naming issue, "performGroupedBlock" actually performs no block

[lastcc]

You named it "performGroupedBlock" but it actually performs no block, only wraps it to be performed later.

So, I guess there is a more suitable name for it?

[lastcc]

func performGroupedBlock<A,B>(block: (A,B) -> ()) -> (A,B) -> () {
        precondition(didSetup, "Did not call setup()")
        return { (a: A, b: B) -> () in
            self.performGroupedBlock {
                block(a, b)
            }
        }
 }