Refactor Stopping Tasks On Assignment Change of Tasks

[shrinandthakkar]

Only trigger stopping for the tasks that need to be canceled per assignment change in the onAssignmentChange function. This change prevents calling stops on tasks recurrently in case of frequent assignment change triggers.

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[vmaheshw]

Thank you for fixing this.

[surajkn]

So the main objective of the change is to not call stop one more time while a current stop attempt is in progress. Correct?
Is yes I think that is still possible since in "restartDeadTask" we still call "stopUnassignedTasks" which calls "scheduleTasksToStop" with "_tasksPendingStop"

[shrinandthakkar]

So the main objective of the change is to not call stop one more time while a current stop attempt is in progress. Correct? Is yes I think that is still possible since in "restartDeadTask" we still call "stopUnassignedTasks" which calls "scheduleTasksToStop" with "_tasksPendingStop"

@surajkn Actually, the main objective of this change is to separate the two triggers of stopping the tasks. We want to avoid stopping the long-pending tasks whenever onAssignmentChange is invoked. We only want to trigger stop for the running tasks which are not part of the new assignment when the onAssignmentChange is called.

Those long-pending tasks could still be re-triggered for stopping periodically from the restartDeadTask function, which should be the expected behavior I think.