Comment by neonbrain

Sorry didn't see your message. What I mean is that if you are not getting RST/FIN or any other indication for your closed communication channel, you only left to the mechanism of timeouts to recognize a partitioned/dead/slow worker client. Basically, you've mentioned them yourself ("timeouts, lack of heartbeats, etc" in your post are all forms of timeouts). So you can piggyback on these timeouts or use a smaller timeout configured in the lease, whatever suits your purpose, I guess. This is what I believe Kleppmann referring here to. He's just being generic in his description.