@Override void writeValue(WriteBuffer b, Endpoint value) {
      SERVICE_NAME.write(b, value.serviceName());
      IPV4.write(b, value.ipv4Bytes());
      IPV6.write(b, value.ipv6Bytes());
      PORT.write(b, value.portAsInt());
    }
This is the only field in the ListOfSpans type
zipkin/src/main/java/zipkin2/internal/Proto3ZipkinFields.java