code: func (iter *Iterator) limitIterator() bool {
  	if iter.node == nil {
  		return false
  	}
  
  	node := iter.node
  	if iter.startKey != nil && bytes.Compare(node.key, iter.startKey) < 0 {
  		iter.node = nil
  		return false
  	}
  
  	if iter.limitKey != nil && bytes.Compare(node.key, iter.limitKey) >= 0 {
  		iter.node = nil
  		return false
  	}
  
  	return true
  }
docs: // limitIterator clears the current iterator node if it is outside of the range
  // specified when the iterator was created.  It returns whether the iterator is
  // valid.