LeadershipTransferException
Thrown by RaftNode.transferLeadership when the transfer could not complete.
Two causes:
Timeout: the target did not win an election within one election-timeout window. The old leader resumed normal operation before throwing this exception.
Cancelled: RaftNode.cancelTransfer was called explicitly.
In both cases the old leader is back in its normal operating mode (accepting proposals) when this exception propagates — the caller does not need to do anything to recover.