Push::getRecipientByChatId

protected function getRecipientByChatId(int $chatId): array
{
	if (isset($this->recipientByChatId[$chatId]))
	{
		return $this->recipientByChatId[$chatId];
	}

	$relations = BitrixImChat::getRelation($chatId, ['SELECT' => ['ID', 'USER_ID'], 'WITHOUT_COUNTERS' => 'Y']);
	$this->recipientByChatId[$chatId] = array_keys($relations);

	return $this->recipientByChatId[$chatId];
}