*
     * @return the {@link CrawlerContext} for the current thread, or {@code null} if no context is set.
     */
    public static CrawlerContext getCrawlerContext() {
        return ROBOT_CONTEXT_THREAD_LOCAL.get();
    }

    /**
     * Sets the current {@link CrawlerContext} for the current thread.
     * If the provided {@code crawlerContext} is {@code null}, the context is removed from the thread-local storage.

  @GuardedBy("queue")
  private WorkerRunningState workerRunningState = IDLE;

  /**
   * This counter prevents an ABA issue where a thread may successfully schedule the worker, the
   * worker runs and exhausts the queue, another thread enqueues a task and fails to schedule the
   * worker, and then the first thread's call to delegate.execute() returns. Without this counter,

        // Trip circuit
        circuitBreaker.trip();
        Thread.sleep(100);

        long afterTripTime = circuitBreaker.getTimeSinceLastStateChange();
        assertTrue(afterTripTime >= 100, "Time should have advanced");
        assertTrue(afterTripTime < 200, "Time should be reasonable");

        // Reset circuit
        circuitBreaker.reset();
        Thread.sleep(50);

        for (int i = 0; i < threadCount; i++) {
            final int threadId = i;
            new Thread(() -> {
                try {
                    WebApiUtil.setObject("key" + threadId, "value" + threadId);
                    WebApiUtil.getObject("key" + threadId);
                    WebApiUtil.setError(400 + threadId, "Error " + threadId);
                    WebApiUtil.validate();
                } catch (Exception e) {

- "unfinished_work_microseconds" is added to the workqueue metrics; it can be used to detect stuck worker threads. (kube-controller-manager runs many workqueues.) ([#70884](https://github.com/kubernetes/kubernetes/pull/70884), [@lavalamp](https://github.com/lavalamp))

            final int threadId = i;
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        startLatch.await();
                        for (int j = 0; j < rulesPerThread; j++) {
                            TestRule rule = new TestRule("rule_" + threadId + "_" + j, true);

 *
 *  * For asynchronous calls made with [Call.enqueue], an [IOException] is propagated to the caller
 *    indicating that the call was canceled. The interceptor's exception is delivered to the current
 *    thread's [uncaught exception handler][Thread.UncaughtExceptionHandler]. By default this
 *    crashes the application on Android and prints a stacktrace on the JVM. (Crash reporting
 *    libraries may customize this behavior.)
 *

     *       observing a null thread does not mean the object is safe to reuse.
     *   <li>If this field's value is some other thread object, we know that it's not our thread.
     *   <li>If this field's value == null because it originally belonged to another thread and that
     *       thread cleared it, we still know that it's not associated with our thread

          }
          buffer.add(e);
          added++;
        }
      }
    } finally {
      if (interrupted) {
        Thread.currentThread().interrupt();
      }
    }
    return added;
  }

  /**
   * Returns a synchronized (thread-safe) queue backed by the specified queue. In order to guarantee
   * serial access, it is critical that <b>all</b> access to the backing queue is accomplished

        for (int t = 0; t < threadCount; t++) {
            final int threadId = t;
            executor.submit(() -> {
                try {
                    for (int i = 0; i < operationsPerThread; i++) {
                        String sid = "thread-" + threadId + "-key-" + i;
                        byte[] key = keyManager.generateRandomKey(16);

                        // Store key