public async Task <IActionResult> About()
        {
            await WriteOutIdentityInformation();

            var serviceDocEndpoint = await _httpClientProvider.GetServiceDocumentEndPoint();

            var sdcontent = await serviceDocEndpoint.GetStringAsync("");

            // get the saved identity token
            ViewData["IdentityToken"] = await HttpContext.GetTokenAsync(OpenIdConnectParameterNames.IdToken);

            //get the saved access token

            ViewData["AccessToken"] = await HttpContext.GetTokenAsync(OpenIdConnectParameterNames.AccessToken);

            var RefreshToken = await HttpContext.GetTokenAsync(OpenIdConnectParameterNames.RefreshToken);

            var expires_at = await HttpContext.GetTokenAsync("expires_at");

            @ViewData["Expiration"] = DateTime.Parse(expires_at).AddSeconds(-60).ToUniversalTime();
            @ViewData["UTC"]        = DateTime.UtcNow;

            //
            var httpClient = await _httpClientProvider.GetClient(_apiClientOption.ApiClientBaseAddress);

            var content = await httpClient.GetStringAsync("values\\Welcome");

            ViewData["Content"] = content;
            return(View());
        }