Is that really something you want to do in-memory? Once you have to start multiple worker processes or application servers behind a load balancer, you'll have to re-implement it with some sort of shared persistant store like Redis.
Wasn't my impression (using worker processes in the same machine is common), but fair enough. On the other hand, message passing across machines is overrated. We run a SaaS service on 25 VMs with no communication between them for regular operation.
