code: func ConnLabel(source, target enode.ID) string {
  	var first, second enode.ID
  	if bytes.Compare(source.Bytes(), target.Bytes()) > 0 {
  		first = target
  		second = source
  	} else {
  		first = source
  		second = target
  	}
  	return fmt.Sprintf("%v-%v", first, second)
  }
docs: // ConnLabel generates a deterministic string which represents a connection
  // between two nodes, used to compare if two connections are between the same
  // nodes