@Test public void toBuilder() {

  MessagingTracing messagingTracing = MessagingTracing.newBuilder(tracing).build();
  assertThat(messagingTracing.toBuilder().build())
    .usingRecursiveComparison()
    .isEqualTo(messagingTracing);
  assertThat(messagingTracing.toBuilder().producerSampler(neverSample()).build())
    .usingRecursiveComparison()
    .isEqualTo(MessagingTracing.newBuilder(tracing).producerSampler(neverSample()).build());
}