how much time will it take For Training Azure Face LargePersonGroup on New Person entry which already has trained person data ?

Question

If I have LargePersonGroup with 50000 Person with 4 faces each and for them Group is already trained , now if I add 5 new person with 4 faces each to this large person group. How much time will it take to train this group again ? will it be for 5 persons only (that might be few seconds) OR will it be for 50005 persons ?

Is there any flag maintained by azure that from LargePersonGroup Old/Existing Person are already train and only new entries required training ?

Also I read I concept where a buffer PersonGroup used for new person entry and training done for that buffer only and on idle time merge those data with master and train master person group.
But that required extra efforts to sync and manage this buffer data , so any inbuilt functionality by azure that handles new person entry for training ?

Answer 1

I found one solution to this is to use PersonDirectory which do not required Training but I think it is recently introduced as I find limited details for API to perform CRUD operation and also no documentation for C# SDK.