* is called it means either our master has died, or a new one has come up.
* Either way we need to update our knowledge of the master.
* @param event WatchedEvent from ZooKeeper.
*/
public void process(WatchedEvent event) {
EventType type = event.getType();
KeeperState state = event.getState();
LOG.info("Got ZooKeeper event, state: " + state + ", type: " +
type + ", path: " + event.getPath());
// Ignore events if we're shutting down.