new ClosingCallable<TestCloseable>() {
                            @Override
                            public TestCloseable call(DeferredCloser deferredCloser)
                                throws Exception {
                              deferredCloser.eventuallyClose(closeable3, closingExecutor);
                              return closeable3;
                            }
                          },

                          new ClosingCallable<TestCloseable>() {
                            @Override
                            public TestCloseable call(DeferredCloser deferredCloser)
                                throws Exception {
                              deferredCloser.eventuallyClose(closeable3, closingExecutor);
                              return closeable3;
                            }
                          },

  /**
   * An object that can capture objects to be closed later, when a {@link ClosingFuture} pipeline is
   * done.
   */
  public static final class DeferredCloser {
    @RetainedWith private final CloseableList list;

    private DeferredCloser(CloseableList list) {
      this.list = list;
    }

    /**
     * Captures an object to be closed when a {@link ClosingFuture} pipeline is done.
     *