code: @SuppressWarnings("unused")
      public void addAnimationEndListener(BubbleAnimationEndListener animationEndListener) {
          if (mAnimationEndListeners == null) {
              mAnimationEndListeners = new ArrayList<>();
          }
          mAnimationEndListeners.add(animationEndListener);
      }
docs: Add {@link BubbleAnimationEndListener} which will call when show or hide animation ends
  @param animationEndListener {@link BubbleAnimationEndListener}