public function setRegenerateCycles($cycles = self::DEFAULT_REGENERATE_CYCLES)
    {
        // do we need to do anything? cause a "0" means deactivated!
        $this->regenerateCycles = $cycles;

        // set only if cycle count is given
        if ($cycles > 0) {
            // execute right after session start
            $this->callStack['start']['regenerate'] = [
                $this,
                'handleRegenerate',
            ];
        } else {
            // remove from callstack if exists
            if (isset($this->callStack['start']['regenerate'])) {
                unset($this->callStack['start']['regenerate']);
            }
        }
    }