// TestPreparedStmtConcurrentClose test calling close and executing SQL concurrently
// for example: one goroutine found error and just close the database, and others are executing SQL
// this test making sure that the gorm would not get a Segmentation Fault,
// and the only error cause by this is using a closed Stmt or gorm.ErrInvalidDB
// and all of the goroutine must got gorm.ErrInvalidDB after database close
func TestPreparedStmtConcurrentClose(t *testing.T) {

}

// NewLRWMutex - initializes a new lsync RW mutex.
func NewLRWMutex() *LRWMutex {
	return &LRWMutex{}
}

// Lock holds a write lock on lm.
//
// If the lock is already in use, the calling go routine
// blocks until the mutex is available.
func (lm *LRWMutex) Lock() {
	const isWriteLock = true
	lm.lockLoop(context.Background(), lm.id, lm.source, math.MaxInt64, isWriteLock)
}

		refreshInterval:      drwMutexRefreshInterval,
		lockRetryMinInterval: lockRetryMinInterval,
	}
}

// Lock holds a write lock on dm.
//
// If the lock is already in use, the calling go routine
// blocks until the mutex is available.
func (dm *DRWMutex) Lock(id, source string) {
	isReadLock := false
	dm.lockBlocking(context.Background(), nil, id, source, isReadLock, Options{
		Timeout: drwMutexInfinite,

## Coroutine'ler

**Coroutine**, bir `async def` fonksiyonu tarafından döndürülen değer için çok süslü bir terimdir. Python bunun bir fonksiyon gibi bir noktada başlayıp biteceğini bilir, ancak içinde bir `await` olduğunda dahili olarak da duraklatılabilir ⏸.

	closedMu sync.Mutex
	closer   io.ReadCloser
	closed   bool
}

func (pr *progressReader) Read(p []byte) (n int, err error) {
	// This ensures that Close will block until Read has completed.
	// This allows another goroutine to close the reader.
	pr.closedMu.Lock()
	defer pr.closedMu.Unlock()
	if pr.closed {
		return 0, errors.New("progressReader: read after Close")
	}
	return pr.processedReader.Read(p)
}

	}

	var id string
	if id, err = pools.initRebalanceMeta(ctx, buckets); err != nil {
		writeErrorResponseJSON(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	// Rebalance routine is run on the first node of any pool participating in rebalance.
	pools.StartRebalance()

	b, err := json.Marshal(struct {
		ID string `json:"id"`
	}{ID: id})
	if err != nil {

	neededFrags = make(map[urlFrag][]string) // URL#frag -> who needs it
)

var aRx = regexp.MustCompile(`<a href=['"]?(/[^\s'">]+)`)

// Owned by crawlLoop goroutine:
var (
	linkSources = make(map[string][]string) // url no fragment -> sources
	fragExists  = make(map[urlFrag]bool)
	problems    []string
)

func localLinks(body string) (links []string) {

		// lk2
		lk2ch := make(chan struct{})
		go func() {
			defer close(lk2ch)
			nsLk.lock(ctx, "volume", "path", "source", "opsID", false, 1*time.Millisecond)
		}()
		time.Sleep(1 * time.Millisecond) // wait for goroutine to advance; ref=2

		// Unlock the 1st lock; ref=1 after this line
		nsLk.unlock("volume", "path", false)

		// Taking another lockMapMutex here allows queuing up additional lockers. This should

	if logCh != nil {
		// We are not allowed to add when logCh is nil
		h.wg.Add(1)
		defer h.wg.Done()

	}
	h.logChMu.RUnlock()

	if logCh == nil {
		return
	}

	// Create a routine which sends json logs received
	// from an internal channel.
	for entry := range logCh {
		h.logEntry(entry)
	}
}

func (h *Target) logEntry(entry interface{}) {
	atomic.AddInt64(&h.totalMessages, 1)

   * does).
   *
   * <p>Entries with keys that have been garbage collected may be counted in {@link Cache#size}, but
   * will never be visible to read or write operations; such entries are cleaned up as part of the
   * routine maintenance described in the class javadoc.
   *
   * @return this {@code CacheBuilder} instance (for chaining)
   * @throws IllegalStateException if the key strength was already set
   */