code: func (c *Client) Result(req *Request, resp interface{}) error {
  	result, err := c.Do(req)
  	if err != nil {
  		return err
  	}
  	return unmarshal(result, resp)
  }
docs: // Result performs the request described by req and unmarshals a successful
  // HTTP response into resp. If resp is nil, the response is discarded.