Input::parseCommandFromCallback

private function parseCommandFromCallback(array $data): ?string
{
	if (isset($data['BX_COMMAND']))
	{
		return $data['BX_COMMAND'];
	}

	if (isset($data['dlvStatus']))
	{
		return 'receivingStatusDelivery';
	}

	if (isset($data['imSubject']))
	{
		return 'receivingMessage';
	}

	return null;
}