@Nullable
    public CommittableManager<CommT> getEndOfInputCommittable() {
        return checkpointCommittables.get(EOI);
    }
@Test
    void testGetEndOfInputCommittable() {
        final CommittableCollector<Integer> committableCollector =
                new CommittableCollector<>(1, 1, METRIC_GROUP);
        CommittableSummary<Integer> first = new CommittableSummary<>(1, 1, null, 1, 0, 0);
        committableCollector.addMessage(first);

        CommittableManager<Integer> endOfInputCommittable =
                committableCollector.getEndOfInputCommittable();
        assertThat(endOfInputCommittable).isNotNull();
        SinkV2Assertions.assertThat(endOfInputCommittable.getSummary())
                .hasCheckpointId(Long.MAX_VALUE);
    }