@Test void decoderForMessage_proto3_list() {
    assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> {
      byte[] message = SpanBytesEncoder.PROTO3.encodeList(List.of(span1, span2));
      SpanBytesDecoderDetector.decoderForMessage(message);
    });
  }
Single-element reads were for legacy non-list encoding. Don't add new code that does this
zipkin/src/test/java/zipkin2/SpanBytesDecoderDetectorTest.java