public void updateBatchSize(int size) {
        batchSizesUpdater.accept(size);
    }
@Test
    public void testUpdateBatchSize() {
        MetricsRegistry registry = new MetricsRegistry();
        try (FakeMetadataLoaderMetrics fakeMetrics = new FakeMetadataLoaderMetrics(registry)) {
            fakeMetrics.metrics.updateBatchSize(50);
            assertEquals(50, fakeMetrics.batchSize.get());
        }
    }