static void assertClosed(TestCloseable closeable1, TestCloseable... moreCloseables)
      throws IOException {
    for (TestCloseable closeable : asList(closeable1, moreCloseables)) {
      assertWithMessage("%s.isClosed()", closeable).that(closeable.awaitClosed()).isTrue();
    }
  }

  private ClosingFuture<Object> failedClosingFuture() {
    return ClosingFuture.from(immediateFailedFuture(exception));
  }

  static void assertClosed(TestCloseable closeable1, TestCloseable... moreCloseables)
      throws IOException {
    for (TestCloseable closeable : asList(closeable1, moreCloseables)) {
      assertWithMessage("%s.isClosed()", closeable).that(closeable.awaitClosed()).isTrue();
    }
  }

  private ClosingFuture<Object> failedClosingFuture() {
    return ClosingFuture.from(immediateFailedFuture(exception));
  }