@Override public void commandSucceeded(CommandSucceededEvent event) {
    Span span = threadLocalSpan.remove();
    if (span == null) return;
    span.finish();
  }
@Test void commandSucceeded_withoutCommandStarted() {
    listener.commandSucceeded(createCommandSucceededEvent());

    verify(threadLocalSpan).remove();
    verifyNoMoreInteractions(threadLocalSpan);
  }