}

// keepAlive will continuously update lastHandout until ctx is canceled.
func (m metacache) keepAlive(ctx context.Context, rpc *peerRESTClient) {
	// we intentionally operate on a copy of m, so we can update without locks.
	t := time.NewTicker(metacacheMaxClientWait / 10)
	defer t.Stop()
	for {
		select {
		case <-ctx.Done():
			// Request is done, stop updating.
			return
		case <-t.C:
			m.lastHandout = time.Now()

   * cancelled without a call to {@code cancel}, such as by calling {@code
   * setFuture(cancelledFuture)}.
   *
   * <p>Beware of completing a future while holding a lock. Its listeners may do slow work or
   * acquire other locks, risking deadlocks.
   */
  @CanIgnoreReturnValue
  @Override
  public boolean cancel(boolean mayInterruptIfRunning) {
    @RetainedLocalRef Object localValue = value();

	// works, but only when running one binary at a time.
	// Use a file lock to make sure only one wrapper is running at a time.
	//
	// The lock file is never deleted, to avoid concurrent locks on distinct
	// files with the same path.
	lockName := filepath.Join(os.TempDir(), "go_ios_exec-"+deviceID+".lock")
	lock, err = os.OpenFile(lockName, os.O_CREATE|os.O_RDONLY, 0666)
	if err != nil {
		return 1, err
	}

    }
    ReentrantLock lock = this.lock;
    lock.lock();

    boolean satisfied = false;
    try {
      return satisfied = guard.isSatisfied();
    } finally {
      if (!satisfied) {
        lock.unlock();
      }
    }
  }

  /**
   * Enters this monitor if the guard is satisfied. Blocks at most the given time acquiring the
   * lock, but does not wait for the guard to be satisfied.

}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++
	t.requestsCount[tier] = stat
}

func (t *tierMetrics) logFailure(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.failure++
	t.requestsCount[tier] = stat
}

	// or changing an existing handler.
	apiVersion = "v1"

	// RoutePath is the remote path to connect to.
	RoutePath = "/minio/grid/" + apiVersion

	// RouteLockPath is the remote lock path to connect to.
	RouteLockPath = "/minio/grid/lock/" + apiVersion
)

// Manager will contain all the connections to the grid.
// It also handles incoming requests and routes them to the appropriate connection.
type Manager struct {

func main() {
	for _, w := range work {
		go func(w func()) {
			limit <- 1
			w()
			<-limit
		}(w)
	}
	select{}
}
</pre>

<h3 id="locks">Locks</h3>

<p>
The <code>sync</code> package implements two lock data types,
<code>sync.Mutex</code> and <code>sync.RWMutex</code>.
</p>

<p class="rule">

    checkMessage(expected, "LockC -> LockA", "LockB -> LockC", "LockA -> LockB");
  }

  public void testReentrancy_noDeadlock() {
    lockA.lock();
    lockB.lock();
    lockA.lock(); // Should not assert on lockB -> reentrant(lockA)
  }

  public void testExplicitOrdering_noViolations() {
    lock1.lock();
    lock3.lock();
    lock3.unlock();
    lock2.lock();
    lock3.lock();
  }

    checkMessage(expected, "LockC -> LockA", "LockB -> LockC", "LockA -> LockB");
  }

  public void testReentrancy_noDeadlock() {
    lockA.lock();
    lockB.lock();
    lockA.lock(); // Should not assert on lockB -> reentrant(lockA)
  }

  public void testExplicitOrdering_noViolations() {
    lock1.lock();
    lock3.lock();
    lock3.unlock();
    lock2.lock();
    lock3.lock();
  }

				Namespace: minioNamespace,
				Subsystem: "locks",
				Name:      "total",
				Help:      "Number of current locks on this peer",
				Type:      gaugeMetric,
			},
			Value: float64(st.Total),
		})
		metrics = append(metrics, MetricV2{
			Description: MetricDescription{
				Namespace: minioNamespace,
				Subsystem: "locks",
				Name:      "write_total",