final L listener;
    final Executor executor;

    @GuardedBy("this")
    final Queue<ListenerCallQueue.Event<L>> waitQueue = new ArrayDeque<>();

    @GuardedBy("this")
    final Queue<Object> labelQueue = new ArrayDeque<>();

    @GuardedBy("this")
    boolean isThreadScheduled;

    PerListenerQueue(L listener, Executor executor) {

  int length;

  private Segment<Object, Object> segment;
  private ReferenceEntry<Object, Object> head;
  private @Nullable ReferenceEntry<Object, Object> chain;

  @SuppressWarnings("GuardedBy")
  @BeforeExperiment
  void setUp() {
    LocalCache<Object, Object> cache =
        new LocalCache<>(CacheBuilder.newBuilder().concurrencyLevel(1), null);
    segment = cache.segments[0];
    chain = null;

  int length;

  private Segment<Object, Object> segment;
  private ReferenceEntry<Object, Object> head;
  private @Nullable ReferenceEntry<Object, Object> chain;

  @SuppressWarnings("GuardedBy")
  @BeforeExperiment
  void setUp() {
    LocalCache<Object, Object> cache =
        new LocalCache<>(CacheBuilder.newBuilder().concurrencyLevel(1), null);
    segment = cache.segments[0];
    chain = null;

   * one of three states:
   *   - Active: shutdown == false
   *   - Shutdown: runningTasks > 0 and shutdown == true
   *   - Terminated: runningTasks == 0 and shutdown == true
   */
  @GuardedBy("lock")
  private int runningTasks = 0;

  @GuardedBy("lock")
  private boolean shutdown = false;

  @Override
  public void execute(Runnable command) {
    startTask();
    try {
      command.run();
    } finally {

 * limitations under the License.
 */

package com.google.common.testing;

import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.concurrent.GuardedBy;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.logging.Handler;
import java.util.logging.LogRecord;
import org.jspecify.annotations.NullMarked;

    for (int i = 0; i < segment.threshold; i++) {
      cache.put(new Object(), new Object());
    }
    checkState(segment.table.length() == capacity);
  }

  @SuppressWarnings("GuardedBy")
  @Benchmark
  int time(int reps) {
    int dummy = 0;
    AtomicReferenceArray<ReferenceEntry<Object, Object>> oldTable = segment.table;
    for (int i = 0; i < reps; i++) {

import static com.google.common.base.Throwables.throwIfUnchecked;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.errorprone.annotations.concurrent.GuardedBy;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jspecify.annotations.NullMarked;

import static com.google.common.base.Throwables.throwIfUnchecked;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.VisibleForTesting;
import com.google.errorprone.annotations.concurrent.GuardedBy;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jspecify.annotations.NullMarked;

 * limitations under the License.
 */

package com.google.common.testing;

import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.concurrent.GuardedBy;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.logging.Handler;
import java.util.logging.LogRecord;
import org.jspecify.annotations.NullMarked;

  /**
   * The runnable, executor pairs to execute. This acts as a stack threaded through the {@link
   * RunnableExecutorPair#next} field.
   */
  @GuardedBy("lock")
  private @Nullable RunnableExecutorPair runnables;

  @GuardedBy("lock")
  private boolean executed;

  /** Creates a new, empty {@link ExecutionList}. */
  public ExecutionList() {}

  /**