@MainThread
  protected void removeFrameCallback(boolean stopRunning) {
    Choreographer.getInstance().removeFrameCallback(this);
    if (stopRunning) {
      running = false;
    }
  }
Returns the current speed. This will be affected by repeat mode REVERSE.
lottie/src/main/java/com/airbnb/lottie/utils/LottieValueAnimator.java