public FriendAdapter(Activity context, FriendsViewModel viewModel)
		{
			this.context = context;
			this.viewModel = viewModel;
			viewModel.Friends.CollectionChanged += (sender, e) => context.RunOnUiThread (NotifyDataSetChanged);

		}
 public FriendAdapter(Activity context, FriendsViewModel viewModel)
 {
     this.context   = context;
     this.viewModel = viewModel;
     viewModel.Friends.CollectionChanged += (sender, e) => context.RunOnUiThread(NotifyDataSetChanged);
 }
		public FriendsSource (FriendsViewModel viewModel)
		{
			this.viewModel = viewModel;
		}