@Nullable
  private static LottieImageAsset findImageAssetForFileName(LottieComposition composition, String fileName) {
    for (LottieImageAsset asset : composition.getImages().values()) {
      if (asset.getFileName().equals(fileName)) {
        return asset;
      }
    }
    return null;
  }
Check if a given InputStream points to a .gzip compressed file
lottie/src/main/java/com/airbnb/lottie/LottieCompositionFactory.java