public function banClientEsiCache($eventObject) {
        $eventName = $eventObject->getEvent()->getName();
        if (Mage::helper('turpentine/esi')->getEsiEnabled() &&
                ! in_array($eventName, $this->_esiClearFlag)) {
            $sessionId = Mage::app()->getRequest()->getCookie('frontend');
            if ($sessionId) {
                $result = $this->_getVarnishAdmin()->flushExpression(
                    'obj.http.X-Varnish-Session', '==', $sessionId,
                    '&&', 'obj.http.X-Turpentine-Flush-Events', '~',
                    $eventName );
                Mage::dispatchEvent('turpentine_ban_client_esi_cache', $result);
                if ($this->_checkResult($result)) {
                    Mage::helper('turpentine/debug')
                        ->logDebug('Cleared ESI cache for client (%s) on event: %s',
                            $sessionId, $eventName);
                } else {
                    Mage::helper('turpentine/debug')
                        ->logWarn(
                            'Failed to clear Varnish ESI cache for client: %s',
                            $sessionId );
                }
            }
            $this->_esiClearFlag[] = $eventName;
        }
    }