That seems easy enough to work around. Send two acks, one for what you really received and one for what you are pretending you've received. If the data has bee

That seems easy enough to work around. Send two acks, one for what you really received and one for what you are pretending you've received. If the data has been sent but lost, the sender will accept the aggressive ack. If it hasn't been sent yet, it will accept the less aggressive ack. For that matter, if you have some way of knowing the expected transmission rate (even approximately as long as you can resync to reality), you can blindly send a stream of periodic acks with steadily increasing sequence numbers.