public void LoadHtmlAsync_NSUrl()
        {
            var    completed = false;
            string d         = Path.Combine(NSBundle.MainBundle.ResourcePath, "access-denied.html");
            string g         = Path.Combine(NSBundle.MainBundle.ResourcePath, "access-granted.html");

            TestRuntime.RunAsync(DateTime.Now.AddSeconds(3000), async() => {
                using (var denied = NSUrl.FromFilename(d))
                    using (var granted = NSUrl.FromFilename(g)) {
                        var options = new NSAttributedStringDocumentAttributes {
                            ReadAccessUrl = granted
                        };
                        var r1 = await NSAttributedString.LoadFromHtmlAsync(granted, options);
                        Assert.That(r1.AttributedString.Value, Is.EqualTo("Granted"), "granted by options");
#if false
                        // this does not match my interpretation of the (headers) docs
                        var r2 = await NSAttributedString.LoadFromHtmlAsync(denied, options);
                        Assert.That(r2.AttributedString.Value, Is.Not.EqualTo("Denied"), "denied by options");
#endif
                        completed = true;
                    }
            }, () => completed);
            Assert.True(completed, "completed");
        }