anchor.diff:  /// [pluginClass] will be the entry point to the plugin's native code.
   class MacOSPlugin extends PluginPlatform implements NativeOrDartPlugin {
     const MacOSPlugin({
  -    @required this.name,
  +    required this.name,
       this.pluginClass,
       this.dartPluginClass,
     });
  
positive.code: /// [pluginClass] will be the entry point to the plugin's native code.
  class WindowsPlugin extends PluginPlatform implements NativeOrDartPlugin{
    const WindowsPlugin({
      @required this.name,
      this.pluginClass,
      this.dartPluginClass,
    }) : assert(pluginClass != null || dartPluginClass != null);
  
negative.code:       )
      ];
  
      File? mainPluginClass;
      bool mainClassFound = false;
      for (final String mainClassCandidate in mainClassCandidates) {
        mainPluginClass = _fileSystem.file(mainClassCandidate);
  