public Timer add(long interval, TimerHandler handler, Object... args)
    {
        if (handler == null) {
            return null;
        }
        return new Timer(timer.add(interval, handler, args));
    }
@Test
    public void testCancelTwice()
    {
        Timer timer = timers.add(10, handler);
        assertThat(timer, notNullValue());

        boolean rc = timer.cancel();
        assertThat(rc, is(true));

        rc = timer.cancel();
        assertThat(rc, is(false));
    }