protected function calculateCacheSlots()
    {
        $cachedScripts = $this->data['opcache_statistics']['num_cached_scripts'];
        $wasted        = $this->data['opcache_statistics']['num_cached_keys'] - $cachedScripts;
        return new ScriptSlots(
            $cachedScripts,
            $this->data['opcache_statistics']['max_cached_keys'],
            $wasted
        );
    }