docs: private void enhanceFAB(final FloatingActionButton fab, int dx, int dy) {
          if (isEnhancedFAB() && getFab() != null) {
              final FloatingActionButton mFloatingActionButton = this.fab;
              if (getLinearLayoutManager() != null) {
                  if (dy > 0) {
                      if (mFloatingActionButton.getVisibility() == View.VISIBLE) {
                          mFloatingActionButton.hide();
                      }
                  } else {
                      if (mFloatingActionButton.getVisibility() != View.VISIBLE) {
                          mFloatingActionButton.show();
                      }
                  }
              }
          }
      }