private function getTransport()
    {
        if ($this->transport) {
            return $this->transport;
        }

        $transportClassName = '\\Sokil\\Upload\\Transport\\' . $this->options['transport'] . 'Transport';

        $this->transport = new $transportClassName(
            $this->options['fieldName'],
            $this->options['supportedFormats'],
            $this->options['validateChecksum']
        );
        
        return $this->transport;
    }