public async Task <bool> IsSiteAllowed(string url)
        {
            var delay = _random.Next(250, 2000);

            Debug.WriteLine($"Async task is going to take: {delay}ms");

            await Task.Delay(delay);

            return(_siteValidator.IsSiteAllowed(url));
        }
        private void OnNavigating(object sender, WebNavigatingEventArgs e)
        {
            var allowed = _siteValidator.IsSiteAllowed(e.Url);

            e.Cancel = !allowed;
        }