PullManager::subscribeOnEvent

protected function subscribeOnEvent(string $tag, bool $immediate = true): ?string
{
	if($this->isEnabled && !empty($tag))
	{
		$addResult = CPullWatch::Add(CurrentUser::get()->getId(), $tag, $immediate);
		if($addResult)
		{
			return $tag;
		}
	}

	return null;
}