Question about add node to Variable

[woodliu]

Before add a node to Variable, it needs to call findBucket to find a location for the node.

func (v *Variable[K, V]) findBucket(expiration uint32) node.Node[K, V] {
	duration := expiration - v.time
	length := len(v.wheel) - 1
	for i := 0; i < length; i++ {
		if duration < spans[i+1] {
			ticks := expiration >> shift[i]
			index := ticks & (buckets[i] - 1)
			return v.wheel[i][index]
		}
	}
	return v.wheel[length][0]
}

My question is why use ticks := expiration >> shift[i] (not ticks := duration >> shift[i]) to calculate the location in v.wheel[i] ?
I think use ticks := duration >> shift[i] is more reasonable, because it represent the distance(Or time difference) from the avaliable data location(v.time>> shift[i]). expiration is a random value(unixtime.Now()+ttl), it can be anywhere in v.wheel[i], conflict with the RemoveExpired.

[woodliu]

Sorry, if use ticks := duration >> shift[i], it needs to add the v.time too...