anchor.diff:  
       ThemeData themeData = Theme.of(context);
       Color backgroundColor = Material.of(context).color;
  -    Color indicatorColor = themeData.indicatorColor;
  +    Color indicatorColor = config.indicatorColor ?? themeData.indicatorColor;
       if (indicatorColor == backgroundColor) {
         // ThemeData tries to avoid this by having indicatorColor avoid being the
         // primaryColor. However, it's possible that the tab bar is on a
  
positive.code:   TabBar({
      Key key,
      this.labels,
      this.isScrollable: false
    }) : super(key: key, scrollDirection: Axis.horizontal);
  
    /// The labels to display in the tabs.
  
negative.code:   /// and the entire [TabBar] is scrollable. Otherwise each tab gets an equal
    /// share of the available space.
    final bool isScrollable;
  
    /// The color of the line that appears below the selected tab. If this parameter
    /// is null then the value of the Theme's indicatorColor property is used.
    final Color indicatorColor;
  
    /// The color of selected tab labels. Unselected tab labels are rendered
    /// with the same color rendered at 70% opacity. If this parameter is null then
    /// the color of the theme's body2 text color is used.
    final Color labelColor;
  
    double get minimumHeight {
      for (TabLabel label in labels.values) {
  