[BUG] loadFailedChild doesn't show error widget

[firebatu]

I use NetworkImage provider to fetch image from the internet. Also I use the Container with placeholder as an argument for loadfailedchild, but in case of an error (Internet connection disabled) placeholder doesn't showing. I just see empty page. I noticed that this happens when using heroAttributes:
Code snippet:

class PhotoViewScreen extends StatelessWidget {
  static const routeName = '/photo-viewer';

  @override
  Widget build(BuildContext context) {
    final Map args = ModalRoute.of(context).settings.arguments as Map;
    return Theme(
      data: ThemeData.dark(),
      child: Scaffold(
        backgroundColor: Colors.black,
        appBar: AppBar(
          backgroundColor: Colors.black,
          actions: [
            IconButton(
              icon: const Icon(CommunityMaterialIcons.dots_vertical),
              onPressed: () {},
            ),
          ],
        ),
        body: Center(
          child: PhotoView(
              heroAttributes: PhotoViewHeroAttributes(tag: args['imageUrl']),
              filterQuality: FilterQuality.high,
              imageProvider: NetworkImage(args['imageUrl']),
              initialScale: PhotoViewComputedScale.contained * 0.9,
              minScale: PhotoViewComputedScale.contained * 0.8,
              maxScale: PhotoViewComputedScale.covered * 1.2,
              basePosition: Alignment.center,
              loadFailedChild: Container(
                height: 200,
                width: double.infinity,
                color: Colors.grey,
                child: const Icon(
                  Icons.error,
                  size: 70,
                  color: Colors.grey,
                ),
              ),
          ),
        ),
      ),
    );
  }
}

[renancaraujo]

Should be fixed on #320

[PerLycke]

@renancaraujo For galleries, there is no errorBuilder option. There's a reason you didn't add errorBuilder for galleries?

const PhotoViewGallery.builder({
    Key key,
    @required this.itemCount,
    @required this.builder,
    this.loadingBuilder,
    this.loadFailedChild,
    this.backgroundDecoration,
    this.gaplessPlayback = false,
    this.reverse = false,
    this.pageController,
    this.onPageChanged,
    this.scaleStateChangedCallback,
    this.enableRotation = false,
    this.scrollPhysics,
    this.scrollDirection = Axis.horizontal,
    this.customSize,
  })  : pageOptions = null,
        assert(itemCount != null),
        assert(builder != null),
        super(key: key);