clear method

void clear()

清空所有注册的任务

Implementation

void clear() {
  _log('[CLEAR] 清空所有注册的任务，当前任务数: ${_registeredTasks.length}');
  _registeredTasks.clear();
  if (_tracker.state == PreloadManagerState.running) {
    cancel();
  }
  _tracker.reset();
  _log('[CLEAR] 清空完成');
}