anchor.diff:            fit: widget.fit,
             alignment: widget.alignment,
           )
  -      : const SizedBox();
  +      : widget.placeHolder ?? const SizedBox();
   }
  
positive.code:   final String? animation;
    final BoxFit? fit;
    final Alignment? alignment;
  
    /// Creates a new RiveAnimation from an asset bundle
    const RiveAnimation.asset(
  
negative.code:     this.animation,
      this.fit,
      this.alignment,
      this.placeHolder,
    }) : src = _Source.asset;
  
    const RiveAnimation.network(
  