Notify::fillReadStatuses

private function fillReadStatuses(array $notifications): array
{
	$messageIds = array_keys($notifications);

	$readStatuses = (new ReadService(BitrixImCommon::getUserId()))->getReadStatusesByMessageIds($messageIds);

	foreach ($notifications as $id => $notification)
	{
		$notifications[$id]['NOTIFY_READ'] = $readStatuses[$id] ? 'Y' : 'N';
	}

	return $notifications;
}