@Override
  public <T> void addValueCallback(T property, @Nullable LottieValueCallback<T> callback) {
    if (property == LottieProperty.RECTANGLE_SIZE) {
      sizeAnimation.setValueCallback((LottieValueCallback<PointF>) callback);
    } else if (property == LottieProperty.POSITION) {
      positionAnimation.setValueCallback((LottieValueCallback<PointF>) callback);
    } else if (property == LottieProperty.CORNER_RADIUS) {
      cornerRadiusAnimation.setValueCallback((LottieValueCallback<Float>) callback);
    }
  }
This corner radius is from a layer item. The first one is from the roundedness on this specific rect.
lottie/src/main/java/com/airbnb/lottie/animation/content/RectangleContent.java