private ElasticsearchBackend backend(int scrollSize) {
    ImmutableElasticsearchSetup setup = ElasticsearchSetup.builder(restClient)
            .keyExtractorFactory(KeyExtractor.noKey())
            .objectMapper(MAPPER).indexResolver(ignore -> "test").scrollSize(scrollSize).build();
    return new ElasticsearchBackend(setup);
  }
Should be greater than default elastic {@code size} which is 10.
@see <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-from-size.html">from-size</a>
criteria/elasticsearch/test/org/immutables/criteria/elasticsearch/ScrollingTest.java