return nil
	}
	totalResults := 0
	resultIndex := -1
	for _, z := range z.serverPools {
		totalResults += len(z.sets)
	}
	results = make([]dataUsageCache, totalResults)
	// Collect for each set in serverPools.
	for _, z := range z.serverPools {
		for _, erObj := range z.sets {
			resultIndex++
			wg.Add(1)
			go func(i int, erObj *erasureObjects) {