Signals, Slots mit Powermail

ext_localconf.php

$methodName = 'savePowermailData';
\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\CMS\Extbase\SignalSlot\Dispatcher')->connect(
        'In2code\Powermail\Controller\FormController',
        'createActionAfterMailDbSaved',
        'Vendor\ExtensionName\Domain\Slot',
        $methodName
);

Vendor\ExtensionName\Domain\Slot.php

class Slot  
{
    public function savePowermailData(\In2code\Powermail\Domain\Model\Mail $mail)
    {
    }
}