`DrmDevice` and `UdevBackend` now do not need to be wrapped into `StateToken`s anymore, but can return a separate `SessionObserver` object using the new `AsSessionObserver` trait.
This change was motivated by allowing the `UdevHandle` to obtain a mutable reference to an `EventLoopHandle` to create wayland object, e.g. a `wl_output` object.
Previously this was not possible.
Depends on https://github.com/Smithay/wayland-rs/pull/164
- Add an associated type to the `SessionNotifier` trait for the returned Id's instead of using usize.
- Create a new Id type for the `DirectSessionNotifier`'s implementation, wrapping the previously used usize.
- Derive necessary traits of the new wrapper, make internal value inaccessible and Id's not publically constructable.
Drakulix
Victor Berger