counter.Add(1) // account for the following goroutine
	go func() {
		defer counter.Add(-1) // account completion of this goroutine
		idle1 = req1.Finish(func() {
			executed1 = true
			ctx2, cancel2 := context.WithCancel(context.Background())
			tBefore := clk.Now()
			counter.Add(1) // account for the following goroutine
			go func() {
				defer counter.Add(-1) // account completion of this goroutine