code: protected PortletRenderResult getPortletRenderResult(
              IPortletWindowId portletWindowId,
              HttpServletRequest request,
              HttpServletResponse response)
              throws Exception {
          final IPortletRenderExecutionWorker tracker =
                  getRenderedPortletBodyWorker(portletWindowId, request, response);
          final long timeout = getPortletRenderTimeout(portletWindowId, request);
          return tracker.get(timeout);
      }
docs: Returns the PortletRenderResult waiting up to the portlet's timeout
  
  @return The PortletRenderResult from the portlet's execution
  @throws TimeoutException If the portlet's timeout was hit before a result was returned
  @throws Exception The exception thrown by the portlet during execution