Cachearium\Backend\CacheRAM::singleton PHP Method

    public static function singleton()
    {
        static $instances;
        if (!isset($instances)) {
            $instances = new CacheRAM();
        }
        return $instances;
    }

 public function teststartCallbackRAM()
 {
     $cache = CacheRAM::singleton();
     if ($cache->isEnabled()) {
         $this->_startcallback($cache);
     }
 }