private async void SignInBtn_Click(object sender, RoutedEventArgs e)
        {
            MessageTB.Text    = "";
            Loader.Visibility = Visibility.Visible;
            var user     = UserNameTB.Text;
            var password = PasswordTB.Password;

            try
            {
                User signedInUser = await UserConnection.AuthenticateUser(new User()
                {
                    Username = user, Password = password
                });

                SignedIn?.Invoke(this, new SignedInEventArgs()
                {
                    User = signedInUser
                });
                ApplicationRuntimeData.AuthUser = new WebApi.Models.AuthUser()
                {
                    Username = user, Password = password
                };
                ApplicationRuntimeData.CurrentUser = signedInUser;
            }
            catch (Exception ex)
            {
                MessageTB.Text = ex.Message;
            }
            Loader.Visibility = Visibility.Hidden;
        }