There might be some APIs we can use to get more feedback on the state of the connection: packet loss, retransmits, etc. Or even, the jitter itself directly?
Another option (not sure we want to go down that route):icmp ping.
We could then plug the data into the heuristics to better tune the network layer for the actual connection state.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1863