Construct an acceptor without opening it.
basic_socket_acceptor( asio::io_service & io_service); basic_socket_acceptor( asio::io_service & io_service, const protocol_type & protocol); basic_socket_acceptor( asio::io_service & io_service, const endpoint_type & endpoint, bool reuse_addr = true); basic_socket_acceptor( asio::io_service & io_service, const protocol_type & protocol, const native_type & native_acceptor);