/// <summary>
 /// Displays authentication UI to the user for the specified request URI, returning
 /// the key value pairs from the query string upon reaching the callback URL.
 /// </summary>
 /// <param name="requestUri">The request URI.</param>
 /// <param name="callbackUri">The callback URI.</param>
 /// <returns>The <see cref="IDictionary{string, string}"/> of key value pairs from the callback URI query string.</returns>
 public async Task<IDictionary<string, string>> AuthenticateAsync(Uri requestUri, Uri callbackUri)
 {
     using (var formsDialog = new FormsWebDialog())
     {
         var responseValues = await formsDialog.GetAuthenticationResponseValues(requestUri, callbackUri);
         return responseValues;
     }
 }
        /// <summary>
        /// Displays authentication UI to the user for the specified request URI, returning
        /// the key value pairs from the query string upon reaching the callback URL.
        /// </summary>
        /// <param name="requestUri">The request URI.</param>
        /// <param name="callbackUri">The callback URI.</param>
        /// <returns>The <see cref="IDictionary{string, string}"/> of key value pairs from the callback URI query string.</returns>
        public async Task <IDictionary <string, string> > AuthenticateAsync(Uri requestUri, Uri callbackUri)
        {
            using (var formsDialog = new FormsWebDialog())
            {
                var responseValues = await formsDialog.GetAuthenticationResponseValues(requestUri, callbackUri);

                return(responseValues);
            }
        }