How to receive concurrent udp socket response?

Question

I want to create a client server UDP socket in c#. I succeed send and receive with single request response.

But I have a problem. When I send for example 5 requests concurrently. the response time of each request is different.

How can I understand each response is for which request ?

Answer 1

 var _connection = new UdpClient( port-to-listen-at );

 IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
 byte[] data = _connection.Receive(ref sender);

When Receive() returns 'sender', it contains sender-info