func (s *Skiplist) NewIterator(cmp CompareFn,
	buf *ActionBuffer) *Iterator {

	return &Iterator{
		cmp: cmp,
		s:   s,
		buf: buf,
		bs:  s.barrier.Acquire(),
	}
}
func (s *Skiplist) NewIterator(cmp CompareFn,
	buf *ActionBuffer) *Iterator {

	return &Iterator{
		cmp: cmp,
		s:   s,
		buf: buf,
		bs:  s.barrier.Acquire(),
	}
}
// NewIterator creates an iterator for skiplist