Calling the shutdownNow method of ScheduleMessageService#deliverExecutorService may result in broker inconsistent state.

[XiaoyiPeng]

BUG REPORT

1. Please describe the issue you observed:

   Calling the shutdownNow() method of ScheduleMessageService#deliverExecutorService may lead to broker inconsistent state.

2. Please tell us about your environment:
   Windows 10

3. Other information (e.g. detailed explanation, logs, related issues, suggestions how to fix, etc):

   When the ScheduleMessageService#shutdown() method is called, shutdownNow() method of ScheduleMessageService#deliverExecutorService is called ,which will interrput threads in ScheduleMessageService#deliverExecutorService .

If at this point, the task(eg: ScheduleMessageService#persist() operation) in ScheduleMessageService#deliverExecutorServicehas not completely done, which may lead to broker inconsistent state.

[Git-Yang]

This problem is solved in PR #3478 , you can help review it.

[XiaoyiPeng]

This problem is solved in PR #3478 , you can help review it.

OK, niubility，haha~