private var waitingCoordinatorTask: SerialTask? = null
  private var waitingCoordinatorInterrupted = false
  private var waitingCoordinatorNotified = false

  /** How many times a new task has been started. Guarded by `this`. */
  private var contextSwitchCount = 0

  /** Guarded by `this`. */
  private var activeThreads = 0

   * escaping for code points if required.
   *
   * <p>Note that arrays returned by this method must not be modified once they have been returned.
   * However it is acceptable to return the same array multiple times (even for different input
   * characters).
   *
   * @param cp the Unicode code point to escape
   * @return the replacement characters, or {@code null} if no escaping was required
   */

   * original transformation and its inverse to a value gives you the original value give-or-take
   * numerical errors. Calling this method multiple times on the same instance will always return
   * the same instance. Calling this method on the result of calling this method on an instance will
   * always return that original instance.
   */

import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.lenient;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Nested;

In this case, it would be better to get **one extra server** and run some processes on it so that they all have **enough RAM and CPU time**.

  static void requestInterruptIn(long time, TimeUnit unit) {
    checkNotNull(unit);
    Thread interruptee = Thread.currentThread();
    new Thread(
            new Runnable() {
              @Override
              public void run() {
                try {
                  unit.sleep(time);
                } catch (InterruptedException wontHappen) {

    val elapsedUntilPong3 = System.nanoTime() - startNanos
    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedUntilPong3).toDouble())
      .isCloseTo(1500.0, 250.0)

    // The client pinged the server 3 times, and it has ponged back 3 times.
    assertThat(webSocket.sentPingCount()).isEqualTo(3)
    assertThat(server.receivedPingCount()).isEqualTo(3)
    assertThat(webSocket.receivedPongCount()).isEqualTo(3)

            assertEquals(currentTime, lastModified, "Should return correct last modified time");
            assertEquals(currentTime - 1000, lastAccess, "Should return correct last access time");
            assertEquals(currentTime - 2000, createTime, "Should return correct create time");
            assertTrue(createTime <= lastAccess, "Create time should be before or equal to last access");

import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests relating to cache expiration: make sure entries expire at the right times, make sure
 * expired entries don't show up, etc.
 *
 * @author mike nonemacher
 */
@SuppressWarnings("deprecation") // tests of deprecated method
@NullUnmarked
public class CacheExpirationTest extends TestCase {

    @RetainedLocalRef Future<?> localTimer = timer;
    // Try to cancel the timer as an optimization.
    // timer may be null if this call to run was by the timer task since there is no happens-before
    // edge between the assignment to timer and an execution of the timer task.
    if (localTimer != null) {
      localTimer.cancel(false);
    }

    delegateRef = null;
    timer = null;
  }