[jmileham]

Just to note that at least once delivery is the best case scenario if you configure Delayed::Job correctly, we just made it impossible to configure otherwise in our fork. The only alternative is at-most-once delivery, which puts you in Sidekiq territory with the potential for silent job loss. The semantics of exactly once delivery can only be achieved by domain-aware code, and the way to do that with any form of background job system is building jobs that are internally idempotent.