@Nonnull
    public static RestClientBuilder client() {
        return client("localhost", DEFAULT_PORT);
    }
@Test
    public void given_clientAsString_whenReadFromElasticSource_thenFinishSuccessfully() {
        ElasticsearchContainer container = ElasticSupport.elastic.get();
        String httpHostAddress = container.getHttpHostAddress();

        indexDocument("my-index", of("name", "Frantisek"));

        Pipeline p = Pipeline.create();
        p.readFrom(ElasticSources.elastic(
                () -> ElasticClients.client(httpHostAddress),
                SearchHit::getSourceAsString)
        ).writeTo(Sinks.list(results));

        submitJob(p);

        assertThat(results).hasSize(1);
    }