// Custom "wait group with timeout" for waiting for fakeServer calls in a goroutine to finish
type WaitGroup struct {
	count int32
	done  chan struct{}
}

func NewWaitGroup() *WaitGroup {
	return &WaitGroup{
		done: make(chan struct{}),
	}
}

func NewWaitForNCalls(t *testing.T, n int32) (*WaitGroup, func()) {
	wg := &WaitGroup{
		done: make(chan struct{}),
	}

	wg.Add(n)
	return wg, func() {

// - Non-healing disks
// - Healing disks (if inclHealing is true)
func (er erasureObjects) getOnlineDisksWithHealingAndInfo(inclHealing bool) (newDisks []StorageAPI, newInfos []DiskInfo, healing int) {
	var wg sync.WaitGroup
	disks := er.getDisks()
	infos := make([]DiskInfo, len(disks))
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	for _, i := range r.Perm(len(disks)) {
		i := i
		wg.Add(1)
		go func() {

func (sys *NotificationSys) StorageInfo(ctx context.Context, objLayer ObjectLayer, metrics bool) StorageInfo {
	var storageInfo StorageInfo
	replies := make([]StorageInfo, len(sys.peerClients))

	var wg sync.WaitGroup
	for i, client := range sys.peerClients {
		if client == nil {
			continue
		}
		wg.Add(1)
		go func(client *peerRESTClient, idx int) {
			defer wg.Done()

func selfSpeedTest(ctx context.Context, opts speedTestOpts) (res SpeedTestResult, err error) {
	objAPI := newObjectLayerFn()
	if objAPI == nil {
		return SpeedTestResult{}, errServerNotInitialized
	}

	var wg sync.WaitGroup
	var errOnce sync.Once
	var retError string
	var totalBytesWritten uint64
	var totalBytesRead uint64

	objCountPerThread := make([]uint64, opts.concurrency)

		// TOTAL
		time.Sleep(2 * testDrwMutexAcquireTimeout)
		// fmt.Println("Unlocking dm1")

		dm1st.Unlock(context.Background())
	}()
	expect += 2 * testDrwMutexAcquireTimeout

	var wg sync.WaitGroup
	wg.Add(2)

	go func() {
		defer wg.Done()

		dm2nd.Lock(id, source)

		// Release lock after 10 seconds
		go func() {
			time.Sleep(2 * testDrwMutexAcquireTimeout)

// and re-arranges the disks in proper position.
func (s *erasureSets) connectDisks(log bool) {
	defer func() {
		s.lastConnectDisksOpTime = time.Now()
	}()

	var wg sync.WaitGroup
	diskMap := s.getDiskMap()
	for _, endpoint := range s.endpoints.Endpoints {
		cdisk := diskMap[endpoint]
		if cdisk != nil && cdisk.IsOnline() {
			if s.lastConnectDisksOpTime.IsZero() {
				continue
			}

	ctx, cancel := context.WithTimeout(ctx, ds.Timeouts.ForceUnlockCall)
	defer cancel()

	restClnts, _ := ds.GetLockers()

	args := LockArgs{
		UID: id,
	}

	var wg sync.WaitGroup
	for index, c := range restClnts {
		wg.Add(1)
		// Send refresh request to all nodes
		go func(index int, c NetLocker) {
			defer wg.Done()
			c.ForceUnlock(ctx, args)
		}(index, c)
	}
	wg.Wait()

	}
	for i := range w.buffer {
		delete(w.buffer, i)
	}
	w.wg.Wait()
	return err
}

type writerAt struct {
	w      *io.PipeWriter
	r      *io.PipeReader
	wg     *sync.WaitGroup
	buffer map[int64][]byte
	err    error

	nextOffset int64
	m          sync.Mutex
}

func (w *writerAt) WriteAt(b []byte, offset int64) (n int, err error) {
	w.m.Lock()
	defer w.m.Unlock()

type metacacheWriter struct {
	streamErr   error
	mw          *msgp.Writer
	creator     func() error
	closer      func() error
	blockSize   int
	streamWg    sync.WaitGroup
	reuseBlocks bool
}

// newMetacacheWriter will create a serializer that will write objects in given order to the output.
// Provide a block size that affects latency. If 0 a default of 128KiB will be used.

	o.debugln("Raw List", o)
	filterCh := make(chan metaCacheEntry, o.Limit)
	listCtx, cancelList := context.WithCancel(ctx)
	filteredResults := o.gatherResults(listCtx, filterCh)
	var wg sync.WaitGroup
	wg.Add(1)
	var listErr error

	go func(o listPathOptions) {
		defer wg.Done()
		o.StopDiskAtLimit = true
		listErr = z.listMerged(listCtx, o, filterCh)
		o.debugln("listMerged returned with", listErr)