allow eventhandlers and eventspecs for exception handlers

[adhami3310]

No description provided.

[linear]

ENG-5599 Unify generic frontend/backend exception handler API

[codspeed-hq]

CodSpeed Performance Report

Merging #5295 will not alter performance

_{Comparing khaleel/eng-5599-unify-generic-frontendbackend-exception-handler-api (c02e00c) with main (dc9b352)}

Summary

✅ 8 untouched benchmarks

[masenf]

both frontend and backend exception handlers need to be able to be specified as EventSpec/EventHandler

[masenf]

i think we want to avoid the extra round trip to the client for processing this.

is it possible to do something like

await app.event_namespace.on_event(
    sid=self.router.session.session_id,
    data=fix_events(
        events=[frontend_exception_handler(stack)],
        token=self.router.session.client_token,
        router_data=self.router_data,
    )[0],
)

i guess maybe that would have a dead locking issue because the state is already being processed.

[adhami3310]

maybe? i couldn't understand exactly how the flow is going and how to make it do that, which is why i couldn't figure out the backend exception and why this one is a draft