private async Task SignInAsync(ApplicationUser user, bool isPersistent)
        {
            var clientKey = Request.Browser.Type;
            await UserManager.SignInClientAsync(user, clientKey);
            // Zerando contador de logins errados.
            await UserManager.ResetAccessFailedCountAsync(user.Id);

            // Coletando Claims externos (se houver)
            ClaimsIdentity ext = await AuthenticationManager.GetExternalIdentityAsync(DefaultAuthenticationTypes.ExternalCookie);

            AuthenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie, DefaultAuthenticationTypes.TwoFactorCookie, DefaultAuthenticationTypes.ApplicationCookie);
            AuthenticationManager.SignIn
                (
                    new AuthenticationProperties { IsPersistent = isPersistent },
                // Criação da instancia do Identity e atribuição dos Claims
                    await user.GenerateUserIdentityAsync(UserManager, ext)
                );
        }
 private async Task SignInAsync(ApplicationUser user, bool isPersistent)
 {
     var clientKey = Request.Browser.Type;
     await UserManager.SignInClientAsync(user, clientKey);
     AuthenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie, DefaultAuthenticationTypes.TwoFactorCookie);
     AuthenticationManager.SignIn(new AuthenticationProperties { IsPersistent = isPersistent }, await user.GenerateUserIdentityAsync(UserManager));
 }