一个定时服务的管理构件，该构件可以通过任务对象添加定时任务，在该任务执行后可以自行删除，该任务未执行时可以删除任务。(A management component of a timed service that adds a timed task through a task object, which can be deleted automatically after execution of the task, and the task can be deleted when it is not executed.)