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