anchor.diff:    /// The color of this side of the border.
     final Color color;
   
  -  /// The width of this side of the border, in logical pixels. A
  -  /// zero-width border is a hairline border. To omit the border
  -  /// entirely, set the [style] to [BorderStyle.none].
  +  /// The width of this side of the border, in logical pixels.
  +  ///
  +  /// Setting width to 0.0 will result in a hairline border. This means that
  +  /// the border will have the width of one physical pixel. Also, hairline
  +  /// rendering takes shortcuts when the path overlaps a pixel more than once.
  +  /// This means that it will render faster than otherwise, but it might
  +  /// double-hit pixels, giving it a slightly darker/lighter result.
  +  ///
  +  /// To omit the border entirely, set the [style] to [BorderStyle.none].
     final double width;
   
     /// The style of this side of the border.
  
positive.code: ///
  /// A [Border] consists of four [BorderSide] objects: [Border.top],
  /// [Border.left], [Border.right], and [Border.bottom].
  ///
  /// {@tool sample}
  ///
  
negative.code:   ///
    /// Since a zero width is normally painted as a hairline width rather than no
    /// border at all, the zero factor is special-cased to instead change the
    /// style to [BorderStyle.none].
    ///
    /// Values for `t` are usually obtained from an [Animation<double>], such as
    /// an [AnimationController].
  