Since the core changes in the cancelation process where now cancellationTokens are observed rather than a thread.abort attempt, the expected exception is now OperationCanceledException when calling .Abort on the controller.
Also eliminated the time based awaiting to abort in favor of monitoring the backup phase to ensure the .Abort happens after the controller has had time to initiate the backend and backend is at Backup_ProcessingFiles state.
Marcelo C.
64d40ef0ea