anchor.diff:  
     @override
     Future<List<DiagramMetadata>> get diagrams async => <DiagramMetadata>[
  -    const CustomListItemDiagram('custom_list_item'),
  -  ];
  +        const CustomListItemDiagram('custom_list_item'),
  +      ];
   
     @override
     Future<File> generateDiagram(DiagramMetadata diagram) async {
  
positive.code:             CustomListItem(
                user: 'Flutter',
                viewCount: 999000,
                thumbnail: Icon(Icons.videocam, size: 80, color: Colors.blueGrey),
                title: 'The Flutter YouTube Channel',
              ),
              CustomListItem(
                user: 'Dash',
                viewCount: 884000,
                thumbnail: Icon(Icons.flight_takeoff, size: 80, color: Colors.blueGrey),
                title: 'Announcing Flutter 1.0',
              ),
            ],
  
negative.code:             ),
              flex: 3,
            ),
            const Icon(
              Icons.more_vert,
              size: 16.0,
            ),
          ],
        ),
      );
  