Better async effect shutdown behavior

[Archmonger]

Description

Asynchronous code is fundamentally tricky to handle, given issues with race conditions and task cancellation. This is significant to us since we currently support asynchronous effects within use_async_effect.

This PR attempts to alleviate some of those concerns by giving asynchronous effect functions a small amount of time (configurable) to finish executing before being forcibly shutdown.

Additionally, this PR refactors use_effect code to be human-readable.

• fix Better Async Effect Cleanup #956

Predecessor PR:

• Create separate use_async_effect hook #1264

Checklist

Please update this checklist as you complete each item:

• Tests have been developed for bug fixes or new functionality.
• The changelog has been updated, if necessary.
• Documentation has been updated, if necessary.
• GitHub Issues closed by this PR have been linked.

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