ref: Avoid double-indirection through Arc<Box<T>>

[Swatinem]

This also removes the need to manually box the argument to add_event_processor.

[flub]

Does this still allow you to pass in a Box of a closure if you'd desire so?

[loewenheim]

@flub A quick test on the playground seems to indicate so.

[flub]

@flub A quick test on the playground seems to indicate so.

You forgot the Send + Sync + 'static bounds (especially that last one was what i was concerned about. but yess still works: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=511ce396202ba76002401e6ba278ad08

('d have approved right away, but github has taken that ability away from me)

[Swatinem]

Technically, this is a breaking change, yes! But due to our all-at-once versioning policy, dependency updates (for example tracing-subscriber just now) means we publish semver-breaks all damn time. :-(

But also yes, if you have the proper types, then providing Box<dyn Fn> continues to work. The compiler just needs to know the type, and for some closures, it is not smart enough to infer.