Hypothetically, yes, I think this is possible to some extent. You would
have to give up all the things that require a KeyedStream, such as timers,
and the RocksDB state backend. And performance would suffer.
As for the question of determining which key groups (and ultimately, which
keys) are
Just for the sake of experimenting and learning. Let's assume that we have a
keyed process function using keyed state and we want to rewrite it using
operator state. The question is, would that be possible to keep the exact
same behaviour? For example, one could use operator union list state and
