@Override
  public void nodeCreated(String path) {
    if (leaderZNode.equals(path) && !candidate.isStopped()) {
      handleLeaderChange();
    }
  }
Handles coordination of a single "leader" instance among many possible candidates. The first
{@link ZKLeaderManager} to successfully create the given znode becomes the leader, allowing the
instance to continue with whatever processing must be protected. Other {@link ZKLeaderManager}
instances will wait to be notified of changes to the leader znode. If the current master instance
fails, the ephemeral leader znode will be removed, and all waiting instances will be notified,
with the race to claim the leader znode beginning all over again.
@deprecated Not used
hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKLeaderManager.java