/// <summary>
        /// Login in Twitter (LoginViaTwitterCommand handler)
        /// </summary>
        private async void LoginViaTwitter()
        {
            Analytics.TrackEvent("Twitter login button clicked",
                                 new Dictionary <string, string>
            {
                { "Page", "Login" },
                { "Category", "Clicks" }
            });

            ITwitter twitterService = DependencyService.Get <ITwitter>(DependencyFetchTarget.GlobalInstance);

            twitterService.OnError += error => AuthError("Twitter", error);

            SocialAccount account = await twitterService.Login();

            await Login(account, "Twitter");
        }