raises exception if background and wait_until_complete flags are not set...

... properly
If jobs are sent as foreground, the gearmand server will not put them in
the queue (e.g. MySQL).

The server starts run these jobs after 'wait_until_jobs_accepted'.

However, because the submit_job method returns to the caller shortly after,

what will happen is that most of these foreground jobs will be dropped by
the server and not executed.


(I have an example code confirmed this.)