@Override
    public Poller<T> refresh(List<T> items) {
        return new GenericPoller<>(items);
    }
@Test
    void testRefresh() {
        String item1 = "item1";
        String item2 = "item2";
        GenericPoller<String> poller = new GenericPoller<>(Arrays.asList(item1, item2));
        Poller<String> poller1 = poller.refresh(Arrays.asList(item2));
        assertEquals(item2, poller1.next());
    }