code: func NewAvgRateCounter(intrvl time.Duration) *AvgRateCounter {
  	return &AvgRateCounter{
  		hits:     NewRateCounter(intrvl),
  		counter:  NewRateCounter(intrvl),
  		interval: intrvl,
  	}
  }
docs: // NewAvgRateCounter constructs a new AvgRateCounter, for the interval provided