code: func (t *Iterator) PeekWalk(walkFn func(item Item) bool) {
  	for i := t.lastPos + 1; i < len(t.l.items); i++ {
  		item := t.l.items[i]
  		if !walkFn(item) {
  			break
  		}
  	}
  }
docs: // PeekWalk will feed the next items in the iterator to walkFn
  // until it returns false.