@Test public void send_shouldnt_tag_binary_key() {

  tracingProducer.send(new ProducerRecord<>(TEST_TOPIC, new byte[1], TEST_VALUE));
  mockProducer.completeNext();
  MutableSpan producerSpan = spans.get(0);
  assertThat(producerSpan.kind()).isEqualTo(PRODUCER);
  assertThat(producerSpan.tags())
    .containsOnly(entry("kafka.topic", TEST_TOPIC));
}