anchor.diff:        {Key key,
         this.width,
         this.height,
  +      this.fit = BoxFit.contain,
  +      this.alignment = Alignment.center,
         this.matchTextDirection = false,
         this.allowDrawingOutsideViewBox = false,
         this.placeholderBuilder})
  
positive.code:   /// will take the height of its parent.
    final double height;
  
    /// The [PictureProvider] used to resolve the SVG.
    final PictureProvider pictureProvider;
  
  
negative.code:       Map<String, String> headers,
        this.width,
        this.height,
        this.fit = BoxFit.contain,
        this.alignment = Alignment.center,
        this.matchTextDirection = false,
        this.allowDrawingOutsideViewBox = false,
        this.placeholderBuilder,
  