docs: public static void createHierarchy(ZooKeeper zk) {
          LinkedList<ZKUtil.StringCallback> callbacks = new LinkedList<ZKUtil.StringCallback>();
          for (String node : CoreZK.ZK_HIERARCHY) {
                  ZKUtil.StringCallback cb = new ZKUtil.StringCallback();
                  callbacks.add(cb);
                  zk.create(node, null, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT, cb, null);
          }
          try {
              for (ZKUtil.StringCallback cb : callbacks) {
                  cb.get();
              }
          } catch (Exception e) {
              org.voltdb.VoltDB.crashLocalVoltDB(
                      e.getMessage(), false, e);
          }
      }