XMLParser.parse() stops execution

I'm exhausted, have no idea what's going on.

private var _parser: XMLParser = XMLParser();
public var delegate: ModelFactoryDelegate?;

override internal func response() -> Bool
{
    print("SessionFactory::response(1)");
    self._parser = XMLParser(data: self._content.content);
    print("SessionFactory::response(2)");
    self._parser.delegate = self;
    print("SessionFactory::response(3)");
    self._parser.parse();
    print("SessionFactory::response(4)");
    self.close(nil);
    print("SessionFactory::response(5)");

    return true;
}

func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String])
{
    print("ModelFactory::parser(1)");
    if (elementName == "id") {
        self._mark = true;
        print("ModelFactory::parser(2)");
    }
    print("ModelFactory::parser(3)");
}

func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?)
{

}

func parser(_ parser: XMLParser, foundCharacters string: String)
{
    if (self._mark) {
        if (self.delegate != nil) {
            print("ModelFactory::parser(4)");
            self.delegate!.onInit(id: AIndex(string.trimmingCharacters(in: .newlines))!);
            print("ModelFactory::parser(5)");
        }
        self._mark = false;
    }
}

Output

AceController::onNextButtonTouchUpInside(1)
HTTPSocket::receive(1)
HTTPSocket::receive(2)
SessionFactory::response(1)
SessionFactory::response(2)
SessionFactory::response(3)
AceController::onInit(1)
Session::open(1)

Why .parse() can stop execution?

Any ideas would be appreciated.