docs: public static InputStream getRequestInputStream(ExternalContext ec)
              throws IOException
      {
          RequestType type = getRequestType(ec);
          if (type.isRequestFromClient())
          {
              Object req = ec.getRequest();
              if (type.isPortlet())
              {
                  return (InputStream) _runMethod(req, "getPortletInputStream");
              }
              else
              {
                  return ((ServletRequest) ec.getRequest()).getInputStream();
              }
          }
  
          return null;
      }