@Override
    public void process(WatchedEvent event) {
      if (type == event.getType()) {
        latch.countDown();
      }
    }
See SlotZNode; some tests (and the setup) are c/p-ed or modified from Curator.
llap-client/src/test/org/apache/hadoop/hive/llap/registry/impl/TestSlotZnode.java