[Evolution] mbox locking scheme ?

[Antonio Bemfica <antonio axolotl ic gc ca>]

I have my mail filtered with procmail and delivered to mbox files located
at the directory $HOME/incoming-mail/ - I know I can have Evolution
pick-up mail from spool files, but am a bit concerned with how it will
interact with the procmail delivery.

How does Evolution lock the spool files? Does it use lockfiles (if so,
what is the convention?)? Does it use kernel locks (with flock and lockf
under FreeBSD, which is the OS I use)? Does camel-lock do the locking? If
so, how?

Any light you can shed on this would be helpful - thanks in advance.

A.