@Test void decoderForListMessage_unknown() {
    assertThatExceptionOfType(IllegalArgumentException.class).isThrownBy(() -> {
      SpanBytesDecoderDetector.decoderForListMessage(new byte[]{'h'});
    });
  }
There is no difference between a list of size one and a single element in proto3
zipkin/src/test/java/zipkin2/SpanBytesDecoderDetectorTest.java