anchor.diff:  import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
   
   // To run this test for all demos:
  -// flutter drive --profile --trace-startup -t test_driver/transitions_perf.dart -d <device>
  +//    flutter drive --profile --trace-startup -t test_driver/transitions_perf.dart -d <device>
   // To run this test for just Crane, with scrolling:
  -// flutter drive --profile --trace-startup -t test_driver/transitions_perf.dart -d <device> --dart-define=onlyCrane=true
  -// To run this test for just Reply, with animations:
  -// flutter drive --profile --trace-startup -t test_driver/transitions_perf.dart -d <device> --dart-define=onlyReply=true
  -
  -// Demos for which timeline data will be collected using
  -// FlutterDriver.traceAction().
  -//
  -// Warning: The number of tests executed with timeline collection enabled
  +//    flutter drive --profile --trace-startup -t test_driver/transitions_perf.dart -d <device> --dart-define=onlyCrane=true
  +// To run this test for just Crane, with animations:
  +//    flutter drive --profile --trace-startup -t test_driver/transitions_perf.dart -d <device> --dart-define=onlyReply=true
  +// Enable semantics with the --with_semantics flag
  +// Note: The number of tests executed with timeline collection enabled
   // significantly impacts heap size of the running app. When run with
   // --trace-startup, as we do in this test, the VM stores trace events in an
   // endless buffer instead of a ring buffer.
  +
  +// Demos for which timeline data will be collected using
  +// FlutterDriver.traceAction().
   //
   // These names must match the output of GalleryDemo.describe in
   // lib/data/demos.dart.
  
positive.code:       if (driver != null) {
          await driver.close();
        }
      });
  
      test('only Crane', () async {
  
negative.code:     test('only Reply', () async {
        if (!isTestingReplyOnly) return;
  
        // Collect timeline data for just the Crane study.
        final timeline = await driver.traceAction(
          () async {
            await runDemos(
  