@SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  private void appendUserObject(StringBuilder builder, @CheckForNull Object o) {
    // This is some basic recursion detection for when people create cycles via set/setFuture or
    // when deep chains of futures exist resulting in a StackOverflowException. We could detect

    try {
      closingFuture.finishToValueAndCloser(new NoOpValueAndCloserConsumer<>(), executor);
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  // Avoid infinite recursion if a closeable's close() method throws RejectedExecutionException and
  // is closed using the direct executor.
  public void testCloseThrowsRejectedExecutionException() throws Exception {

    try {
      closingFuture.finishToValueAndCloser(new NoOpValueAndCloserConsumer<>(), executor);
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  // Avoid infinite recursion if a closeable's close() method throws RejectedExecutionException and
  // is closed using the direct executor.
  public void testCloseThrowsRejectedExecutionException() throws Exception {