code: func (hst HTTPProxyCheck) Check() (warnings, errorList []error) {
  	klog.V(1).Infoln("validating if the connectivity type is via proxy or direct")
  	u := (&url.URL{Scheme: hst.Proto, Host: hst.Host}).String()
  
  	req, err := http.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, []error{err}
  	}
  
  	proxy, err := netutil.SetOldTransportDefaults(&http.Transport{}).Proxy(req)
  	if err != nil {
  		return nil, []error{err}
  	}
  	if proxy != nil {
  		return []error{errors.Errorf("Connection to %q uses proxy %q. If that is not intended, adjust your proxy settings", u, proxy)}, nil
  	}
  	return nil, nil
  }
docs: // Check validates http connectivity type, direct or via proxy.