FaceAPI GroupInfo

           faceServiceClient = new FaceServiceClient(subscriptionKey);

            //取得所有Group
            PersonGroup[] pg = await faceServiceClient.GetPersonGroupsAsync();
      
            //計算所有Group人數
            int totalCOunt = 0;
            for(int i=0;i<pg.Length;i++)
            {
                 ClientContract.Person[] p =await faceServiceClient.GetPersonsAsync(pg[i].PersonGroupId.ToString());
                 Console.WriteLine("人數="+ p.Length.ToString());
                 totalCOunt += p.Length;
            }