docs: function mergeUpdates(fiber, state, isForced, callback) {
      let updateQueue = fiber.updateQueue;
      if (isForced) {
          updateQueue.isForced = true; // 如果是true就变不回false
      }
      if (state) {
          updateQueue.pendingStates.push(state);
      }
      if (isFn(callback)) {
          updateQueue.pendingCbs.push(callback);
      }
  }