Read/Write multiple returners
Clean out the old jobs from all returners (if you have it)
Merge the return data from all returners
Return all job data from all returners
Merge the load data from all returners
Call both with prep_jid on all returners in multi_returner
TODO: finish this, what do do when you get different jids from 2 returners... since our jids are time based, this make this problem hard, because they aren't unique, meaning that we have to make sure that no one else got the jid and if they did we spin to get a new one, which means "locking" the jid in 2 returners is non-trivial
Write return to all returners in multi_returner
Write load to all returners in multi_returner
Included for API consistency