default void notifyLeaderChanged(ConsensusGroupId groupId, int newLeaderId) {
      // do nothing default
    }
Notify the {@link IStateMachine} that a new leader has been elected. Note that the new leader
can possibly be this server.

@param groupId The id of this consensus group.
@param newLeaderId The id of the new leader node.
iotdb-core/consensus/src/main/java/org/apache/iotdb/consensus/IStateMachine.java