onPeerUnresponsive

Opens (or refreshes) the reconnect window for peerId.

Called by the leader when a peer's link drops. Emits JoinerReconnectEvent.WindowOpened on events.

When a PartitionEvent.PeerUnresponsive feed is available, bridge it here: partitionEvents.collect { if (it is PeerUnresponsive) onPeerUnresponsive(it.peerId, it.at) }.

at is the identity of this partition episode, not just a timestamp. Every JoinerReconnectEvent.WindowOpened emitted for the drop this call reports must echo it unchanged as JoinerReconnectEvent.WindowOpened.detectedAt — including a later re-announcement that extends the same window. See that field for what the caller does with it.