code: func (c *Client) Discover(host svchost.Hostname, serviceID string) (*url.URL, error) {
  	service, err := c.services.DiscoverServiceURL(host, serviceID)
  	if err != nil {
  		return nil, &ServiceUnreachableError{err}
  	}
  	if !strings.HasSuffix(service.Path, "/") {
  		service.Path += "/"
  	}
  	return service, nil
  }
docs: // Discover queries the host, and returns the url for the registry.