(not strictly modperl) how do I tell if ftp uploaded file is complete?

[da...@bfnet.com]

I need to create an upload progress monitor page that can discriminate
between files that are partially uploaded and those that are
completely uploaded.

My users are uploading via FTP to an anonymous upload directory.  I'm
running mod_perl on the same machine, and it has access to just about
anything on the machine that I care to give it access to.  Does anyone
have any suggestions on how I can discover from within my handler
whether an FTP file upload is complete or not?

Dave