Some XKMS comments: Pending results; <Respond>

I thought I'd get the ball rolling by providing some general comments (i.e.
not specific to X-KRSS or X-KISS) that I have on the XKMS draft.

i) The "pending" result code will be troublesome unless there is an
indication for how the client should react to such a result code, e.g. Do
they wait 5 mins, 10 mins, 24 hours, before sending in a new request? It
seems likely that any follow-up request should refer to the original request
as well.  I believe that similar issues came up with a similar result code
in CMP.  I suppose that there are a few options
- remove this result code
- add a new request message the allows the user to "ping" the status of an
expected response (similar to what is done for the proposed bulk operations)
- rely on the underlying transport protocol (I'm least familiar with how
this option would work but it is a workaround that is proposed for CMP)

ii) There is no clear guidance as to which <Respond> elements (given in
Section 3.1.5) are applicable to which operations. For example, "Multiple"
doesn't seem to make sense for an X-KRSS request so that there should be
some general guidance indicating that an X-KRSS server would ignore
"Multiple" if included in the <Respond> element of an X-KRSS request. (If
people agree this is important, I can write some text related to this.) In
addition, there's no schema for the list of choices for <Respond>. Would it
not make sense to define as a Choice element as opposed to just listing the
possible values within the document itself?

Cheers,
Mike