@SuppressWarnings("unchecked")
    @Override
    public Resource<GlideDrawable> transcode(Resource<Bitmap> toTranscode) {
        return (Resource<GlideDrawable>) (Resource<? extends GlideDrawable>)
                glideBitmapDrawableTranscoder.transcode(toTranscode);
    }
A wrapper for {@link GlideBitmapDrawableTranscoder} that transcodes
to {@link GlideDrawable} rather than
{@link com.bumptech.glide.load.resource.bitmap.GlideBitmapDrawable}.

TODO: use ? extends GlideDrawable rather than GlideDrawable directly and remove this class.
core/src/main/java/com/bumptech/glide/load/resource/transcode/BitmapToGlideDrawableTranscoder.java