Backbone Collection Fetch Scheduler

It's tricky to properly manage the the fetching of several Backbone collections in a given application. There are factors at play that require close attention. We don't want to put too much load on the server. We don't want to put too much load on the client. We need to consider things such as concurrency, and the ability to prioritize based on collection freshness. This seems like a lot to take on, and it maybe overkill to worry about such matters in smaller applications. But as the sheer volume of collections grows, as the complexity between the collection relationships increases, you're going to need some sort of fetch scheduling strategy.