anchor.diff:    /// Casts `String` to a `PlaybackState`.
     ///
     /// Returns `PlaybackState.unknown` if no match is found.
  -  static PlaybackState? castStringToPlaybackState(String value) {
  -    switch (value) {
  +  static PlaybackState? castStringToPlaybackState(String? value) {
  +    switch (value) {
  +      case (null):
  +        return null;
         case ('buffering'):
           return PlaybackState.buffering;
         case ('error'):
  
positive.code:   /// Casts `String` to a `VideoDynamicRange`.
    ///
    /// Returns `VideoDynamicRange.unknown` if no match is found.
    static VideoDynamicRange? castStringToVideoDynamicRange(String value) {
      switch (value) {
        case ('hdr'):
        case ('HDR'):
          return VideoDynamicRange.hdr;
  
negative.code:   /// Casts `String` to a `MediaType`.
    ///
    /// Returns `MediaType.unknown` if no match is found.
    static MediaType? castStringToMediaType(String? value) {
      switch (value) {
        case (null):
          return null;
        case ('album'):
          return MediaType.album;
        case ('clip'):
  