protected function _startBufferToMessages()
    {
        if (!Mage::getStoreConfigFlag('system/cron/enableJobOutputBuffer')) {
            return $this;
        }

        if ($this->_redirect) {
            return $this;
        }

        $this->addMessages('---START---' . PHP_EOL);

        ob_start(
            array($this, '_addBufferToMessages'),
            $this->_redirectOutputHandlerChunkSize
        );

        $this->_redirect = true;

        return $this;
    }