func (it *Iterator) Init(list *Skiplist) {
	it.list = list
	it.arena = list.arena
	it.nd = nil
	it.value = 0
}
Init associates the iterator with a skiplist and resets all state.
package arenaskl
import (
	"runtime"
	"sync/atomic"
	"unsafe"
)
type splice struct {
	prev *node
	next *node
}
func (s *splice) init(prev, next *node) {
	s.prev = prev
	s.next = next
}
type Iterator struct {
	list  *Skiplist
	arena *Arena
	nd    *node
	value uint64
}