Github user anmolnar commented on the issue:
https://github.com/apache/zookeeper/pull/689
@tumativ I tend to agree with @lvfangmin in adding `interrupt()` call to
shutdown would be the easiest solution here.
In which case I would also add `break;` to the InterruptedException handler
of addDeadWatcher() method.
Out of interest, why WatcherCleaner is not inherited from `ZooKeeperThread`
btw?---
