code: func Add(path string, recs []Record) error {
  	defer pathLock(path)()
  
  	if len(recs) == 0 {
  		return nil
  	}
  
  	b, err := mergeRecords(path, recs)
  	if err != nil {
  		return err
  	}
  
  	return ioutil.WriteFile(path, b, 0644)
  }
docs: // Add adds an arbitrary number of Records to an already existing /etc/hosts file