public function recordUserActionOnItem(
       $event,
       $uid,
       $iid,
       array $properties=array(),
       $eventTime=null
   ) {
        $eventTime = $this->getEventTime($eventTime);
        if (empty($properties)) {
            $properties = (object)$properties;
        }
        $json = json_encode([
            'event' => $event,
            'entityType' => 'user',
            'entityId' => $uid,
            'targetEntityType' => 'item',
            'targetEntityId' => $iid,
            'properties' => $properties,
            'eventTime' => $eventTime,
        ]);

        return $this->sendRequest('POST', $this->eventUrl, $json);
    }