ios: fix timers

Fixes #4074.
Fixes #3816.

src/changelog/unreleased.md

@@ -228,3 +228,4 @@ changelog entry.
 - On Windows, fixed the event loop not waking on accessibility requests.
 - On X11, fixed cursor grab mode state tracking on error.
 - On X11, fixed crash with uim
+- On iOS, maybe fixed high CPU usage even when using `ControlFlow::Wait`.

src/platform_impl/apple/uikit/app_state.rs

@@ -239,6 +239,7 @@ impl AppState {
             (ControlFlow::Wait, ControlFlow::Wait) => {
                 let start = Instant::now();
                 self.set_state(AppStateImpl::Waiting { start });
+                self.waker.stop()
             },
             (ControlFlow::WaitUntil(old_instant), ControlFlow::WaitUntil(new_instant))
                 if old_instant == new_instant =>