Github user pvillard31 commented on the issue:
https://github.com/apache/nifi/pull/3182
Hey @ijokarumawak - just had the opportunity to test this on the cluster
where I originally faced the issue. Only properly closing the `FileSystem`
object didn't help. It's is necessary to also have the invalidation mechanism
to prevent NiFi from being unavailable with the BLOCKED threads.---
