Get a site's Favicon uri

Using HtmlAgilityPack NuGet package (Ms-Pl license):

    public async static Task<Uri> GetFaviconUri(Uri page)
    {
        var doc = await new HtmlAgilityPack.HtmlWeb().LoadFromWebAsync(page.AbsoluteUri);
        var href = doc.DocumentNode.Descendants("link")
            .Where(n => n.Attributes.Any(a => a.Name == "rel" &&
                a.Value == "icon" || a.Value == "shortcut icon"))
            .FirstOrDefault()?.GetAttributeValue("href", null);
        return href == null ? null : new Uri(page, href);
    }