[Dovecot] Dovecot IMAP not putting size in maildir filenames

I notice that when you move a message from one maildir folder to another, Dovecot drops the size information ("S=") from the filename. Dovecot also does not add the size info to filenames after it gets it via stat().

Shouldn't Dovecot add the size info to the filename so that "maildirsize" recalculations are fast?

Bill