Swift Error GCDAsyncUdpSocketErrorDomain Code=1

Question

现在IOS UDP通信代码如下

 var message = NSData(bytes: send_buf , length: frame_len)
        socket = GCDAsyncUdpSocket(delegate: self, delegateQueue: dispatch_get_main_queue())
        socket.sendData(message, toHost: address, port: port, withTimeout: 10000, tag: 0)
        do {
            //    try socket.enableBroadcast(true)
            try socket.beginReceiving()
        } catch {
            print(error)
        }

打印到的错误如下

 Error Domain=GCDAsyncUdpSocketErrorDomain Code=1 "Must bind socket before you can receive data. You can do this explicitly via bind, or implicitly via connect or by sending data." UserInfo={NSLocalizedDescription=Must bind socket before you can receive data. You can do this explicitly via bind, or implicitly via connect or by sending data.}