}

    @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) {

            }

            // When
            for (Thread thread : threads) {
                thread.start();
            }
            for (Thread thread : threads) {
                thread.join();
            }

            // Then
            for (int i = 0; i < threadCount; i++) {
                assertTrue(success[i], "Thread " + i + " failed");
            }
        }

        @Test

            }
        }, 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();

            }
          }
        });
    awaitUninterruptibly(enteredLatch);
  }

  @CanIgnoreReturnValue
  static Thread startThread(Runnable runnable) {
    Thread thread = new Thread(runnable);
    thread.setDaemon(true);
    thread.start();
    return thread;
  }

  /**
   * Generates a test case verifying that calling any enterXxx, tryEnterXxx, or waitForXxx method

    }

    @Test
    public void testThreadSafety() throws InterruptedException {
        // Test concurrent updates from multiple threads
        Thread[] threads = new Thread[10];

        for (int i = 0; i < threads.length; i++) {
            final int index = i;
            threads[i] = new Thread(() -> {
                for (int j = 0; j < 100; j++) {
                    String name = "file" + index + "_" + j + ".txt";

    .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");