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Is it possible to add a test for this, maybe to https://github.com/flutter/flutter/blob/master/dev/tracing_tests/test/timeline_test.dart?

/cc @chunhtai FYI

Tapping on the green square in the app below exercises the code path that doesn't finish the timeline event and reproduces the problem. The Container widget will have a start event, but no corresponding end event.

@jason-simmons Maybe you can turn this into an integration test similar to how it is done in dev/tracing_tests/test/inflate_widget_tracing_test.dart.

import 'package:flutter/material.dart';

void main() {
  runApp(const MyHomePage());
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final Key globalKey = GlobalKey();
  Key localKey = UniqueKey();

  @override
  Widget build(BuildContext context) {
    return Center(
      key: localKey,
      child: GestureDetector(
        onTap: () {
          setState(() {
            localKey = UniqueKey();
          });
        },
        child: Container(
          color: Colors.green,
          key: globalKey,
          width: 100,
          height: 100,
        ),
      ),
    );
  }
}

Added a test