code: func newEWMARate(alpha float64, interval time.Duration) *ewmaRate {
  	return &ewmaRate{
  		alpha:    alpha,
  		interval: interval,
  	}
  }
docs: // newEWMARate always allocates a new ewmaRate, as this guarantees the atomically
  // accessed int64 will be aligned on ARM.  See prometheus#2666.