The crash comes from unhandled exception thrown in ~AsyncStream() destructor, which calls destroyStream() function, which, in turn, calls incorrect version of close() on ASIO socket.

Relevant code piece from async_stream_common.h

....

std::error_code ec;
    stream->shutdown(asio::ip::tcp::socket::shutdown_both, ec);
    stream->close(); // <----- probably meant to call another overload close(ec)
    if (ec) {
        logCloseFailed(ec);
}

....

Most likely another close() overload was meant to be used that accepts ec as an argument. The overload used here just throws an exceptions if socket is closed.