code: func (c *CookieOverseer) ResetExpiry(w http.ResponseWriter, r *http.Request) error {
  	if c.options.MaxAge == 0 {
  		return nil
  	}
  
  	val, err := c.options.getCookieValue(w, r)
  	if err != nil {
  		return errors.Wrap(err, "unable to get session value from cookie")
  	}
  
  	w.(cookieWriter).SetCookie(c.options.makeCookie(val))
  
  	return nil
  }
docs: // ResetExpiry resets the age of the session to time.Now(), so that
  // MaxAge calculations are renewed