rules/manager.go
func (g *Group) evalTimestamp() time.Time {
	var (
		offset = int64(g.hash() % uint64(g.interval))
		now    = time.Now().UnixNano()
		adjNow = now - offset
		base   = adjNow - (adjNow % int64(g.interval))
	)

	return time.Unix(0, base+offset)
}
func (g *Group) evalTimestamp() time.Time {
	var (
		offset = int64(g.hash() % uint64(g.interval))
		now    = time.Now().UnixNano()
		adjNow = now - offset
		base   = adjNow - (adjNow % int64(g.interval))
	)

	return time.Unix(0, base+offset)
}
// evalTimestamp returns the immediately preceding consistently slotted evaluation time.