Considering the changes being made for run()-> Result<>, pump_events, run_ondemand, and addressing inconsistent ordering guarantees for events like MainEventsCleared and RedrawRequested, as well as removing and renaming several core events, then it feels like a similar level of change as happened for EventLoop 2.0.

The details are a bit scattered though, and although some things have been agreed as part of lengthy issue discussions we still need to track those ideas at least as a reminder as to what is left to do.

I'm going to be lite on details here, but a lot of the background discussion probably happened here #2706 and maybe a few other issues we can link back here too.

• Replace run() ->! with run() -> Result as our portable run API available on all platforms (Re-work event loop run APIs: adds run -> Result<>, run_ondemand and pump_events #2767)
• Replace run_return() with pump_events() and run_ondemand() (for Windows, macOS, Linux + Android) (Re-work event loop run APIs: adds run -> Result<>, run_ondemand and pump_events #2767)
• Maybe add run_noreturn() ->! extension API for iOS (discussed in Return immediately from run_app on web #4165)
• Rename LoopDestroyed LoopExiting (Rename LoopDestroyed to LoopExiting #2975)
• Remove RedrawEventsCleared (Remove RedrawEventsCleared + MainEventsCleared, and add AboutToWait #2976)
• Rename MainEventsCleared -> AboutToPoll AboutToWait (Conceptually NewEvents and AboutToWait can be seen as a way to observe the underlying blocking/polling of the event loop - similar to registering an observer with a macOS RunLoop) (Remove RedrawEventsCleared + MainEventsCleared, and add AboutToWait #2976)
• Document that RedrawRequested is no longer guaranteed to be delivered in order with respect to any other event - it is platform specific
• Make it clearer that applications should redraw any time they get a RedrawRequested callback (and they shouldn't defer the redraw outside of the winit callback).
• Make it clearer that Resumed events are delivered on all platforms (not just mobile) and Resumed events are a good place to initialize an application because it's the first point where it's possible to start creating Windows across all platforms.
• Remove lifetime from the Event
• Aim to implement RedrawRequested throttling by default where there's a suitable mechanism provided by the window system
  • By WM_PAINT on Windows
  • Either with drawRect or display link on macOS (same for iOS?) (Implement VSync source (frame pacing) #2412)
  • By frame callbacks on Wayland
  • Via requestAnimationFrame for Web
  • Maybe via Choreographer on Android
  • By praying on X11

I don't mind if we want to collate this information somewhere else, or in a different, better way etc but wanted to a least get a basic task list laid out somewhere

Maybe a milestone would be a nicer way to organize this?