*
 * @since 26.0
 */
@ElementTypesAreNonnullByDefault
@J2ktIncompatible
public final class ExecutionSequencer {

  private ExecutionSequencer() {}

  /** Creates a new instance. */
  public static ExecutionSequencer create() {
    return new ExecutionSequencer();
  }

  /** This reference acts as a pointer tracking the head of a linked list of ListenableFutures. */

 *
 * @since 26.0
 */
@ElementTypesAreNonnullByDefault
@J2ktIncompatible
public final class ExecutionSequencer {

  private ExecutionSequencer() {}

  /** Creates a new instance. */
  public static ExecutionSequencer create() {
    return new ExecutionSequencer();
  }

  /** This reference acts as a pointer tracking the head of a linked list of ListenableFutures. */

import java.util.logging.Logger;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Tests for {@link ExecutionSequencer} */
public class ExecutionSequencerTest extends TestCase {

  ExecutorService executor;

  private ExecutionSequencer serializer;
  private SettableFuture<@Nullable Void> firstFuture;
  private TestCallable firstCallable;

  @Override

import java.util.logging.Logger;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Tests for {@link ExecutionSequencer} */
public class ExecutionSequencerTest extends TestCase {

  ExecutorService executor;

  private ExecutionSequencer serializer;
  private SettableFuture<@Nullable Void> firstFuture;
  private TestCallable firstCallable;

  @Override