code: @Override
    public void process(WatchedEvent event) {
      logger.debug("recived event "+ event);
      if (event.getState() == KeeperState.Expired || event.getState() == KeeperState.Disconnected){
        driver.setGoOn(false);
        shutdown();
      }
      if (event.getType() == EventType.NodeDataChanged || event.getType() == EventType.NodeDeleted ) {
        driver.setGoOn(false);
        shutdown();
      }
    }
docs: /*
  We could response to a node change by attempting to modify the driver in the current worker
  however it is cleaner to bring this worker down gracefully, and let it restart elsewhere
  (non-Javadoc)
  @see org.apache.zookeeper.Watcher#process(org.apache.zookeeper.WatchedEvent)