}

  /**
   * Add a shutdown hook to wait for thread completion in the given {@link ExecutorService service}.
   * This is useful if the given service uses daemon threads, and we want to keep the JVM from
   * exiting immediately on shutdown, instead giving these daemon threads a chance to terminate
   * normally.
   *
   * @param service ExecutorService which uses daemon threads

   * <p>The delegate future is interrupted and cancelled if it times out.
   *
   * @param delegate The future to delegate to.
   * @param unit the time unit of the time parameter
   * @param scheduledExecutor The executor service to enforce the timeout.
   * @since 19.0
   */
  @J2ktIncompatible
  @GwtIncompatible // java.util.concurrent.ScheduledExecutorService
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration

    public static final String UNSAFE_URL = "unsafe-url";
  }

  /**
   * The HTTP <a href="https://www.w3.org/TR/service-workers/#update-algorithm">{@code
   * Service-Worker}</a> header field name.
   *
   * @since 20.0
   */
  public static final String SERVICE_WORKER = "Service-Worker";
  /** The HTTP {@code TE} header field name. */
  public static final String TE = "TE";