anchor.diff:  
   import '../ui/elements.dart';
   import '../ui/flutter_html_shim.dart';
  -import '../utils.dart';
   import 'frame_flame_chart.dart';
   import 'timeline_protocol.dart';
   
  
positive.code:   void update(TimelineEvent event) {
      attribute('hidden', false);
      _duration.text = 'Duration:'
          ' ${microsAsMsText(event.duration)} - '
          '[${event.startTime} - ${event.endTime}]';
    }
  
  
negative.code:     _duration.text = '';
    }
  }
  
  String _microsAsMsText(num micros, {bool includeUnit = true}) {
    return _msAsText(micros / 1000, includeUnit: includeUnit);
  }
  
  String _msAsText(num milliseconds, {bool includeUnit = true}) {
    return '${milliseconds.toStringAsFixed(3)}${includeUnit ? ' ms' : ''}';
  }
  