public void setBitmap(@Nullable Bitmap bitmap) {
    this.bitmap = bitmap;
  }
Permanently sets the bitmap on this LottieImageAsset. This will:
1) Overwrite any existing Bitmaps.
2) Apply to *all* animations that use this LottieComposition.

If you only want to replace the bitmap for this animation, use dynamic properties
with {@link LottieProperty#IMAGE}.
lottie/src/main/java/com/airbnb/lottie/LottieImageAsset.java