abstract fun cancel(): Boolean(source)
Attempt to cancel execution of this task.
This attempt will fail if the task has already completed, has already been cancelled, or could not be cancelled for some other reason. If successful, and this task has not started when
cancel is called, this task should never run.
After this method returns, subsequent calls to
#isDone() will always return
true. Subsequent calls to
#isCancelled() will always return
true if this method returned
true if this result transitioned to a cancelled state.