Item::serializeRecursive

private function serializeRecursive($data)
{
	if ($data instanceof JsonSerializable)
	{
		$data = $data->jsonSerialize();
	}

	if (is_array($data) || $data instanceof Traversable)
	{
		foreach ($data as $key => $item)
		{
			$data[$key] = $this->serializeRecursive($item);
		}
	}

	return $data;
}