|  | 
Construct an acceptor without opening it.
basic_socket_acceptor( asio::io_service & io_service);
            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.
          
                  The io_service
                  object that the acceptor will use to dispatch handlers for any
                  asynchronous operations performed on the acceptor.