docs: private CloseableReference<Bitmap> createRainbowBitmap() {
      final int w = 256;
      final int h = 256;
      mOriginalBitmap = mPlatformBitmapFactory.createBitmap(w, h, Bitmap.Config.ARGB_8888);
  
      final int[] colors = new int[w * h];
      for (int i = 0; i < w; i++) {
        for (int j = 0; j < h; j++) {
          final float hue = 360f * j / (float) w;
          final float saturation = 2f * (h - i) / (float) h;
          final float value = 1;
          colors[i * h + j] = Color.HSVToColor(255, new float[]{hue, saturation, value});
        }
      }
      mOriginalBitmap.get().setPixels(colors, 0, w, 0, 0, w, h);
  
      return mOriginalBitmap;
    }