docs: @Override
      public final void clear(LayoutManagerHelper helper) {
          // remove LayoutViews if there is one
          if (mLayoutView != null) {
              if (mLayoutViewUnBindListener != null) {
                  mLayoutViewUnBindListener.onUnbind(mLayoutView, this);
              }
              helper.removeChildView(mLayoutView);
              mLayoutView = null;
          }
  
          // call user defined
          onClear(helper);
      }