Notification system for slow processing

[weaverryan]

Having the ability to setup “alarms” of some sort, like when a queue gets beyond a certain size would be awesome. This could be executed as a custom console command possibly (so that we don’t have to hook in at runtime and start slowing things down… or maybe we hook into the worker process… again, I just don’t want to slow anything down). It would basically check the status of each queue against some configured parameters - e.g. if average waiting time in a queue exceeds 30 seconds over the last 5 minutes, we trigger a warning.