In Nodejs, we have async.auto (http://caolan.github.io/async/docs.html#.auto) which automatically manages the fan out order through a topological sort.
Is there a similar library in Go that manages your order of requests
You can try this:
https://github.com/kamildrazkiewicz/go-flow
It's based on channels draining (async.auto uses topological sort) but it works in similar way.