@Test void clientDoesntLinkToConsumer_child() {
    List<Span> trace = List.of(
      span("a", null, "a", Kind.CLIENT, "client", null, false),
      span("a", "a", "b", Kind.CONSUMER, "consumer", null, false)
    );

    assertThat(new DependencyLinker().putTrace(trace).link())
      .isEmpty();
  }
Client might be used for historical reasons instead of PRODUCER. Don't link as the server-side
is authoritative.
zipkin/src/test/java/zipkin2/internal/DependencyLinkerTest.java