|  | 
Gets the non-blocking mode of the acceptor.
bool non_blocking() const;
            true if the acceptor's synchronous operations will fail
            with asio::error::would_block if they are unable to perform
            the requested operation immediately. If false, synchronous
            operations will block until complete.
          
            The non-blocking mode has no effect on the behaviour of asynchronous
            operations. Asynchronous operations will never fail with the error asio::error::would_block.