code: private void notifyAdditionalOnScrolledListener(RecyclerView recyclerView, int dx, int dy) {
          if (mAdditionalOnScrollListener != null) {
              mAdditionalOnScrollListener.onScrolled(recyclerView, dx, dy);
          }
      }
docs: Notifies the OnScrollListener of an onScroll event, since JazzyListView is the primary listener for onScroll events.