阻塞式线程

 Dim recvBytes(1023) As Byte
            Dim strIPAddress As String = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName).AddressList(0).ToString
            Dim bytes(3) As Byte
            bytes(0) = 255
            bytes(1) = 255
            bytes(2) = 4
            bytes(3) = CmdCode0x47
            clientSocket.Send(bytes, 4, SocketFlags.None)
            Dim lens As Integer = clientSocket.Receive(recvBytes) '阻塞式，直到接受到数据，否则一直在此等待。所以它所获取的结果是一定有值。容易导致假死

 

 

非阻塞：只要发送必有返回，根据所获取的返回值来判断程序的执行顺序。而这个则不一定有值。效率比较高