Can we Flatten `RubyEvent` and `Event` into one?

`RubyEvent` doesn't hold any state that isn't also in `Event`, just from the performance perspective it's only a burden.
I can see about `1.5 * workers * batch_size` `Event` not being GCed at any given time for small batch sizes (up to `256` and a much larger factor than `1.5` for larger batch sizes).
Given that these `RubyEvent`s prevent a ton of `HashMap` from being GCed, I expect a visible improvement in memory use from flattening this out.

Is there any reason not to simply move all the `RubyEvent` methods over to `Event`?
(if we want to cleanly separate the Java interface we could still extract the current public methods from `Event` to an interface that new merged class implements?)