public Builder toBuilder() {
    return new Builder(this);
  }
@Test 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());
  }