Retrieves available fields for a resource.

    @type what: string
    @param what: Resource name, one of L{constants.QR_VIA_RAPI}
    @type fields: list of string
    @param fields: Requested fields

    @rtype: string
    @return: job id

def QueryFields(r, what, fields=None):
    """
    Retrieves available fields for a resource.

    @type what: string
    @param what: Resource name, one of L{constants.QR_VIA_RAPI}
    @type fields: list of string
    @param fields: Requested fields

    @rtype: string
    @return: job id
    """

    query = {}

    if fields is not None:
        query["fields"] = ",".join(fields)

    return r.request("get", "/2/query/%s/fields" % what, query=query)