func randomHeight() int {
	h := 1
	for h < maxHeight && rand.Uint32() <= heightIncrease {
		h++
	}
	return h
}
func randomHeight() int {
	h := 1
	for h < maxHeight && rand.Uint32() <= heightIncrease {
		h++
	}
	return h
}
// Returns true if key is strictly > n.key.
// If n is nil, this is an "end" marker and we return false.
//func (s *Skiplist) keyIsAfterNode(key []byte, n *node) bool {
//	y.AssertTrue(n != s.head)
//	return n != nil && y.CompareKeys(key, n.key) > 0
//}