docs: protected IPortletRenderExecutionWorker startPortletHeaderRenderInternal(
              IPortletWindowId portletWindowId,
              HttpServletRequest request,
              HttpServletResponse response) {
          IPortletRenderExecutionWorker portletHeaderRenderWorker =
                  this.portletWorkerFactory.createRenderHeaderWorker(
                          request, response, portletWindowId);
          portletHeaderRenderWorker.submit();
  
          final Map<IPortletWindowId, IPortletRenderExecutionWorker> portletHeaderRenderingMap =
                  this.getPortletHeaderRenderingMap(request);
          portletHeaderRenderingMap.put(portletWindowId, portletHeaderRenderWorker);
  
          return portletHeaderRenderWorker;
      }