code: func (t *CookieAuthTransport) RoundTrip(req *http.Request) (*http.Response, error) {
  	if t.SessionObject == nil {
  		err := t.setSessionObject()
  		if err != nil {
  			return nil, errors.Wrap(err, "cookieauth: no session object has been set")
  		}
  	}
  
  	req2 := cloneRequest(req) // per RoundTripper contract
  	for _, cookie := range t.SessionObject {
  		// Don't add an empty value cookie to the request
  		if cookie.Value != "" {
  			req2.AddCookie(cookie)
  		}
  	}
  
  	return t.transport().RoundTrip(req2)
  }
docs: // RoundTrip adds the session object to the request.