Github user je-ik commented on the issue:
https://github.com/apache/flink/pull/5185
@StephanEwen I think it should be configurable. As Aljoscha pointed out, it
is needed to ensure that these two representations have the same serialized
form in checkpoints, because that way users can switch back and forth the
implementations between application restarts. Unfortunately, I didn't have time
to dive into that so far. :-(---
