@Override
  public boolean isLeaderReady(ConsensusGroupId groupId) {
    RaftGroupId raftGroupId = Utils.fromConsensusGroupIdToRaftGroupId(groupId);
    try {
      return server.get().getDivision(raftGroupId).getInfo().isLeaderReady();
    } catch (IOException exception) {
      // if the read fails, simply return not ready
      logger.info("isLeaderReady request failed with exception: ", exception);
      return false;
    }
  }
NOTICE: transferLeader *does not guarantee* the leader be transferred to newLeader.
iotdb-core/consensus/src/main/java/org/apache/iotdb/consensus/ratis/RatisConsensus.java