private void notifyListenersInternal() {
    // Local reference in case it gets set on a background thread.
    LottieResult<T> result = LottieTask.this.result;
    if (result == null) {
      return;
    }
    if (result.getValue() != null) {
      notifySuccessListeners(result.getValue());
    } else {
      notifyFailureListeners(result.getException());
    }
  }
Remove a given task failure listener. The task will continue to execute so you can re-add
a listener if necessary.

@return the task for call chaining.
lottie/src/main/java/com/airbnb/lottie/LottieTask.java