@Override
    public Drawable mutate() {
        if (!mutated && super.mutate() == this) {
            state = new BitmapState(state);
            mutated = true;
        }
        return this;
    }
A static {@link GlideDrawable} for displaying a single image.
core/src/main/java/com/bumptech/glide/load/resource/bitmap/GlideBitmapDrawable.java