Comment 52 for bug 1690980

Re inhibitor: One can run u-u --download-only from cron first without the inhibitor then the full u-u with the inhibitor. While this method does not allow per-transaction granularity, it is a fairly good solution without added complexity.
I someone comes up with a proper patch it may be integrated but I think this is out of the scope of this bug. The committed solution already provides the per-transaction stopping granularity when u-u is started by apt's service.