thread_pool_http_server crashes with multiple connections

[kenba]

When testing the thread_pool_http_server.cpp example using Apache Benchmark, the HTTP server crashes, e.g.:

ab -n 10000 -c 1000 192.168.1.64:80/hello

or

ab -n 10000 -c 1000 -k 192.168.1.64:80/hello

[kenba]

Revert server.hpp to using an accept_handler without a socket parameter. next_socket_ member variable restored.
next_socket_ now created from next_strand_ when in thread safe mode.

Calls to ASIO::bind_executor removed from connection.hpp to match asio thread pool example HTTP Server 3.

[kenba]

Incorporated in tag 1.11.1.

[kenba]

This problem occurs using boost 1.84.0

[kenba]

This issue is now only observed in Visual Studio debug mode.
The issue does not occur in Visual Studio release mode nor GCC debug or release mode.