code: def on_finish(self):
          
          if self.statsd_prefix != statsd.STATSD_PREFIX:
              statsd.set_prefix(self.statsd_prefix)
  
          if hasattr(self, 'request') and self.request:
              if self.statsd_use_hostname:
                  timer_prefix = 'timers.{0}'.format(socket.gethostname())
                  counter_prefix = 'counters.{0}'.format(socket.gethostname())
              else:
                  timer_prefix = 'timers'
                  counter_prefix = 'counters'
  
              statsd.add_timing(timer_prefix,
                                self.__module__,
                                str(self.__class__.__name__),
                                self.request.method,
                                str(self._status_code),
                                value=self.request.request_time() * 1000)
  
              statsd.incr(counter_prefix,
                          self.__module__,
                          self.__class__.__name__,
                          self.request.method,
                          str(self._status_code))
  
          super(RequestMetricsMixin, self).on_finish()
docs: Invoked once the request has been finished. Increments a counter
          created in the format:
  
          .. code::
  
              <PREFIX>.counters.<host>.package[.module].Class.METHOD.STATUS
              sprockets.counters.localhost.tornado.web.RequestHandler.GET.200
  
          Adds a value to a timer in the following format:
  
          .. code::
  
              <PREFIX>.timers.<host>.package[.module].Class.METHOD.STATUS
              sprockets.timers.localhost.tornado.web.RequestHandler.GET.200