code: public void forceRemoveItems() {
          synchronized (locker) {
              for (int j = 0; j < downloadQueue.size() - getMaxLoading(); j++) {
                  QueueHolder tmp = downloadQueue.get(j);
                  if (tmp != null) {
                      tmp.stopLoading();
                      downloadQueue.remove(j);
                  }
              }
          }
      }
docs: 强制移除所有等待下载的item