I've dug around and found a few comments and even some examples of how to use these functions. However, it begs the question - why do these functions need callback drivers? Why cant they return the data in a string like the mail_fetch... functions?
The original intent of partial fetching was to permit resource-limited clients to do so without requiring a potentially huge memory buffer. You don't generally want to do a fetch-as-string for a 600MB video file.
I don't think that a callback function is all that hard to write.
-- Mark --
http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.
