}

    @Override
    public int size() {
      assertTrue(Thread.holdsLock(mutex));
      return super.size();
    }

    @Override
    public boolean isEmpty() {
      assertTrue(Thread.holdsLock(mutex));
      return super.isEmpty();
    }

    @Override
    public @Nullable V remove(Object object) {
      assertTrue(Thread.holdsLock(mutex));
      return super.remove(object);
    }

    @Override

     *       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

            logger.warn("Failed to write thread dump: file={}", file, e);
        }
    }

    /**
     * Processes all thread information and sends it to the provided consumer.
     *
     * @param writer the consumer that will handle each line of thread dump output
     */
    public static void processThreadDump(final Consumer<String> writer) {

            }
        }, 1, true);

        assertNotNull(TimeoutManager.getInstance().thread);
        Thread.sleep(2000);
        assertTrue(expiredCount > 0);
        assertEquals(1, TimeoutManager.getInstance().getTimeoutTaskCount());
        TimeoutManager.getInstance().stop();
        assertNull(TimeoutManager.getInstance().thread);
        Thread.sleep(10);
        int count = expiredCount;
        task.stop();

    .done(response -> { /* handle success */ })
    .error(throwable -> { /* handle error */ });
```

---

## Important Notes

### Thread Safety
- **Suggester**: Thread-safe for queries
- **SuggestIndexer**: Thread-safe for indexing
- **SuggestSettings**: NOT thread-safe for modifications

### Performance
- Use batch operations for indexing (100-500 items)
- Don't call `refresh()` too frequently

 *
 * It is possible to cancel the finding process by canceling its call.
 *
 * Implementations of this interface are not thread-safe. Each instance is thread-confined to the
 * thread executing the call.
 */
interface RoutePlanner {
  val address: Address

  /** Follow-ups for failed plans and plans that lost a race. */
  val deferredPlans: ArrayDeque<Plan>

    void testMonotonicBehavior() throws InterruptedException {
        Instant first = MonotonicClock.now();
        Thread.sleep(10); // Small delay
        Instant second = MonotonicClock.now();
        Thread.sleep(10); // Small delay
        Instant third = MonotonicClock.now();

        assertTrue(first.isBefore(second), "Time should progress forward between measurements");

 *   <li>a {@linkplain ThreadFactoryBuilder#setNameFormat naming format}
 *   <li>a {@linkplain Thread#setPriority thread priority}
 *   <li>an {@linkplain Thread#setUncaughtExceptionHandler uncaught exception handler}
 *   <li>a {@linkplain ThreadFactory#newThread backing thread factory}
 * </ul>
 *

  Thread newStartedThread(Runnable runnable) {
    Thread t = new Thread(runnable);
    t.setDaemon(true);
    t.start();
    return t;
  }

  /**
   * Waits for the specified time (in milliseconds) for the thread to terminate (using {@link
   * Thread#join(long)}), else interrupts the thread (in the hope that it may terminate later) and
   * fails.
   */

  class Interruptenator extends Thread {
    final AtomicBoolean shutdown;

    Interruptenator(Thread interruptee) {
      this(interruptee, new AtomicBoolean(false));
    }

    @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
    Interruptenator(Thread interruptee, AtomicBoolean shutdown) {
      super(
          new Runnable() {