if !s.checkID(params.DiskID) {
		return grid.NewRemoteErr(errDiskNotFound)
	}
	if params.Cache == nil {
		return grid.NewRemoteErrString("NSScannerHandler: provided cache is nil")
	}

	// Collect updates, stream them before the full cache is sent.
	updates := make(chan dataUsageEntry, 1)
	var wg sync.WaitGroup
	wg.Add(1)
	go func() {