public function load($config, array $options = array())
 {
     if (!is_string($config)) {
         $key = false;
     } else {
         $key = 'loader_' . crc32($config);
         if ($result = $this->cache->fetch($key)) {
             return $result;
         }
     }
     $result = $this->loader->load($config, $options);
     if ($key) {
         $this->cache->save($key, $result);
     }
     return $result;
 }
 private static function createFromCache(CacheAdapterInterface $cache, $cacheKey)
 {
     $cached = $cache->fetch($cacheKey);
     if ($cached instanceof CredentialsInterface && !$cached->isExpired()) {
         return new CacheableCredentials($cached, $cache, $cacheKey);
     }
     return null;
 }