@Test void errorSpan_JSON_V2() {
    assertThat(new String(SpanBytesEncoder.JSON_V2.encode(ERROR_SPAN), UTF_8))
      .isEqualTo(
        "{\"traceId\":\"dc955a1d4768875d\",\"id\":\"dc955a1d4768875d\",\"kind\":\"CLIENT\",\"localEndpoint\":{\"serviceName\":\"isao01\"},\"tags\":{\"error\":\"\"}}");
  }
the following skeletal span is used in dependency linking
zipkin/src/test/java/zipkin2/codec/SpanBytesEncoderTest.java