decode-xml or the handlers seem not to assign record ids

[TobiasNx]

Wenn testing around Metafacture i found the following:
Internally Metafacture assinges record ids that can be seen if one encodes as formeta or triples. Usually starting by 1. Except the decoder adjust this as decode-marc21 does. I assumed that handle-marcxml would assigne the value of 001 as record id. But the record id is empty. See the example:

decode-xml with handle-marcxml:
https://metafacture.org/playground/?flux=%22https%3A//d-nb.info/1106253078/about/marcxml%22%0A%7C+open-http%28accept%3D%22application/xml%22%29%0A%7C+decode-xml%0A%7C+handle-marcxml%0A%7C+stream-to-triples%0A%7C+template%28%22%24%7Bs%7D+%7C+%24%7Bp%7D+%7C+%24%7Bo%7D%22+%29%0A%7C+print%0A%3B

But not only handle-marcxml does not assinges record ids but it seem a general isse. handle-generic-xml also assignes no id.

decode-xml with handle-generic-xml:
https://metafacture.org/playground/?flux=inputFile%0A%7C+open-file%0A%7Cdecode-xml%0A%7Chandle-generic-xml%0A%7C+stream-to-triples%0A%7C+template%28%22%24%7Bs%7D+%7C+%24%7Bp%7D+%7C+%24%7Bo%7D%22+%29%0A%7C+print%0A%3B&data=%3C%3Fxml+version%3D%221.0%22%3F%3E%0A%3Crecord%3E%0A++++%3Cfield%3Ea%3C/field%3E%0A++++%3Cfield%3Eb%3C/field%3E%0A%3C/record%3E

In contrast json start counting from 1:
https://metafacture.org/playground/?flux=inputFile%0A%7Copen-file%0A%7Cas-lines%0A%7Cdecode-json%0A%7C+stream-to-triples%0A%7C+template%28%22%24%7Bs%7D+%7C+%24%7Bp%7D+%7C+%24%7Bo%7D%22+%29%0A%7C+print%0A%3B&data=%7B%22a%22%3A+%22Faust%22%2C+%22b%22%3A+%7B%22n%22%3A+%22Goethe%22%2C+%22v%22%3A+%22JW%22%7D%2C+%22c%22%3A+%22Weimar%22%7D%0A%7B%22a%22%3A+%22R%C3%A4uber%22%2C+%22b%22%3A+%7B%22n%22%3A+%22Schiller%22%2C+%22v%22%3A+%22F%22%7D%2C+%22c%22%3A+%22Weimar%22%7D