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Construct an open acceptor.
basic_socket_acceptor( asio::io_service & io_service, const protocol_type & protocol);
This constructor creates an acceptor and automatically opens it.
                  The io_service
                  object that the acceptor will use to dispatch handlers for any
                  asynchronous operations performed on the acceptor.
                
An object specifying protocol parameters to be used.
Thrown on failure.