anchor.diff:    /// [shouldSort] is a simple way to apply the default sorting rules.
     StringSelectionOptions(List<T> options,
         {ItemRenderer<T> toFilterableString,
  -      StringSuggestionFilter suggestionFilter,
  +      StringSuggestionFilter<T> suggestionFilter,
         ItemRenderer sanitizeString: _stringFormatSuggestion,
         bool shouldSort: false})
         : this.withOptionGroups([new OptionGroup(options)],
  
positive.code: String _stringFormatSuggestion<T>(T value) =>
      '$value'.replaceAll(' ', '').toLowerCase();
  
  typedef StringSuggestionFilter(suggestion, String filterQuery);
  
  /// The class is meant to be used in areas where a selection can be represented
  /// as a string.
  
negative.code: 
    /// Function for filtering a single suggestion/option, defaults to
    /// [filterOption] method.
    StringSuggestionFilter<T> _suggestionFilter;
  
    /// The [ItemRenderer] that sanitizes options and queries before filtering.
    ItemRenderer _sanitizeString;
  