flushPostFrameCallbacks method
Drains the post-frame callback queue. Called by the runtime
(native + web) after renderer.renderDiff and by
FleuryTester.pump after layout and paint. Idempotent — a no-op
when no callbacks are queued.
Driven by TuiBinding consumers (run_app, web hosts,
FleuryTester.pump); app code should use addPostFrameCallback.
Implementation
void flushPostFrameCallbacks(Duration timeStamp) {
if (_disposed) return;
tickerScheduler.flushPostFrameCallbacks(timeStamp);
}