@Override
  public void transferLeader(ConsensusGroupId groupId, Peer newLeader) throws ConsensusException {
    throw new ConsensusException("SimpleConsensus does not support leader transfer");
  }
A simple consensus implementation, which can be used when replicaNum is 1.

<p>Notice: The stateMachine needs to implement WAL itself to ensure recovery after a restart
iotdb-core/consensus/src/main/java/org/apache/iotdb/consensus/simple/SimpleConsensus.java