* to be closed asynchronously <b>after</b> the returned {@code Future} is done: the future
 * completes before closing starts, rather than once it has finished.
 *
 * <pre>{@code
 * FluentFuture<UserName> userName =
 *     ClosingFuture.submit(
 *             closer -> closer.eventuallyClose(database.newTransaction(), closingExecutor),
 *             executor)

    final ListenableFuture<String> future;
    final String name;
    final Runnable finisher;

    TestFuture(ListenableFuture<String> future, String name, Runnable finisher) {
      this.future = future;
      this.name = name;
      this.finisher = finisher;
    }
  }

  /**
   * A collection of several futures, covering cancellation, success, and failure (both {@link

    final ListenableFuture<String> future;
    final String name;
    final Runnable finisher;

    TestFuture(ListenableFuture<String> future, String name, Runnable finisher) {
      this.future = future;
      this.name = name;
      this.finisher = finisher;
    }
  }

  /**
   * A collection of several futures, covering cancellation, success, and failure (both {@link