@Override
  public boolean isLeaderReady(ConsensusGroupId groupId) {
    return true;
  }
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