@Test void searchDisabled_doesntAddTimestampMillis() throws Exception {
    storage.close();
    storage = ElasticsearchStorage.newBuilder(() -> WebClient.of(server.httpUri()))
      .searchEnabled(false)
      .build();
    ensureIndexTemplates(storage);
    server.enqueue(SUCCESS_RESPONSE); // for the bulk request

    Span span =
      Span.newBuilder().traceId("20").id("20").name("get").timestamp(TODAY * 1000).build();

    storage.spanConsumer().accept(List.of(span)).execute();

    assertThat(server.takeRequest().request().contentUtf8()).doesNotContain("timestamp_millis");
  }
Less overhead as a span json isn't rewritten to include a millis timestamp
zipkin-storage/elasticsearch/src/test/java/zipkin2/elasticsearch/ElasticsearchSpanConsumerTest.java