public function currentCallback(CallbackIterator $iterator)
    {
        $clientFilename = $this->fileNames[$iterator->key()];
        $filename = $this->directory.DIRECTORY_SEPARATOR.$clientFilename;

        $fileObject = new ValueObject(file_get_contents($filename));
        $fileObject->setProperty('filename', $filename);
        $fileObject->setProperty('client_filename', $clientFilename);

        return $fileObject;
    }