Github user dyanarose commented on the issue:
https://github.com/apache/flink/pull/5295
Ah, I hadn't thought to keep both in place. So unless the Dynamic
SessionWindow classes had withDynamicGap made package private, you would then
be able to instantiate them from two different classes. That could feel a bit
iffy, however someone else would call it a convenience method.
I'll get the change in for the Trigger cast, that should clean up the PR a
fair bit---
