close

Shuts down this node: stops the actor command loop, cancels the leader's election/heartbeat/ quorum-check/lease timer coroutines, and fails every in-flight or still-buffered request (propose/readIndex/changeMembership/transferLeadership and the internal commit-cut) so no caller's await() hangs.

Idempotent. This is not the same as cancelling the owning CoroutineScope: coroutines whose lifecycle is tied directly to the scope — notably the transport-message and snapshot collectors launched at construction — end only when that scope is cancelled. For a full teardown that also releases those, cancel the owning CoroutineScope (which additionally runs the same request-failing cleanup). Call close when you want to retire the node but keep its scope alive.