[go-nuts] groupcache/singleflight variation (singletrain?)

Background: I'm a golang novice and I'm writing a graph-search algorithm (it's basically "ambiguous dependency resolution" similar to what apt-get does). I want to make it concurrent, partly for fun, and partly to leverage multiple cpu cores (and, perhaps one day, multiple machines). I have a plan that involves many goroutines scurrying around the graph, and I want them to avoid duplicating each others' work.

Observation: I think I want a "duplicate function call suppression mechanism" very similar to groupcache/singleflight, but with one change. My "Getter" is not an expensive operation to deliver a valuable/reusable payload, like a flight. Rather it is like a train: an expensive operation to deliver a list of results, which may trickle in one at a time. When callers are blocked on the computation, I want them to receive the results ("traincars") as they come in, rather than waiting for the end of the computation. I think I see how to write this, but first...

Questions:
1. Am I dumb for thinking I want this?
2. If not, does something like this exist already?
3. If not, and I write it, would someone be willing to review it?
4. If I do write it, would it be so generally-useful that I should use interface{} and casting, or should I just enjoy the safety of my own bespoke types?

Thanks,
--Adam Bliss