public async Task SignOutAsync(LogoutModel logoutModel)
{
// In fact, we just add a signout date for auditing
// Because JWT is helping us to validate service-self instead of connecting back to Identity Server
// For micro-services, we need to implement distributed JWT cache for signing out all sessions
var userSession = await _userSessionRepository.GetOneAsync(logoutModel.UserSession);
userSession.SignOutDate = DateTime.UtcNow;
userSession.AlreadySignOut = true;
await _userSessionRepository.UpdateAsync(userSession.Id, userSession);
}