EventProcessor should not exist

[tokatoka]

We are trying to add EM, Z to the executors here #2873, which I think is a correct thing
Now the problem is that we have this code.

impl<E, EMH, I, S, SHM, SP, Z> EventProcessor<E, S, Z>
    for LlmpRestartingEventManager<EMH, I, S, SHM, SP>
where
    E: HasObservers,
    E::Observers: DeserializeOwned,
    EMH: EventManagerHooksTuple<I, S>,
    I: DeserializeOwned + Input,
    S: HasImported + HasCurrentTestcase<I> + HasSolutions<I> + Stoppable + Serialize,
    SHM: ShMem,
    SP: ShMemProvider<ShMem = SHM>,
    Z: ExecutionProcessor<Self, I, E::Observers, S> + EvaluatorObservers<E, Self, I, S>,

and this
Z: ExecutionProcessor<Self, I, E::Observers, S> + EvaluatorObservers<E, Self, I, S>, is not letting me to compile things, if, for example, CentralizedEventManager is used. Because the fuzzer's EM is CentralizedEventManager, but this implementation's Self is LlmpRestartingEventManager so it won't compile.

To me the biggest problem here is that EventProcessor defined on event manager. I think we should make this a public function...
and delete this EventProcessor trait.

[tokatoka]

The problem I see here is that
this code is doing two stuff.

1. receiving testcase from llmp comm channel. this is the job of event manager
2. evaluating the incoming testcase. but this is not the job of event manager

This code is solely called from fuzzer/mod.rs in fuzz_loop
therefore I propose to change this EventProcessor to EventReceiver which only focuses on the first job.
then we can move the 2nd job to fuzzer/mod.rs instead. and somehow redesign the logic of incoming-testcase processing

[tokatoka]

@domenukk
opinion?
I think this is the core of all the problem
not just the problem that the code doesn't compile. but also the bloated trait bounds in event manager module

[domenukk]

Yes the evaluation doesn't have to be part of event manager. Sounds like we might even be able to give the event manager a callback of sorts that does the eval?

A simple public fn might be an issue if someone wants to change the behavior in their own fuzzer