@Test protected void getTrace_deduplicates(TestInfo testInfo) throws Exception {
    String testSuffix = testSuffix(testInfo);
    Span span = spanBuilder(testSuffix).build();

    // simulate a re-processed message
    accept(span);
    accept(span);

    assertGetTraceReturns(span);
  }
Ideally, storage backends can deduplicate identical documents as this will prevent some
analysis problems such as double-counting dependency links or other statistics. While this test
exists, it is known not all backends will be able to cheaply make it pass. In other words, it
is optional.
zipkin-tests/src/main/java/zipkin2/storage/ITTraces.java