protected function extractNextDataString($data, $lastPosition) {
        $substring = substr($data, $lastPosition);
        $reader = new BinnReader();
        $container = $reader->readNext($substring);
        $substring = $container->getByteString();
        $substringLength = strlen($substring);
        $nextIndex = $lastPosition + $substringLength;
        unset($reader);
        unset($container);
        unset($substringLength);
        return [$substring, $nextIndex];
    }