code: public static ApiUser getUserAgent(User sfsUser) {
          Object userAgent = sfsUser.getProperty(APIKey.USER);
          if(userAgent == null) 
              throw new RuntimeException("Can not get user agent");
          return (ApiUser)userAgent;
      }
docs: Get user agent object mapped to smartfox user object
  
  @param sfsUser smartfox user object
  @return user agent object