anchor.diff:  
     /// Creates a widget that displays a [PictureStream] obtained from the network.
     ///
  -  /// The `url` argument must not be null.
  -  ///
  -  /// If `width` or `height` are specified, a [SizedBox] will be used to dictate
  -  /// the width and height of the rendered output.  Otherwise, the picture will
  -  /// be sized to its parent.
  +  /// The [url] argument must not be null.
  +  ///
  +  /// Either the [width] and [height] arguments should be specified, or the
  +  /// widget should be placed in a context that sets tight layout constraints.
  +  /// Otherwise, the image dimensions will change as the image is loaded, which
  +  /// will result in ugly layout changes.
     ///
     /// If `matchTextDirection` is set to true, the picture will be flipped
     /// horizontally in [TextDirection.rtl] contexts.
  
positive.code:       Map<String, String> headers,
        this.width,
        this.height,
        this.matchTextDirection = false,
        this.allowDrawingOutsideViewBox = false,
        this.placeholderBuilder,
  
negative.code: /// A widget that will parse SVG data into a [Picture] using a [PictureProvider].
  ///
  /// The picture will be cached using the [PictureCache], incorporating any color
  /// filtering used into the key (meaning the same SVG with two different `color`
  /// arguments applied would be two cache entries).
  class SvgPicture extends StatefulWidget {
    /// The default placeholder for a SVG that may take time to parse or
    /// retrieve, e.g. from a network location.
    static WidgetBuilder defaultPlaceholderBuilder =
        (BuildContext ctx) => const LimitedBox();
  
    /// Instantiates a widget that renders an SVG picture using the `pictureProvider`.
    ///
    /// Either the [width] and [height] arguments should be specified, or the
    /// widget should be placed in a context that sets tight layout constraints.
    /// Otherwise, the image dimensions will change as the image is loaded, which
    /// will result in ugly layout changes.
    ///
    /// If `matchTextDirection` is set to true, the picture will be flipped
    /// horizontally in [TextDirection.rtl] contexts.
  