* run ok
* update comments
* send cancle cmd to all tiflash stores
* updated
* log error if sending failed
* update comments
* disable send task when being killed
* update function name
* add test for kill mpp when mocking grpc hang
* update imports
* update comments
* clean go.mod
* updated
* use cancel to avoid goroutine leak, ensure cancellMppTasks being called just once
* update go.mod
* add test for avoiding goroutine leak
* update test
* update test
* remove unnecessary leak test