feat(crux_time): cancellable timer

[PatrykBuniX]

Hi! I was playing around with the time capability and realised there's no way to clear the pending timer. This PR adds this possibility.

This PR adds TimeId field for relevant requests/responses of crux_time capability. Since we know the id of the timer we are able to clear it using the new time request: TimeRequest::Clear {id: TimeId}. Once core notifies the shell (notify_shell since we don't expect any response to this particular request) with this effect, the shell should fire the initially set timer sooner with a TimeResponse::Cleared instead of TimeResponse::InstantArrived/TimeResponse::DurationElapsed.

I'm open to any suggestions, I'm also aware that this is a breaking change, maybe you guys see a non-breaking solution to this? Otherwise I will just create a custom capability 😉

[charypar]

Looks great, we've had something like that in mind as well, just didn't get around to it. Thank you!

Can I ask what the use for this was that you found?

[PatrykBuniX]

Can I ask what the use for this was that you found?

I was persisting the timer fire date and resuming it upon app reload and of course I didn't want the timer to live forever, hence the need to clear it.

[charypar]

Makes a lot of sense!

We've got an issue in the backlog to think about how we do effect cancellation universally for all effects (#247), but this is good for timer 👍🏻

[PatrykBuniX]

@charypar I don't think the ci failure is related with the changes I made, can you take a look or re-run? 🙏

[charypar]

Yea, that looks like a must_use has been added on Update, which the examples have not been updated for. /cc @StuartHarris

[StuartHarris]

@PatrykBuniX my apologies. I really should have published crux_core as 0.10.0 instead of 0.9.1, although it should be only tests that are affected.

I'll merge it anyway! Thanks for your help with this!