@WorkerThread
  public static LottieResult<LottieComposition> fromJsonSourceSync(final Source source, @Nullable String cacheKey,
      boolean close) {
    return fromJsonReaderSyncInternal(JsonReader.of(buffer(source)), cacheKey, close);
  }
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