docs: public static String createActionBlocker(ZooKeeper zk, String node, CreateMode mode, VoltLogger hostLog, String request) {
          //Acquire a lock before creating a blocker and validate actions.
          ZooKeeperLock zklock = new ZooKeeperLock(zk, VoltZK.actionLock, "lock");
          String lockingMessage = null;
          try {
              if(!zklock.acquireLockWithTimeout(TimeUnit.SECONDS.toMillis(60))) {
                  lockingMessage = "Could not acquire a lock to create action blocker:" + request;
              } else {
                  lockingMessage = setActionBlocker(zk, node, mode, hostLog, request);
              }
          } finally {
              try {
                  zklock.releaseLock();
              } catch (IOException e) {}
          }
          return lockingMessage;
      }