@Override
    public void handleNewSession(final String sessionId) {
      LOG.info("Handling new session with sessionId=" + sessionId);
      handleNewSession();
    }
After this event, one amongst the following two things could potentially happen:
A. On successful reconnect to another zookeeper server in ensemble, this processor is going to
join the group again as new processor. In this case, retaining buffered events in debounceTimer will be unnecessary.
B. If zookeeper server is unreachable, handleSessionEstablishmentError callback will be triggered indicating
a error scenario. In this case, retaining buffered events in debounceTimer will be unnecessary.
samza-core/src/main/java/org/apache/samza/zk/ZkJobCoordinator.java