code: func NewClient(services *disco.Disco, client *http.Client) *Client {
  	if services == nil {
  		services = disco.New()
  	}
  
  	if client == nil {
  		client = httpclient.New()
  		client.Timeout = requestTimeout
  	}
  
  	services.Transport = client.Transport
  
  	return &Client{
  		client:   client,
  		services: services,
  	}
  }
docs: // NewClient returns a new initialized registry client.