anchor.diff:      this.animation,
       this.fit,
       this.alignment,
  +    this.placeHolder,
     }) : src = _Source.asset;
   
     const RiveAnimation.network(
  
positive.code:     this.animation,
      this.fit,
      this.alignment,
    }) : src = _Source.network;
  
    @override
  
negative.code:   final String? animation;
    final BoxFit? fit;
    final Alignment? alignment;
    /// Widget displayed while the rive is loading.
    final Widget? placeHolder;
  
    /// Creates a new RiveAnimation from an asset bundle
    const RiveAnimation.asset(
  