def no_body( status )
      res.status = ::Rack::Utils.status_code( status )
      res.write ::Rack::Utils::HTTP_STATUS_CODES[ res.status ]
      res['Content-Type' ] = 'text/plain'
    end
def no_body( status )
      res.status = ::Rack::Utils.status_code( status )
      res.write ::Rack::Utils::HTTP_STATUS_CODES[ res.status ]
      res['Content-Type' ] = 'text/plain'
    end
convenient method for status only responses