code: private void handleCookies(Request.Builder builder) {
  		if (!cookies.isEmpty()) {
  			builder.addHeader(HttpHeaders.COOKIE, Cookies.serialize(cookies));
  		}
  	}
docs: Add all cookies to the final request (i.e add the {@code Cookie} header).
  
  @param builder The OkHttp request builder.
  @see Request.Builder#addHeader(String, String)