EntityDetails::subscribeToTimelinePushEvents

private function subscribeToTimelinePushEvents(Item $entity, CurrentUser $currentUser): ?string
{
	$pushTag = null;
	if (Loader::includeModule('pull'))
	{
		$pushTag = TimelineEntry::prepareEntityPushTag($entity->getEntityTypeId(), $entity->getId());
		CPullWatch::Add($currentUser->getId(), $pushTag);
	}

	return $pushTag;
}