Possible design for Evaluator

[rmalmain]

linked to #2897.

we need a new layer between Fuzzer and the other components.
after discussing with @tokatoka, we were thinking of organizing things like this:

• Fuzzer
  • StageTuple -> now contains the ref to the Evaluator to use for the stage
  • EvaluatorTuple
    • Executor
    • Feedback

that way, we can remove Executor contained by some staged (like TracingStage).

[tokatoka]

this is also what @riesentoaster proposed

[riesentoaster]

Yeah, I'd love better separation of concerns between the parts, as discussed in the issue you mentioned.

[tokatoka]

One point that I'm not sure how to implement is that we definitely need to support multiple executors, and thus multiple Evaluators. but the problem is that for each stage, we need to pass the correct Evaluator from the EvaluatorTuple.
i guess it's just matchname and give the stage's the Handle of them

[domenukk]

I'm not 100% seeing what this will look like, but if you all agree I'm on board