}

  /**
   * Signals some other thread waiting on a satisfied guard, if one exists.
   *
   * <p>We manage calls to this method carefully, to signal only when necessary, but never losing a
   * signal, which is the classic problem of this kind of concurrency construct. We must signal if

        pendingDescription = "Exception thrown from implementation: " + e.getClass();
      }
      // The future may complete during or before the call to getPendingToString, so we use null
      // as a signal that we should try checking if the future is done again.
      if (!isNullOrEmpty(pendingDescription)) {
        builder.append("PENDING, info=[").append(pendingDescription).append("]");
      } else if (isDone()) {

   * Error}, or else as a last resort, wraps it in a {@code RuntimeException} and then propagates.
   *
   * <p>This method always throws an exception. The {@code RuntimeException} return type allows
   * client code to signal to the compiler that statements after the call are unreachable. Example
   * usage:
   *
   * <pre>
   * T doSomething() {
   *   try {
   *     return someMethodThatCouldThrowAnything();

   * Error}, or else as a last resort, wraps it in a {@code RuntimeException} and then propagates.
   *
   * <p>This method always throws an exception. The {@code RuntimeException} return type allows
   * client code to signal to the compiler that statements after the call are unreachable. Example
   * usage:
   *
   * <pre>
   * T doSomething() {
   *   try {
   *     return someMethodThatCouldThrowAnything();

   */
  public static final byte NAK = 21;

  /**
   * Synchronous Idle: A communication control character used by a synchronous transmission system
   * in the absence of any other character to provide a signal from which synchronism may be
   * achieved or retained.
   *
   * @since 8.0
   */
  public static final byte SYN = 22;

  /**

  /**
   * The HTTP <a
   * href="https://wicg.github.io/turtledove/#handling-direct-from-seller-signals">{@code
   * Ad-Auction-Signals}</a> header field name.
   *
   * @since 33.0.0
   */
  public static final String AD_AUCTION_SIGNALS = "Ad-Auction-Signals";

  /**
   * The HTTP <a href="https://wicg.github.io/turtledove/#http-headerdef-ad-auction-allowed">{@code

      // If signal() fails somehow, we should see a failed test, even without looking at the Future.
      Future<?> unused =
          scheduledPool.schedule(
              new Runnable() {
                @Override
                public void run() {
                  testCondition.signal();
                }
              },
              delay,

  }

  /**
   * Inserts element at current put position, advances, and signals. Call only when occupying
   * monitor.
   */
  private void insert(E x) {
    items[putIndex] = x;
    putIndex = inc(putIndex);
    ++count;
  }

  /**
   * Extracts element at current take position, advances, and signals. Call only when occupying
   * monitor.
   */
  private E extract() {

      // If signal() fails somehow, we should see a failed test, even without looking at the Future.
      Future<?> unused =
          scheduledPool.schedule(
              new Runnable() {
                @Override
                public void run() {
                  testCondition.signal();
                }
              },
              delay,

  }

  /**
   * Inserts element at current put position, advances, and signals. Call only when occupying
   * monitor.
   */
  private void insert(E x) {
    items[putIndex] = x;
    putIndex = inc(putIndex);
    ++count;
  }

  /**
   * Extracts element at current take position, advances, and signals. Call only when occupying
   * monitor.
   */
  private E extract() {