is_expired example

public function before_request($url, &$headers, &$data, &$type, &$options) {
        if (!$url instanceof Iri) {
            $url = new Iri($url);
        }

        if (!empty($this->cookies)) {
            $cookies = [];
            foreach ($this->cookies as $key => $cookie) {
                $cookie = $this->normalize_cookie($cookie, $key);

                // Skip expired cookies                 if ($cookie->is_expired()) {
                    continue;
                }

                if ($cookie->domain_matches($url->host)) {
                    $cookies[] = $cookie->format_for_header();
                }
            }

            $headers['Cookie'] = implode('; ', $cookies);
        }
    }