docs: def flush(self):
          """ Add accumulator to the moving average queue and reset it. For
          example, called by the StatsCollector once per second to calculate
          per-second average.
          """
          n = self.accumulator
          self.accumulator = 0
  
          stream = self.stream
          stream.append(n)
          self.sum += n
  
          streamlen = len(stream)
  
          if streamlen > self.period:
              self.sum -= stream.popleft()
              streamlen -= 1
  
          if streamlen == 0:
              self.last_average = 0
          else:
              self.last_average = self.sum / streamlen