code: func LoadConfig(configFile io.Reader) (string, error) {
  	var kubeconfigFile string
  	if configFile != nil {
  		// we have a config so parse it.
  		data, err := ioutil.ReadAll(configFile)
  		if err != nil {
  			return "", err
  		}
  		decoder := codecs.UniversalDecoder()
  		decodedObj, err := runtime.Decode(decoder, data)
  		if err != nil {
  			return "", err
  		}
  		config, ok := decodedObj.(*webhookadmission.WebhookAdmission)
  		if !ok {
  			return "", fmt.Errorf("unexpected type: %T", decodedObj)
  		}
  
  		if !path.IsAbs(config.KubeConfigFile) {
  			return "", field.Invalid(field.NewPath("kubeConfigFile"), config.KubeConfigFile, "must be an absolute file path")
  		}
  
  		kubeconfigFile = config.KubeConfigFile
  	}
  	return kubeconfigFile, nil
  }
docs: // LoadConfig extract the KubeConfigFile from configFile