BaseMessage::generateSubject

static function generateSubject(
	$providerTypeId = null,
	$direction = \CCrmActivityDirection::Undefined,
	array $replace = null
)
{
	if ($direction === \CCrmActivityDirection::Incoming)
	{
		return Loc::getMessage(
			sprintf(
				'CRM_ACTIVITY_PROVIDER_%s_INCOMING',
				static::getLangProviderId()
			),
			$replace
		);
	}
	elseif ($direction === \CCrmActivityDirection::Outgoing)
	{
		return Loc::getMessage(
			sprintf(
				'CRM_ACTIVITY_PROVIDER_%s_OUTGOING',
				static::getLangProviderId()
			),
			$replace
		);
	}

	return parent::generateSubject($providerTypeId, $direction, $replace);
}