class Expiring {

    boolean isExpired () {
        Instant now = now();
        if (expired) {
            return true;
        } else if (now.isAfter(expiryTime)) {
            expired = true;
            return true;
        }
        return false;
    }

    public  Expiring(T object, Instant expiryTime);
    public  Expiring(T object, long millis);
    public  Expiring(T object, Duration objectDuration);

}