using fetchmail to scan first few lines

[Ajit Ranade <akr@xxxxxxxxxxxxxxx>]

i would like to use fetchmail to get headers of mails before downloading
them using the pop3 protocol. this way i can avoid downloading junkmails,
esp the big ones. how do i do this? i tried reading the docs, but couldn't
find any way to do this. but i refuse to believe that this can't be done
using fetchmail.

anyone know how to do this? thanks.
-akr

ps: and btw, don't suggest that i use imap instead of pop3. that's
unfortunately not an option.