void StartActivity ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & LocalUserId, const [FString](API\Runtime\Core\Containers\FString) & ActivityId, const [FOnlineEventParms](API\Plugins\OnlineSubsystem\Interfaces\FOnlineEventParms) & Parms, [FOnStartActivityComplete](API\Plugins\OnlineSubsystem\Interfaces\FOnStartActivityComplete) CompletionDelegate )