the front of the queue
+     */
+    message_ptr write_pop();
+
+    /// Prints information about the incoming connection to the access log
+    /**
+     * Prints information about the incoming connection to the access log.
+     * Includes: connection type, websocket version, remote endpoint, user agent
+     * path, status code.
+     */
+    void log_open_result();
+
+    /// Prints information about a connection being closed to the access log
+    /**
+     * Includes: local and remote close codes and reasons
+     */
+    void log_close_result();
+
+    /// Prints information about a connection being failed to the access log
+    /**
+     * Includes: error code and message for why it was failed
+     */
+    void log_fail_result();
+    
+    /// Prints information about HTTP connections
+    /**
+     * Includes: TODO
+     */
+    void log_http_result();
+
+    /// Prints information about an arbitrary error code on the specified channel
+    template <typename error_type>
+    void log_err(log::level l, char const * msg, error_type const & ec) {
+        std::stringstream s;
+        s << msg << " error: " << ec << " (" << ec.message() << ")";
+        m_elog->write(l, s.str());
+    }
+
+    // internal handler functions
+    read_handler            m_handle_read_frame;
+    write_frame_handler     m_write_frame_handler;
+
+    // static settings
+    std::string const       m_user_agent;
+
+    /// Pointer to the connection handle
+    connection_hdl          m_connection_hdl;
+
+    /// Handler objects
+    open_handler            m_open_handler;
+    close_handler           m_close_handler;
+    fail_handler            m_fail_handler;
+    ping_handler            m_ping_handler;
+    pong_handler            m_pong_handler;
+    pong_timeout_handler    m_pong_timeout_handler;
+    interrupt_handler       m_interrupt_handler;
+    http_handler            m_http_handler;
+    validate_handler        m_validate_handler;
+    message_handler         m_message_handler;
+
+    /// constant values
+    long                    m_open_handshake_timeout_dur;
+    long                    m_close_handshake_timeout_dur;
+    long                    m_pong_timeout_dur;
+    size_t                  m_max_message_size;
+
+    /// External connection state
+    /**
+     * Lock: m_connection_state_lock
+     */
+    session::state::value   m_state;
+
+    /// Internal connection state
+    /**
+     * Lock: m_connection_state_lock
+     */
+    istate_type             m_internal_state;
+
+    mutable mutex_type      m_connection_state_lock;
+
+    /// The lock used to protect the message queue
+    /**
+     * Serializes access to the write queue as well as shared state within the
+     * processor.
+     */
+    mutex_type              m_write_lock;
+
+    // connection resources
+    char                    m_buf[config::connection_read_buffer_size];
+    size_t                  m_buf_cursor;
+    termination_handler     m_termination_handler;
+    con_msg_manager_ptr     m_msg_manager;
+    timer_ptr               m_handshake_timer;
+    timer_ptr               m_ping_timer;
+
+    /// @todo this is not memory efficient. this value is not used after the
+    /// handshake.
+    std::string m_handshake_buffer;
+
+    /// Pointer to the processor object for this connection
+    /**
+     * The processor provides functionality that is specific to the WebSocket
+     * protocol version that the client has negotiated. It also contains all of
+     * the state necessary to encode and decode the incoming and outgoing
+     * WebSocket byte streams
+     *
+     * Use of the prepare_data_frame method requires lock: m_write_lock
+     */
+    processor_ptr           m_processor;
+
+    /// Queue of unsent outgoing messages
+    /**
+     * Lock: m_write_lock
+     */
+    std::queue<message_ptr> m_send_queue;
+
+    /// Size in bytes of the outstanding payloads in the write queue
+    /**
+     * Lock: m_write_lock
+     */
+    size_t m_send_buffer_size;
+
+    /// buffer holding the various parts of the current message being writen
+    /**
+     * Lock m_write_lock
+     */
+    std::vector<transport::buffer> m_send_buffer;
+
+    /// a list of pointers to hold on to the messages being written to keep them
+    /// from going out of scope before the write is complete.
+    std::vector<message_ptr> m_current_msgs;
+
+    /// True if there is currently an outstanding transport write
+    /**
+     * Lock m_write_lock
+     */
+    bool m_write_flag;
+
+    /// True if this connection is presently reading new data
+    bool m_read_flag;
+
+    // connection data
+    request_type            m_request;
+    response_type           m_response;
+    uri_ptr                 m_uri;
+    std::string             m_subprotocol;
+
+    // connection data that might not be necessary to keep around for the life
+    // of the whole connection.
+    std::vector<std::string> m_requested_subprotocols;
+
+    bool const              m_is_server;
+    const lib::shared_ptr<alog_type> m_alog;
+    const lib::shared_ptr<elog_type> m_elog;
+
+    rng_type & m_rng;
+
+    // Close state
+    /// Close code that was sent on the wire by this endpoint
+    close::status::value    m_local_close_code;
+
+    /// Close reason that was sent on the wire by this endpoint
+    std::string             m_local_close_reason;
+
+    /// Close code that was received on the wire from the remote endpoint
+    close::status::value    m_remote_close_code;
+
+    /// Close reason that was received on the wire from the remote endpoint
+    std::string             m_remote_close_reason;
+
+    /// Detailed internal error code
+    lib::error_code m_ec;
+    
+    /// A flag that gets set once it is determined that the connection is an
+    /// HTTP connection and not a WebSocket one.
+    bool m_is_http;
+    
+    /// A flag that gets set when the completion of an http connection is
+    /// deferred until later.
+    session::http_state::value m_http_state;
+
+    bool m_was_clean;
+};
+
+} // namespace websocketpp
+
+#include <websocketpp/impl/connection_impl.hpp>
+
+#endif // WEBSOCKETPP_CONNECTION_HPP
diff --git a/subprojects/websocketpp/websocketpp/connection_base.hpp b/subprojects/websocketpp/websocketpp/connection_base.hpp
new file mode 100644
index 000000000..2e700962f
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/connection_base.hpp
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONNECTION_BASE_HPP
+#define WEBSOCKETPP_CONNECTION_BASE_HPP
+
+namespace websocketpp {
+
+/// Stub for user supplied base class.
+class connection_base {};
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONNECTION_BASE_HPP
diff --git a/subprojects/websocketpp/websocketpp/endpoint.hpp b/subprojects/websocketpp/websocketpp/endpoint.hpp
new file mode 100644
index 000000000..c124b1d9a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/endpoint.hpp
@@ -0,0 +1,700 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_ENDPOINT_HPP
+#define WEBSOCKETPP_ENDPOINT_HPP
+
+#include <websocketpp/connection.hpp>
+
+#include <websocketpp/logger/levels.hpp>
+#include <websocketpp/version.hpp>
+
+#include <string>
+
+namespace websocketpp {
+
+/// Creates and manages connections associated with a WebSocket endpoint
+template <typename connection, typename config>
+class endpoint : public config::transport_type, public config::endpoint_base {
+public:
+    // Import appropriate types from our helper class
+    // See endpoint_types for more details.
+    typedef endpoint<connection,config> type;
+
+    /// Type of the transport component of this endpoint
+    typedef typename config::transport_type transport_type;
+    /// Type of the concurrency component of this endpoint
+    typedef typename config::concurrency_type concurrency_type;
+
+    /// Type of the connections that this endpoint creates
+    typedef connection connection_type;
+    /// Shared pointer to connection_type
+    typedef typename connection_type::ptr connection_ptr;
+    /// Weak pointer to connection type
+    typedef typename connection_type::weak_ptr connection_weak_ptr;
+
+    /// Type of the transport component of the connections that this endpoint
+    /// creates
+    typedef typename transport_type::transport_con_type transport_con_type;
+    /// Type of a shared pointer to the transport component of the connections
+    /// that this endpoint creates.
+    typedef typename transport_con_type::ptr transport_con_ptr;
+
+    /// Type of message_handler
+    typedef typename connection_type::message_handler message_handler;
+    /// Type of message pointers that this endpoint uses
+    typedef typename connection_type::message_ptr message_ptr;
+
+    /// Type of error logger
+    typedef typename config::elog_type elog_type;
+    /// Type of access logger
+    typedef typename config::alog_type alog_type;
+
+    /// Type of our concurrency policy's scoped lock object
+    typedef typename concurrency_type::scoped_lock_type scoped_lock_type;
+    /// Type of our concurrency policy's mutex object
+    typedef typename concurrency_type::mutex_type mutex_type;
+
+    /// Type of RNG
+    typedef typename config::rng_type rng_type;
+
+    // TODO: organize these
+    typedef typename connection_type::termination_handler termination_handler;
+
+    // This would be ideal. Requires C++11 though
+    //friend connection;
+
+    explicit endpoint(bool p_is_server)
+      : m_alog(new alog_type(config::alog_level, log::channel_type_hint::access))
+      , m_elog(new elog_type(config::elog_level, log::channel_type_hint::error))
+      , m_user_agent(::websocketpp::user_agent)
+      , m_open_handshake_timeout_dur(config::timeout_open_handshake)
+      , m_close_handshake_timeout_dur(config::timeout_close_handshake)
+      , m_pong_timeout_dur(config::timeout_pong)
+      , m_max_message_size(config::max_message_size)
+      , m_max_http_body_size(config::max_http_body_size)
+      , m_is_server(p_is_server)
+    {
+        m_alog->set_channels(config::alog_level);
+        m_elog->set_channels(config::elog_level);
+
+        m_alog->write(log::alevel::devel, "endpoint constructor");
+
+        transport_type::init_logging(m_alog, m_elog);
+    }
+
+
+    /// Destructor
+    ~endpoint<connection,config>() {}
+
+    #ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+        // no copy constructor because endpoints are not copyable
+        endpoint(endpoint &) = delete;
+    
+        // no copy assignment operator because endpoints are not copyable
+        endpoint & operator=(endpoint const &) = delete;
+    #endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+
+    #ifdef _WEBSOCKETPP_MOVE_SEMANTICS_
+        /// Move constructor
+        endpoint(endpoint && o) 
+         : config::transport_type(std::move(o))
+         , config::endpoint_base(std::move(o))
+         , m_alog(std::move(o.m_alog))
+         , m_elog(std::move(o.m_elog))
+         , m_user_agent(std::move(o.m_user_agent))
+         , m_open_handler(std::move(o.m_open_handler))
+         
+         , m_close_handler(std::move(o.m_close_handler))
+         , m_fail_handler(std::move(o.m_fail_handler))
+         , m_ping_handler(std::move(o.m_ping_handler))
+         , m_pong_handler(std::move(o.m_pong_handler))
+         , m_pong_timeout_handler(std::move(o.m_pong_timeout_handler))
+         , m_interrupt_handler(std::move(o.m_interrupt_handler))
+         , m_http_handler(std::move(o.m_http_handler))
+         , m_validate_handler(std::move(o.m_validate_handler))
+         , m_message_handler(std::move(o.m_message_handler))
+
+         , m_open_handshake_timeout_dur(o.m_open_handshake_timeout_dur)
+         , m_close_handshake_timeout_dur(o.m_close_handshake_timeout_dur)
+         , m_pong_timeout_dur(o.m_pong_timeout_dur)
+         , m_max_message_size(o.m_max_message_size)
+         , m_max_http_body_size(o.m_max_http_body_size)
+
+         , m_rng(std::move(o.m_rng))
+         , m_is_server(o.m_is_server)         
+        {}
+
+    #ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+        // no move assignment operator because of const member variables
+        endpoint & operator=(endpoint &&) = delete;
+    #endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+
+    #endif // _WEBSOCKETPP_MOVE_SEMANTICS_
+
+
+    /// Returns the user agent string that this endpoint will use
+    /**
+     * Returns the user agent string that this endpoint will use when creating
+     * new connections.
+     *
+     * The default value for this version is stored in websocketpp::user_agent
+     *
+     * @return The user agent string.
+     */
+    std::string get_user_agent() const {
+        scoped_lock_type guard(m_mutex);
+        return m_user_agent;
+    }
+
+    /// Sets the user agent string that this endpoint will use
+    /**
+     * Sets the identifier that this endpoint will use when creating new
+     * connections. Changing this value will only affect future connections.
+     * For client endpoints this will be sent as the "User-Agent" header in
+     * outgoing requests. For server endpoints this will be sent in the "Server"
+     * response header.
+     *
+     * Setting this value to the empty string will suppress the use of the
+     * Server and User-Agent headers. This is typically done to hide
+     * implementation details for security purposes.
+     *
+     * For best results set this before accepting or opening connections.
+     *
+     * The default value for this version is stored in websocketpp::user_agent
+     *
+     * This can be overridden on an individual connection basis by setting a
+     * custom "Server" header during the validate handler or "User-Agent"
+     * header on a connection before calling connect().
+     *
+     * @param ua The string to set the user agent to.
+     */
+    void set_user_agent(std::string const & ua) {
+        scoped_lock_type guard(m_mutex);
+        m_user_agent = ua;
+    }
+
+    /// Returns whether or not this endpoint is a server.
+    /**
+     * @return Whether or not this endpoint is a server
+     */
+    bool is_server() const {
+        return m_is_server;
+    }
+
+    /********************************/
+    /* Pass-through logging adaptor */
+    /********************************/
+
+    /// Set Access logging channel
+    /**
+     * Set the access logger's channel value. The value is a number whose
+     * interpretation depends on the logging policy in use.
+     *
+     * @param channels The channel value(s) to set
+     */
+    void set_access_channels(log::level channels) {
+        m_alog->set_channels(channels);
+    }
+
+    /// Clear Access logging channels
+    /**
+     * Clear the access logger's channel value. The value is a number whose
+     * interpretation depends on the logging policy in use.
+     *
+     * @param channels The channel value(s) to clear
+     */
+    void clear_access_channels(log::level channels) {
+        m_alog->clear_channels(channels);
+    }
+
+    /// Set Error logging channel
+    /**
+     * Set the error logger's channel value. The value is a number whose
+     * interpretation depends on the logging policy in use.
+     *
+     * @param channels The channel value(s) to set
+     */
+    void set_error_channels(log::level channels) {
+        m_elog->set_channels(channels);
+    }
+
+    /// Clear Error logging channels
+    /**
+     * Clear the error logger's channel value. The value is a number whose
+     * interpretation depends on the logging policy in use.
+     *
+     * @param channels The channel value(s) to clear
+     */
+    void clear_error_channels(log::level channels) {
+        m_elog->clear_channels(channels);
+    }
+
+    /// Get reference to access logger
+    /**
+     * @return A reference to the access logger
+     */
+    alog_type & get_alog() {
+        return *m_alog;
+    }
+
+    /// Get reference to error logger
+    /**
+     * @return A reference to the error logger
+     */
+    elog_type & get_elog() {
+        return *m_elog;
+    }
+
+    /*************************/
+    /* Set Handler functions */
+    /*************************/
+
+    void set_open_handler(open_handler h) {
+        m_alog->write(log::alevel::devel,"set_open_handler");
+        scoped_lock_type guard(m_mutex);
+        m_open_handler = h;
+    }
+    void set_close_handler(close_handler h) {
+        m_alog->write(log::alevel::devel,"set_close_handler");
+        scoped_lock_type guard(m_mutex);
+        m_close_handler = h;
+    }
+    void set_fail_handler(fail_handler h) {
+        m_alog->write(log::alevel::devel,"set_fail_handler");
+        scoped_lock_type guard(m_mutex);
+        m_fail_handler = h;
+    }
+    void set_ping_handler(ping_handler h) {
+        m_alog->write(log::alevel::devel,"set_ping_handler");
+        scoped_lock_type guard(m_mutex);
+        m_ping_handler = h;
+    }
+    void set_pong_handler(pong_handler h) {
+        m_alog->write(log::alevel::devel,"set_pong_handler");
+        scoped_lock_type guard(m_mutex);
+        m_pong_handler = h;
+    }
+    void set_pong_timeout_handler(pong_timeout_handler h) {
+        m_alog->write(log::alevel::devel,"set_pong_timeout_handler");
+        scoped_lock_type guard(m_mutex);
+        m_pong_timeout_handler = h;
+    }
+    void set_interrupt_handler(interrupt_handler h) {
+        m_alog->write(log::alevel::devel,"set_interrupt_handler");
+        scoped_lock_type guard(m_mutex);
+        m_interrupt_handler = h;
+    }
+    void set_http_handler(http_handler h) {
+        m_alog->write(log::alevel::devel,"set_http_handler");
+        scoped_lock_type guard(m_mutex);
+        m_http_handler = h;
+    }
+    void set_validate_handler(validate_handler h) {
+        m_alog->write(log::alevel::devel,"set_validate_handler");
+        scoped_lock_type guard(m_mutex);
+        m_validate_handler = h;
+    }
+    void set_message_handler(message_handler h) {
+        m_alog->write(log::alevel::devel,"set_message_handler");
+        scoped_lock_type guard(m_mutex);
+        m_message_handler = h;
+    }
+
+    //////////////////////////////////////////
+    // Connection timeouts and other limits //
+    //////////////////////////////////////////
+
+    /// Set open handshake timeout
+    /**
+     * Sets the length of time the library will wait after an opening handshake
+     * has been initiated before cancelling it. This can be used to prevent
+     * excessive wait times for outgoing clients or excessive resource usage
+     * from broken clients or DoS attacks on servers.
+     *
+     * Connections that time out will have their fail handlers called with the
+     * open_handshake_timeout error code.
+     *
+     * The default value is specified via the compile time config value
+     * 'timeout_open_handshake'. The default value in the core config
+     * is 5000ms. A value of 0 will disable the timer entirely.
+     *
+     * To be effective, the transport you are using must support timers. See
+     * the documentation for your transport policy for details about its
+     * timer support.
+     *
+     * @param dur The length of the open handshake timeout in ms
+     */
+    void set_open_handshake_timeout(long dur) {
+        scoped_lock_type guard(m_mutex);
+        m_open_handshake_timeout_dur = dur;
+    }
+
+    /// Set close handshake timeout
+    /**
+     * Sets the length of time the library will wait after a closing handshake
+     * has been initiated before cancelling it. This can be used to prevent
+     * excessive wait times for outgoing clients or excessive resource usage
+     * from broken clients or DoS attacks on servers.
+     *
+     * Connections that time out will have their close handlers called with the
+     * close_handshake_timeout error code.
+     *
+     * The default value is specified via the compile time config value
+     * 'timeout_close_handshake'. The default value in the core config
+     * is 5000ms. A value of 0 will disable the timer entirely.
+     *
+     * To be effective, the transport you are using must support timers. See
+     * the documentation for your transport policy for details about its
+     * timer support.
+     *
+     * @param dur The length of the close handshake timeout in ms
+     */
+    void set_close_handshake_timeout(long dur) {
+        scoped_lock_type guard(m_mutex);
+        m_close_handshake_timeout_dur = dur;
+    }
+
+    /// Set pong timeout
+    /**
+     * Sets the length of time the library will wait for a pong response to a
+     * ping. This can be used as a keepalive or to detect broken  connections.
+     *
+     * Pong responses that time out will have the pong timeout handler called.
+     *
+     * The default value is specified via the compile time config value
+     * 'timeout_pong'. The default value in the core config
+     * is 5000ms. A value of 0 will disable the timer entirely.
+     *
+     * To be effective, the transport you are using must support timers. See
+     * the documentation for your transport policy for details about its
+     * timer support.
+     *
+     * @param dur The length of the pong timeout in ms
+     */
+    void set_pong_timeout(long dur) {
+        scoped_lock_type guard(m_mutex);
+        m_pong_timeout_dur = dur;
+    }
+
+    /// Get default maximum message size
+    /**
+     * Get the default maximum message size that will be used for new 
+     * connections created by this endpoint. The maximum message size determines
+     * the point at which the connection will fail a connection with the 
+     * message_too_big protocol error.
+     *
+     * The default is set by the max_message_size value from the template config
+     *
+     * @since 0.3.0
+     */
+    size_t get_max_message_size() const {
+        return m_max_message_size;
+    }
+    
+    /// Set default maximum message size
+    /**
+     * Set the default maximum message size that will be used for new 
+     * connections created by this endpoint. Maximum message size determines the
+     * point at which the connection will fail a connection with the
+     * message_too_big protocol error.
+     *
+     * The default is set by the max_message_size value from the template config
+     *
+     * @since 0.3.0
+     *
+     * @param new_value The value to set as the maximum message size.
+     */
+    void set_max_message_size(size_t new_value) {
+        m_max_message_size = new_value;
+    }
+
+    /// Get maximum HTTP message body size
+    /**
+     * Get maximum HTTP message body size. Maximum message body size determines
+     * the point at which the connection will stop reading an HTTP request whose
+     * body is too large.
+     *
+     * The default is set by the max_http_body_size value from the template
+     * config
+     *
+     * @since 0.5.0
+     *
+     * @return The maximum HTTP message body size
+     */
+    size_t get_max_http_body_size() const {
+        return m_max_http_body_size;
+    }
+    
+    /// Set maximum HTTP message body size
+    /**
+     * Set maximum HTTP message body size. Maximum message body size determines
+     * the point at which the connection will stop reading an HTTP request whose
+     * body is too large.
+     *
+     * The default is set by the max_http_body_size value from the template
+     * config
+     *
+     * @since 0.5.1
+     *
+     * @param new_value The value to set as the maximum message size.
+     */
+    void set_max_http_body_size(size_t new_value) {
+        m_max_http_body_size = new_value;
+    }
+
+    /*************************************/
+    /* Connection pass through functions */
+    /*************************************/
+
+    /**
+     * These functions act as adaptors to their counterparts in connection. They
+     * can produce one additional type of error, the bad_connection error, that
+     * indicates that the conversion from connection_hdl to connection_ptr
+     * failed due to the connection not existing anymore. Each method has a
+     * default and an exception free varient.
+     */
+
+    void interrupt(connection_hdl hdl, lib::error_code & ec);
+    void interrupt(connection_hdl hdl);
+
+    /// Pause reading of new data (exception free)
+    /**
+     * Signals to the connection to halt reading of new data. While reading is 
+     * paused, the connection will stop reading from its associated socket. In
+     * turn this will result in TCP based flow control kicking in and slowing
+     * data flow from the remote endpoint.
+     *
+     * This is useful for applications that push new requests to a queue to be 
+     * processed by another thread and need a way to signal when their request
+     * queue is full without blocking the network processing thread.
+     *
+     * Use `resume_reading()` to resume.
+     *
+     * If supported by the transport this is done asynchronously. As such
+     * reading may not stop until the current read operation completes. 
+     * Typically you can expect to receive no more bytes after initiating a read
+     * pause than the size of the read buffer.
+     *
+     * If reading is paused for this connection already nothing is changed.
+     */
+    void pause_reading(connection_hdl hdl, lib::error_code & ec);
+    
+    /// Pause reading of new data
+    void pause_reading(connection_hdl hdl);
+
+    /// Resume reading of new data (exception free)
+    /**
+     * Signals to the connection to resume reading of new data after it was 
+     * paused by `pause_reading()`.
+     *
+     * If reading is not paused for this connection already nothing is changed.
+     */
+    void resume_reading(connection_hdl hdl, lib::error_code & ec);
+
+    /// Resume reading of new data
+    void resume_reading(connection_hdl hdl);
+
+    /// Send deferred HTTP Response
+    /**
+     * Sends an http response to an HTTP connection that was deferred. This will
+     * send a complete response including all headers, status line, and body
+     * text. The connection will be closed afterwards.
+     *
+     * Exception free variant
+     *
+     * @since 0.6.0
+     *
+     * @param hdl The connection to send the response on
+     * @param ec A status code, zero on success, non-zero otherwise
+     */
+    void send_http_response(connection_hdl hdl, lib::error_code & ec);
+        
+    /// Send deferred HTTP Response (exception free)
+    /**
+     * Sends an http response to an HTTP connection that was deferred. This will
+     * send a complete response including all headers, status line, and body
+     * text. The connection will be closed afterwards.
+     *
+     * Exception variant
+     *
+     * @since 0.6.0
+     *
+     * @param hdl The connection to send the response on
+     */
+    void send_http_response(connection_hdl hdl);
+
+    /// Create a message and add it to the outgoing send queue (exception free)
+    /**
+     * Convenience method to send a message given a payload string and an opcode
+     *
+     * @param [in] hdl The handle identifying the connection to send via.
+     * @param [in] payload The payload string to generated the message with
+     * @param [in] op The opcode to generated the message with.
+     * @param [out] ec A code to fill in for errors
+     */
+    void send(connection_hdl hdl, std::string const & payload,
+        frame::opcode::value op, lib::error_code & ec);
+    /// Create a message and add it to the outgoing send queue
+    /**
+     * Convenience method to send a message given a payload string and an opcode
+     *
+     * @param [in] hdl The handle identifying the connection to send via.
+     * @param [in] payload The payload string to generated the message with
+     * @param [in] op The opcode to generated the message with.
+     * @param [out] ec A code to fill in for errors
+     */
+    void send(connection_hdl hdl, std::string const & payload,
+        frame::opcode::value op);
+
+    void send(connection_hdl hdl, void const * payload, size_t len,
+        frame::opcode::value op, lib::error_code & ec);
+    void send(connection_hdl hdl, void const * payload, size_t len,
+        frame::opcode::value op);
+
+    void send(connection_hdl hdl, message_ptr msg, lib::error_code & ec);
+    void send(connection_hdl hdl, message_ptr msg);
+
+    void close(connection_hdl hdl, close::status::value const code,
+        std::string const & reason, lib::error_code & ec);
+    void close(connection_hdl hdl, close::status::value const code,
+        std::string const & reason);
+
+    /// Send a ping to a specific connection
+    /**
+     * @since 0.3.0-alpha3
+     *
+     * @param [in] hdl The connection_hdl of the connection to send to.
+     * @param [in] payload The payload string to send.
+     * @param [out] ec A reference to an error code to fill in
+     */
+    void ping(connection_hdl hdl, std::string const & payload,
+        lib::error_code & ec);
+    /// Send a ping to a specific connection
+    /**
+     * Exception variant of `ping`
+     *
+     * @since 0.3.0-alpha3
+     *
+     * @param [in] hdl The connection_hdl of the connection to send to.
+     * @param [in] payload The payload string to send.
+     */
+    void ping(connection_hdl hdl, std::string const & payload);
+
+    /// Send a pong to a specific connection
+    /**
+     * @since 0.3.0-alpha3
+     *
+     * @param [in] hdl The connection_hdl of the connection to send to.
+     * @param [in] payload The payload string to send.
+     * @param [out] ec A reference to an error code to fill in
+     */
+    void pong(connection_hdl hdl, std::string const & payload,
+        lib::error_code & ec);
+    /// Send a pong to a specific connection
+    /**
+     * Exception variant of `pong`
+     *
+     * @since 0.3.0-alpha3
+     *
+     * @param [in] hdl The connection_hdl of the connection to send to.
+     * @param [in] payload The payload string to send.
+     */
+    void pong(connection_hdl hdl, std::string const & payload);
+
+    /// Retrieves a connection_ptr from a connection_hdl (exception free)
+    /**
+     * Converting a weak pointer to shared_ptr is not thread safe because the
+     * pointer could be deleted at any time.
+     *
+     * NOTE: This method may be called by handler to upgrade its handle to a
+     * full connection_ptr. That full connection may then be used safely for the
+     * remainder of the handler body. get_con_from_hdl and the resulting
+     * connection_ptr are NOT safe to use outside the handler loop.
+     *
+     * @param hdl The connection handle to translate
+     *
+     * @return the connection_ptr. May be NULL if the handle was invalid.
+     */
+    connection_ptr get_con_from_hdl(connection_hdl hdl, lib::error_code & ec) {
+        connection_ptr con = lib::static_pointer_cast<connection_type>(
+            hdl.lock());
+        if (!con) {
+            ec = error::make_error_code(error::bad_connection);
+        }
+        return con;
+    }
+
+    /// Retrieves a connection_ptr from a connection_hdl (exception version)
+    connection_ptr get_con_from_hdl(connection_hdl hdl) {
+        lib::error_code ec;
+        connection_ptr con = this->get_con_from_hdl(hdl,ec);
+        if (ec) {
+            throw exception(ec);
+        }
+        return con;
+    }
+protected:
+    connection_ptr create_connection();
+
+    lib::shared_ptr<alog_type> m_alog;
+    lib::shared_ptr<elog_type> m_elog;
+private:
+    // dynamic settings
+    std::string                 m_user_agent;
+
+    open_handler                m_open_handler;
+    close_handler               m_close_handler;
+    fail_handler                m_fail_handler;
+    ping_handler                m_ping_handler;
+    pong_handler                m_pong_handler;
+    pong_timeout_handler        m_pong_timeout_handler;
+    interrupt_handler           m_interrupt_handler;
+    http_handler                m_http_handler;
+    validate_handler            m_validate_handler;
+    message_handler             m_message_handler;
+
+    long                        m_open_handshake_timeout_dur;
+    long                        m_close_handshake_timeout_dur;
+    long                        m_pong_timeout_dur;
+    size_t                      m_max_message_size;
+    size_t                      m_max_http_body_size;
+
+    rng_type m_rng;
+
+    // static settings
+    bool const                  m_is_server;
+
+    // endpoint state
+    mutable mutex_type          m_mutex;
+};
+
+} // namespace websocketpp
+
+#include <websocketpp/impl/endpoint_impl.hpp>
+
+#endif // WEBSOCKETPP_ENDPOINT_HPP
diff --git a/subprojects/websocketpp/websocketpp/endpoint_base.hpp b/subprojects/websocketpp/websocketpp/endpoint_base.hpp
new file mode 100644
index 000000000..1ad1a44dc
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/endpoint_base.hpp
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_ENDPOINT_BASE_HPP
+#define WEBSOCKETPP_ENDPOINT_BASE_HPP
+
+namespace websocketpp {
+
+/// Stub for user supplied base class.
+class endpoint_base {};
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_ENDPOINT_BASE_HPP
diff --git a/subprojects/websocketpp/websocketpp/error.hpp b/subprojects/websocketpp/websocketpp/error.hpp
new file mode 100644
index 000000000..562fb6ed7
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/error.hpp
@@ -0,0 +1,277 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_ERROR_HPP
+#define WEBSOCKETPP_ERROR_HPP
+
+#include <exception>
+#include <string>
+#include <utility>
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+namespace websocketpp {
+
+/// Combination error code / string type for returning two values
+typedef std::pair<lib::error_code,std::string> err_str_pair;
+
+/// Library level error codes
+namespace error {
+enum value {
+    /// Catch-all library error
+    general = 1,
+
+    /// send attempted when endpoint write queue was full
+    send_queue_full,
+
+    /// Attempted an operation using a payload that was improperly formatted
+    /// ex: invalid UTF8 encoding on a text message.
+    payload_violation,
+
+    /// Attempted to open a secure connection with an insecure endpoint
+    endpoint_not_secure,
+
+    /// Attempted an operation that required an endpoint that is no longer
+    /// available. This is usually because the endpoint went out of scope
+    /// before a connection that it created.
+    endpoint_unavailable,
+
+    /// An invalid uri was supplied
+    invalid_uri,
+
+    /// The endpoint is out of outgoing message buffers
+    no_outgoing_buffers,
+
+    /// The endpoint is out of incoming message buffers
+    no_incoming_buffers,
+
+    /// The connection was in the wrong state for this operation
+    invalid_state,
+
+    /// Unable to parse close code
+    bad_close_code,
+
+    /// Close code is in a reserved range
+    reserved_close_code,
+
+    /// Close code is invalid
+    invalid_close_code,
+
+    /// Invalid UTF-8
+    invalid_utf8,
+
+    /// Invalid subprotocol
+    invalid_subprotocol,
+
+    /// An operation was attempted on a connection that did not exist or was
+    /// already deleted.
+    bad_connection,
+
+    /// Unit testing utility error code
+    test,
+
+    /// Connection creation attempted failed
+    con_creation_failed,
+
+    /// Selected subprotocol was not requested by the client
+    unrequested_subprotocol,
+
+    /// Attempted to use a client specific feature on a server endpoint
+    client_only,
+
+    /// Attempted to use a server specific feature on a client endpoint
+    server_only,
+
+    /// HTTP connection ended
+    http_connection_ended,
+
+    /// WebSocket opening handshake timed out
+    open_handshake_timeout,
+
+    /// WebSocket close handshake timed out
+    close_handshake_timeout,
+
+    /// Invalid port in URI
+    invalid_port,
+
+    /// An async accept operation failed because the underlying transport has been
+    /// requested to not listen for new connections anymore.
+    async_accept_not_listening,
+
+    /// The requested operation was canceled
+    operation_canceled,
+
+    /// Connection rejected
+    rejected,
+
+    /// Upgrade Required. This happens if an HTTP request is made to a
+    /// WebSocket++ server that doesn't implement an http handler
+    upgrade_required,
+
+    /// Invalid WebSocket protocol version
+    invalid_version,
+
+    /// Unsupported WebSocket protocol version
+    unsupported_version,
+
+    /// HTTP parse error
+    http_parse_error,
+    
+    /// Extension negotiation failed
+    extension_neg_failed
+}; // enum value
+
+
+class category : public lib::error_category {
+public:
+    category() {}
+
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case error::general:
+                return "Generic error";
+            case error::send_queue_full:
+                return "send queue full";
+            case error::payload_violation:
+                return "payload violation";
+            case error::endpoint_not_secure:
+                return "endpoint not secure";
+            case error::endpoint_unavailable:
+                return "endpoint not available";
+            case error::invalid_uri:
+                return "invalid uri";
+            case error::no_outgoing_buffers:
+                return "no outgoing message buffers";
+            case error::no_incoming_buffers:
+                return "no incoming message buffers";
+            case error::invalid_state:
+                return "invalid state";
+            case error::bad_close_code:
+                return "Unable to extract close code";
+            case error::invalid_close_code:
+                return "Extracted close code is in an invalid range";
+            case error::reserved_close_code:
+                return "Extracted close code is in a reserved range";
+            case error::invalid_utf8:
+                return "Invalid UTF-8";
+            case error::invalid_subprotocol:
+                return "Invalid subprotocol";
+            case error::bad_connection:
+                return "Bad Connection";
+            case error::test:
+                return "Test Error";
+            case error::con_creation_failed:
+                return "Connection creation attempt failed";
+            case error::unrequested_subprotocol:
+                return "Selected subprotocol was not requested by the client";
+            case error::client_only:
+                return "Feature not available on server endpoints";
+            case error::server_only:
+                return "Feature not available on client endpoints";
+            case error::http_connection_ended:
+                return "HTTP connection ended";
+            case error::open_handshake_timeout:
+                return "The opening handshake timed out";
+            case error::close_handshake_timeout:
+                return "The closing handshake timed out";
+            case error::invalid_port:
+                return "Invalid URI port";
+            case error::async_accept_not_listening:
+                return "Async Accept not listening";
+            case error::operation_canceled:
+                return "Operation canceled";
+            case error::rejected:
+                return "Connection rejected";
+            case error::upgrade_required:
+                return "Upgrade required";
+            case error::invalid_version:
+                return "Invalid version";
+            case error::unsupported_version:
+                return "Unsupported version";
+            case error::http_parse_error:
+                return "HTTP parse error";
+            case error::extension_neg_failed:
+                return "Extension negotiation failed";
+            default:
+                return "Unknown";
+        }
+    }
+};
+
+inline const lib::error_category& get_category() {
+    static category instance;
+    return instance;
+}
+
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace websocketpp
+
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum<websocketpp::error::value>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+
+namespace websocketpp {
+
+class exception : public std::exception {
+public:
+    exception(std::string const & msg, lib::error_code ec = make_error_code(error::general))
+      : m_msg(msg.empty() ? ec.message() : msg), m_code(ec)
+    {}
+
+    explicit exception(lib::error_code ec)
+      : m_msg(ec.message()), m_code(ec)
+    {}
+
+    ~exception() throw() {}
+
+    virtual char const * what() const throw() {
+        return m_msg.c_str();
+    }
+
+    lib::error_code code() const throw() {
+        return m_code;
+    }
+
+    const std::string m_msg;
+    lib::error_code m_code;
+};
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_ERROR_HPP
diff --git a/subprojects/websocketpp/websocketpp/extensions/extension.hpp b/subprojects/websocketpp/websocketpp/extensions/extension.hpp
new file mode 100644
index 000000000..f5fbd9f7b
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/extensions/extension.hpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_EXTENSION_HPP
+#define WEBSOCKETPP_EXTENSION_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+
+/**
+ * Some generic information about extensions
+ *
+ * Each extension object has an implemented flag. It can be retrieved by calling
+ * is_implemented(). This compile time flag indicates whether or not the object
+ * in question actually implements the extension or if it is a placeholder stub
+ *
+ * Each extension object also has an enabled flag. It can be retrieved by
+ * calling is_enabled(). This runtime flag indicates whether or not the
+ * extension has been negotiated for this connection.
+ */
+namespace extensions {
+
+namespace error {
+enum value {
+    /// Catch all
+    general = 1,
+
+    /// Extension disabled
+    disabled
+};
+
+class category : public lib::error_category {
+public:
+    category() {}
+
+    const char *name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.extension";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case general:
+                return "Generic extension error";
+            case disabled:
+                return "Use of methods from disabled extension";
+            default:
+                return "Unknown permessage-compress error";
+        }
+    }
+};
+
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace extensions
+} // namespace websocketpp
+
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum
+    <websocketpp::extensions::error::value>
+{
+    static const bool value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+
+#endif // WEBSOCKETPP_EXTENSION_HPP
diff --git a/subprojects/websocketpp/websocketpp/extensions/permessage_deflate/disabled.hpp b/subprojects/websocketpp/websocketpp/extensions/permessage_deflate/disabled.hpp
new file mode 100644
index 000000000..657309520
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/extensions/permessage_deflate/disabled.hpp
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_EXTENSION_PERMESSAGE_DEFLATE_DISABLED_HPP
+#define WEBSOCKETPP_EXTENSION_PERMESSAGE_DEFLATE_DISABLED_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/stdint.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <websocketpp/http/constants.hpp>
+#include <websocketpp/extensions/extension.hpp>
+
+#include <map>
+#include <string>
+#include <utility>
+
+namespace websocketpp {
+namespace extensions {
+namespace permessage_deflate {
+
+/// Stub class for use when disabling permessage_deflate extension
+/**
+ * This class is a stub that implements the permessage_deflate interface
+ * with minimal dependencies. It is used to disable permessage_deflate
+ * functionality at compile time without loading any unnecessary code.
+ */
+template <typename config>
+class disabled {
+    typedef std::pair<lib::error_code,std::string> err_str_pair;
+
+public:
+    /// Negotiate extension
+    /**
+     * The disabled extension always fails the negotiation with a disabled
+     * error.
+     *
+     * @param offer Attribute from client's offer
+     * @return Status code and value to return to remote endpoint
+     */
+    err_str_pair negotiate(http::attribute_list const &) {
+        return make_pair(make_error_code(error::disabled),std::string());
+    }
+
+    /// Initialize state
+    /**
+     * For the disabled extension state initialization is a no-op.
+     *
+     * @param is_server True to initialize as a server, false for a client.
+     * @return A code representing the error that occurred, if any
+     */
+    lib::error_code init(bool) {
+        return lib::error_code();
+    }
+
+    /// Returns true if the extension is capable of providing
+    /// permessage_deflate functionality
+    bool is_implemented() const {
+        return false;
+    }
+
+    /// Returns true if permessage_deflate functionality is active for this
+    /// connection
+    bool is_enabled() const {
+        return false;
+    }
+
+    /// Generate extension offer
+    /**
+     * Creates an offer string to include in the Sec-WebSocket-Extensions
+     * header of outgoing client requests.
+     *
+     * @return A WebSocket extension offer string for this extension
+     */
+    std::string generate_offer() const {
+        return "";
+    }
+
+    /// Compress bytes
+    /**
+     * @param [in] in String to compress
+     * @param [out] out String to append compressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code compress(std::string const &, std::string &) {
+        return make_error_code(error::disabled);
+    }
+
+    /// Decompress bytes
+    /**
+     * @param buf Byte buffer to decompress
+     * @param len Length of buf
+     * @param out String to append decompressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code decompress(uint8_t const *, size_t, std::string &) {
+        return make_error_code(error::disabled);
+    }
+};
+
+} // namespace permessage_deflate
+} // namespace extensions
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_EXTENSION_PERMESSAGE_DEFLATE_DISABLED_HPP
diff --git a/subprojects/websocketpp/websocketpp/extensions/permessage_deflate/enabled.hpp b/subprojects/websocketpp/websocketpp/extensions/permessage_deflate/enabled.hpp
new file mode 100644
index 000000000..d05403a8a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/extensions/permessage_deflate/enabled.hpp
@@ -0,0 +1,817 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_PROCESSOR_EXTENSION_PERMESSAGEDEFLATE_HPP
+#define WEBSOCKETPP_PROCESSOR_EXTENSION_PERMESSAGEDEFLATE_HPP
+
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/common/platforms.hpp>
+#include <websocketpp/common/stdint.hpp>
+#include <websocketpp/common/system_error.hpp>
+#include <websocketpp/error.hpp>
+
+#include <websocketpp/extensions/extension.hpp>
+
+#include "zlib.h"
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace extensions {
+
+/// Implementation of RFC 7692, the permessage-deflate WebSocket extension
+/**
+ * ### permessage-deflate interface
+ *
+ * **init**\n
+ * `lib::error_code init(bool is_server)`\n
+ * Performs initialization
+ *
+ * **is_implimented**\n
+ * `bool is_implimented()`\n
+ * Returns whether or not the object impliments the extension or not
+ *
+ * **is_enabled**\n
+ * `bool is_enabled()`\n
+ * Returns whether or not the extension was negotiated for the current
+ * connection
+ *
+ * **generate_offer**\n
+ * `std::string generate_offer() const`\n
+ * Create an extension offer string based on local policy
+ *
+ * **validate_response**\n
+ * `lib::error_code validate_response(http::attribute_list const & response)`\n
+ * Negotiate the parameters of extension use
+ *
+ * **negotiate**\n
+ * `err_str_pair negotiate(http::attribute_list const & attributes)`\n
+ * Negotiate the parameters of extension use
+ *
+ * **compress**\n
+ * `lib::error_code compress(std::string const & in, std::string & out)`\n
+ * Compress the bytes in `in` and append them to `out`
+ *
+ * **decompress**\n
+ * `lib::error_code decompress(uint8_t const * buf, size_t len, std::string &
+ * out)`\n
+ * Decompress `len` bytes from `buf` and append them to string `out`
+ */
+namespace permessage_deflate {
+
+/// Permessage deflate error values
+namespace error {
+enum value {
+    /// Catch all
+    general = 1,
+
+    /// Invalid extension attributes
+    invalid_attributes,
+
+    /// Invalid extension attribute value
+    invalid_attribute_value,
+
+    /// Invalid megotiation mode
+    invalid_mode,
+
+    /// Unsupported extension attributes
+    unsupported_attributes,
+
+    /// Invalid value for max_window_bits
+    invalid_max_window_bits,
+
+    /// ZLib Error
+    zlib_error,
+
+    /// Uninitialized
+    uninitialized,
+};
+
+/// Permessage-deflate error category
+class category : public lib::error_category {
+public:
+    category() {}
+
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.extension.permessage-deflate";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case general:
+                return "Generic permessage-compress error";
+            case invalid_attributes:
+                return "Invalid extension attributes";
+            case invalid_attribute_value:
+                return "Invalid extension attribute value";
+            case invalid_mode:
+                return "Invalid permessage-deflate negotiation mode";
+            case unsupported_attributes:
+                return "Unsupported extension attributes";
+            case invalid_max_window_bits:
+                return "Invalid value for max_window_bits";
+            case zlib_error:
+                return "A zlib function returned an error";
+            case uninitialized:
+                return "Deflate extension must be initialized before use";
+            default:
+                return "Unknown permessage-compress error";
+        }
+    }
+};
+
+/// Get a reference to a static copy of the permessage-deflate error category
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+/// Create an error code in the permessage-deflate category
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace permessage_deflate
+} // namespace extensions
+} // namespace websocketpp
+
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum
+    <websocketpp::extensions::permessage_deflate::error::value>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+namespace websocketpp {
+namespace extensions {
+namespace permessage_deflate {
+
+/// Default value for server_max_window_bits as defined by RFC 7692
+static uint8_t const default_server_max_window_bits = 15;
+/// Minimum value for server_max_window_bits as defined by RFC 7692
+/**
+ * NOTE: A value of 8 is not actually supported by zlib, the deflate
+ * library that WebSocket++ uses. To preserve backwards compatibility
+ * with RFC 7692 and previous versions of the library a value of 8
+ * is accepted by the library but will always be negotiated as 9.
+ */
+static uint8_t const min_server_max_window_bits = 8;
+/// Maximum value for server_max_window_bits as defined by RFC 7692
+static uint8_t const max_server_max_window_bits = 15;
+
+/// Default value for client_max_window_bits as defined by RFC 7692
+static uint8_t const default_client_max_window_bits = 15;
+/// Minimum value for client_max_window_bits as defined by RFC 7692
+/**
+ * NOTE: A value of 8 is not actually supported by zlib, the deflate
+ * library that WebSocket++ uses. To preserve backwards compatibility
+ * with RFC 7692 and previous versions of the library a value of 8
+ * is accepted by the library but will always be negotiated as 9.
+ */
+static uint8_t const min_client_max_window_bits = 8;
+/// Maximum value for client_max_window_bits as defined by RFC 7692
+static uint8_t const max_client_max_window_bits = 15;
+
+namespace mode {
+enum value {
+    /// Accept any value the remote endpoint offers
+    accept = 1,
+    /// Decline any value the remote endpoint offers. Insist on defaults.
+    decline,
+    /// Use the largest value common to both offers
+    largest,
+    /// Use the smallest value common to both offers
+    smallest
+};
+} // namespace mode
+
+template <typename config>
+class enabled {
+public:
+    enabled()
+      : m_enabled(false)
+      , m_server_no_context_takeover(false)
+      , m_client_no_context_takeover(false)
+      , m_server_max_window_bits(15)
+      , m_client_max_window_bits(15)
+      , m_server_max_window_bits_mode(mode::accept)
+      , m_client_max_window_bits_mode(mode::accept)
+      , m_initialized(false)
+      , m_compress_buffer_size(8192)
+    {
+        m_dstate.zalloc = Z_NULL;
+        m_dstate.zfree = Z_NULL;
+        m_dstate.opaque = Z_NULL;
+
+        m_istate.zalloc = Z_NULL;
+        m_istate.zfree = Z_NULL;
+        m_istate.opaque = Z_NULL;
+        m_istate.avail_in = 0;
+        m_istate.next_in = Z_NULL;
+    }
+
+    ~enabled() {
+        if (!m_initialized) {
+            return;
+        }
+
+        int ret = deflateEnd(&m_dstate);
+
+        if (ret != Z_OK) {
+            //std::cout << "error cleaning up zlib compression state"
+            //          << std::endl;
+        }
+
+        ret = inflateEnd(&m_istate);
+
+        if (ret != Z_OK) {
+            //std::cout << "error cleaning up zlib decompression state"
+            //          << std::endl;
+        }
+    }
+
+    /// Initialize zlib state
+    /**
+     * Note: this should be called *after* the negotiation methods. It will use
+     * information from the negotiation to determine how to initialize the zlib
+     * data structures.
+     *
+     * @todo memory level, strategy, etc are hardcoded
+     *
+     * @param is_server True to initialize as a server, false for a client.
+     * @return A code representing the error that occurred, if any
+     */
+    lib::error_code init(bool is_server) {
+        uint8_t deflate_bits;
+        uint8_t inflate_bits;
+
+        if (is_server) {
+            deflate_bits = m_server_max_window_bits;
+            inflate_bits = m_client_max_window_bits;
+        } else {
+            deflate_bits = m_client_max_window_bits;
+            inflate_bits = m_server_max_window_bits;
+        }
+
+        int ret = deflateInit2(
+            &m_dstate,
+            Z_DEFAULT_COMPRESSION,
+            Z_DEFLATED,
+            -1*deflate_bits,
+            4, // memory level 1-9
+            Z_DEFAULT_STRATEGY
+        );
+
+        if (ret != Z_OK) {
+            return make_error_code(error::zlib_error);
+        }
+
+        ret = inflateInit2(
+            &m_istate,
+            -1*inflate_bits
+        );
+
+        if (ret != Z_OK) {
+            return make_error_code(error::zlib_error);
+        }
+
+        m_compress_buffer.reset(new unsigned char[m_compress_buffer_size]);
+        m_decompress_buffer.reset(new unsigned char[m_compress_buffer_size]);
+        if ((m_server_no_context_takeover && is_server) ||
+            (m_client_no_context_takeover && !is_server))
+        {
+            m_flush = Z_FULL_FLUSH;
+        } else {
+            m_flush = Z_SYNC_FLUSH;
+        }
+        m_initialized = true;
+        return lib::error_code();
+    }
+
+    /// Test if this object implements the permessage-deflate specification
+    /**
+     * Because this object does implieent it, it will always return true.
+     *
+     * @return Whether or not this object implements permessage-deflate
+     */
+    bool is_implemented() const {
+        return true;
+    }
+
+    /// Test if the extension was negotiated for this connection
+    /**
+     * Retrieves whether or not this extension is in use based on the initial
+     * handshake extension negotiations.
+     *
+     * @return Whether or not the extension is in use
+     */
+    bool is_enabled() const {
+        return m_enabled;
+    }
+
+    /// Reset server's outgoing LZ77 sliding window for each new message
+    /**
+     * Enabling this setting will cause the server's compressor to reset the
+     * compression state (the LZ77 sliding window) for every message. This
+     * means that the compressor will not look back to patterns in previous
+     * messages to improve compression. This will reduce the compression
+     * efficiency for large messages somewhat and small messages drastically.
+     *
+     * This option may reduce server compressor memory usage and client
+     * decompressor memory usage.
+     * @todo Document to what extent memory usage will be reduced
+     *
+     * For clients, this option is dependent on server support. Enabling it
+     * via this method does not guarantee that it will be successfully
+     * negotiated, only that it will be requested.
+     *
+     * For servers, no client support is required. Enabling this option on a
+     * server will result in its use. The server will signal to clients that
+     * the option will be in use so they can optimize resource usage if they
+     * are able.
+     */
+    void enable_server_no_context_takeover() {
+        m_server_no_context_takeover = true;
+    }
+
+    /// Reset client's outgoing LZ77 sliding window for each new message
+    /**
+     * Enabling this setting will cause the client's compressor to reset the
+     * compression state (the LZ77 sliding window) for every message. This
+     * means that the compressor will not look back to patterns in previous
+     * messages to improve compression. This will reduce the compression
+     * efficiency for large messages somewhat and small messages drastically.
+     *
+     * This option may reduce client compressor memory usage and server
+     * decompressor memory usage.
+     * @todo Document to what extent memory usage will be reduced
+     *
+     * This option is supported by all compliant clients and servers. Enabling
+     * it via either endpoint should be sufficient to ensure it is used.
+     */
+    void enable_client_no_context_takeover() {
+        m_client_no_context_takeover = true;
+    }
+
+    /// Limit server LZ77 sliding window size
+    /**
+     * The bits setting is the base 2 logarithm of the maximum window size that
+     * the server must use to compress outgoing messages. The permitted range
+     * is 9 to 15 inclusive. 9 represents a 512 byte window and 15 a 32KiB
+     * window. The default setting is 15.
+     *
+     * Mode Options:
+     * - accept: Accept whatever the remote endpoint offers.
+     * - decline: Decline any offers to deviate from the defaults
+     * - largest: Accept largest window size acceptable to both endpoints
+     * - smallest: Accept smallest window size acceptiable to both endpoints
+     *
+     * This setting is dependent on server support. A client requesting this
+     * setting may be rejected by the server or have the exact value used
+     * adjusted by the server. A server may unilaterally set this value without
+     * client support.
+     *
+     * NOTE: The permessage-deflate spec specifies that a value of 8 is allowed.
+     * Prior to version 0.8.0 a value of 8 was also allowed by this library.
+     * zlib, the deflate compression library that WebSocket++ uses has always
+     * silently adjusted a value of 8 to 9. In recent versions of zlib (1.2.9 
+     * and greater) a value of 8 is now explicitly rejected. WebSocket++ 0.8.0
+     * continues to perform the 8->9 conversion for backwards compatibility
+     * purposes but this should be considered deprecated functionality.
+     *
+     * @param bits The size to request for the outgoing window size
+     * @param mode The mode to use for negotiating this parameter
+     * @return A status code
+     */
+    lib::error_code set_server_max_window_bits(uint8_t bits, mode::value mode) {
+        if (bits < min_server_max_window_bits || bits > max_server_max_window_bits) {
+            return error::make_error_code(error::invalid_max_window_bits);
+        }
+
+        // See note in doc comment above about what is happening here
+        if (bits == 8) {
+            bits = 9;
+        }
+
+        m_server_max_window_bits = bits;
+        m_server_max_window_bits_mode = mode;
+
+        return lib::error_code();
+    }
+
+    /// Limit client LZ77 sliding window size
+    /**
+     * The bits setting is the base 2 logarithm of the window size that the
+     * client must use to compress outgoing messages. The permitted range is 9
+     * to 15 inclusive. 9 represents a 512 byte window and 15 a 32KiB window.
+     * The default setting is 15.
+     *
+     * Mode Options:
+     * - accept: Accept whatever the remote endpoint offers.
+     * - decline: Decline any offers to deviate from the defaults
+     * - largest: Accept largest window size acceptable to both endpoints
+     * - smallest: Accept smallest window size acceptiable to both endpoints
+     *
+     * This setting is dependent on client support. A client may limit its own
+     * outgoing window size unilaterally. A server may only limit the client's
+     * window size if the remote client supports that feature.
+     *
+     * NOTE: The permessage-deflate spec specifies that a value of 8 is allowed.
+     * Prior to version 0.8.0 a value of 8 was also allowed by this library.
+     * zlib, the deflate compression library that WebSocket++ uses has always
+     * silently adjusted a value of 8 to 9. In recent versions of zlib (1.2.9 
+     * and greater) a value of 8 is now explicitly rejected. WebSocket++ 0.8.0
+     * continues to perform the 8->9 conversion for backwards compatibility
+     * purposes but this should be considered deprecated functionality.
+     *
+     * @param bits The size to request for the outgoing window size
+     * @param mode The mode to use for negotiating this parameter
+     * @return A status code
+     */
+    lib::error_code set_client_max_window_bits(uint8_t bits, mode::value mode) {
+        if (bits < min_client_max_window_bits || bits > max_client_max_window_bits) {
+            return error::make_error_code(error::invalid_max_window_bits);
+        }
+
+        // See note in doc comment above about what is happening here
+        if (bits == 8) {
+            bits = 9;
+        }
+
+        m_client_max_window_bits = bits;
+        m_client_max_window_bits_mode = mode;
+
+        return lib::error_code();
+    }
+
+    /// Generate extension offer
+    /**
+     * Creates an offer string to include in the Sec-WebSocket-Extensions
+     * header of outgoing client requests.
+     *
+     * @return A WebSocket extension offer string for this extension
+     */
+    std::string generate_offer() const {
+        // TODO: this should be dynamically generated based on user settings
+        return "permessage-deflate; client_no_context_takeover; client_max_window_bits";
+    }
+
+    /// Validate extension response
+    /**
+     * Confirm that the server has negotiated settings compatible with our
+     * original offer and apply those settings to the extension state.
+     *
+     * @param response The server response attribute list to validate
+     * @return Validation error or 0 on success
+     */
+    lib::error_code validate_offer(http::attribute_list const &) {
+        return lib::error_code();
+    }
+
+    /// Negotiate extension
+    /**
+     * Confirm that the client's extension negotiation offer has settings
+     * compatible with local policy. If so, generate a reply and apply those
+     * settings to the extension state.
+     *
+     * @param offer Attribute from client's offer
+     * @return Status code and value to return to remote endpoint
+     */
+    err_str_pair negotiate(http::attribute_list const & offer) {
+        err_str_pair ret;
+
+        http::attribute_list::const_iterator it;
+        for (it = offer.begin(); it != offer.end(); ++it) {
+            if (it->first == "server_no_context_takeover") {
+                negotiate_server_no_context_takeover(it->second,ret.first);
+            } else if (it->first == "client_no_context_takeover") {
+                negotiate_client_no_context_takeover(it->second,ret.first);
+            } else if (it->first == "server_max_window_bits") {
+                negotiate_server_max_window_bits(it->second,ret.first);
+            } else if (it->first == "client_max_window_bits") {
+                negotiate_client_max_window_bits(it->second,ret.first);
+            } else {
+                ret.first = make_error_code(error::invalid_attributes);
+            }
+
+            if (ret.first) {
+                break;
+            }
+        }
+
+        if (ret.first == lib::error_code()) {
+            m_enabled = true;
+            ret.second = generate_response();
+        }
+
+        return ret;
+    }
+
+    /// Compress bytes
+    /**
+     * @todo: avail_in/out is 32 bit, need to fix for cases of >32 bit frames
+     * on 64 bit machines.
+     *
+     * @param [in] in String to compress
+     * @param [out] out String to append compressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code compress(std::string const & in, std::string & out) {
+        if (!m_initialized) {
+            return make_error_code(error::uninitialized);
+        }
+
+        size_t output;
+
+        if (in.empty()) {
+            uint8_t buf[6] = {0x02, 0x00, 0x00, 0x00, 0xff, 0xff};
+            out.append((char *)(buf),6);
+            return lib::error_code();
+        }
+
+        m_dstate.avail_in = in.size();
+        m_dstate.next_in = (unsigned char *)(const_cast<char *>(in.data()));
+
+        do {
+            // Output to local buffer
+            m_dstate.avail_out = m_compress_buffer_size;
+            m_dstate.next_out = m_compress_buffer.get();
+
+            deflate(&m_dstate, m_flush);
+
+            output = m_compress_buffer_size - m_dstate.avail_out;
+
+            out.append((char *)(m_compress_buffer.get()),output);
+        } while (m_dstate.avail_out == 0);
+
+        return lib::error_code();
+    }
+
+    /// Decompress bytes
+    /**
+     * @param buf Byte buffer to decompress
+     * @param len Length of buf
+     * @param out String to append decompressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code decompress(uint8_t const * buf, size_t len, std::string &
+        out)
+    {
+        if (!m_initialized) {
+            return make_error_code(error::uninitialized);
+        }
+
+        int ret;
+
+        m_istate.avail_in = len;
+        m_istate.next_in = const_cast<unsigned char *>(buf);
+
+        do {
+            m_istate.avail_out = m_compress_buffer_size;
+            m_istate.next_out = m_decompress_buffer.get();
+
+            ret = inflate(&m_istate, Z_SYNC_FLUSH);
+
+            if (ret == Z_NEED_DICT || ret == Z_DATA_ERROR || ret == Z_MEM_ERROR) {
+                return make_error_code(error::zlib_error);
+            }
+
+            out.append(
+                reinterpret_cast<char *>(m_decompress_buffer.get()),
+                m_compress_buffer_size - m_istate.avail_out
+            );
+        } while (m_istate.avail_out == 0);
+
+        return lib::error_code();
+    }
+private:
+    /// Generate negotiation response
+    /**
+     * @return Generate extension negotiation reponse string to send to client
+     */
+    std::string generate_response() {
+        std::string ret = "permessage-deflate";
+
+        if (m_server_no_context_takeover) {
+            ret += "; server_no_context_takeover";
+        }
+
+        if (m_client_no_context_takeover) {
+            ret += "; client_no_context_takeover";
+        }
+
+        if (m_server_max_window_bits < default_server_max_window_bits) {
+            std::stringstream s;
+            s << int(m_server_max_window_bits);
+            ret += "; server_max_window_bits="+s.str();
+        }
+
+        if (m_client_max_window_bits < default_client_max_window_bits) {
+            std::stringstream s;
+            s << int(m_client_max_window_bits);
+            ret += "; client_max_window_bits="+s.str();
+        }
+
+        return ret;
+    }
+
+    /// Negotiate server_no_context_takeover attribute
+    /**
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_server_no_context_takeover(std::string const & value,
+        lib::error_code & ec)
+    {
+        if (!value.empty()) {
+            ec = make_error_code(error::invalid_attribute_value);
+            return;
+        }
+
+        m_server_no_context_takeover = true;
+    }
+
+    /// Negotiate client_no_context_takeover attribute
+    /**
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_client_no_context_takeover(std::string const & value,
+        lib::error_code & ec)
+    {
+        if (!value.empty()) {
+            ec = make_error_code(error::invalid_attribute_value);
+            return;
+        }
+
+        m_client_no_context_takeover = true;
+    }
+
+    /// Negotiate server_max_window_bits attribute
+    /**
+     * When this method starts, m_server_max_window_bits will contain the server's
+     * preferred value and m_server_max_window_bits_mode will contain the mode the
+     * server wants to use to for negotiation. `value` contains the value the
+     * client requested that we use.
+     *
+     * options:
+     * - decline (ignore value, offer our default instead)
+     * - accept (use the value requested by the client)
+     * - largest (use largest value acceptable to both)
+     * - smallest (use smallest possible value)
+     *
+     * NOTE: As a value of 8 is no longer explicitly supported by zlib but might
+     * be requested for negotiation by an older client/server, if the result of
+     * the negotiation would be to send a value of 8, a value of 9 is offered
+     * instead. This ensures that WebSocket++ will only ever negotiate connections
+     * with compression settings explicitly supported by zlib.
+     *
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_server_max_window_bits(std::string const & value,
+        lib::error_code & ec)
+    {
+        uint8_t bits = uint8_t(atoi(value.c_str()));
+
+        if (bits < min_server_max_window_bits || bits > max_server_max_window_bits) {
+            ec = make_error_code(error::invalid_attribute_value);
+            m_server_max_window_bits = default_server_max_window_bits;
+            return;
+        }
+
+        switch (m_server_max_window_bits_mode) {
+            case mode::decline:
+                m_server_max_window_bits = default_server_max_window_bits;
+                break;
+            case mode::accept:
+                m_server_max_window_bits = bits;
+                break;
+            case mode::largest:
+                m_server_max_window_bits = std::min(bits,m_server_max_window_bits);
+                break;
+            case mode::smallest:
+                m_server_max_window_bits = min_server_max_window_bits;
+                break;
+            default:
+                ec = make_error_code(error::invalid_mode);
+                m_server_max_window_bits = default_server_max_window_bits;
+        }
+
+        // See note in doc comment
+        if (m_server_max_window_bits == 8) {
+            m_server_max_window_bits = 9;
+        }
+    }
+
+    /// Negotiate client_max_window_bits attribute
+    /**
+     * When this method starts, m_client_max_window_bits and m_c2s_max_window_mode
+     * will contain the server's preferred values for window size and
+     * negotiation mode.
+     *
+     * options:
+     * - decline (ignore value, offer our default instead)
+     * - accept (use the value requested by the client)
+     * - largest (use largest value acceptable to both)
+     * - smallest (use smallest possible value)
+     *
+     * NOTE: As a value of 8 is no longer explicitly supported by zlib but might
+     * be requested for negotiation by an older client/server, if the result of
+     * the negotiation would be to send a value of 8, a value of 9 is offered
+     * instead. This ensures that WebSocket++ will only ever negotiate connections
+     * with compression settings explicitly supported by zlib.
+     *
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_client_max_window_bits(std::string const & value,
+            lib::error_code & ec)
+    {
+        uint8_t bits = uint8_t(atoi(value.c_str()));
+
+        if (value.empty()) {
+            bits = default_client_max_window_bits;
+        } else if (bits < min_client_max_window_bits ||
+                   bits > max_client_max_window_bits)
+        {
+            ec = make_error_code(error::invalid_attribute_value);
+            m_client_max_window_bits = default_client_max_window_bits;
+            return;
+        }
+
+        switch (m_client_max_window_bits_mode) {
+            case mode::decline:
+                m_client_max_window_bits = default_client_max_window_bits;
+                break;
+            case mode::accept:
+                m_client_max_window_bits = bits;
+                break;
+            case mode::largest:
+                m_client_max_window_bits = std::min(bits,m_client_max_window_bits);
+                break;
+            case mode::smallest:
+                m_client_max_window_bits = min_client_max_window_bits;
+                break;
+            default:
+                ec = make_error_code(error::invalid_mode);
+                m_client_max_window_bits = default_client_max_window_bits;
+        }
+
+        // See note in doc comment
+        if (m_client_max_window_bits == 8) {
+            m_client_max_window_bits = 9;
+        }
+    }
+
+    bool m_enabled;
+    bool m_server_no_context_takeover;
+    bool m_client_no_context_takeover;
+    uint8_t m_server_max_window_bits;
+    uint8_t m_client_max_window_bits;
+    mode::value m_server_max_window_bits_mode;
+    mode::value m_client_max_window_bits_mode;
+
+    bool m_initialized;
+    int m_flush;
+    size_t m_compress_buffer_size;
+    lib::unique_ptr_uchar_array m_compress_buffer;
+    lib::unique_ptr_uchar_array m_decompress_buffer;
+    z_stream m_dstate;
+    z_stream m_istate;
+};
+
+} // namespace permessage_deflate
+} // namespace extensions
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_PROCESSOR_EXTENSION_PERMESSAGEDEFLATE_HPP
diff --git a/subprojects/websocketpp/websocketpp/frame.hpp b/subprojects/websocketpp/websocketpp/frame.hpp
new file mode 100644
index 000000000..18a990b36
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/frame.hpp
@@ -0,0 +1,864 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_FRAME_HPP
+#define WEBSOCKETPP_FRAME_HPP
+
+#include <algorithm>
+#include <string>
+
+#include <websocketpp/common/system_error.hpp>
+#include <websocketpp/common/network.hpp>
+
+#include <websocketpp/utilities.hpp>
+
+namespace websocketpp {
+/// Data structures and utility functions for manipulating WebSocket frames
+/**
+ * namespace frame provides a number of data structures and utility functions
+ * for reading, writing, and manipulating binary encoded WebSocket frames.
+ */
+namespace frame {
+
+/// Minimum length of a WebSocket frame header.
+static unsigned int const BASIC_HEADER_LENGTH = 2;
+/// Maximum length of a WebSocket header
+static unsigned int const MAX_HEADER_LENGTH = 14;
+/// Maximum length of the variable portion of the WebSocket header
+static unsigned int const MAX_EXTENDED_HEADER_LENGTH = 12;
+
+/// Two byte conversion union
+union uint16_converter {
+    uint16_t i;
+    uint8_t  c[2];
+};
+
+/// Four byte conversion union
+union uint32_converter {
+    uint32_t i;
+    uint8_t c[4];
+};
+
+/// Eight byte conversion union
+union uint64_converter {
+    uint64_t i;
+    uint8_t  c[8];
+};
+
+/// Constants and utility functions related to WebSocket opcodes
+/**
+ * WebSocket Opcodes are 4 bits. See RFC6455 section 5.2.
+ */
+namespace opcode {
+    enum value {
+        continuation = 0x0,
+        text = 0x1,
+        binary = 0x2,
+        rsv3 = 0x3,
+        rsv4 = 0x4,
+        rsv5 = 0x5,
+        rsv6 = 0x6,
+        rsv7 = 0x7,
+        close = 0x8,
+        ping = 0x9,
+        pong = 0xA,
+        control_rsvb = 0xB,
+        control_rsvc = 0xC,
+        control_rsvd = 0xD,
+        control_rsve = 0xE,
+        control_rsvf = 0xF,
+
+        CONTINUATION = 0x0,
+        TEXT = 0x1,
+        BINARY = 0x2,
+        RSV3 = 0x3,
+        RSV4 = 0x4,
+        RSV5 = 0x5,
+        RSV6 = 0x6,
+        RSV7 = 0x7,
+        CLOSE = 0x8,
+        PING = 0x9,
+        PONG = 0xA,
+        CONTROL_RSVB = 0xB,
+        CONTROL_RSVC = 0xC,
+        CONTROL_RSVD = 0xD,
+        CONTROL_RSVE = 0xE,
+        CONTROL_RSVF = 0xF
+    };
+
+    /// Check if an opcode is reserved
+    /**
+     * @param v The opcode to test.
+     * @return Whether or not the opcode is reserved.
+     */
+    inline bool reserved(value v) {
+        return (v >= rsv3 && v <= rsv7) ||
+               (v >= control_rsvb && v <= control_rsvf);
+    }
+
+    /// Check if an opcode is invalid
+    /**
+     * Invalid opcodes are negative or require greater than 4 bits to store.
+     *
+     * @param v The opcode to test.
+     * @return Whether or not the opcode is invalid.
+     */
+    inline bool invalid(value v) {
+        return (v > 0xF || v < 0);
+    }
+
+    /// Check if an opcode is for a control frame
+    /**
+     * @param v The opcode to test.
+     * @return Whether or not the opcode is a control opcode.
+     */
+    inline bool is_control(value v) {
+        return v >= 0x8;
+    }
+}
+
+/// Constants related to frame and payload limits
+namespace limits {
+    /// Minimum length of a WebSocket frame header.
+    static unsigned int const basic_header_length = 2;
+
+    /// Maximum length of a WebSocket header
+    static unsigned int const max_header_length = 14;
+
+    /// Maximum length of the variable portion of the WebSocket header
+    static unsigned int const max_extended_header_length = 12;
+
+    /// Maximum size of a basic WebSocket payload
+    static uint8_t const payload_size_basic = 125;
+
+    /// Maximum size of an extended WebSocket payload (basic payload = 126)
+    static uint16_t const payload_size_extended = 0xFFFF; // 2^16, 65535
+
+    /// Maximum size of a jumbo WebSocket payload (basic payload = 127)
+    static uint64_t const payload_size_jumbo = 0x7FFFFFFFFFFFFFFFLL;//2^63
+
+    /// Maximum size of close frame reason
+    /**
+     * This is payload_size_basic - 2 bytes (as first two bytes are used for
+     * the close code
+     */
+    static uint8_t const close_reason_size = 123;
+}
+
+
+// masks for fields in the basic header
+static uint8_t const BHB0_OPCODE = 0x0F;
+static uint8_t const BHB0_RSV3 = 0x10;
+static uint8_t const BHB0_RSV2 = 0x20;
+static uint8_t const BHB0_RSV1 = 0x40;
+static uint8_t const BHB0_FIN = 0x80;
+
+static uint8_t const BHB1_PAYLOAD = 0x7F;
+static uint8_t const BHB1_MASK = 0x80;
+
+static uint8_t const payload_size_code_16bit = 0x7E; // 126
+static uint8_t const payload_size_code_64bit = 0x7F; // 127
+
+typedef uint32_converter masking_key_type;
+
+/// The constant size component of a WebSocket frame header
+struct basic_header {
+    basic_header() : b0(0x00),b1(0x00) {}
+
+    basic_header(uint8_t p0, uint8_t p1) : b0(p0), b1(p1) {}
+
+    basic_header(opcode::value op, uint64_t size, bool fin, bool mask,
+        bool rsv1 = false, bool rsv2 = false, bool rsv3 = false) : b0(0x00),
+        b1(0x00)
+    {
+        if (fin) {
+            b0 |= BHB0_FIN;
+        }
+        if (rsv1) {
+            b0 |= BHB0_RSV1;
+        }
+        if (rsv2) {
+            b0 |= BHB0_RSV2;
+        }
+        if (rsv3) {
+            b0 |= BHB0_RSV3;
+        }
+        b0 |= (op & BHB0_OPCODE);
+
+        if (mask) {
+            b1 |= BHB1_MASK;
+        }
+
+        uint8_t basic_value;
+
+        if (size <= limits::payload_size_basic) {
+            basic_value = static_cast<uint8_t>(size);
+        } else if (size <= limits::payload_size_extended) {
+            basic_value = payload_size_code_16bit;
+        } else {
+            basic_value = payload_size_code_64bit;
+        }
+
+
+        b1 |= basic_value;
+    }
+
+    uint8_t b0;
+    uint8_t b1;
+};
+
+/// The variable size component of a WebSocket frame header
+struct extended_header {
+    extended_header() {
+        std::fill_n(this->bytes,MAX_EXTENDED_HEADER_LENGTH,0x00);
+    }
+
+    extended_header(uint64_t payload_size) {
+        std::fill_n(this->bytes,MAX_EXTENDED_HEADER_LENGTH,0x00);
+
+        copy_payload(payload_size);
+    }
+
+    extended_header(uint64_t payload_size, uint32_t masking_key) {
+        std::fill_n(this->bytes,MAX_EXTENDED_HEADER_LENGTH,0x00);
+
+        // Copy payload size
+        int offset = copy_payload(payload_size);
+
+        // Copy Masking Key
+        uint32_converter temp32;
+        temp32.i = masking_key;
+        std::copy(temp32.c,temp32.c+4,bytes+offset);
+    }
+
+    uint8_t bytes[MAX_EXTENDED_HEADER_LENGTH];
+private:
+    int copy_payload(uint64_t payload_size) {
+        int payload_offset = 0;
+
+        if (payload_size <= limits::payload_size_basic) {
+            payload_offset = 8;
+        } else if (payload_size <= limits::payload_size_extended) {
+            payload_offset = 6;
+        }
+
+        uint64_converter temp64;
+        temp64.i = lib::net::_htonll(payload_size);
+        std::copy(temp64.c+payload_offset,temp64.c+8,bytes);
+
+        return 8-payload_offset;
+    }
+};
+
+bool get_fin(basic_header const &h);
+void set_fin(basic_header &h, bool value);
+bool get_rsv1(basic_header const &h);
+void set_rsv1(basic_header &h, bool value);
+bool get_rsv2(basic_header const &h);
+void set_rsv2(basic_header &h, bool value);
+bool get_rsv3(basic_header const &h);
+void set_rsv3(basic_header &h, bool value);
+opcode::value get_opcode(basic_header const &h);
+bool get_masked(basic_header const &h);
+void set_masked(basic_header &h, bool value);
+uint8_t get_basic_size(basic_header const &);
+size_t get_header_len(basic_header const &);
+unsigned int get_masking_key_offset(basic_header const &);
+
+std::string write_header(basic_header const &, extended_header const &);
+masking_key_type get_masking_key(basic_header const &, extended_header const &);
+uint16_t get_extended_size(extended_header const &);
+uint64_t get_jumbo_size(extended_header const &);
+uint64_t get_payload_size(basic_header const &, extended_header const &);
+
+size_t prepare_masking_key(masking_key_type const & key);
+size_t circshift_prepared_key(size_t prepared_key, size_t offset);
+
+// Functions for performing xor based masking and unmasking
+template <typename input_iter, typename output_iter>
+void byte_mask(input_iter b, input_iter e, output_iter o, masking_key_type
+    const & key, size_t key_offset = 0);
+template <typename iter_type>
+void byte_mask(iter_type b, iter_type e, masking_key_type const & key,
+    size_t key_offset = 0);
+void word_mask_exact(uint8_t * input, uint8_t * output, size_t length,
+    masking_key_type const & key);
+void word_mask_exact(uint8_t * data, size_t length, masking_key_type const &
+    key);
+size_t word_mask_circ(uint8_t * input, uint8_t * output, size_t length,
+    size_t prepared_key);
+size_t word_mask_circ(uint8_t * data, size_t length, size_t prepared_key);
+
+/// Check whether the frame's FIN bit is set.
+/**
+ * @param [in] h The basic header to extract from.
+ * @return True if the header's fin bit is set.
+ */
+inline bool get_fin(basic_header const & h) {
+    return ((h.b0 & BHB0_FIN) == BHB0_FIN);
+}
+
+/// Set the frame's FIN bit
+/**
+ * @param [out] h Header to set.
+ * @param [in] value Value to set it to.
+ */
+inline void set_fin(basic_header & h, bool value) {
+    h.b0 = (value ? h.b0 | BHB0_FIN : h.b0 & ~BHB0_FIN);
+}
+
+/// check whether the frame's RSV1 bit is set
+/**
+ * @param [in] h The basic header to extract from.
+ * @return True if the header's RSV1 bit is set.
+ */
+inline bool get_rsv1(const basic_header &h) {
+    return ((h.b0 & BHB0_RSV1) == BHB0_RSV1);
+}
+
+/// Set the frame's RSV1 bit
+/**
+ * @param [out] h Header to set.
+ * @param [in] value Value to set it to.
+ */
+inline void set_rsv1(basic_header &h, bool value) {
+    h.b0 = (value ? h.b0 | BHB0_RSV1 : h.b0 & ~BHB0_RSV1);
+}
+
+/// check whether the frame's RSV2 bit is set
+/**
+ * @param [in] h The basic header to extract from.
+ * @return True if the header's RSV2 bit is set.
+ */
+inline bool get_rsv2(const basic_header &h) {
+    return ((h.b0 & BHB0_RSV2) == BHB0_RSV2);
+}
+
+/// Set the frame's RSV2 bit
+/**
+ * @param [out] h Header to set.
+ * @param [in] value Value to set it to.
+ */
+inline void set_rsv2(basic_header &h, bool value) {
+    h.b0 = (value ? h.b0 | BHB0_RSV2 : h.b0 & ~BHB0_RSV2);
+}
+
+/// check whether the frame's RSV3 bit is set
+/**
+ * @param [in] h The basic header to extract from.
+ * @return True if the header's RSV3 bit is set.
+ */
+inline bool get_rsv3(const basic_header &h) {
+    return ((h.b0 & BHB0_RSV3) == BHB0_RSV3);
+}
+
+/// Set the frame's RSV3 bit
+/**
+ * @param [out] h Header to set.
+ * @param [in] value Value to set it to.
+ */
+inline void set_rsv3(basic_header &h, bool value) {
+    h.b0 = (value ? h.b0 | BHB0_RSV3 : h.b0 & ~BHB0_RSV3);
+}
+
+/// Extract opcode from basic header
+/**
+ * @param [in] h The basic header to extract from.
+ * @return The opcode value of the header.
+ */
+inline opcode::value get_opcode(const basic_header &h) {
+    return opcode::value(h.b0 & BHB0_OPCODE);
+}
+
+/// check whether the frame is masked
+/**
+ * @param [in] h The basic header to extract from.
+ * @return True if the header mask bit is set.
+ */
+inline bool get_masked(basic_header const & h) {
+    return ((h.b1 & BHB1_MASK) == BHB1_MASK);
+}
+
+/// Set the frame's MASK bit
+/**
+ * @param [out] h Header to set.
+ * @param value Value to set it to.
+ */
+inline void set_masked(basic_header & h, bool value) {
+    h.b1 = (value ? h.b1 | BHB1_MASK : h.b1 & ~BHB1_MASK);
+}
+
+/// Extracts the raw payload length specified in the basic header
+/**
+ * A basic WebSocket frame header contains a 7 bit value that represents the
+ * payload size. There are two reserved values that are used to indicate that
+ * the actual payload size will not fit in 7 bits and that the full payload
+ * size is included in a separate field. The values are as follows:
+ *
+ * PAYLOAD_SIZE_CODE_16BIT (0x7E) indicates that the actual payload is less
+ * than 16 bit
+ *
+ * PAYLOAD_SIZE_CODE_64BIT (0x7F) indicates that the actual payload is less
+ * than 63 bit
+ *
+ * @param [in] h Basic header to read value from.
+ * @return The exact size encoded in h.
+ */
+inline uint8_t get_basic_size(const basic_header &h) {
+    return h.b1 & BHB1_PAYLOAD;
+}
+
+/// Calculates the full length of the header based on the first bytes.
+/**
+ * A WebSocket frame header always has at least two bytes. Encoded within the
+ * first two bytes is all the information necessary to calculate the full
+ * (variable) header length. get_header_len() calculates the full header
+ * length for the given two byte basic header.
+ *
+ * @param h Basic frame header to extract size from.
+ * @return Full length of the extended header.
+ */
+inline size_t get_header_len(basic_header const & h) {
+    // TODO: check extensions?
+
+    // masking key offset represents the space used for the extended length
+    // fields
+    size_t size = BASIC_HEADER_LENGTH + get_masking_key_offset(h);
+
+    // If the header is masked there is a 4 byte masking key
+    if (get_masked(h)) {
+        size += 4;
+    }
+
+    return size;
+}
+
+/// Calculate the offset location of the masking key within the extended header
+/**
+ * Calculate the offset location of the masking key within the extended header
+ * using information from its corresponding basic header
+ *
+ * @param h Corresponding basic header to calculate from.
+ *
+ * @return byte offset of the first byte of the masking key
+ */
+inline unsigned int get_masking_key_offset(const basic_header &h) {
+    if (get_basic_size(h) == payload_size_code_16bit) {
+        return 2;
+    } else if (get_basic_size(h) == payload_size_code_64bit) {
+        return 8;
+    } else {
+        return 0;
+    }
+}
+
+/// Generate a properly sized contiguous string that encodes a full frame header
+/**
+ * Copy the basic header h and extended header e into a properly sized
+ * contiguous frame header string for the purposes of writing out to the wire.
+ *
+ * @param h The basic header to include
+ * @param e The extended header to include
+ *
+ * @return A contiguous string containing h and e
+ */
+inline std::string prepare_header(const basic_header &h, const
+    extended_header &e)
+{
+    std::string ret;
+
+    ret.push_back(char(h.b0));
+    ret.push_back(char(h.b1));
+    ret.append(
+        reinterpret_cast<const char*>(e.bytes),
+        get_header_len(h)-BASIC_HEADER_LENGTH
+    );
+
+    return ret;
+}
+
+/// Extract the masking key from a frame header
+/**
+ * Note that while read and written as an integer at times, this value is not
+ * an integer and should never be interpreted as one. Big and little endian
+ * machines will generate and store masking keys differently without issue as
+ * long as the integer values remain irrelivant.
+ *
+ * @param h The basic header to extract from
+ * @param e The extended header to extract from
+ *
+ * @return The masking key as an integer.
+ */
+inline masking_key_type get_masking_key(const basic_header &h, const
+    extended_header &e)
+{
+    masking_key_type temp32;
+
+    if (!get_masked(h)) {
+        temp32.i = 0;
+    } else {
+        unsigned int offset = get_masking_key_offset(h);
+        std::copy(e.bytes+offset,e.bytes+offset+4,temp32.c);
+    }
+
+    return temp32;
+}
+
+/// Extract the extended size field from an extended header
+/**
+ * It is the responsibility of the caller to verify that e is a valid extended
+ * header. This function assumes that e contains an extended payload size.
+ *
+ * @param e The extended header to extract from
+ *
+ * @return The size encoded in the extended header in host byte order
+ */
+inline uint16_t get_extended_size(const extended_header &e) {
+    uint16_converter temp16;
+    std::copy(e.bytes,e.bytes+2,temp16.c);
+    return ntohs(temp16.i);
+}
+
+/// Extract the jumbo size field from an extended header
+/**
+ * It is the responsibility of the caller to verify that e is a valid extended
+ * header. This function assumes that e contains a jumbo payload size.
+ *
+ * @param e The extended header to extract from
+ *
+ * @return The size encoded in the extended header in host byte order
+ */
+inline uint64_t get_jumbo_size(const extended_header &e) {
+    uint64_converter temp64;
+    std::copy(e.bytes,e.bytes+8,temp64.c);
+    return lib::net::_ntohll(temp64.i);
+}
+
+/// Extract the full payload size field from a WebSocket header
+/**
+ * It is the responsibility of the caller to verify that h and e together
+ * represent a valid WebSocket frame header. This function assumes only that h
+ * and e are valid. It uses information in the basic header to determine where
+ * to look for the payload_size
+ *
+ * @param h The basic header to extract from
+ * @param e The extended header to extract from
+ *
+ * @return The size encoded in the combined header in host byte order.
+ */
+inline uint64_t get_payload_size(const basic_header &h, const
+    extended_header &e)
+{
+    uint8_t val = get_basic_size(h);
+
+    if (val <= limits::payload_size_basic) {
+        return val;
+    } else if (val == payload_size_code_16bit) {
+        return get_extended_size(e);
+    } else {
+        return get_jumbo_size(e);
+    }
+}
+
+/// Extract a masking key into a value the size of a machine word.
+/**
+ * Machine word size must be 4 or 8.
+ *
+ * @param key Masking key to extract from
+ *
+ * @return prepared key as a machine word
+ */
+inline size_t prepare_masking_key(const masking_key_type& key) {
+    size_t low_bits = static_cast<size_t>(key.i);
+
+    if (sizeof(size_t) == 8) {
+        uint64_t high_bits = static_cast<size_t>(key.i);
+        return static_cast<size_t>((high_bits << 32) | low_bits);
+    } else {
+        return low_bits;
+    }
+}
+
+/// circularly shifts the supplied prepared masking key by offset bytes
+/**
+ * Prepared_key must be the output of prepare_masking_key with the associated
+ * restrictions on the machine word size. offset must be greater than or equal
+ * to zero and less than sizeof(size_t).
+ */
+inline size_t circshift_prepared_key(size_t prepared_key, size_t offset) {
+    if (offset == 0) {
+        return prepared_key;
+    }
+    if (lib::net::is_little_endian()) {
+        size_t temp = prepared_key << (sizeof(size_t)-offset)*8;
+        return (prepared_key >> offset*8) | temp;
+    } else {
+        size_t temp = prepared_key >> (sizeof(size_t)-offset)*8;
+        return (prepared_key << offset*8) | temp;
+    }
+}
+
+/// Byte by byte mask/unmask
+/**
+ * Iterator based byte by byte masking and unmasking for WebSocket payloads.
+ * Performs masking in place using the supplied key offset by the supplied
+ * offset number of bytes.
+ *
+ * This function is simple and can be done in place on input with arbitrary
+ * lengths and does not vary based on machine word size. It is slow.
+ *
+ * @param b Beginning iterator to start masking
+ *
+ * @param e Ending iterator to end masking
+ *
+ * @param o Beginning iterator to store masked results
+ *
+ * @param key 32 bit key to mask with.
+ *
+ * @param key_offset offset value to start masking at.
+ */
+template <typename input_iter, typename output_iter>
+void byte_mask(input_iter first, input_iter last, output_iter result,
+    masking_key_type const & key, size_t key_offset)
+{
+    size_t key_index = key_offset%4;
+    while (first != last) {
+        *result = *first ^ key.c[key_index++];
+        key_index %= 4;
+        ++result;
+        ++first;
+    }
+}
+
+/// Byte by byte mask/unmask (in place)
+/**
+ * Iterator based byte by byte masking and unmasking for WebSocket payloads.
+ * Performs masking in place using the supplied key offset by the supplied
+ * offset number of bytes.
+ *
+ * This function is simple and can be done in place on input with arbitrary
+ * lengths and does not vary based on machine word size. It is slow.
+ *
+ * @param b Beginning iterator to start masking
+ *
+ * @param e Ending iterator to end masking
+ *
+ * @param key 32 bit key to mask with.
+ *
+ * @param key_offset offset value to start masking at.
+ */
+template <typename iter_type>
+void byte_mask(iter_type b, iter_type e, masking_key_type const & key,
+    size_t key_offset)
+{
+    byte_mask(b,e,b,key,key_offset);
+}
+
+/// Exact word aligned mask/unmask
+/**
+ * Balanced combination of byte by byte and circular word by word masking.
+ * Best used to mask complete messages at once. Has much higher setup costs than
+ * word_mask_circ but works with exact sized buffers.
+ *
+ * Buffer based word by word masking and unmasking for WebSocket payloads.
+ * Masking is done in word by word chunks with the remainder not divisible by
+ * the word size done byte by byte.
+ *
+ * input and output must both be at least length bytes. Exactly length bytes
+ * will be written.
+ *
+ * @param input buffer to mask or unmask
+ *
+ * @param output buffer to store the output. May be the same as input.
+ *
+ * @param length length of data buffer
+ *
+ * @param key Masking key to use
+ */
+inline void word_mask_exact(uint8_t* input, uint8_t* output, size_t length,
+    const masking_key_type& key)
+{
+    size_t prepared_key = prepare_masking_key(key);
+    size_t n = length/sizeof(size_t);
+    size_t* input_word = reinterpret_cast<size_t*>(input);
+    size_t* output_word = reinterpret_cast<size_t*>(output);
+
+    for (size_t i = 0; i < n; i++) {
+        output_word[i] = input_word[i] ^ prepared_key;
+    }
+
+    for (size_t i = n*sizeof(size_t); i < length; i++) {
+        output[i] = input[i] ^ key.c[i%4];
+    }
+}
+
+/// Exact word aligned mask/unmask (in place)
+/**
+ * In place version of word_mask_exact
+ *
+ * @see word_mask_exact
+ *
+ * @param data buffer to read and write from
+ *
+ * @param length length of data buffer
+ *
+ * @param key Masking key to use
+ */
+inline void word_mask_exact(uint8_t* data, size_t length, const
+    masking_key_type& key)
+{
+    word_mask_exact(data,data,length,key);
+}
+
+/// Circular word aligned mask/unmask
+/**
+ * Performs a circular mask/unmask in word sized chunks using pre-prepared keys
+ * that store state between calls. Best for providing streaming masking or
+ * unmasking of small chunks at a time of a larger message. Requires that the
+ * underlying allocated size of the data buffer be a multiple of the word size.
+ * Data in the buffer after `length` will be overwritten only with the same
+ * values that were originally present.
+ *
+ * Buffer based word by word masking and unmasking for WebSocket payloads.
+ * Performs masking in place using the supplied key. Casts the data buffer to
+ * an array of size_t's and performs masking word by word. The underlying
+ * buffer size must be a muliple of the word size.
+ *
+ * word_mask returns a copy of prepared_key circularly shifted based on the
+ * length value. The returned value may be fed back into word_mask when more
+ * data is available.
+ *
+ * input and output must both have length at least:
+ *    ceil(length/sizeof(size_t))*sizeof(size_t)
+ * Exactly that many bytes will be written, although only exactly length bytes
+ * will be changed (trailing bytes will be replaced without masking)
+ *
+ * @param data Character buffer to mask
+ *
+ * @param length Length of data
+ *
+ * @param prepared_key Prepared key to use.
+ *
+ * @return the prepared_key shifted to account for the input length
+ */
+inline size_t word_mask_circ(uint8_t * input, uint8_t * output, size_t length,
+    size_t prepared_key)
+{
+    size_t n = length / sizeof(size_t); // whole words
+    size_t l = length - (n * sizeof(size_t)); // remaining bytes
+    size_t * input_word = reinterpret_cast<size_t *>(input);
+    size_t * output_word = reinterpret_cast<size_t *>(output);
+
+    // mask word by word
+    for (size_t i = 0; i < n; i++) {
+        output_word[i] = input_word[i] ^ prepared_key;
+    }
+
+    // mask partial word at the end
+    size_t start = length - l;
+    uint8_t * byte_key = reinterpret_cast<uint8_t *>(&prepared_key);
+    for (size_t i = 0; i < l; ++i) {
+        output[start+i] = input[start+i] ^ byte_key[i];
+    }
+
+    return circshift_prepared_key(prepared_key,l);
+}
+
+/// Circular word aligned mask/unmask (in place)
+/**
+ * In place version of word_mask_circ
+ *
+ * @see word_mask_circ
+ *
+ * @param data Character buffer to read from and write to
+ *
+ * @param length Length of data
+ *
+ * @param prepared_key Prepared key to use.
+ *
+ * @return the prepared_key shifted to account for the input length
+ */
+inline size_t word_mask_circ(uint8_t* data, size_t length, size_t prepared_key){
+    return word_mask_circ(data,data,length,prepared_key);
+}
+
+/// Circular byte aligned mask/unmask
+/**
+ * Performs a circular mask/unmask in byte sized chunks using pre-prepared keys
+ * that store state between calls. Best for providing streaming masking or
+ * unmasking of small chunks at a time of a larger message. Requires that the
+ * underlying allocated size of the data buffer be a multiple of the word size.
+ * Data in the buffer after `length` will be overwritten only with the same
+ * values that were originally present.
+ *
+ * word_mask returns a copy of prepared_key circularly shifted based on the
+ * length value. The returned value may be fed back into byte_mask when more
+ * data is available.
+ *
+ * @param data Character buffer to mask
+ *
+ * @param length Length of data
+ *
+ * @param prepared_key Prepared key to use.
+ *
+ * @return the prepared_key shifted to account for the input length
+ */
+inline size_t byte_mask_circ(uint8_t * input, uint8_t * output, size_t length,
+    size_t prepared_key)
+{
+    uint32_converter key;
+    key.i = prepared_key;
+
+    for (size_t i = 0; i < length; ++i) {
+        output[i] = input[i] ^ key.c[i % 4];
+    }
+
+    return circshift_prepared_key(prepared_key,length % 4);
+}
+
+/// Circular byte aligned mask/unmask (in place)
+/**
+ * In place version of byte_mask_circ
+ *
+ * @see byte_mask_circ
+ *
+ * @param data Character buffer to read from and write to
+ *
+ * @param length Length of data
+ *
+ * @param prepared_key Prepared key to use.
+ *
+ * @return the prepared_key shifted to account for the input length
+ */
+inline size_t byte_mask_circ(uint8_t* data, size_t length, size_t prepared_key){
+    return byte_mask_circ(data,data,length,prepared_key);
+}
+
+} // namespace frame
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_FRAME_HPP
diff --git a/subprojects/websocketpp/websocketpp/http/constants.hpp b/subprojects/websocketpp/websocketpp/http/constants.hpp
new file mode 100644
index 000000000..f946cb317
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/http/constants.hpp
@@ -0,0 +1,308 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef HTTP_CONSTANTS_HPP
+#define HTTP_CONSTANTS_HPP
+
+#include <exception>
+#include <map>
+#include <string>
+#include <vector>
+#include <utility>
+
+namespace websocketpp {
+/// HTTP handling support
+namespace http {
+    /// The type of an HTTP attribute list
+    /**
+     * The attribute list is an unordered key/value map. Encoded attribute
+     * values are delimited by semicolons.
+     */
+    typedef std::map<std::string,std::string> attribute_list;
+
+    /// The type of an HTTP parameter list
+    /**
+     * The parameter list is an ordered pairing of a parameter and its
+     * associated attribute list. Encoded parameter values are delimited by
+     * commas.
+     */
+    typedef std::vector< std::pair<std::string,attribute_list> > parameter_list;
+
+    /// Literal value of the HTTP header delimiter
+    static char const header_delimiter[] = "\r\n";
+
+    /// Literal value of the HTTP header separator
+    static char const header_separator[] = ":";
+
+    /// Literal value of an empty header
+    static std::string const empty_header;
+
+    /// Maximum size in bytes before rejecting an HTTP header as too big.
+    size_t const max_header_size = 16000;
+    
+    /// Default Maximum size in bytes for HTTP message bodies.
+    size_t const max_body_size = 32000000;
+
+    /// Number of bytes to use for temporary istream read buffers
+    size_t const istream_buffer = 512;
+
+    /// invalid HTTP token characters
+    /**
+     * 0x00 - 0x32, 0x7f-0xff
+     * ( ) < > @ , ; : \ " / [ ] ? = { }
+     */
+    static char const header_token[] = {
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 00..0f
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 10..1f
+        0,1,0,1,1,1,1,1,0,0,1,1,0,1,1,0, // 20..2f
+        1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0, // 30..3f
+        0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 40..4f
+        1,1,1,1,1,1,1,1,1,1,1,0,0,0,1,1, // 50..5f
+        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 60..6f
+        1,1,1,1,1,1,1,1,1,1,1,0,1,0,1,0, // 70..7f
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 80..8f
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 90..9f
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // a0..af
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // b0..bf
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // c0..cf
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // d0..df
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // e0..ef
+        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // f0..ff
+    };
+
+    /// Is the character a token
+    inline bool is_token_char(unsigned char c) {
+        return (header_token[c] == 1);
+    }
+
+    /// Is the character a non-token
+    inline bool is_not_token_char(unsigned char c) {
+        return !header_token[c];
+    }
+
+    /// Is the character whitespace
+    /**
+     * whitespace is space (32) or horizontal tab (9)
+     */
+    inline bool is_whitespace_char(unsigned char c) {
+        return (c == 9 || c == 32);
+    }
+
+    /// Is the character non-whitespace
+    inline bool is_not_whitespace_char(unsigned char c) {
+        return (c != 9 && c != 32);
+    }
+
+    /// HTTP Status codes
+    namespace status_code {
+        enum value {
+            uninitialized = 0,
+
+            continue_code = 100,
+            switching_protocols = 101,
+
+            ok = 200,
+            created = 201,
+            accepted = 202,
+            non_authoritative_information = 203,
+            no_content = 204,
+            reset_content = 205,
+            partial_content = 206,
+
+            multiple_choices = 300,
+            moved_permanently = 301,
+            found = 302,
+            see_other = 303,
+            not_modified = 304,
+            use_proxy = 305,
+            temporary_redirect = 307,
+
+            bad_request = 400,
+            unauthorized = 401,
+            payment_required = 402,
+            forbidden = 403,
+            not_found = 404,
+            method_not_allowed = 405,
+            not_acceptable = 406,
+            proxy_authentication_required = 407,
+            request_timeout = 408,
+            conflict = 409,
+            gone = 410,
+            length_required = 411,
+            precondition_failed = 412,
+            request_entity_too_large = 413,
+            request_uri_too_long = 414,
+            unsupported_media_type = 415,
+            request_range_not_satisfiable = 416,
+            expectation_failed = 417,
+            im_a_teapot = 418,
+            upgrade_required = 426,
+            precondition_required = 428,
+            too_many_requests = 429,
+            request_header_fields_too_large = 431,
+
+            internal_server_error = 500,
+            not_implemented = 501,
+            bad_gateway = 502,
+            service_unavailable = 503,
+            gateway_timeout = 504,
+            http_version_not_supported = 505,
+            not_extended = 510,
+            network_authentication_required = 511
+        };
+
+        // TODO: should this be inline?
+        inline std::string get_string(value c) {
+            switch (c) {
+                case uninitialized:
+                    return "Uninitialized";
+                case continue_code:
+                    return "Continue";
+                case switching_protocols:
+                    return "Switching Protocols";
+                case ok:
+                    return "OK";
+                case created:
+                    return "Created";
+                case accepted:
+                    return "Accepted";
+                case non_authoritative_information:
+                    return "Non Authoritative Information";
+                case no_content:
+                    return "No Content";
+                case reset_content:
+                    return "Reset Content";
+                case partial_content:
+                    return "Partial Content";
+                case multiple_choices:
+                    return "Multiple Choices";
+                case moved_permanently:
+                    return "Moved Permanently";
+                case found:
+                    return "Found";
+                case see_other:
+                    return "See Other";
+                case not_modified:
+                    return "Not Modified";
+                case use_proxy:
+                    return "Use Proxy";
+                case temporary_redirect:
+                    return "Temporary Redirect";
+                case bad_request:
+                    return "Bad Request";
+                case unauthorized:
+                    return "Unauthorized";
+                case payment_required:
+                    return "Payment Required";
+                case forbidden:
+                    return "Forbidden";
+                case not_found:
+                    return "Not Found";
+                case method_not_allowed:
+                    return "Method Not Allowed";
+                case not_acceptable:
+                    return "Not Acceptable";
+                case proxy_authentication_required:
+                    return "Proxy Authentication Required";
+                case request_timeout:
+                    return "Request Timeout";
+                case conflict:
+                    return "Conflict";
+                case gone:
+                    return "Gone";
+                case length_required:
+                    return "Length Required";
+                case precondition_failed:
+                    return "Precondition Failed";
+                case request_entity_too_large:
+                    return "Request Entity Too Large";
+                case request_uri_too_long:
+                    return "Request-URI Too Long";
+                case unsupported_media_type:
+                    return "Unsupported Media Type";
+                case request_range_not_satisfiable:
+                    return "Requested Range Not Satisfiable";
+                case expectation_failed:
+                    return "Expectation Failed";
+                case im_a_teapot:
+                    return "I'm a teapot";
+                case upgrade_required:
+                    return "Upgrade Required";
+                case precondition_required:
+                    return "Precondition Required";
+                case too_many_requests:
+                    return "Too Many Requests";
+                case request_header_fields_too_large:
+                    return "Request Header Fields Too Large";
+                case internal_server_error:
+                    return "Internal Server Error";
+                case not_implemented:
+                    return "Not Implemented";
+                case bad_gateway:
+                    return "Bad Gateway";
+                case service_unavailable:
+                    return "Service Unavailable";
+                case gateway_timeout:
+                    return "Gateway Timeout";
+                case http_version_not_supported:
+                    return "HTTP Version Not Supported";
+                case not_extended:
+                    return "Not Extended";
+                case network_authentication_required:
+                    return "Network Authentication Required";
+                default:
+                    return "Unknown";
+            }
+        }
+    }
+
+    class exception : public std::exception {
+    public:
+        exception(const std::string& log_msg,
+                  status_code::value error_code,
+                  const std::string& error_msg = std::string(),
+                  const std::string& body = std::string())
+          : m_msg(log_msg)
+          , m_error_msg(error_msg)
+          , m_body(body)
+          , m_error_code(error_code) {}
+
+        ~exception() throw() {}
+
+        virtual const char* what() const throw() {
+            return m_msg.c_str();
+        }
+
+        std::string         m_msg;
+        std::string         m_error_msg;
+        std::string         m_body;
+        status_code::value  m_error_code;
+    };
+}
+}
+
+#endif // HTTP_CONSTANTS_HPP
diff --git a/subprojects/websocketpp/websocketpp/http/impl/parser.hpp b/subprojects/websocketpp/websocketpp/http/impl/parser.hpp
new file mode 100644
index 000000000..fd24adb5d
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/http/impl/parser.hpp
@@ -0,0 +1,200 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef HTTP_PARSER_IMPL_HPP
+#define HTTP_PARSER_IMPL_HPP
+
+#include <algorithm>
+#include <cstdlib>
+#include <istream>
+#include <sstream>
+#include <string>
+
+namespace websocketpp {
+namespace http {
+namespace parser {
+
+inline void parser::set_version(std::string const & version) {
+    m_version = version;
+}
+
+inline std::string const & parser::get_header(std::string const & key) const {
+    header_list::const_iterator h = m_headers.find(key);
+
+    if (h == m_headers.end()) {
+        return empty_header;
+    } else {
+        return h->second;
+    }
+}
+
+inline bool parser::get_header_as_plist(std::string const & key,
+    parameter_list & out) const
+{
+    header_list::const_iterator it = m_headers.find(key);
+
+    if (it == m_headers.end() || it->second.size() == 0) {
+        return false;
+    }
+
+    return this->parse_parameter_list(it->second,out);
+}
+
+inline void parser::append_header(std::string const & key, std::string const &
+    val)
+{
+    if (std::find_if(key.begin(),key.end(),is_not_token_char) != key.end()) {
+        throw exception("Invalid header name",status_code::bad_request);
+    }
+
+    if (this->get_header(key).empty()) {
+        m_headers[key] = val;
+    } else {
+        m_headers[key] += ", " + val;
+    }
+}
+
+inline void parser::replace_header(std::string const & key, std::string const &
+    val)
+{
+    m_headers[key] = val;
+}
+
+inline void parser::remove_header(std::string const & key) {
+    m_headers.erase(key);
+}
+
+inline void parser::set_body(std::string const & value) {
+    if (value.size() == 0) {
+        remove_header("Content-Length");
+        m_body.clear();
+        return;
+    }
+
+    // TODO: should this method respect the max size? If so how should errors
+    // be indicated?
+
+    std::stringstream len;
+    len << value.size();
+    replace_header("Content-Length", len.str());
+    m_body = value;
+}
+
+inline bool parser::parse_parameter_list(std::string const & in,
+    parameter_list & out) const
+{
+    if (in.size() == 0) {
+        return false;
+    }
+
+    std::string::const_iterator it;
+    it = extract_parameters(in.begin(),in.end(),out);
+    return (it == in.begin());
+}
+
+inline bool parser::prepare_body() {
+    if (!get_header("Content-Length").empty()) {
+        std::string const & cl_header = get_header("Content-Length");
+        char * end;
+        
+        // TODO: not 100% sure what the compatibility of this method is. Also,
+        // I believe this will only work up to 32bit sizes. Is there a need for
+        // > 4GiB HTTP payloads?
+        m_body_bytes_needed = std::strtoul(cl_header.c_str(),&end,10);
+        
+        if (m_body_bytes_needed > m_body_bytes_max) {
+            throw exception("HTTP message body too large",
+                status_code::request_entity_too_large);
+        }
+        
+        m_body_encoding = body_encoding::plain;
+        return true;
+    } else if (get_header("Transfer-Encoding") == "chunked") {
+        // TODO
+        //m_body_encoding = body_encoding::chunked;
+        return false;
+    } else {
+        return false;
+    }
+}
+
+inline size_t parser::process_body(char const * buf, size_t len) {
+    if (m_body_encoding == body_encoding::plain) {
+        size_t processed = (std::min)(m_body_bytes_needed,len);
+        m_body.append(buf,processed);
+        m_body_bytes_needed -= processed;
+        return processed;
+    } else if (m_body_encoding == body_encoding::chunked) {
+        // TODO: 
+        throw exception("Unexpected body encoding",
+            status_code::internal_server_error);
+    } else {
+        throw exception("Unexpected body encoding",
+            status_code::internal_server_error);
+    }
+}
+
+inline void parser::process_header(std::string::iterator begin,
+    std::string::iterator end)
+{
+    std::string::iterator cursor = std::search(
+        begin,
+        end,
+        header_separator,
+        header_separator + sizeof(header_separator) - 1
+    );
+
+    if (cursor == end) {
+        throw exception("Invalid header line",status_code::bad_request);
+    }
+
+    append_header(strip_lws(std::string(begin,cursor)),
+                  strip_lws(std::string(cursor+sizeof(header_separator)-1,end)));
+}
+
+inline header_list const & parser::get_headers() const {
+    return m_headers;
+}
+
+inline std::string parser::raw_headers() const {
+    std::stringstream raw;
+
+    header_list::const_iterator it;
+    for (it = m_headers.begin(); it != m_headers.end(); it++) {
+        raw << it->first << ": " << it->second << "\r\n";
+    }
+
+    return raw.str();
+}
+
+
+
+} // namespace parser
+} // namespace http
+} // namespace websocketpp
+
+#endif // HTTP_PARSER_IMPL_HPP
diff --git a/subprojects/websocketpp/websocketpp/http/impl/request.hpp b/subprojects/websocketpp/websocketpp/http/impl/request.hpp
new file mode 100644
index 000000000..311a620f6
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/http/impl/request.hpp
@@ -0,0 +1,191 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef HTTP_PARSER_REQUEST_IMPL_HPP
+#define HTTP_PARSER_REQUEST_IMPL_HPP
+
+#include <algorithm>
+#include <sstream>
+#include <string>
+
+#include <websocketpp/http/parser.hpp>
+
+namespace websocketpp {
+namespace http {
+namespace parser {
+
+inline size_t request::consume(char const * buf, size_t len) {
+    size_t bytes_processed;
+    
+    if (m_ready) {return 0;}
+    
+    if (m_body_bytes_needed > 0) {
+        bytes_processed = process_body(buf,len);
+        if (body_ready()) {
+            m_ready = true;
+        }
+        return bytes_processed;
+    }
+
+    // copy new header bytes into buffer
+    m_buf->append(buf,len);
+
+    // Search for delimiter in buf. If found read until then. If not read all
+    std::string::iterator begin = m_buf->begin();
+    std::string::iterator end;
+
+    for (;;) {
+        // search for line delimiter
+        end = std::search(
+            begin,
+            m_buf->end(),
+            header_delimiter,
+            header_delimiter+sizeof(header_delimiter)-1
+        );
+        
+        m_header_bytes += (end-begin+sizeof(header_delimiter));
+        
+        if (m_header_bytes > max_header_size) {
+            // exceeded max header size
+            throw exception("Maximum header size exceeded.",
+                status_code::request_header_fields_too_large);
+        }
+
+        if (end == m_buf->end()) {
+            // we are out of bytes. Discard the processed bytes and copy the
+            // remaining unprecessed bytes to the beginning of the buffer
+            std::copy(begin,end,m_buf->begin());
+            m_buf->resize(static_cast<std::string::size_type>(end-begin));
+            m_header_bytes -= m_buf->size();
+
+            return len;
+        }
+
+        //the range [begin,end) now represents a line to be processed.
+        if (end-begin == 0) {
+            // we got a blank line
+            if (m_method.empty() || get_header("Host").empty()) {
+                throw exception("Incomplete Request",status_code::bad_request);
+            }
+
+            bytes_processed = (
+                len - static_cast<std::string::size_type>(m_buf->end()-end)
+                    + sizeof(header_delimiter) - 1
+            );
+
+            // frees memory used temporarily during request parsing
+            m_buf.reset();
+
+            // if this was not an upgrade request and has a content length
+            // continue capturing content-length bytes and expose them as a 
+            // request body.
+            
+            if (prepare_body()) {
+                bytes_processed += process_body(buf+bytes_processed,len-bytes_processed);
+                if (body_ready()) {
+                    m_ready = true;
+                }
+                return bytes_processed;
+            } else {
+                m_ready = true;
+
+                // return number of bytes processed (starting bytes - bytes left)
+                return bytes_processed;
+            }
+        } else {
+            if (m_method.empty()) {
+                this->process(begin,end);
+            } else {
+                this->process_header(begin,end);
+            }
+        }
+
+        begin = end+(sizeof(header_delimiter)-1);
+    }
+}
+
+inline std::string request::raw() const {
+    // TODO: validation. Make sure all required fields have been set?
+    std::stringstream ret;
+
+    ret << m_method << " " << m_uri << " " << get_version() << "\r\n";
+    ret << raw_headers() << "\r\n" << m_body;
+
+    return ret.str();
+}
+
+inline std::string request::raw_head() const {
+    // TODO: validation. Make sure all required fields have been set?
+    std::stringstream ret;
+
+    ret << m_method << " " << m_uri << " " << get_version() << "\r\n";
+    ret << raw_headers() << "\r\n";
+
+    return ret.str();
+}
+
+inline void request::set_method(std::string const & method) {
+    if (std::find_if(method.begin(),method.end(),is_not_token_char) != method.end()) {
+        throw exception("Invalid method token.",status_code::bad_request);
+    }
+
+    m_method = method;
+}
+
+inline void request::set_uri(std::string const & uri) {
+    // TODO: validation?
+    m_uri = uri;
+}
+
+inline void request::process(std::string::iterator begin, std::string::iterator
+    end)
+{
+    std::string::iterator cursor_start = begin;
+    std::string::iterator cursor_end = std::find(begin,end,' ');
+
+    if (cursor_end == end) {
+        throw exception("Invalid request line1",status_code::bad_request);
+    }
+
+    set_method(std::string(cursor_start,cursor_end));
+
+    cursor_start = cursor_end+1;
+    cursor_end = std::find(cursor_start,end,' ');
+
+    if (cursor_end == end) {
+        throw exception("Invalid request line2",status_code::bad_request);
+    }
+
+    set_uri(std::string(cursor_start,cursor_end));
+    set_version(std::string(cursor_end+1,end));
+}
+
+} // namespace parser
+} // namespace http
+} // namespace websocketpp
+
+#endif // HTTP_PARSER_REQUEST_IMPL_HPP
diff --git a/subprojects/websocketpp/websocketpp/http/impl/response.hpp b/subprojects/websocketpp/websocketpp/http/impl/response.hpp
new file mode 100644
index 000000000..4400cda5c
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/http/impl/response.hpp
@@ -0,0 +1,266 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef HTTP_PARSER_RESPONSE_IMPL_HPP
+#define HTTP_PARSER_RESPONSE_IMPL_HPP
+
+#include <algorithm>
+#include <istream>
+#include <sstream>
+#include <string>
+
+#include <websocketpp/http/parser.hpp>
+
+namespace websocketpp {
+namespace http {
+namespace parser {
+
+inline size_t response::consume(char const * buf, size_t len) {
+    if (m_state == DONE) {return 0;}
+
+    if (m_state == BODY) {
+        return this->process_body(buf,len);
+    }
+
+    // copy new header bytes into buffer
+    m_buf->append(buf,len);
+
+    // Search for delimiter in buf. If found read until then. If not read all
+    std::string::iterator begin = m_buf->begin();
+    std::string::iterator end = begin;
+
+
+    for (;;) {
+        // search for delimiter
+        end = std::search(
+            begin,
+            m_buf->end(),
+            header_delimiter,
+            header_delimiter + sizeof(header_delimiter) - 1
+        );
+
+        m_header_bytes += (end-begin+sizeof(header_delimiter));
+        
+        if (m_header_bytes > max_header_size) {
+            // exceeded max header size
+            throw exception("Maximum header size exceeded.",
+                status_code::request_header_fields_too_large);
+        }
+
+        if (end == m_buf->end()) {
+            // we are out of bytes. Discard the processed bytes and copy the
+            // remaining unprecessed bytes to the beginning of the buffer
+            std::copy(begin,end,m_buf->begin());
+            m_buf->resize(static_cast<std::string::size_type>(end-begin));
+
+            m_read += len;
+            m_header_bytes -= m_buf->size();
+
+            return len;
+        }
+
+        //the range [begin,end) now represents a line to be processed.
+
+        if (end-begin == 0) {
+            // we got a blank line
+            if (m_state == RESPONSE_LINE) {
+                throw exception("Incomplete Request",status_code::bad_request);
+            }
+
+            // TODO: grab content-length
+            std::string length = get_header("Content-Length");
+
+            if (length.empty()) {
+                // no content length found, read indefinitely
+                m_read = 0;
+            } else {
+                std::istringstream ss(length);
+
+                if ((ss >> m_read).fail()) {
+                    throw exception("Unable to parse Content-Length header",
+                                    status_code::bad_request);
+                }
+            }
+
+            m_state = BODY;
+
+            // calc header bytes processed (starting bytes - bytes left)
+            size_t read = (
+                len - static_cast<std::string::size_type>(m_buf->end() - end)
+                + sizeof(header_delimiter) - 1
+            );
+
+            // if there were bytes left process them as body bytes
+            if (read < len) {
+                read += this->process_body(buf+read,(len-read));
+            }
+
+            // frees memory used temporarily during header parsing
+            m_buf.reset();
+
+            return read;
+        } else {
+            if (m_state == RESPONSE_LINE) {
+                this->process(begin,end);
+                m_state = HEADERS;
+            } else {
+                this->process_header(begin,end);
+            }
+        }
+
+        begin = end+(sizeof(header_delimiter) - 1);
+    }
+}
+
+inline size_t response::consume(std::istream & s) {
+    char buf[istream_buffer];
+    size_t bytes_read;
+    size_t bytes_processed;
+    size_t total = 0;
+
+    while (s.good()) {
+        s.getline(buf,istream_buffer);
+        bytes_read = static_cast<size_t>(s.gcount());
+
+        if (s.fail() || s.eof()) {
+            bytes_processed = this->consume(buf,bytes_read);
+            total += bytes_processed;
+
+            if (bytes_processed != bytes_read) {
+                // problem
+                break;
+            }
+        } else if (s.bad()) {
+            // problem
+            break;
+        } else {
+            // the delimiting newline was found. Replace the trailing null with
+            // the newline that was discarded, since our raw consume function
+            // expects the newline to be be there.
+            buf[bytes_read-1] = '\n';
+            bytes_processed = this->consume(buf,bytes_read);
+            total += bytes_processed;
+
+            if (bytes_processed != bytes_read) {
+                // problem
+                break;
+            }
+        }
+    }
+
+    return total;
+}
+
+inline std::string response::raw() const {
+    // TODO: validation. Make sure all required fields have been set?
+
+    std::stringstream ret;
+
+    ret << get_version() << " " << m_status_code << " " << m_status_msg;
+    ret << "\r\n" << raw_headers() << "\r\n";
+
+    ret << m_body;
+
+    return ret.str();
+}
+
+inline void response::set_status(status_code::value code) {
+    // TODO: validation?
+    m_status_code = code;
+    m_status_msg = get_string(code);
+}
+
+inline void response::set_status(status_code::value code, std::string const &
+    msg)
+{
+    // TODO: validation?
+    m_status_code = code;
+    m_status_msg = msg;
+}
+
+inline void response::process(std::string::iterator begin,
+    std::string::iterator end)
+{
+    std::string::iterator cursor_start = begin;
+    std::string::iterator cursor_end = std::find(begin,end,' ');
+
+    if (cursor_end == end) {
+        throw exception("Invalid response line",status_code::bad_request);
+    }
+
+    set_version(std::string(cursor_start,cursor_end));
+
+    cursor_start = cursor_end+1;
+    cursor_end = std::find(cursor_start,end,' ');
+
+    if (cursor_end == end) {
+        throw exception("Invalid request line",status_code::bad_request);
+    }
+
+    int code;
+
+    std::istringstream ss(std::string(cursor_start,cursor_end));
+
+    if ((ss >> code).fail()) {
+        throw exception("Unable to parse response code",status_code::bad_request);
+    }
+
+    set_status(status_code::value(code),std::string(cursor_end+1,end));
+}
+
+inline size_t response::process_body(char const * buf, size_t len) {
+    // If no content length was set then we read forever and never set m_ready
+    if (m_read == 0) {
+        //m_body.append(buf,len);
+        //return len;
+        m_state = DONE;
+        return 0;
+    }
+
+    // Otherwise m_read is the number of bytes left.
+    size_t to_read;
+
+    if (len >= m_read) {
+        // if we have more bytes than we need read, read only the amount needed
+        // then set done state
+        to_read = m_read;
+        m_state = DONE;
+    } else {
+        // we need more bytes than are available, read them all
+        to_read = len;
+    }
+
+    m_body.append(buf,to_read);
+    m_read -= to_read;
+    return to_read;
+}
+
+} // namespace parser
+} // namespace http
+} // namespace websocketpp
+
+#endif // HTTP_PARSER_RESPONSE_IMPL_HPP
diff --git a/subprojects/websocketpp/websocketpp/http/parser.hpp b/subprojects/websocketpp/websocketpp/http/parser.hpp
new file mode 100644
index 000000000..9d309ec91
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/http/parser.hpp
@@ -0,0 +1,629 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef HTTP_PARSER_HPP
+#define HTTP_PARSER_HPP
+
+#include <algorithm>
+#include <map>
+#include <string>
+#include <utility>
+
+#include <websocketpp/utilities.hpp>
+#include <websocketpp/http/constants.hpp>
+
+namespace websocketpp {
+namespace http {
+namespace parser {
+
+namespace state {
+    enum value {
+        method,
+        resource,
+        version,
+        headers
+    };
+}
+
+namespace body_encoding {
+    enum value {
+        unknown,
+        plain,
+        chunked
+    };
+}
+
+typedef std::map<std::string, std::string, utility::ci_less > header_list;
+
+/// Read and return the next token in the stream
+/**
+ * Read until a non-token character is found and then return the token and
+ * iterator to the next character to read
+ *
+ * @param begin An iterator to the beginning of the sequence
+ * @param end An iterator to the end of the sequence
+ * @return A pair containing the token and an iterator to the next character in
+ * the stream
+ */
+template <typename InputIterator>
+std::pair<std::string,InputIterator> extract_token(InputIterator begin,
+    InputIterator end)
+{
+    InputIterator it = std::find_if(begin,end,&is_not_token_char);
+    return std::make_pair(std::string(begin,it),it);
+}
+
+/// Read and return the next quoted string in the stream
+/**
+ * Read a double quoted string starting at `begin`. The quotes themselves are
+ * stripped. The quoted value is returned along with an iterator to the next
+ * character to read
+ *
+ * @param begin An iterator to the beginning of the sequence
+ * @param end An iterator to the end of the sequence
+ * @return A pair containing the string read and an iterator to the next
+ * character in the stream
+ */
+template <typename InputIterator>
+std::pair<std::string,InputIterator> extract_quoted_string(InputIterator begin,
+    InputIterator end)
+{
+    std::string s;
+
+    if (end == begin) {
+        return std::make_pair(s,begin);
+    }
+
+    if (*begin != '"') {
+        return std::make_pair(s,begin);
+    }
+
+    InputIterator cursor = begin+1;
+    InputIterator marker = cursor;
+
+    cursor = std::find(cursor,end,'"');
+
+    while (cursor != end) {
+        // either this is the end or a quoted string
+        if (*(cursor-1) == '\\') {
+            s.append(marker,cursor-1);
+            s.append(1,'"');
+            ++cursor;
+            marker = cursor;
+        } else {
+            s.append(marker,cursor);
+            ++cursor;
+            return std::make_pair(s,cursor);
+        }
+
+        cursor = std::find(cursor,end,'"');
+    }
+
+    return std::make_pair("",begin);
+}
+
+/// Read and discard one unit of linear whitespace
+/**
+ * Read one unit of linear white space and return the iterator to the character
+ * afterwards. If `begin` is returned, no whitespace was extracted.
+ *
+ * @param begin An iterator to the beginning of the sequence
+ * @param end An iterator to the end of the sequence
+ * @return An iterator to the character after the linear whitespace read
+ */
+template <typename InputIterator>
+InputIterator extract_lws(InputIterator begin, InputIterator end) {
+    InputIterator it = begin;
+
+    // strip leading CRLF
+    if (end-begin > 2 && *begin == '\r' && *(begin+1) == '\n' &&
+        is_whitespace_char(static_cast<unsigned char>(*(begin+2))))
+    {
+        it+=3;
+    }
+
+    it = std::find_if(it,end,&is_not_whitespace_char);
+    return it;
+}
+
+/// Read and discard linear whitespace
+/**
+ * Read linear white space until a non-lws character is read and return an
+ * iterator to that character. If `begin` is returned, no whitespace was
+ * extracted.
+ *
+ * @param begin An iterator to the beginning of the sequence
+ * @param end An iterator to the end of the sequence
+ * @return An iterator to the character after the linear whitespace read
+ */
+template <typename InputIterator>
+InputIterator extract_all_lws(InputIterator begin, InputIterator end) {
+    InputIterator old_it;
+    InputIterator new_it = begin;
+
+    do {
+        // Pull value from previous iteration
+        old_it = new_it;
+
+        // look ahead another pass
+        new_it = extract_lws(old_it,end);
+    } while (new_it != end && old_it != new_it);
+
+    return new_it;
+}
+
+/// Extract HTTP attributes
+/**
+ * An http attributes list is a semicolon delimited list of key value pairs in
+ * the format: *( ";" attribute "=" value ) where attribute is a token and value
+ * is a token or quoted string.
+ *
+ * Attributes extracted are appended to the supplied attributes list
+ * `attributes`.
+ *
+ * @param [in] begin An iterator to the beginning of the sequence
+ * @param [in] end An iterator to the end of the sequence
+ * @param [out] attributes A reference to the attributes list to append
+ * attribute/value pairs extracted to
+ * @return An iterator to the character after the last atribute read
+ */
+template <typename InputIterator>
+InputIterator extract_attributes(InputIterator begin, InputIterator end,
+    attribute_list & attributes)
+{
+    InputIterator cursor;
+    bool first = true;
+
+    if (begin == end) {
+        return begin;
+    }
+
+    cursor = begin;
+    std::pair<std::string,InputIterator> ret;
+
+    while (cursor != end) {
+        std::string name;
+
+        cursor = http::parser::extract_all_lws(cursor,end);
+        if (cursor == end) {
+            break;
+        }
+
+        if (first) {
+            // ignore this check for the very first pass
+            first = false;
+        } else {
+            if (*cursor == ';') {
+                // advance past the ';'
+                ++cursor;
+            } else {
+                // non-semicolon in this position indicates end end of the
+                // attribute list, break and return.
+                break;
+            }
+        }
+
+        cursor = http::parser::extract_all_lws(cursor,end);
+        ret = http::parser::extract_token(cursor,end);
+
+        if (ret.first.empty()) {
+            // error: expected a token
+            return begin;
+        } else {
+            name = ret.first;
+            cursor = ret.second;
+        }
+
+        cursor = http::parser::extract_all_lws(cursor,end);
+        if (cursor == end || *cursor != '=') {
+            // if there is an equals sign, read the attribute value. Otherwise
+            // record a blank value and continue
+            attributes[name].clear();
+            continue;
+        }
+
+        // advance past the '='
+        ++cursor;
+
+        cursor = http::parser::extract_all_lws(cursor,end);
+        if (cursor == end) {
+            // error: expected a token or quoted string
+            return begin;
+        }
+
+        ret = http::parser::extract_quoted_string(cursor,end);
+        if (ret.second != cursor) {
+            attributes[name] = ret.first;
+            cursor = ret.second;
+            continue;
+        }
+
+        ret = http::parser::extract_token(cursor,end);
+        if (ret.first.empty()) {
+            // error : expected token or quoted string
+            return begin;
+        } else {
+            attributes[name] = ret.first;
+            cursor = ret.second;
+        }
+    }
+
+    return cursor;
+}
+
+/// Extract HTTP parameters
+/**
+ * An http parameters list is a comma delimited list of tokens followed by
+ * optional semicolon delimited attributes lists.
+ *
+ * Parameters extracted are appended to the supplied parameters list
+ * `parameters`.
+ *
+ * @param [in] begin An iterator to the beginning of the sequence
+ * @param [in] end An iterator to the end of the sequence
+ * @param [out] parameters A reference to the parameters list to append
+ * paramter values extracted to
+ * @return An iterator to the character after the last parameter read
+ */
+template <typename InputIterator>
+InputIterator extract_parameters(InputIterator begin, InputIterator end,
+    parameter_list &parameters)
+{
+    InputIterator cursor;
+
+    if (begin == end) {
+        // error: expected non-zero length range
+        return begin;
+    }
+
+    cursor = begin;
+    std::pair<std::string,InputIterator> ret;
+
+    /**
+     * LWS
+     * token
+     * LWS
+     * *(";" method-param)
+     * LWS
+     * ,=loop again
+     */
+    while (cursor != end) {
+        std::string parameter_name;
+        attribute_list attributes;
+
+        // extract any stray whitespace
+        cursor = http::parser::extract_all_lws(cursor,end);
+        if (cursor == end) {break;}
+
+        ret = http::parser::extract_token(cursor,end);
+
+        if (ret.first.empty()) {
+            // error: expected a token
+            return begin;
+        } else {
+            parameter_name = ret.first;
+            cursor = ret.second;
+        }
+
+        // Safe break point, insert parameter with blank attributes and exit
+        cursor = http::parser::extract_all_lws(cursor,end);
+        if (cursor == end) {
+            //parameters[parameter_name] = attributes;
+            parameters.push_back(std::make_pair(parameter_name,attributes));
+            break;
+        }
+
+        // If there is an attribute list, read it in
+        if (*cursor == ';') {
+            InputIterator acursor;
+
+            ++cursor;
+            acursor = http::parser::extract_attributes(cursor,end,attributes);
+
+            if (acursor == cursor) {
+                // attribute extraction ended in syntax error
+                return begin;
+            }
+
+            cursor = acursor;
+        }
+
+        // insert parameter into output list
+        //parameters[parameter_name] = attributes;
+        parameters.push_back(std::make_pair(parameter_name,attributes));
+
+        cursor = http::parser::extract_all_lws(cursor,end);
+        if (cursor == end) {break;}
+
+        // if next char is ',' then read another parameter, else stop
+        if (*cursor != ',') {
+            break;
+        }
+
+        // advance past comma
+        ++cursor;
+
+        if (cursor == end) {
+            // expected more bytes after a comma
+            return begin;
+        }
+    }
+
+    return cursor;
+}
+
+inline std::string strip_lws(std::string const & input) {
+    std::string::const_iterator begin = extract_all_lws(input.begin(),input.end());
+    if (begin == input.end()) {
+        return std::string();
+    }
+
+    std::string::const_reverse_iterator rbegin = extract_all_lws(input.rbegin(),input.rend());
+    if (rbegin == input.rend()) {
+        return std::string();
+    }
+
+    return std::string(begin,rbegin.base());
+}
+
+/// Base HTTP parser
+/**
+ * Includes methods and data elements common to all types of HTTP messages such
+ * as headers, versions, bodies, etc.
+ */
+class parser {
+public:
+    parser()
+      : m_header_bytes(0)
+      , m_body_bytes_needed(0)
+      , m_body_bytes_max(max_body_size)
+      , m_body_encoding(body_encoding::unknown) {}
+    
+    /// Get the HTTP version string
+    /**
+     * @return The version string for this parser
+     */
+    std::string const & get_version() const {
+        return m_version;
+    }
+
+    /// Set HTTP parser Version
+    /**
+     * Input should be in format: HTTP/x.y where x and y are positive integers.
+     * @todo Does this method need any validation?
+     *
+     * @param [in] version The value to set the HTTP version to.
+     */
+    void set_version(std::string const & version);
+
+    /// Get the value of an HTTP header
+    /**
+     * @todo Make this method case insensitive.
+     *
+     * @param [in] key The name/key of the header to get.
+     * @return The value associated with the given HTTP header key.
+     */
+    std::string const & get_header(std::string const & key) const;
+
+    /// Extract an HTTP parameter list from a parser header.
+    /**
+     * If the header requested doesn't exist or exists and is empty the
+     * parameter list is valid (but empty).
+     *
+     * @param [in] key The name/key of the HTTP header to use as input.
+     * @param [out] out The parameter list to store extracted parameters in.
+     * @return Whether or not the input was a valid parameter list.
+     */
+    bool get_header_as_plist(std::string const & key, parameter_list & out)
+        const;
+
+    /// Return a list of all HTTP headers
+    /**
+     * Return a list of all HTTP headers
+     *
+     * @since 0.8.0
+     *
+     * @return A list of all HTTP headers
+     */
+    header_list const & get_headers() const;
+
+    /// Append a value to an existing HTTP header
+    /**
+     * This method will set the value of the HTTP header `key` with the
+     * indicated value. If a header with the name `key` already exists, `val`
+     * will be appended to the existing value.
+     *
+     * @todo Make this method case insensitive.
+     * @todo Should there be any restrictions on which keys are allowed?
+     * @todo Exception free varient
+     *
+     * @see replace_header
+     *
+     * @param [in] key The name/key of the header to append to.
+     * @param [in] val The value to append.
+     */
+    void append_header(std::string const & key, std::string const & val);
+
+    /// Set a value for an HTTP header, replacing an existing value
+    /**
+     * This method will set the value of the HTTP header `key` with the
+     * indicated value. If a header with the name `key` already exists, `val`
+     * will replace the existing value.
+     *
+     * @todo Make this method case insensitive.
+     * @todo Should there be any restrictions on which keys are allowed?
+     * @todo Exception free varient
+     *
+     * @see append_header
+     *
+     * @param [in] key The name/key of the header to append to.
+     * @param [in] val The value to append.
+     */
+    void replace_header(std::string const & key, std::string const & val);
+
+    /// Remove a header from the parser
+    /**
+     * Removes the header entirely from the parser. This is different than
+     * setting the value of the header to blank.
+     *
+     * @todo Make this method case insensitive.
+     *
+     * @param [in] key The name/key of the header to remove.
+     */
+    void remove_header(std::string const & key);
+
+    /// Get HTTP body
+    /**
+     * Gets the body of the HTTP object
+     *
+     * @return The body of the HTTP message.
+     */
+    std::string const & get_body() const {
+        return m_body;
+    }
+
+    /// Set body content
+    /**
+     * Set the body content of the HTTP response to the parameter string. Note
+     * set_body will also set the Content-Length HTTP header to the appropriate
+     * value. If you want the Content-Length header to be something else, do so
+     * via replace_header("Content-Length") after calling set_body()
+     *
+     * @param value String data to include as the body content.
+     */
+    void set_body(std::string const & value);
+
+    /// Get body size limit
+    /**
+     * Retrieves the maximum number of bytes to parse & buffer before canceling
+     * a request.
+     *
+     * @since 0.5.0
+     *
+     * @return The maximum length of a message body.
+     */
+    size_t get_max_body_size() const {
+        return m_body_bytes_max;
+    }
+
+    /// Set body size limit
+    /**
+     * Set the maximum number of bytes to parse and buffer before canceling a
+     * request.
+     *
+     * @since 0.5.0
+     *
+     * @param value The size to set the max body length to.
+     */
+    void set_max_body_size(size_t value) {
+        m_body_bytes_max = value;
+    }
+
+    /// Extract an HTTP parameter list from a string.
+    /**
+     * @param [in] in The input string.
+     * @param [out] out The parameter list to store extracted parameters in.
+     * @return Whether or not the input was a valid parameter list.
+     */
+    bool parse_parameter_list(std::string const & in, parameter_list & out)
+        const;
+protected:
+    /// Process a header line
+    /**
+     * @todo Update this method to be exception free.
+     *
+     * @param [in] begin An iterator to the beginning of the sequence.
+     * @param [in] end An iterator to the end of the sequence.
+     */
+    void process_header(std::string::iterator begin, std::string::iterator end);
+
+    /// Prepare the parser to begin parsing body data
+    /**
+     * Inspects headers to determine if the message has a body that needs to be
+     * read. If so, sets up the necessary state, otherwise returns false. If
+     * this method returns true and loading the message body is desired call
+     * `process_body` until it returns zero bytes or an error.
+     *
+     * Must not be called until after all headers have been processed.
+     *
+     * @since 0.5.0
+     *
+     * @return True if more bytes are needed to load the body, false otherwise.
+     */
+    bool prepare_body();
+
+    /// Process body data
+    /**
+     * Parses body data.
+     *
+     * @since 0.5.0
+     *
+     * @param [in] begin An iterator to the beginning of the sequence.
+     * @param [in] end An iterator to the end of the sequence.
+     * @return The number of bytes processed
+     */
+    size_t process_body(char const * buf, size_t len);
+
+    /// Check if the parser is done parsing the body
+    /**
+     * Behavior before a call to `prepare_body` is undefined.
+     *
+     * @since 0.5.0
+     *
+     * @return True if the message body has been completed loaded.
+     */
+    bool body_ready() const {
+        return (m_body_bytes_needed == 0);
+    }
+
+    /// Generate and return the HTTP headers as a string
+    /**
+     * Each headers will be followed by the \r\n sequence including the last one.
+     * A second \r\n sequence (blank header) is not appended by this method
+     *
+     * @return The HTTP headers as a string.
+     */
+    std::string raw_headers() const;
+
+    std::string m_version;
+    header_list m_headers;
+    
+    size_t                  m_header_bytes;
+    
+    std::string             m_body;
+    size_t                  m_body_bytes_needed;
+    size_t                  m_body_bytes_max;
+    body_encoding::value    m_body_encoding;
+};
+
+} // namespace parser
+} // namespace http
+} // namespace websocketpp
+
+#include <websocketpp/http/impl/parser.hpp>
+
+#endif // HTTP_PARSER_HPP
diff --git a/subprojects/websocketpp/websocketpp/http/request.hpp b/subprojects/websocketpp/websocketpp/http/request.hpp
new file mode 100644
index 000000000..3355c99b8
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/http/request.hpp
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef HTTP_PARSER_REQUEST_HPP
+#define HTTP_PARSER_REQUEST_HPP
+
+#include <string>
+
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/http/parser.hpp>
+
+namespace websocketpp {
+namespace http {
+namespace parser {
+
+/// Stores, parses, and manipulates HTTP requests
+/**
+ * http::request provides the following functionality for working with HTTP
+ * requests.
+ *
+ * - Initialize request via manually setting each element
+ * - Initialize request via reading raw bytes and parsing
+ * - Once initialized, access individual parsed elements
+ * - Once initialized, read entire request as raw bytes
+ */
+class request : public parser {
+public:
+    typedef request type;
+    typedef lib::shared_ptr<type> ptr;
+
+    request()
+      : m_buf(lib::make_shared<std::string>())
+      , m_ready(false) {}
+
+    /// Process bytes in the input buffer
+    /**
+     * Process up to len bytes from input buffer buf. Returns the number of
+     * bytes processed. Bytes left unprocessed means bytes left over after the
+     * final header delimiters.
+     *
+     * Consume is a streaming processor. It may be called multiple times on one
+     * request and the full headers need not be available before processing can
+     * begin. If the end of the request was reached during this call to consume
+     * the ready flag will be set. Further calls to consume once ready will be
+     * ignored.
+     *
+     * Consume will throw an http::exception in the case of an error. Typical
+     * error reasons include malformed requests, incomplete requests, and max
+     * header size being reached.
+     *
+     * @param buf Pointer to byte buffer
+     * @param len Size of byte buffer
+     * @return Number of bytes processed.
+     */
+    size_t consume(char const * buf, size_t len);
+
+    /// Returns whether or not the request is ready for reading.
+    bool ready() const {
+        return m_ready;
+    }
+
+    /// Returns the full raw request (including the body)
+    std::string raw() const;
+    
+    /// Returns the raw request headers only (similar to an HTTP HEAD request)
+    std::string raw_head() const;
+
+    /// Set the HTTP method. Must be a valid HTTP token
+    void set_method(std::string const & method);
+
+    /// Return the request method
+    std::string const & get_method() const {
+        return m_method;
+    }
+
+    /// Set the HTTP uri. Must be a valid HTTP uri
+    void set_uri(std::string const & uri);
+
+    /// Return the requested URI
+    std::string const & get_uri() const {
+        return m_uri;
+    }
+
+private:
+    /// Helper function for message::consume. Process request line
+    void process(std::string::iterator begin, std::string::iterator end);
+
+    lib::shared_ptr<std::string>    m_buf;
+    std::string                     m_method;
+    std::string                     m_uri;
+    bool                            m_ready;
+};
+
+} // namespace parser
+} // namespace http
+} // namespace websocketpp
+
+#include <websocketpp/http/impl/request.hpp>
+
+#endif // HTTP_PARSER_REQUEST_HPP
diff --git a/subprojects/websocketpp/websocketpp/http/response.hpp b/subprojects/websocketpp/websocketpp/http/response.hpp
new file mode 100644
index 000000000..e724a3d3a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/http/response.hpp
@@ -0,0 +1,188 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef HTTP_PARSER_RESPONSE_HPP
+#define HTTP_PARSER_RESPONSE_HPP
+
+#include <iostream>
+#include <string>
+
+#include <websocketpp/http/parser.hpp>
+
+namespace websocketpp {
+namespace http {
+namespace parser {
+
+/// Stores, parses, and manipulates HTTP responses
+/**
+ * http::response provides the following functionality for working with HTTP
+ * responses.
+ *
+ * - Initialize response via manually setting each element
+ * - Initialize response via reading raw bytes and parsing
+ * - Once initialized, access individual parsed elements
+ * - Once initialized, read entire response as raw bytes
+ *
+ * http::response checks for header completeness separately from the full
+ * response. Once the header is complete, the Content-Length header is read to
+ * determine when to stop reading body bytes. If no Content-Length is present
+ * ready() will never return true. It is the responsibility of the caller to
+ * consume to determine when the response is complete (ie when the connection
+ * terminates, or some other metric).
+ */
+class response : public parser {
+public:
+    typedef response type;
+    typedef lib::shared_ptr<type> ptr;
+
+    response()
+      : m_read(0)
+      , m_buf(lib::make_shared<std::string>())
+      , m_status_code(status_code::uninitialized)
+      , m_state(RESPONSE_LINE) {}
+
+    /// Process bytes in the input buffer
+    /**
+     * Process up to len bytes from input buffer buf. Returns the number of
+     * bytes processed. Bytes left unprocessed means bytes left over after the
+     * final header delimiters.
+     *
+     * Consume is a streaming processor. It may be called multiple times on one
+     * response and the full headers need not be available before processing can
+     * begin. If the end of the response was reached during this call to consume
+     * the ready flag will be set. Further calls to consume once ready will be
+     * ignored.
+     *
+     * Consume will throw an http::exception in the case of an error. Typical
+     * error reasons include malformed responses, incomplete responses, and max
+     * header size being reached.
+     *
+     * @param buf Pointer to byte buffer
+     * @param len Size of byte buffer
+     * @return Number of bytes processed.
+     */
+    size_t consume(char const * buf, size_t len);
+
+    /// Process bytes in the input buffer (istream version)
+    /**
+     * Process bytes from istream s. Returns the number of bytes processed. 
+     * Bytes left unprocessed means bytes left over after the final header
+     * delimiters.
+     *
+     * Consume is a streaming processor. It may be called multiple times on one
+     * response and the full headers need not be available before processing can
+     * begin. If the end of the response was reached during this call to consume
+     * the ready flag will be set. Further calls to consume once ready will be
+     * ignored.
+     *
+     * Consume will throw an http::exception in the case of an error. Typical
+     * error reasons include malformed responses, incomplete responses, and max
+     * header size being reached.
+     *
+     * @param buf Pointer to byte buffer
+     * @param len Size of byte buffer
+     * @return Number of bytes processed.
+     */
+    size_t consume(std::istream & s);
+
+    /// Returns true if the response is ready.
+    /**
+     * @note will never return true if the content length header is not present
+     */
+    bool ready() const {
+        return m_state == DONE;
+    }
+
+    /// Returns true if the response headers are fully parsed.
+    bool headers_ready() const {
+        return (m_state == BODY || m_state == DONE);
+    }
+
+    /// Returns the full raw response
+    std::string raw() const;
+
+    /// Set response status code and message
+    /**
+     * Sets the response status code to `code` and looks up the corresponding
+     * message for standard codes. Non-standard codes will be entered as Unknown
+     * use set_status(status_code::value,std::string) overload to set both
+     * values explicitly.
+     *
+     * @param code Code to set
+     * @param msg Message to set
+     */
+    void set_status(status_code::value code);
+
+    /// Set response status code and message
+    /**
+     * Sets the response status code and message to independent custom values.
+     * use set_status(status_code::value) to set the code and have the standard
+     * message be automatically set.
+     *
+     * @param code Code to set
+     * @param msg Message to set
+     */
+    void set_status(status_code::value code, std::string const & msg);
+
+    /// Return the response status code
+    status_code::value get_status_code() const {
+        return m_status_code;
+    }
+
+    /// Return the response status message
+    const std::string& get_status_msg() const {
+        return m_status_msg;
+    }
+private:
+    /// Helper function for consume. Process response line
+    void process(std::string::iterator begin, std::string::iterator end);
+
+    /// Helper function for processing body bytes
+    size_t process_body(char const * buf, size_t len);
+
+    enum state {
+        RESPONSE_LINE = 0,
+        HEADERS = 1,
+        BODY = 2,
+        DONE = 3
+    };
+
+    std::string                     m_status_msg;
+    size_t                          m_read;
+    lib::shared_ptr<std::string>    m_buf;
+    status_code::value              m_status_code;
+    state                           m_state;
+
+};
+
+} // namespace parser
+} // namespace http
+} // namespace websocketpp
+
+#include <websocketpp/http/impl/response.hpp>
+
+#endif // HTTP_PARSER_RESPONSE_HPP
diff --git a/subprojects/websocketpp/websocketpp/impl/connection_impl.hpp b/subprojects/websocketpp/websocketpp/impl/connection_impl.hpp
new file mode 100644
index 000000000..bf88c9552
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/impl/connection_impl.hpp
@@ -0,0 +1,2375 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CONNECTION_IMPL_HPP
+#define WEBSOCKETPP_CONNECTION_IMPL_HPP
+
+#include <websocketpp/processors/hybi00.hpp>
+#include <websocketpp/processors/hybi07.hpp>
+#include <websocketpp/processors/hybi08.hpp>
+#include <websocketpp/processors/hybi13.hpp>
+
+#include <websocketpp/processors/processor.hpp>
+
+#include <websocketpp/common/platforms.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <algorithm>
+#include <exception>
+#include <sstream>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace websocketpp {
+
+namespace istate = session::internal_state;
+
+template <typename config>
+void connection<config>::set_termination_handler(
+    termination_handler new_handler)
+{
+    m_alog->write(log::alevel::devel,
+        "connection set_termination_handler");
+
+    //scoped_lock_type lock(m_connection_state_lock);
+
+    m_termination_handler = new_handler;
+}
+
+template <typename config>
+std::string const & connection<config>::get_origin() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_processor->get_origin(m_request);
+}
+
+template <typename config>
+size_t connection<config>::get_buffered_amount() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_send_buffer_size;
+}
+
+template <typename config>
+session::state::value connection<config>::get_state() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_state;
+}
+
+template <typename config>
+lib::error_code connection<config>::send(std::string const & payload,
+    frame::opcode::value op)
+{
+    message_ptr msg = m_msg_manager->get_message(op,payload.size());
+    msg->append_payload(payload);
+    msg->set_compressed(true);
+
+    return send(msg);
+}
+
+template <typename config>
+lib::error_code connection<config>::send(void const * payload, size_t len,
+    frame::opcode::value op)
+{
+    message_ptr msg = m_msg_manager->get_message(op,len);
+    msg->append_payload(payload,len);
+
+    return send(msg);
+}
+
+template <typename config>
+lib::error_code connection<config>::send(typename config::message_type::ptr msg)
+{
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"connection send");
+    }
+
+    {
+        scoped_lock_type lock(m_connection_state_lock);
+        if (m_state != session::state::open) {
+           return error::make_error_code(error::invalid_state);
+        }
+    }
+
+    message_ptr outgoing_msg;
+    bool needs_writing = false;
+
+    if (msg->get_prepared()) {
+        outgoing_msg = msg;
+
+        scoped_lock_type lock(m_write_lock);
+        write_push(outgoing_msg);
+        needs_writing = !m_write_flag && !m_send_queue.empty();
+    } else {
+        outgoing_msg = m_msg_manager->get_message();
+
+        if (!outgoing_msg) {
+            return error::make_error_code(error::no_outgoing_buffers);
+        }
+
+        scoped_lock_type lock(m_write_lock);
+        lib::error_code ec = m_processor->prepare_data_frame(msg,outgoing_msg);
+
+        if (ec) {
+            return ec;
+        }
+
+        write_push(outgoing_msg);
+        needs_writing = !m_write_flag && !m_send_queue.empty();
+    }
+
+    if (needs_writing) {
+        transport_con_type::dispatch(lib::bind(
+            &type::write_frame,
+            type::get_shared()
+        ));
+    }
+
+    return lib::error_code();
+}
+
+template <typename config>
+void connection<config>::ping(std::string const& payload, lib::error_code& ec) {
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"connection ping");
+    }
+
+    {
+        scoped_lock_type lock(m_connection_state_lock);
+        if (m_state != session::state::open) {
+            std::stringstream ss;
+            ss << "connection::ping called from invalid state " << m_state;
+            m_alog->write(log::alevel::devel,ss.str());
+            ec = error::make_error_code(error::invalid_state);
+            return;
+        }
+    }
+
+    message_ptr msg = m_msg_manager->get_message();
+    if (!msg) {
+        ec = error::make_error_code(error::no_outgoing_buffers);
+        return;
+    }
+
+    ec = m_processor->prepare_ping(payload,msg);
+    if (ec) {return;}
+
+    // set ping timer if we are listening for one
+    if (m_pong_timeout_handler) {
+        // Cancel any existing timers
+        if (m_ping_timer) {
+            m_ping_timer->cancel();
+        }
+
+        if (m_pong_timeout_dur > 0) {
+            m_ping_timer = transport_con_type::set_timer(
+                m_pong_timeout_dur,
+                lib::bind(
+                    &type::handle_pong_timeout,
+                    type::get_shared(),
+                    payload,
+                    lib::placeholders::_1
+                )
+            );
+        }
+
+        if (!m_ping_timer) {
+            // Our transport doesn't support timers
+            m_elog->write(log::elevel::warn,"Warning: a pong_timeout_handler is \
+                set but the transport in use does not support timeouts.");
+        }
+    }
+
+    bool needs_writing = false;
+    {
+        scoped_lock_type lock(m_write_lock);
+        write_push(msg);
+        needs_writing = !m_write_flag && !m_send_queue.empty();
+    }
+
+    if (needs_writing) {
+        transport_con_type::dispatch(lib::bind(
+            &type::write_frame,
+            type::get_shared()
+        ));
+    }
+
+    ec = lib::error_code();
+}
+
+template<typename config>
+void connection<config>::ping(std::string const & payload) {
+    lib::error_code ec;
+    ping(payload,ec);
+    if (ec) {
+        throw exception(ec);
+    }
+}
+
+template<typename config>
+void connection<config>::handle_pong_timeout(std::string payload,
+    lib::error_code const & ec)
+{
+    if (ec) {
+        if (ec == transport::error::operation_aborted) {
+            // ignore, this is expected
+            return;
+        }
+
+        m_elog->write(log::elevel::devel,"pong_timeout error: "+ec.message());
+        return;
+    }
+
+    if (m_pong_timeout_handler) {
+        m_pong_timeout_handler(m_connection_hdl,payload);
+    }
+}
+
+template <typename config>
+void connection<config>::pong(std::string const& payload, lib::error_code& ec) {
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"connection pong");
+    }
+
+    {
+        scoped_lock_type lock(m_connection_state_lock);
+        if (m_state != session::state::open) {
+            std::stringstream ss;
+            ss << "connection::pong called from invalid state " << m_state;
+            m_alog->write(log::alevel::devel,ss.str());
+            ec = error::make_error_code(error::invalid_state);
+            return;
+        }
+    }
+
+    message_ptr msg = m_msg_manager->get_message();
+    if (!msg) {
+        ec = error::make_error_code(error::no_outgoing_buffers);
+        return;
+    }
+
+    ec = m_processor->prepare_pong(payload,msg);
+    if (ec) {return;}
+
+    bool needs_writing = false;
+    {
+        scoped_lock_type lock(m_write_lock);
+        write_push(msg);
+        needs_writing = !m_write_flag && !m_send_queue.empty();
+    }
+
+    if (needs_writing) {
+        transport_con_type::dispatch(lib::bind(
+            &type::write_frame,
+            type::get_shared()
+        ));
+    }
+
+    ec = lib::error_code();
+}
+
+template<typename config>
+void connection<config>::pong(std::string const & payload) {
+    lib::error_code ec;
+    pong(payload,ec);
+    if (ec) {
+        throw exception(ec);
+    }
+}
+
+template <typename config>
+void connection<config>::close(close::status::value const code,
+    std::string const & reason, lib::error_code & ec)
+{
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"connection close");
+    }
+
+    // Truncate reason to maximum size allowable in a close frame.
+    std::string tr(reason,0,std::min<size_t>(reason.size(),
+        frame::limits::close_reason_size));
+
+    scoped_lock_type lock(m_connection_state_lock);
+
+    if (m_state != session::state::open) {
+       ec = error::make_error_code(error::invalid_state);
+       return;
+    }
+
+    ec = this->send_close_frame(code,tr,false,close::status::terminal(code));
+}
+
+template<typename config>
+void connection<config>::close(close::status::value const code,
+    std::string const & reason)
+{
+    lib::error_code ec;
+    close(code,reason,ec);
+    if (ec) {
+        throw exception(ec);
+    }
+}
+
+/// Trigger the on_interrupt handler
+/**
+ * This is thread safe if the transport is thread safe
+ */
+template <typename config>
+lib::error_code connection<config>::interrupt() {
+    m_alog->write(log::alevel::devel,"connection connection::interrupt");
+    return transport_con_type::interrupt(
+        lib::bind(
+            &type::handle_interrupt,
+            type::get_shared()
+        )
+    );
+}
+
+
+template <typename config>
+void connection<config>::handle_interrupt() {
+    if (m_interrupt_handler) {
+        m_interrupt_handler(m_connection_hdl);
+    }
+}
+
+template <typename config>
+lib::error_code connection<config>::pause_reading() {
+    m_alog->write(log::alevel::devel,"connection connection::pause_reading");
+    return transport_con_type::dispatch(
+        lib::bind(
+            &type::handle_pause_reading,
+            type::get_shared()
+        )
+    );
+}
+
+/// Pause reading handler. Not safe to call directly
+template <typename config>
+void connection<config>::handle_pause_reading() {
+    m_alog->write(log::alevel::devel,"connection connection::handle_pause_reading");
+    m_read_flag = false;
+}
+
+template <typename config>
+lib::error_code connection<config>::resume_reading() {
+    m_alog->write(log::alevel::devel,"connection connection::resume_reading");
+    return transport_con_type::dispatch(
+        lib::bind(
+            &type::handle_resume_reading,
+            type::get_shared()
+        )
+    );
+}
+
+/// Resume reading helper method. Not safe to call directly
+template <typename config>
+void connection<config>::handle_resume_reading() {
+   m_read_flag = true;
+   read_frame();
+}
+
+
+
+
+
+
+
+
+
+
+
+template <typename config>
+bool connection<config>::get_secure() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_uri->get_secure();
+}
+
+template <typename config>
+std::string const & connection<config>::get_host() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_uri->get_host();
+}
+
+template <typename config>
+std::string const & connection<config>::get_resource() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_uri->get_resource();
+}
+
+template <typename config>
+uint16_t connection<config>::get_port() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_uri->get_port();
+}
+
+template <typename config>
+uri_ptr connection<config>::get_uri() const {
+    //scoped_lock_type lock(m_connection_state_lock);
+    return m_uri;
+}
+
+template <typename config>
+void connection<config>::set_uri(uri_ptr uri) {
+    //scoped_lock_type lock(m_connection_state_lock);
+    m_uri = uri;
+}
+
+
+
+
+
+
+template <typename config>
+std::string const & connection<config>::get_subprotocol() const {
+    return m_subprotocol;
+}
+
+template <typename config>
+std::vector<std::string> const &
+connection<config>::get_requested_subprotocols() const {
+    return m_requested_subprotocols;
+}
+
+template <typename config>
+void connection<config>::add_subprotocol(std::string const & value,
+    lib::error_code & ec)
+{
+    if (m_is_server) {
+        ec = error::make_error_code(error::client_only);
+        return;
+    }
+
+    // If the value is empty or has a non-RFC2616 token character it is invalid.
+    if (value.empty() || std::find_if(value.begin(),value.end(),
+                                      http::is_not_token_char) != value.end())
+    {
+        ec = error::make_error_code(error::invalid_subprotocol);
+        return;
+    }
+
+    m_requested_subprotocols.push_back(value);
+}
+
+template <typename config>
+void connection<config>::add_subprotocol(std::string const & value) {
+    lib::error_code ec;
+    this->add_subprotocol(value,ec);
+    if (ec) {
+        throw exception(ec);
+    }
+}
+
+
+template <typename config>
+void connection<config>::select_subprotocol(std::string const & value,
+    lib::error_code & ec)
+{
+    if (!m_is_server) {
+        ec = error::make_error_code(error::server_only);
+        return;
+    }
+
+    if (value.empty()) {
+        ec = lib::error_code();
+        return;
+    }
+
+    std::vector<std::string>::iterator it;
+
+    it = std::find(m_requested_subprotocols.begin(),
+                   m_requested_subprotocols.end(),
+                   value);
+
+    if (it == m_requested_subprotocols.end()) {
+        ec = error::make_error_code(error::unrequested_subprotocol);
+        return;
+    }
+
+    m_subprotocol = value;
+}
+
+template <typename config>
+void connection<config>::select_subprotocol(std::string const & value) {
+    lib::error_code ec;
+    this->select_subprotocol(value,ec);
+    if (ec) {
+        throw exception(ec);
+    }
+}
+
+
+template <typename config>
+std::string const &
+connection<config>::get_request_header(std::string const & key) const {
+    return m_request.get_header(key);
+}
+
+template <typename config>
+std::string const &
+connection<config>::get_request_body() const {
+    return m_request.get_body();
+}
+
+template <typename config>
+std::string const &
+connection<config>::get_response_header(std::string const & key) const {
+    return m_response.get_header(key);
+}
+
+// TODO: EXCEPTION_FREE
+template <typename config>
+void connection<config>::set_status(http::status_code::value code)
+{
+    if (m_internal_state != istate::PROCESS_HTTP_REQUEST) {
+        throw exception("Call to set_status from invalid state",
+                      error::make_error_code(error::invalid_state));
+    }
+    m_response.set_status(code);
+}
+
+// TODO: EXCEPTION_FREE
+template <typename config>
+void connection<config>::set_status(http::status_code::value code,
+    std::string const & msg)
+{
+    if (m_internal_state != istate::PROCESS_HTTP_REQUEST) {
+        throw exception("Call to set_status from invalid state",
+                      error::make_error_code(error::invalid_state));
+    }
+
+    m_response.set_status(code,msg);
+}
+
+// TODO: EXCEPTION_FREE
+template <typename config>
+void connection<config>::set_body(std::string const & value) {
+    if (m_internal_state != istate::PROCESS_HTTP_REQUEST) {
+        throw exception("Call to set_status from invalid state",
+                      error::make_error_code(error::invalid_state));
+    }
+
+    m_response.set_body(value);
+}
+
+// TODO: EXCEPTION_FREE
+template <typename config>
+void connection<config>::append_header(std::string const & key,
+    std::string const & val)
+{
+    if (m_is_server) {
+        if (m_internal_state == istate::PROCESS_HTTP_REQUEST) {
+            // we are setting response headers for an incoming server connection
+            m_response.append_header(key,val);
+        } else {
+            throw exception("Call to append_header from invalid state",
+                      error::make_error_code(error::invalid_state));
+        }
+    } else {
+        if (m_internal_state == istate::USER_INIT) {
+            // we are setting initial headers for an outgoing client connection
+            m_request.append_header(key,val);
+        } else {
+            throw exception("Call to append_header from invalid state",
+                      error::make_error_code(error::invalid_state));
+        }
+    }
+}
+
+// TODO: EXCEPTION_FREE
+template <typename config>
+void connection<config>::replace_header(std::string const & key,
+    std::string const & val)
+{
+    if (m_is_server) {
+        if (m_internal_state == istate::PROCESS_HTTP_REQUEST) {
+            // we are setting response headers for an incoming server connection
+            m_response.replace_header(key,val);
+        } else {
+            throw exception("Call to replace_header from invalid state",
+                        error::make_error_code(error::invalid_state));
+        }
+    } else {
+        if (m_internal_state == istate::USER_INIT) {
+            // we are setting initial headers for an outgoing client connection
+            m_request.replace_header(key,val);
+        } else {
+            throw exception("Call to replace_header from invalid state",
+                        error::make_error_code(error::invalid_state));
+        }
+    }
+}
+
+// TODO: EXCEPTION_FREE
+template <typename config>
+void connection<config>::remove_header(std::string const & key)
+{
+    if (m_is_server) {
+        if (m_internal_state == istate::PROCESS_HTTP_REQUEST) {
+            // we are setting response headers for an incoming server connection
+            m_response.remove_header(key);
+        } else {
+            throw exception("Call to remove_header from invalid state",
+                        error::make_error_code(error::invalid_state));
+        }
+    } else {
+        if (m_internal_state == istate::USER_INIT) {
+            // we are setting initial headers for an outgoing client connection
+            m_request.remove_header(key);
+        } else {
+            throw exception("Call to remove_header from invalid state",
+                        error::make_error_code(error::invalid_state));
+        }
+    }
+}
+
+/// Defer HTTP Response until later
+/**
+ * Used in the http handler to defer the HTTP response for this connection
+ * until later. Handshake timers will be canceled and the connection will be
+ * left open until `send_http_response` or an equivalent is called.
+ *
+ * Warning: deferred connections won't time out and as a result can tie up
+ * resources.
+ *
+ * @return A status code, zero on success, non-zero otherwise
+ */
+template <typename config>
+lib::error_code connection<config>::defer_http_response() {
+    // Cancel handshake timer, otherwise the connection will time out and we'll
+    // close the connection before the app has a chance to send a response.
+    if (m_handshake_timer) {
+        m_handshake_timer->cancel();
+        m_handshake_timer.reset();
+    }
+    
+    // Do something to signal deferral
+    m_http_state = session::http_state::deferred;
+    
+    return lib::error_code();
+}
+
+/// Send deferred HTTP Response (exception free)
+/**
+ * Sends an http response to an HTTP connection that was deferred. This will
+ * send a complete response including all headers, status line, and body
+ * text. The connection will be closed afterwards.
+ *
+ * @since 0.6.0
+ *
+ * @param ec A status code, zero on success, non-zero otherwise
+ */
+template <typename config>
+void connection<config>::send_http_response(lib::error_code & ec) {
+    {
+        scoped_lock_type lock(m_connection_state_lock);
+        if (m_http_state != session::http_state::deferred) {
+            ec = error::make_error_code(error::invalid_state);
+            return;
+        }
+    
+        m_http_state = session::http_state::body_written;
+    }
+    
+    this->write_http_response(lib::error_code());
+    ec = lib::error_code();
+}
+
+template <typename config>
+void connection<config>::send_http_response() {
+    lib::error_code ec;
+    this->send_http_response(ec);
+    if (ec) {
+        throw exception(ec);
+    }
+}
+
+
+
+
+/******** logic thread ********/
+
+template <typename config>
+void connection<config>::start() {
+    m_alog->write(log::alevel::devel,"connection start");
+
+    if (m_internal_state != istate::USER_INIT) {
+        m_alog->write(log::alevel::devel,"Start called in invalid state");
+        this->terminate(error::make_error_code(error::invalid_state));
+        return;
+    }
+
+    m_internal_state = istate::TRANSPORT_INIT;
+
+    // Depending on how the transport implements init this function may return
+    // immediately and call handle_transport_init later or call
+    // handle_transport_init from this function.
+    transport_con_type::init(
+        lib::bind(
+            &type::handle_transport_init,
+            type::get_shared(),
+            lib::placeholders::_1
+        )
+    );
+}
+
+template <typename config>
+void connection<config>::handle_transport_init(lib::error_code const & ec) {
+    m_alog->write(log::alevel::devel,"connection handle_transport_init");
+
+    lib::error_code ecm = ec;
+
+    if (m_internal_state != istate::TRANSPORT_INIT) {
+        m_alog->write(log::alevel::devel,
+          "handle_transport_init must be called from transport init state");
+        ecm = error::make_error_code(error::invalid_state);
+    }
+
+    if (ecm) {
+        std::stringstream s;
+        s << "handle_transport_init received error: "<< ecm.message();
+        m_elog->write(log::elevel::rerror,s.str());
+
+        this->terminate(ecm);
+        return;
+    }
+
+    // At this point the transport is ready to read and write bytes.
+    if (m_is_server) {
+        m_internal_state = istate::READ_HTTP_REQUEST;
+        this->read_handshake(1);
+    } else {
+        // We are a client. Set the processor to the version specified in the
+        // config file and send a handshake request.
+        m_internal_state = istate::WRITE_HTTP_REQUEST;
+        m_processor = get_processor(config::client_version);
+        this->send_http_request();
+    }
+}
+
+template <typename config>
+void connection<config>::read_handshake(size_t num_bytes) {
+    m_alog->write(log::alevel::devel,"connection read_handshake");
+
+    if (m_open_handshake_timeout_dur > 0) {
+        m_handshake_timer = transport_con_type::set_timer(
+            m_open_handshake_timeout_dur,
+            lib::bind(
+                &type::handle_open_handshake_timeout,
+                type::get_shared(),
+                lib::placeholders::_1
+            )
+        );
+    }
+
+    transport_con_type::async_read_at_least(
+        num_bytes,
+        m_buf,
+        config::connection_read_buffer_size,
+        lib::bind(
+            &type::handle_read_handshake,
+            type::get_shared(),
+            lib::placeholders::_1,
+            lib::placeholders::_2
+        )
+    );
+}
+
+// All exit paths for this function need to call write_http_response() or submit
+// a new read request with this function as the handler.
+template <typename config>
+void connection<config>::handle_read_handshake(lib::error_code const & ec,
+    size_t bytes_transferred)
+{
+    m_alog->write(log::alevel::devel,"connection handle_read_handshake");
+
+    lib::error_code ecm = ec;
+
+    if (!ecm) {
+        scoped_lock_type lock(m_connection_state_lock);
+        
+        if (m_state == session::state::connecting) {
+             if (m_internal_state != istate::READ_HTTP_REQUEST) {
+                ecm = error::make_error_code(error::invalid_state);
+             }
+        } else if (m_state == session::state::closed) {
+            // The connection was canceled while the response was being sent,
+            // usually by the handshake timer. This is basically expected
+            // (though hopefully rare) and there is nothing we can do so ignore.
+            m_alog->write(log::alevel::devel,
+                "handle_read_handshake invoked after connection was closed");
+            return;
+        } else {
+            ecm = error::make_error_code(error::invalid_state);
+        }
+    }
+
+    if (ecm) {
+        if (ecm == transport::error::eof && m_state == session::state::closed) {
+            // we expect to get eof if the connection is closed already
+            m_alog->write(log::alevel::devel,
+                    "got (expected) eof/state error from closed con");
+            return;
+        }
+        
+        log_err(log::elevel::rerror,"handle_read_handshake",ecm);
+        this->terminate(ecm);
+        return;
+    }
+
+    // Boundaries checking. TODO: How much of this should be done?
+    if (bytes_transferred > config::connection_read_buffer_size) {
+        m_elog->write(log::elevel::fatal,"Fatal boundaries checking error.");
+        this->terminate(make_error_code(error::general));
+        return;
+    }
+
+    size_t bytes_processed = 0;
+    try {
+        bytes_processed = m_request.consume(m_buf,bytes_transferred);
+    } catch (http::exception &e) {
+        // All HTTP exceptions will result in this request failing and an error
+        // response being returned. No more bytes will be read in this con.
+        m_response.set_status(e.m_error_code,e.m_error_msg);
+        this->write_http_response_error(error::make_error_code(error::http_parse_error));
+        return;
+    }
+
+    // More paranoid boundaries checking.
+    // TODO: Is this overkill?
+    if (bytes_processed > bytes_transferred) {
+        m_elog->write(log::elevel::fatal,"Fatal boundaries checking error.");
+        this->terminate(make_error_code(error::general));
+        return;
+    }
+
+    if (m_alog->static_test(log::alevel::devel)) {
+        std::stringstream s;
+        s << "bytes_transferred: " << bytes_transferred
+          << " bytes, bytes processed: " << bytes_processed << " bytes";
+        m_alog->write(log::alevel::devel,s.str());
+    }
+
+    if (m_request.ready()) {
+        lib::error_code processor_ec = this->initialize_processor();
+        if (processor_ec) {
+            this->write_http_response_error(processor_ec);
+            return;
+        }
+
+        if (m_processor && m_processor->get_version() == 0) {
+            // Version 00 has an extra requirement to read some bytes after the
+            // handshake
+            if (bytes_transferred-bytes_processed >= 8) {
+                m_request.replace_header(
+                    "Sec-WebSocket-Key3",
+                    std::string(m_buf+bytes_processed,m_buf+bytes_processed+8)
+                );
+                bytes_processed += 8;
+            } else {
+                // TODO: need more bytes
+                m_alog->write(log::alevel::devel,"short key3 read");
+                m_response.set_status(http::status_code::internal_server_error);
+                this->write_http_response_error(processor::error::make_error_code(processor::error::short_key3));
+                return;
+            }
+        }
+
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,m_request.raw());
+            if (!m_request.get_header("Sec-WebSocket-Key3").empty()) {
+                m_alog->write(log::alevel::devel,
+                    utility::to_hex(m_request.get_header("Sec-WebSocket-Key3")));
+            }
+        }
+
+        // The remaining bytes in m_buf are frame data. Copy them to the
+        // beginning of the buffer and note the length. They will be read after
+        // the handshake completes and before more bytes are read.
+        std::copy(m_buf+bytes_processed,m_buf+bytes_transferred,m_buf);
+        m_buf_cursor = bytes_transferred-bytes_processed;
+
+
+        m_internal_state = istate::PROCESS_HTTP_REQUEST;
+        
+        // We have the complete request. Process it.
+        lib::error_code handshake_ec = this->process_handshake_request();
+        
+        // Write a response if this is a websocket connection or if it is an
+        // HTTP connection for which the response has not been deferred or
+        // started yet by a different system (i.e. still in init state).
+        if (!m_is_http || m_http_state == session::http_state::init) {
+            this->write_http_response(handshake_ec);
+        }
+    } else {
+        // read at least 1 more byte
+        transport_con_type::async_read_at_least(
+            1,
+            m_buf,
+            config::connection_read_buffer_size,
+            lib::bind(
+                &type::handle_read_handshake,
+                type::get_shared(),
+                lib::placeholders::_1,
+                lib::placeholders::_2
+            )
+        );
+    }
+}
+
+// write_http_response requires the request to be fully read and the connection
+// to be in the PROCESS_HTTP_REQUEST state. In some cases we can detect errors
+// before the request is fully read (specifically at a point where we aren't
+// sure if the hybi00 key3 bytes need to be read). This method sets the correct
+// state and calls write_http_response
+template <typename config>
+void connection<config>::write_http_response_error(lib::error_code const & ec) {
+    if (m_internal_state != istate::READ_HTTP_REQUEST) {
+        m_alog->write(log::alevel::devel,
+            "write_http_response_error called in invalid state");
+        this->terminate(error::make_error_code(error::invalid_state));
+        return;
+    }
+    
+    m_internal_state = istate::PROCESS_HTTP_REQUEST;
+    
+    this->write_http_response(ec);
+}
+
+// All exit paths for this function need to call write_http_response() or submit
+// a new read request with this function as the handler.
+template <typename config>
+void connection<config>::handle_read_frame(lib::error_code const & ec,
+    size_t bytes_transferred)
+{
+    //m_alog->write(log::alevel::devel,"connection handle_read_frame");
+
+    lib::error_code ecm = ec;
+
+    if (!ecm && m_internal_state != istate::PROCESS_CONNECTION) {
+        ecm = error::make_error_code(error::invalid_state);
+    }
+
+    if (ecm) {
+        log::level echannel = log::elevel::rerror;
+        
+        if (ecm == transport::error::eof) {
+            if (m_state == session::state::closed) {
+                // we expect to get eof if the connection is closed already
+                // just ignore it
+                m_alog->write(log::alevel::devel,"got eof from closed con");
+                return;
+            } else if (m_state == session::state::closing && !m_is_server) {
+                // If we are a client we expect to get eof in the closing state,
+                // this is a signal to terminate our end of the connection after
+                // the closing handshake
+                terminate(lib::error_code());
+                return;
+            }
+        } else if (ecm == error::invalid_state) {
+            // In general, invalid state errors in the closed state are the
+            // result of handlers that were in the system already when the state
+            // changed and should be ignored as they pose no problems and there
+            // is nothing useful that we can do about them.
+            if (m_state == session::state::closed) {
+                m_alog->write(log::alevel::devel,
+                    "handle_read_frame: got invalid istate in closed state");
+                return;
+            }
+        } else if (ecm == transport::error::action_after_shutdown) {
+            echannel = log::elevel::info;
+        } else {
+            // TODO: more generally should we do something different here in the
+            // case that m_state is cosed? Are errors after the connection is
+            // already closed really an rerror?
+        }
+        
+        
+        
+        log_err(echannel, "handle_read_frame", ecm);
+        this->terminate(ecm);
+        return;
+    }
+
+    // Boundaries checking. TODO: How much of this should be done?
+    /*if (bytes_transferred > config::connection_read_buffer_size) {
+        m_elog->write(log::elevel::fatal,"Fatal boundaries checking error");
+        this->terminate(make_error_code(error::general));
+        return;
+    }*/
+
+    size_t p = 0;
+
+    if (m_alog->static_test(log::alevel::devel)) {
+        std::stringstream s;
+        s << "p = " << p << " bytes transferred = " << bytes_transferred;
+        m_alog->write(log::alevel::devel,s.str());
+    }
+
+    while (p < bytes_transferred) {
+        if (m_alog->static_test(log::alevel::devel)) {
+            std::stringstream s;
+            s << "calling consume with " << bytes_transferred-p << " bytes";
+            m_alog->write(log::alevel::devel,s.str());
+        }
+
+        lib::error_code consume_ec;
+
+        if (m_alog->static_test(log::alevel::devel)) {
+            std::stringstream s;
+            s << "Processing Bytes: " << utility::to_hex(reinterpret_cast<uint8_t*>(m_buf)+p,bytes_transferred-p);
+            m_alog->write(log::alevel::devel,s.str());
+        }
+
+        p += m_processor->consume(
+            reinterpret_cast<uint8_t*>(m_buf)+p,
+            bytes_transferred-p,
+            consume_ec
+        );
+
+        if (m_alog->static_test(log::alevel::devel)) {
+            std::stringstream s;
+            s << "bytes left after consume: " << bytes_transferred-p;
+            m_alog->write(log::alevel::devel,s.str());
+        }
+        if (consume_ec) {
+            log_err(log::elevel::rerror, "consume", consume_ec);
+
+            if (config::drop_on_protocol_error) {
+                this->terminate(consume_ec);
+                return;
+            } else {
+                lib::error_code close_ec;
+                this->close(
+                    processor::error::to_ws(consume_ec),
+                    consume_ec.message(),
+                    close_ec
+                );
+
+                if (close_ec) {
+                    log_err(log::elevel::fatal, "Protocol error close frame ", close_ec);
+                    this->terminate(close_ec);
+                    return;
+                }
+            }
+            return;
+        }
+
+        if (m_processor->ready()) {
+            if (m_alog->static_test(log::alevel::devel)) {
+                std::stringstream s;
+                s << "Complete message received. Dispatching";
+                m_alog->write(log::alevel::devel,s.str());
+            }
+
+            message_ptr msg = m_processor->get_message();
+
+            if (!msg) {
+                m_alog->write(log::alevel::devel, "null message from m_processor");
+            } else if (!is_control(msg->get_opcode())) {
+                // data message, dispatch to user
+                if (m_state != session::state::open) {
+                    m_elog->write(log::elevel::warn, "got non-close frame while closing");
+                } else if (m_message_handler) {
+                    m_message_handler(m_connection_hdl, msg);
+                }
+            } else {
+                process_control_frame(msg);
+            }
+        }
+    }
+
+    read_frame();
+}
+
+/// Issue a new transport read unless reading is paused.
+template <typename config>
+void connection<config>::read_frame() {
+    if (!m_read_flag) {
+        return;
+    }
+    
+    transport_con_type::async_read_at_least(
+        // std::min wont work with undefined static const values.
+        // TODO: is there a more elegant way to do this?
+        // Need to determine if requesting 1 byte or the exact number of bytes
+        // is better here. 1 byte lets us be a bit more responsive at a
+        // potential expense of additional runs through handle_read_frame
+        /*(m_processor->get_bytes_needed() > config::connection_read_buffer_size ?
+         config::connection_read_buffer_size : m_processor->get_bytes_needed())*/
+        1,
+        m_buf,
+        config::connection_read_buffer_size,
+        m_handle_read_frame
+    );
+}
+
+template <typename config>
+lib::error_code connection<config>::initialize_processor() {
+    m_alog->write(log::alevel::devel,"initialize_processor");
+
+    // if it isn't a websocket handshake nothing to do.
+    if (!processor::is_websocket_handshake(m_request)) {
+        return lib::error_code();
+    }
+
+    int version = processor::get_websocket_version(m_request);
+
+    if (version < 0) {
+        m_alog->write(log::alevel::devel, "BAD REQUEST: can't determine version");
+        m_response.set_status(http::status_code::bad_request);
+        return error::make_error_code(error::invalid_version);
+    }
+
+    m_processor = get_processor(version);
+
+    // if the processor is not null we are done
+    if (m_processor) {
+        return lib::error_code();
+    }
+
+    // We don't have a processor for this version. Return bad request
+    // with Sec-WebSocket-Version header filled with values we do accept
+    m_alog->write(log::alevel::devel, "BAD REQUEST: no processor for version");
+    m_response.set_status(http::status_code::bad_request);
+
+    std::stringstream ss;
+    std::string sep;
+    std::vector<int>::const_iterator it;
+    for (it = versions_supported.begin(); it != versions_supported.end(); it++)
+    {
+        ss << sep << *it;
+        sep = ",";
+    }
+
+    m_response.replace_header("Sec-WebSocket-Version",ss.str());
+    return error::make_error_code(error::unsupported_version);
+}
+
+template <typename config>
+lib::error_code connection<config>::process_handshake_request() {
+    m_alog->write(log::alevel::devel,"process handshake request");
+
+    if (!processor::is_websocket_handshake(m_request)) {
+        // this is not a websocket handshake. Process as plain HTTP
+        m_alog->write(log::alevel::devel,"HTTP REQUEST");
+
+        // extract URI from request
+        m_uri = processor::get_uri_from_host(
+            m_request,
+            (transport_con_type::is_secure() ? "https" : "http")
+        );
+
+        if (!m_uri->get_valid()) {
+            m_alog->write(log::alevel::devel, "Bad request: failed to parse uri");
+            m_response.set_status(http::status_code::bad_request);
+            return error::make_error_code(error::invalid_uri);
+        }
+
+        if (m_http_handler) {
+            m_is_http = true;
+            m_http_handler(m_connection_hdl);
+            
+            if (m_state == session::state::closed) {
+                return error::make_error_code(error::http_connection_ended);
+            }
+        } else {
+            set_status(http::status_code::upgrade_required);
+            return error::make_error_code(error::upgrade_required);
+        }
+
+        return lib::error_code();
+    }
+
+    lib::error_code ec = m_processor->validate_handshake(m_request);
+
+    // Validate: make sure all required elements are present.
+    if (ec){
+        // Not a valid handshake request
+        m_alog->write(log::alevel::devel, "Bad request " + ec.message());
+        m_response.set_status(http::status_code::bad_request);
+        return ec;
+    }
+
+    // Read extension parameters and set up values necessary for the end user
+    // to complete extension negotiation.
+    std::pair<lib::error_code,std::string> neg_results;
+    neg_results = m_processor->negotiate_extensions(m_request);
+
+    if (neg_results.first == processor::error::make_error_code(processor::error::extension_parse_error)) {
+        // There was a fatal error in extension parsing that should result in
+        // a failed connection attempt.
+        m_elog->write(log::elevel::info, "Bad request: " + neg_results.first.message());
+        m_response.set_status(http::status_code::bad_request);
+        return neg_results.first;
+    } else if (neg_results.first) {
+        // There was a fatal error in extension processing that is probably our
+        // fault. Consider extension negotiation to have failed and continue as
+        // if extensions were not supported
+        m_elog->write(log::elevel::info, 
+            "Extension negotiation failed: " + neg_results.first.message());
+    } else {
+        // extension negotiation succeeded, set response header accordingly
+        // we don't send an empty extensions header because it breaks many
+        // clients.
+        if (neg_results.second.size() > 0) {
+            m_response.replace_header("Sec-WebSocket-Extensions",
+                neg_results.second);
+        }
+    }
+
+    // extract URI from request
+    m_uri = m_processor->get_uri(m_request);
+
+
+    if (!m_uri->get_valid()) {
+        m_alog->write(log::alevel::devel, "Bad request: failed to parse uri");
+        m_response.set_status(http::status_code::bad_request);
+        return error::make_error_code(error::invalid_uri);
+    }
+
+    // extract subprotocols
+    lib::error_code subp_ec = m_processor->extract_subprotocols(m_request,
+        m_requested_subprotocols);
+
+    if (subp_ec) {
+        // should we do anything?
+    }
+
+    // Ask application to validate the connection
+    if (!m_validate_handler || m_validate_handler(m_connection_hdl)) {
+        m_response.set_status(http::status_code::switching_protocols);
+
+        // Write the appropriate response headers based on request and
+        // processor version
+        ec = m_processor->process_handshake(m_request,m_subprotocol,m_response);
+
+        if (ec) {
+            std::stringstream s;
+            s << "Processing error: " << ec << "(" << ec.message() << ")";
+            m_alog->write(log::alevel::devel, s.str());
+
+            m_response.set_status(http::status_code::internal_server_error);
+            return ec;
+        }
+    } else {
+        // User application has rejected the handshake
+        m_alog->write(log::alevel::devel, "USER REJECT");
+
+        // Use Bad Request if the user handler did not provide a more
+        // specific http response error code.
+        // TODO: is there a better default?
+        if (m_response.get_status_code() == http::status_code::uninitialized) {
+            m_response.set_status(http::status_code::bad_request);
+        }
+        
+        return error::make_error_code(error::rejected);
+    }
+
+    return lib::error_code();
+}
+
+template <typename config>
+void connection<config>::write_http_response(lib::error_code const & ec) {
+    m_alog->write(log::alevel::devel,"connection write_http_response");
+
+    if (ec == error::make_error_code(error::http_connection_ended)) {
+        m_alog->write(log::alevel::http,"An HTTP handler took over the connection.");
+        return;
+    }
+
+    if (m_response.get_status_code() == http::status_code::uninitialized) {
+        m_response.set_status(http::status_code::internal_server_error);
+        m_ec = error::make_error_code(error::general);
+    } else {
+        m_ec = ec;
+    }
+
+    m_response.set_version("HTTP/1.1");
+
+    // Set server header based on the user agent settings
+    if (m_response.get_header("Server").empty()) {
+        if (!m_user_agent.empty()) {
+            m_response.replace_header("Server",m_user_agent);
+        } else {
+            m_response.remove_header("Server");
+        }
+    }
+
+    // have the processor generate the raw bytes for the wire (if it exists)
+    if (m_processor) {
+        m_handshake_buffer = m_processor->get_raw(m_response);
+    } else {
+        // a processor wont exist for raw HTTP responses.
+        m_handshake_buffer = m_response.raw();
+    }
+
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"Raw Handshake response:\n"+m_handshake_buffer);
+        if (!m_response.get_header("Sec-WebSocket-Key3").empty()) {
+            m_alog->write(log::alevel::devel,
+                utility::to_hex(m_response.get_header("Sec-WebSocket-Key3")));
+        }
+    }
+
+    // write raw bytes
+    transport_con_type::async_write(
+        m_handshake_buffer.data(),
+        m_handshake_buffer.size(),
+        lib::bind(
+            &type::handle_write_http_response,
+            type::get_shared(),
+            lib::placeholders::_1
+        )
+    );
+}
+
+template <typename config>
+void connection<config>::handle_write_http_response(lib::error_code const & ec) {
+    m_alog->write(log::alevel::devel,"handle_write_http_response");
+
+    lib::error_code ecm = ec;
+
+    if (!ecm) {
+        scoped_lock_type lock(m_connection_state_lock);
+        
+        if (m_state == session::state::connecting) {
+             if (m_internal_state != istate::PROCESS_HTTP_REQUEST) {
+                ecm = error::make_error_code(error::invalid_state);
+             }
+        } else if (m_state == session::state::closed) {
+            // The connection was canceled while the response was being sent,
+            // usually by the handshake timer. This is basically expected
+            // (though hopefully rare) and there is nothing we can do so ignore.
+            m_alog->write(log::alevel::devel,
+                "handle_write_http_response invoked after connection was closed");
+            return;
+        } else {
+            ecm = error::make_error_code(error::invalid_state);
+        }
+    }
+
+    if (ecm) {
+        if (ecm == transport::error::eof && m_state == session::state::closed) {
+            // we expect to get eof if the connection is closed already
+            m_alog->write(log::alevel::devel,
+                    "got (expected) eof/state error from closed con");
+            return;
+        }
+        
+        log_err(log::elevel::rerror,"handle_write_http_response",ecm);
+        this->terminate(ecm);
+        return;
+    }
+
+    if (m_handshake_timer) {
+        m_handshake_timer->cancel();
+        m_handshake_timer.reset();
+    }
+
+    if (m_response.get_status_code() != http::status_code::switching_protocols)
+    {
+        /*if (m_processor || m_ec == error::http_parse_error || 
+            m_ec == error::invalid_version || m_ec == error::unsupported_version
+            || m_ec == error::upgrade_required)
+        {*/
+        if (!m_is_http) {
+            std::stringstream s;
+            s << "Handshake ended with HTTP error: "
+              << m_response.get_status_code();
+            m_elog->write(log::elevel::rerror,s.str());
+        } else {
+            // if this was not a websocket connection, we have written
+            // the expected response and the connection can be closed.
+            
+            this->log_http_result();
+            
+            if (m_ec) {
+                m_alog->write(log::alevel::devel,
+                    "got to writing HTTP results with m_ec set: "+m_ec.message());
+            }
+            m_ec = make_error_code(error::http_connection_ended);
+        }        
+        
+        this->terminate(m_ec);
+        return;
+    }
+
+    this->log_open_result();
+
+    m_internal_state = istate::PROCESS_CONNECTION;
+    m_state = session::state::open;
+
+    if (m_open_handler) {
+        m_open_handler(m_connection_hdl);
+    }
+
+    this->handle_read_frame(lib::error_code(), m_buf_cursor);
+}
+
+template <typename config>
+void connection<config>::send_http_request() {
+    m_alog->write(log::alevel::devel,"connection send_http_request");
+
+    // TODO: origin header?
+
+    // Have the protocol processor fill in the appropriate fields based on the
+    // selected client version
+    if (m_processor) {
+        lib::error_code ec;
+        ec = m_processor->client_handshake_request(m_request,m_uri,
+            m_requested_subprotocols);
+
+        if (ec) {
+            log_err(log::elevel::fatal,"Internal library error: Processor",ec);
+            return;
+        }
+    } else {
+        m_elog->write(log::elevel::fatal,"Internal library error: missing processor");
+        return;
+    }
+
+    // Unless the user has overridden the user agent, send generic WS++ UA.
+    if (m_request.get_header("User-Agent").empty()) {
+        if (!m_user_agent.empty()) {
+            m_request.replace_header("User-Agent",m_user_agent);
+        } else {
+            m_request.remove_header("User-Agent");
+        }
+    }
+
+    m_handshake_buffer = m_request.raw();
+
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"Raw Handshake request:\n"+m_handshake_buffer);
+    }
+
+    if (m_open_handshake_timeout_dur > 0) {
+        m_handshake_timer = transport_con_type::set_timer(
+            m_open_handshake_timeout_dur,
+            lib::bind(
+                &type::handle_open_handshake_timeout,
+                type::get_shared(),
+                lib::placeholders::_1
+            )
+        );
+    }
+
+    transport_con_type::async_write(
+        m_handshake_buffer.data(),
+        m_handshake_buffer.size(),
+        lib::bind(
+            &type::handle_send_http_request,
+            type::get_shared(),
+            lib::placeholders::_1
+        )
+    );
+}
+
+template <typename config>
+void connection<config>::handle_send_http_request(lib::error_code const & ec) {
+    m_alog->write(log::alevel::devel,"handle_send_http_request");
+
+    lib::error_code ecm = ec;
+
+    if (!ecm) {
+        scoped_lock_type lock(m_connection_state_lock);
+        
+        if (m_state == session::state::connecting) {
+             if (m_internal_state != istate::WRITE_HTTP_REQUEST) {
+                ecm = error::make_error_code(error::invalid_state);
+             } else {
+                m_internal_state = istate::READ_HTTP_RESPONSE;
+             }
+        } else if (m_state == session::state::closed) {
+            // The connection was canceled while the response was being sent,
+            // usually by the handshake timer. This is basically expected
+            // (though hopefully rare) and there is nothing we can do so ignore.
+            m_alog->write(log::alevel::devel,
+                "handle_send_http_request invoked after connection was closed");
+            return;
+        } else {
+            ecm = error::make_error_code(error::invalid_state);
+        }
+    }
+
+    if (ecm) {
+        if (ecm == transport::error::eof && m_state == session::state::closed) {
+            // we expect to get eof if the connection is closed already
+            m_alog->write(log::alevel::devel,
+                    "got (expected) eof/state error from closed con");
+            return;
+        }
+        
+        log_err(log::elevel::rerror,"handle_send_http_request",ecm);
+        this->terminate(ecm);
+        return;
+    }
+
+    transport_con_type::async_read_at_least(
+        1,
+        m_buf,
+        config::connection_read_buffer_size,
+        lib::bind(
+            &type::handle_read_http_response,
+            type::get_shared(),
+            lib::placeholders::_1,
+            lib::placeholders::_2
+        )
+    );
+}
+
+template <typename config>
+void connection<config>::handle_read_http_response(lib::error_code const & ec,
+    size_t bytes_transferred)
+{
+    m_alog->write(log::alevel::devel,"handle_read_http_response");
+
+    lib::error_code ecm = ec;
+
+    if (!ecm) {
+        scoped_lock_type lock(m_connection_state_lock);
+        
+        if (m_state == session::state::connecting) {
+            if (m_internal_state != istate::READ_HTTP_RESPONSE) {
+                ecm = error::make_error_code(error::invalid_state);
+            }
+        } else if (m_state == session::state::closed) {
+            // The connection was canceled while the response was being sent,
+            // usually by the handshake timer. This is basically expected
+            // (though hopefully rare) and there is nothing we can do so ignore.
+            m_alog->write(log::alevel::devel,
+                "handle_read_http_response invoked after connection was closed");
+            return;
+        } else {
+            ecm = error::make_error_code(error::invalid_state);
+        }
+    }
+
+    if (ecm) {
+        if (ecm == transport::error::eof && m_state == session::state::closed) {
+            // we expect to get eof if the connection is closed already
+            m_alog->write(log::alevel::devel,
+                    "got (expected) eof/state error from closed con");
+            return;
+        }
+        
+        log_err(log::elevel::rerror,"handle_read_http_response",ecm);
+        this->terminate(ecm);
+        return;
+    }
+    
+    size_t bytes_processed = 0;
+    // TODO: refactor this to use error codes rather than exceptions
+    try {
+        bytes_processed = m_response.consume(m_buf,bytes_transferred);
+    } catch (http::exception & e) {
+        m_elog->write(log::elevel::rerror,
+            std::string("error in handle_read_http_response: ")+e.what());
+        this->terminate(make_error_code(error::general));
+        return;
+    }
+
+    m_alog->write(log::alevel::devel,std::string("Raw response: ")+m_response.raw());
+
+    if (m_response.headers_ready()) {
+        if (m_handshake_timer) {
+            m_handshake_timer->cancel();
+            m_handshake_timer.reset();
+        }
+
+        lib::error_code validate_ec = m_processor->validate_server_handshake_response(
+            m_request,
+            m_response
+        );
+        if (validate_ec) {
+            log_err(log::elevel::rerror,"Server handshake response",validate_ec);
+            this->terminate(validate_ec);
+            return;
+        }
+
+        // Read extension parameters and set up values necessary for the end
+        // user to complete extension negotiation.
+        std::pair<lib::error_code,std::string> neg_results;
+        neg_results = m_processor->negotiate_extensions(m_response);
+
+        if (neg_results.first) {
+            // There was a fatal error in extension negotiation. For the moment
+            // kill all connections that fail extension negotiation.
+            
+            // TODO: deal with cases where the response is well formed but 
+            // doesn't match the options requested by the client. Its possible
+            // that the best behavior in this cases is to log and continue with
+            // an unextended connection.
+            m_alog->write(log::alevel::devel, "Extension negotiation failed: "
+                + neg_results.first.message());
+            this->terminate(make_error_code(error::extension_neg_failed));
+            // TODO: close connection with reason 1010 (and list extensions)
+        }
+
+        // response is valid, connection can now be assumed to be open      
+        m_internal_state = istate::PROCESS_CONNECTION;
+        m_state = session::state::open;
+
+        this->log_open_result();
+
+        if (m_open_handler) {
+            m_open_handler(m_connection_hdl);
+        }
+
+        // The remaining bytes in m_buf are frame data. Copy them to the
+        // beginning of the buffer and note the length. They will be read after
+        // the handshake completes and before more bytes are read.
+        std::copy(m_buf+bytes_processed,m_buf+bytes_transferred,m_buf);
+        m_buf_cursor = bytes_transferred-bytes_processed;
+
+        this->handle_read_frame(lib::error_code(), m_buf_cursor);
+    } else {
+        transport_con_type::async_read_at_least(
+            1,
+            m_buf,
+            config::connection_read_buffer_size,
+            lib::bind(
+                &type::handle_read_http_response,
+                type::get_shared(),
+                lib::placeholders::_1,
+                lib::placeholders::_2
+            )
+        );
+    }
+}
+
+template <typename config>
+void connection<config>::handle_open_handshake_timeout(
+    lib::error_code const & ec)
+{
+    if (ec == transport::error::operation_aborted) {
+        m_alog->write(log::alevel::devel,"open handshake timer cancelled");
+    } else if (ec) {
+        m_alog->write(log::alevel::devel,
+            "open handle_open_handshake_timeout error: "+ec.message());
+        // TODO: ignore or fail here?
+    } else {
+        m_alog->write(log::alevel::devel,"open handshake timer expired");
+        terminate(make_error_code(error::open_handshake_timeout));
+    }
+}
+
+template <typename config>
+void connection<config>::handle_close_handshake_timeout(
+    lib::error_code const & ec)
+{
+    if (ec == transport::error::operation_aborted) {
+        m_alog->write(log::alevel::devel,"asio close handshake timer cancelled");
+    } else if (ec) {
+        m_alog->write(log::alevel::devel,
+            "asio open handle_close_handshake_timeout error: "+ec.message());
+        // TODO: ignore or fail here?
+    } else {
+        m_alog->write(log::alevel::devel, "asio close handshake timer expired");
+        terminate(make_error_code(error::close_handshake_timeout));
+    }
+}
+
+template <typename config>
+void connection<config>::terminate(lib::error_code const & ec) {
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"connection terminate");
+    }
+
+    // Cancel close handshake timer
+    if (m_handshake_timer) {
+        m_handshake_timer->cancel();
+        m_handshake_timer.reset();
+    }
+
+    terminate_status tstat = unknown;
+    if (ec) {
+        m_ec = ec;
+        m_local_close_code = close::status::abnormal_close;
+        m_local_close_reason = ec.message();
+    }
+
+    // TODO: does any of this need a mutex?
+    if (m_is_http) {
+        m_http_state = session::http_state::closed;
+    }
+    if (m_state == session::state::connecting) {
+        m_state = session::state::closed;
+        tstat = failed;
+        
+        // Log fail result here before socket is shut down and we can't get
+        // the remote address, etc anymore
+        if (m_ec != error::http_connection_ended) {
+            log_fail_result();
+        }
+    } else if (m_state != session::state::closed) {
+        m_state = session::state::closed;
+        tstat = closed;
+    } else {
+        m_alog->write(log::alevel::devel,
+            "terminate called on connection that was already terminated");
+        return;
+    }
+
+    // TODO: choose between shutdown and close based on error code sent
+
+    transport_con_type::async_shutdown(
+        lib::bind(
+            &type::handle_terminate,
+            type::get_shared(),
+            tstat,
+            lib::placeholders::_1
+        )
+    );
+}
+
+template <typename config>
+void connection<config>::handle_terminate(terminate_status tstat,
+    lib::error_code const & ec)
+{
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"connection handle_terminate");
+    }
+
+    if (ec) {
+        // there was an error actually shutting down the connection
+        log_err(log::elevel::devel,"handle_terminate",ec);
+    }
+
+    // clean shutdown
+    if (tstat == failed) {
+        if (m_ec != error::http_connection_ended) {
+            if (m_fail_handler) {
+                m_fail_handler(m_connection_hdl);
+            }
+        }
+    } else if (tstat == closed) {
+        if (m_close_handler) {
+            m_close_handler(m_connection_hdl);
+        }
+        log_close_result();
+    } else {
+        m_elog->write(log::elevel::rerror,"Unknown terminate_status");
+    }
+
+    // call the termination handler if it exists
+    // if it exists it might (but shouldn't) refer to a bad memory location.
+    // If it does, we don't care and should catch and ignore it.
+    if (m_termination_handler) {
+        try {
+            m_termination_handler(type::get_shared());
+        } catch (std::exception const & e) {
+            m_elog->write(log::elevel::warn,
+                std::string("termination_handler call failed. Reason was: ")+e.what());
+        }
+    }
+}
+
+template <typename config>
+void connection<config>::write_frame() {
+    //m_alog->write(log::alevel::devel,"connection write_frame");
+
+    {
+        scoped_lock_type lock(m_write_lock);
+
+        // Check the write flag. If true, there is an outstanding transport
+        // write already. In this case we just return. The write handler will
+        // start a new write if the write queue isn't empty. If false, we set
+        // the write flag and proceed to initiate a transport write.
+        if (m_write_flag) {
+            return;
+        }
+
+        // pull off all the messages that are ready to write.
+        // stop if we get a message marked terminal
+        message_ptr next_message = write_pop();
+        while (next_message) {
+            m_current_msgs.push_back(next_message);
+            if (!next_message->get_terminal()) {
+                next_message = write_pop();
+            } else {
+                next_message = message_ptr();
+            }
+        }
+        
+        if (m_current_msgs.empty()) {
+            // there was nothing to send
+            return;
+        } else {
+            // At this point we own the next messages to be sent and are
+            // responsible for holding the write flag until they are 
+            // successfully sent or there is some error
+            m_write_flag = true;
+        }
+    }
+
+    typename std::vector<message_ptr>::iterator it;
+    for (it = m_current_msgs.begin(); it != m_current_msgs.end(); ++it) {
+        std::string const & header = (*it)->get_header();
+        std::string const & payload = (*it)->get_payload();
+
+        m_send_buffer.push_back(transport::buffer(header.c_str(),header.size()));
+        m_send_buffer.push_back(transport::buffer(payload.c_str(),payload.size()));   
+    }
+
+    // Print detailed send stats if those log levels are enabled
+    if (m_alog->static_test(log::alevel::frame_header)) {
+    if (m_alog->dynamic_test(log::alevel::frame_header)) {
+        std::stringstream general,header,payload;
+        
+        general << "Dispatching write containing " << m_current_msgs.size()
+                <<" message(s) containing ";
+        header << "Header Bytes: \n";
+        payload << "Payload Bytes: \n";
+        
+        size_t hbytes = 0;
+        size_t pbytes = 0;
+        
+        for (size_t i = 0; i < m_current_msgs.size(); i++) {
+            hbytes += m_current_msgs[i]->get_header().size();
+            pbytes += m_current_msgs[i]->get_payload().size();
+
+            
+            header << "[" << i << "] (" 
+                   << m_current_msgs[i]->get_header().size() << ") " 
+                   << utility::to_hex(m_current_msgs[i]->get_header()) << "\n";
+
+            if (m_alog->static_test(log::alevel::frame_payload)) {
+            if (m_alog->dynamic_test(log::alevel::frame_payload)) {
+                payload << "[" << i << "] (" 
+                        << m_current_msgs[i]->get_payload().size() << ") ["<<m_current_msgs[i]->get_opcode()<<"] "
+                        << (m_current_msgs[i]->get_opcode() == frame::opcode::text ? 
+                                m_current_msgs[i]->get_payload() : 
+                                utility::to_hex(m_current_msgs[i]->get_payload())
+                           ) 
+                        << "\n";
+            }
+            }  
+        }
+        
+        general << hbytes << " header bytes and " << pbytes << " payload bytes";
+        
+        m_alog->write(log::alevel::frame_header,general.str());
+        m_alog->write(log::alevel::frame_header,header.str());
+        m_alog->write(log::alevel::frame_payload,payload.str());
+    }
+    }
+
+    transport_con_type::async_write(
+        m_send_buffer,
+        m_write_frame_handler
+    );
+}
+
+template <typename config>
+void connection<config>::handle_write_frame(lib::error_code const & ec)
+{
+    if (m_alog->static_test(log::alevel::devel)) {
+        m_alog->write(log::alevel::devel,"connection handle_write_frame");
+    }
+
+    bool terminal = m_current_msgs.back()->get_terminal();
+
+    m_send_buffer.clear();
+    m_current_msgs.clear();
+    // TODO: recycle instead of deleting
+
+    if (ec) {
+        log_err(log::elevel::fatal,"handle_write_frame",ec);
+        this->terminate(ec);
+        return;
+    }
+
+    if (terminal) {
+        this->terminate(lib::error_code());
+        return;
+    }
+
+    bool needs_writing = false;
+    {
+        scoped_lock_type lock(m_write_lock);
+
+        // release write flag
+        m_write_flag = false;
+
+        needs_writing = !m_send_queue.empty();
+    }
+
+    if (needs_writing) {
+        transport_con_type::dispatch(lib::bind(
+            &type::write_frame,
+            type::get_shared()
+        ));
+    }
+}
+
+template <typename config>
+std::vector<int> const & connection<config>::get_supported_versions() const
+{
+    return versions_supported;
+}
+
+template <typename config>
+void connection<config>::process_control_frame(typename config::message_type::ptr msg)
+{
+    m_alog->write(log::alevel::devel,"process_control_frame");
+
+    frame::opcode::value op = msg->get_opcode();
+    lib::error_code ec;
+
+    std::stringstream s;
+    s << "Control frame received with opcode " << op;
+    m_alog->write(log::alevel::control,s.str());
+
+    if (m_state == session::state::closed) {
+        m_elog->write(log::elevel::warn,"got frame in state closed");
+        return;
+    }
+    if (op != frame::opcode::CLOSE && m_state != session::state::open) {
+        m_elog->write(log::elevel::warn,"got non-close frame in state closing");
+        return;
+    }
+
+    if (op == frame::opcode::PING) {
+        bool should_reply = true;
+
+        if (m_ping_handler) {
+            should_reply = m_ping_handler(m_connection_hdl, msg->get_payload());
+        }
+
+        if (should_reply) {
+            this->pong(msg->get_payload(),ec);
+            if (ec) {
+                log_err(log::elevel::devel,"Failed to send response pong",ec);
+            }
+        }
+    } else if (op == frame::opcode::PONG) {
+        if (m_pong_handler) {
+            m_pong_handler(m_connection_hdl, msg->get_payload());
+        }
+        if (m_ping_timer) {
+            m_ping_timer->cancel();
+        }
+    } else if (op == frame::opcode::CLOSE) {
+        m_alog->write(log::alevel::devel,"got close frame");
+        // record close code and reason somewhere
+
+        m_remote_close_code = close::extract_code(msg->get_payload(),ec);
+        if (ec) {
+            s.str("");
+            if (config::drop_on_protocol_error) {
+                s << "Received invalid close code " << m_remote_close_code
+                  << " dropping connection per config.";
+                m_elog->write(log::elevel::devel,s.str());
+                this->terminate(ec);
+            } else {
+                s << "Received invalid close code " << m_remote_close_code
+                  << " sending acknowledgement and closing";
+                m_elog->write(log::elevel::devel,s.str());
+                ec = send_close_ack(close::status::protocol_error,
+                    "Invalid close code");
+                if (ec) {
+                    log_err(log::elevel::devel,"send_close_ack",ec);
+                }
+            }
+            return;
+        }
+
+        m_remote_close_reason = close::extract_reason(msg->get_payload(),ec);
+        if (ec) {
+            if (config::drop_on_protocol_error) {
+                m_elog->write(log::elevel::devel,
+                    "Received invalid close reason. Dropping connection per config");
+                this->terminate(ec);
+            } else {
+                m_elog->write(log::elevel::devel,
+                    "Received invalid close reason. Sending acknowledgement and closing");
+                ec = send_close_ack(close::status::protocol_error,
+                    "Invalid close reason");
+                if (ec) {
+                    log_err(log::elevel::devel,"send_close_ack",ec);
+                }
+            }
+            return;
+        }
+
+        if (m_state == session::state::open) {
+            s.str("");
+            s << "Received close frame with code " << m_remote_close_code
+              << " and reason " << m_remote_close_reason;
+            m_alog->write(log::alevel::devel,s.str());
+
+            ec = send_close_ack();
+            if (ec) {
+                log_err(log::elevel::devel,"send_close_ack",ec);
+            }
+        } else if (m_state == session::state::closing && !m_was_clean) {
+            // ack of our close
+            m_alog->write(log::alevel::devel, "Got acknowledgement of close");
+
+            m_was_clean = true;
+
+            // If we are a server terminate the connection now. Clients should
+            // leave the connection open to give the server an opportunity to
+            // initiate the TCP close. The client's timer will handle closing
+            // its side of the connection if the server misbehaves.
+            //
+            // TODO: different behavior if the underlying transport doesn't
+            // support timers?
+            if (m_is_server) {
+                terminate(lib::error_code());
+            }
+        } else {
+            // spurious, ignore
+            m_elog->write(log::elevel::devel, "Got close frame in wrong state");
+        }
+    } else {
+        // got an invalid control opcode
+        m_elog->write(log::elevel::devel, "Got control frame with invalid opcode");
+        // initiate protocol error shutdown
+    }
+}
+
+template <typename config>
+lib::error_code connection<config>::send_close_ack(close::status::value code,
+    std::string const & reason)
+{
+    return send_close_frame(code,reason,true,m_is_server);
+}
+
+template <typename config>
+lib::error_code connection<config>::send_close_frame(close::status::value code,
+    std::string const & reason, bool ack, bool terminal)
+{
+    m_alog->write(log::alevel::devel,"send_close_frame");
+
+    // check for special codes
+
+    // If silent close is set, respect it and blank out close information
+    // Otherwise use whatever has been specified in the parameters. If
+    // parameters specifies close::status::blank then determine what to do
+    // based on whether or not this is an ack. If it is not an ack just
+    // send blank info. If it is an ack then echo the close information from
+    // the remote endpoint.
+    if (config::silent_close) {
+        m_alog->write(log::alevel::devel,"closing silently");
+        m_local_close_code = close::status::no_status;
+        m_local_close_reason.clear();
+    } else if (code != close::status::blank) {
+        m_alog->write(log::alevel::devel,"closing with specified codes");
+        m_local_close_code = code;
+        m_local_close_reason = reason;
+    } else if (!ack) {
+        m_alog->write(log::alevel::devel,"closing with no status code");
+        m_local_close_code = close::status::no_status;
+        m_local_close_reason.clear();
+    } else if (m_remote_close_code == close::status::no_status) {
+        m_alog->write(log::alevel::devel,
+            "acknowledging a no-status close with normal code");
+        m_local_close_code = close::status::normal;
+        m_local_close_reason.clear();
+    } else {
+        m_alog->write(log::alevel::devel,"acknowledging with remote codes");
+        m_local_close_code = m_remote_close_code;
+        m_local_close_reason = m_remote_close_reason;
+    }
+
+    std::stringstream s;
+    s << "Closing with code: " << m_local_close_code << ", and reason: "
+      << m_local_close_reason;
+    m_alog->write(log::alevel::devel,s.str());
+
+    message_ptr msg = m_msg_manager->get_message();
+    if (!msg) {
+        return error::make_error_code(error::no_outgoing_buffers);
+    }
+
+    lib::error_code ec = m_processor->prepare_close(m_local_close_code,
+        m_local_close_reason,msg);
+    if (ec) {
+        return ec;
+    }
+
+    // Messages flagged terminal will result in the TCP connection being dropped
+    // after the message has been written. This is typically used when servers
+    // send an ack and when any endpoint encounters a protocol error
+    if (terminal) {
+        msg->set_terminal(true);
+    }
+
+    m_state = session::state::closing;
+
+    if (ack) {
+        m_was_clean = true;
+    }
+
+    // Start a timer so we don't wait forever for the acknowledgement close
+    // frame
+    if (m_close_handshake_timeout_dur > 0) {
+        m_handshake_timer = transport_con_type::set_timer(
+            m_close_handshake_timeout_dur,
+            lib::bind(
+                &type::handle_close_handshake_timeout,
+                type::get_shared(),
+                lib::placeholders::_1
+            )
+        );
+    }
+
+    bool needs_writing = false;
+    {
+        scoped_lock_type lock(m_write_lock);
+        write_push(msg);
+        needs_writing = !m_write_flag && !m_send_queue.empty();
+    }
+
+    if (needs_writing) {
+        transport_con_type::dispatch(lib::bind(
+            &type::write_frame,
+            type::get_shared()
+        ));
+    }
+
+    return lib::error_code();
+}
+
+template <typename config>
+typename connection<config>::processor_ptr
+connection<config>::get_processor(int version) const {
+    // TODO: allow disabling certain versions
+    
+    processor_ptr p;
+    
+    switch (version) {
+        case 0:
+            p = lib::make_shared<processor::hybi00<config> >(
+                transport_con_type::is_secure(),
+                m_is_server,
+                m_msg_manager
+            );
+            break;
+        case 7:
+            p = lib::make_shared<processor::hybi07<config> >(
+                transport_con_type::is_secure(),
+                m_is_server,
+                m_msg_manager,
+                lib::ref(m_rng)
+            );
+            break;
+        case 8:
+            p = lib::make_shared<processor::hybi08<config> >(
+                transport_con_type::is_secure(),
+                m_is_server,
+                m_msg_manager,
+                lib::ref(m_rng)
+            );
+            break;
+        case 13:
+            p = lib::make_shared<processor::hybi13<config> >(
+                transport_con_type::is_secure(),
+                m_is_server,
+                m_msg_manager,
+                lib::ref(m_rng)
+            );
+            break;
+        default:
+            return p;
+    }
+    
+    // Settings not configured by the constructor
+    p->set_max_message_size(m_max_message_size);
+    
+    return p;
+}
+
+template <typename config>
+void connection<config>::write_push(typename config::message_type::ptr msg)
+{
+    if (!msg) {
+        return;
+    }
+
+    m_send_buffer_size += msg->get_payload().size();
+    m_send_queue.push(msg);
+
+    if (m_alog->static_test(log::alevel::devel)) {
+        std::stringstream s;
+        s << "write_push: message count: " << m_send_queue.size()
+          << " buffer size: " << m_send_buffer_size;
+        m_alog->write(log::alevel::devel,s.str());
+    }
+}
+
+template <typename config>
+typename config::message_type::ptr connection<config>::write_pop()
+{
+    message_ptr msg;
+
+    if (m_send_queue.empty()) {
+        return msg;
+    }
+
+    msg = m_send_queue.front();
+
+    m_send_buffer_size -= msg->get_payload().size();
+    m_send_queue.pop();
+
+    if (m_alog->static_test(log::alevel::devel)) {
+        std::stringstream s;
+        s << "write_pop: message count: " << m_send_queue.size()
+          << " buffer size: " << m_send_buffer_size;
+        m_alog->write(log::alevel::devel,s.str());
+    }
+    return msg;
+}
+
+template <typename config>
+void connection<config>::log_open_result()
+{
+    std::stringstream s;
+
+    int version;
+    if (!processor::is_websocket_handshake(m_request)) {
+        version = -1;
+    } else {
+        version = processor::get_websocket_version(m_request);
+    }
+
+    // Connection Type
+    s << (version == -1 ? "HTTP" : "WebSocket") << " Connection ";
+
+    // Remote endpoint address
+    s << transport_con_type::get_remote_endpoint() << " ";
+
+    // Version string if WebSocket
+    if (version != -1) {
+        s << "v" << version << " ";
+    }
+
+    // User Agent
+    std::string ua = m_request.get_header("User-Agent");
+    if (ua.empty()) {
+        s << "\"\" ";
+    } else {
+        // check if there are any quotes in the user agent
+        s << "\"" << utility::string_replace_all(ua,"\"","\\\"") << "\" ";
+    }
+
+    // URI
+    s << (m_uri ? m_uri->get_resource() : "NULL") << " ";
+
+    // Status code
+    s << m_response.get_status_code();
+
+    m_alog->write(log::alevel::connect,s.str());
+}
+
+template <typename config>
+void connection<config>::log_close_result()
+{
+    std::stringstream s;
+
+    s << "Disconnect "
+      << "close local:[" << m_local_close_code
+      << (m_local_close_reason.empty() ? "" : ","+m_local_close_reason)
+      << "] remote:[" << m_remote_close_code
+      << (m_remote_close_reason.empty() ? "" : ","+m_remote_close_reason) << "]";
+
+    m_alog->write(log::alevel::disconnect,s.str());
+}
+
+template <typename config>
+void connection<config>::log_fail_result()
+{
+    std::stringstream s;
+    
+    int version = processor::get_websocket_version(m_request);
+
+    // Connection Type
+    s << "WebSocket Connection ";
+
+    // Remote endpoint address & WebSocket version
+    s << transport_con_type::get_remote_endpoint();
+    if (version < 0) {
+        s << " -";
+    } else {
+        s << " v" << version;
+    }
+
+    // User Agent
+    std::string ua = m_request.get_header("User-Agent");
+    if (ua.empty()) {
+        s << " \"\" ";
+    } else {
+        // check if there are any quotes in the user agent
+        s << " \"" << utility::string_replace_all(ua,"\"","\\\"") << "\" ";
+    }
+
+    // URI
+    s << (m_uri ? m_uri->get_resource() : "-");
+
+    // HTTP Status code
+    s  << " " << m_response.get_status_code();
+    
+    // WebSocket++ error code & reason
+    s << " " << m_ec << " " << m_ec.message();
+
+    m_alog->write(log::alevel::fail,s.str());
+}
+
+template <typename config>
+void connection<config>::log_http_result() {
+    std::stringstream s;
+
+    if (processor::is_websocket_handshake(m_request)) {
+        m_alog->write(log::alevel::devel,"Call to log_http_result for WebSocket");
+        return;
+    }  
+
+    // Connection Type
+    s << (m_request.get_header("host").empty() ? "-" : m_request.get_header("host"))
+      << " " << transport_con_type::get_remote_endpoint()
+      << " \"" << m_request.get_method() 
+      << " " << (m_uri ? m_uri->get_resource() : "-") 
+      << " " << m_request.get_version() << "\" " << m_response.get_status_code()
+      << " " << m_response.get_body().size();
+    
+    // User Agent
+    std::string ua = m_request.get_header("User-Agent");
+    if (ua.empty()) {
+        s << " \"\" ";
+    } else {
+        // check if there are any quotes in the user agent
+        s << " \"" << utility::string_replace_all(ua,"\"","\\\"") << "\" ";
+    }
+
+    m_alog->write(log::alevel::http,s.str());
+}
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_CONNECTION_IMPL_HPP
diff --git a/subprojects/websocketpp/websocketpp/impl/endpoint_impl.hpp b/subprojects/websocketpp/websocketpp/impl/endpoint_impl.hpp
new file mode 100644
index 000000000..2aac1d9da
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/impl/endpoint_impl.hpp
@@ -0,0 +1,269 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_ENDPOINT_IMPL_HPP
+#define WEBSOCKETPP_ENDPOINT_IMPL_HPP
+
+#include <string>
+
+namespace websocketpp {
+
+template <typename connection, typename config>
+typename endpoint<connection,config>::connection_ptr
+endpoint<connection,config>::create_connection() {
+    m_alog->write(log::alevel::devel,"create_connection");
+    //scoped_lock_type lock(m_state_lock);
+
+    /*if (m_state == STOPPING || m_state == STOPPED) {
+        return connection_ptr();
+    }*/
+
+    //scoped_lock_type guard(m_mutex);
+    // Create a connection on the heap and manage it using a shared pointer
+    connection_ptr con = lib::make_shared<connection_type>(m_is_server,
+        m_user_agent, m_alog, m_elog, lib::ref(m_rng));
+
+    connection_weak_ptr w(con);
+
+    // Create a weak pointer on the heap using that shared_ptr.
+    // Cast that weak pointer to void* and manage it using another shared_ptr
+    // connection_hdl hdl(reinterpret_cast<void*>(new connection_weak_ptr(con)));
+
+    con->set_handle(w);
+
+    // Copy default handlers from the endpoint
+    con->set_open_handler(m_open_handler);
+    con->set_close_handler(m_close_handler);
+    con->set_fail_handler(m_fail_handler);
+    con->set_ping_handler(m_ping_handler);
+    con->set_pong_handler(m_pong_handler);
+    con->set_pong_timeout_handler(m_pong_timeout_handler);
+    con->set_interrupt_handler(m_interrupt_handler);
+    con->set_http_handler(m_http_handler);
+    con->set_validate_handler(m_validate_handler);
+    con->set_message_handler(m_message_handler);
+
+    if (m_open_handshake_timeout_dur != config::timeout_open_handshake) {
+        con->set_open_handshake_timeout(m_open_handshake_timeout_dur);
+    }
+    if (m_close_handshake_timeout_dur != config::timeout_close_handshake) {
+        con->set_close_handshake_timeout(m_close_handshake_timeout_dur);
+    }
+    if (m_pong_timeout_dur != config::timeout_pong) {
+        con->set_pong_timeout(m_pong_timeout_dur);
+    }
+    if (m_max_message_size != config::max_message_size) {
+        con->set_max_message_size(m_max_message_size);
+    }
+    con->set_max_http_body_size(m_max_http_body_size);
+
+    lib::error_code ec;
+
+    ec = transport_type::init(con);
+    if (ec) {
+        m_elog->write(log::elevel::fatal,ec.message());
+        return connection_ptr();
+    }
+
+    return con;
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::interrupt(connection_hdl hdl, lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+
+    m_alog->write(log::alevel::devel,"Interrupting connection");
+
+    ec = con->interrupt();
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::interrupt(connection_hdl hdl) {
+    lib::error_code ec;
+    interrupt(hdl,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::pause_reading(connection_hdl hdl, lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+
+    ec = con->pause_reading();
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::pause_reading(connection_hdl hdl) {
+    lib::error_code ec;
+    pause_reading(hdl,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::resume_reading(connection_hdl hdl, lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+
+    ec = con->resume_reading();
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::resume_reading(connection_hdl hdl) {
+    lib::error_code ec;
+    resume_reading(hdl,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send_http_response(connection_hdl hdl,
+    lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+    con->send_http_response(ec);
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send_http_response(connection_hdl hdl) {
+    lib::error_code ec;
+    send_http_response(hdl,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send(connection_hdl hdl, std::string const & payload,
+    frame::opcode::value op, lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+
+    ec = con->send(payload,op);
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send(connection_hdl hdl, std::string const & payload,
+    frame::opcode::value op)
+{
+    lib::error_code ec;
+    send(hdl,payload,op,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send(connection_hdl hdl, void const * payload,
+    size_t len, frame::opcode::value op, lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+    ec = con->send(payload,len,op);
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send(connection_hdl hdl, void const * payload,
+    size_t len, frame::opcode::value op)
+{
+    lib::error_code ec;
+    send(hdl,payload,len,op,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send(connection_hdl hdl, message_ptr msg,
+    lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+    ec = con->send(msg);
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::send(connection_hdl hdl, message_ptr msg) {
+    lib::error_code ec;
+    send(hdl,msg,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::close(connection_hdl hdl, close::status::value
+    const code, std::string const & reason,
+    lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+    con->close(code,reason,ec);
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::close(connection_hdl hdl, close::status::value
+    const code, std::string const & reason)
+{
+    lib::error_code ec;
+    close(hdl,code,reason,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::ping(connection_hdl hdl, std::string const &
+    payload, lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+    con->ping(payload,ec);
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::ping(connection_hdl hdl, std::string const & payload)
+{
+    lib::error_code ec;
+    ping(hdl,payload,ec);
+    if (ec) { throw exception(ec); }
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::pong(connection_hdl hdl, std::string const & payload,
+    lib::error_code & ec)
+{
+    connection_ptr con = get_con_from_hdl(hdl,ec);
+    if (ec) {return;}
+    con->pong(payload,ec);
+}
+
+template <typename connection, typename config>
+void endpoint<connection,config>::pong(connection_hdl hdl, std::string const & payload)
+{
+    lib::error_code ec;
+    pong(hdl,payload,ec);
+    if (ec) { throw exception(ec); }
+}
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_ENDPOINT_IMPL_HPP
diff --git a/subprojects/websocketpp/websocketpp/impl/utilities_impl.hpp b/subprojects/websocketpp/websocketpp/impl/utilities_impl.hpp
new file mode 100644
index 000000000..6f86e22f5
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/impl/utilities_impl.hpp
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_UTILITIES_IMPL_HPP
+#define WEBSOCKETPP_UTILITIES_IMPL_HPP
+
+#include <algorithm>
+#include <string>
+
+namespace websocketpp {
+namespace utility {
+
+inline std::string to_lower(std::string const & in) {
+    std::string out = in;
+    std::transform(out.begin(),out.end(),out.begin(),::tolower);
+    return out;
+}
+
+inline std::string to_hex(std::string const & input) {
+    std::string output;
+    std::string hex = "0123456789ABCDEF";
+
+    for (size_t i = 0; i < input.size(); i++) {
+        output += hex[(input[i] & 0xF0) >> 4];
+        output += hex[input[i] & 0x0F];
+        output += " ";
+    }
+
+    return output;
+}
+
+inline std::string to_hex(uint8_t const * input, size_t length) {
+    std::string output;
+    std::string hex = "0123456789ABCDEF";
+
+    for (size_t i = 0; i < length; i++) {
+        output += hex[(input[i] & 0xF0) >> 4];
+        output += hex[input[i] & 0x0F];
+        output += " ";
+    }
+
+    return output;
+}
+
+inline std::string to_hex(const char* input,size_t length) {
+    return to_hex(reinterpret_cast<const uint8_t*>(input),length);
+}
+
+inline std::string string_replace_all(std::string subject, std::string const &
+    search, std::string const & replace)
+{
+    size_t pos = 0;
+    while((pos = subject.find(search, pos)) != std::string::npos) {
+         subject.replace(pos, search.length(), replace);
+         pos += replace.length();
+    }
+    return subject;
+}
+
+} // namespace utility
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_UTILITIES_IMPL_HPP
diff --git a/subprojects/websocketpp/websocketpp/logger/basic.hpp b/subprojects/websocketpp/websocketpp/logger/basic.hpp
new file mode 100644
index 000000000..84514130e
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/logger/basic.hpp
@@ -0,0 +1,199 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_LOGGER_BASIC_HPP
+#define WEBSOCKETPP_LOGGER_BASIC_HPP
+
+/* Need a way to print a message to the log
+ *
+ * - timestamps
+ * - channels
+ * - thread safe
+ * - output to stdout or file
+ * - selective output channels, both compile time and runtime
+ * - named channels
+ * - ability to test whether a log message will be printed at compile time
+ *
+ */
+
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/stdint.hpp>
+#include <websocketpp/common/time.hpp>
+
+#include <ctime>
+#include <iostream>
+#include <iomanip>
+#include <string>
+
+namespace websocketpp {
+namespace log {
+
+/// Basic logger that outputs to an ostream
+template <typename concurrency, typename names>
+class basic {
+public:
+    basic<concurrency,names>(channel_type_hint::value h =
+        channel_type_hint::access)
+      : m_static_channels(0xffffffff)
+      , m_dynamic_channels(0)
+      , m_out(h == channel_type_hint::error ? &std::cerr : &std::cout) {}
+
+    basic<concurrency,names>(std::ostream * out)
+      : m_static_channels(0xffffffff)
+      , m_dynamic_channels(0)
+      , m_out(out) {}
+
+    basic<concurrency,names>(level c, channel_type_hint::value h =
+        channel_type_hint::access)
+      : m_static_channels(c)
+      , m_dynamic_channels(0)
+      , m_out(h == channel_type_hint::error ? &std::cerr : &std::cout) {}
+
+    basic<concurrency,names>(level c, std::ostream * out)
+      : m_static_channels(c)
+      , m_dynamic_channels(0)
+      , m_out(out) {}
+
+    /// Destructor
+    ~basic<concurrency,names>() {}
+
+    /// Copy constructor
+    basic<concurrency,names>(basic<concurrency,names> const & other)
+     : m_static_channels(other.m_static_channels)
+     , m_dynamic_channels(other.m_dynamic_channels)
+     , m_out(other.m_out)
+    {}
+    
+#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+    // no copy assignment operator because of const member variables
+    basic<concurrency,names> & operator=(basic<concurrency,names> const &) = delete;
+#endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+
+#ifdef _WEBSOCKETPP_MOVE_SEMANTICS_
+    /// Move constructor
+    basic<concurrency,names>(basic<concurrency,names> && other)
+     : m_static_channels(other.m_static_channels)
+     , m_dynamic_channels(other.m_dynamic_channels)
+     , m_out(other.m_out)
+    {}
+
+#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+    // no move assignment operator because of const member variables
+    basic<concurrency,names> & operator=(basic<concurrency,names> &&) = delete;
+#endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+
+#endif // _WEBSOCKETPP_MOVE_SEMANTICS_
+
+    void set_ostream(std::ostream * out = &std::cout) {
+        m_out = out;
+    }
+
+    void set_channels(level channels) {
+        if (channels == names::none) {
+            clear_channels(names::all);
+            return;
+        }
+
+        scoped_lock_type lock(m_lock);
+        m_dynamic_channels |= (channels & m_static_channels);
+    }
+
+    void clear_channels(level channels) {
+        scoped_lock_type lock(m_lock);
+        m_dynamic_channels &= ~channels;
+    }
+
+    /// Write a string message to the given channel
+    /**
+     * @param channel The channel to write to
+     * @param msg The message to write
+     */
+    void write(level channel, std::string const & msg) {
+        scoped_lock_type lock(m_lock);
+        if (!this->dynamic_test(channel)) { return; }
+        *m_out << "[" << timestamp << "] "
+                  << "[" << names::channel_name(channel) << "] "
+                  << msg << "\n";
+        m_out->flush();
+    }
+
+    /// Write a cstring message to the given channel
+    /**
+     * @param channel The channel to write to
+     * @param msg The message to write
+     */
+    void write(level channel, char const * msg) {
+        scoped_lock_type lock(m_lock);
+        if (!this->dynamic_test(channel)) { return; }
+        *m_out << "[" << timestamp << "] "
+                  << "[" << names::channel_name(channel) << "] "
+                  << msg << "\n";
+        m_out->flush();
+    }
+
+    _WEBSOCKETPP_CONSTEXPR_TOKEN_ bool static_test(level channel) const {
+        return ((channel & m_static_channels) != 0);
+    }
+
+    bool dynamic_test(level channel) {
+        return ((channel & m_dynamic_channels) != 0);
+    }
+
+protected:
+    typedef typename concurrency::scoped_lock_type scoped_lock_type;
+    typedef typename concurrency::mutex_type mutex_type;
+    mutex_type m_lock;
+
+private:
+    // The timestamp does not include the time zone, because on Windows with the
+    // default registry settings, the time zone would be written out in full,
+    // which would be obnoxiously verbose.
+    //
+    // TODO: find a workaround for this or make this format user settable
+    static std::ostream & timestamp(std::ostream & os) {
+        std::time_t t = std::time(NULL);
+        std::tm lt = lib::localtime(t);
+        #ifdef _WEBSOCKETPP_PUTTIME_
+            return os << std::put_time(&lt,"%Y-%m-%d %H:%M:%S");
+        #else // Falls back to strftime, which requires a temporary copy of the string.
+            char buffer[20];
+            size_t result = std::strftime(buffer,sizeof(buffer),"%Y-%m-%d %H:%M:%S",&lt);
+            return os << (result == 0 ? "Unknown" : buffer);
+        #endif
+    }
+
+    level const m_static_channels;
+    level m_dynamic_channels;
+    std::ostream * m_out;
+};
+
+} // log
+} // websocketpp
+
+#endif // WEBSOCKETPP_LOGGER_BASIC_HPP
diff --git a/subprojects/websocketpp/websocketpp/logger/levels.hpp b/subprojects/websocketpp/websocketpp/logger/levels.hpp
new file mode 100644
index 000000000..cd7ccd690
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/logger/levels.hpp
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_LOGGER_LEVELS_HPP
+#define WEBSOCKETPP_LOGGER_LEVELS_HPP
+
+#include <websocketpp/common/stdint.hpp>
+
+namespace websocketpp {
+namespace log {
+
+/// Type of a channel package
+typedef uint32_t level;
+
+/// Package of values for hinting at the nature of a given logger.
+/**
+ * Used by the library to signal to the logging class a hint that it can use to
+ * set itself up. For example, the `access` hint indicates that it is an access
+ * log that might be suitable for being printed to an access log file or to cout
+ * whereas `error` might be suitable for an error log file or cerr. 
+ */
+struct channel_type_hint {
+    /// Type of a channel type hint value
+    typedef uint32_t value;
+    
+    /// No information
+    static value const none = 0;
+    /// Access log
+    static value const access = 1;
+    /// Error log
+    static value const error = 2;
+};
+
+/// Package of log levels for logging errors
+struct elevel {
+    /// Special aggregate value representing "no levels"
+    static level const none = 0x0;
+    /// Low level debugging information (warning: very chatty)
+    static level const devel = 0x1;
+    /// Information about unusual system states or other minor internal library
+    /// problems, less chatty than devel.
+    static level const library = 0x2;
+    /// Information about minor configuration problems or additional information
+    /// about other warnings.
+    static level const info = 0x4;
+    /// Information about important problems not severe enough to terminate
+    /// connections.
+    static level const warn = 0x8;
+    /// Recoverable error. Recovery may mean cleanly closing the connection with
+    /// an appropriate error code to the remote endpoint.
+    static level const rerror = 0x10;
+    /// Unrecoverable error. This error will trigger immediate unclean
+    /// termination of the connection or endpoint.
+    static level const fatal = 0x20;
+    /// Special aggregate value representing "all levels"
+    static level const all = 0xffffffff;
+
+    /// Get the textual name of a channel given a channel id
+    /**
+     * The id must be that of a single channel. Passing an aggregate channel
+     * package results in undefined behavior.
+     *
+     * @param channel The channel id to look up.
+     *
+     * @return The name of the specified channel.
+     */
+    static char const * channel_name(level channel) {
+        switch(channel) {
+            case devel:
+                return "devel";
+            case library:
+                return "library";
+            case info:
+                return "info";
+            case warn:
+                return "warning";
+            case rerror:
+                return "error";
+            case fatal:
+                return "fatal";
+            default:
+                return "unknown";
+        }
+    }
+};
+
+/// Package of log levels for logging access events
+struct alevel {
+    /// Special aggregate value representing "no levels"
+    static level const none = 0x0;
+    /// Information about new connections
+    /**
+     * One line for each new connection that includes a host of information
+     * including: the remote address, websocket version, requested resource,
+     * http code, remote user agent
+     */
+    static level const connect = 0x1;
+    /// One line for each closed connection. Includes closing codes and reasons.
+    static level const disconnect = 0x2;
+    /// One line per control frame
+    static level const control = 0x4;
+    /// One line per frame, includes the full frame header
+    static level const frame_header = 0x8;
+    /// One line per frame, includes the full message payload (warning: chatty)
+    static level const frame_payload = 0x10;
+    /// Reserved
+    static level const message_header = 0x20;
+    /// Reserved
+    static level const message_payload = 0x40;
+    /// Reserved
+    static level const endpoint = 0x80;
+    /// Extra information about opening handshakes
+    static level const debug_handshake = 0x100;
+    /// Extra information about closing handshakes
+    static level const debug_close = 0x200;
+    /// Development messages (warning: very chatty)
+    static level const devel = 0x400;
+    /// Special channel for application specific logs. Not used by the library.
+    static level const app = 0x800;
+    /// Access related to HTTP requests
+    static level const http = 0x1000;
+    /// One line for each failed WebSocket connection with details
+    static level const fail = 0x2000;
+    /// Aggregate package representing the commonly used core access channels
+    /// Connect, Disconnect, Fail, and HTTP
+    static level const access_core = 0x00003003;
+    /// Special aggregate value representing "all levels"
+    static level const all = 0xffffffff;
+
+    /// Get the textual name of a channel given a channel id
+    /**
+     * Get the textual name of a channel given a channel id. The id must be that
+     * of a single channel. Passing an aggregate channel package results in
+     * undefined behavior.
+     *
+     * @param channel The channelid to look up.
+     *
+     * @return The name of the specified channel.
+     */
+    static char const * channel_name(level channel) {
+        switch(channel) {
+            case connect:
+                return "connect";
+            case disconnect:
+                return "disconnect";
+            case control:
+                return "control";
+            case frame_header:
+                return "frame_header";
+            case frame_payload:
+                return "frame_payload";
+            case message_header:
+                return "message_header";
+            case message_payload:
+                return "message_payload";
+            case endpoint:
+                return "endpoint";
+            case debug_handshake:
+                return "debug_handshake";
+            case debug_close:
+                return "debug_close";
+            case devel:
+                return "devel";
+            case app:
+                return "application";
+            case http:
+                return "http";
+            case fail:
+                return "fail";
+            default:
+                return "unknown";
+        }
+    }
+};
+
+} // logger
+} // websocketpp
+
+#endif //WEBSOCKETPP_LOGGER_LEVELS_HPP
diff --git a/subprojects/websocketpp/websocketpp/logger/stub.hpp b/subprojects/websocketpp/websocketpp/logger/stub.hpp
new file mode 100644
index 000000000..2db6da7df
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/logger/stub.hpp
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_LOGGER_STUB_HPP
+#define WEBSOCKETPP_LOGGER_STUB_HPP
+
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/cpp11.hpp>
+
+#include <string>
+
+namespace websocketpp {
+namespace log {
+
+/// Stub logger that ignores all input
+class stub {
+public:
+    /// Construct the logger
+    /**
+     * @param hint A channel type specific hint for how to construct the logger
+     */
+    explicit stub(channel_type_hint::value) {}
+
+    /// Construct the logger
+    /**
+     * @param default_channels A set of channels to statically enable
+     * @param hint A channel type specific hint for how to construct the logger
+     */
+    stub(level, channel_type_hint::value) {}
+    _WEBSOCKETPP_CONSTEXPR_TOKEN_ stub() {}
+
+    /// Dynamically enable the given list of channels
+    /**
+     * All operations on the stub logger are no-ops and all arguments are
+     * ignored
+     *
+     * @param channels The package of channels to enable
+     */
+    void set_channels(level) {}
+
+    /// Dynamically disable the given list of channels
+    /**
+     * All operations on the stub logger are no-ops and all arguments are
+     * ignored
+     *
+     * @param channels The package of channels to disable
+     */
+    void clear_channels(level) {}
+
+    /// Write a string message to the given channel
+    /**
+     * Writing on the stub logger is a no-op and all arguments are ignored
+     *
+     * @param channel The channel to write to
+     * @param msg The message to write
+     */
+    void write(level, std::string const &) {}
+
+    /// Write a cstring message to the given channel
+    /**
+     * Writing on the stub logger is a no-op and all arguments are ignored
+     *
+     * @param channel The channel to write to
+     * @param msg The message to write
+     */
+    void write(level, char const *) {}
+
+    /// Test whether a channel is statically enabled
+    /**
+     * The stub logger has no channels so all arguments are ignored and
+     * `static_test` always returns false.
+     *
+     * @param channel The package of channels to test
+     */
+    _WEBSOCKETPP_CONSTEXPR_TOKEN_ bool static_test(level) const {
+        return false;
+    }
+
+    /// Test whether a channel is dynamically enabled
+    /**
+     * The stub logger has no channels so all arguments are ignored and
+     * `dynamic_test` always returns false.
+     *
+     * @param channel The package of channels to test
+     */
+    bool dynamic_test(level) {
+        return false;
+    }
+};
+
+} // log
+} // websocketpp
+
+#endif // WEBSOCKETPP_LOGGER_STUB_HPP
diff --git a/subprojects/websocketpp/websocketpp/logger/syslog.hpp b/subprojects/websocketpp/websocketpp/logger/syslog.hpp
new file mode 100644
index 000000000..513abee4a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/logger/syslog.hpp
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * The initial version of this logging policy was contributed to the WebSocket++
+ * project by Tom Hughes.
+ */
+
+#ifndef WEBSOCKETPP_LOGGER_SYSLOG_HPP
+#define WEBSOCKETPP_LOGGER_SYSLOG_HPP
+
+#include <syslog.h>
+
+#include <websocketpp/logger/basic.hpp>
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/logger/levels.hpp>
+
+namespace websocketpp {
+namespace log {
+
+/// Basic logger that outputs to syslog
+template <typename concurrency, typename names>
+class syslog : public basic<concurrency, names> {
+public:
+    typedef basic<concurrency, names> base;
+
+    /// Construct the logger
+    /**
+     * @param hint A channel type specific hint for how to construct the logger
+     */
+    syslog<concurrency,names>(channel_type_hint::value hint =
+        channel_type_hint::access)
+      : basic<concurrency,names>(hint), m_channel_type_hint(hint) {}
+
+    /// Construct the logger
+    /**
+     * @param channels A set of channels to statically enable
+     * @param hint A channel type specific hint for how to construct the logger
+     */
+    syslog<concurrency,names>(level channels, channel_type_hint::value hint =
+        channel_type_hint::access)
+      : basic<concurrency,names>(channels, hint), m_channel_type_hint(hint) {}
+
+    /// Write a string message to the given channel
+    /**
+     * @param channel The channel to write to
+     * @param msg The message to write
+     */
+    void write(level channel, std::string const & msg) {
+        write(channel, msg.c_str());
+    }
+
+    /// Write a cstring message to the given channel
+    /**
+     * @param channel The channel to write to
+     * @param msg The message to write
+     */
+    void write(level channel, char const * msg) {
+        scoped_lock_type lock(base::m_lock);
+        if (!this->dynamic_test(channel)) { return; }
+        ::syslog(syslog_priority(channel), "[%s] %s",
+            names::channel_name(channel), msg);
+    }
+private:
+    typedef typename base::scoped_lock_type scoped_lock_type;
+
+    /// The default level is used for all access logs and any error logs that
+    /// don't trivially map to one of the standard syslog levels.
+    static int const default_level = LOG_INFO;
+
+    /// retrieve the syslog priority code given a WebSocket++ channel
+    /**
+     * @param channel The level to look up
+     * @return The syslog level associated with `channel`
+     */
+    int syslog_priority(level channel) const {
+        if (m_channel_type_hint == channel_type_hint::access) {
+            return syslog_priority_access(channel);
+        } else {
+            return syslog_priority_error(channel);
+        }
+    }
+
+    /// retrieve the syslog priority code given a WebSocket++ error channel
+    /**
+     * @param channel The level to look up
+     * @return The syslog level associated with `channel`
+     */
+    int syslog_priority_error(level channel) const {
+        switch (channel) {
+            case elevel::devel:
+                return LOG_DEBUG;
+            case elevel::library:
+                return LOG_DEBUG;
+            case elevel::info:
+                return LOG_INFO;
+            case elevel::warn:
+                return LOG_WARNING;
+            case elevel::rerror:
+                return LOG_ERR;
+            case elevel::fatal:
+                return LOG_CRIT;
+            default:
+                return default_level;
+        }
+    }
+
+    /// retrieve the syslog priority code given a WebSocket++ access channel
+    /**
+     * @param channel The level to look up
+     * @return The syslog level associated with `channel`
+     */
+    _WEBSOCKETPP_CONSTEXPR_TOKEN_ int syslog_priority_access(level) const {
+        return default_level;
+    }
+
+    channel_type_hint::value m_channel_type_hint;
+};
+
+} // log
+} // websocketpp
+
+#endif // WEBSOCKETPP_LOGGER_SYSLOG_HPP
diff --git a/subprojects/websocketpp/websocketpp/message_buffer/alloc.hpp b/subprojects/websocketpp/websocketpp/message_buffer/alloc.hpp
new file mode 100644
index 000000000..75d89766a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/message_buffer/alloc.hpp
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP
+#define WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP
+
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/frame.hpp>
+
+namespace websocketpp {
+namespace message_buffer {
+namespace alloc {
+
+/// A connection message manager that allocates a new message for each
+/// request.
+template <typename message>
+class con_msg_manager
+  : public lib::enable_shared_from_this<con_msg_manager<message> >
+{
+public:
+    typedef con_msg_manager<message> type;
+    typedef lib::shared_ptr<con_msg_manager> ptr;
+    typedef lib::weak_ptr<con_msg_manager> weak_ptr;
+
+    typedef typename message::ptr message_ptr;
+
+    /// Get an empty message buffer
+    /**
+     * @return A shared pointer to an empty new message
+     */
+    message_ptr get_message() {
+        return message_ptr(lib::make_shared<message>(type::shared_from_this()));
+    }
+
+    /// Get a message buffer with specified size and opcode
+    /**
+     * @param op The opcode to use
+     * @param size Minimum size in bytes to request for the message payload.
+     *
+     * @return A shared pointer to a new message with specified size.
+     */
+    message_ptr get_message(frame::opcode::value op,size_t size) {
+        return message_ptr(lib::make_shared<message>(type::shared_from_this(),op,size));
+    }
+
+    /// Recycle a message
+    /**
+     * This method shouldn't be called. If it is, return false to indicate an
+     * error. The rest of the method recycle chain should notice this and free
+     * the memory.
+     *
+     * @param msg The message to be recycled.
+     *
+     * @return true if the message was successfully recycled, false otherwse.
+     */
+    bool recycle(message *) {
+        return false;
+    }
+};
+
+/// An endpoint message manager that allocates a new manager for each
+/// connection.
+template <typename con_msg_manager>
+class endpoint_msg_manager {
+public:
+    typedef typename con_msg_manager::ptr con_msg_man_ptr;
+
+    /// Get a pointer to a connection message manager
+    /**
+     * @return A pointer to the requested connection message manager.
+     */
+    con_msg_man_ptr get_manager() const {
+        return con_msg_man_ptr(lib::make_shared<con_msg_manager>());
+    }
+};
+
+} // namespace alloc
+} // namespace message_buffer
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP
diff --git a/subprojects/websocketpp/websocketpp/message_buffer/message.hpp b/subprojects/websocketpp/websocketpp/message_buffer/message.hpp
new file mode 100644
index 000000000..da36e2001
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/message_buffer/message.hpp
@@ -0,0 +1,340 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_MESSAGE_BUFFER_MESSAGE_HPP
+#define WEBSOCKETPP_MESSAGE_BUFFER_MESSAGE_HPP
+
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/frame.hpp>
+
+#include <string>
+
+namespace websocketpp {
+namespace message_buffer {
+
+/* # message:
+ * object that stores a message while it is being sent or received. Contains
+ * the message payload itself, the message header, the extension data, and the
+ * opcode.
+ *
+ * # connection_message_manager:
+ * An object that manages all of the message_buffers associated with a given
+ * connection. Implements the get_message_buffer(size) method that returns
+ * a message buffer at least size bytes long.
+ *
+ * Message buffers are reference counted with shared ownership semantics. Once
+ * requested from the manager the requester and it's associated downstream code
+ * may keep a pointer to the message indefinitely at a cost of extra resource
+ * usage. Once the reference count drops to the point where the manager is the
+ * only reference the messages is recycled using whatever method is implemented
+ * in the manager.
+ *
+ * # endpoint_message_manager:
+ * An object that manages connection_message_managers. Implements the
+ * get_message_manager() method. This is used once by each connection to
+ * request the message manager that they are supposed to use to manage message
+ * buffers for their own use.
+ *
+ * TYPES OF CONNECTION_MESSAGE_MANAGERS
+ * - allocate a message with the exact size every time one is requested
+ * - maintain a pool of pre-allocated messages and return one when needed.
+ *   Recycle previously used messages back into the pool
+ *
+ * TYPES OF ENDPOINT_MESSAGE_MANAGERS
+ *  - allocate a new connection manager for each connection. Message pools
+ *    become connection specific. This increases memory usage but improves
+ *    concurrency.
+ *  - allocate a single connection manager and share a pointer to it with all
+ *    connections created by this endpoint. The message pool will be shared
+ *    among all connections, improving memory usage and performance at the cost
+ *    of reduced concurrency
+ */
+
+
+/// Represents a buffer for a single WebSocket message.
+/**
+ *
+ *
+ */
+template <template<class> class con_msg_manager>
+class message {
+public:
+    typedef lib::shared_ptr<message> ptr;
+
+    typedef con_msg_manager<message> con_msg_man_type;
+    typedef typename con_msg_man_type::ptr con_msg_man_ptr;
+    typedef typename con_msg_man_type::weak_ptr con_msg_man_weak_ptr;
+
+    /// Construct an empty message
+    /**
+     * Construct an empty message
+     */
+    message(const con_msg_man_ptr manager)
+      : m_manager(manager)
+      , m_prepared(false)
+      , m_fin(true)
+      , m_terminal(false)
+      , m_compressed(false) {}
+
+    /// Construct a message and fill in some values
+    /**
+     *
+     */
+    message(const con_msg_man_ptr manager, frame::opcode::value op, size_t size = 128)
+      : m_manager(manager)
+      , m_opcode(op)
+      , m_prepared(false)
+      , m_fin(true)
+      , m_terminal(false)
+      , m_compressed(false)
+    {
+        m_payload.reserve(size);
+    }
+
+    /// Return whether or not the message has been prepared for sending
+    /**
+     * The prepared flag indicates that the message has been prepared by a
+     * websocket protocol processor and is ready to be written to the wire.
+     *
+     * @return whether or not the message has been prepared for sending
+     */
+    bool get_prepared() const {
+        return m_prepared;
+    }
+
+    /// Set or clear the flag that indicates that the message has been prepared
+    /**
+     * This flag should not be set by end user code without a very good reason.
+     *
+     * @param value The value to set the prepared flag to
+     */
+    void set_prepared(bool value) {
+        m_prepared = value;
+    }
+
+    /// Return whether or not the message is flagged as compressed
+    /**
+     * @return whether or not the message is/should be compressed
+     */
+    bool get_compressed() const {
+        return m_compressed;
+    }
+
+    /// Set or clear the compression flag
+    /**
+     * Setting the compression flag indicates that the data in this message
+     * would benefit from compression. If both endpoints negotiate a compression
+     * extension WebSocket++ will attempt to compress messages with this flag.
+     * Setting this flag does not guarantee that the message will be compressed.
+     *
+     * @param value The value to set the compressed flag to
+     */
+    void set_compressed(bool value) {
+        m_compressed = value;
+    }
+
+    /// Get whether or not the message is terminal
+    /**
+     * Messages can be flagged as terminal, which results in the connection
+     * being close after they are written rather than the implementation going
+     * on to the next message in the queue. This is typically used internally
+     * for close messages only.
+     *
+     * @return Whether or not this message is marked terminal
+     */
+    bool get_terminal() const {
+        return m_terminal;
+    }
+
+    /// Set the terminal flag
+    /**
+     * This flag should not be set by end user code without a very good reason.
+     *
+     * @see get_terminal()
+     *
+     * @param value The value to set the terminal flag to.
+     */
+    void set_terminal(bool value) {
+        m_terminal = value;
+    }
+    /// Read the fin bit
+    /**
+     * A message with the fin bit set will be sent as the last message of its
+     * sequence. A message with the fin bit cleared will require subsequent
+     * frames of opcode continuation until one of them has the fin bit set.
+     *
+     * The remote end likely will not deliver any bytes until the frame with the fin
+     * bit set has been received.
+     *
+     * @return Whether or not the fin bit is set
+     */
+    bool get_fin() const {
+        return m_fin;
+    }
+
+    /// Set the fin bit
+    /**
+     * @see get_fin for a more detailed explaination of the fin bit
+     *
+     * @param value The value to set the fin bit to.
+     */
+    void set_fin(bool value) {
+        m_fin = value;
+    }
+
+    /// Return the message opcode
+    frame::opcode::value get_opcode() const {
+        return m_opcode;
+    }
+
+    /// Set the opcode
+    void set_opcode(frame::opcode::value op) {
+        m_opcode = op;
+    }
+
+    /// Return the prepared frame header
+    /**
+     * This value is typically set by a websocket protocol processor
+     * and shouldn't be tampered with.
+     */
+    std::string const & get_header() const {
+        return m_header;
+    }
+
+    /// Set prepared frame header
+    /**
+     * Under normal circumstances this should not be called by end users
+     *
+     * @param header A string to set the header to.
+     */
+    void set_header(std::string const & header) {
+        m_header = header;
+    }
+
+    std::string const & get_extension_data() const {
+        return m_extension_data;
+    }
+
+    /// Get a reference to the payload string
+    /**
+     * @return A const reference to the message's payload string
+     */
+    std::string const & get_payload() const {
+        return m_payload;
+    }
+
+    /// Get a non-const reference to the payload string
+    /**
+     * @return A reference to the message's payload string
+     */
+    std::string & get_raw_payload() {
+        return m_payload;
+    }
+
+    /// Set payload data
+    /**
+     * Set the message buffer's payload to the given value.
+     *
+     * @param payload A string to set the payload to.
+     */
+    void set_payload(std::string const & payload) {
+        m_payload = payload;
+    }
+
+    /// Set payload data
+    /**
+     * Set the message buffer's payload to the given value.
+     *
+     * @param payload A pointer to a data array to set to.
+     * @param len The length of new payload in bytes.
+     */
+    void set_payload(void const * payload, size_t len) {
+        m_payload.reserve(len);
+        char const * pl = static_cast<char const *>(payload);
+        m_payload.assign(pl, pl + len);
+    }
+
+    /// Append payload data
+    /**
+     * Append data to the message buffer's payload.
+     *
+     * @param payload A string containing the data array to append.
+     */
+    void append_payload(std::string const & payload) {
+        m_payload.append(payload);
+    }
+
+    /// Append payload data
+    /**
+     * Append data to the message buffer's payload.
+     *
+     * @param payload A pointer to a data array to append
+     * @param len The length of payload in bytes
+     */
+    void append_payload(void const * payload, size_t len) {
+        m_payload.reserve(m_payload.size()+len);
+        m_payload.append(static_cast<char const *>(payload),len);
+    }
+
+    /// Recycle the message
+    /**
+     * A request to recycle this message was received. Forward that request to
+     * the connection message manager for processing. Errors and exceptions
+     * from the manager's recycle member function should be passed back up the
+     * call chain. The caller to message::recycle will deal with them.
+     *
+     * Recycle must *only* be called by the message shared_ptr's destructor.
+     * Once recycled successfully, ownership of the memory has been passed to
+     * another system and must not be accessed again.
+     *
+     * @return true if the message was successfully recycled, false otherwise.
+     */
+    bool recycle() {
+        con_msg_man_ptr shared = m_manager.lock();
+
+        if (shared) {
+            return shared->recycle(this);
+        } else {
+            return false;
+        }
+    }
+private:
+    con_msg_man_weak_ptr        m_manager;
+    std::string                 m_header;
+    std::string                 m_extension_data;
+    std::string                 m_payload;
+    frame::opcode::value        m_opcode;
+    bool                        m_prepared;
+    bool                        m_fin;
+    bool                        m_terminal;
+    bool                        m_compressed;
+};
+
+} // namespace message_buffer
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_MESSAGE_BUFFER_MESSAGE_HPP
diff --git a/subprojects/websocketpp/websocketpp/message_buffer/pool.hpp b/subprojects/websocketpp/websocketpp/message_buffer/pool.hpp
new file mode 100644
index 000000000..3af9e02a2
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/message_buffer/pool.hpp
@@ -0,0 +1,229 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP
+#define WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP
+
+#include <websocketpp/common/memory.hpp>
+
+#include <string>
+
+namespace websocketpp {
+namespace message_buffer {
+
+/* # message:
+ * object that stores a message while it is being sent or received. Contains
+ * the message payload itself, the message header, the extension data, and the
+ * opcode.
+ *
+ * # connection_message_manager:
+ * An object that manages all of the message_buffers associated with a given
+ * connection. Implements the get_message_buffer(size) method that returns
+ * a message buffer at least size bytes long.
+ *
+ * Message buffers are reference counted with shared ownership semantics. Once
+ * requested from the manager the requester and it's associated downstream code
+ * may keep a pointer to the message indefinitely at a cost of extra resource
+ * usage. Once the reference count drops to the point where the manager is the
+ * only reference the messages is recycled using whatever method is implemented
+ * in the manager.
+ *
+ * # endpoint_message_manager:
+ * An object that manages connection_message_managers. Implements the
+ * get_message_manager() method. This is used once by each connection to
+ * request the message manager that they are supposed to use to manage message
+ * buffers for their own use.
+ *
+ * TYPES OF CONNECTION_MESSAGE_MANAGERS
+ * - allocate a message with the exact size every time one is requested
+ * - maintain a pool of pre-allocated messages and return one when needed.
+ *   Recycle previously used messages back into the pool
+ *
+ * TYPES OF ENDPOINT_MESSAGE_MANAGERS
+ *  - allocate a new connection manager for each connection. Message pools
+ *    become connection specific. This increases memory usage but improves
+ *    concurrency.
+ *  - allocate a single connection manager and share a pointer to it with all
+ *    connections created by this endpoint. The message pool will be shared
+ *    among all connections, improving memory usage and performance at the cost
+ *    of reduced concurrency
+ */
+
+/// Custom deleter for use in shared_ptrs to message.
+/**
+ * This is used to catch messages about to be deleted and offer the manager the
+ * ability to recycle them instead. Message::recycle will return true if it was
+ * successfully recycled and false otherwise. In the case of exceptions or error
+ * this deleter frees the memory.
+ */
+template <typename T>
+void message_deleter(T* msg) {
+    try {
+        if (!msg->recycle()) {
+            delete msg;
+        }
+    } catch (...) {
+        // TODO: is there a better way to ensure this function doesn't throw?
+        delete msg;
+    }
+}
+
+/// Represents a buffer for a single WebSocket message.
+/**
+ *
+ *
+ */
+template <typename con_msg_manager>
+class message {
+public:
+    typedef lib::shared_ptr<message> ptr;
+
+    typedef typename con_msg_manager::weak_ptr con_msg_man_ptr;
+
+    message(con_msg_man_ptr manager, size_t size = 128)
+      : m_manager(manager)
+      , m_payload(size) {}
+
+    frame::opcode::value get_opcode() const {
+        return m_opcode;
+    }
+    const std::string& get_header() const {
+        return m_header;
+    }
+    const std::string& get_extension_data() const {
+        return m_extension_data;
+    }
+    const std::string& get_payload() const {
+        return m_payload;
+    }
+
+    /// Recycle the message
+    /**
+     * A request to recycle this message was received. Forward that request to
+     * the connection message manager for processing. Errors and exceptions
+     * from the manager's recycle member function should be passed back up the
+     * call chain. The caller to message::recycle will deal with them.
+     *
+     * Recycle must *only* be called by the message shared_ptr's destructor.
+     * Once recycled successfully, ownership of the memory has been passed to
+     * another system and must not be accessed again.
+     *
+     * @return true if the message was successfully recycled, false otherwise.
+     */
+    bool recycle() {
+        typename con_msg_manager::ptr shared = m_manager.lock();
+
+        if (shared) {
+            return shared->(recycle(this));
+        } else {
+            return false;
+        }
+    }
+private:
+    con_msg_man_ptr             m_manager;
+
+    frame::opcode::value        m_opcode;
+    std::string                 m_header;
+    std::string                 m_extension_data;
+    std::string                 m_payload;
+};
+
+namespace alloc {
+
+/// A connection message manager that allocates a new message for each
+/// request.
+template <typename message>
+class con_msg_manager {
+public:
+    typedef lib::shared_ptr<con_msg_manager> ptr;
+    typedef lib::weak_ptr<con_msg_manager> weak_ptr;
+
+    typedef typename message::ptr message_ptr;
+
+    /// Get a message buffer with specified size
+    /**
+     * @param size Minimum size in bytes to request for the message payload.
+     *
+     * @return A shared pointer to a new message with specified size.
+     */
+    message_ptr get_message(size_t size) const {
+        return lib::make_shared<message>(size);
+    }
+
+    /// Recycle a message
+    /**
+     * This method shouldn't be called. If it is, return false to indicate an
+     * error. The rest of the method recycle chain should notice this and free
+     * the memory.
+     *
+     * @param msg The message to be recycled.
+     *
+     * @return true if the message was successfully recycled, false otherwse.
+     */
+    bool recycle(message * msg) {
+        return false;
+    }
+};
+
+/// An endpoint message manager that allocates a new manager for each
+/// connection.
+template <typename con_msg_manager>
+class endpoint_msg_manager {
+public:
+    typedef typename con_msg_manager::ptr con_msg_man_ptr;
+
+    /// Get a pointer to a connection message manager
+    /**
+     * @return A pointer to the requested connection message manager.
+     */
+    con_msg_man_ptr get_manager() const {
+        return lib::make_shared<con_msg_manager>();
+    }
+};
+
+} // namespace alloc
+
+namespace pool {
+
+/// A connection messages manager that maintains a pool of messages that is
+/// used to fulfill get_message requests.
+class con_msg_manager {
+
+};
+
+/// An endpoint manager that maintains a shared pool of connection managers
+/// and returns an appropriate one for the requesting connection.
+class endpoint_msg_manager {
+
+};
+
+} // namespace pool
+
+} // namespace message_buffer
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_MESSAGE_BUFFER_ALLOC_HPP
diff --git a/subprojects/websocketpp/websocketpp/processors/base.hpp b/subprojects/websocketpp/websocketpp/processors/base.hpp
new file mode 100644
index 000000000..4c123dfab
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/processors/base.hpp
@@ -0,0 +1,299 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_PROCESSOR_BASE_HPP
+#define WEBSOCKETPP_PROCESSOR_BASE_HPP
+
+#include <websocketpp/close.hpp>
+#include <websocketpp/utilities.hpp>
+#include <websocketpp/uri.hpp>
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <string>
+
+namespace websocketpp {
+namespace processor {
+
+/// Constants related to processing WebSocket connections
+namespace constants {
+
+static char const upgrade_token[] = "websocket";
+static char const connection_token[] = "Upgrade";
+static char const handshake_guid[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+
+} // namespace constants
+
+
+/// Processor class related error codes
+namespace error_cat {
+enum value {
+    BAD_REQUEST = 0, // Error was the result of improperly formatted user input
+    INTERNAL_ERROR = 1, // Error was a logic error internal to WebSocket++
+    PROTOCOL_VIOLATION = 2,
+    MESSAGE_TOO_BIG = 3,
+    PAYLOAD_VIOLATION = 4 // Error was due to receiving invalid payload data
+};
+} // namespace error_cat
+
+/// Error code category and codes used by all processor types
+namespace error {
+enum processor_errors {
+    /// Catch-all error for processor policy errors that don't fit in other
+    /// categories
+    general = 1,
+
+    /// Error was the result of improperly formatted user input
+    bad_request,
+
+    /// Processor encountered a protocol violation in an incoming message
+    protocol_violation,
+
+    /// Processor encountered a message that was too large
+    message_too_big,
+
+    /// Processor encountered invalid payload data.
+    invalid_payload,
+
+    /// The processor method was called with invalid arguments
+    invalid_arguments,
+
+    /// Opcode was invalid for requested operation
+    invalid_opcode,
+
+    /// Control frame too large
+    control_too_big,
+
+    /// Illegal use of reserved bit
+    invalid_rsv_bit,
+
+    /// Fragmented control message
+    fragmented_control,
+
+    /// Continuation without message
+    invalid_continuation,
+
+    /// Clients may not send unmasked frames
+    masking_required,
+
+    /// Servers may not send masked frames
+    masking_forbidden,
+
+    /// Payload length not minimally encoded
+    non_minimal_encoding,
+
+    /// Not supported on 32 bit systems
+    requires_64bit,
+
+    /// Invalid UTF-8 encoding
+    invalid_utf8,
+
+    /// Operation required not implemented functionality
+    not_implemented,
+
+    /// Invalid HTTP method
+    invalid_http_method,
+
+    /// Invalid HTTP version
+    invalid_http_version,
+
+    /// Invalid HTTP status
+    invalid_http_status,
+
+    /// Missing Required Header
+    missing_required_header,
+
+    /// Embedded SHA-1 library error
+    sha1_library,
+
+    /// No support for this feature in this protocol version.
+    no_protocol_support,
+
+    /// Reserved close code used
+    reserved_close_code,
+
+    /// Invalid close code used
+    invalid_close_code,
+
+    /// Using a reason requires a close code
+    reason_requires_code,
+
+    /// Error parsing subprotocols
+    subprotocol_parse_error,
+
+    /// Error parsing extensions
+    extension_parse_error,
+
+    /// Extension related operation was ignored because extensions are disabled
+    extensions_disabled,
+    
+    /// Short Ke3 read. Hybi00 requires a third key to be read from the 8 bytes
+    /// after the handshake. Less than 8 bytes were read.
+    short_key3
+};
+
+/// Category for processor errors
+class processor_category : public lib::error_category {
+public:
+    processor_category() {}
+
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.processor";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case error::general:
+                return "Generic processor error";
+            case error::bad_request:
+                return "invalid user input";
+            case error::protocol_violation:
+                return "Generic protocol violation";
+            case error::message_too_big:
+                return "A message was too large";
+            case error::invalid_payload:
+                return "A payload contained invalid data";
+            case error::invalid_arguments:
+                return "invalid function arguments";
+            case error::invalid_opcode:
+                return "invalid opcode";
+            case error::control_too_big:
+                return "Control messages are limited to fewer than 125 characters";
+            case error::invalid_rsv_bit:
+                return "Invalid use of reserved bits";
+            case error::fragmented_control:
+                return "Control messages cannot be fragmented";
+            case error::invalid_continuation:
+                return "Invalid message continuation";
+            case error::masking_required:
+                return "Clients may not send unmasked frames";
+            case error::masking_forbidden:
+                return "Servers may not send masked frames";
+            case error::non_minimal_encoding:
+                return "Payload length was not minimally encoded";
+            case error::requires_64bit:
+                return "64 bit frames are not supported on 32 bit systems";
+            case error::invalid_utf8:
+                return "Invalid UTF8 encoding";
+            case error::not_implemented:
+                return "Operation required not implemented functionality";
+            case error::invalid_http_method:
+                return "Invalid HTTP method.";
+            case error::invalid_http_version:
+                return "Invalid HTTP version.";
+            case error::invalid_http_status:
+                return "Invalid HTTP status.";
+            case error::missing_required_header:
+                return "A required HTTP header is missing";
+            case error::sha1_library:
+                return "SHA-1 library error";
+            case error::no_protocol_support:
+                return "The WebSocket protocol version in use does not support this feature";
+            case error::reserved_close_code:
+                return "Reserved close code used";
+            case error::invalid_close_code:
+                return "Invalid close code used";
+            case error::reason_requires_code:
+                return "Using a close reason requires a valid close code";
+            case error::subprotocol_parse_error:
+                return "Error parsing subprotocol header";
+            case error::extension_parse_error:
+                return "Error parsing extension header";
+            case error::extensions_disabled:
+                return "Extensions are disabled";
+            case error::short_key3:
+                return "Short Hybi00 Key 3 read";
+            default:
+                return "Unknown";
+        }
+    }
+};
+
+/// Get a reference to a static copy of the processor error category
+inline lib::error_category const & get_processor_category() {
+    static processor_category instance;
+    return instance;
+}
+
+/// Create an error code with the given value and the processor category
+inline lib::error_code make_error_code(error::processor_errors e) {
+    return lib::error_code(static_cast<int>(e), get_processor_category());
+}
+
+/// Converts a processor error_code into a websocket close code
+/**
+ * Looks up the appropriate WebSocket close code that should be sent after an
+ * error of this sort occurred.
+ *
+ * If the error is not in the processor category close::status::blank is
+ * returned.
+ *
+ * If the error isn't normally associated with reasons to close a connection
+ * (such as errors intended to be used internally or delivered to client
+ * applications, ex: invalid arguments) then
+ * close::status::internal_endpoint_error is returned.
+ */
+inline close::status::value to_ws(lib::error_code ec) {
+    if (ec.category() != get_processor_category()) {
+        return close::status::blank;
+    }
+
+    switch (ec.value()) {
+        case error::protocol_violation:
+        case error::control_too_big:
+        case error::invalid_opcode:
+        case error::invalid_rsv_bit:
+        case error::fragmented_control:
+        case error::invalid_continuation:
+        case error::masking_required:
+        case error::masking_forbidden:
+        case error::reserved_close_code:
+        case error::invalid_close_code:
+            return close::status::protocol_error;
+        case error::invalid_payload:
+        case error::invalid_utf8:
+            return close::status::invalid_payload;
+        case error::message_too_big:
+            return close::status::message_too_big;
+        default:
+            return close::status::internal_endpoint_error;
+    }
+}
+
+} // namespace error
+} // namespace processor
+} // namespace websocketpp
+
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum<websocketpp::processor::error::processor_errors>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+
+#endif //WEBSOCKETPP_PROCESSOR_BASE_HPP
diff --git a/subprojects/websocketpp/websocketpp/processors/hybi00.hpp b/subprojects/websocketpp/websocketpp/processors/hybi00.hpp
new file mode 100644
index 000000000..95ad9dfa8
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/processors/hybi00.hpp
@@ -0,0 +1,462 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_PROCESSOR_HYBI00_HPP
+#define WEBSOCKETPP_PROCESSOR_HYBI00_HPP
+
+#include <websocketpp/frame.hpp>
+#include <websocketpp/http/constants.hpp>
+
+#include <websocketpp/utf8_validator.hpp>
+#include <websocketpp/common/network.hpp>
+#include <websocketpp/common/md5.hpp>
+#include <websocketpp/common/platforms.hpp>
+
+#include <websocketpp/processors/processor.hpp>
+
+#include <algorithm>
+#include <cstdlib>
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace processor {
+
+/// Processor for Hybi Draft version 00
+/**
+ * There are many differences between Hybi 00 and Hybi 13
+ */
+template <typename config>
+class hybi00 : public processor<config> {
+public:
+    typedef processor<config> base;
+
+    typedef typename config::request_type request_type;
+    typedef typename config::response_type response_type;
+
+    typedef typename config::message_type message_type;
+    typedef typename message_type::ptr message_ptr;
+
+    typedef typename config::con_msg_manager_type::ptr msg_manager_ptr;
+
+    explicit hybi00(bool secure, bool p_is_server, msg_manager_ptr manager)
+      : processor<config>(secure, p_is_server)
+      , msg_hdr(0x00)
+      , msg_ftr(0xff)
+      , m_state(HEADER)
+      , m_msg_manager(manager) {}
+
+    int get_version() const {
+        return 0;
+    }
+
+    lib::error_code validate_handshake(request_type const & r) const {
+        if (r.get_method() != "GET") {
+            return make_error_code(error::invalid_http_method);
+        }
+
+        if (r.get_version() != "HTTP/1.1") {
+            return make_error_code(error::invalid_http_version);
+        }
+
+        // required headers
+        // Host is required by HTTP/1.1
+        // Connection is required by is_websocket_handshake
+        // Upgrade is required by is_websocket_handshake
+        if (r.get_header("Sec-WebSocket-Key1").empty() ||
+            r.get_header("Sec-WebSocket-Key2").empty() ||
+            r.get_header("Sec-WebSocket-Key3").empty())
+        {
+            return make_error_code(error::missing_required_header);
+        }
+
+        return lib::error_code();
+    }
+
+    lib::error_code process_handshake(request_type const & req,
+        std::string const & subprotocol, response_type & res) const
+    {
+        char key_final[16];
+
+        // copy key1 into final key
+        decode_client_key(req.get_header("Sec-WebSocket-Key1"), &key_final[0]);
+
+        // copy key2 into final key
+        decode_client_key(req.get_header("Sec-WebSocket-Key2"), &key_final[4]);
+
+        // copy key3 into final key
+        // key3 should be exactly 8 bytes. If it is more it will be truncated
+        // if it is less the final key will almost certainly be wrong.
+        // TODO: decide if it is best to silently fail here or produce some sort
+        //       of warning or exception.
+        std::string const & key3 = req.get_header("Sec-WebSocket-Key3");
+        std::copy(key3.c_str(),
+                  key3.c_str()+(std::min)(static_cast<size_t>(8), key3.size()),
+                  &key_final[8]);
+
+        res.append_header(
+            "Sec-WebSocket-Key3",
+            md5::md5_hash_string(std::string(key_final,16))
+        );
+
+        res.append_header("Upgrade","WebSocket");
+        res.append_header("Connection","Upgrade");
+
+        // Echo back client's origin unless our local application set a
+        // more restrictive one.
+        if (res.get_header("Sec-WebSocket-Origin").empty()) {
+            res.append_header("Sec-WebSocket-Origin",req.get_header("Origin"));
+        }
+
+        // Echo back the client's request host unless our local application
+        // set a different one.
+        if (res.get_header("Sec-WebSocket-Location").empty()) {
+            uri_ptr uri = get_uri(req);
+            res.append_header("Sec-WebSocket-Location",uri->str());
+        }
+
+        if (!subprotocol.empty()) {
+            res.replace_header("Sec-WebSocket-Protocol",subprotocol);
+        }
+
+        return lib::error_code();
+    }
+
+    /// Fill in a set of request headers for a client connection request
+    /**
+     * The Hybi 00 processor only implements incoming connections so this will
+     * always return an error.
+     *
+     * @param [out] req  Set of headers to fill in
+     * @param [in] uri The uri being connected to
+     * @param [in] subprotocols The list of subprotocols to request
+     */
+    lib::error_code client_handshake_request(request_type &, uri_ptr,
+        std::vector<std::string> const &) const
+    {
+        return error::make_error_code(error::no_protocol_support);
+    }
+
+    /// Validate the server's response to an outgoing handshake request
+    /**
+     * The Hybi 00 processor only implements incoming connections so this will
+     * always return an error.
+     *
+     * @param req The original request sent
+     * @param res The reponse to generate
+     * @return An error code, 0 on success, non-zero for other errors
+     */
+    lib::error_code validate_server_handshake_response(request_type const &,
+        response_type &) const
+    {
+        return error::make_error_code(error::no_protocol_support);
+    }
+
+    std::string get_raw(response_type const & res) const {
+        response_type temp = res;
+        temp.remove_header("Sec-WebSocket-Key3");
+        return temp.raw() + res.get_header("Sec-WebSocket-Key3");
+    }
+
+    std::string const & get_origin(request_type const & r) const {
+        return r.get_header("Origin");
+    }
+
+    /// Extracts requested subprotocols from a handshake request
+    /**
+     * hybi00 does support subprotocols
+     * https://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-00#section-1.9
+     *
+     * @param [in] req The request to extract from
+     * @param [out] subprotocol_list A reference to a vector of strings to store
+     * the results in.
+     */
+    lib::error_code extract_subprotocols(request_type const & req,
+        std::vector<std::string> & subprotocol_list)
+    {
+        if (!req.get_header("Sec-WebSocket-Protocol").empty()) {
+            http::parameter_list p;
+
+             if (!req.get_header_as_plist("Sec-WebSocket-Protocol",p)) {
+                 http::parameter_list::const_iterator it;
+
+                 for (it = p.begin(); it != p.end(); ++it) {
+                     subprotocol_list.push_back(it->first);
+                 }
+             } else {
+                 return error::make_error_code(error::subprotocol_parse_error);
+             }
+        }
+        return lib::error_code();
+    }
+
+    uri_ptr get_uri(request_type const & request) const {
+        std::string h = request.get_header("Host");
+
+        size_t last_colon = h.rfind(":");
+        size_t last_sbrace = h.rfind("]");
+
+        // no : = hostname with no port
+        // last : before ] = ipv6 literal with no port
+        // : with no ] = hostname with port
+        // : after ] = ipv6 literal with port
+
+        if (last_colon == std::string::npos ||
+            (last_sbrace != std::string::npos && last_sbrace > last_colon))
+        {
+            return lib::make_shared<uri>(base::m_secure, h, request.get_uri());
+        } else {
+            return lib::make_shared<uri>(base::m_secure,
+                                   h.substr(0,last_colon),
+                                   h.substr(last_colon+1),
+                                   request.get_uri());
+        }
+
+        // TODO: check if get_uri is a full uri
+    }
+
+    /// Get hybi00 handshake key3
+    /**
+     * @todo This doesn't appear to be used anymore. It might be able to be
+     * removed
+     */
+    std::string get_key3() const {
+        return "";
+    }
+
+    /// Process new websocket connection bytes
+    size_t consume(uint8_t * buf, size_t len, lib::error_code & ec) {
+        // if in state header we are expecting a 0x00 byte, if we don't get one
+        // it is a fatal error
+        size_t p = 0; // bytes processed
+        size_t l = 0;
+
+        ec = lib::error_code();
+
+        while (p < len) {
+            if (m_state == HEADER) {
+                if (buf[p] == msg_hdr) {
+                    p++;
+                    m_msg_ptr = m_msg_manager->get_message(frame::opcode::text,1);
+
+                    if (!m_msg_ptr) {
+                        ec = make_error_code(websocketpp::error::no_incoming_buffers);
+                        m_state = FATAL_ERROR;
+                    } else {
+                        m_state = PAYLOAD;
+                    }
+                } else {
+                    ec = make_error_code(error::protocol_violation);
+                    m_state = FATAL_ERROR;
+                }
+            } else if (m_state == PAYLOAD) {
+                uint8_t *it = std::find(buf+p,buf+len,msg_ftr);
+
+                // 0    1    2    3    4    5
+                // 0x00 0x23 0x23 0x23 0xff 0xXX
+
+                // Copy payload bytes into message
+                l = static_cast<size_t>(it-(buf+p));
+                m_msg_ptr->append_payload(buf+p,l);
+                p += l;
+
+                if (it != buf+len) {
+                    // message is done, copy it and the trailing
+                    p++;
+                    // TODO: validation
+                    m_state = READY;
+                }
+            } else {
+                // TODO
+                break;
+            }
+        }
+        // If we get one, we create a new message and move to application state
+
+        // if in state application we are copying bytes into the output message
+        // and validating them for UTF8 until we hit a 0xff byte. Once we hit
+        // 0x00, the message is complete and is dispatched. Then we go back to
+        // header state.
+
+        //ec = make_error_code(error::not_implemented);
+        return p;
+    }
+
+    bool ready() const {
+        return (m_state == READY);
+    }
+
+    bool get_error() const {
+        return false;
+    }
+
+    message_ptr get_message() {
+        message_ptr ret = m_msg_ptr;
+        m_msg_ptr = message_ptr();
+        m_state = HEADER;
+        return ret;
+    }
+
+    /// Prepare a message for writing
+    /**
+     * Performs validation, masking, compression, etc. will return an error if
+     * there was an error, otherwise msg will be ready to be written
+     */
+    virtual lib::error_code prepare_data_frame(message_ptr in, message_ptr out)
+    {
+        if (!in || !out) {
+            return make_error_code(error::invalid_arguments);
+        }
+
+        // TODO: check if the message is prepared already
+
+        // validate opcode
+        if (in->get_opcode() != frame::opcode::text) {
+            return make_error_code(error::invalid_opcode);
+        }
+
+        std::string& i = in->get_raw_payload();
+        //std::string& o = out->get_raw_payload();
+
+        // validate payload utf8
+        if (!utf8_validator::validate(i)) {
+            return make_error_code(error::invalid_payload);
+        }
+
+        // generate header
+        out->set_header(std::string(reinterpret_cast<char const *>(&msg_hdr),1));
+
+        // process payload
+        out->set_payload(i);
+        out->append_payload(std::string(reinterpret_cast<char const *>(&msg_ftr),1));
+
+        // hybi00 doesn't support compression
+        // hybi00 doesn't have masking
+
+        out->set_prepared(true);
+
+        return lib::error_code();
+    }
+
+    /// Prepare a ping frame
+    /**
+     * Hybi 00 doesn't support pings so this will always return an error
+     *
+     * @param in The string to use for the ping payload
+     * @param out The message buffer to prepare the ping in.
+     * @return Status code, zero on success, non-zero on failure
+     */
+    lib::error_code prepare_ping(std::string const &, message_ptr) const
+    {
+        return lib::error_code(error::no_protocol_support);
+    }
+
+    /// Prepare a pong frame
+    /**
+     * Hybi 00 doesn't support pongs so this will always return an error
+     *
+     * @param in The string to use for the pong payload
+     * @param out The message buffer to prepare the pong in.
+     * @return Status code, zero on success, non-zero on failure
+     */
+    lib::error_code prepare_pong(std::string const &, message_ptr) const
+    {
+        return lib::error_code(error::no_protocol_support);
+    }
+
+    /// Prepare a close frame
+    /**
+     * Hybi 00 doesn't support the close code or reason so these parameters are
+     * ignored.
+     *
+     * @param code The close code to send
+     * @param reason The reason string to send
+     * @param out The message buffer to prepare the fame in
+     * @return Status code, zero on success, non-zero on failure
+     */
+    lib::error_code prepare_close(close::status::value, std::string const &, 
+        message_ptr out) const
+    {
+        if (!out) {
+            return lib::error_code(error::invalid_arguments);
+        }
+
+        std::string val;
+        val.append(1,'\xff');
+        val.append(1,'\x00');
+        out->set_payload(val);
+        out->set_prepared(true);
+
+        return lib::error_code();
+    }
+private:
+    void decode_client_key(std::string const & key, char * result) const {
+        unsigned int spaces = 0;
+        std::string digits;
+        uint32_t num;
+
+        // key2
+        for (size_t i = 0; i < key.size(); i++) {
+            if (key[i] == ' ') {
+                spaces++;
+            } else if (key[i] >= '0' && key[i] <= '9') {
+                digits += key[i];
+            }
+        }
+
+        num = static_cast<uint32_t>(strtoul(digits.c_str(), NULL, 10));
+        if (spaces > 0 && num > 0) {
+            num = htonl(num/spaces);
+            std::copy(reinterpret_cast<char*>(&num),
+                      reinterpret_cast<char*>(&num)+4,
+                      result);
+        } else {
+            std::fill(result,result+4,0);
+        }
+    }
+
+    enum state {
+        HEADER = 0,
+        PAYLOAD = 1,
+        READY = 2,
+        FATAL_ERROR = 3
+    };
+
+    uint8_t const msg_hdr;
+    uint8_t const msg_ftr;
+
+    state m_state;
+
+    msg_manager_ptr m_msg_manager;
+    message_ptr m_msg_ptr;
+    utf8_validator::validator m_validator;
+};
+
+} // namespace processor
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_PROCESSOR_HYBI00_HPP
diff --git a/subprojects/websocketpp/websocketpp/processors/hybi07.hpp b/subprojects/websocketpp/websocketpp/processors/hybi07.hpp
new file mode 100644
index 000000000..14b67c21a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/processors/hybi07.hpp
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_PROCESSOR_HYBI07_HPP
+#define WEBSOCKETPP_PROCESSOR_HYBI07_HPP
+
+#include <websocketpp/processors/hybi08.hpp>
+
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace processor {
+
+/// Processor for Hybi Draft version 07
+/**
+ * The primary difference between 07 and 08 is a version number.
+ */
+template <typename config>
+class hybi07 : public hybi08<config> {
+public:
+    typedef typename config::request_type request_type;
+
+    typedef typename config::con_msg_manager_type::ptr msg_manager_ptr;
+    typedef typename config::rng_type rng_type;
+
+    explicit hybi07(bool secure, bool p_is_server, msg_manager_ptr manager, rng_type& rng)
+      : hybi08<config>(secure, p_is_server, manager, rng) {}
+
+    /// Fill in a set of request headers for a client connection request
+    /**
+     * The Hybi 07 processor only implements incoming connections so this will
+     * always return an error.
+     *
+     * @param [out] req  Set of headers to fill in
+     * @param [in] uri The uri being connected to
+     * @param [in] subprotocols The list of subprotocols to request
+     */
+    lib::error_code client_handshake_request(request_type &, uri_ptr,
+        std::vector<std::string> const &) const
+    {
+        return error::make_error_code(error::no_protocol_support);
+    }
+
+    int get_version() const {
+        return 7;
+    }
+private:
+};
+
+} // namespace processor
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_PROCESSOR_HYBI07_HPP
diff --git a/subprojects/websocketpp/websocketpp/processors/hybi08.hpp b/subprojects/websocketpp/websocketpp/processors/hybi08.hpp
new file mode 100644
index 000000000..15f6e6586
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/processors/hybi08.hpp
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_PROCESSOR_HYBI08_HPP
+#define WEBSOCKETPP_PROCESSOR_HYBI08_HPP
+
+#include <websocketpp/processors/hybi13.hpp>
+
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace processor {
+
+/// Processor for Hybi Draft version 08
+/**
+ * The primary difference between 08 and 13 is a different origin header name
+ */
+template <typename config>
+class hybi08 : public hybi13<config> {
+public:
+    typedef hybi08<config> type;
+    typedef typename config::request_type request_type;
+
+    typedef typename config::con_msg_manager_type::ptr msg_manager_ptr;
+    typedef typename config::rng_type rng_type;
+
+    explicit hybi08(bool secure, bool p_is_server, msg_manager_ptr manager, rng_type& rng)
+      : hybi13<config>(secure, p_is_server, manager, rng) {}
+
+    /// Fill in a set of request headers for a client connection request
+    /**
+     * The Hybi 08 processor only implements incoming connections so this will
+     * always return an error.
+     *
+     * @param [out] req  Set of headers to fill in
+     * @param [in] uri The uri being connected to
+     * @param [in] subprotocols The list of subprotocols to request
+     */
+    lib::error_code client_handshake_request(request_type &, uri_ptr,
+        std::vector<std::string> const &) const
+    {
+        return error::make_error_code(error::no_protocol_support);
+    }
+
+    int get_version() const {
+        return 8;
+    }
+
+    std::string const & get_origin(request_type const & r) const {
+        return r.get_header("Sec-WebSocket-Origin");
+    }
+private:
+};
+
+} // namespace processor
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_PROCESSOR_HYBI08_HPP
diff --git a/subprojects/websocketpp/websocketpp/processors/hybi13.hpp b/subprojects/websocketpp/websocketpp/processors/hybi13.hpp
new file mode 100644
index 000000000..ca1243926
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/processors/hybi13.hpp
@@ -0,0 +1,1078 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_PROCESSOR_HYBI13_HPP
+#define WEBSOCKETPP_PROCESSOR_HYBI13_HPP
+
+#include <websocketpp/processors/processor.hpp>
+
+#include <websocketpp/frame.hpp>
+#include <websocketpp/http/constants.hpp>
+
+#include <websocketpp/utf8_validator.hpp>
+#include <websocketpp/sha1/sha1.hpp>
+#include <websocketpp/base64/base64.hpp>
+
+#include <websocketpp/common/network.hpp>
+#include <websocketpp/common/platforms.hpp>
+
+#include <algorithm>
+#include <cassert>
+#include <string>
+#include <vector>
+#include <utility>
+
+namespace websocketpp {
+namespace processor {
+
+/// Processor for Hybi version 13 (RFC6455)
+template <typename config>
+class hybi13 : public processor<config> {
+public:
+    typedef processor<config> base;
+
+    typedef typename config::request_type request_type;
+    typedef typename config::response_type response_type;
+
+    typedef typename config::message_type message_type;
+    typedef typename message_type::ptr message_ptr;
+
+    typedef typename config::con_msg_manager_type msg_manager_type;
+    typedef typename msg_manager_type::ptr msg_manager_ptr;
+    typedef typename config::rng_type rng_type;
+
+    typedef typename config::permessage_deflate_type permessage_deflate_type;
+
+    typedef std::pair<lib::error_code,std::string> err_str_pair;
+
+    explicit hybi13(bool secure, bool p_is_server, msg_manager_ptr manager, rng_type& rng)
+      : processor<config>(secure, p_is_server)
+      , m_msg_manager(manager)
+      , m_rng(rng)
+    {
+        reset_headers();
+    }
+
+    int get_version() const {
+        return 13;
+    }
+
+    bool has_permessage_deflate() const {
+        return m_permessage_deflate.is_implemented();
+    }
+
+    err_str_pair negotiate_extensions(request_type const & request) {
+        return negotiate_extensions_helper(request);
+    }
+    
+    err_str_pair negotiate_extensions(response_type const & response) {
+        return negotiate_extensions_helper(response);
+    }
+    
+    /// Extension negotiation helper function
+    /**
+     * This exists mostly because the code for requests and responses is
+     * identical and I can't have virtual template methods.
+     */
+    template <typename header_type>
+    err_str_pair negotiate_extensions_helper(header_type const & header) {
+        err_str_pair ret;
+
+        // Respect blanket disabling of all extensions and don't even parse
+        // the extension header
+        if (!config::enable_extensions) {
+            ret.first = make_error_code(error::extensions_disabled);
+            return ret;
+        }
+
+        http::parameter_list p;
+
+        bool error = header.get_header_as_plist("Sec-WebSocket-Extensions",p);
+
+        if (error) {
+            ret.first = make_error_code(error::extension_parse_error);
+            return ret;
+        }
+
+        // If there are no extensions parsed then we are done!
+        if (p.size() == 0) {
+            return ret;
+        }
+
+        http::parameter_list::const_iterator it;
+
+        // look through the list of extension requests to find the first
+        // one that we can accept.
+        if (m_permessage_deflate.is_implemented()) {
+            err_str_pair neg_ret;
+            for (it = p.begin(); it != p.end(); ++it) {
+                // not a permessage-deflate extension request, ignore
+                if (it->first != "permessage-deflate") {
+                    continue;
+                }
+
+                // if we have already successfully negotiated this extension
+                // then skip any other requests to negotiate the same one
+                // with different parameters 
+                if (m_permessage_deflate.is_enabled()) {
+                    continue;
+                }
+                
+                // attempt to negotiate this offer
+                neg_ret = m_permessage_deflate.negotiate(it->second);
+
+                if (neg_ret.first) {
+                    // negotiation offer failed. Do nothing. We will continue
+                    // searching for a permessage-deflate config that succeeds
+                    continue;
+                }
+
+                // Negotiation tentatively succeeded
+
+                // Actually try to initialize the extension before we
+                // deem negotiation complete
+                lib::error_code ec = m_permessage_deflate.init(base::m_server);
+
+                if (ec) {
+                    // Negotiation succeeded but initialization failed this is 
+                    // an error that should stop negotiation of permessage 
+                    // deflate. Return the reason for the init failure
+
+                    ret.first = ec;
+                    break;
+                } else {
+                    // Successfully initialized, push the negotiated response into
+                    // the reply and stop looking for additional permessage-deflate
+                    // extensions
+                    ret.second += neg_ret.second;
+                    break;
+                }
+            }
+        }
+
+        // support for future extensions would go here. Should check the value of 
+        // ret.first before continuing. Might need to consider whether failure of
+        // negotiation of an earlier extension should stop negotiation of subsequent
+        // ones
+
+        return ret;
+    }
+
+    lib::error_code validate_handshake(request_type const & r) const {
+        if (r.get_method() != "GET") {
+            return make_error_code(error::invalid_http_method);
+        }
+
+        if (r.get_version() != "HTTP/1.1") {
+            return make_error_code(error::invalid_http_version);
+        }
+
+        // required headers
+        // Host is required by HTTP/1.1
+        // Connection is required by is_websocket_handshake
+        // Upgrade is required by is_websocket_handshake
+        if (r.get_header("Sec-WebSocket-Key").empty()) {
+            return make_error_code(error::missing_required_header);
+        }
+
+        return lib::error_code();
+    }
+
+    /* TODO: the 'subprotocol' parameter may need to be expanded into a more
+     * generic struct if other user input parameters to the processed handshake
+     * are found.
+     */
+    lib::error_code process_handshake(request_type const & request, 
+        std::string const & subprotocol, response_type & response) const
+    {
+        std::string server_key = request.get_header("Sec-WebSocket-Key");
+
+        lib::error_code ec = process_handshake_key(server_key);
+
+        if (ec) {
+            return ec;
+        }
+
+        response.replace_header("Sec-WebSocket-Accept",server_key);
+        response.append_header("Upgrade",constants::upgrade_token);
+        response.append_header("Connection",constants::connection_token);
+
+        if (!subprotocol.empty()) {
+            response.replace_header("Sec-WebSocket-Protocol",subprotocol);
+        }
+
+        return lib::error_code();
+    }
+
+    /// Fill in a set of request headers for a client connection request
+    /**
+     * @param [out] req  Set of headers to fill in
+     * @param [in] uri The uri being connected to
+     * @param [in] subprotocols The list of subprotocols to request
+     */
+    lib::error_code client_handshake_request(request_type & req, uri_ptr
+        uri, std::vector<std::string> const & subprotocols) const
+    {
+        req.set_method("GET");
+        req.set_uri(uri->get_resource());
+        req.set_version("HTTP/1.1");
+
+        req.append_header("Upgrade","websocket");
+        req.append_header("Connection","Upgrade");
+        req.replace_header("Sec-WebSocket-Version","13");
+        req.replace_header("Host",uri->get_host_port());
+
+        if (!subprotocols.empty()) {
+            std::ostringstream result;
+            std::vector<std::string>::const_iterator it = subprotocols.begin();
+            result << *it++;
+            while (it != subprotocols.end()) {
+                result << ", " << *it++;
+            }
+
+            req.replace_header("Sec-WebSocket-Protocol",result.str());
+        }
+
+        // Generate handshake key
+        frame::uint32_converter conv;
+        unsigned char raw_key[16];
+
+        for (int i = 0; i < 4; i++) {
+            conv.i = m_rng();
+            std::copy(conv.c,conv.c+4,&raw_key[i*4]);
+        }
+
+        req.replace_header("Sec-WebSocket-Key",base64_encode(raw_key, 16));
+
+        if (m_permessage_deflate.is_implemented()) {
+            std::string offer = m_permessage_deflate.generate_offer();
+            if (!offer.empty()) {
+                req.replace_header("Sec-WebSocket-Extensions",offer);
+            }
+        }
+
+        return lib::error_code();
+    }
+
+    /// Validate the server's response to an outgoing handshake request
+    /**
+     * @param req The original request sent
+     * @param res The reponse to generate
+     * @return An error code, 0 on success, non-zero for other errors
+     */
+    lib::error_code validate_server_handshake_response(request_type const & req,
+        response_type& res) const
+    {
+        // A valid response has an HTTP 101 switching protocols code
+        if (res.get_status_code() != http::status_code::switching_protocols) {
+            return error::make_error_code(error::invalid_http_status);
+        }
+
+        // And the upgrade token in an upgrade header
+        std::string const & upgrade_header = res.get_header("Upgrade");
+        if (utility::ci_find_substr(upgrade_header, constants::upgrade_token,
+            sizeof(constants::upgrade_token)-1) == upgrade_header.end())
+        {
+            return error::make_error_code(error::missing_required_header);
+        }
+
+        // And the websocket token in the connection header
+        std::string const & con_header = res.get_header("Connection");
+        if (utility::ci_find_substr(con_header, constants::connection_token,
+            sizeof(constants::connection_token)-1) == con_header.end())
+        {
+            return error::make_error_code(error::missing_required_header);
+        }
+
+        // And has a valid Sec-WebSocket-Accept value
+        std::string key = req.get_header("Sec-WebSocket-Key");
+        lib::error_code ec = process_handshake_key(key);
+
+        if (ec || key != res.get_header("Sec-WebSocket-Accept")) {
+            return error::make_error_code(error::missing_required_header);
+        }
+
+        // check extensions
+
+        return lib::error_code();
+    }
+
+    std::string get_raw(response_type const & res) const {
+        return res.raw();
+    }
+
+    std::string const & get_origin(request_type const & r) const {
+        return r.get_header("Origin");
+    }
+
+    lib::error_code extract_subprotocols(request_type const & req,
+        std::vector<std::string> & subprotocol_list)
+    {
+        if (!req.get_header("Sec-WebSocket-Protocol").empty()) {
+            http::parameter_list p;
+
+             if (!req.get_header_as_plist("Sec-WebSocket-Protocol",p)) {
+                 http::parameter_list::const_iterator it;
+
+                 for (it = p.begin(); it != p.end(); ++it) {
+                     subprotocol_list.push_back(it->first);
+                 }
+             } else {
+                 return error::make_error_code(error::subprotocol_parse_error);
+             }
+        }
+        return lib::error_code();
+    }
+
+    uri_ptr get_uri(request_type const & request) const {
+        return get_uri_from_host(request,(base::m_secure ? "wss" : "ws"));
+    }
+
+    /// Process new websocket connection bytes
+    /**
+     *
+     * Hybi 13 data streams represent a series of variable length frames. Each
+     * frame is made up of a series of fixed length fields. The lengths of later
+     * fields are contained in earlier fields. The first field length is fixed
+     * by the spec.
+     *
+     * This processor represents a state machine that keeps track of what field
+     * is presently being read and how many more bytes are needed to complete it
+     *
+     *
+     *
+     *
+     * Read two header bytes
+     *   Extract full frame length.
+     *   Read extra header bytes
+     * Validate frame header (including extension validate)
+     * Read extension data into extension message state object
+     * Read payload data into payload
+     *
+     * @param buf Input buffer
+     *
+     * @param len Length of input buffer
+     *
+     * @return Number of bytes processed or zero on error
+     */
+    size_t consume(uint8_t * buf, size_t len, lib::error_code & ec) {
+        size_t p = 0;
+
+        ec = lib::error_code();
+
+        //std::cout << "consume: " << utility::to_hex(buf,len) << std::endl;
+
+        // Loop while we don't have a message ready and we still have bytes
+        // left to process.
+        while (m_state != READY && m_state != FATAL_ERROR &&
+               (p < len || m_bytes_needed == 0))
+        {
+            if (m_state == HEADER_BASIC) {
+                p += this->copy_basic_header_bytes(buf+p,len-p);
+
+                if (m_bytes_needed > 0) {
+                    continue;
+                }
+
+                ec = this->validate_incoming_basic_header(
+                    m_basic_header, base::m_server, !m_data_msg.msg_ptr
+                );
+                if (ec) {break;}
+
+                // extract full header size and adjust consume state accordingly
+                m_state = HEADER_EXTENDED;
+                m_cursor = 0;
+                m_bytes_needed = frame::get_header_len(m_basic_header) -
+                    frame::BASIC_HEADER_LENGTH;
+            } else if (m_state == HEADER_EXTENDED) {
+                p += this->copy_extended_header_bytes(buf+p,len-p);
+
+                if (m_bytes_needed > 0) {
+                    continue;
+                }
+
+                ec = validate_incoming_extended_header(m_basic_header,m_extended_header);
+                if (ec){break;}
+
+                m_state = APPLICATION;
+                m_bytes_needed = static_cast<size_t>(get_payload_size(m_basic_header,m_extended_header));
+
+                // check if this frame is the start of a new message and set up
+                // the appropriate message metadata.
+                frame::opcode::value op = frame::get_opcode(m_basic_header);
+
+                // TODO: get_message failure conditions
+
+                if (frame::opcode::is_control(op)) {
+                    m_control_msg = msg_metadata(
+                        m_msg_manager->get_message(op,m_bytes_needed),
+                        frame::get_masking_key(m_basic_header,m_extended_header)
+                    );
+
+                    m_current_msg = &m_control_msg;
+                } else {
+                    if (!m_data_msg.msg_ptr) {
+                        if (m_bytes_needed > base::m_max_message_size) {
+                            ec = make_error_code(error::message_too_big);
+                            break;
+                        }
+                        
+                        m_data_msg = msg_metadata(
+                            m_msg_manager->get_message(op,m_bytes_needed),
+                            frame::get_masking_key(m_basic_header,m_extended_header)
+                        );
+                        
+                        if (m_permessage_deflate.is_enabled()) {
+                            m_data_msg.msg_ptr->set_compressed(frame::get_rsv1(m_basic_header));
+                        }
+                    } else {
+                        // Fetch the underlying payload buffer from the data message we
+                        // are writing into.
+                        std::string & out = m_data_msg.msg_ptr->get_raw_payload();
+                        
+                        if (out.size() + m_bytes_needed > base::m_max_message_size) {
+                            ec = make_error_code(error::message_too_big);
+                            break;
+                        }
+                        
+                        // Each frame starts a new masking key. All other state
+                        // remains between frames.
+                        m_data_msg.prepared_key = prepare_masking_key(
+                            frame::get_masking_key(
+                                m_basic_header,
+                                m_extended_header
+                            )
+                        );
+                        
+                        out.reserve(out.size() + m_bytes_needed);
+                    }
+                    m_current_msg = &m_data_msg;
+                }
+            } else if (m_state == EXTENSION) {
+                m_state = APPLICATION;
+            } else if (m_state == APPLICATION) {
+                size_t bytes_to_process = (std::min)(m_bytes_needed,len-p);
+
+                if (bytes_to_process > 0) {
+                    p += this->process_payload_bytes(buf+p,bytes_to_process,ec);
+
+                    if (ec) {break;}
+                }
+
+                if (m_bytes_needed > 0) {
+                    continue;
+                }
+
+                // If this was the last frame in the message set the ready flag.
+                // Otherwise, reset processor state to read additional frames.
+                if (frame::get_fin(m_basic_header)) {
+                    ec = finalize_message();
+                    if (ec) {
+                        break;
+                    }
+                } else {
+                    this->reset_headers();
+                }
+            } else {
+                // shouldn't be here
+                ec = make_error_code(error::general);
+                return 0;
+            }
+        }
+
+        return p;
+    }
+
+    /// Perform any finalization actions on an incoming message
+    /**
+     * Called after the full message is received. Provides the opportunity for
+     * extensions to complete any data post processing as well as final UTF8
+     * validation checks for text messages.
+     *
+     * @return A code indicating errors, if any
+     */
+    lib::error_code finalize_message() {
+        std::string & out = m_current_msg->msg_ptr->get_raw_payload();
+
+        // if the frame is compressed, append the compression
+        // trailer and flush the compression buffer.
+        if (m_permessage_deflate.is_enabled()
+            && m_current_msg->msg_ptr->get_compressed())
+        {
+            uint8_t trailer[4] = {0x00, 0x00, 0xff, 0xff};
+
+            // Decompress current buffer into the message buffer
+            lib::error_code ec;
+            ec = m_permessage_deflate.decompress(trailer,4,out);
+            if (ec) {
+                return ec;
+            }
+        }
+
+        // ensure that text messages end on a valid UTF8 code point
+        if (frame::get_opcode(m_basic_header) == frame::opcode::TEXT) {
+            if (!m_current_msg->validator.complete()) {
+                return make_error_code(error::invalid_utf8);
+            }
+        }
+
+        m_state = READY;
+
+        return lib::error_code();
+    }
+
+    void reset_headers() {
+        m_state = HEADER_BASIC;
+        m_bytes_needed = frame::BASIC_HEADER_LENGTH;
+
+        m_basic_header.b0 = 0x00;
+        m_basic_header.b1 = 0x00;
+
+        std::fill_n(
+            m_extended_header.bytes,
+            frame::MAX_EXTENDED_HEADER_LENGTH,
+            0x00
+        );
+    }
+
+    /// Test whether or not the processor has a message ready
+    bool ready() const {
+        return (m_state == READY);
+    }
+
+    message_ptr get_message() {
+        if (!ready()) {
+            return message_ptr();
+        }
+        message_ptr ret = m_current_msg->msg_ptr;
+        m_current_msg->msg_ptr.reset();
+
+        if (frame::opcode::is_control(ret->get_opcode())) {
+            m_control_msg.msg_ptr.reset();
+        } else {
+            m_data_msg.msg_ptr.reset();
+        }
+
+        this->reset_headers();
+
+        return ret;
+    }
+
+    /// Test whether or not the processor is in a fatal error state.
+    bool get_error() const {
+        return m_state == FATAL_ERROR;
+    }
+
+    size_t get_bytes_needed() const {
+        return m_bytes_needed;
+    }
+
+    /// Prepare a user data message for writing
+    /**
+     * Performs validation, masking, compression, etc. will return an error if
+     * there was an error, otherwise msg will be ready to be written
+     *
+     * TODO: tests
+     *
+     * @param in An unprepared message to prepare
+     * @param out A message to be overwritten with the prepared message
+     * @return error code
+     */
+    virtual lib::error_code prepare_data_frame(message_ptr in, message_ptr out)
+    {
+        if (!in || !out) {
+            return make_error_code(error::invalid_arguments);
+        }
+
+        frame::opcode::value op = in->get_opcode();
+
+        // validate opcode: only regular data frames
+        if (frame::opcode::is_control(op)) {
+            return make_error_code(error::invalid_opcode);
+        }
+
+        std::string& i = in->get_raw_payload();
+        std::string& o = out->get_raw_payload();
+
+        // validate payload utf8
+        if (op == frame::opcode::TEXT && !utf8_validator::validate(i)) {
+            return make_error_code(error::invalid_payload);
+        }
+
+        frame::masking_key_type key;
+        bool masked = !base::m_server;
+        bool compressed = m_permessage_deflate.is_enabled()
+                          && in->get_compressed();
+        bool fin = in->get_fin();
+
+        if (masked) {
+            // Generate masking key.
+            key.i = m_rng();
+        } else {
+            key.i = 0;
+        }
+
+        // prepare payload
+        if (compressed) {
+            // compress and store in o after header.
+            m_permessage_deflate.compress(i,o);
+
+            if (o.size() < 4) {
+                return make_error_code(error::general);
+            }
+
+            // Strip trailing 4 0x00 0x00 0xff 0xff bytes before writing to the
+            // wire
+            o.resize(o.size()-4);
+
+            // mask in place if necessary
+            if (masked) {
+                this->masked_copy(o,o,key);
+            }
+        } else {
+            // no compression, just copy data into the output buffer
+            o.resize(i.size());
+
+            // if we are masked, have the masking function write to the output
+            // buffer directly to avoid another copy. If not masked, copy
+            // directly without masking.
+            if (masked) {
+                this->masked_copy(i,o,key);
+            } else {
+                std::copy(i.begin(),i.end(),o.begin());
+            }
+        }
+
+        // generate header
+        frame::basic_header h(op,o.size(),fin,masked,compressed);
+
+        if (masked) {
+            frame::extended_header e(o.size(),key.i);
+            out->set_header(frame::prepare_header(h,e));
+        } else {
+            frame::extended_header e(o.size());
+            out->set_header(frame::prepare_header(h,e));
+        }
+
+        out->set_prepared(true);
+        out->set_opcode(op);
+
+        return lib::error_code();
+    }
+
+    /// Get URI
+    lib::error_code prepare_ping(std::string const & in, message_ptr out) const {
+        return this->prepare_control(frame::opcode::PING,in,out);
+    }
+
+    lib::error_code prepare_pong(std::string const & in, message_ptr out) const {
+        return this->prepare_control(frame::opcode::PONG,in,out);
+    }
+
+    virtual lib::error_code prepare_close(close::status::value code,
+        std::string const & reason, message_ptr out) const
+    {
+        if (close::status::reserved(code)) {
+            return make_error_code(error::reserved_close_code);
+        }
+
+        if (close::status::invalid(code) && code != close::status::no_status) {
+            return make_error_code(error::invalid_close_code);
+        }
+
+        if (code == close::status::no_status && reason.size() > 0) {
+            return make_error_code(error::reason_requires_code);
+        }
+
+        if (reason.size() > frame:: limits::payload_size_basic-2) {
+            return make_error_code(error::control_too_big);
+        }
+
+        std::string payload;
+
+        if (code != close::status::no_status) {
+            close::code_converter val;
+            val.i = htons(code);
+
+            payload.resize(reason.size()+2);
+
+            payload[0] = val.c[0];
+            payload[1] = val.c[1];
+
+            std::copy(reason.begin(),reason.end(),payload.begin()+2);
+        }
+
+        return this->prepare_control(frame::opcode::CLOSE,payload,out);
+    }
+protected:
+    /// Convert a client handshake key into a server response key in place
+    lib::error_code process_handshake_key(std::string & key) const {
+        key.append(constants::handshake_guid);
+
+        unsigned char message_digest[20];
+        sha1::calc(key.c_str(),key.length(),message_digest);
+        key = base64_encode(message_digest,20);
+
+        return lib::error_code();
+    }
+
+    /// Reads bytes from buf into m_basic_header
+    size_t copy_basic_header_bytes(uint8_t const * buf, size_t len) {
+        if (len == 0 || m_bytes_needed == 0) {
+            return 0;
+        }
+
+        if (len > 1) {
+            // have at least two bytes
+            if (m_bytes_needed == 2) {
+                m_basic_header.b0 = buf[0];
+                m_basic_header.b1 = buf[1];
+                m_bytes_needed -= 2;
+                return 2;
+            } else {
+                m_basic_header.b1 = buf[0];
+                m_bytes_needed--;
+                return 1;
+            }
+        } else {
+            // have exactly one byte
+            if (m_bytes_needed == 2) {
+                m_basic_header.b0 = buf[0];
+                m_bytes_needed--;
+                return 1;
+            } else {
+                m_basic_header.b1 = buf[0];
+                m_bytes_needed--;
+                return 1;
+            }
+        }
+    }
+
+    /// Reads bytes from buf into m_extended_header
+    size_t copy_extended_header_bytes(uint8_t const * buf, size_t len) {
+        size_t bytes_to_read = (std::min)(m_bytes_needed,len);
+
+        std::copy(buf,buf+bytes_to_read,m_extended_header.bytes+m_cursor);
+        m_cursor += bytes_to_read;
+        m_bytes_needed -= bytes_to_read;
+
+        return bytes_to_read;
+    }
+
+    /// Reads bytes from buf into message payload
+    /**
+     * This function performs unmasking and uncompression, validates the
+     * decoded bytes, and writes them to the appropriate message buffer.
+     *
+     * This member function will use the input buffer as stratch space for its
+     * work. The raw input bytes will not be preserved. This applies only to the
+     * bytes actually needed. At most min(m_bytes_needed,len) will be processed.
+     *
+     * @param buf Input/working buffer
+     * @param len Length of buf
+     * @return Number of bytes processed or zero in case of an error
+     */
+    size_t process_payload_bytes(uint8_t * buf, size_t len, lib::error_code& ec)
+    {
+        // unmask if masked
+        if (frame::get_masked(m_basic_header)) {
+            m_current_msg->prepared_key = frame::byte_mask_circ(
+                buf, len, m_current_msg->prepared_key);
+            // TODO: SIMD masking
+        }
+
+        std::string & out = m_current_msg->msg_ptr->get_raw_payload();
+        size_t offset = out.size();
+
+        // decompress message if needed.
+        if (m_permessage_deflate.is_enabled()
+            && m_current_msg->msg_ptr->get_compressed())
+        {
+            // Decompress current buffer into the message buffer
+            ec = m_permessage_deflate.decompress(buf,len,out);
+            if (ec) {
+                return 0;
+            }
+        } else {
+            // No compression, straight copy
+            out.append(reinterpret_cast<char *>(buf),len);
+        }
+
+        // validate unmasked, decompressed values
+        if (m_current_msg->msg_ptr->get_opcode() == frame::opcode::TEXT) {
+            if (!m_current_msg->validator.decode(out.begin()+offset,out.end())) {
+                ec = make_error_code(error::invalid_utf8);
+                return 0;
+            }
+        }
+
+        m_bytes_needed -= len;
+
+        return len;
+    }
+
+    /// Validate an incoming basic header
+    /**
+     * Validates an incoming hybi13 basic header.
+     *
+     * @param h The basic header to validate
+     * @param is_server Whether or not the endpoint that received this frame
+     * is a server.
+     * @param new_msg Whether or not this is the first frame of the message
+     * @return 0 on success or a non-zero error code on failure
+     */
+    lib::error_code validate_incoming_basic_header(frame::basic_header const & h,
+        bool is_server, bool new_msg) const
+    {
+        frame::opcode::value op = frame::get_opcode(h);
+
+        // Check control frame size limit
+        if (frame::opcode::is_control(op) &&
+            frame::get_basic_size(h) > frame::limits::payload_size_basic)
+        {
+            return make_error_code(error::control_too_big);
+        }
+
+        // Check that RSV bits are clear
+        // The only RSV bits allowed are rsv1 if the permessage_compress
+        // extension is enabled for this connection and the message is not
+        // a control message.
+        //
+        // TODO: unit tests for this
+        if (frame::get_rsv1(h) && (!m_permessage_deflate.is_enabled()
+                || frame::opcode::is_control(op)))
+        {
+            return make_error_code(error::invalid_rsv_bit);
+        }
+
+        if (frame::get_rsv2(h) || frame::get_rsv3(h)) {
+            return make_error_code(error::invalid_rsv_bit);
+        }
+
+        // Check for reserved opcodes
+        if (frame::opcode::reserved(op)) {
+            return make_error_code(error::invalid_opcode);
+        }
+
+        // Check for invalid opcodes
+        // TODO: unit tests for this?
+        if (frame::opcode::invalid(op)) {
+            return make_error_code(error::invalid_opcode);
+        }
+
+        // Check for fragmented control message
+        if (frame::opcode::is_control(op) && !frame::get_fin(h)) {
+            return make_error_code(error::fragmented_control);
+        }
+
+        // Check for continuation without an active message
+        if (new_msg && op == frame::opcode::CONTINUATION) {
+            return make_error_code(error::invalid_continuation);
+        }
+
+        // Check for new data frame when expecting continuation
+        if (!new_msg && !frame::opcode::is_control(op) &&
+            op != frame::opcode::CONTINUATION)
+        {
+            return make_error_code(error::invalid_continuation);
+        }
+
+        // Servers should reject any unmasked frames from clients.
+        // Clients should reject any masked frames from servers.
+        if (is_server && !frame::get_masked(h)) {
+            return make_error_code(error::masking_required);
+        } else if (!is_server && frame::get_masked(h)) {
+            return make_error_code(error::masking_forbidden);
+        }
+
+        return lib::error_code();
+    }
+
+    /// Validate an incoming extended header
+    /**
+     * Validates an incoming hybi13 full header.
+     *
+     * @todo unit test for the >32 bit frames on 32 bit systems case
+     *
+     * @param h The basic header to validate
+     * @param e The extended header to validate
+     * @return An error_code, non-zero values indicate why the validation
+     * failed
+     */
+    lib::error_code validate_incoming_extended_header(frame::basic_header h,
+        frame::extended_header e) const
+    {
+        uint8_t basic_size = frame::get_basic_size(h);
+        uint64_t payload_size = frame::get_payload_size(h,e);
+
+        // Check for non-minimally encoded payloads
+        if (basic_size == frame::payload_size_code_16bit &&
+            payload_size <= frame::limits::payload_size_basic)
+        {
+            return make_error_code(error::non_minimal_encoding);
+        }
+
+        if (basic_size == frame::payload_size_code_64bit &&
+            payload_size <= frame::limits::payload_size_extended)
+        {
+            return make_error_code(error::non_minimal_encoding);
+        }
+
+        // Check for >32bit frames on 32 bit systems
+        if (sizeof(size_t) == 4 && (payload_size >> 32)) {
+            return make_error_code(error::requires_64bit);
+        }
+
+        return lib::error_code();
+    }
+
+    /// Copy and mask/unmask in one operation
+    /**
+     * Reads input from one string and writes unmasked output to another.
+     *
+     * @param [in] i The input string.
+     * @param [out] o The output string.
+     * @param [in] key The masking key to use for masking/unmasking
+     */
+    void masked_copy (std::string const & i, std::string & o,
+        frame::masking_key_type key) const
+    {
+        frame::byte_mask(i.begin(),i.end(),o.begin(),key);
+        // TODO: SIMD masking
+    }
+
+    /// Generic prepare control frame with opcode and payload.
+    /**
+     * Internal control frame building method. Handles validation, masking, etc
+     *
+     * @param op The control opcode to use
+     * @param payload The payload to use
+     * @param out The message buffer to store the prepared frame in
+     * @return Status code, zero on success, non-zero on error
+     */
+    lib::error_code prepare_control(frame::opcode::value op,
+        std::string const & payload, message_ptr out) const
+    {
+        if (!out) {
+            return make_error_code(error::invalid_arguments);
+        }
+
+        if (!frame::opcode::is_control(op)) {
+            return make_error_code(error::invalid_opcode);
+        }
+
+        if (payload.size() > frame::limits::payload_size_basic) {
+            return make_error_code(error::control_too_big);
+        }
+
+        frame::masking_key_type key;
+        bool masked = !base::m_server;
+
+        frame::basic_header h(op,payload.size(),true,masked);
+
+        std::string & o = out->get_raw_payload();
+        o.resize(payload.size());
+
+        if (masked) {
+            // Generate masking key.
+            key.i = m_rng();
+
+            frame::extended_header e(payload.size(),key.i);
+            out->set_header(frame::prepare_header(h,e));
+            this->masked_copy(payload,o,key);
+        } else {
+            frame::extended_header e(payload.size());
+            out->set_header(frame::prepare_header(h,e));
+            std::copy(payload.begin(),payload.end(),o.begin());
+        }
+    
+        out->set_opcode(op);
+        out->set_prepared(true);
+
+        return lib::error_code();
+    }
+
+    enum state {
+        HEADER_BASIC = 0,
+        HEADER_EXTENDED = 1,
+        EXTENSION = 2,
+        APPLICATION = 3,
+        READY = 4,
+        FATAL_ERROR = 5
+    };
+
+    /// This data structure holds data related to processing a message, such as
+    /// the buffer it is being written to, its masking key, its UTF8 validation
+    /// state, and sometimes its compression state.
+    struct msg_metadata {
+        msg_metadata() {}
+        msg_metadata(message_ptr m, size_t p) : msg_ptr(m),prepared_key(p) {}
+        msg_metadata(message_ptr m, frame::masking_key_type p)
+          : msg_ptr(m)
+          , prepared_key(prepare_masking_key(p)) {}
+
+        message_ptr msg_ptr;        // pointer to the message data buffer
+        size_t      prepared_key;   // prepared masking key
+        utf8_validator::validator validator; // utf8 validation state
+    };
+
+    // Basic header of the frame being read
+    frame::basic_header m_basic_header;
+
+    // Pointer to a manager that can create message buffers for us.
+    msg_manager_ptr m_msg_manager;
+
+    // Number of bytes needed to complete the current operation
+    size_t m_bytes_needed;
+
+    // Number of extended header bytes read
+    size_t m_cursor;
+
+    // Metadata for the current data msg
+    msg_metadata m_data_msg;
+    // Metadata for the current control msg
+    msg_metadata m_control_msg;
+
+    // Pointer to the metadata associated with the frame being read
+    msg_metadata * m_current_msg;
+
+    // Extended header of current frame
+    frame::extended_header m_extended_header;
+
+    rng_type & m_rng;
+
+    // Overall state of the processor
+    state m_state;
+
+    // Extensions
+    permessage_deflate_type m_permessage_deflate;
+};
+
+} // namespace processor
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_PROCESSOR_HYBI13_HPP
diff --git a/subprojects/websocketpp/websocketpp/processors/processor.hpp b/subprojects/websocketpp/websocketpp/processors/processor.hpp
new file mode 100644
index 000000000..5131cc45e
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/processors/processor.hpp
@@ -0,0 +1,407 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_PROCESSOR_HPP
+#define WEBSOCKETPP_PROCESSOR_HPP
+
+#include <websocketpp/processors/base.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <websocketpp/close.hpp>
+#include <websocketpp/utilities.hpp>
+#include <websocketpp/uri.hpp>
+
+#include <sstream>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace websocketpp {
+/// Processors encapsulate the protocol rules specific to each WebSocket version
+/**
+ * The processors namespace includes a number of free functions that operate on
+ * various WebSocket related data structures and perform processing that is not
+ * related to specific versions of the protocol.
+ *
+ * It also includes the abstract interface for the protocol specific processing
+ * engines. These engines wrap all of the logic necessary for parsing and
+ * validating WebSocket handshakes and messages of specific protocol version
+ * and set of allowed extensions.
+ *
+ * An instance of a processor represents the state of a single WebSocket
+ * connection of the associated version. One processor instance is needed per
+ * logical WebSocket connection.
+ */
+namespace processor {
+
+/// Determine whether or not a generic HTTP request is a WebSocket handshake
+/**
+ * @param r The HTTP request to read.
+ *
+ * @return True if the request is a WebSocket handshake, false otherwise
+ */
+template <typename request_type>
+bool is_websocket_handshake(request_type& r) {
+    using utility::ci_find_substr;
+
+    std::string const & upgrade_header = r.get_header("Upgrade");
+
+    if (ci_find_substr(upgrade_header, constants::upgrade_token,
+        sizeof(constants::upgrade_token)-1) == upgrade_header.end())
+    {
+        return false;
+    }
+
+    std::string const & con_header = r.get_header("Connection");
+
+    if (ci_find_substr(con_header, constants::connection_token,
+        sizeof(constants::connection_token)-1) == con_header.end())
+    {
+        return false;
+    }
+
+    return true;
+}
+
+/// Extract the version from a WebSocket handshake request
+/**
+ * A blank version header indicates a spec before versions were introduced.
+ * The only such versions in shipping products are Hixie Draft 75 and Hixie
+ * Draft 76. Draft 75 is present in Chrome 4-5 and Safari 5.0.0, Draft 76 (also
+ * known as hybi 00 is present in Chrome 6-13 and Safari 5.0.1+. As
+ * differentiating between these two sets of browsers is very difficult and
+ * Safari 5.0.1+ accounts for the vast majority of cases in the wild this
+ * function assumes that all handshakes without a valid version header are
+ * Hybi 00.
+ *
+ * @param r The WebSocket handshake request to read.
+ *
+ * @return The WebSocket handshake version or -1 if there was an extraction
+ * error.
+ */
+template <typename request_type>
+int get_websocket_version(request_type& r) {
+    if (!r.ready()) {
+        return -2;
+    }
+    
+    if (r.get_header("Sec-WebSocket-Version").empty()) {
+        return 0;
+    }
+
+    int version;
+    std::istringstream ss(r.get_header("Sec-WebSocket-Version"));
+
+    if ((ss >> version).fail()) {
+        return -1;
+    }
+
+    return version;
+}
+
+/// Extract a URI ptr from the host header of the request
+/**
+ * @param request The request to extract the Host header from.
+ *
+ * @param scheme The scheme under which this request was received (ws, wss,
+ * http, https, etc)
+ *
+ * @return A uri_pointer that encodes the value of the host header.
+ */
+template <typename request_type>
+uri_ptr get_uri_from_host(request_type & request, std::string scheme) {
+    std::string h = request.get_header("Host");
+
+    size_t last_colon = h.rfind(":");
+    size_t last_sbrace = h.rfind("]");
+
+    // no : = hostname with no port
+    // last : before ] = ipv6 literal with no port
+    // : with no ] = hostname with port
+    // : after ] = ipv6 literal with port
+    if (last_colon == std::string::npos ||
+        (last_sbrace != std::string::npos && last_sbrace > last_colon))
+    {
+        return lib::make_shared<uri>(scheme, h, request.get_uri());
+    } else {
+        return lib::make_shared<uri>(scheme,
+                               h.substr(0,last_colon),
+                               h.substr(last_colon+1),
+                               request.get_uri());
+    }
+}
+
+/// WebSocket protocol processor abstract base class
+template <typename config>
+class processor {
+public:
+    typedef processor<config> type;
+    typedef typename config::request_type request_type;
+    typedef typename config::response_type response_type;
+    typedef typename config::message_type::ptr message_ptr;
+    typedef std::pair<lib::error_code,std::string> err_str_pair;
+
+    explicit processor(bool secure, bool p_is_server)
+      : m_secure(secure)
+      , m_server(p_is_server)
+      , m_max_message_size(config::max_message_size)
+    {}
+
+    virtual ~processor() {}
+
+    /// Get the protocol version of this processor
+    virtual int get_version() const = 0;
+
+    /// Get maximum message size
+    /**
+     * Get maximum message size. Maximum message size determines the point at which the
+     * processor will fail a connection with the message_too_big protocol error.
+     *
+     * The default is retrieved from the max_message_size value from the template config
+     *
+     * @since 0.3.0
+     */
+    size_t get_max_message_size() const {
+        return m_max_message_size;
+    }
+    
+    /// Set maximum message size
+    /**
+     * Set maximum message size. Maximum message size determines the point at which the
+     * processor will fail a connection with the message_too_big protocol error.
+     *
+     * The default is retrieved from the max_message_size value from the template config
+     *
+     * @since 0.3.0
+     *
+     * @param new_value The value to set as the maximum message size.
+     */
+    void set_max_message_size(size_t new_value) {
+        m_max_message_size = new_value;
+    }
+
+    /// Returns whether or not the permessage_compress extension is implemented
+    /**
+     * Compile time flag that indicates whether this processor has implemented
+     * the permessage_compress extension. By default this is false.
+     */
+    virtual bool has_permessage_compress() const {
+        return false;
+    }
+
+    /// Initializes extensions based on the Sec-WebSocket-Extensions header
+    /**
+     * Reads the Sec-WebSocket-Extensions header and determines if any of the
+     * requested extensions are supported by this processor. If they are their
+     * settings data is initialized and an extension string to send to the
+     * is returned.
+     *
+     * @param request The request or response headers to look at.
+     */
+    virtual err_str_pair negotiate_extensions(request_type const &) {
+        return err_str_pair();
+    }
+    
+    /// Initializes extensions based on the Sec-WebSocket-Extensions header
+    /**
+     * Reads the Sec-WebSocket-Extensions header and determines if any of the
+     * requested extensions were accepted by the server. If they are their
+     * settings data is initialized. If they are not a list of required
+     * extensions (if any) is returned. This list may be sent back to the server
+     * as a part of the 1010/Extension required close code.
+     *
+     * @param response The request or response headers to look at.
+     */
+    virtual err_str_pair negotiate_extensions(response_type const &) {
+        return err_str_pair();
+    }
+
+    /// validate a WebSocket handshake request for this version
+    /**
+     * @param request The WebSocket handshake request to validate.
+     * is_websocket_handshake(request) must be true and
+     * get_websocket_version(request) must equal this->get_version().
+     *
+     * @return A status code, 0 on success, non-zero for specific sorts of
+     * failure
+     */
+    virtual lib::error_code validate_handshake(request_type const & request) const = 0;
+
+    /// Calculate the appropriate response for this websocket request
+    /**
+     * @param req The request to process
+     *
+     * @param subprotocol The subprotocol in use
+     *
+     * @param res The response to store the processed response in
+     *
+     * @return An error code, 0 on success, non-zero for other errors
+     */
+    virtual lib::error_code process_handshake(request_type const & req,
+        std::string const & subprotocol, response_type& res) const = 0;
+
+    /// Fill in an HTTP request for an outgoing connection handshake
+    /**
+     * @param req The request to process.
+     *
+     * @return An error code, 0 on success, non-zero for other errors
+     */
+    virtual lib::error_code client_handshake_request(request_type & req,
+        uri_ptr uri, std::vector<std::string> const & subprotocols) const = 0;
+
+    /// Validate the server's response to an outgoing handshake request
+    /**
+     * @param req The original request sent
+     * @param res The reponse to generate
+     * @return An error code, 0 on success, non-zero for other errors
+     */
+    virtual lib::error_code validate_server_handshake_response(request_type
+        const & req, response_type & res) const = 0;
+
+    /// Given a completed response, get the raw bytes to put on the wire
+    virtual std::string get_raw(response_type const & request) const = 0;
+
+    /// Return the value of the header containing the CORS origin.
+    virtual std::string const & get_origin(request_type const & request) const = 0;
+
+    /// Extracts requested subprotocols from a handshake request
+    /**
+     * Extracts a list of all subprotocols that the client has requested in the
+     * given opening handshake request.
+     *
+     * @param [in] req The request to extract from
+     * @param [out] subprotocol_list A reference to a vector of strings to store
+     * the results in.
+     */
+    virtual lib::error_code extract_subprotocols(const request_type & req,
+        std::vector<std::string> & subprotocol_list) = 0;
+
+    /// Extracts client uri from a handshake request
+    virtual uri_ptr get_uri(request_type const & request) const = 0;
+
+    /// process new websocket connection bytes
+    /**
+     * WebSocket connections are a continous stream of bytes that must be
+     * interpreted by a protocol processor into discrete frames.
+     *
+     * @param buf Buffer from which bytes should be read.
+     * @param len Length of buffer
+     * @param ec Reference to an error code to return any errors in
+     * @return Number of bytes processed
+     */
+    virtual size_t consume(uint8_t *buf, size_t len, lib::error_code & ec) = 0;
+
+    /// Checks if there is a message ready
+    /**
+     * Checks if the most recent consume operation processed enough bytes to
+     * complete a new WebSocket message. The message can be retrieved by calling
+     * get_message() which will reset the internal state to not-ready and allow
+     * consume to read more bytes.
+     *
+     * @return Whether or not a message is ready.
+     */
+    virtual bool ready() const = 0;
+
+    /// Retrieves the most recently processed message
+    /**
+     * Retrieves a shared pointer to the recently completed message if there is
+     * one. If ready() returns true then there is a message available.
+     * Retrieving the message with get_message will reset the state of ready.
+     * As such, each new message may be retrieved only once. Calling get_message
+     * when there is no message available will result in a null pointer being
+     * returned.
+     *
+     * @return A pointer to the most recently processed message or a null shared
+     *         pointer.
+     */
+    virtual message_ptr get_message() = 0;
+
+    /// Tests whether the processor is in a fatal error state
+    virtual bool get_error() const = 0;
+
+    /// Retrieves the number of bytes presently needed by the processor
+    /// This value may be used as a hint to the transport layer as to how many
+    /// bytes to wait for before running consume again.
+    virtual size_t get_bytes_needed() const {
+        return 1;
+    }
+
+    /// Prepare a data message for writing
+    /**
+     * Performs validation, masking, compression, etc. will return an error if
+     * there was an error, otherwise msg will be ready to be written
+     */
+    virtual lib::error_code prepare_data_frame(message_ptr in, message_ptr out) = 0;
+
+    /// Prepare a ping frame
+    /**
+     * Ping preparation is entirely state free. There is no payload validation
+     * other than length. Payload need not be UTF-8.
+     *
+     * @param in The string to use for the ping payload
+     * @param out The message buffer to prepare the ping in.
+     * @return Status code, zero on success, non-zero on failure
+     */
+    virtual lib::error_code prepare_ping(std::string const & in, message_ptr out) const 
+        = 0;
+
+    /// Prepare a pong frame
+    /**
+     * Pong preparation is entirely state free. There is no payload validation
+     * other than length. Payload need not be UTF-8.
+     *
+     * @param in The string to use for the pong payload
+     * @param out The message buffer to prepare the pong in.
+     * @return Status code, zero on success, non-zero on failure
+     */
+    virtual lib::error_code prepare_pong(std::string const & in, message_ptr out) const 
+        = 0;
+
+    /// Prepare a close frame
+    /**
+     * Close preparation is entirely state free. The code and reason are both
+     * subject to validation. Reason must be valid UTF-8. Code must be a valid
+     * un-reserved WebSocket close code. Use close::status::no_status to
+     * indicate no code. If no code is supplied a reason may not be specified.
+     *
+     * @param code The close code to send
+     * @param reason The reason string to send
+     * @param out The message buffer to prepare the fame in
+     * @return Status code, zero on success, non-zero on failure
+     */
+    virtual lib::error_code prepare_close(close::status::value code,
+        std::string const & reason, message_ptr out) const = 0;
+protected:
+    bool const m_secure;
+    bool const m_server;
+    size_t m_max_message_size;
+};
+
+} // namespace processor
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_PROCESSOR_HPP
diff --git a/subprojects/websocketpp/websocketpp/random/none.hpp b/subprojects/websocketpp/websocketpp/random/none.hpp
new file mode 100644
index 000000000..2163e6f4a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/random/none.hpp
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_RANDOM_NONE_HPP
+#define WEBSOCKETPP_RANDOM_NONE_HPP
+
+namespace websocketpp {
+/// Random number generation policies
+namespace random {
+/// Stub RNG policy that always returns 0
+namespace none {
+
+/// Thread safe stub "random" integer generator.
+/**
+ * This template class provides a random integer stub. The interface mimics the
+ * WebSocket++ RNG generator classes but the generater function always returns
+ * zero. This can be used to stub out the RNG for unit and performance testing.
+ *
+ * Call operator() to generate the next number
+ */
+template <typename int_type>
+class int_generator {
+    public:
+        int_generator() {}
+
+        /// advances the engine's state and returns the generated value
+        int_type operator()() {
+            return 0;
+        }
+};
+
+} // namespace none
+} // namespace random
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_RANDOM_NONE_HPP
diff --git a/subprojects/websocketpp/websocketpp/random/random_device.hpp b/subprojects/websocketpp/websocketpp/random/random_device.hpp
new file mode 100644
index 000000000..91e7dd162
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/random/random_device.hpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_RANDOM_RANDOM_DEVICE_HPP
+#define WEBSOCKETPP_RANDOM_RANDOM_DEVICE_HPP
+
+#include <websocketpp/common/random.hpp>
+
+namespace websocketpp {
+namespace random {
+/// RNG policy based on std::random_device or boost::random_device
+namespace random_device {
+
+/// Thread safe non-deterministic random integer generator.
+/**
+ * This template class provides thread safe non-deterministic random integer
+ * generation. Numbers are produced in a uniformly distributed range from the
+ * smallest to largest value that int_type can store.
+ *
+ * Thread-safety is provided via locking based on the concurrency template
+ * parameter.
+ *
+ * Non-deterministic RNG is provided via websocketpp::lib which uses either
+ * C++11 or Boost 1.47+'s random_device class.
+ *
+ * Call operator() to generate the next number
+ */
+template <typename int_type, typename concurrency>
+class int_generator {
+    public:
+        typedef typename concurrency::scoped_lock_type scoped_lock_type;
+        typedef typename concurrency::mutex_type mutex_type;
+
+        /// constructor
+        //mac TODO: figure out if signed types present a range problem
+        int_generator() {}
+
+        /// advances the engine's state and returns the generated value
+        int_type operator()() {
+            scoped_lock_type guard(m_lock);
+            return m_dis(m_rng);
+        }
+    private:
+
+
+        lib::random_device m_rng;
+        lib::uniform_int_distribution<int_type> m_dis;
+
+        mutex_type m_lock;
+};
+
+} // namespace random_device
+} // namespace random
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_RANDOM_RANDOM_DEVICE_HPP
diff --git a/subprojects/websocketpp/websocketpp/roles/client_endpoint.hpp b/subprojects/websocketpp/websocketpp/roles/client_endpoint.hpp
new file mode 100644
index 000000000..4d0c433b0
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/roles/client_endpoint.hpp
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_CLIENT_ENDPOINT_HPP
+#define WEBSOCKETPP_CLIENT_ENDPOINT_HPP
+
+#include <websocketpp/endpoint.hpp>
+#include <websocketpp/uri.hpp>
+
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/system_error.hpp>
+
+#include <string>
+
+namespace websocketpp {
+
+/// Client endpoint role based on the given config
+/**
+ *
+ */
+template <typename config>
+class client : public endpoint<connection<config>,config> {
+public:
+    /// Type of this endpoint
+    typedef client<config> type;
+
+    /// Type of the endpoint concurrency component
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of the endpoint transport component
+    typedef typename config::transport_type transport_type;
+
+    /// Type of the connections this server will create
+    typedef connection<config> connection_type;
+    /// Type of a shared pointer to the connections this server will create
+    typedef typename connection_type::ptr connection_ptr;
+
+    /// Type of the connection transport component
+    typedef typename transport_type::transport_con_type transport_con_type;
+    /// Type of a shared pointer to the connection transport component
+    typedef typename transport_con_type::ptr transport_con_ptr;
+
+    /// Type of the endpoint component of this server
+    typedef endpoint<connection_type,config> endpoint_type;
+
+    friend class connection<config>;
+
+    explicit client() : endpoint_type(false)
+    {
+        endpoint_type::m_alog->write(log::alevel::devel, "client constructor");
+    }
+
+    /// Get a new connection
+    /**
+     * Creates and returns a pointer to a new connection to the given URI
+     * suitable for passing to connect(connection_ptr). This method allows
+     * applying connection specific settings before performing the opening
+     * handshake.
+     *
+     * @param [in] location URI to open the connection to as a uri_ptr
+     * @param [out] ec An status code indicating failure reasons, if any
+     *
+     * @return A connection_ptr to the new connection
+     */
+    connection_ptr get_connection(uri_ptr location, lib::error_code & ec) {
+        if (location->get_secure() && !transport_type::is_secure()) {
+            ec = error::make_error_code(error::endpoint_not_secure);
+            return connection_ptr();
+        }
+
+        connection_ptr con = endpoint_type::create_connection();
+
+        if (!con) {
+            ec = error::make_error_code(error::con_creation_failed);
+            return con;
+        }
+
+        con->set_uri(location);
+
+        ec = lib::error_code();
+        return con;
+    }
+
+    /// Get a new connection (string version)
+    /**
+     * Creates and returns a pointer to a new connection to the given URI
+     * suitable for passing to connect(connection_ptr). This overload allows
+     * default construction of the uri_ptr from a standard string.
+     *
+     * @param [in] u URI to open the connection to as a string
+     * @param [out] ec An status code indicating failure reasons, if any
+     *
+     * @return A connection_ptr to the new connection
+     */
+    connection_ptr get_connection(std::string const & u, lib::error_code & ec) {
+        uri_ptr location = lib::make_shared<uri>(u);
+
+        if (!location->get_valid()) {
+            ec = error::make_error_code(error::invalid_uri);
+            return connection_ptr();
+        }
+
+        return get_connection(location, ec);
+    }
+
+    /// Begin the connection process for the given connection
+    /**
+     * Initiates the opening connection handshake for connection con. Exact
+     * behavior depends on the underlying transport policy.
+     *
+     * @param con The connection to connect
+     *
+     * @return The pointer to the connection originally passed in.
+     */
+    connection_ptr connect(connection_ptr con) {
+        // Ask transport to perform a connection
+        transport_type::async_connect(
+            lib::static_pointer_cast<transport_con_type>(con),
+            con->get_uri(),
+            lib::bind(
+                &type::handle_connect,
+                this,
+                con,
+                lib::placeholders::_1
+            )
+        );
+
+        return con;
+    }
+private:
+    // handle_connect
+    void handle_connect(connection_ptr con, lib::error_code const & ec) {
+        if (ec) {
+            con->terminate(ec);
+
+            endpoint_type::m_elog->write(log::elevel::rerror,
+                    "handle_connect error: "+ec.message());
+        } else {
+            endpoint_type::m_alog->write(log::alevel::connect,
+                "Successful connection");
+
+            con->start();
+        }
+    }
+};
+
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_CLIENT_ENDPOINT_HPP
diff --git a/subprojects/websocketpp/websocketpp/roles/server_endpoint.hpp b/subprojects/websocketpp/websocketpp/roles/server_endpoint.hpp
new file mode 100644
index 000000000..9cc652f75
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/roles/server_endpoint.hpp
@@ -0,0 +1,195 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_SERVER_ENDPOINT_HPP
+#define WEBSOCKETPP_SERVER_ENDPOINT_HPP
+
+#include <websocketpp/endpoint.hpp>
+
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/system_error.hpp>
+
+namespace websocketpp {
+
+/// Server endpoint role based on the given config
+/**
+ *
+ */
+template <typename config>
+class server : public endpoint<connection<config>,config> {
+public:
+    /// Type of this endpoint
+    typedef server<config> type;
+
+    /// Type of the endpoint concurrency component
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of the endpoint transport component
+    typedef typename config::transport_type transport_type;
+
+    /// Type of the connections this server will create
+    typedef connection<config> connection_type;
+    /// Type of a shared pointer to the connections this server will create
+    typedef typename connection_type::ptr connection_ptr;
+
+    /// Type of the connection transport component
+    typedef typename transport_type::transport_con_type transport_con_type;
+    /// Type of a shared pointer to the connection transport component
+    typedef typename transport_con_type::ptr transport_con_ptr;
+
+    /// Type of the endpoint component of this server
+    typedef endpoint<connection_type,config> endpoint_type;
+
+    friend class connection<config>;
+
+    explicit server() : endpoint_type(true)
+    {
+        endpoint_type::m_alog->write(log::alevel::devel, "server constructor");
+    }
+
+    /// Destructor
+    ~server<config>() {}
+
+#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+    // no copy constructor because endpoints are not copyable
+    server<config>(server<config> &) = delete;
+
+    // no copy assignment operator because endpoints are not copyable
+    server<config> & operator=(server<config> const &) = delete;
+#endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+
+#ifdef _WEBSOCKETPP_MOVE_SEMANTICS_
+    /// Move constructor
+    server<config>(server<config> && o) : endpoint<connection<config>,config>(std::move(o)) {}
+
+#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+    // no move assignment operator because of const member variables
+    server<config> & operator=(server<config> &&) = delete;
+#endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+
+#endif // _WEBSOCKETPP_MOVE_SEMANTICS_
+
+    /// Create and initialize a new connection
+    /**
+     * The connection will be initialized and ready to begin. Call its start()
+     * method to begin the processing loop.
+     *
+     * Note: The connection must either be started or terminated using
+     * connection::terminate in order to avoid memory leaks.
+     *
+     * @return A pointer to the new connection.
+     */
+    connection_ptr get_connection() {
+        return endpoint_type::create_connection();
+    }
+
+    /// Starts the server's async connection acceptance loop (exception free)
+    /**
+     * Initiates the server connection acceptance loop. Must be called after
+     * listen. This method will have no effect until the underlying io_service
+     * starts running. It may be called after the io_service is already running.
+     *
+     * Refer to documentation for the transport policy you are using for
+     * instructions on how to stop this acceptance loop.
+     *
+     * @param [out] ec A status code indicating an error, if any.
+     */
+    void start_accept(lib::error_code & ec) {
+        if (!transport_type::is_listening()) {
+            ec = error::make_error_code(error::async_accept_not_listening);
+            return;
+        }
+        
+        ec = lib::error_code();
+        connection_ptr con = get_connection();
+
+        if (!con) {
+          ec = error::make_error_code(error::con_creation_failed);
+          return;
+        }
+
+        transport_type::async_accept(
+            lib::static_pointer_cast<transport_con_type>(con),
+            lib::bind(&type::handle_accept,this,con,lib::placeholders::_1),
+            ec
+        );
+
+        if (ec && con) {
+            // If the connection was constructed but the accept failed,
+            // terminate the connection to prevent memory leaks
+            con->terminate(lib::error_code());
+        }
+    }
+
+    /// Starts the server's async connection acceptance loop
+    /**
+     * Initiates the server connection acceptance loop. Must be called after
+     * listen. This method will have no effect until the underlying io_service
+     * starts running. It may be called after the io_service is already running.
+     *
+     * Refer to documentation for the transport policy you are using for
+     * instructions on how to stop this acceptance loop.
+     */
+    void start_accept() {
+        lib::error_code ec;
+        start_accept(ec);
+        if (ec) {
+            throw exception(ec);
+        }
+    }
+
+    /// Handler callback for start_accept
+    void handle_accept(connection_ptr con, lib::error_code const & ec) {
+        if (ec) {
+            con->terminate(ec);
+
+            if (ec == error::operation_canceled) {
+                endpoint_type::m_elog->write(log::elevel::info,
+                    "handle_accept error: "+ec.message());
+            } else {
+                endpoint_type::m_elog->write(log::elevel::rerror,
+                    "handle_accept error: "+ec.message());
+            }
+        } else {
+            con->start();
+        }
+
+        lib::error_code start_ec;
+        start_accept(start_ec);
+        if (start_ec == error::async_accept_not_listening) {
+            endpoint_type::m_elog->write(log::elevel::info,
+                "Stopping acceptance of new connections because the underlying transport is no longer listening.");
+        } else if (start_ec) {
+            endpoint_type::m_elog->write(log::elevel::rerror,
+                "Restarting async_accept loop failed: "+ec.message());
+        }
+    }
+};
+
+} // namespace websocketpp
+
+#endif //WEBSOCKETPP_SERVER_ENDPOINT_HPP
diff --git a/subprojects/websocketpp/websocketpp/server.hpp b/subprojects/websocketpp/websocketpp/server.hpp
new file mode 100644
index 000000000..342fa8c54
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/server.hpp
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_SERVER_HPP
+#define WEBSOCKETPP_SERVER_HPP
+
+#include <websocketpp/roles/server_endpoint.hpp>
+
+#endif //WEBSOCKETPP_SERVER_HPP
diff --git a/subprojects/websocketpp/websocketpp/sha1/sha1.hpp b/subprojects/websocketpp/websocketpp/sha1/sha1.hpp
new file mode 100644
index 000000000..6b48d9578
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/sha1/sha1.hpp
@@ -0,0 +1,189 @@
+/*
+*****
+sha1.hpp is a repackaging of the sha1.cpp and sha1.h files from the smallsha1
+library (http://code.google.com/p/smallsha1/) into a single header suitable for
+use as a header only library. This conversion was done by Peter Thorson
+(webmaster@zaphoyd.com) in 2013. All modifications to the code are redistributed
+under the same license as the original, which is listed below.
+*****
+
+ Copyright (c) 2011, Micael Hildenborg
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    * Neither the name of Micael Hildenborg nor the
+      names of its contributors may be used to endorse or promote products
+      derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY Micael Hildenborg ''AS IS'' AND ANY
+ EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL Micael Hildenborg BE LIABLE FOR ANY
+ DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef SHA1_DEFINED
+#define SHA1_DEFINED
+
+namespace websocketpp {
+namespace sha1 {
+
+namespace { // local
+
+// Rotate an integer value to left.
+inline unsigned int rol(unsigned int value, unsigned int steps) {
+    return ((value << steps) | (value >> (32 - steps)));
+}
+
+// Sets the first 16 integers in the buffert to zero.
+// Used for clearing the W buffert.
+inline void clearWBuffert(unsigned int * buffert)
+{
+    for (int pos = 16; --pos >= 0;)
+    {
+        buffert[pos] = 0;
+    }
+}
+
+inline void innerHash(unsigned int * result, unsigned int * w)
+{
+    unsigned int a = result[0];
+    unsigned int b = result[1];
+    unsigned int c = result[2];
+    unsigned int d = result[3];
+    unsigned int e = result[4];
+
+    int round = 0;
+
+    #define sha1macro(func,val) \
+    { \
+        const unsigned int t = rol(a, 5) + (func) + e + val + w[round]; \
+        e = d; \
+        d = c; \
+        c = rol(b, 30); \
+        b = a; \
+        a = t; \
+    }
+
+    while (round < 16)
+    {
+        sha1macro((b & c) | (~b & d), 0x5a827999)
+        ++round;
+    }
+    while (round < 20)
+    {
+        w[round] = rol((w[round - 3] ^ w[round - 8] ^ w[round - 14] ^ w[round - 16]), 1);
+        sha1macro((b & c) | (~b & d), 0x5a827999)
+        ++round;
+    }
+    while (round < 40)
+    {
+        w[round] = rol((w[round - 3] ^ w[round - 8] ^ w[round - 14] ^ w[round - 16]), 1);
+        sha1macro(b ^ c ^ d, 0x6ed9eba1)
+        ++round;
+    }
+    while (round < 60)
+    {
+        w[round] = rol((w[round - 3] ^ w[round - 8] ^ w[round - 14] ^ w[round - 16]), 1);
+        sha1macro((b & c) | (b & d) | (c & d), 0x8f1bbcdc)
+        ++round;
+    }
+    while (round < 80)
+    {
+        w[round] = rol((w[round - 3] ^ w[round - 8] ^ w[round - 14] ^ w[round - 16]), 1);
+        sha1macro(b ^ c ^ d, 0xca62c1d6)
+        ++round;
+    }
+
+    #undef sha1macro
+
+    result[0] += a;
+    result[1] += b;
+    result[2] += c;
+    result[3] += d;
+    result[4] += e;
+}
+
+} // namespace
+
+/// Calculate a SHA1 hash
+/**
+ * @param src points to any kind of data to be hashed.
+ * @param bytelength the number of bytes to hash from the src pointer.
+ * @param hash should point to a buffer of at least 20 bytes of size for storing
+ * the sha1 result in.
+ */
+inline void calc(void const * src, size_t bytelength, unsigned char * hash) {
+    // Init the result array.
+    unsigned int result[5] = { 0x67452301, 0xefcdab89, 0x98badcfe,
+                               0x10325476, 0xc3d2e1f0 };
+
+    // Cast the void src pointer to be the byte array we can work with.
+    unsigned char const * sarray = (unsigned char const *) src;
+
+    // The reusable round buffer
+    unsigned int w[80];
+
+    // Loop through all complete 64byte blocks.
+
+    size_t endCurrentBlock;
+    size_t currentBlock = 0;
+
+    if (bytelength >= 64) {
+        size_t const endOfFullBlocks = bytelength - 64;
+
+        while (currentBlock <= endOfFullBlocks) {
+            endCurrentBlock = currentBlock + 64;
+
+            // Init the round buffer with the 64 byte block data.
+            for (int roundPos = 0; currentBlock < endCurrentBlock; currentBlock += 4)
+            {
+                // This line will swap endian on big endian and keep endian on
+                // little endian.
+                w[roundPos++] = (unsigned int) sarray[currentBlock + 3]
+                        | (((unsigned int) sarray[currentBlock + 2]) << 8)
+                        | (((unsigned int) sarray[currentBlock + 1]) << 16)
+                        | (((unsigned int) sarray[currentBlock]) << 24);
+            }
+            innerHash(result, w);
+        }
+    }
+
+    // Handle the last and not full 64 byte block if existing.
+    endCurrentBlock = bytelength - currentBlock;
+    clearWBuffert(w);
+    size_t lastBlockBytes = 0;
+    for (;lastBlockBytes < endCurrentBlock; ++lastBlockBytes) {
+        w[lastBlockBytes >> 2] |= (unsigned int) sarray[lastBlockBytes + currentBlock] << ((3 - (lastBlockBytes & 3)) << 3);
+    }
+
+    w[lastBlockBytes >> 2] |= 0x80 << ((3 - (lastBlockBytes & 3)) << 3);
+    if (endCurrentBlock >= 56) {
+        innerHash(result, w);
+        clearWBuffert(w);
+    }
+    w[15] = bytelength << 3;
+    innerHash(result, w);
+
+    // Store hash in result pointer, and make sure we get in in the correct
+    // order on both endian models.
+    for (int hashByte = 20; --hashByte >= 0;) {
+        hash[hashByte] = (result[hashByte >> 2] >> (((3 - hashByte) & 0x3) << 3)) & 0xff;
+    }
+}
+
+} // namespace sha1
+} // namespace websocketpp
+
+#endif // SHA1_DEFINED
diff --git a/subprojects/websocketpp/websocketpp/transport/asio/base.hpp b/subprojects/websocketpp/websocketpp/transport/asio/base.hpp
new file mode 100644
index 000000000..b945fe11f
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/asio/base.hpp
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_ASIO_BASE_HPP
+#define WEBSOCKETPP_TRANSPORT_ASIO_BASE_HPP
+
+#include <websocketpp/common/asio.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/functional.hpp>
+#include <websocketpp/common/system_error.hpp>
+#include <websocketpp/common/type_traits.hpp>
+
+#include <string>
+
+namespace websocketpp {
+namespace transport {
+/// Transport policy that uses asio
+/**
+ * This policy uses a single asio io_service to provide transport
+ * services to a WebSocket++ endpoint.
+ */
+namespace asio {
+
+// Class to manage the memory to be used for handler-based custom allocation.
+// It contains a single block of memory which may be returned for allocation
+// requests. If the memory is in use when an allocation request is made, the
+// allocator delegates allocation to the global heap.
+class handler_allocator {
+public:
+    static const size_t size = 1024;
+    
+    handler_allocator() : m_in_use(false) {}
+
+#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+	handler_allocator(handler_allocator const & cpy) = delete;
+	handler_allocator & operator =(handler_allocator const &) = delete;
+#endif
+
+    void * allocate(std::size_t memsize) {
+        if (!m_in_use && memsize < size) {
+            m_in_use = true;
+            return static_cast<void*>(&m_storage);
+        } else {
+            return ::operator new(memsize);
+        }
+    }
+
+    void deallocate(void * pointer) {
+        if (pointer == &m_storage) {
+            m_in_use = false;
+        } else {
+            ::operator delete(pointer);
+        }
+    }
+
+private:
+    // Storage space used for handler-based custom memory allocation.
+    lib::aligned_storage<size>::type m_storage;
+
+    // Whether the handler-based custom allocation storage has been used.
+    bool m_in_use;
+};
+
+// Wrapper class template for handler objects to allow handler memory
+// allocation to be customised. Calls to operator() are forwarded to the
+// encapsulated handler.
+template <typename Handler>
+class custom_alloc_handler {
+public:
+    custom_alloc_handler(handler_allocator& a, Handler h)
+      : allocator_(a),
+        handler_(h)
+    {}
+
+    template <typename Arg1>
+    void operator()(Arg1 arg1) {
+        handler_(arg1);
+    }
+
+    template <typename Arg1, typename Arg2>
+    void operator()(Arg1 arg1, Arg2 arg2) {
+        handler_(arg1, arg2);
+    }
+
+    friend void* asio_handler_allocate(std::size_t size,
+        custom_alloc_handler<Handler> * this_handler)
+    {
+        return this_handler->allocator_.allocate(size);
+    }
+
+    friend void asio_handler_deallocate(void* pointer, std::size_t /*size*/,
+        custom_alloc_handler<Handler> * this_handler)
+    {
+        this_handler->allocator_.deallocate(pointer);
+    }
+
+private:
+    handler_allocator & allocator_;
+    Handler handler_;
+};
+
+// Helper function to wrap a handler object to add custom allocation.
+template <typename Handler>
+inline custom_alloc_handler<Handler> make_custom_alloc_handler(
+    handler_allocator & a, Handler h)
+{
+    return custom_alloc_handler<Handler>(a, h);
+}
+
+
+
+
+
+
+
+// Forward declaration of class endpoint so that it can be friended/referenced
+// before being included.
+template <typename config>
+class endpoint;
+
+typedef lib::function<void (lib::asio::error_code const & ec,
+    size_t bytes_transferred)> async_read_handler;
+
+typedef lib::function<void (lib::asio::error_code const & ec,
+    size_t bytes_transferred)> async_write_handler;
+
+typedef lib::function<void (lib::error_code const & ec)> pre_init_handler;
+
+// handle_timer: dynamic parameters, multiple copies
+// handle_proxy_write
+// handle_proxy_read
+// handle_async_write
+// handle_pre_init
+
+
+/// Asio transport errors
+namespace error {
+enum value {
+    /// Catch-all error for transport policy errors that don't fit in other
+    /// categories
+    general = 1,
+
+    /// async_read_at_least call requested more bytes than buffer can store
+    invalid_num_bytes,
+
+    /// there was an error in the underlying transport library
+    pass_through,
+
+    /// The connection to the requested proxy server failed
+    proxy_failed,
+
+    /// Invalid Proxy URI
+    proxy_invalid,
+
+    /// Invalid host or service
+    invalid_host_service
+};
+
+/// Asio transport error category
+class category : public lib::error_category {
+public:
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.transport.asio";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case error::general:
+                return "Generic asio transport policy error";
+            case error::invalid_num_bytes:
+                return "async_read_at_least call requested more bytes than buffer can store";
+            case error::pass_through:
+                return "Underlying Transport Error";
+            case error::proxy_failed:
+                return "Proxy connection failed";
+            case error::proxy_invalid:
+                return "Invalid proxy URI";
+            case error::invalid_host_service:
+                return "Invalid host or service";
+            default:
+                return "Unknown";
+        }
+    }
+};
+
+/// Get a reference to a static copy of the asio transport error category
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+/// Create an error code with the given value and the asio transport category
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace asio
+} // namespace transport
+} // namespace websocketpp
+
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum<websocketpp::transport::asio::error::value>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+#endif // WEBSOCKETPP_TRANSPORT_ASIO_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/asio/connection.hpp b/subprojects/websocketpp/websocketpp/transport/asio/connection.hpp
new file mode 100644
index 000000000..60f88a79f
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/asio/connection.hpp
@@ -0,0 +1,1197 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_ASIO_CON_HPP
+#define WEBSOCKETPP_TRANSPORT_ASIO_CON_HPP
+
+#include <websocketpp/transport/asio/base.hpp>
+
+#include <websocketpp/transport/base/connection.hpp>
+
+#include <websocketpp/logger/levels.hpp>
+#include <websocketpp/http/constants.hpp>
+
+#include <websocketpp/base64/base64.hpp>
+#include <websocketpp/error.hpp>
+#include <websocketpp/uri.hpp>
+
+#include <websocketpp/common/asio.hpp>
+#include <websocketpp/common/chrono.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/common/functional.hpp>
+#include <websocketpp/common/connection_hdl.hpp>
+
+#include <istream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace transport {
+namespace asio {
+
+typedef lib::function<void(connection_hdl)> tcp_init_handler;
+
+/// Asio based connection transport component
+/**
+ * transport::asio::connection implements a connection transport component using
+ * Asio that works with the transport::asio::endpoint endpoint transport
+ * component.
+ */
+template <typename config>
+class connection : public config::socket_type::socket_con_type {
+public:
+    /// Type of this connection transport component
+    typedef connection<config> type;
+    /// Type of a shared pointer to this connection transport component
+    typedef lib::shared_ptr<type> ptr;
+
+    /// Type of the socket connection component
+    typedef typename config::socket_type::socket_con_type socket_con_type;
+    /// Type of a shared pointer to the socket connection component
+    typedef typename socket_con_type::ptr socket_con_ptr;
+    /// Type of this transport's access logging policy
+    typedef typename config::alog_type alog_type;
+    /// Type of this transport's error logging policy
+    typedef typename config::elog_type elog_type;
+
+    typedef typename config::request_type request_type;
+    typedef typename request_type::ptr request_ptr;
+    typedef typename config::response_type response_type;
+    typedef typename response_type::ptr response_ptr;
+
+    /// Type of a pointer to the Asio io_service being used
+    typedef lib::asio::io_service * io_service_ptr;
+    /// Type of a pointer to the Asio io_service::strand being used
+    typedef lib::shared_ptr<lib::asio::io_service::strand> strand_ptr;
+    /// Type of a pointer to the Asio timer class
+    typedef lib::shared_ptr<lib::asio::steady_timer> timer_ptr;
+
+    // connection is friends with its associated endpoint to allow the endpoint
+    // to call private/protected utility methods that we don't want to expose
+    // to the public api.
+    friend class endpoint<config>;
+
+    // generate and manage our own io_service
+    explicit connection(bool is_server, const lib::shared_ptr<alog_type> & alog, const lib::shared_ptr<elog_type> & elog)
+      : m_is_server(is_server)
+      , m_alog(alog)
+      , m_elog(elog)
+    {
+        m_alog->write(log::alevel::devel,"asio con transport constructor");
+    }
+
+    /// Get a shared pointer to this component
+    ptr get_shared() {
+        return lib::static_pointer_cast<type>(socket_con_type::get_shared());
+    }
+
+    bool is_secure() const {
+        return socket_con_type::is_secure();
+    }
+
+    /// Set uri hook
+    /**
+     * Called by the endpoint as a connection is being established to provide
+     * the uri being connected to to the transport layer.
+     *
+     * This transport policy doesn't use the uri except to forward it to the 
+     * socket layer.
+     *
+     * @since 0.6.0
+     *
+     * @param u The uri to set
+     */
+    void set_uri(uri_ptr u) {
+        socket_con_type::set_uri(u);
+    }
+
+    /// Sets the tcp pre init handler
+    /**
+     * The tcp pre init handler is called after the raw tcp connection has been
+     * established but before any additional wrappers (proxy connects, TLS
+     * handshakes, etc) have been performed.
+     *
+     * @since 0.3.0
+     *
+     * @param h The handler to call on tcp pre init.
+     */
+    void set_tcp_pre_init_handler(tcp_init_handler h) {
+        m_tcp_pre_init_handler = h;
+    }
+
+    /// Sets the tcp pre init handler (deprecated)
+    /**
+     * The tcp pre init handler is called after the raw tcp connection has been
+     * established but before any additional wrappers (proxy connects, TLS
+     * handshakes, etc) have been performed.
+     *
+     * @deprecated Use set_tcp_pre_init_handler instead
+     *
+     * @param h The handler to call on tcp pre init.
+     */
+    void set_tcp_init_handler(tcp_init_handler h) {
+        set_tcp_pre_init_handler(h);
+    }
+
+    /// Sets the tcp post init handler
+    /**
+     * The tcp post init handler is called after the tcp connection has been
+     * established and all additional wrappers (proxy connects, TLS handshakes,
+     * etc have been performed. This is fired before any bytes are read or any
+     * WebSocket specific handshake logic has been performed.
+     *
+     * @since 0.3.0
+     *
+     * @param h The handler to call on tcp post init.
+     */
+    void set_tcp_post_init_handler(tcp_init_handler h) {
+        m_tcp_post_init_handler = h;
+    }
+
+    /// Set the proxy to connect through (exception free)
+    /**
+     * The URI passed should be a complete URI including scheme. For example:
+     * http://proxy.example.com:8080/
+     *
+     * The proxy must be set up as an explicit (CONNECT) proxy allowed to
+     * connect to the port you specify. Traffic to the proxy is not encrypted.
+     *
+     * @param uri The full URI of the proxy to connect to.
+     *
+     * @param ec A status value
+     */
+    void set_proxy(std::string const & uri, lib::error_code & ec) {
+        // TODO: return errors for illegal URIs here?
+        // TODO: should https urls be illegal for the moment?
+        m_proxy = uri;
+        m_proxy_data = lib::make_shared<proxy_data>();
+        ec = lib::error_code();
+    }
+
+    /// Set the proxy to connect through (exception)
+    void set_proxy(std::string const & uri) {
+        lib::error_code ec;
+        set_proxy(uri,ec);
+        if (ec) { throw exception(ec); }
+    }
+
+    /// Set the basic auth credentials to use (exception free)
+    /**
+     * The URI passed should be a complete URI including scheme. For example:
+     * http://proxy.example.com:8080/
+     *
+     * The proxy must be set up as an explicit proxy
+     *
+     * @param username The username to send
+     *
+     * @param password The password to send
+     *
+     * @param ec A status value
+     */
+    void set_proxy_basic_auth(std::string const & username, std::string const &
+        password, lib::error_code & ec)
+    {
+        if (!m_proxy_data) {
+            ec = make_error_code(websocketpp::error::invalid_state);
+            return;
+        }
+
+        // TODO: username can't contain ':'
+        std::string val = "Basic "+base64_encode(username + ":" + password);
+        m_proxy_data->req.replace_header("Proxy-Authorization",val);
+        ec = lib::error_code();
+    }
+
+    /// Set the basic auth credentials to use (exception)
+    void set_proxy_basic_auth(std::string const & username, std::string const &
+        password)
+    {
+        lib::error_code ec;
+        set_proxy_basic_auth(username,password,ec);
+        if (ec) { throw exception(ec); }
+    }
+
+    /// Set the proxy timeout duration (exception free)
+    /**
+     * Duration is in milliseconds. Default value is based on the transport
+     * config
+     *
+     * @param duration The number of milliseconds to wait before aborting the
+     * proxy connection.
+     *
+     * @param ec A status value
+     */
+    void set_proxy_timeout(long duration, lib::error_code & ec) {
+        if (!m_proxy_data) {
+            ec = make_error_code(websocketpp::error::invalid_state);
+            return;
+        }
+
+        m_proxy_data->timeout_proxy = duration;
+        ec = lib::error_code();
+    }
+
+    /// Set the proxy timeout duration (exception)
+    void set_proxy_timeout(long duration) {
+        lib::error_code ec;
+        set_proxy_timeout(duration,ec);
+        if (ec) { throw exception(ec); }
+    }
+
+    std::string const & get_proxy() const {
+        return m_proxy;
+    }
+
+    /// Get the remote endpoint address
+    /**
+     * The iostream transport has no information about the ultimate remote
+     * endpoint. It will return the string "iostream transport". To indicate
+     * this.
+     *
+     * TODO: allow user settable remote endpoint addresses if this seems useful
+     *
+     * @return A string identifying the address of the remote endpoint
+     */
+    std::string get_remote_endpoint() const {
+        lib::error_code ec;
+
+        std::string ret = socket_con_type::get_remote_endpoint(ec);
+
+        if (ec) {
+            m_elog->write(log::elevel::info,ret);
+            return "Unknown";
+        } else {
+            return ret;
+        }
+    }
+
+    /// Get the connection handle
+    connection_hdl get_handle() const {
+        return m_connection_hdl;
+    }
+
+    /// Call back a function after a period of time.
+    /**
+     * Sets a timer that calls back a function after the specified period of
+     * milliseconds. Returns a handle that can be used to cancel the timer.
+     * A cancelled timer will return the error code error::operation_aborted
+     * A timer that expired will return no error.
+     *
+     * @param duration Length of time to wait in milliseconds
+     *
+     * @param callback The function to call back when the timer has expired
+     *
+     * @return A handle that can be used to cancel the timer if it is no longer
+     * needed.
+     */
+    timer_ptr set_timer(long duration, timer_handler callback) {
+        timer_ptr new_timer = lib::make_shared<lib::asio::steady_timer>(
+            lib::ref(*m_io_service),
+            lib::asio::milliseconds(duration)
+        );
+
+        if (config::enable_multithreading) {
+            new_timer->async_wait(m_strand->wrap(lib::bind(
+                &type::handle_timer, get_shared(),
+                new_timer,
+                callback,
+                lib::placeholders::_1
+            )));
+        } else {
+            new_timer->async_wait(lib::bind(
+                &type::handle_timer, get_shared(),
+                new_timer,
+                callback,
+                lib::placeholders::_1
+            ));
+        }
+
+        return new_timer;
+    }
+
+    /// Timer callback
+    /**
+     * The timer pointer is included to ensure the timer isn't destroyed until
+     * after it has expired.
+     *
+     * TODO: candidate for protected status
+     *
+     * @param post_timer Pointer to the timer in question
+     * @param callback The function to call back
+     * @param ec The status code
+     */
+    void handle_timer(timer_ptr, timer_handler callback,
+        lib::asio::error_code const & ec)
+    {
+        if (ec) {
+            if (ec == lib::asio::error::operation_aborted) {
+                callback(make_error_code(transport::error::operation_aborted));
+            } else {
+                log_err(log::elevel::info,"asio handle_timer",ec);
+                callback(make_error_code(error::pass_through));
+            }
+        } else {
+            callback(lib::error_code());
+        }
+    }
+
+    /// Get a pointer to this connection's strand
+    strand_ptr get_strand() {
+        return m_strand;
+    }
+
+    /// Get the internal transport error code for a closed/failed connection
+    /**
+     * Retrieves a machine readable detailed error code indicating the reason
+     * that the connection was closed or failed. Valid only after the close or
+     * fail handler is called.
+     *
+     * Primarily used if you are using mismatched asio / system_error
+     * implementations such as `boost::asio` with `std::system_error`. In these
+     * cases the transport error type is different than the library error type
+     * and some WebSocket++ functions that return transport errors via the 
+     * library error code type will be coerced into a catch all `pass_through`
+     * or `tls_error` error. This method will return the original machine 
+     * readable transport error in the native type.
+     *
+     * @since 0.7.0
+     *
+     * @return Error code indicating the reason the connection was closed or 
+     * failed
+     */
+    lib::asio::error_code get_transport_ec() const {
+        return m_tec;
+    }
+
+    /// Initialize transport for reading
+    /**
+     * init_asio is called once immediately after construction to initialize
+     * Asio components to the io_service
+     *
+     * The transport initialization sequence consists of the following steps:
+     * - Pre-init: the underlying socket is initialized to the point where
+     * bytes may be written. No bytes are actually written in this stage
+     * - Proxy negotiation: if a proxy is set, a request is made to it to start
+     * a tunnel to the final destination. This stage ends when the proxy is
+     * ready to forward the
+     * next byte to the remote endpoint.
+     * - Post-init: Perform any i/o with the remote endpoint, such as setting up
+     * tunnels for encryption. This stage ends when the connection is ready to
+     * read or write the WebSocket handshakes. At this point the original
+     * callback function is called.
+     */
+protected:
+    void init(init_handler callback) {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,"asio connection init");
+        }
+
+        // TODO: pre-init timeout. Right now no implemented socket policies
+        // actually have an asyncronous pre-init
+
+        socket_con_type::pre_init(
+            lib::bind(
+                &type::handle_pre_init,
+                get_shared(),
+                callback,
+                lib::placeholders::_1
+            )
+        );
+    }
+
+    /// initialize the proxy buffers and http parsers
+    /**
+     *
+     * @param authority The address of the server we want the proxy to tunnel to
+     * in the format of a URI authority (host:port)
+     *
+     * @return Status code indicating what errors occurred, if any
+     */
+    lib::error_code proxy_init(std::string const & authority) {
+        if (!m_proxy_data) {
+            return websocketpp::error::make_error_code(
+                websocketpp::error::invalid_state);
+        }
+        m_proxy_data->req.set_version("HTTP/1.1");
+        m_proxy_data->req.set_method("CONNECT");
+
+        m_proxy_data->req.set_uri(authority);
+        m_proxy_data->req.replace_header("Host",authority);
+
+        return lib::error_code();
+    }
+
+    /// Finish constructing the transport
+    /**
+     * init_asio is called once immediately after construction to initialize
+     * Asio components to the io_service.
+     *
+     * @param io_service A pointer to the io_service to register with this
+     * connection
+     *
+     * @return Status code for the success or failure of the initialization
+     */
+    lib::error_code init_asio (io_service_ptr io_service) {
+        m_io_service = io_service;
+
+        if (config::enable_multithreading) {
+            m_strand = lib::make_shared<lib::asio::io_service::strand>(
+                lib::ref(*io_service));
+        }
+
+        lib::error_code ec = socket_con_type::init_asio(io_service, m_strand,
+            m_is_server);
+
+        return ec;
+    }
+
+    void handle_pre_init(init_handler callback, lib::error_code const & ec) {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,"asio connection handle pre_init");
+        }
+
+        if (m_tcp_pre_init_handler) {
+            m_tcp_pre_init_handler(m_connection_hdl);
+        }
+
+        if (ec) {
+            callback(ec);
+        }
+
+        // If we have a proxy set issue a proxy connect, otherwise skip to
+        // post_init
+        if (!m_proxy.empty()) {
+            proxy_write(callback);
+        } else {
+            post_init(callback);
+        }
+    }
+
+    void post_init(init_handler callback) {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,"asio connection post_init");
+        }
+
+        timer_ptr post_timer;
+        
+        if (config::timeout_socket_post_init > 0) {
+            post_timer = set_timer(
+                config::timeout_socket_post_init,
+                lib::bind(
+                    &type::handle_post_init_timeout,
+                    get_shared(),
+                    post_timer,
+                    callback,
+                    lib::placeholders::_1
+                )
+            );
+        }
+
+        socket_con_type::post_init(
+            lib::bind(
+                &type::handle_post_init,
+                get_shared(),
+                post_timer,
+                callback,
+                lib::placeholders::_1
+            )
+        );
+    }
+
+    /// Post init timeout callback
+    /**
+     * The timer pointer is included to ensure the timer isn't destroyed until
+     * after it has expired.
+     *
+     * @param post_timer Pointer to the timer in question
+     * @param callback The function to call back
+     * @param ec The status code
+     */
+    void handle_post_init_timeout(timer_ptr, init_handler callback,
+        lib::error_code const & ec)
+    {
+        lib::error_code ret_ec;
+
+        if (ec) {
+            if (ec == transport::error::operation_aborted) {
+                m_alog->write(log::alevel::devel,
+                    "asio post init timer cancelled");
+                return;
+            }
+
+            log_err(log::elevel::devel,"asio handle_post_init_timeout",ec);
+            ret_ec = ec;
+        } else {
+            if (socket_con_type::get_ec()) {
+                ret_ec = socket_con_type::get_ec();
+            } else {
+                ret_ec = make_error_code(transport::error::timeout);
+            }
+        }
+
+        m_alog->write(log::alevel::devel, "Asio transport post-init timed out");
+        cancel_socket_checked();
+        callback(ret_ec);
+    }
+
+    /// Post init timeout callback
+    /**
+     * The timer pointer is included to ensure the timer isn't destroyed until
+     * after it has expired.
+     *
+     * @param post_timer Pointer to the timer in question
+     * @param callback The function to call back
+     * @param ec The status code
+     */
+    void handle_post_init(timer_ptr post_timer, init_handler callback,
+        lib::error_code const & ec)
+    {
+        if (ec == transport::error::operation_aborted ||
+            (post_timer && lib::asio::is_neg(post_timer->expires_from_now())))
+        {
+            m_alog->write(log::alevel::devel,"post_init cancelled");
+            return;
+        }
+
+        if (post_timer) {
+            post_timer->cancel();
+        }
+
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,"asio connection handle_post_init");
+        }
+
+        if (m_tcp_post_init_handler) {
+            m_tcp_post_init_handler(m_connection_hdl);
+        }
+
+        callback(ec);
+    }
+
+    void proxy_write(init_handler callback) {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,"asio connection proxy_write");
+        }
+
+        if (!m_proxy_data) {
+            m_elog->write(log::elevel::library,
+                "assertion failed: !m_proxy_data in asio::connection::proxy_write");
+            callback(make_error_code(error::general));
+            return;
+        }
+
+        m_proxy_data->write_buf = m_proxy_data->req.raw();
+
+        m_bufs.push_back(lib::asio::buffer(m_proxy_data->write_buf.data(),
+                                           m_proxy_data->write_buf.size()));
+
+        m_alog->write(log::alevel::devel,m_proxy_data->write_buf);
+
+        // Set a timer so we don't wait forever for the proxy to respond
+        m_proxy_data->timer = this->set_timer(
+            m_proxy_data->timeout_proxy,
+            lib::bind(
+                &type::handle_proxy_timeout,
+                get_shared(),
+                callback,
+                lib::placeholders::_1
+            )
+        );
+
+        // Send proxy request
+        if (config::enable_multithreading) {
+            lib::asio::async_write(
+                socket_con_type::get_next_layer(),
+                m_bufs,
+                m_strand->wrap(lib::bind(
+                    &type::handle_proxy_write, get_shared(),
+                    callback,
+                    lib::placeholders::_1
+                ))
+            );
+        } else {
+            lib::asio::async_write(
+                socket_con_type::get_next_layer(),
+                m_bufs,
+                lib::bind(
+                    &type::handle_proxy_write, get_shared(),
+                    callback,
+                    lib::placeholders::_1
+                )
+            );
+        }
+    }
+
+    void handle_proxy_timeout(init_handler callback, lib::error_code const & ec)
+    {
+        if (ec == transport::error::operation_aborted) {
+            m_alog->write(log::alevel::devel,
+                "asio handle_proxy_write timer cancelled");
+            return;
+        } else if (ec) {
+            log_err(log::elevel::devel,"asio handle_proxy_write",ec);
+            callback(ec);
+        } else {
+            m_alog->write(log::alevel::devel,
+                "asio handle_proxy_write timer expired");
+            cancel_socket_checked();
+            callback(make_error_code(transport::error::timeout));
+        }
+    }
+
+    void handle_proxy_write(init_handler callback,
+        lib::asio::error_code const & ec)
+    {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,
+                "asio connection handle_proxy_write");
+        }
+
+        m_bufs.clear();
+
+        // Timer expired or the operation was aborted for some reason.
+        // Whatever aborted it will be issuing the callback so we are safe to
+        // return
+        if (ec == lib::asio::error::operation_aborted ||
+            lib::asio::is_neg(m_proxy_data->timer->expires_from_now()))
+        {
+            m_elog->write(log::elevel::devel,"write operation aborted");
+            return;
+        }
+
+        if (ec) {
+            log_err(log::elevel::info,"asio handle_proxy_write",ec);
+            m_proxy_data->timer->cancel();
+            callback(make_error_code(error::pass_through));
+            return;
+        }
+
+        proxy_read(callback);
+    }
+
+    void proxy_read(init_handler callback) {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,"asio connection proxy_read");
+        }
+
+        if (!m_proxy_data) {
+            m_elog->write(log::elevel::library,
+                "assertion failed: !m_proxy_data in asio::connection::proxy_read");
+            m_proxy_data->timer->cancel();
+            callback(make_error_code(error::general));
+            return;
+        }
+
+        if (config::enable_multithreading) {
+            lib::asio::async_read_until(
+                socket_con_type::get_next_layer(),
+                m_proxy_data->read_buf,
+                "\r\n\r\n",
+                m_strand->wrap(lib::bind(
+                    &type::handle_proxy_read, get_shared(),
+                    callback,
+                    lib::placeholders::_1, lib::placeholders::_2
+                ))
+            );
+        } else {
+            lib::asio::async_read_until(
+                socket_con_type::get_next_layer(),
+                m_proxy_data->read_buf,
+                "\r\n\r\n",
+                lib::bind(
+                    &type::handle_proxy_read, get_shared(),
+                    callback,
+                    lib::placeholders::_1, lib::placeholders::_2
+                )
+            );
+        }
+    }
+
+    /// Proxy read callback
+    /**
+     * @param init_handler The function to call back
+     * @param ec The status code
+     * @param bytes_transferred The number of bytes read
+     */
+    void handle_proxy_read(init_handler callback,
+        lib::asio::error_code const & ec, size_t)
+    {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,
+                "asio connection handle_proxy_read");
+        }
+
+        // Timer expired or the operation was aborted for some reason.
+        // Whatever aborted it will be issuing the callback so we are safe to
+        // return
+        if (ec == lib::asio::error::operation_aborted ||
+            lib::asio::is_neg(m_proxy_data->timer->expires_from_now()))
+        {
+            m_elog->write(log::elevel::devel,"read operation aborted");
+            return;
+        }
+
+        // At this point there is no need to wait for the timer anymore
+        m_proxy_data->timer->cancel();
+
+        if (ec) {
+            m_elog->write(log::elevel::info,
+                "asio handle_proxy_read error: "+ec.message());
+            callback(make_error_code(error::pass_through));
+        } else {
+            if (!m_proxy_data) {
+                m_elog->write(log::elevel::library,
+                    "assertion failed: !m_proxy_data in asio::connection::handle_proxy_read");
+                callback(make_error_code(error::general));
+                return;
+            }
+
+            std::istream input(&m_proxy_data->read_buf);
+
+            m_proxy_data->res.consume(input);
+
+            if (!m_proxy_data->res.headers_ready()) {
+                // we read until the headers were done in theory but apparently
+                // they aren't. Internal endpoint error.
+                callback(make_error_code(error::general));
+                return;
+            }
+
+            m_alog->write(log::alevel::devel,m_proxy_data->res.raw());
+
+            if (m_proxy_data->res.get_status_code() != http::status_code::ok) {
+                // got an error response back
+                // TODO: expose this error in a programmatically accessible way?
+                // if so, see below for an option on how to do this.
+                std::stringstream s;
+                s << "Proxy connection error: "
+                  << m_proxy_data->res.get_status_code()
+                  << " ("
+                  << m_proxy_data->res.get_status_msg()
+                  << ")";
+                m_elog->write(log::elevel::info,s.str());
+                callback(make_error_code(error::proxy_failed));
+                return;
+            }
+
+            // we have successfully established a connection to the proxy, now
+            // we can continue and the proxy will transparently forward the
+            // WebSocket connection.
+
+            // TODO: decide if we want an on_proxy callback that would allow
+            // access to the proxy response.
+
+            // free the proxy buffers and req/res objects as they aren't needed
+            // anymore
+            m_proxy_data.reset();
+
+            // Continue with post proxy initialization
+            post_init(callback);
+        }
+    }
+
+    /// read at least num_bytes bytes into buf and then call handler.
+    void async_read_at_least(size_t num_bytes, char *buf, size_t len,
+        read_handler handler)
+    {
+        if (m_alog->static_test(log::alevel::devel)) {
+            std::stringstream s;
+            s << "asio async_read_at_least: " << num_bytes;
+            m_alog->write(log::alevel::devel,s.str());
+        }
+
+        // TODO: safety vs speed ?
+        // maybe move into an if devel block
+        /*if (num_bytes > len) {
+            m_elog->write(log::elevel::devel,
+                "asio async_read_at_least error::invalid_num_bytes");
+            handler(make_error_code(transport::error::invalid_num_bytes),
+                size_t(0));
+            return;
+        }*/
+
+        if (config::enable_multithreading) {
+            lib::asio::async_read(
+                socket_con_type::get_socket(),
+                lib::asio::buffer(buf,len),
+                lib::asio::transfer_at_least(num_bytes),
+                m_strand->wrap(make_custom_alloc_handler(
+                    m_read_handler_allocator,
+                    lib::bind(
+                        &type::handle_async_read, get_shared(),
+                        handler,
+                        lib::placeholders::_1, lib::placeholders::_2
+                    )
+                ))
+            );
+        } else {
+            lib::asio::async_read(
+                socket_con_type::get_socket(),
+                lib::asio::buffer(buf,len),
+                lib::asio::transfer_at_least(num_bytes),
+                make_custom_alloc_handler(
+                    m_read_handler_allocator,
+                    lib::bind(
+                        &type::handle_async_read, get_shared(),
+                        handler,
+                        lib::placeholders::_1, lib::placeholders::_2
+                    )
+                )
+            );    
+        }
+        
+    }
+
+    void handle_async_read(read_handler handler, lib::asio::error_code const & ec,
+        size_t bytes_transferred)
+    {
+        m_alog->write(log::alevel::devel, "asio con handle_async_read");
+
+        // translate asio error codes into more lib::error_codes
+        lib::error_code tec;
+        if (ec == lib::asio::error::eof) {
+            tec = make_error_code(transport::error::eof);
+        } else if (ec) {
+            // We don't know much more about the error at this point. As our
+            // socket/security policy if it knows more:
+            tec = socket_con_type::translate_ec(ec);
+            m_tec = ec;
+
+            if (tec == transport::error::tls_error ||
+                tec == transport::error::pass_through)
+            {
+                // These are aggregate/catch all errors. Log some human readable
+                // information to the info channel to give library users some
+                // more details about why the upstream method may have failed.
+                log_err(log::elevel::info,"asio async_read_at_least",ec);
+            }
+        }
+        if (handler) {
+            handler(tec,bytes_transferred);
+        } else {
+            // This can happen in cases where the connection is terminated while
+            // the transport is waiting on a read.
+            m_alog->write(log::alevel::devel,
+                "handle_async_read called with null read handler");
+        }
+    }
+
+    /// Initiate a potentially asyncronous write of the given buffer
+    void async_write(const char* buf, size_t len, write_handler handler) {
+        m_bufs.push_back(lib::asio::buffer(buf,len));
+
+        if (config::enable_multithreading) {
+            lib::asio::async_write(
+                socket_con_type::get_socket(),
+                m_bufs,
+                m_strand->wrap(make_custom_alloc_handler(
+                    m_write_handler_allocator,
+                    lib::bind(
+                        &type::handle_async_write, get_shared(),
+                        handler,
+                        lib::placeholders::_1, lib::placeholders::_2
+                    )
+                ))
+            );
+        } else {
+            lib::asio::async_write(
+                socket_con_type::get_socket(),
+                m_bufs,
+                make_custom_alloc_handler(
+                    m_write_handler_allocator,
+                    lib::bind(
+                        &type::handle_async_write, get_shared(),
+                        handler,
+                        lib::placeholders::_1, lib::placeholders::_2
+                    )
+                )
+            );
+        }
+    }
+
+    /// Initiate a potentially asyncronous write of the given buffers
+    void async_write(std::vector<buffer> const & bufs, write_handler handler) {
+        std::vector<buffer>::const_iterator it;
+
+        for (it = bufs.begin(); it != bufs.end(); ++it) {
+            m_bufs.push_back(lib::asio::buffer((*it).buf,(*it).len));
+        }
+
+        if (config::enable_multithreading) {
+            lib::asio::async_write(
+                socket_con_type::get_socket(),
+                m_bufs,
+                m_strand->wrap(make_custom_alloc_handler(
+                    m_write_handler_allocator,
+                    lib::bind(
+                        &type::handle_async_write, get_shared(),
+                        handler,
+                        lib::placeholders::_1, lib::placeholders::_2
+                    )
+                ))
+            );
+        } else {
+            lib::asio::async_write(
+                socket_con_type::get_socket(),
+                m_bufs,
+                make_custom_alloc_handler(
+                    m_write_handler_allocator,
+                    lib::bind(
+                        &type::handle_async_write, get_shared(),
+                        handler,
+                        lib::placeholders::_1, lib::placeholders::_2
+                    )
+                )
+            );
+        }
+    }
+
+    /// Async write callback
+    /**
+     * @param ec The status code
+     * @param bytes_transferred The number of bytes read
+     */
+    void handle_async_write(write_handler handler, lib::asio::error_code const & ec, size_t) {
+        m_bufs.clear();
+        lib::error_code tec;
+        if (ec) {
+            log_err(log::elevel::info,"asio async_write",ec);
+            tec = make_error_code(transport::error::pass_through);
+        }
+        if (handler) {
+            handler(tec);
+        } else {
+            // This can happen in cases where the connection is terminated while
+            // the transport is waiting on a read.
+            m_alog->write(log::alevel::devel,
+                "handle_async_write called with null write handler");
+        }
+    }
+
+    /// Set Connection Handle
+    /**
+     * See common/connection_hdl.hpp for information
+     *
+     * @param hdl A connection_hdl that the transport will use to refer
+     * to itself
+     */
+    void set_handle(connection_hdl hdl) {
+        m_connection_hdl = hdl;
+        socket_con_type::set_handle(hdl);
+    }
+
+    /// Trigger the on_interrupt handler
+    /**
+     * This needs to be thread safe
+     */
+    lib::error_code interrupt(interrupt_handler handler) {
+        if (config::enable_multithreading) {
+            m_io_service->post(m_strand->wrap(handler));
+        } else {
+            m_io_service->post(handler);
+        }
+        return lib::error_code();
+    }
+
+    lib::error_code dispatch(dispatch_handler handler) {
+        if (config::enable_multithreading) {
+            m_io_service->post(m_strand->wrap(handler));
+        } else {
+            m_io_service->post(handler);
+        }
+        return lib::error_code();
+    }
+
+    /*void handle_interrupt(interrupt_handler handler) {
+        handler();
+    }*/
+
+    /// close and clean up the underlying socket
+    void async_shutdown(shutdown_handler callback) {
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,"asio connection async_shutdown");
+        }
+
+        timer_ptr shutdown_timer;
+        shutdown_timer = set_timer(
+            config::timeout_socket_shutdown,
+            lib::bind(
+                &type::handle_async_shutdown_timeout,
+                get_shared(),
+                shutdown_timer,
+                callback,
+                lib::placeholders::_1
+            )
+        );
+
+        socket_con_type::async_shutdown(
+            lib::bind(
+                &type::handle_async_shutdown,
+                get_shared(),
+                shutdown_timer,
+                callback,
+                lib::placeholders::_1
+            )
+        );
+    }
+
+    /// Async shutdown timeout handler
+    /**
+     * @param shutdown_timer A pointer to the timer to keep it in scope
+     * @param callback The function to call back
+     * @param ec The status code
+     */
+    void handle_async_shutdown_timeout(timer_ptr, init_handler callback, 
+        lib::error_code const & ec)
+    {
+        lib::error_code ret_ec;
+
+        if (ec) {
+            if (ec == transport::error::operation_aborted) {
+                m_alog->write(log::alevel::devel,
+                    "asio socket shutdown timer cancelled");
+                return;
+            }
+
+            log_err(log::elevel::devel,"asio handle_async_shutdown_timeout",ec);
+            ret_ec = ec;
+        } else {
+            ret_ec = make_error_code(transport::error::timeout);
+        }
+
+        m_alog->write(log::alevel::devel,
+            "Asio transport socket shutdown timed out");
+        cancel_socket_checked();
+        callback(ret_ec);
+    }
+
+    void handle_async_shutdown(timer_ptr shutdown_timer, shutdown_handler
+        callback, lib::asio::error_code const & ec)
+    {
+        if (ec == lib::asio::error::operation_aborted ||
+            lib::asio::is_neg(shutdown_timer->expires_from_now()))
+        {
+            m_alog->write(log::alevel::devel,"async_shutdown cancelled");
+            return;
+        }
+
+        shutdown_timer->cancel();
+
+        lib::error_code tec;
+        if (ec) {
+            if (ec == lib::asio::error::not_connected) {
+                // The socket was already closed when we tried to close it. This
+                // happens periodically (usually if a read or write fails
+                // earlier and if it is a real error will be caught at another
+                // level of the stack.
+            } else {
+                // We don't know anything more about this error, give our
+                // socket/security policy a crack at it.
+                tec = socket_con_type::translate_ec(ec);
+                m_tec = ec;
+
+                // all other errors are effectively pass through errors of
+				// some sort so print some detail on the info channel for
+				// library users to look up if needed.
+				log_err(log::elevel::info,"asio async_shutdown",ec);
+            }
+        } else {
+            if (m_alog->static_test(log::alevel::devel)) {
+                m_alog->write(log::alevel::devel,
+                    "asio con handle_async_shutdown");
+            }
+        }
+        callback(tec);
+    }
+
+    /// Cancel the underlying socket and log any errors
+    void cancel_socket_checked() {
+        lib::asio::error_code cec = socket_con_type::cancel_socket();
+        if (cec) {
+            if (cec == lib::asio::error::operation_not_supported) {
+                // cancel not supported on this OS, ignore and log at dev level
+                m_alog->write(log::alevel::devel, "socket cancel not supported");
+            } else {
+                log_err(log::elevel::warn, "socket cancel failed", cec);
+            }
+        }
+    }
+
+private:
+    /// Convenience method for logging the code and message for an error_code
+    template <typename error_type>
+    void log_err(log::level l, const char * msg, const error_type & ec) {
+        std::stringstream s;
+        s << msg << " error: " << ec << " (" << ec.message() << ")";
+        m_elog->write(l,s.str());
+    }
+
+    // static settings
+    const bool m_is_server;
+    lib::shared_ptr<alog_type> m_alog;
+    lib::shared_ptr<elog_type> m_elog;
+
+    struct proxy_data {
+        proxy_data() : timeout_proxy(config::timeout_proxy) {}
+
+        request_type req;
+        response_type res;
+        std::string write_buf;
+        lib::asio::streambuf read_buf;
+        long timeout_proxy;
+        timer_ptr timer;
+    };
+
+    std::string m_proxy;
+    lib::shared_ptr<proxy_data> m_proxy_data;
+
+    // transport resources
+    io_service_ptr  m_io_service;
+    strand_ptr      m_strand;
+    connection_hdl  m_connection_hdl;
+
+    std::vector<lib::asio::const_buffer> m_bufs;
+
+    /// Detailed internal error code
+    lib::asio::error_code m_tec;
+
+    // Handlers
+    tcp_init_handler    m_tcp_pre_init_handler;
+    tcp_init_handler    m_tcp_post_init_handler;
+
+    handler_allocator   m_read_handler_allocator;
+    handler_allocator   m_write_handler_allocator;
+};
+
+
+} // namespace asio
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_ASIO_CON_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/asio/endpoint.hpp b/subprojects/websocketpp/websocketpp/transport/asio/endpoint.hpp
new file mode 100644
index 000000000..ddab2c742
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/asio/endpoint.hpp
@@ -0,0 +1,1186 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_ASIO_HPP
+#define WEBSOCKETPP_TRANSPORT_ASIO_HPP
+
+#include <websocketpp/transport/base/endpoint.hpp>
+#include <websocketpp/transport/asio/connection.hpp>
+#include <websocketpp/transport/asio/security/none.hpp>
+
+#include <websocketpp/uri.hpp>
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/asio.hpp>
+#include <websocketpp/common/functional.hpp>
+
+#include <sstream>
+#include <string>
+
+namespace websocketpp {
+namespace transport {
+namespace asio {
+
+/// Asio based endpoint transport component
+/**
+ * transport::asio::endpoint implements an endpoint transport component using
+ * Asio.
+ */
+template <typename config>
+class endpoint : public config::socket_type {
+public:
+    /// Type of this endpoint transport component
+    typedef endpoint<config> type;
+
+    /// Type of the concurrency policy
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of the socket policy
+    typedef typename config::socket_type socket_type;
+    /// Type of the error logging policy
+    typedef typename config::elog_type elog_type;
+    /// Type of the access logging policy
+    typedef typename config::alog_type alog_type;
+
+    /// Type of the socket connection component
+    typedef typename socket_type::socket_con_type socket_con_type;
+    /// Type of a shared pointer to the socket connection component
+    typedef typename socket_con_type::ptr socket_con_ptr;
+
+    /// Type of the connection transport component associated with this
+    /// endpoint transport component
+    typedef asio::connection<config> transport_con_type;
+    /// Type of a shared pointer to the connection transport component
+    /// associated with this endpoint transport component
+    typedef typename transport_con_type::ptr transport_con_ptr;
+
+    /// Type of a pointer to the ASIO io_service being used
+    typedef lib::asio::io_service * io_service_ptr;
+    /// Type of a shared pointer to the acceptor being used
+    typedef lib::shared_ptr<lib::asio::ip::tcp::acceptor> acceptor_ptr;
+    /// Type of a shared pointer to the resolver being used
+    typedef lib::shared_ptr<lib::asio::ip::tcp::resolver> resolver_ptr;
+    /// Type of timer handle
+    typedef lib::shared_ptr<lib::asio::steady_timer> timer_ptr;
+    /// Type of a shared pointer to an io_service work object
+    typedef lib::shared_ptr<lib::asio::io_service::work> work_ptr;
+
+    /// Type of socket pre-bind handler
+    typedef lib::function<lib::error_code(acceptor_ptr)> tcp_pre_bind_handler;
+
+    // generate and manage our own io_service
+    explicit endpoint()
+      : m_io_service(NULL)
+      , m_external_io_service(false)
+      , m_listen_backlog(lib::asio::socket_base::max_connections)
+      , m_reuse_addr(false)
+      , m_state(UNINITIALIZED)
+    {
+        //std::cout << "transport::asio::endpoint constructor" << std::endl;
+    }
+
+    ~endpoint() {
+        // clean up our io_service if we were initialized with an internal one.
+
+        // Explicitly destroy local objects
+        m_acceptor.reset();
+        m_resolver.reset();
+        m_work.reset();
+        if (m_state != UNINITIALIZED && !m_external_io_service) {
+            delete m_io_service;
+        }
+    }
+
+    /// transport::asio objects are moveable but not copyable or assignable.
+    /// The following code sets this situation up based on whether or not we
+    /// have C++11 support or not
+#ifdef _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+    endpoint(const endpoint & src) = delete;
+    endpoint& operator= (const endpoint & rhs) = delete;
+#else
+private:
+    endpoint(const endpoint & src);
+    endpoint & operator= (const endpoint & rhs);
+public:
+#endif // _WEBSOCKETPP_DEFAULT_DELETE_FUNCTIONS_
+
+#ifdef _WEBSOCKETPP_MOVE_SEMANTICS_
+    endpoint (endpoint && src)
+      : config::socket_type(std::move(src))
+      , m_tcp_pre_init_handler(src.m_tcp_pre_init_handler)
+      , m_tcp_post_init_handler(src.m_tcp_post_init_handler)
+      , m_io_service(src.m_io_service)
+      , m_external_io_service(src.m_external_io_service)
+      , m_acceptor(src.m_acceptor)
+      , m_listen_backlog(lib::asio::socket_base::max_connections)
+      , m_reuse_addr(src.m_reuse_addr)
+      , m_elog(src.m_elog)
+      , m_alog(src.m_alog)
+      , m_state(src.m_state)
+    {
+        src.m_io_service = NULL;
+        src.m_external_io_service = false;
+        src.m_acceptor = NULL;
+        src.m_state = UNINITIALIZED;
+    }
+
+    /*endpoint & operator= (const endpoint && rhs) {
+        if (this != &rhs) {
+            m_io_service = rhs.m_io_service;
+            m_external_io_service = rhs.m_external_io_service;
+            m_acceptor = rhs.m_acceptor;
+            m_listen_backlog = rhs.m_listen_backlog;
+            m_reuse_addr = rhs.m_reuse_addr;
+            m_state = rhs.m_state;
+
+            rhs.m_io_service = NULL;
+            rhs.m_external_io_service = false;
+            rhs.m_acceptor = NULL;
+            rhs.m_listen_backlog = lib::asio::socket_base::max_connections;
+            rhs.m_state = UNINITIALIZED;
+            
+            // TODO: this needs to be updated
+        }
+        return *this;
+    }*/
+#endif // _WEBSOCKETPP_MOVE_SEMANTICS_
+
+    /// Return whether or not the endpoint produces secure connections.
+    bool is_secure() const {
+        return socket_type::is_secure();
+    }
+
+    /// initialize asio transport with external io_service (exception free)
+    /**
+     * Initialize the ASIO transport policy for this endpoint using the provided
+     * io_service object. asio_init must be called exactly once on any endpoint
+     * that uses transport::asio before it can be used.
+     *
+     * @param ptr A pointer to the io_service to use for asio events
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    void init_asio(io_service_ptr ptr, lib::error_code & ec) {
+        if (m_state != UNINITIALIZED) {
+            m_elog->write(log::elevel::library,
+                "asio::init_asio called from the wrong state");
+            using websocketpp::error::make_error_code;
+            ec = make_error_code(websocketpp::error::invalid_state);
+            return;
+        }
+
+        m_alog->write(log::alevel::devel,"asio::init_asio");
+
+        m_io_service = ptr;
+        m_external_io_service = true;
+        m_acceptor = lib::make_shared<lib::asio::ip::tcp::acceptor>(
+            lib::ref(*m_io_service));
+
+        m_state = READY;
+        ec = lib::error_code();
+    }
+
+    /// initialize asio transport with external io_service
+    /**
+     * Initialize the ASIO transport policy for this endpoint using the provided
+     * io_service object. asio_init must be called exactly once on any endpoint
+     * that uses transport::asio before it can be used.
+     *
+     * @param ptr A pointer to the io_service to use for asio events
+     */
+    void init_asio(io_service_ptr ptr) {
+        lib::error_code ec;
+        init_asio(ptr,ec);
+        if (ec) { throw exception(ec); }
+    }
+
+    /// Initialize asio transport with internal io_service (exception free)
+    /**
+     * This method of initialization will allocate and use an internally managed
+     * io_service.
+     *
+     * @see init_asio(io_service_ptr ptr)
+     *
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    void init_asio(lib::error_code & ec) {
+        // Use a smart pointer until the call is successful and ownership has 
+        // successfully been taken. Use unique_ptr when available.
+        // TODO: remove the use of auto_ptr when C++98/03 support is no longer
+        //       necessary.
+#ifdef _WEBSOCKETPP_CPP11_MEMORY_
+        lib::unique_ptr<lib::asio::io_service> service(new lib::asio::io_service());
+#else
+        lib::auto_ptr<lib::asio::io_service> service(new lib::asio::io_service());
+#endif
+        init_asio(service.get(), ec);
+        if( !ec ) service.release(); // Call was successful, transfer ownership
+        m_external_io_service = false;
+    }
+
+    /// Initialize asio transport with internal io_service
+    /**
+     * This method of initialization will allocate and use an internally managed
+     * io_service.
+     *
+     * @see init_asio(io_service_ptr ptr)
+     */
+    void init_asio() {
+        // Use a smart pointer until the call is successful and ownership has 
+        // successfully been taken. Use unique_ptr when available.
+        // TODO: remove the use of auto_ptr when C++98/03 support is no longer
+        //       necessary.
+#ifdef _WEBSOCKETPP_CPP11_MEMORY_
+        lib::unique_ptr<lib::asio::io_service> service(new lib::asio::io_service());
+#else
+        lib::auto_ptr<lib::asio::io_service> service(new lib::asio::io_service());
+#endif
+        init_asio( service.get() );
+        // If control got this far without an exception, then ownership has successfully been taken
+        service.release();
+        m_external_io_service = false;
+    }
+
+    /// Sets the tcp pre bind handler
+    /**
+     * The tcp pre bind handler is called after the listen acceptor has
+     * been created but before the socket bind is performed.
+     *
+     * @since 0.8.0
+     *
+     * @param h The handler to call on tcp pre bind init.
+     */
+    void set_tcp_pre_bind_handler(tcp_pre_bind_handler h) {
+        m_tcp_pre_bind_handler = h;
+    }
+
+    /// Sets the tcp pre init handler
+    /**
+     * The tcp pre init handler is called after the raw tcp connection has been
+     * established but before any additional wrappers (proxy connects, TLS
+     * handshakes, etc) have been performed.
+     *
+     * @since 0.3.0
+     *
+     * @param h The handler to call on tcp pre init.
+     */
+    void set_tcp_pre_init_handler(tcp_init_handler h) {
+        m_tcp_pre_init_handler = h;
+    }
+
+    /// Sets the tcp pre init handler (deprecated)
+    /**
+     * The tcp pre init handler is called after the raw tcp connection has been
+     * established but before any additional wrappers (proxy connects, TLS
+     * handshakes, etc) have been performed.
+     *
+     * @deprecated Use set_tcp_pre_init_handler instead
+     *
+     * @param h The handler to call on tcp pre init.
+     */
+    void set_tcp_init_handler(tcp_init_handler h) {
+        set_tcp_pre_init_handler(h);
+    }
+
+    /// Sets the tcp post init handler
+    /**
+     * The tcp post init handler is called after the tcp connection has been
+     * established and all additional wrappers (proxy connects, TLS handshakes,
+     * etc have been performed. This is fired before any bytes are read or any
+     * WebSocket specific handshake logic has been performed.
+     *
+     * @since 0.3.0
+     *
+     * @param h The handler to call on tcp post init.
+     */
+    void set_tcp_post_init_handler(tcp_init_handler h) {
+        m_tcp_post_init_handler = h;
+    }
+
+    /// Sets the maximum length of the queue of pending connections.
+    /**
+     * Sets the maximum length of the queue of pending connections. Increasing
+     * this will allow WebSocket++ to queue additional incoming connections.
+     * Setting it higher may prevent failed connections at high connection rates
+     * but may cause additional latency.
+     *
+     * For this value to take effect you may need to adjust operating system
+     * settings.
+     *
+     * New values affect future calls to listen only.
+     *
+     * The default value is specified as *::asio::socket_base::max_connections
+     * which uses the operating system defined maximum queue length. Your OS
+     * may restrict or silently lower this value. A value of zero may cause
+     * all connections to be rejected.
+     *
+     * @since 0.3.0
+     *
+     * @param backlog The maximum length of the queue of pending connections
+     */
+    void set_listen_backlog(int backlog) {
+        m_listen_backlog = backlog;
+    }
+
+    /// Sets whether to use the SO_REUSEADDR flag when opening listening sockets
+    /**
+     * Specifies whether or not to use the SO_REUSEADDR TCP socket option. What
+     * this flag does depends on your operating system.
+     *
+     * Please consult operating system documentation for more details. There
+     * may be security consequences to enabling this option.
+     *
+     * New values affect future calls to listen only so set this value prior to
+     * calling listen.
+     *
+     * The default is false.
+     *
+     * @since 0.3.0
+     *
+     * @param value Whether or not to use the SO_REUSEADDR option
+     */
+    void set_reuse_addr(bool value) {
+        m_reuse_addr = value;
+    }
+
+    /// Retrieve a reference to the endpoint's io_service
+    /**
+     * The io_service may be an internal or external one. This may be used to
+     * call methods of the io_service that are not explicitly wrapped by the
+     * endpoint.
+     *
+     * This method is only valid after the endpoint has been initialized with
+     * `init_asio`. No error will be returned if it isn't.
+     *
+     * @return A reference to the endpoint's io_service
+     */
+    lib::asio::io_service & get_io_service() {
+        return *m_io_service;
+    }
+    
+    /// Get local TCP endpoint
+    /**
+     * Extracts the local endpoint from the acceptor. This represents the
+     * address that WebSocket++ is listening on.
+     *
+     * Sets a bad_descriptor error if the acceptor is not currently listening
+     * or otherwise unavailable.
+     * 
+     * @since 0.7.0
+     *
+     * @param ec Set to indicate what error occurred, if any.
+     * @return The local endpoint
+     */
+    lib::asio::ip::tcp::endpoint get_local_endpoint(lib::asio::error_code & ec) {
+        if (m_acceptor) {
+            return m_acceptor->local_endpoint(ec);
+        } else {
+            ec = lib::asio::error::make_error_code(lib::asio::error::bad_descriptor);
+            return lib::asio::ip::tcp::endpoint();
+        }
+    }
+
+    /// Set up endpoint for listening manually (exception free)
+    /**
+     * Bind the internal acceptor using the specified settings. The endpoint
+     * must have been initialized by calling init_asio before listening.
+     *
+     * @param ep An endpoint to read settings from
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    void listen(lib::asio::ip::tcp::endpoint const & ep, lib::error_code & ec)
+    {
+        if (m_state != READY) {
+            m_elog->write(log::elevel::library,
+                "asio::listen called from the wrong state");
+            using websocketpp::error::make_error_code;
+            ec = make_error_code(websocketpp::error::invalid_state);
+            return;
+        }
+
+        m_alog->write(log::alevel::devel,"asio::listen");
+
+        lib::asio::error_code bec;
+
+        m_acceptor->open(ep.protocol(),bec);
+        if (bec) {ec = clean_up_listen_after_error(bec);return;}
+        
+        m_acceptor->set_option(lib::asio::socket_base::reuse_address(m_reuse_addr),bec);
+        if (bec) {ec = clean_up_listen_after_error(bec);return;}
+        
+        // if a TCP pre-bind handler is present, run it
+        if (m_tcp_pre_bind_handler) {
+            ec = m_tcp_pre_bind_handler(m_acceptor);
+            if (ec) {
+                ec = clean_up_listen_after_error(ec);
+                return;
+            }
+        }
+        
+        m_acceptor->bind(ep,bec);
+        if (bec) {ec = clean_up_listen_after_error(bec);return;}
+        
+        m_acceptor->listen(m_listen_backlog,bec);
+        if (bec) {ec = clean_up_listen_after_error(bec);return;}
+        
+        // Success
+        m_state = LISTENING;
+        ec = lib::error_code();
+    }
+
+
+
+    /// Set up endpoint for listening manually
+    /**
+     * Bind the internal acceptor using the settings specified by the endpoint e
+     *
+     * @param ep An endpoint to read settings from
+     */
+    void listen(lib::asio::ip::tcp::endpoint const & ep) {
+        lib::error_code ec;
+        listen(ep,ec);
+        if (ec) { throw exception(ec); }
+    }
+
+    /// Set up endpoint for listening with protocol and port (exception free)
+    /**
+     * Bind the internal acceptor using the given internet protocol and port.
+     * The endpoint must have been initialized by calling init_asio before
+     * listening.
+     *
+     * Common options include:
+     * - IPv6 with mapped IPv4 for dual stack hosts lib::asio::ip::tcp::v6()
+     * - IPv4 only: lib::asio::ip::tcp::v4()
+     *
+     * @param internet_protocol The internet protocol to use.
+     * @param port The port to listen on.
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    template <typename InternetProtocol>
+    void listen(InternetProtocol const & internet_protocol, uint16_t port,
+        lib::error_code & ec)
+    {
+        lib::asio::ip::tcp::endpoint ep(internet_protocol, port);
+        listen(ep,ec);
+    }
+
+    /// Set up endpoint for listening with protocol and port
+    /**
+     * Bind the internal acceptor using the given internet protocol and port.
+     * The endpoint must have been initialized by calling init_asio before
+     * listening.
+     *
+     * Common options include:
+     * - IPv6 with mapped IPv4 for dual stack hosts lib::asio::ip::tcp::v6()
+     * - IPv4 only: lib::asio::ip::tcp::v4()
+     *
+     * @param internet_protocol The internet protocol to use.
+     * @param port The port to listen on.
+     */
+    template <typename InternetProtocol>
+    void listen(InternetProtocol const & internet_protocol, uint16_t port)
+    {
+        lib::asio::ip::tcp::endpoint ep(internet_protocol, port);
+        listen(ep);
+    }
+
+    /// Set up endpoint for listening on a port (exception free)
+    /**
+     * Bind the internal acceptor using the given port. The IPv6 protocol with
+     * mapped IPv4 for dual stack hosts will be used. If you need IPv4 only use
+     * the overload that allows specifying the protocol explicitly.
+     *
+     * The endpoint must have been initialized by calling init_asio before
+     * listening.
+     *
+     * @param port The port to listen on.
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    void listen(uint16_t port, lib::error_code & ec) {
+        listen(lib::asio::ip::tcp::v6(), port, ec);
+    }
+
+    /// Set up endpoint for listening on a port
+    /**
+     * Bind the internal acceptor using the given port. The IPv6 protocol with
+     * mapped IPv4 for dual stack hosts will be used. If you need IPv4 only use
+     * the overload that allows specifying the protocol explicitly.
+     *
+     * The endpoint must have been initialized by calling init_asio before
+     * listening.
+     *
+     * @param port The port to listen on.
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    void listen(uint16_t port) {
+        listen(lib::asio::ip::tcp::v6(), port);
+    }
+
+    /// Set up endpoint for listening on a host and service (exception free)
+    /**
+     * Bind the internal acceptor using the given host and service. More details
+     * about what host and service can be are available in the Asio
+     * documentation for ip::basic_resolver_query::basic_resolver_query's
+     * constructors.
+     *
+     * The endpoint must have been initialized by calling init_asio before
+     * listening.
+     *
+     * @param host A string identifying a location. May be a descriptive name or
+     * a numeric address string.
+     * @param service A string identifying the requested service. This may be a
+     * descriptive name or a numeric string corresponding to a port number.
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    void listen(std::string const & host, std::string const & service,
+        lib::error_code & ec)
+    {
+        using lib::asio::ip::tcp;
+        tcp::resolver r(*m_io_service);
+        tcp::resolver::query query(host, service);
+        tcp::resolver::iterator endpoint_iterator = r.resolve(query);
+        tcp::resolver::iterator end;
+        if (endpoint_iterator == end) {
+            m_elog->write(log::elevel::library,
+                "asio::listen could not resolve the supplied host or service");
+            ec = make_error_code(error::invalid_host_service);
+            return;
+        }
+        listen(*endpoint_iterator,ec);
+    }
+
+    /// Set up endpoint for listening on a host and service
+    /**
+     * Bind the internal acceptor using the given host and service. More details
+     * about what host and service can be are available in the Asio
+     * documentation for ip::basic_resolver_query::basic_resolver_query's
+     * constructors.
+     *
+     * The endpoint must have been initialized by calling init_asio before
+     * listening.
+     *
+     * @param host A string identifying a location. May be a descriptive name or
+     * a numeric address string.
+     * @param service A string identifying the requested service. This may be a
+     * descriptive name or a numeric string corresponding to a port number.
+     * @param ec Set to indicate what error occurred, if any.
+     */
+    void listen(std::string const & host, std::string const & service)
+    {
+        lib::error_code ec;
+        listen(host,service,ec);
+        if (ec) { throw exception(ec); }
+    }
+
+    /// Stop listening (exception free)
+    /**
+     * Stop listening and accepting new connections. This will not end any
+     * existing connections.
+     *
+     * @since 0.3.0-alpha4
+     * @param ec A status code indicating an error, if any.
+     */
+    void stop_listening(lib::error_code & ec) {
+        if (m_state != LISTENING) {
+            m_elog->write(log::elevel::library,
+                "asio::listen called from the wrong state");
+            using websocketpp::error::make_error_code;
+            ec = make_error_code(websocketpp::error::invalid_state);
+            return;
+        }
+
+        m_acceptor->close();
+        m_state = READY;
+        ec = lib::error_code();
+    }
+
+    /// Stop listening
+    /**
+     * Stop listening and accepting new connections. This will not end any
+     * existing connections.
+     *
+     * @since 0.3.0-alpha4
+     */
+    void stop_listening() {
+        lib::error_code ec;
+        stop_listening(ec);
+        if (ec) { throw exception(ec); }
+    }
+
+    /// Check if the endpoint is listening
+    /**
+     * @return Whether or not the endpoint is listening.
+     */
+    bool is_listening() const {
+        return (m_state == LISTENING);
+    }
+
+    /// wraps the run method of the internal io_service object
+    std::size_t run() {
+        return m_io_service->run();
+    }
+
+    /// wraps the run_one method of the internal io_service object
+    /**
+     * @since 0.3.0-alpha4
+     */
+    std::size_t run_one() {
+        return m_io_service->run_one();
+    }
+
+    /// wraps the stop method of the internal io_service object
+    void stop() {
+        m_io_service->stop();
+    }
+
+    /// wraps the poll method of the internal io_service object
+    std::size_t poll() {
+        return m_io_service->poll();
+    }
+
+    /// wraps the poll_one method of the internal io_service object
+    std::size_t poll_one() {
+        return m_io_service->poll_one();
+    }
+
+    /// wraps the reset method of the internal io_service object
+    void reset() {
+        m_io_service->reset();
+    }
+
+    /// wraps the stopped method of the internal io_service object
+    bool stopped() const {
+        return m_io_service->stopped();
+    }
+
+    /// Marks the endpoint as perpetual, stopping it from exiting when empty
+    /**
+     * Marks the endpoint as perpetual. Perpetual endpoints will not
+     * automatically exit when they run out of connections to process. To stop
+     * a perpetual endpoint call `end_perpetual`.
+     *
+     * An endpoint may be marked perpetual at any time by any thread. It must be
+     * called either before the endpoint has run out of work or before it was
+     * started
+     *
+     * @since 0.3.0
+     */
+    void start_perpetual() {
+        m_work = lib::make_shared<lib::asio::io_service::work>(
+            lib::ref(*m_io_service)
+        );
+    }
+
+    /// Clears the endpoint's perpetual flag, allowing it to exit when empty
+    /**
+     * Clears the endpoint's perpetual flag. This will cause the endpoint's run
+     * method to exit normally when it runs out of connections. If there are
+     * currently active connections it will not end until they are complete.
+     *
+     * @since 0.3.0
+     */
+    void stop_perpetual() {
+        m_work.reset();
+    }
+
+    /// Call back a function after a period of time.
+    /**
+     * Sets a timer that calls back a function after the specified period of
+     * milliseconds. Returns a handle that can be used to cancel the timer.
+     * A cancelled timer will return the error code error::operation_aborted
+     * A timer that expired will return no error.
+     *
+     * @param duration Length of time to wait in milliseconds
+     * @param callback The function to call back when the timer has expired
+     * @return A handle that can be used to cancel the timer if it is no longer
+     * needed.
+     */
+    timer_ptr set_timer(long duration, timer_handler callback) {
+        timer_ptr new_timer = lib::make_shared<lib::asio::steady_timer>(
+            *m_io_service,
+             lib::asio::milliseconds(duration)
+        );
+
+        new_timer->async_wait(
+            lib::bind(
+                &type::handle_timer,
+                this,
+                new_timer,
+                callback,
+                lib::placeholders::_1
+            )
+        );
+
+        return new_timer;
+    }
+
+    /// Timer handler
+    /**
+     * The timer pointer is included to ensure the timer isn't destroyed until
+     * after it has expired.
+     *
+     * @param t Pointer to the timer in question
+     * @param callback The function to call back
+     * @param ec A status code indicating an error, if any.
+     */
+    void handle_timer(timer_ptr, timer_handler callback,
+        lib::asio::error_code const & ec)
+    {
+        if (ec) {
+            if (ec == lib::asio::error::operation_aborted) {
+                callback(make_error_code(transport::error::operation_aborted));
+            } else {
+                m_elog->write(log::elevel::info,
+                    "asio handle_timer error: "+ec.message());
+                log_err(log::elevel::info,"asio handle_timer",ec);
+                callback(socket_con_type::translate_ec(ec));
+            }
+        } else {
+            callback(lib::error_code());
+        }
+    }
+
+    /// Accept the next connection attempt and assign it to con (exception free)
+    /**
+     * @param tcon The connection to accept into.
+     * @param callback The function to call when the operation is complete.
+     * @param ec A status code indicating an error, if any.
+     */
+    void async_accept(transport_con_ptr tcon, accept_handler callback,
+        lib::error_code & ec)
+    {
+        if (m_state != LISTENING || !m_acceptor) {
+            using websocketpp::error::make_error_code;
+            ec = make_error_code(websocketpp::error::async_accept_not_listening);
+            return;
+        }
+
+        m_alog->write(log::alevel::devel, "asio::async_accept");
+
+        if (config::enable_multithreading) {
+            m_acceptor->async_accept(
+                tcon->get_raw_socket(),
+                tcon->get_strand()->wrap(lib::bind(
+                    &type::handle_accept,
+                    this,
+                    callback,
+                    lib::placeholders::_1
+                ))
+            );
+        } else {
+            m_acceptor->async_accept(
+                tcon->get_raw_socket(),
+                lib::bind(
+                    &type::handle_accept,
+                    this,
+                    callback,
+                    lib::placeholders::_1
+                )
+            );
+        }
+    }
+
+    /// Accept the next connection attempt and assign it to con.
+    /**
+     * @param tcon The connection to accept into.
+     * @param callback The function to call when the operation is complete.
+     */
+    void async_accept(transport_con_ptr tcon, accept_handler callback) {
+        lib::error_code ec;
+        async_accept(tcon,callback,ec);
+        if (ec) { throw exception(ec); }
+    }
+protected:
+    /// Initialize logging
+    /**
+     * The loggers are located in the main endpoint class. As such, the
+     * transport doesn't have direct access to them. This method is called
+     * by the endpoint constructor to allow shared logging from the transport
+     * component. These are raw pointers to member variables of the endpoint.
+     * In particular, they cannot be used in the transport constructor as they
+     * haven't been constructed yet, and cannot be used in the transport
+     * destructor as they will have been destroyed by then.
+     */
+    void init_logging(const lib::shared_ptr<alog_type>& a, const lib::shared_ptr<elog_type>& e) {
+        m_alog = a;
+        m_elog = e;
+    }
+
+    void handle_accept(accept_handler callback, lib::asio::error_code const & 
+        asio_ec)
+    {
+        lib::error_code ret_ec;
+
+        m_alog->write(log::alevel::devel, "asio::handle_accept");
+
+        if (asio_ec) {
+            if (asio_ec == lib::asio::errc::operation_canceled) {
+                ret_ec = make_error_code(websocketpp::error::operation_canceled);
+            } else {
+                log_err(log::elevel::info,"asio handle_accept",asio_ec);
+                ret_ec = socket_con_type::translate_ec(asio_ec);
+            }
+        }
+
+        callback(ret_ec);
+    }
+
+    /// Initiate a new connection
+    // TODO: there have to be some more failure conditions here
+    void async_connect(transport_con_ptr tcon, uri_ptr u, connect_handler cb) {
+        using namespace lib::asio::ip;
+
+        // Create a resolver
+        if (!m_resolver) {
+            m_resolver = lib::make_shared<lib::asio::ip::tcp::resolver>(
+                lib::ref(*m_io_service));
+        }
+
+        tcon->set_uri(u);
+
+        std::string proxy = tcon->get_proxy();
+        std::string host;
+        std::string port;
+
+        if (proxy.empty()) {
+            host = u->get_host();
+            port = u->get_port_str();
+        } else {
+            lib::error_code ec;
+
+            uri_ptr pu = lib::make_shared<uri>(proxy);
+
+            if (!pu->get_valid()) {
+                cb(make_error_code(error::proxy_invalid));
+                return;
+            }
+
+            ec = tcon->proxy_init(u->get_authority());
+            if (ec) {
+                cb(ec);
+                return;
+            }
+
+            host = pu->get_host();
+            port = pu->get_port_str();
+        }
+
+        tcp::resolver::query query(host,port);
+
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,
+                "starting async DNS resolve for "+host+":"+port);
+        }
+
+        timer_ptr dns_timer;
+
+        dns_timer = tcon->set_timer(
+            config::timeout_dns_resolve,
+            lib::bind(
+                &type::handle_resolve_timeout,
+                this,
+                dns_timer,
+                cb,
+                lib::placeholders::_1
+            )
+        );
+
+        if (config::enable_multithreading) {
+            m_resolver->async_resolve(
+                query,
+                tcon->get_strand()->wrap(lib::bind(
+                    &type::handle_resolve,
+                    this,
+                    tcon,
+                    dns_timer,
+                    cb,
+                    lib::placeholders::_1,
+                    lib::placeholders::_2
+                ))
+            );
+        } else {
+            m_resolver->async_resolve(
+                query,
+                lib::bind(
+                    &type::handle_resolve,
+                    this,
+                    tcon,
+                    dns_timer,
+                    cb,
+                    lib::placeholders::_1,
+                    lib::placeholders::_2
+                )
+            );
+        }
+    }
+
+    /// DNS resolution timeout handler
+    /**
+     * The timer pointer is included to ensure the timer isn't destroyed until
+     * after it has expired.
+     *
+     * @param dns_timer Pointer to the timer in question
+     * @param callback The function to call back
+     * @param ec A status code indicating an error, if any.
+     */
+    void handle_resolve_timeout(timer_ptr, connect_handler callback,
+        lib::error_code const & ec)
+    {
+        lib::error_code ret_ec;
+
+        if (ec) {
+            if (ec == transport::error::operation_aborted) {
+                m_alog->write(log::alevel::devel,
+                    "asio handle_resolve_timeout timer cancelled");
+                return;
+            }
+
+            log_err(log::elevel::devel,"asio handle_resolve_timeout",ec);
+            ret_ec = ec;
+        } else {
+            ret_ec = make_error_code(transport::error::timeout);
+        }
+
+        m_alog->write(log::alevel::devel,"DNS resolution timed out");
+        m_resolver->cancel();
+        callback(ret_ec);
+    }
+
+    void handle_resolve(transport_con_ptr tcon, timer_ptr dns_timer,
+        connect_handler callback, lib::asio::error_code const & ec,
+        lib::asio::ip::tcp::resolver::iterator iterator)
+    {
+        if (ec == lib::asio::error::operation_aborted ||
+            lib::asio::is_neg(dns_timer->expires_from_now()))
+        {
+            m_alog->write(log::alevel::devel,"async_resolve cancelled");
+            return;
+        }
+
+        dns_timer->cancel();
+
+        if (ec) {
+            log_err(log::elevel::info,"asio async_resolve",ec);
+            callback(socket_con_type::translate_ec(ec));
+            return;
+        }
+
+        if (m_alog->static_test(log::alevel::devel)) {
+            std::stringstream s;
+            s << "Async DNS resolve successful. Results: ";
+
+            lib::asio::ip::tcp::resolver::iterator it, end;
+            for (it = iterator; it != end; ++it) {
+                s << (*it).endpoint() << " ";
+            }
+
+            m_alog->write(log::alevel::devel,s.str());
+        }
+
+        m_alog->write(log::alevel::devel,"Starting async connect");
+
+        timer_ptr con_timer;
+
+        con_timer = tcon->set_timer(
+            config::timeout_connect,
+            lib::bind(
+                &type::handle_connect_timeout,
+                this,
+                tcon,
+                con_timer,
+                callback,
+                lib::placeholders::_1
+            )
+        );
+
+        if (config::enable_multithreading) {
+            lib::asio::async_connect(
+                tcon->get_raw_socket(),
+                iterator,
+                tcon->get_strand()->wrap(lib::bind(
+                    &type::handle_connect,
+                    this,
+                    tcon,
+                    con_timer,
+                    callback,
+                    lib::placeholders::_1
+                ))
+            );
+        } else {
+            lib::asio::async_connect(
+                tcon->get_raw_socket(),
+                iterator,
+                lib::bind(
+                    &type::handle_connect,
+                    this,
+                    tcon,
+                    con_timer,
+                    callback,
+                    lib::placeholders::_1
+                )
+            );
+        }
+    }
+
+    /// Asio connect timeout handler
+    /**
+     * The timer pointer is included to ensure the timer isn't destroyed until
+     * after it has expired.
+     *
+     * @param tcon Pointer to the transport connection that is being connected
+     * @param con_timer Pointer to the timer in question
+     * @param callback The function to call back
+     * @param ec A status code indicating an error, if any.
+     */
+    void handle_connect_timeout(transport_con_ptr tcon, timer_ptr,
+        connect_handler callback, lib::error_code const & ec)
+    {
+        lib::error_code ret_ec;
+
+        if (ec) {
+            if (ec == transport::error::operation_aborted) {
+                m_alog->write(log::alevel::devel,
+                    "asio handle_connect_timeout timer cancelled");
+                return;
+            }
+
+            log_err(log::elevel::devel,"asio handle_connect_timeout",ec);
+            ret_ec = ec;
+        } else {
+            ret_ec = make_error_code(transport::error::timeout);
+        }
+
+        m_alog->write(log::alevel::devel,"TCP connect timed out");
+        tcon->cancel_socket_checked();
+        callback(ret_ec);
+    }
+
+    void handle_connect(transport_con_ptr tcon, timer_ptr con_timer,
+        connect_handler callback, lib::asio::error_code const & ec)
+    {
+        if (ec == lib::asio::error::operation_aborted ||
+            lib::asio::is_neg(con_timer->expires_from_now()))
+        {
+            m_alog->write(log::alevel::devel,"async_connect cancelled");
+            return;
+        }
+
+        con_timer->cancel();
+
+        if (ec) {
+            log_err(log::elevel::info,"asio async_connect",ec);
+            callback(socket_con_type::translate_ec(ec));
+            return;
+        }
+
+        if (m_alog->static_test(log::alevel::devel)) {
+            m_alog->write(log::alevel::devel,
+                "Async connect to "+tcon->get_remote_endpoint()+" successful.");
+        }
+
+        callback(lib::error_code());
+    }
+
+    /// Initialize a connection
+    /**
+     * init is called by an endpoint once for each newly created connection.
+     * It's purpose is to give the transport policy the chance to perform any
+     * transport specific initialization that couldn't be done via the default
+     * constructor.
+     *
+     * @param tcon A pointer to the transport portion of the connection.
+     *
+     * @return A status code indicating the success or failure of the operation
+     */
+    lib::error_code init(transport_con_ptr tcon) {
+        m_alog->write(log::alevel::devel, "transport::asio::init");
+
+        // Initialize the connection socket component
+        socket_type::init(lib::static_pointer_cast<socket_con_type,
+            transport_con_type>(tcon));
+
+        lib::error_code ec;
+
+        ec = tcon->init_asio(m_io_service);
+        if (ec) {return ec;}
+
+        tcon->set_tcp_pre_init_handler(m_tcp_pre_init_handler);
+        tcon->set_tcp_post_init_handler(m_tcp_post_init_handler);
+
+        return lib::error_code();
+    }
+private:
+    /// Convenience method for logging the code and message for an error_code
+    template <typename error_type>
+    void log_err(log::level l, char const * msg, error_type const & ec) {
+        std::stringstream s;
+        s << msg << " error: " << ec << " (" << ec.message() << ")";
+        m_elog->write(l,s.str());
+    }
+
+    /// Helper for cleaning up in the listen method after an error
+    template <typename error_type>
+    lib::error_code clean_up_listen_after_error(error_type const & ec) {
+        if (m_acceptor->is_open()) {
+            m_acceptor->close();
+        }
+        log_err(log::elevel::info,"asio listen",ec);
+        return socket_con_type::translate_ec(ec);
+    }
+
+    enum state {
+        UNINITIALIZED = 0,
+        READY = 1,
+        LISTENING = 2
+    };
+
+    // Handlers
+    tcp_pre_bind_handler    m_tcp_pre_bind_handler;
+    tcp_init_handler    m_tcp_pre_init_handler;
+    tcp_init_handler    m_tcp_post_init_handler;
+
+    // Network Resources
+    io_service_ptr      m_io_service;
+    bool                m_external_io_service;
+    acceptor_ptr        m_acceptor;
+    resolver_ptr        m_resolver;
+    work_ptr            m_work;
+
+    // Network constants
+    int                 m_listen_backlog;
+    bool                m_reuse_addr;
+
+    lib::shared_ptr<elog_type> m_elog;
+    lib::shared_ptr<alog_type> m_alog;
+
+    // Transport state
+    state               m_state;
+};
+
+} // namespace asio
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_ASIO_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/asio/security/base.hpp b/subprojects/websocketpp/websocketpp/transport/asio/security/base.hpp
new file mode 100644
index 000000000..0f08f4046
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/asio/security/base.hpp
@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_ASIO_SOCKET_BASE_HPP
+#define WEBSOCKETPP_TRANSPORT_ASIO_SOCKET_BASE_HPP
+
+#include <websocketpp/common/asio.hpp>
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/common/functional.hpp>
+#include <websocketpp/common/system_error.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/connection_hdl.hpp>
+
+#include <string>
+
+// Interface that sockets/security policies must implement
+
+/*
+ * Endpoint Interface
+ *
+ * bool is_secure() const;
+ * @return Whether or not the endpoint creates secure connections
+ *
+ * lib::error_code init(socket_con_ptr scon);
+ * Called by the transport after a new connection is created to initialize
+ * the socket component of the connection.
+ * @param scon Pointer to the socket component of the connection
+ * @return Error code (empty on success)
+ */
+
+
+// Connection
+// TODO
+// set_hostname(std::string hostname)
+// pre_init(init_handler);
+// post_init(init_handler);
+
+namespace websocketpp {
+namespace transport {
+namespace asio {
+namespace socket {
+
+typedef lib::function<void(lib::asio::error_code const &)> shutdown_handler;
+
+/**
+ * The transport::asio::socket::* classes are a set of security/socket related
+ * policies and support code for the ASIO transport types.
+ */
+
+/// Errors related to asio transport sockets
+namespace error {
+    enum value {
+        /// Catch-all error for security policy errors that don't fit in other
+        /// categories
+        security = 1,
+
+        /// Catch-all error for socket component errors that don't fit in other
+        /// categories
+        socket,
+
+        /// A function was called in a state that it was illegal to do so.
+        invalid_state,
+
+        /// The application was prompted to provide a TLS context and it was
+        /// empty or otherwise invalid
+        invalid_tls_context,
+
+        /// TLS Handshake Timeout
+        tls_handshake_timeout,
+
+        /// pass_through from underlying library
+        pass_through,
+
+        /// Required tls_init handler not present
+        missing_tls_init_handler,
+
+        /// TLS Handshake Failed
+        tls_handshake_failed,
+        
+        /// Failed to set TLS SNI hostname
+        tls_failed_sni_hostname
+    };
+} // namespace error
+
+/// Error category related to asio transport socket policies
+class socket_category : public lib::error_category {
+public:
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.transport.asio.socket";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case error::security:
+                return "Security policy error";
+            case error::socket:
+                return "Socket component error";
+            case error::invalid_state:
+                return "Invalid state";
+            case error::invalid_tls_context:
+                return "Invalid or empty TLS context supplied";
+            case error::tls_handshake_timeout:
+                return "TLS handshake timed out";
+            case error::pass_through:
+                return "Pass through from socket policy";
+            case error::missing_tls_init_handler:
+                return "Required tls_init handler not present.";
+            case error::tls_handshake_failed:
+                return "TLS handshake failed";
+            case error::tls_failed_sni_hostname:
+                return "Failed to set TLS SNI hostname";
+            default:
+                return "Unknown";
+        }
+    }
+};
+
+inline lib::error_category const & get_socket_category() {
+    static socket_category instance;
+    return instance;
+}
+
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_socket_category());
+}
+
+/// Type of asio transport socket policy initialization handlers
+typedef lib::function<void(const lib::error_code&)> init_handler;
+
+} // namespace socket
+} // namespace asio
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_ASIO_SOCKET_BASE_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/asio/security/none.hpp b/subprojects/websocketpp/websocketpp/transport/asio/security/none.hpp
new file mode 100644
index 000000000..5c8293dbe
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/asio/security/none.hpp
@@ -0,0 +1,373 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_SECURITY_NONE_HPP
+#define WEBSOCKETPP_TRANSPORT_SECURITY_NONE_HPP
+
+#include <websocketpp/uri.hpp>
+
+#include <websocketpp/transport/base/connection.hpp>
+#include <websocketpp/transport/asio/security/base.hpp>
+
+#include <websocketpp/common/asio.hpp>
+#include <websocketpp/common/memory.hpp>
+
+#include <sstream>
+#include <string>
+
+namespace websocketpp {
+namespace transport {
+namespace asio {
+/// A socket policy for the asio transport that implements a plain, unencrypted
+/// socket
+namespace basic_socket {
+
+/// The signature of the socket init handler for this socket policy
+typedef lib::function<void(connection_hdl,lib::asio::ip::tcp::socket&)>
+    socket_init_handler;
+
+/// Basic Asio connection socket component
+/**
+ * transport::asio::basic_socket::connection implements a connection socket
+ * component using Asio ip::tcp::socket.
+ */
+class connection : public lib::enable_shared_from_this<connection> {
+public:
+    /// Type of this connection socket component
+    typedef connection type;
+    /// Type of a shared pointer to this connection socket component
+    typedef lib::shared_ptr<type> ptr;
+
+    /// Type of a pointer to the Asio io_service being used
+    typedef lib::asio::io_service* io_service_ptr;
+    /// Type of a pointer to the Asio io_service strand being used
+    typedef lib::shared_ptr<lib::asio::io_service::strand> strand_ptr;
+    /// Type of the ASIO socket being used
+    typedef lib::asio::ip::tcp::socket socket_type;
+    /// Type of a shared pointer to the socket being used.
+    typedef lib::shared_ptr<socket_type> socket_ptr;
+
+    explicit connection() : m_state(UNINITIALIZED) {
+        //std::cout << "transport::asio::basic_socket::connection constructor"
+        //          << std::endl;
+    }
+
+    /// Get a shared pointer to this component
+    ptr get_shared() {
+        return shared_from_this();
+    }
+
+    /// Check whether or not this connection is secure
+    /**
+     * @return Whether or not this connection is secure
+     */
+    bool is_secure() const {
+        return false;
+    }
+
+    /// Set the socket initialization handler
+    /**
+     * The socket initialization handler is called after the socket object is
+     * created but before it is used. This gives the application a chance to
+     * set any Asio socket options it needs.
+     *
+     * @param h The new socket_init_handler
+     */
+    void set_socket_init_handler(socket_init_handler h) {
+        m_socket_init_handler = h;
+    }
+
+    /// Retrieve a pointer to the underlying socket
+    /**
+     * This is used internally. It can also be used to set socket options, etc
+     */
+    lib::asio::ip::tcp::socket & get_socket() {
+        return *m_socket;
+    }
+
+    /// Retrieve a pointer to the underlying socket
+    /**
+     * This is used internally.
+     */
+    lib::asio::ip::tcp::socket & get_next_layer() {
+        return *m_socket;
+    }
+
+    /// Retrieve a pointer to the underlying socket
+    /**
+     * This is used internally. It can also be used to set socket options, etc
+     */
+    lib::asio::ip::tcp::socket & get_raw_socket() {
+        return *m_socket;
+    }
+
+    /// Get the remote endpoint address
+    /**
+     * The iostream transport has no information about the ultimate remote
+     * endpoint. It will return the string "iostream transport". To indicate
+     * this.
+     *
+     * TODO: allow user settable remote endpoint addresses if this seems useful
+     *
+     * @return A string identifying the address of the remote endpoint
+     */
+    std::string get_remote_endpoint(lib::error_code & ec) const {
+        std::stringstream s;
+
+        lib::asio::error_code aec;
+        lib::asio::ip::tcp::endpoint ep = m_socket->remote_endpoint(aec);
+
+        if (aec) {
+            ec = error::make_error_code(error::pass_through);
+            s << "Error getting remote endpoint: " << aec
+               << " (" << aec.message() << ")";
+            return s.str();
+        } else {
+            ec = lib::error_code();
+            s << ep;
+            return s.str();
+        }
+    }
+protected:
+    /// Perform one time initializations
+    /**
+     * init_asio is called once immediately after construction to initialize
+     * Asio components to the io_service
+     *
+     * @param service A pointer to the endpoint's io_service
+     * @param strand A shared pointer to the connection's asio strand
+     * @param is_server Whether or not the endpoint is a server or not.
+     */
+    lib::error_code init_asio (io_service_ptr service, strand_ptr, bool)
+    {
+        if (m_state != UNINITIALIZED) {
+            return socket::make_error_code(socket::error::invalid_state);
+        }
+
+        m_socket = lib::make_shared<lib::asio::ip::tcp::socket>(
+            lib::ref(*service));
+
+        if (m_socket_init_handler) {
+            m_socket_init_handler(m_hdl, *m_socket);
+        }
+
+        m_state = READY;
+
+        return lib::error_code();
+    }
+
+    /// Set uri hook
+    /**
+     * Called by the transport as a connection is being established to provide
+     * the uri being connected to to the security/socket layer.
+     *
+     * This socket policy doesn't use the uri so it is ignored.
+     *
+     * @since 0.6.0
+     *
+     * @param u The uri to set
+     */
+    void set_uri(uri_ptr) {}
+
+    /// Pre-initialize security policy
+    /**
+     * Called by the transport after a new connection is created to initialize
+     * the socket component of the connection. This method is not allowed to
+     * write any bytes to the wire. This initialization happens before any
+     * proxies or other intermediate wrappers are negotiated.
+     *
+     * @param callback Handler to call back with completion information
+     */
+    void pre_init(init_handler callback) {
+        if (m_state != READY) {
+            callback(socket::make_error_code(socket::error::invalid_state));
+            return;
+        }
+
+        m_state = READING;
+
+        callback(lib::error_code());
+    }
+
+    /// Post-initialize security policy
+    /**
+     * Called by the transport after all intermediate proxies have been
+     * negotiated. This gives the security policy the chance to talk with the
+     * real remote endpoint for a bit before the websocket handshake.
+     *
+     * @param callback Handler to call back with completion information
+     */
+    void post_init(init_handler callback) {
+        callback(lib::error_code());
+    }
+
+    /// Sets the connection handle
+    /**
+     * The connection handle is passed to any handlers to identify the
+     * connection
+     *
+     * @param hdl The new handle
+     */
+    void set_handle(connection_hdl hdl) {
+        m_hdl = hdl;
+    }
+
+    /// Cancel all async operations on this socket
+    /**
+     * Attempts to cancel all async operations on this socket and reports any
+     * failures.
+     *
+     * NOTE: Windows XP and earlier do not support socket cancellation.
+     *
+     * @return The error that occurred, if any.
+     */
+    lib::asio::error_code cancel_socket() {
+        lib::asio::error_code ec;
+        m_socket->cancel(ec);
+        return ec;
+    }
+
+    void async_shutdown(socket::shutdown_handler h) {
+        lib::asio::error_code ec;
+        m_socket->shutdown(lib::asio::ip::tcp::socket::shutdown_both, ec);
+        h(ec);
+    }
+
+    lib::error_code get_ec() const {
+        return lib::error_code();
+    }
+
+public:
+    /// Translate any security policy specific information about an error code
+    /**
+     * Translate_ec takes an Asio error code and attempts to convert its value 
+     * to an appropriate websocketpp error code. In the case that the Asio and
+     * Websocketpp error types are the same (such as using boost::asio and
+     * boost::system_error or using standalone asio and std::system_error the
+     * code will be passed through natively.
+     *
+     * In the case of a mismatch (boost::asio with std::system_error) a
+     * translated code will be returned. The plain socket policy does not have 
+     * any additional information so all such errors will be reported as the
+     * generic transport pass_through error.
+     *
+     * @since 0.3.0
+     *
+     * @param ec The error code to translate_ec
+     * @return The translated error code
+     */
+    template <typename ErrorCodeType>
+    static
+    lib::error_code translate_ec(ErrorCodeType) {
+        // We don't know any more information about this error so pass through
+        return make_error_code(transport::error::pass_through);
+    }
+
+    static
+    /// Overload of translate_ec to catch cases where lib::error_code is the 
+    /// same type as lib::asio::error_code
+    lib::error_code translate_ec(lib::error_code ec) {
+        // We don't know any more information about this error, but the error is
+        // the same type as the one we are translating to, so pass through
+        // untranslated.
+        return ec;
+    }
+private:
+    enum state {
+        UNINITIALIZED = 0,
+        READY = 1,
+        READING = 2
+    };
+
+    socket_ptr          m_socket;
+    state               m_state;
+
+    connection_hdl      m_hdl;
+    socket_init_handler m_socket_init_handler;
+};
+
+/// Basic ASIO endpoint socket component
+/**
+ * transport::asio::basic_socket::endpoint implements an endpoint socket
+ * component that uses Boost ASIO's ip::tcp::socket.
+ */
+class endpoint {
+public:
+    /// The type of this endpoint socket component
+    typedef endpoint type;
+
+    /// The type of the corresponding connection socket component
+    typedef connection socket_con_type;
+    /// The type of a shared pointer to the corresponding connection socket
+    /// component.
+    typedef socket_con_type::ptr socket_con_ptr;
+
+    explicit endpoint() {}
+
+    /// Checks whether the endpoint creates secure connections
+    /**
+     * @return Whether or not the endpoint creates secure connections
+     */
+    bool is_secure() const {
+        return false;
+    }
+
+    /// Set socket init handler
+    /**
+     * The socket init handler is called after a connection's socket is created
+     * but before it is used. This gives the end application an opportunity to
+     * set asio socket specific parameters.
+     *
+     * @param h The new socket_init_handler
+     */
+    void set_socket_init_handler(socket_init_handler h) {
+        m_socket_init_handler = h;
+    }
+protected:
+    /// Initialize a connection
+    /**
+     * Called by the transport after a new connection is created to initialize
+     * the socket component of the connection.
+     *
+     * @param scon Pointer to the socket component of the connection
+     *
+     * @return Error code (empty on success)
+     */
+    lib::error_code init(socket_con_ptr scon) {
+        scon->set_socket_init_handler(m_socket_init_handler);
+        return lib::error_code();
+    }
+private:
+    socket_init_handler m_socket_init_handler;
+};
+
+} // namespace basic_socket
+} // namespace asio
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_SECURITY_NONE_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/asio/security/tls.hpp b/subprojects/websocketpp/websocketpp/transport/asio/security/tls.hpp
new file mode 100644
index 000000000..c76fd9aa1
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/asio/security/tls.hpp
@@ -0,0 +1,475 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_SECURITY_TLS_HPP
+#define WEBSOCKETPP_TRANSPORT_SECURITY_TLS_HPP
+
+#include <websocketpp/transport/asio/security/base.hpp>
+
+#include <websocketpp/uri.hpp>
+
+#include <websocketpp/common/asio_ssl.hpp>
+#include <websocketpp/common/asio.hpp>
+#include <websocketpp/common/connection_hdl.hpp>
+#include <websocketpp/common/functional.hpp>
+#include <websocketpp/common/memory.hpp>
+
+#include <sstream>
+#include <string>
+
+namespace websocketpp {
+namespace transport {
+namespace asio {
+/// A socket policy for the asio transport that implements a TLS encrypted
+/// socket by wrapping with an asio::ssl::stream
+namespace tls_socket {
+
+/// The signature of the socket_init_handler for this socket policy
+typedef lib::function<void(connection_hdl,lib::asio::ssl::stream<
+    lib::asio::ip::tcp::socket>&)> socket_init_handler;
+/// The signature of the tls_init_handler for this socket policy
+typedef lib::function<lib::shared_ptr<lib::asio::ssl::context>(connection_hdl)>
+    tls_init_handler;
+
+/// TLS enabled Asio connection socket component
+/**
+ * transport::asio::tls_socket::connection implements a secure connection socket
+ * component that uses Asio's ssl::stream to wrap an ip::tcp::socket.
+ */
+class connection : public lib::enable_shared_from_this<connection> {
+public:
+    /// Type of this connection socket component
+    typedef connection type;
+    /// Type of a shared pointer to this connection socket component
+    typedef lib::shared_ptr<type> ptr;
+
+    /// Type of the ASIO socket being used
+    typedef lib::asio::ssl::stream<lib::asio::ip::tcp::socket> socket_type;
+    /// Type of a shared pointer to the ASIO socket being used
+    typedef lib::shared_ptr<socket_type> socket_ptr;
+    /// Type of a pointer to the ASIO io_service being used
+    typedef lib::asio::io_service * io_service_ptr;
+    /// Type of a pointer to the ASIO io_service strand being used
+    typedef lib::shared_ptr<lib::asio::io_service::strand> strand_ptr;
+    /// Type of a shared pointer to the ASIO TLS context being used
+    typedef lib::shared_ptr<lib::asio::ssl::context> context_ptr;
+
+    explicit connection() {
+        //std::cout << "transport::asio::tls_socket::connection constructor"
+        //          << std::endl;
+    }
+
+    /// Get a shared pointer to this component
+    ptr get_shared() {
+        return shared_from_this();
+    }
+
+    /// Check whether or not this connection is secure
+    /**
+     * @return Whether or not this connection is secure
+     */
+    bool is_secure() const {
+        return true;
+    }
+
+    /// Retrieve a pointer to the underlying socket
+    /**
+     * This is used internally. It can also be used to set socket options, etc
+     */
+    socket_type::lowest_layer_type & get_raw_socket() {
+        return m_socket->lowest_layer();
+    }
+
+    /// Retrieve a pointer to the layer below the ssl stream
+    /**
+     * This is used internally.
+     */
+    socket_type::next_layer_type & get_next_layer() {
+        return m_socket->next_layer();
+    }
+
+    /// Retrieve a pointer to the wrapped socket
+    /**
+     * This is used internally.
+     */
+    socket_type & get_socket() {
+        return *m_socket;
+    }
+
+    /// Set the socket initialization handler
+    /**
+     * The socket initialization handler is called after the socket object is
+     * created but before it is used. This gives the application a chance to
+     * set any ASIO socket options it needs.
+     *
+     * @param h The new socket_init_handler
+     */
+    void set_socket_init_handler(socket_init_handler h) {
+        m_socket_init_handler = h;
+    }
+
+    /// Set TLS init handler
+    /**
+     * The tls init handler is called when needed to request a TLS context for
+     * the library to use. A TLS init handler must be set and it must return a
+     * valid TLS context in order for this endpoint to be able to initialize
+     * TLS connections
+     *
+     * @param h The new tls_init_handler
+     */
+    void set_tls_init_handler(tls_init_handler h) {
+        m_tls_init_handler = h;
+    }
+
+    /// Get the remote endpoint address
+    /**
+     * The iostream transport has no information about the ultimate remote
+     * endpoint. It will return the string "iostream transport". To indicate
+     * this.
+     *
+     * TODO: allow user settable remote endpoint addresses if this seems useful
+     *
+     * @return A string identifying the address of the remote endpoint
+     */
+    std::string get_remote_endpoint(lib::error_code & ec) const {
+        std::stringstream s;
+
+        lib::asio::error_code aec;
+        lib::asio::ip::tcp::endpoint ep = m_socket->lowest_layer().remote_endpoint(aec);
+
+        if (aec) {
+            ec = error::make_error_code(error::pass_through);
+            s << "Error getting remote endpoint: " << aec
+               << " (" << aec.message() << ")";
+            return s.str();
+        } else {
+            ec = lib::error_code();
+            s << ep;
+            return s.str();
+        }
+    }
+protected:
+    /// Perform one time initializations
+    /**
+     * init_asio is called once immediately after construction to initialize
+     * Asio components to the io_service
+     *
+     * @param service A pointer to the endpoint's io_service
+     * @param strand A pointer to the connection's strand
+     * @param is_server Whether or not the endpoint is a server or not.
+     */
+    lib::error_code init_asio (io_service_ptr service, strand_ptr strand,
+        bool is_server)
+    {
+        if (!m_tls_init_handler) {
+            return socket::make_error_code(socket::error::missing_tls_init_handler);
+        }
+        m_context = m_tls_init_handler(m_hdl);
+
+        if (!m_context) {
+            return socket::make_error_code(socket::error::invalid_tls_context);
+        }
+        m_socket = lib::make_shared<socket_type>(
+            _WEBSOCKETPP_REF(*service),lib::ref(*m_context));
+
+        if (m_socket_init_handler) {
+            m_socket_init_handler(m_hdl, get_socket());
+        }
+
+        m_io_service = service;
+        m_strand = strand;
+        m_is_server = is_server;
+
+        return lib::error_code();
+    }
+
+    /// Set hostname hook
+    /**
+     * Called by the transport as a connection is being established to provide
+     * the hostname being connected to to the security/socket layer.
+     *
+     * This socket policy uses the hostname to set the appropriate TLS SNI
+     * header.
+     *
+     * @since 0.6.0
+     *
+     * @param u The uri to set
+     */
+    void set_uri(uri_ptr u) {
+        m_uri = u;
+    }
+
+    /// Pre-initialize security policy
+    /**
+     * Called by the transport after a new connection is created to initialize
+     * the socket component of the connection. This method is not allowed to
+     * write any bytes to the wire. This initialization happens before any
+     * proxies or other intermediate wrappers are negotiated.
+     *
+     * @param callback Handler to call back with completion information
+     */
+    void pre_init(init_handler callback) {
+        // TODO: is this the best way to check whether this function is 
+        //       available in the version of OpenSSL being used?
+        // TODO: consider case where host is an IP address
+#if OPENSSL_VERSION_NUMBER >= 0x90812f
+        if (!m_is_server) {
+            // For clients on systems with a suitable OpenSSL version, set the
+            // TLS SNI hostname header so connecting to TLS servers using SNI
+            // will work.
+            long res = SSL_set_tlsext_host_name(
+                get_socket().native_handle(), m_uri->get_host().c_str());
+            if (!(1 == res)) {
+                callback(socket::make_error_code(socket::error::tls_failed_sni_hostname));
+            }
+        }
+#endif
+
+        callback(lib::error_code());
+    }
+
+    /// Post-initialize security policy
+    /**
+     * Called by the transport after all intermediate proxies have been
+     * negotiated. This gives the security policy the chance to talk with the
+     * real remote endpoint for a bit before the websocket handshake.
+     *
+     * @param callback Handler to call back with completion information
+     */
+    void post_init(init_handler callback) {
+        m_ec = socket::make_error_code(socket::error::tls_handshake_timeout);
+
+        // TLS handshake
+        if (m_strand) {
+            m_socket->async_handshake(
+                get_handshake_type(),
+                m_strand->wrap(lib::bind(
+                    &type::handle_init, get_shared(),
+                    callback,
+                    lib::placeholders::_1
+                ))
+            );
+        } else {
+            m_socket->async_handshake(
+                get_handshake_type(),
+                lib::bind(
+                    &type::handle_init, get_shared(),
+                    callback,
+                    lib::placeholders::_1
+                )
+            );
+        }
+    }
+
+    /// Sets the connection handle
+    /**
+     * The connection handle is passed to any handlers to identify the
+     * connection
+     *
+     * @param hdl The new handle
+     */
+    void set_handle(connection_hdl hdl) {
+        m_hdl = hdl;
+    }
+
+    void handle_init(init_handler callback,lib::asio::error_code const & ec) {
+        if (ec) {
+            m_ec = socket::make_error_code(socket::error::tls_handshake_failed);
+        } else {
+            m_ec = lib::error_code();
+        }
+
+        callback(m_ec);
+    }
+
+    lib::error_code get_ec() const {
+        return m_ec;
+    }
+
+    /// Cancel all async operations on this socket
+    /**
+     * Attempts to cancel all async operations on this socket and reports any
+     * failures.
+     *
+     * NOTE: Windows XP and earlier do not support socket cancellation.
+     *
+     * @return The error that occurred, if any.
+     */
+    lib::asio::error_code cancel_socket() {
+        lib::asio::error_code ec;
+        get_raw_socket().cancel(ec);
+        return ec;
+    }
+
+    void async_shutdown(socket::shutdown_handler callback) {
+        if (m_strand) {
+            m_socket->async_shutdown(m_strand->wrap(callback));
+        } else {
+            m_socket->async_shutdown(callback);
+        }
+    }
+
+public:
+    /// Translate any security policy specific information about an error code
+    /**
+     * Translate_ec takes an Asio error code and attempts to convert its value
+     * to an appropriate websocketpp error code. In the case that the Asio and
+     * Websocketpp error types are the same (such as using boost::asio and
+     * boost::system_error or using standalone asio and std::system_error the
+     * code will be passed through natively.
+     *
+     * In the case of a mismatch (boost::asio with std::system_error) a
+     * translated code will be returned. Any error that is determined to be
+     * related to TLS but does not have a more specific websocketpp error code
+     * is returned under the catch all error `tls_error`. Non-TLS related errors
+     * are returned as the transport generic error `pass_through`
+     *
+     * @since 0.3.0
+     *
+     * @param ec The error code to translate_ec
+     * @return The translated error code
+     */
+    template <typename ErrorCodeType>
+    static
+    lib::error_code translate_ec(ErrorCodeType ec) {
+        if (ec.category() == lib::asio::error::get_ssl_category()) {
+            // We know it is a TLS related error, but otherwise don't know more.
+            // Pass through as TLS generic.
+            return make_error_code(transport::error::tls_error);
+        } else {
+            // We don't know any more information about this error so pass
+            // through
+            return make_error_code(transport::error::pass_through);
+        }
+    }
+
+    static
+    /// Overload of translate_ec to catch cases where lib::error_code is the
+    /// same type as lib::asio::error_code
+    lib::error_code translate_ec(lib::error_code ec) {
+        return ec;
+    }
+private:
+    socket_type::handshake_type get_handshake_type() {
+        if (m_is_server) {
+            return lib::asio::ssl::stream_base::server;
+        } else {
+            return lib::asio::ssl::stream_base::client;
+        }
+    }
+
+    io_service_ptr      m_io_service;
+    strand_ptr          m_strand;
+    context_ptr         m_context;
+    socket_ptr          m_socket;
+    uri_ptr             m_uri;
+    bool                m_is_server;
+
+    lib::error_code     m_ec;
+
+    connection_hdl      m_hdl;
+    socket_init_handler m_socket_init_handler;
+    tls_init_handler    m_tls_init_handler;
+};
+
+/// TLS enabled Asio endpoint socket component
+/**
+ * transport::asio::tls_socket::endpoint implements a secure endpoint socket
+ * component that uses Asio's ssl::stream to wrap an ip::tcp::socket.
+ */
+class endpoint {
+public:
+    /// The type of this endpoint socket component
+    typedef endpoint type;
+
+    /// The type of the corresponding connection socket component
+    typedef connection socket_con_type;
+    /// The type of a shared pointer to the corresponding connection socket
+    /// component.
+    typedef socket_con_type::ptr socket_con_ptr;
+
+    explicit endpoint() {}
+
+    /// Checks whether the endpoint creates secure connections
+    /**
+     * @return Whether or not the endpoint creates secure connections
+     */
+    bool is_secure() const {
+        return true;
+    }
+
+    /// Set socket init handler
+    /**
+     * The socket init handler is called after a connection's socket is created
+     * but before it is used. This gives the end application an opportunity to
+     * set asio socket specific parameters.
+     *
+     * @param h The new socket_init_handler
+     */
+    void set_socket_init_handler(socket_init_handler h) {
+        m_socket_init_handler = h;
+    }
+
+    /// Set TLS init handler
+    /**
+     * The tls init handler is called when needed to request a TLS context for
+     * the library to use. A TLS init handler must be set and it must return a
+     * valid TLS context in order for this endpoint to be able to initialize
+     * TLS connections
+     *
+     * @param h The new tls_init_handler
+     */
+    void set_tls_init_handler(tls_init_handler h) {
+        m_tls_init_handler = h;
+    }
+protected:
+    /// Initialize a connection
+    /**
+     * Called by the transport after a new connection is created to initialize
+     * the socket component of the connection.
+     *
+     * @param scon Pointer to the socket component of the connection
+     *
+     * @return Error code (empty on success)
+     */
+    lib::error_code init(socket_con_ptr scon) {
+        scon->set_socket_init_handler(m_socket_init_handler);
+        scon->set_tls_init_handler(m_tls_init_handler);
+        return lib::error_code();
+    }
+
+private:
+    socket_init_handler m_socket_init_handler;
+    tls_init_handler m_tls_init_handler;
+};
+
+} // namespace tls_socket
+} // namespace asio
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_SECURITY_TLS_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/base/connection.hpp b/subprojects/websocketpp/websocketpp/transport/base/connection.hpp
new file mode 100644
index 000000000..f76d40913
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/base/connection.hpp
@@ -0,0 +1,238 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_BASE_CON_HPP
+#define WEBSOCKETPP_TRANSPORT_BASE_CON_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/connection_hdl.hpp>
+#include <websocketpp/common/functional.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <string>
+
+namespace websocketpp {
+/// Transport policies provide network connectivity and timers
+/**
+ * ### Connection Interface
+ *
+ * Transport connection components needs to provide:
+ *
+ * **init**\n
+ * `void init(init_handler handler)`\n
+ * Called once shortly after construction to give the policy the chance to
+ * perform one time initialization. When complete, the policy must call the
+ * supplied `init_handler` to continue setup. The handler takes one argument
+ * with the error code if any. If an error is returned here setup will fail and
+ * the connection will be aborted or terminated.
+ *
+ * WebSocket++ will call init only once. The transport must call `handler`
+ * exactly once.
+ *
+ * **async_read_at_least**\n
+ * `void async_read_at_least(size_t num_bytes, char *buf, size_t len,
+ * read_handler handler)`\n
+ * start an async read for at least num_bytes and at most len
+ * bytes into buf. Call handler when done with number of bytes read.
+ *
+ * WebSocket++ promises to have only one async_read_at_least in flight at a
+ * time. The transport must promise to only call read_handler once per async
+ * read.
+ *
+ * **async_write**\n
+ * `void async_write(const char* buf, size_t len, write_handler handler)`\n
+ * `void async_write(std::vector<buffer> & bufs, write_handler handler)`\n
+ * Start a write of all of the data in buf or bufs. In second case data is
+ * written sequentially and in place without copying anything to a temporary
+ * location.
+ *
+ * Websocket++ promises to have only one async_write in flight at a time.
+ * The transport must promise to only call the write_handler once per async
+ * write
+ *
+ * **set_handle**\n
+ * `void set_handle(connection_hdl hdl)`\n
+ * Called by WebSocket++ to let this policy know the hdl to the connection. It
+ * may be stored for later use or ignored/discarded. This handle should be used
+ * if the policy adds any connection handlers. Connection handlers must be
+ * called with the handle as the first argument so that the handler code knows
+ * which connection generated the callback.
+ *
+ * **set_timer**\n
+ * `timer_ptr set_timer(long duration, timer_handler handler)`\n
+ * WebSocket++ uses the timers provided by the transport policy as the
+ * implementation of timers is often highly coupled with the implementation of
+ * the networking event loops.
+ *
+ * Transport timer support is an optional feature. A transport method may elect
+ * to implement a dummy timer object and have this method return an empty
+ * pointer. If so, all timer related features of WebSocket++ core will be
+ * disabled. This includes many security features designed to prevent denial of
+ * service attacks. Use timer-free transport policies with caution.
+ *
+ * **get_remote_endpoint**\n
+ * `std::string get_remote_endpoint()`\n
+ * retrieve address of remote endpoint
+ *
+ * **is_secure**\n
+ * `void is_secure()`\n
+ * whether or not the connection to the remote endpoint is secure
+ *
+ * **dispatch**\n
+ * `lib::error_code dispatch(dispatch_handler handler)`: invoke handler within
+ * the transport's event system if it uses one. Otherwise, this method should
+ * simply call `handler` immediately.
+ *
+ * **async_shutdown**\n
+ * `void async_shutdown(shutdown_handler handler)`\n
+ * Perform any cleanup necessary (if any). Call `handler` when complete.
+ */
+namespace transport {
+
+/// The type and signature of the callback passed to the init hook
+typedef lib::function<void(lib::error_code const &)> init_handler;
+
+/// The type and signature of the callback passed to the read method
+typedef lib::function<void(lib::error_code const &,size_t)> read_handler;
+
+/// The type and signature of the callback passed to the write method
+typedef lib::function<void(lib::error_code const &)> write_handler;
+
+/// The type and signature of the callback passed to the read method
+typedef lib::function<void(lib::error_code const &)> timer_handler;
+
+/// The type and signature of the callback passed to the shutdown method
+typedef lib::function<void(lib::error_code const &)> shutdown_handler;
+
+/// The type and signature of the callback passed to the interrupt method
+typedef lib::function<void()> interrupt_handler;
+
+/// The type and signature of the callback passed to the dispatch method
+typedef lib::function<void()> dispatch_handler;
+
+/// A simple utility buffer class
+struct buffer {
+    buffer(char const * b, size_t l) : buf(b),len(l) {}
+
+    char const * buf;
+    size_t len;
+};
+
+/// Generic transport related errors
+namespace error {
+enum value {
+    /// Catch-all error for transport policy errors that don't fit in other
+    /// categories
+    general = 1,
+
+    /// underlying transport pass through
+    pass_through,
+
+    /// async_read_at_least call requested more bytes than buffer can store
+    invalid_num_bytes,
+
+    /// async_read called while another async_read was in progress
+    double_read,
+
+    /// Operation aborted
+    operation_aborted,
+
+    /// Operation not supported
+    operation_not_supported,
+
+    /// End of file
+    eof,
+
+    /// TLS short read
+    tls_short_read,
+
+    /// Timer expired
+    timeout,
+
+    /// read or write after shutdown
+    action_after_shutdown,
+
+    /// Other TLS error
+    tls_error
+};
+
+class category : public lib::error_category {
+    public:
+    category() {}
+
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.transport";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case general:
+                return "Generic transport policy error";
+            case pass_through:
+                return "Underlying Transport Error";
+            case invalid_num_bytes:
+                return "async_read_at_least call requested more bytes than buffer can store";
+            case operation_aborted:
+                return "The operation was aborted";
+            case operation_not_supported:
+                return "The operation is not supported by this transport";
+            case eof:
+                return "End of File";
+            case tls_short_read:
+                return "TLS Short Read";
+            case timeout:
+                return "Timer Expired";
+            case action_after_shutdown:
+                return "A transport action was requested after shutdown";
+            case tls_error:
+                return "Generic TLS related error";
+            default:
+                return "Unknown";
+        }
+    }
+};
+
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace transport
+} // namespace websocketpp
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum<websocketpp::transport::error::value>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+
+#endif // WEBSOCKETPP_TRANSPORT_BASE_CON_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/base/endpoint.hpp b/subprojects/websocketpp/websocketpp/transport/base/endpoint.hpp
new file mode 100644
index 000000000..4ed3e70fa
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/base/endpoint.hpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_BASE_HPP
+#define WEBSOCKETPP_TRANSPORT_BASE_HPP
+
+#include <websocketpp/common/functional.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+namespace websocketpp {
+/// Transport policies provide network connectivity and timers
+/**
+ * ### Endpoint Interface
+ *
+ * Transport endpoint components needs to provide:
+ *
+ * **init**\n
+ * `lib::error_code init(transport_con_ptr tcon)`\n
+ * init is called by an endpoint once for each newly created connection.
+ * It's purpose is to give the transport policy the chance to perform any
+ * transport specific initialization that couldn't be done via the default
+ * constructor.
+ *
+ * **is_secure**\n
+ * `bool is_secure() const`\n
+ * Test whether the transport component of this endpoint is capable of secure
+ * connections.
+ *
+ * **async_connect**\n
+ * `void async_connect(transport_con_ptr tcon, uri_ptr location,
+ *  connect_handler handler)`\n
+ * Initiate a connection to `location` using the given connection `tcon`. `tcon`
+ * is a pointer to the transport connection component of the connection. When
+ * complete, `handler` should be called with the the connection's
+ * `connection_hdl` and any error that occurred.
+ *
+ * **init_logging**
+ * `void init_logging(const lib::shared_ptr<alog_type>& a, const lib::shared_ptr<elog_type>& e)`\n
+ * Called once after construction to provide pointers to the endpoint's access
+ * and error loggers. These may be stored and used to log messages or ignored.
+ */
+namespace transport {
+
+/// The type and signature of the callback passed to the accept method
+typedef lib::function<void(lib::error_code const &)> accept_handler;
+
+/// The type and signature of the callback passed to the connect method
+typedef lib::function<void(lib::error_code const &)> connect_handler;
+
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_BASE_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/iostream/base.hpp b/subprojects/websocketpp/websocketpp/transport/iostream/base.hpp
new file mode 100644
index 000000000..f87839878
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/iostream/base.hpp
@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_IOSTREAM_BASE_HPP
+#define WEBSOCKETPP_TRANSPORT_IOSTREAM_BASE_HPP
+
+#include <websocketpp/common/system_error.hpp>
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/functional.hpp>
+#include <websocketpp/common/connection_hdl.hpp>
+
+#include <websocketpp/transport/base/connection.hpp>
+
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace transport {
+/// Transport policy that uses STL iostream for I/O and does not support timers
+namespace iostream {
+
+/// The type and signature of the callback used by iostream transport to write
+typedef lib::function<lib::error_code(connection_hdl, char const *, size_t)>
+    write_handler;
+
+/// The type and signature of the callback used by iostream transport to perform
+/// vectored writes.
+/**
+ * If a vectored write handler is not set the standard write handler will be
+ * called multiple times.
+ */
+typedef lib::function<lib::error_code(connection_hdl, std::vector<transport::buffer> const
+    & bufs)> vector_write_handler;
+
+/// The type and signature of the callback used by iostream transport to signal
+/// a transport shutdown.
+typedef lib::function<lib::error_code(connection_hdl)> shutdown_handler;
+
+/// iostream transport errors
+namespace error {
+enum value {
+    /// Catch-all error for transport policy errors that don't fit in other
+    /// categories
+    general = 1,
+
+    /// async_read_at_least call requested more bytes than buffer can store
+    invalid_num_bytes,
+
+    /// async_read called while another async_read was in progress
+    double_read,
+
+    /// An operation that requires an output stream was attempted before
+    /// setting one.
+    output_stream_required,
+
+    /// stream error
+    bad_stream
+};
+
+/// iostream transport error category
+class category : public lib::error_category {
+    public:
+    category() {}
+
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.transport.iostream";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case general:
+                return "Generic iostream transport policy error";
+            case invalid_num_bytes:
+                return "async_read_at_least call requested more bytes than buffer can store";
+            case double_read:
+                return "Async read already in progress";
+            case output_stream_required:
+                return "An output stream to be set before async_write can be used";
+            case bad_stream:
+                return "A stream operation returned ios::bad";
+            default:
+                return "Unknown";
+        }
+    }
+};
+
+/// Get a reference to a static copy of the iostream transport error category
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+/// Get an error code with the given value and the iostream transport category
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace iostream
+} // namespace transport
+} // namespace websocketpp
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum<websocketpp::transport::iostream::error::value>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+
+#endif // WEBSOCKETPP_TRANSPORT_IOSTREAM_BASE_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/iostream/connection.hpp b/subprojects/websocketpp/websocketpp/transport/iostream/connection.hpp
new file mode 100644
index 000000000..899a3e256
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/iostream/connection.hpp
@@ -0,0 +1,714 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_IOSTREAM_CON_HPP
+#define WEBSOCKETPP_TRANSPORT_IOSTREAM_CON_HPP
+
+#include <websocketpp/transport/iostream/base.hpp>
+
+#include <websocketpp/transport/base/connection.hpp>
+
+#include <websocketpp/uri.hpp>
+
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/connection_hdl.hpp>
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/common/platforms.hpp>
+
+#include <algorithm>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace transport {
+namespace iostream {
+
+/// Empty timer class to stub out for timer functionality that iostream
+/// transport doesn't support
+struct timer {
+    void cancel() {}
+};
+
+template <typename config>
+class connection : public lib::enable_shared_from_this< connection<config> > {
+public:
+    /// Type of this connection transport component
+    typedef connection<config> type;
+    /// Type of a shared pointer to this connection transport component
+    typedef lib::shared_ptr<type> ptr;
+
+    /// transport concurrency policy
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of this transport's access logging policy
+    typedef typename config::alog_type alog_type;
+    /// Type of this transport's error logging policy
+    typedef typename config::elog_type elog_type;
+
+    // Concurrency policy types
+    typedef typename concurrency_type::scoped_lock_type scoped_lock_type;
+    typedef typename concurrency_type::mutex_type mutex_type;
+
+    typedef lib::shared_ptr<timer> timer_ptr;
+
+    explicit connection(bool is_server, const lib::shared_ptr<alog_type> & alog, const lib::shared_ptr<elog_type> & elog)
+      : m_output_stream(NULL)
+      , m_reading(false)
+      , m_is_server(is_server)
+      , m_is_secure(false)
+      , m_alog(alog)
+      , m_elog(elog)
+      , m_remote_endpoint("iostream transport")
+    {
+        m_alog->write(log::alevel::devel,"iostream con transport constructor");
+    }
+
+    /// Get a shared pointer to this component
+    ptr get_shared() {
+        return type::shared_from_this();
+    }
+
+    /// Register a std::ostream with the transport for writing output
+    /**
+     * Register a std::ostream with the transport. All future writes will be
+     * done to this output stream.
+     *
+     * @param o A pointer to the ostream to use for output.
+     */
+    void register_ostream(std::ostream * o) {
+        // TODO: lock transport state?
+        scoped_lock_type lock(m_read_mutex);
+        m_output_stream = o;
+    }
+
+    /// Set uri hook
+    /**
+     * Called by the endpoint as a connection is being established to provide
+     * the uri being connected to to the transport layer.
+     *
+     * This transport policy doesn't use the uri so it is ignored.
+     *
+     * @since 0.6.0
+     *
+     * @param u The uri to set
+     */
+    void set_uri(uri_ptr) {}
+
+    /// Overloaded stream input operator
+    /**
+     * Attempts to read input from the given stream into the transport. Bytes
+     * will be extracted from the input stream to fulfill any pending reads.
+     * Input in this manner will only read until the current read buffer has
+     * been filled. Then it will signal the library to process the input. If the
+     * library's input handler adds a new async_read, additional bytes will be
+     * read, otherwise the input operation will end.
+     *
+     * When this function returns one of the following conditions is true:
+     * - There is no outstanding read operation
+     * - There are no more bytes available in the input stream
+     *
+     * You can use tellg() on the input stream to determine if all of the input
+     * bytes were read or not.
+     *
+     * If there is no pending read operation when the input method is called, it
+     * will return immediately and tellg() will not have changed.
+     */
+    friend std::istream & operator>> (std::istream & in, type & t) {
+        // this serializes calls to external read.
+        scoped_lock_type lock(t.m_read_mutex);
+
+        t.read(in);
+
+        return in;
+    }
+
+    /// Manual input supply (read some)
+    /**
+     * Copies bytes from buf into WebSocket++'s input buffers. Bytes will be
+     * copied from the supplied buffer to fulfill any pending library reads. It
+     * will return the number of bytes successfully processed. If there are no
+     * pending reads read_some will return immediately. Not all of the bytes may
+     * be able to be read in one call.
+     *
+     * @since 0.3.0-alpha4
+     *
+     * @param buf Char buffer to read into the websocket
+     * @param len Length of buf
+     * @return The number of characters from buf actually read.
+     */
+    size_t read_some(char const * buf, size_t len) {
+        // this serializes calls to external read.
+        scoped_lock_type lock(m_read_mutex);
+
+        return this->read_some_impl(buf,len);
+    }
+
+    /// Manual input supply (read all)
+    /**
+     * Similar to read_some, but continues to read until all bytes in the
+     * supplied buffer have been read or the connection runs out of read
+     * requests.
+     *
+     * This method still may not read all of the bytes in the input buffer. if
+     * it doesn't it indicates that the connection was most likely closed or
+     * is in an error state where it is no longer accepting new input.
+     *
+     * @since 0.3.0
+     *
+     * @param buf Char buffer to read into the websocket
+     * @param len Length of buf
+     * @return The number of characters from buf actually read.
+     */
+    size_t read_all(char const * buf, size_t len) {
+        // this serializes calls to external read.
+        scoped_lock_type lock(m_read_mutex);
+
+        size_t total_read = 0;
+        size_t temp_read = 0;
+
+        do {
+            temp_read = this->read_some_impl(buf+total_read,len-total_read);
+            total_read += temp_read;
+        } while (temp_read != 0 && total_read < len);
+
+        return total_read;
+    }
+
+    /// Manual input supply (DEPRECATED)
+    /**
+     * @deprecated DEPRECATED in favor of read_some()
+     * @see read_some()
+     */
+    size_t readsome(char const * buf, size_t len) {
+        return this->read_some(buf,len);
+    }
+
+    /// Signal EOF
+    /**
+     * Signals to the transport that data stream being read has reached EOF and
+     * that no more bytes may be read or written to/from the transport.
+     *
+     * @since 0.3.0-alpha4
+     */
+    void eof() {
+        // this serializes calls to external read.
+        scoped_lock_type lock(m_read_mutex);
+
+        if (m_reading) {
+            complete_read(make_error_code(transport::error::eof));
+        }
+    }
+
+    /// Signal transport error
+    /**
+     * Signals to the transport that a fatal data stream error has occurred and
+     * that no more bytes may be read or written to/from the transport.
+     *
+     * @since 0.3.0-alpha4
+     */
+    void fatal_error() {
+        // this serializes calls to external read.
+        scoped_lock_type lock(m_read_mutex);
+
+        if (m_reading) {
+            complete_read(make_error_code(transport::error::pass_through));
+        }
+    }
+
+    /// Set whether or not this connection is secure
+    /**
+     * The iostream transport does not provide any security features. As such
+     * it defaults to returning false when `is_secure` is called. However, the
+     * iostream transport may be used to wrap an external socket API that may
+     * provide secure transport. This method allows that external API to flag
+     * whether or not this connection is secure so that users of the WebSocket++
+     * API will get more accurate information.
+     *
+     * @since 0.3.0-alpha4
+     *
+     * @param value Whether or not this connection is secure.
+     */
+    void set_secure(bool value) {
+        m_is_secure = value;
+    }
+
+    /// Tests whether or not the underlying transport is secure
+    /**
+     * iostream transport will return false always because it has no information
+     * about the ultimate remote endpoint. This may or may not be accurate
+     * depending on the real source of bytes being input. The `set_secure`
+     * method may be used to flag connections that are secured by an external
+     * API
+     *
+     * @return Whether or not the underlying transport is secure
+     */
+    bool is_secure() const {
+        return m_is_secure;
+    }
+
+    /// Set human readable remote endpoint address
+    /**
+     * Sets the remote endpoint address returned by `get_remote_endpoint`. This
+     * value should be a human readable string that describes the remote
+     * endpoint. Typically an IP address or hostname, perhaps with a port. But
+     * may be something else depending on the nature of the underlying
+     * transport.
+     *
+     * If none is set the default is "iostream transport".
+     *
+     * @since 0.3.0-alpha4
+     *
+     * @param value The remote endpoint address to set.
+     */
+    void set_remote_endpoint(std::string value) {
+        m_remote_endpoint = value;
+    }
+
+    /// Get human readable remote endpoint address
+    /**
+     * The iostream transport has no information about the ultimate remote
+     * endpoint. It will return the string "iostream transport". The
+     * `set_remote_endpoint` method may be used by external network code to set
+     * a more accurate value.
+     *
+     * This value is used in access and error logs and is available to the end
+     * application for including in user facing interfaces and messages.
+     *
+     * @return A string identifying the address of the remote endpoint
+     */
+    std::string get_remote_endpoint() const {
+        return m_remote_endpoint;
+    }
+
+    /// Get the connection handle
+    /**
+     * @return The handle for this connection.
+     */
+    connection_hdl get_handle() const {
+        return m_connection_hdl;
+    }
+
+    /// Call back a function after a period of time.
+    /**
+     * Timers are not implemented in this transport. The timer pointer will
+     * always be empty. The handler will never be called.
+     *
+     * @param duration Length of time to wait in milliseconds
+     * @param callback The function to call back when the timer has expired
+     * @return A handle that can be used to cancel the timer if it is no longer
+     * needed.
+     */
+    timer_ptr set_timer(long, timer_handler) {
+        return timer_ptr();
+    }
+
+    /// Sets the write handler
+    /**
+     * The write handler is called when the iostream transport receives data
+     * that needs to be written to the appropriate output location. This handler
+     * can be used in place of registering an ostream for output.
+     *
+     * The signature of the handler is
+     * `lib::error_code (connection_hdl, char const *, size_t)` The
+     * code returned will be reported and logged by the core library.
+     *
+     * See also, set_vector_write_handler, for an optional write handler that
+     * allows more efficient handling of multiple writes at once.
+     *
+     * @see set_vector_write_handler
+     *
+     * @since 0.5.0
+     *
+     * @param h The handler to call when data is to be written.
+     */
+    void set_write_handler(write_handler h) {
+        m_write_handler = h;
+    }
+
+    /// Sets the vectored write handler
+    /**
+     * The vectored write handler is called when the iostream transport receives
+     * multiple chunks of data that need to be written to the appropriate output
+     * location. This handler can be used in conjunction with the write_handler
+     * in place of registering an ostream for output.
+     *
+     * The sequence of buffers represents bytes that should be written
+     * consecutively and it is suggested to group the buffers into as few next
+     * layer packets as possible. Vector write is used to allow implementations
+     * that support it to coalesce writes into a single TCP packet or TLS
+     * segment for improved efficiency.
+     *
+     * This is an optional handler. If it is not defined then multiple calls
+     * will be made to the standard write handler.
+     *
+     * The signature of the handler is
+     * `lib::error_code (connection_hdl, std::vector<websocketpp::transport::buffer>
+     * const & bufs)`. The code returned will be reported and logged by the core
+     * library. The `websocketpp::transport::buffer` type is a struct with two
+     * data members. buf (char const *) and len (size_t).
+     *
+     * @since 0.6.0
+     *
+     * @param h The handler to call when vectored data is to be written.
+     */
+    void set_vector_write_handler(vector_write_handler h) {
+        m_vector_write_handler = h;
+    }
+
+    /// Sets the shutdown handler
+    /**
+     * The shutdown handler is called when the iostream transport receives a
+     * notification from the core library that it is finished with all read and
+     * write operations and that the underlying transport can be cleaned up.
+     *
+     * If you are using iostream transport with another socket library, this is
+     * a good time to close/shutdown the socket for this connection.
+     *
+     * The signature of the handler is `lib::error_code (connection_hdl)`. The
+     * code returned will be reported and logged by the core library.
+     *
+     * @since 0.5.0
+     *
+     * @param h The handler to call on connection shutdown.
+     */
+    void set_shutdown_handler(shutdown_handler h) {
+        m_shutdown_handler = h;
+    }
+protected:
+    /// Initialize the connection transport
+    /**
+     * Initialize the connection's transport component.
+     *
+     * @param handler The `init_handler` to call when initialization is done
+     */
+    void init(init_handler handler) {
+        m_alog->write(log::alevel::devel,"iostream connection init");
+        handler(lib::error_code());
+    }
+
+    /// Initiate an async_read for at least num_bytes bytes into buf
+    /**
+     * Initiates an async_read request for at least num_bytes bytes. The input
+     * will be read into buf. A maximum of len bytes will be input. When the
+     * operation is complete, handler will be called with the status and number
+     * of bytes read.
+     *
+     * This method may or may not call handler from within the initial call. The
+     * application should be prepared to accept either.
+     *
+     * The application should never call this method a second time before it has
+     * been called back for the first read. If this is done, the second read
+     * will be called back immediately with a double_read error.
+     *
+     * If num_bytes or len are zero handler will be called back immediately
+     * indicating success.
+     *
+     * @param num_bytes Don't call handler until at least this many bytes have
+     * been read.
+     * @param buf The buffer to read bytes into
+     * @param len The size of buf. At maximum, this many bytes will be read.
+     * @param handler The callback to invoke when the operation is complete or
+     * ends in an error
+     */
+    void async_read_at_least(size_t num_bytes, char *buf, size_t len,
+        read_handler handler)
+    {
+        std::stringstream s;
+        s << "iostream_con async_read_at_least: " << num_bytes;
+        m_alog->write(log::alevel::devel,s.str());
+
+        if (num_bytes > len) {
+            handler(make_error_code(error::invalid_num_bytes),size_t(0));
+            return;
+        }
+
+        if (m_reading == true) {
+            handler(make_error_code(error::double_read),size_t(0));
+            return;
+        }
+
+        if (num_bytes == 0 || len == 0) {
+            handler(lib::error_code(),size_t(0));
+            return;
+        }
+
+        m_buf = buf;
+        m_len = len;
+        m_bytes_needed = num_bytes;
+        m_read_handler = handler;
+        m_cursor = 0;
+        m_reading = true;
+    }
+
+    /// Asyncronous Transport Write
+    /**
+     * Write len bytes in buf to the output method. Call handler to report
+     * success or failure. handler may or may not be called during async_write,
+     * but it must be safe for this to happen.
+     *
+     * Will return 0 on success. Other possible errors (not exhaustive)
+     * output_stream_required: No output stream was registered to write to
+     * bad_stream: a ostream pass through error
+     *
+     * This method will attempt to write to the registered ostream first. If an
+     * ostream is not registered it will use the write handler. If neither are
+     * registered then an error is passed up to the connection.
+     *
+     * @param buf buffer to read bytes from
+     * @param len number of bytes to write
+     * @param handler Callback to invoke with operation status.
+     */
+    void async_write(char const * buf, size_t len, transport::write_handler
+        handler)
+    {
+        m_alog->write(log::alevel::devel,"iostream_con async_write");
+        // TODO: lock transport state?
+
+        lib::error_code ec;
+
+        if (m_output_stream) {
+            m_output_stream->write(buf,len);
+
+            if (m_output_stream->bad()) {
+                ec = make_error_code(error::bad_stream);
+            }
+        } else if (m_write_handler) {
+            ec = m_write_handler(m_connection_hdl, buf, len);
+        } else {
+            ec = make_error_code(error::output_stream_required);
+        }
+
+        handler(ec);
+    }
+
+    /// Asyncronous Transport Write (scatter-gather)
+    /**
+     * Write a sequence of buffers to the output method. Call handler to report
+     * success or failure. handler may or may not be called during async_write,
+     * but it must be safe for this to happen.
+     *
+     * Will return 0 on success. Other possible errors (not exhaustive)
+     * output_stream_required: No output stream was registered to write to
+     * bad_stream: a ostream pass through error
+     *
+     * This method will attempt to write to the registered ostream first. If an
+     * ostream is not registered it will use the write handler. If neither are
+     * registered then an error is passed up to the connection.
+     *
+     * @param bufs vector of buffers to write
+     * @param handler Callback to invoke with operation status.
+     */
+    void async_write(std::vector<buffer> const & bufs, transport::write_handler
+        handler)
+    {
+        m_alog->write(log::alevel::devel,"iostream_con async_write buffer list");
+        // TODO: lock transport state?
+
+        lib::error_code ec;
+
+        if (m_output_stream) {
+            std::vector<buffer>::const_iterator it;
+            for (it = bufs.begin(); it != bufs.end(); it++) {
+                m_output_stream->write((*it).buf,(*it).len);
+
+                if (m_output_stream->bad()) {
+                    ec = make_error_code(error::bad_stream);
+                    break;
+                }
+            }
+        } else if (m_vector_write_handler) {
+            ec = m_vector_write_handler(m_connection_hdl, bufs);
+        } else if (m_write_handler) {
+            std::vector<buffer>::const_iterator it;
+            for (it = bufs.begin(); it != bufs.end(); it++) {
+                ec = m_write_handler(m_connection_hdl, (*it).buf, (*it).len);
+                if (ec) {break;}
+            }
+
+        } else {
+            ec = make_error_code(error::output_stream_required);
+        }
+
+        handler(ec);
+    }
+
+    /// Set Connection Handle
+    /**
+     * @param hdl The new handle
+     */
+    void set_handle(connection_hdl hdl) {
+        m_connection_hdl = hdl;
+    }
+
+    /// Call given handler back within the transport's event system (if present)
+    /**
+     * Invoke a callback within the transport's event system if it has one. If
+     * it doesn't, the handler will be invoked immediately before this function
+     * returns.
+     *
+     * @param handler The callback to invoke
+     *
+     * @return Whether or not the transport was able to register the handler for
+     * callback.
+     */
+    lib::error_code dispatch(dispatch_handler handler) {
+        handler();
+        return lib::error_code();
+    }
+
+    /// Perform cleanup on socket shutdown_handler
+    /**
+     * If a shutdown handler is set, call it and pass through its return error
+     * code. Otherwise assume there is nothing to do and pass through a success
+     * code.
+     *
+     * @param handler The `shutdown_handler` to call back when complete
+     */
+    void async_shutdown(transport::shutdown_handler handler) {
+        lib::error_code ec;
+
+        if (m_shutdown_handler) {
+            ec = m_shutdown_handler(m_connection_hdl);
+        }
+
+        handler(ec);
+    }
+private:
+    void read(std::istream &in) {
+        m_alog->write(log::alevel::devel,"iostream_con read");
+
+        while (in.good()) {
+            if (!m_reading) {
+                m_elog->write(log::elevel::devel,"write while not reading");
+                break;
+            }
+
+            in.read(m_buf+m_cursor,static_cast<std::streamsize>(m_len-m_cursor));
+
+            if (in.gcount() == 0) {
+                m_elog->write(log::elevel::devel,"read zero bytes");
+                break;
+            }
+
+            m_cursor += static_cast<size_t>(in.gcount());
+
+            // TODO: error handling
+            if (in.bad()) {
+                m_reading = false;
+                complete_read(make_error_code(error::bad_stream));
+            }
+
+            if (m_cursor >= m_bytes_needed) {
+                m_reading = false;
+                complete_read(lib::error_code());
+            }
+        }
+    }
+
+    size_t read_some_impl(char const * buf, size_t len) {
+        m_alog->write(log::alevel::devel,"iostream_con read_some");
+
+        if (!m_reading) {
+            m_elog->write(log::elevel::devel,"write while not reading");
+            return 0;
+        }
+
+        size_t bytes_to_copy = (std::min)(len,m_len-m_cursor);
+
+        std::copy(buf,buf+bytes_to_copy,m_buf+m_cursor);
+
+        m_cursor += bytes_to_copy;
+
+        if (m_cursor >= m_bytes_needed) {
+            complete_read(lib::error_code());
+        }
+
+        return bytes_to_copy;
+    }
+
+    /// Signal that a requested read is complete
+    /**
+     * Sets the reading flag to false and returns the handler that should be
+     * called back with the result of the read. The cursor position that is sent
+     * is whatever the value of m_cursor is.
+     *
+     * It MUST NOT be called when m_reading is false.
+     * it MUST be called while holding the read lock
+     *
+     * It is important to use this method rather than directly setting/calling
+     * m_read_handler back because this function makes sure to delete the
+     * locally stored handler which contains shared pointers that will otherwise
+     * cause circular reference based memory leaks.
+     *
+     * @param ec The error code to forward to the read handler
+     */
+    void complete_read(lib::error_code const & ec) {
+        m_reading = false;
+
+        read_handler handler = m_read_handler;
+        m_read_handler = read_handler();
+
+        handler(ec,m_cursor);
+    }
+
+    // Read space (Protected by m_read_mutex)
+    char *          m_buf;
+    size_t          m_len;
+    size_t          m_bytes_needed;
+    read_handler    m_read_handler;
+    size_t          m_cursor;
+
+    // transport resources
+    std::ostream *  m_output_stream;
+    connection_hdl  m_connection_hdl;
+    write_handler   m_write_handler;
+    vector_write_handler m_vector_write_handler;
+    shutdown_handler    m_shutdown_handler;
+
+    bool            m_reading;
+    bool const      m_is_server;
+    bool            m_is_secure;
+    lib::shared_ptr<alog_type>     m_alog;
+    lib::shared_ptr<elog_type>     m_elog;
+    std::string     m_remote_endpoint;
+
+    // This lock ensures that only one thread can edit read data for this
+    // connection. This is a very coarse lock that is basically locked all the
+    // time. The nature of the connection is such that it cannot be
+    // parallelized, the locking is here to prevent intra-connection concurrency
+    // in order to allow inter-connection concurrency.
+    mutex_type      m_read_mutex;
+};
+
+
+} // namespace iostream
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_IOSTREAM_CON_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/iostream/endpoint.hpp b/subprojects/websocketpp/websocketpp/transport/iostream/endpoint.hpp
new file mode 100644
index 000000000..14cba7255
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/iostream/endpoint.hpp
@@ -0,0 +1,222 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_IOSTREAM_HPP
+#define WEBSOCKETPP_TRANSPORT_IOSTREAM_HPP
+
+#include <websocketpp/transport/base/endpoint.hpp>
+#include <websocketpp/transport/iostream/connection.hpp>
+
+#include <websocketpp/uri.hpp>
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/memory.hpp>
+
+#include <ostream>
+
+namespace websocketpp {
+namespace transport {
+namespace iostream {
+
+template <typename config>
+class endpoint {
+public:
+    /// Type of this endpoint transport component
+    typedef endpoint type;
+    /// Type of a pointer to this endpoint transport component
+    typedef lib::shared_ptr<type> ptr;
+
+    /// Type of this endpoint's concurrency policy
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of this endpoint's error logging policy
+    typedef typename config::elog_type elog_type;
+    /// Type of this endpoint's access logging policy
+    typedef typename config::alog_type alog_type;
+
+    /// Type of this endpoint transport component's associated connection
+    /// transport component.
+    typedef iostream::connection<config> transport_con_type;
+    /// Type of a shared pointer to this endpoint transport component's
+    /// associated connection transport component
+    typedef typename transport_con_type::ptr transport_con_ptr;
+
+    // generate and manage our own io_service
+    explicit endpoint() : m_output_stream(NULL), m_is_secure(false)
+    {
+        //std::cout << "transport::iostream::endpoint constructor" << std::endl;
+    }
+
+    /// Register a default output stream
+    /**
+     * The specified output stream will be assigned to future connections as the
+     * default output stream.
+     *
+     * @param o The ostream to use as the default output stream.
+     */
+    void register_ostream(std::ostream * o) {
+        m_alog->write(log::alevel::devel,"register_ostream");
+        m_output_stream = o;
+    }
+
+    /// Set whether or not endpoint can create secure connections
+    /**
+     * The iostream transport does not provide any security features. As such
+     * it defaults to returning false when `is_secure` is called. However, the
+     * iostream transport may be used to wrap an external socket API that may
+     * provide secure transport. This method allows that external API to flag
+     * whether or not it can create secure connections so that users of the
+     * WebSocket++ API will get more accurate information.
+     *
+     * Setting this value only indicates whether or not the endpoint is capable
+     * of producing and managing secure connections. Connections produced by
+     * this endpoint must also be individually flagged as secure if they are.
+     *
+     * @since 0.3.0-alpha4
+     *
+     * @param value Whether or not the endpoint can create secure connections.
+     */
+    void set_secure(bool value) {
+        m_is_secure = value;
+    }
+
+    /// Tests whether or not the underlying transport is secure
+    /**
+     * iostream transport will return false by default because it has no
+     * information about the ultimate remote endpoint. This may or may not be
+     * accurate depending on the real source of bytes being input. `set_secure`
+     * may be used by a wrapper API to correct the return value in the case that
+     * secure connections are in fact possible.
+     *
+     * @return Whether or not the underlying transport is secure
+     */
+    bool is_secure() const {
+        return m_is_secure;
+    }
+    
+    /// Sets the write handler
+    /**
+     * The write handler is called when the iostream transport receives data
+     * that needs to be written to the appropriate output location. This handler
+     * can be used in place of registering an ostream for output.
+     *
+     * The signature of the handler is 
+     * `lib::error_code (connection_hdl, char const *, size_t)` The
+     * code returned will be reported and logged by the core library.
+     *
+     * @since 0.5.0
+     *
+     * @param h The handler to call on connection shutdown.
+     */
+    void set_write_handler(write_handler h) {
+        m_write_handler = h;
+    }
+    
+    /// Sets the shutdown handler
+    /**
+     * The shutdown handler is called when the iostream transport receives a
+     * notification from the core library that it is finished with all read and
+     * write operations and that the underlying transport can be cleaned up.
+     *
+     * If you are using iostream transport with another socket library, this is
+     * a good time to close/shutdown the socket for this connection.
+     *
+     * The signature of the handler is lib::error_code (connection_hdl). The
+     * code returned will be reported and logged by the core library.
+     *
+     * @since 0.5.0
+     *
+     * @param h The handler to call on connection shutdown.
+     */
+    void set_shutdown_handler(shutdown_handler h) {
+        m_shutdown_handler = h;
+    }
+protected:
+    /// Initialize logging
+    /**
+     * The loggers are located in the main endpoint class. As such, the
+     * transport doesn't have direct access to them. This method is called
+     * by the endpoint constructor to allow shared logging from the transport
+     * component. These are raw pointers to member variables of the endpoint.
+     * In particular, they cannot be used in the transport constructor as they
+     * haven't been constructed yet, and cannot be used in the transport
+     * destructor as they will have been destroyed by then.
+     *
+     * @param a A pointer to the access logger to use.
+     * @param e A pointer to the error logger to use.
+     */
+    void init_logging(lib::shared_ptr<alog_type> a, lib::shared_ptr<elog_type> e) {
+        m_elog = e;
+        m_alog = a;
+    }
+
+    /// Initiate a new connection
+    /**
+     * @param tcon A pointer to the transport connection component of the
+     * connection to connect.
+     * @param u A URI pointer to the URI to connect to.
+     * @param cb The function to call back with the results when complete.
+     */
+    void async_connect(transport_con_ptr, uri_ptr, connect_handler cb) {
+        cb(lib::error_code());
+    }
+
+    /// Initialize a connection
+    /**
+     * Init is called by an endpoint once for each newly created connection.
+     * It's purpose is to give the transport policy the chance to perform any
+     * transport specific initialization that couldn't be done via the default
+     * constructor.
+     *
+     * @param tcon A pointer to the transport portion of the connection.
+     * @return A status code indicating the success or failure of the operation
+     */
+    lib::error_code init(transport_con_ptr tcon) {
+        tcon->register_ostream(m_output_stream);
+        if (m_shutdown_handler) {
+            tcon->set_shutdown_handler(m_shutdown_handler);
+        }
+        if (m_write_handler) {
+            tcon->set_write_handler(m_write_handler);
+        }
+        return lib::error_code();
+    }
+private:
+    std::ostream *  m_output_stream;
+    shutdown_handler m_shutdown_handler;
+    write_handler   m_write_handler;
+    
+    lib::shared_ptr<elog_type>     m_elog;
+    lib::shared_ptr<alog_type>     m_alog;
+    bool            m_is_secure;
+};
+
+
+} // namespace iostream
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_IOSTREAM_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/stub/base.hpp b/subprojects/websocketpp/websocketpp/transport/stub/base.hpp
new file mode 100644
index 000000000..754981e29
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/stub/base.hpp
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_STUB_BASE_HPP
+#define WEBSOCKETPP_TRANSPORT_STUB_BASE_HPP
+
+#include <websocketpp/common/system_error.hpp>
+#include <websocketpp/common/cpp11.hpp>
+
+#include <string>
+
+namespace websocketpp {
+namespace transport {
+/// Stub transport policy that has no input or output.
+namespace stub {
+
+/// stub transport errors
+namespace error {
+enum value {
+    /// Catch-all error for transport policy errors that don't fit in other
+    /// categories
+    general = 1,
+
+    /// not implemented
+    not_implemented
+};
+
+/// stub transport error category
+class category : public lib::error_category {
+    public:
+    category() {}
+
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.transport.stub";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case general:
+                return "Generic stub transport policy error";
+            case not_implemented:
+                return "feature not implemented";
+            default:
+                return "Unknown";
+        }
+    }
+};
+
+/// Get a reference to a static copy of the stub transport error category
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+/// Get an error code with the given value and the stub transport category
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace stub
+} // namespace transport
+} // namespace websocketpp
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum<websocketpp::transport::stub::error::value>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+
+#endif // WEBSOCKETPP_TRANSPORT_STUB_BASE_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/stub/connection.hpp b/subprojects/websocketpp/websocketpp/transport/stub/connection.hpp
new file mode 100644
index 000000000..5bbbf0d79
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/stub/connection.hpp
@@ -0,0 +1,286 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_STUB_CON_HPP
+#define WEBSOCKETPP_TRANSPORT_STUB_CON_HPP
+
+#include <websocketpp/transport/stub/base.hpp>
+
+#include <websocketpp/transport/base/connection.hpp>
+
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/common/connection_hdl.hpp>
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/common/platforms.hpp>
+
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace transport {
+namespace stub {
+
+/// Empty timer class to stub out for timer functionality that stub
+/// transport doesn't support
+struct timer {
+    void cancel() {}
+};
+
+template <typename config>
+class connection : public lib::enable_shared_from_this< connection<config> > {
+public:
+    /// Type of this connection transport component
+    typedef connection<config> type;
+    /// Type of a shared pointer to this connection transport component
+    typedef lib::shared_ptr<type> ptr;
+
+    /// transport concurrency policy
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of this transport's access logging policy
+    typedef typename config::alog_type alog_type;
+    /// Type of this transport's error logging policy
+    typedef typename config::elog_type elog_type;
+
+    // Concurrency policy types
+    typedef typename concurrency_type::scoped_lock_type scoped_lock_type;
+    typedef typename concurrency_type::mutex_type mutex_type;
+
+    typedef lib::shared_ptr<timer> timer_ptr;
+
+    explicit connection(bool is_server, const lib::shared_ptr<alog_type> & alog, const lib::shared_ptr<elog_type> & elog)
+      : m_alog(alog), m_elog(elog)
+    {
+        m_alog->write(log::alevel::devel,"stub con transport constructor");
+    }
+
+    /// Get a shared pointer to this component
+    ptr get_shared() {
+        return type::shared_from_this();
+    }
+
+    /// Set whether or not this connection is secure
+    /**
+     * Todo: docs
+     *
+     * @since 0.3.0-alpha4
+     *
+     * @param value Whether or not this connection is secure.
+     */
+    void set_secure(bool value) {}
+
+    /// Tests whether or not the underlying transport is secure
+    /**
+     * TODO: docs
+     *
+     * @return Whether or not the underlying transport is secure
+     */
+    bool is_secure() const {
+        return false;
+    }
+
+    /// Set uri hook
+    /**
+     * Called by the endpoint as a connection is being established to provide
+     * the uri being connected to to the transport layer.
+     *
+     * Implementation is optional and can be ignored if the transport has no
+     * need for this information.
+     *
+     * @since 0.6.0
+     *
+     * @param u The uri to set
+     */
+    void set_uri(uri_ptr) {}
+
+    /// Set human readable remote endpoint address
+    /**
+     * Sets the remote endpoint address returned by `get_remote_endpoint`. This
+     * value should be a human readable string that describes the remote
+     * endpoint. Typically an IP address or hostname, perhaps with a port. But
+     * may be something else depending on the nature of the underlying
+     * transport.
+     *
+     * If none is set a default is returned.
+     *
+     * @since 0.3.0-alpha4
+     *
+     * @param value The remote endpoint address to set.
+     */
+    void set_remote_endpoint(std::string value) {}
+
+    /// Get human readable remote endpoint address
+    /**
+     * TODO: docs
+     *
+     * This value is used in access and error logs and is available to the end
+     * application for including in user facing interfaces and messages.
+     *
+     * @return A string identifying the address of the remote endpoint
+     */
+    std::string get_remote_endpoint() const {
+        return "unknown (stub transport)";
+    }
+
+    /// Get the connection handle
+    /**
+     * @return The handle for this connection.
+     */
+    connection_hdl get_handle() const {
+        return connection_hdl();
+    }
+
+    /// Call back a function after a period of time.
+    /**
+     * Timers are not implemented in this transport. The timer pointer will
+     * always be empty. The handler will never be called.
+     *
+     * @param duration Length of time to wait in milliseconds
+     * @param callback The function to call back when the timer has expired
+     * @return A handle that can be used to cancel the timer if it is no longer
+     * needed.
+     */
+    timer_ptr set_timer(long duration, timer_handler handler) {
+        return timer_ptr();
+    }
+protected:
+    /// Initialize the connection transport
+    /**
+     * Initialize the connection's transport component.
+     *
+     * @param handler The `init_handler` to call when initialization is done
+     */
+    void init(init_handler handler) {
+        m_alog->write(log::alevel::devel,"stub connection init");
+        handler(make_error_code(error::not_implemented));
+    }
+
+    /// Initiate an async_read for at least num_bytes bytes into buf
+    /**
+     * Initiates an async_read request for at least num_bytes bytes. The input
+     * will be read into buf. A maximum of len bytes will be input. When the
+     * operation is complete, handler will be called with the status and number
+     * of bytes read.
+     *
+     * This method may or may not call handler from within the initial call. The
+     * application should be prepared to accept either.
+     *
+     * The application should never call this method a second time before it has
+     * been called back for the first read. If this is done, the second read
+     * will be called back immediately with a double_read error.
+     *
+     * If num_bytes or len are zero handler will be called back immediately
+     * indicating success.
+     *
+     * @param num_bytes Don't call handler until at least this many bytes have
+     * been read.
+     * @param buf The buffer to read bytes into
+     * @param len The size of buf. At maximum, this many bytes will be read.
+     * @param handler The callback to invoke when the operation is complete or
+     * ends in an error
+     */
+    void async_read_at_least(size_t num_bytes, char * buf, size_t len,
+        read_handler handler)
+    {
+        m_alog->write(log::alevel::devel, "stub_con async_read_at_least");
+        handler(make_error_code(error::not_implemented), 0);
+    }
+
+    /// Asyncronous Transport Write
+    /**
+     * Write len bytes in buf to the output stream. Call handler to report
+     * success or failure. handler may or may not be called during async_write,
+     * but it must be safe for this to happen.
+     *
+     * Will return 0 on success.
+     *
+     * @param buf buffer to read bytes from
+     * @param len number of bytes to write
+     * @param handler Callback to invoke with operation status.
+     */
+    void async_write(char const * buf, size_t len, write_handler handler) {
+        m_alog->write(log::alevel::devel,"stub_con async_write");
+        handler(make_error_code(error::not_implemented));
+    }
+
+    /// Asyncronous Transport Write (scatter-gather)
+    /**
+     * Write a sequence of buffers to the output stream. Call handler to report
+     * success or failure. handler may or may not be called during async_write,
+     * but it must be safe for this to happen.
+     *
+     * Will return 0 on success.
+     *
+     * @param bufs vector of buffers to write
+     * @param handler Callback to invoke with operation status.
+     */
+    void async_write(std::vector<buffer> const & bufs, write_handler handler) {
+        m_alog->write(log::alevel::devel,"stub_con async_write buffer list");
+        handler(make_error_code(error::not_implemented));
+    }
+
+    /// Set Connection Handle
+    /**
+     * @param hdl The new handle
+     */
+    void set_handle(connection_hdl hdl) {}
+
+    /// Call given handler back within the transport's event system (if present)
+    /**
+     * Invoke a callback within the transport's event system if it has one. If
+     * it doesn't, the handler will be invoked immediately before this function
+     * returns.
+     *
+     * @param handler The callback to invoke
+     *
+     * @return Whether or not the transport was able to register the handler for
+     * callback.
+     */
+    lib::error_code dispatch(dispatch_handler handler) {
+        handler();
+        return lib::error_code();
+    }
+
+    /// Perform cleanup on socket shutdown_handler
+    /**
+     * @param h The `shutdown_handler` to call back when complete
+     */
+    void async_shutdown(shutdown_handler handler) {
+        handler(lib::error_code());
+    }
+private:
+    // member variables!
+    lib::shared_ptr<alog_type> m_alog;
+    lib::shared_ptr<elog_type> m_elog;
+};
+
+
+} // namespace stub
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_STUB_CON_HPP
diff --git a/subprojects/websocketpp/websocketpp/transport/stub/endpoint.hpp b/subprojects/websocketpp/websocketpp/transport/stub/endpoint.hpp
new file mode 100644
index 000000000..3bbb78f35
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/transport/stub/endpoint.hpp
@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_TRANSPORT_STUB_HPP
+#define WEBSOCKETPP_TRANSPORT_STUB_HPP
+
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/logger/levels.hpp>
+
+#include <websocketpp/transport/base/endpoint.hpp>
+#include <websocketpp/transport/stub/connection.hpp>
+
+namespace websocketpp {
+namespace transport {
+namespace stub {
+
+template <typename config>
+class endpoint {
+public:
+    /// Type of this endpoint transport component
+    typedef endpoint type;
+    /// Type of a pointer to this endpoint transport component
+    typedef lib::shared_ptr<type> ptr;
+
+    /// Type of this endpoint's concurrency policy
+    typedef typename config::concurrency_type concurrency_type;
+    /// Type of this endpoint's error logging policy
+    typedef typename config::elog_type elog_type;
+    /// Type of this endpoint's access logging policy
+    typedef typename config::alog_type alog_type;
+
+    /// Type of this endpoint transport component's associated connection
+    /// transport component.
+    typedef stub::connection<config> transport_con_type;
+    /// Type of a shared pointer to this endpoint transport component's
+    /// associated connection transport component
+    typedef typename transport_con_type::ptr transport_con_ptr;
+
+    // generate and manage our own io_service
+    explicit endpoint()
+    {
+        //std::cout << "transport::iostream::endpoint constructor" << std::endl;
+    }
+
+    /// Set whether or not endpoint can create secure connections
+    /**
+     * TODO: docs
+     *
+     * Setting this value only indicates whether or not the endpoint is capable
+     * of producing and managing secure connections. Connections produced by
+     * this endpoint must also be individually flagged as secure if they are.
+     *
+     * @since 0.3.0-alpha4
+     *
+     * @param value Whether or not the endpoint can create secure connections.
+     */
+    void set_secure(bool value) {}
+
+    /// Tests whether or not the underlying transport is secure
+    /**
+     * TODO: docs
+     *
+     * @return Whether or not the underlying transport is secure
+     */
+    bool is_secure() const {
+        return false;
+    }
+protected:
+    /// Initialize logging
+    /**
+     * The loggers are located in the main endpoint class. As such, the
+     * transport doesn't have direct access to them. This method is called
+     * by the endpoint constructor to allow shared logging from the transport
+     * component. These are raw pointers to member variables of the endpoint.
+     * In particular, they cannot be used in the transport constructor as they
+     * haven't been constructed yet, and cannot be used in the transport
+     * destructor as they will have been destroyed by then.
+     *
+     * @param a A pointer to the access logger to use.
+     * @param e A pointer to the error logger to use.
+     */
+    void init_logging(alog_type * a, elog_type * e) {}
+
+    /// Initiate a new connection
+    /**
+     * @param tcon A pointer to the transport connection component of the
+     * connection to connect.
+     * @param u A URI pointer to the URI to connect to.
+     * @param cb The function to call back with the results when complete.
+     */
+    void async_connect(transport_con_ptr tcon, uri_ptr u, connect_handler cb) {
+        cb(make_error_code(error::not_implemented));
+    }
+
+    /// Initialize a connection
+    /**
+     * Init is called by an endpoint once for each newly created connection.
+     * It's purpose is to give the transport policy the chance to perform any
+     * transport specific initialization that couldn't be done via the default
+     * constructor.
+     *
+     * @param tcon A pointer to the transport portion of the connection.
+     * @return A status code indicating the success or failure of the operation
+     */
+    lib::error_code init(transport_con_ptr tcon) {
+        return make_error_code(error::not_implemented);
+    }
+private:
+
+};
+
+} // namespace stub
+} // namespace transport
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_TRANSPORT_STUB_HPP
diff --git a/subprojects/websocketpp/websocketpp/uri.hpp b/subprojects/websocketpp/websocketpp/uri.hpp
new file mode 100644
index 000000000..c0b8b0cbd
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/uri.hpp
@@ -0,0 +1,356 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_URI_HPP
+#define WEBSOCKETPP_URI_HPP
+
+#include <websocketpp/error.hpp>
+
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/common/stdint.hpp>
+
+#include <algorithm>
+#include <sstream>
+#include <string>
+
+namespace websocketpp {
+
+// TODO: figure out why this fixes horrible linking errors.
+
+/// Default port for ws://
+static uint16_t const uri_default_port = 80;
+/// Default port for wss://
+static uint16_t const uri_default_secure_port = 443;
+
+class uri {
+public:
+    explicit uri(std::string const & uri_string) : m_valid(false) {
+        std::string::const_iterator it;
+        std::string::const_iterator temp;
+
+        int state = 0;
+
+        it = uri_string.begin();
+        size_t uri_len = uri_string.length();
+
+        if (uri_len >= 7 && std::equal(it,it+6,"wss://")) {
+            m_secure = true;
+            m_scheme = "wss";
+            it += 6;
+        } else if (uri_len >= 6 && std::equal(it,it+5,"ws://")) {
+            m_secure = false;
+            m_scheme = "ws";
+            it += 5;
+        } else if (uri_len >= 8 && std::equal(it,it+7,"http://")) {
+            m_secure = false;
+            m_scheme = "http";
+            it += 7;
+        } else if (uri_len >= 9 && std::equal(it,it+8,"https://")) {
+            m_secure = true;
+            m_scheme = "https";
+            it += 8;
+        } else {
+            return;
+        }
+
+        // extract host.
+        // either a host string
+        // an IPv4 address
+        // or an IPv6 address
+        if (*it == '[') {
+            ++it;
+            // IPv6 literal
+            // extract IPv6 digits until ]
+
+            // TODO: this doesn't work on g++... not sure why
+            //temp = std::find(it,it2,']');
+
+            temp = it;
+            while (temp != uri_string.end()) {
+                if (*temp == ']') {
+                    break;
+                }
+                ++temp;
+            }
+
+            if (temp == uri_string.end()) {
+                return;
+            } else {
+                // validate IPv6 literal parts
+                // can contain numbers, a-f and A-F
+                m_host.append(it,temp);
+            }
+            it = temp+1;
+            if (it == uri_string.end()) {
+                state = 2;
+            } else if (*it == '/') {
+                state = 2;
+                ++it;
+            } else if (*it == ':') {
+                state = 1;
+                ++it;
+            } else {
+                // problem
+                return;
+            }
+        } else {
+            // IPv4 or hostname
+            // extract until : or /
+            while (state == 0) {
+                if (it == uri_string.end()) {
+                    state = 2;
+                    break;
+                } else if (*it == '/') {
+                    state = 2;
+                } else if (*it == ':') {
+                    // end hostname start port
+                    state = 1;
+                } else {
+                    m_host += *it;
+                }
+                ++it;
+            }
+        }
+
+        // parse port
+        std::string port;
+        while (state == 1) {
+            if (it == uri_string.end()) {
+                // state is not used after this point presently.
+                // this should be re-enabled if it ever is needed in a future
+                // refactoring
+                //state = 3;
+                break;
+            } else if (*it == '/') {
+                state = 3;
+            } else {
+                port += *it;
+            }
+            ++it;
+        }
+
+        lib::error_code ec;
+        m_port = get_port_from_string(port, ec);
+
+        if (ec) {
+            return;
+        }
+
+        m_resource = "/";
+        m_resource.append(it,uri_string.end());
+
+
+        m_valid = true;
+    }
+
+    uri(bool secure, std::string const & host, uint16_t port,
+        std::string const & resource)
+      : m_scheme(secure ? "wss" : "ws")
+      , m_host(host)
+      , m_resource(resource.empty() ? "/" : resource)
+      , m_port(port)
+      , m_secure(secure)
+      , m_valid(true) {}
+
+    uri(bool secure, std::string const & host, std::string const & resource)
+      : m_scheme(secure ? "wss" : "ws")
+      , m_host(host)
+      , m_resource(resource.empty() ? "/" : resource)
+      , m_port(secure ? uri_default_secure_port : uri_default_port)
+      , m_secure(secure)
+      , m_valid(true) {}
+
+    uri(bool secure, std::string const & host, std::string const & port,
+        std::string const & resource)
+      : m_scheme(secure ? "wss" : "ws")
+      , m_host(host)
+      , m_resource(resource.empty() ? "/" : resource)
+      , m_secure(secure)
+    {
+        lib::error_code ec;
+        m_port = get_port_from_string(port,ec);
+        m_valid = !ec;
+    }
+
+    uri(std::string const & scheme, std::string const & host, uint16_t port,
+        std::string const & resource)
+      : m_scheme(scheme)
+      , m_host(host)
+      , m_resource(resource.empty() ? "/" : resource)
+      , m_port(port)
+      , m_secure(scheme == "wss" || scheme == "https")
+      , m_valid(true) {}
+
+    uri(std::string scheme, std::string const & host, std::string const & resource)
+      : m_scheme(scheme)
+      , m_host(host)
+      , m_resource(resource.empty() ? "/" : resource)
+      , m_port((scheme == "wss" || scheme == "https") ? uri_default_secure_port : uri_default_port)
+      , m_secure(scheme == "wss" || scheme == "https")
+      , m_valid(true) {}
+
+    uri(std::string const & scheme, std::string const & host,
+        std::string const & port, std::string const & resource)
+      : m_scheme(scheme)
+      , m_host(host)
+      , m_resource(resource.empty() ? "/" : resource)
+      , m_secure(scheme == "wss" || scheme == "https")
+    {
+        lib::error_code ec;
+        m_port = get_port_from_string(port,ec);
+        m_valid = !ec;
+    }
+
+    bool get_valid() const {
+        return m_valid;
+    }
+
+    bool get_secure() const {
+        return m_secure;
+    }
+
+    std::string const & get_scheme() const {
+        return m_scheme;
+    }
+
+    std::string const & get_host() const {
+        return m_host;
+    }
+
+    std::string get_host_port() const {
+        if (m_port == (m_secure ? uri_default_secure_port : uri_default_port)) {
+            return m_host;
+        } else {
+            std::stringstream p;
+            p << m_host << ":" << m_port;
+            return p.str();
+        }
+    }
+
+    std::string get_authority() const {
+        std::stringstream p;
+        p << m_host << ":" << m_port;
+        return p.str();
+    }
+
+    uint16_t get_port() const {
+        return m_port;
+    }
+
+    std::string get_port_str() const {
+        std::stringstream p;
+        p << m_port;
+        return p.str();
+    }
+
+    std::string const & get_resource() const {
+        return m_resource;
+    }
+
+    std::string str() const {
+        std::stringstream s;
+
+        s << m_scheme << "://" << m_host;
+
+        if (m_port != (m_secure ? uri_default_secure_port : uri_default_port)) {
+            s << ":" << m_port;
+        }
+
+        s << m_resource;
+        return s.str();
+    }
+
+    /// Return the query portion
+    /**
+     * Returns the query portion (after the ?) of the URI or an empty string if
+     * there is none.
+     *
+     * @return query portion of the URI.
+     */
+    std::string get_query() const {
+        std::size_t found = m_resource.find('?');
+        if (found != std::string::npos) {
+            return m_resource.substr(found + 1);
+        } else {
+            return "";
+        }
+    }
+
+    // get fragment
+
+    // hi <3
+
+    // get the string representation of this URI
+
+    //std::string base() const; // is this still needed?
+
+    // setter methods set some or all (in the case of parse) based on the input.
+    // These functions throw a uri_exception on failure.
+    /*void set_uri(const std::string& uri);
+
+    void set_secure(bool secure);
+    void set_host(const std::string& host);
+    void set_port(uint16_t port);
+    void set_port(const std::string& port);
+    void set_resource(const std::string& resource);*/
+private:
+    uint16_t get_port_from_string(std::string const & port, lib::error_code &
+        ec) const
+    {
+        ec = lib::error_code();
+
+        if (port.empty()) {
+            return (m_secure ? uri_default_secure_port : uri_default_port);
+        }
+
+        unsigned int t_port = static_cast<unsigned int>(atoi(port.c_str()));
+
+        if (t_port > 65535) {
+            ec = error::make_error_code(error::invalid_port);
+        }
+
+        if (t_port == 0) {
+            ec = error::make_error_code(error::invalid_port);
+        }
+
+        return static_cast<uint16_t>(t_port);
+    }
+
+    std::string m_scheme;
+    std::string m_host;
+    std::string m_resource;
+    uint16_t    m_port;
+    bool        m_secure;
+    bool        m_valid;
+};
+
+/// Pointer to a URI
+typedef lib::shared_ptr<uri> uri_ptr;
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_URI_HPP
diff --git a/subprojects/websocketpp/websocketpp/utf8_validator.hpp b/subprojects/websocketpp/websocketpp/utf8_validator.hpp
new file mode 100644
index 000000000..c057da629
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/utf8_validator.hpp
@@ -0,0 +1,154 @@
+/*
+ * The following code is adapted from code originally written by Bjoern
+ * Hoehrmann <bjoern@hoehrmann.de>. See
+ * http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for details.
+ *
+ * The original license:
+ *
+ * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+*/
+
+#ifndef UTF8_VALIDATOR_HPP
+#define UTF8_VALIDATOR_HPP
+
+#include <websocketpp/common/stdint.hpp>
+
+#include <string>
+
+namespace websocketpp {
+namespace utf8_validator {
+
+/// State that represents a valid utf8 input sequence
+static unsigned int const utf8_accept = 0;
+/// State that represents an invalid utf8 input sequence
+static unsigned int const utf8_reject = 1;
+
+/// Lookup table for the UTF8 decode state machine
+static uint8_t const utf8d[] = {
+  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 00..1f
+  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 20..3f
+  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 40..5f
+  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 60..7f
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, // 80..9f
+  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, // a0..bf
+  8,8,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // c0..df
+  0xa,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x4,0x3,0x3, // e0..ef
+  0xb,0x6,0x6,0x6,0x5,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8, // f0..ff
+  0x0,0x1,0x2,0x3,0x5,0x8,0x7,0x1,0x1,0x1,0x4,0x6,0x1,0x1,0x1,0x1, // s0..s0
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1, // s1..s2
+  1,2,1,1,1,1,1,2,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1, // s3..s4
+  1,2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,3,1,1,1,1,1,1, // s5..s6
+  1,3,1,1,1,1,1,3,1,3,1,1,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // s7..s8
+};
+
+/// Decode the next byte of a UTF8 sequence
+/**
+ * @param [out] state The decoder state to advance
+ * @param [out] codep The codepoint to fill in
+ * @param [in] byte The byte to input
+ * @return The ending state of the decode operation
+ */
+inline uint32_t decode(uint32_t * state, uint32_t * codep, uint8_t byte) {
+  uint32_t type = utf8d[byte];
+
+  *codep = (*state != utf8_accept) ?
+    (byte & 0x3fu) | (*codep << 6) :
+    (0xff >> type) & (byte);
+
+  *state = utf8d[256 + *state*16 + type];
+  return *state;
+}
+
+/// Provides streaming UTF8 validation functionality
+class validator {
+public:
+    /// Construct and initialize the validator
+    validator() : m_state(utf8_accept),m_codepoint(0) {}
+
+    /// Advance the state of the validator with the next input byte
+    /**
+     * @param byte The byte to advance the validation state with
+     * @return Whether or not the byte resulted in a validation error.
+     */
+    bool consume (uint8_t byte) {
+        if (utf8_validator::decode(&m_state,&m_codepoint,byte) == utf8_reject) {
+            return false;
+        }
+        return true;
+    }
+
+    /// Advance validator state with input from an iterator pair
+    /**
+     * @param begin Input iterator to the start of the input range
+     * @param end Input iterator to the end of the input range
+     * @return Whether or not decoding the bytes resulted in a validation error.
+     */
+    template <typename iterator_type>
+    bool decode (iterator_type begin, iterator_type end) {
+        for (iterator_type it = begin; it != end; ++it) {
+            unsigned int result = utf8_validator::decode(
+                &m_state,
+                &m_codepoint,
+                static_cast<uint8_t>(*it)
+            );
+
+            if (result == utf8_reject) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /// Return whether the input sequence ended on a valid utf8 codepoint
+    /**
+     * @return Whether or not the input sequence ended on a valid codepoint.
+     */
+    bool complete() {
+        return m_state == utf8_accept;
+    }
+
+    /// Reset the validator to decode another message
+    void reset() {
+        m_state = utf8_accept;
+        m_codepoint = 0;
+    }
+private:
+    uint32_t    m_state;
+    uint32_t    m_codepoint;
+};
+
+/// Validate a UTF8 string
+/**
+ * convenience function that creates a validator, validates a complete string
+ * and returns the result.
+ */
+inline bool validate(std::string const & s) {
+    validator v;
+    if (!v.decode(s.begin(),s.end())) {
+        return false;
+    }
+    return v.complete();
+}
+
+} // namespace utf8_validator
+} // namespace websocketpp
+
+#endif // UTF8_VALIDATOR_HPP
diff --git a/subprojects/websocketpp/websocketpp/utilities.hpp b/subprojects/websocketpp/websocketpp/utilities.hpp
new file mode 100644
index 000000000..b983c9f3a
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/utilities.hpp
@@ -0,0 +1,180 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_UTILITIES_HPP
+#define WEBSOCKETPP_UTILITIES_HPP
+
+#include <websocketpp/common/stdint.hpp>
+
+#include <algorithm>
+#include <string>
+#include <locale>
+
+namespace websocketpp {
+/// Generic non-websocket specific utility functions and data structures
+namespace utility {
+
+/// Helper functor for case insensitive find
+/**
+ * Based on code from
+ * http://stackoverflow.com/questions/3152241/case-insensitive-stdstring-find
+ *
+ * templated version of my_equal so it could work with both char and wchar_t
+ */
+template<typename charT>
+struct my_equal {
+    /// Construct the functor with the given locale
+    /**
+     * @param [in] loc The locale to use for determining the case of values
+     */
+    my_equal(std::locale const & loc ) : m_loc(loc) {}
+
+    /// Perform a case insensitive comparison
+    /**
+     * @param ch1 The first value to compare
+     * @param ch2 The second value to compare
+     * @return Whether or not the two values are equal when both are converted
+     *         to uppercase using the given locale.
+     */
+    bool operator()(charT ch1, charT ch2) {
+        return std::toupper(ch1, m_loc) == std::toupper(ch2, m_loc);
+    }
+private:
+    std::locale const & m_loc;
+};
+
+/// Helper less than functor for case insensitive find
+/**
+ * Based on code from
+ * http://stackoverflow.com/questions/3152241/case-insensitive-stdstring-find
+ */
+struct ci_less {
+    // case-independent (ci) compare_less binary function
+    struct nocase_compare {
+        bool operator() (unsigned char const & c1, unsigned char const & c2) const {
+            return tolower (c1) < tolower (c2);
+        }
+    };
+    bool operator() (std::string const & s1, std::string const & s2) const {
+        return std::lexicographical_compare
+            (s1.begin (), s1.end (),   // source range
+            s2.begin (), s2.end (),   // dest range
+            nocase_compare ());  // comparison
+    }
+};
+
+/// Find substring (case insensitive)
+/**
+ * @param [in] haystack The string to search in
+ * @param [in] needle The string to search for
+ * @param [in] loc The locale to use for determining the case of values.
+ *             Defaults to the current locale.
+ * @return An iterator to the first element of the first occurrance of needle in
+ *         haystack. If the sequence is not found, the function returns
+ *         haystack.end()
+ */
+template<typename T>
+typename T::const_iterator ci_find_substr(T const & haystack, T const & needle,
+    std::locale const & loc = std::locale())
+{
+    return std::search( haystack.begin(), haystack.end(),
+        needle.begin(), needle.end(), my_equal<typename T::value_type>(loc) );
+}
+
+/// Find substring (case insensitive)
+/**
+ * @todo Is this still used? This method may not make sense.. should use
+ * iterators or be less generic. As is it is too tightly coupled to std::string
+ *
+ * @param [in] haystack The string to search in
+ * @param [in] needle The string to search for as a char array of values
+ * @param [in] size Length of needle
+ * @param [in] loc The locale to use for determining the case of values.
+ *             Defaults to the current locale.
+ * @return An iterator to the first element of the first occurrance of needle in
+ *         haystack. If the sequence is not found, the function returns
+ *         haystack.end()
+ */
+template<typename T>
+typename T::const_iterator ci_find_substr(T const & haystack,
+    typename T::value_type const * needle, typename T::size_type size,
+    std::locale const & loc = std::locale())
+{
+    return std::search( haystack.begin(), haystack.end(),
+        needle, needle+size, my_equal<typename T::value_type>(loc) );
+}
+
+/// Convert a string to lowercase
+/**
+ * @param [in] in The string to convert
+ * @return The converted string
+ */
+std::string to_lower(std::string const & in);
+
+/// Replace all occurrances of a substring with another
+/**
+ * @param [in] subject The string to search in
+ * @param [in] search The string to search for
+ * @param [in] replace The string to replace with
+ * @return A copy of `subject` with all occurances of `search` replaced with
+ *         `replace`
+ */
+std::string string_replace_all(std::string subject, std::string const & search,
+                               std::string const & replace);
+
+/// Convert std::string to ascii printed string of hex digits
+/**
+ * @param [in] input The string to print
+ * @return A copy of `input` converted to the printable representation of the
+ *         hex values of its data.
+ */
+std::string to_hex(std::string const & input);
+
+/// Convert byte array (uint8_t) to ascii printed string of hex digits
+/**
+ * @param [in] input The byte array to print
+ * @param [in] length The length of input
+ * @return A copy of `input` converted to the printable representation of the
+ *         hex values of its data.
+ */
+std::string to_hex(uint8_t const * input, size_t length);
+
+/// Convert char array to ascii printed string of hex digits
+/**
+ * @param [in] input The char array to print
+ * @param [in] length The length of input
+ * @return A copy of `input` converted to the printable representation of the
+ *         hex values of its data.
+ */
+std::string to_hex(char const * input, size_t length);
+
+} // namespace utility
+} // namespace websocketpp
+
+#include <websocketpp/impl/utilities_impl.hpp>
+
+#endif // WEBSOCKETPP_UTILITIES_HPP
diff --git a/subprojects/websocketpp/websocketpp/version.hpp b/subprojects/websocketpp/websocketpp/version.hpp
new file mode 100644
index 000000000..f701ab103
--- /dev/null
+++ b/subprojects/websocketpp/websocketpp/version.hpp
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the WebSocket++ Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef WEBSOCKETPP_VERSION_HPP
+#define WEBSOCKETPP_VERSION_HPP
+
+/// Namespace for the WebSocket++ project
+namespace websocketpp {
+
+/*
+ other places where version information is kept
+ - readme.md
+ - changelog.md
+ - Doxyfile
+ - CMakeLists.txt
+*/
+
+/// Library major version number
+static int const major_version = 0;
+/// Library minor version number
+static int const minor_version = 8;
+/// Library patch version number
+static int const patch_version = 1;
+/// Library pre-release flag
+/**
+ * This is a textual flag indicating the type and number for pre-release
+ * versions (dev, alpha, beta, rc). This will be blank for release versions.
+ */
+
+static char const prerelease_flag[] = "";
+
+/// Default user agent string
+static char const user_agent[] = "WebSocket++/0.8.1";
+
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_VERSION_HPP
diff --git a/subprojects/wswrap b/subprojects/wswrap
new file mode 160000
index 000000000..47438193e
--- /dev/null
+++ b/subprojects/wswrap
@@ -0,0 +1 @@
+Subproject commit 47438193ec50427ee28aadf294ba57baefd9f3f1