@Override
  public final Throwable failureCause() {
    return delegate.failureCause();
  }

  /** @since 15.0 */
  @CanIgnoreReturnValue
  @Override
  public final Service startAsync() {
    delegate.startAsync();
    return this;
  }

  /** @since 15.0 */
  @CanIgnoreReturnValue
  @Override
  public final Service stopAsync() {
    delegate.stopAsync();
    return this;
  }