}
    }

    // reference queues, for garbage collection cleanup

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          drainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    /**

      }
    }

    // reference queues, for garbage collection cleanup

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          drainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    /**

}

func (rt *requestTracker) trackParallelRequests() {
	if !rt.shouldTrackParallelRequests {
		// do not track parallel requests unless specifically enabled
		return
	}
	if rt.parallelLock.TryLock() {
		// lock acquired: we are the only or the first concurrent request
		// initialize the next set of parallel requests
		rt.parallelRequests = 1
	} else {
		// lock is held by other requests