instruments.go
func NewRateScale(d time.Duration) *Rate {
	return &Rate{
		time: time.Now().UnixNano(),
		unit: d.Seconds(),
	}
}
func NewRateScale(d time.Duration) *Rate {
	return &Rate{
		time: time.Now().UnixNano(),
		unit: d.Seconds(),
	}
}
func NewRateScale ( d time . Duration ) * Rate { return & Rate { time : time . Now ( ) . UnixNano ( ) , unit : d . Seconds ( ) , } }
// NewRateScale creates a new rate instruments with the given unit.
NewRateScale creates a new rate instruments with the given unit .