Problem with Offlineimap hanging

[John Wiegley]

Sometimes I see this in my *offlineimap* log:

--8<---------------cut here---------------start------------->8---
Hook stdout: 
Hook stderr:

Hook return code: 0
Sleeping for 15:00
Establishing connection to tunnel:/opt/local/libexec/dovecot/imap.
Syncing INBOX: IMAP -> MappedIMAP
***** Finished processing account Gmail
Copying folder structure from IMAP to MappedIMAP
imap(johnw): Info: Disconnected for inactivity bytes=126/11145
--8<---------------cut here---------------end--------------->8---

At this point, Offlineimap hangs forever, and only a 'kill' at the
command-line will cure it.  This, even though I have 'keepalive = 30' set.

Is there a way that Offlineimap could simply restart if it detects that it's
been disconnected?  I would have thought SIGUSR2 would prompt it to resume in
this condition, but it does not.

Thanks,
  John