@Override
    public V fetch(final K key, final long time) {
        Objects.requireNonNull(key, "key can't be null");
        final List<ReadOnlyWindowStore<K, V>> stores = provider.stores(storeName, windowStoreType);
        for (final ReadOnlyWindowStore<K, V> windowStore : stores) {
            try {
                final V result = windowStore.fetch(key, time);
                if (result != null) {
                    return result;
                }
            } catch (final InvalidStateStoreException e) {
                throw new InvalidStateStoreException(
                    "State store is not available anymore and may have been migrated to another instance; " +
                        "please re-discover its location from the state metadata.");
            }
        }
        return null;
    }
@Test
    public void shouldThrowInvalidStateStoreExceptionOnRebalance() {
        final StateStoreProvider storeProvider = mock(StateStoreProvider.class);
        when(storeProvider.stores(anyString(), any()))
            .thenThrow(new InvalidStateStoreException("store is unavailable"));

        final CompositeReadOnlyWindowStore<Object, Object> store = new CompositeReadOnlyWindowStore<>(
            storeProvider,
            QueryableStoreTypes.windowStore(),
            "foo"
        );

        assertThrows(InvalidStateStoreException.class, () -> store.fetch("key", ofEpochMilli(1), ofEpochMilli(10)));
    }