/**
  * @param AdapterInterface $adapter
  * @param Config|array $config
  */
 public function __construct(AdapterInterface $adapter, $config = null)
 {
     $this->fileSystem = new FlyFileSystem($adapter, $config);
     OnSiteIndexPlugin::register($this, $this->fileSystem);
 }
 protected static function getPlugin(AdapterInterface $adapter)
 {
     $plugin = new OnSiteIndexPlugin(null, self::getInnerFileSystem($adapter));
     $plugin->setFilesystem(self::getOuterFileSystem($adapter));
     return $plugin;
 }