Includes the content of a resource (servlet, JSP page,
HTML file) in the response. In essence, this method enables
programmatic server-side includes.
The included servlet cannot set or change the response status code
or set headers; any attempt to make a change is ignored.
Parameters: request - a RenderRequest object that contains the client request Parameters: response - a RenderResponse object that contains the render response exception: PortletException - if the included resource throws a ServletException, or other exceptions that are not Runtime-or IOExceptions. exception: java.io.IOException - if the included resource throws this exception