ReliableFetcher#requeue_on_startup doesn't work with multiple Sidekiq processes
https://gitlab.com/gitlab-org/sidekiq-reliable-fetch/blob/83f160b37301d7dcf04129524f6cc700cc3db88e/lib/sidekiq/reliable_fetcher.rb#L80 attempts to push every job in the working queue back into the queue. However, this doesn't work if there are multiple Sidekiq processes because we could easily generate duplicates by doing:
- Run Sidekiq process A.
- Start N jobs.
- Start Sidekiq process B.
- Process B will push all unfinished jobs from the working queue back into the "regular" queue.
Edited by Stan Hu