StreamType represents the transport protocol type used to transfer stream of bytes.

StreamType should meet the AsyncStream concept.

Additionally, it should follow Asio's layered stream model by having a lowest_layer_type member type, and a lowest_layer member function, returing a lowest_layer_type&. The lowest_layer_type should inherit from boost::asio::ip::tcp::socket.

The types boost::asio::ip::tcp::socket, boost::asio::ssl::stream<boost::asio::ip::tcp::socket> and boost::beast::websocket::stream<NextLayer> meet these requirements.