More straightforward way to provide end metadata for interactions?

[pyricau]

Currently there's an interaction object that can be updated, that works but not convenient as it has to be created early, so the end metadata is typically a lateinit var, which you might forget. We want to make sure we don't forget to provide the data as we call finish.

[pyricau]

One possible way to help is to include the start and end event with the running / finishing / interaction and the result.

But that doesn't quite work for the case where we want to serialize something from the interaction instead. Might have to play with that on the consuming side though.