Github user mattyb149 commented on the issue:
https://github.com/apache/nifi/pull/2667
+1 LGTM, looks like it will work like a barrier sync, the first one in will
relogin if necessary, the rest will no-op, which means there won't be a race
condition / threading issue when some of the threads call doAs. Thanks for the
improvement! Merging to master---
