Sending mail with mutt+exim4 takes a long time when not connected

[Micha Feigin <michf@post.tau.ac.il>]

When my laptop isn't connected to the internet it takes about 10-15
seconds when trying to send mail with exim4 (through mutt) until the
mail gets cued.
Is it possible to do this in the background so that mutt wont hang?