anchor.diff:          const SizedBox(width: denseSpacing),
           Text(description),
         ],
  +    );
  +  }
  +
  +  Widget _buildAverageFps() {
  +    final double sumFrameTimesMs = widget.frames.fold(
  +      0.0,
  +      (sum, frame) =>
  +          sum +
  +          math.max(
  +            1000 / widget.displayRefreshRate,
  +            math.max(frame.uiDurationMs, frame.rasterDurationMs),
  +          ),
  +    );
  +    final avgFrameTime = sumFrameTimesMs / widget.frames.length;
  +    final avgFps = (1 / avgFrameTime * 1000).round();
  +    return Text(
  +      '$avgFps FPS (average)',
  +      maxLines: 2,
       );
     }
   }
  
positive.code:         children: [
            Expanded(child: _buildChart()),
            const SizedBox(width: defaultSpacing),
            _buildChartLegend(),
          ],
        ),
      );
  
negative.code: // Copyright 2019 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  import 'dart:math' as math;
  
  import 'package:flutter/material.dart';
  import 'package:provider/provider.dart';
  