public function addKey(PreFileDownloadEvent $event)
    {
        $processedUrl = $event->getProcessedUrl();

        if ($this->isAcfProPackageUrl($processedUrl)) {
            $rfs = $event->getRemoteFilesystem();
            $acfRfs = new RemoteFilesystem(
                $this->addParameterToUrl(
                    $processedUrl,
                    'k',
                    $this->getKeyFromEnv()
                ),
                $this->io,
                $this->composer->getConfig(),
                $rfs->getOptions(),
                $rfs->isTlsDisabled()
            );
            $event->setRemoteFilesystem($acfRfs);
        }
    }