docs: public static Pair<BabySitter, List<String>> blockingFactory(ZooKeeper zk, String dir, Callback cb)
          throws InterruptedException, ExecutionException
      {
          ExecutorService es = CoreUtils.getCachedSingleThreadExecutor("Babysitter-" + dir, 15000);
          Pair<BabySitter, List<String>> babySitter = blockingFactory(zk, dir, cb, es);
          babySitter.getFirst().m_isExecutorServiceLocal = true;
          return babySitter;
      }