// checkFailedUnlocks determines whether we have sufficiently unlocked all
// resources to ensure no deadlocks for future callers
func checkFailedUnlocks(locks []string, tolerance int) bool {
	unlocksFailed := 0
	for lockID := range locks {
		if isLocked(locks[lockID]) {
			unlocksFailed++
		}
	}

	// Unlock failures are higher than tolerance limit
	// for this instance of unlocker, we should let the

      ArrayList<LockGraphNode> acquiredLockList = requireNonNull(acquiredLocks.get());
      LockGraphNode node = lock.getLockGraphNode();
      // Iterate in reverse because locks are usually locked/unlocked in a
      // LIFO order.
      for (int i = acquiredLockList.size() - 1; i >= 0; i--) {
        if (acquiredLockList.get(i) == node) {
          acquiredLockList.remove(i);
          break;
        }
      }

An unsuccessful call has no synchronizing effect at all.
As far as the memory model is concerned,
<code>l.TryLock</code> (or <code>l.TryRLock</code>)
may be considered to be able to return false
even when the mutex <i>l</i> is unlocked.
</p>

<h3 id="once">Once</h3>

<p>
The <code>sync</code> package provides a safe mechanism for
initialization in the presence of multiple goroutines
through the use of the <code>Once</code> type.