FileUpload\FileUpload::setFileSystem PHP Method

    public function setFileSystem(FileSystem $fs)
    {
        $this->filesystem = $fs;
    }

 /**
  * Create new instance of FileUpload with the preset modules
  * @param  array $upload
  * @param  array $server
  * @return FileUpload
  */
 public function create($upload, $server)
 {
     $fileupload = new FileUpload($upload, $server);
     $fileupload->setPathResolver($this->pathresolver);
     $fileupload->setFileSystem($this->filesystem);
     foreach ($this->validators as $validator) {
         $fileupload->addValidator($validator);
     }
     return $fileupload;
 }