@Test void logsTraceId() {
    new DependencyLinker(logger).putTrace(TRACE);

    assertThat(messages)
      .contains("building trace tree: traceId=000000000000000a");
  }
In case of a late error, we should know which trace ID is being processed
zipkin/src/test/java/zipkin2/internal/DependencyLinkerTest.java