Where do you think the callback should come from?
Uhm... soon after the deferred is made?
Typically, you keep a queue of outgoing messages per client.
Once per network tick, you loop through all the clients, and bundle up all the messages for a client into a network packet, and send that.
So it's like we add new bytes of data to the queued message for each loop. It's like we append the new chunk of data to the a list of the message right? I think I understand that concept, but I guess I'm weak at coding it. I'm new to Twisted after all.
Can you please give me an example code? I'm not lazy or what, but that's the way I can understand things better. By learning the code.