/**
  * @param $username
  * @return User|null
  */
 public function getUserByUsername($username)
 {
     $cached = $this->getCachedUserByUsername($username);
     if ($cached) {
         return $cached;
     }
     $user = $this->userService->getUserByUsername($username);
     if ($user) {
         $this->cacheUser($user);
     }
     return $user;
 }