@WorkerThread
  public static LottieResult<LottieComposition> fromJsonSourceSync(final Source source, @Nullable String cacheKey) {
    return fromJsonSourceSync(source, cacheKey, true);
  }
Return a LottieComposition for the specified raw json string.
If loading from a file, it is preferable to use the InputStream or rawRes version.
lottie/src/main/java/com/airbnb/lottie/LottieCompositionFactory.java