Hello! Sorry for the long delay.

Would you be able to rebase this forward and fix the merge conflicts? If so, we'd like to review it and see about landing it.

Rebased

Clippy doesn't like methods called default:

error: method `default` can be confused for the standard trait method `std::default::Default::default`
  --> core-foundation/src/runloop.rs:37:5
   |
37 | /     pub fn default() -> CFRunLoopMode<'static> {
38 | |         unsafe { CFRunLoopMode(kCFRunLoopDefaultMode, PhantomData) }
39 | |     }
   | |_____^
   |
   = help: consider implementing the trait `std::default::Default` or choosing a less ambiguous method name
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#should_implement_trait
   = note: `-D clippy::should-implement-trait` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::should_implement_trait)]`

so I renamed the constructors to CFRunLoopMode::default_mode() and CFRunLoopMode::common_modes(). But if you think that's too redundant, we could also ignore the clippy lint.

I think the naming, while redundant, is fine.

Pushed again to fix rustfmt on a line that default_mode pushed over the length limit.

(FYI, there's a GitHub Actions setting for "Require approval for first-time contributors who are new to GitHub" that is less annoying than the default "Require approval for first-time contributors ")