* {@code Ordering.natural()} if the left map uses the natural ordering of its elements. This
   * difference is an immutable snapshot of the state of the maps at the time this method is called.
   * It will never change, even if the maps change at a later time.
   *
   * <p>Since this method uses {@code TreeMap} instances internally, the keys of the right map must

      this.list = list;
    }

    /**
     * Captures an object to be closed when a {@link ClosingFuture} pipeline is done.
     *
     * <p>For users of the {@code -jre} flavor of Guava, the object can be any {@code
     * AutoCloseable}. For users of the {@code -android} flavor, the object must be a {@code
     * Closeable}. (For more about the flavors, see <a