Add generateTimeline();

[passsy]

Sometimes I want to see the timeline of a successful app. One common way to do this is adding this line at the end of the test (or beginning)

    testWidgets('My test', (tester) async {
      // testCode
      // ...
      timeline.mode = TimelineMode.always;
    });

Instead I'd like to call a method to print me the timeline at any point in the test as it currently is. Similar to takeScreensho().

    testWidgets('My test', (tester) async {
      // testCode
      await generateTimeline();
      // ...
      await generateTimeline();
    });