[9fans] synthetic filesystems and changing data

[John Marshall <John.Marshall@ec.gc.ca>]

Hi,

I am trying to understand the general practice, under
Plan 9, for synthetic filesystems for serving up a "file"
which:
1) returns data that changes (quickly), and
2) returns data whose size is larger than the message
    size agreed upon at *version interchange.

Practically, what I am wondering is:
1) what to do when the "file" content changes between
    multiple *read operations (assuming that the reads
    are done quickly)? Is it just tough luck for the client?
2) whether or not synthetic filesystems generally handle
    (or not) the offset parameter? I imagine to do this
    requires relatively static content, is difficult, or
    there is an assumption that the size of the content
    _must_ fit in the message.

Thanks,
John