}

  /**
   * Marks this step as the last step in the {@code ClosingFuture} pipeline. When this step is done,
   * {@code receiver} will be called with an object that contains the result of the operation. The
   * receiver can store the {@link ValueAndCloser} outside the receiver for later synchronous use.
   *
   * <p>After calling this method, you may not call {@link #finishToFuture()}, this method again, or

    7+. These platforms lack support for TLS 1.2 and should not be used. But because upgrading is
    difficult we will backport critical fixes to the 3.12.x branch through December 31, 2021. (This
    commitment was originally through December 31, 2020; we have since extended it.)

 *  **TLSv1 and TLSv1.1 are no longer enabled by default.** Major web browsers are working towards