Github user StephanEwen commented on the issue:
https://github.com/apache/flink/pull/5962
The comment to make at least one attempt sounds good.
If you refactor this a little bit, you can actually test it. Either make it
a static method to which you pass the timer service, or better, make it a
method `shutdownUninterruptible(Deadline, Logger)` on the TimerService itself.---
