I would like to send notifications to players when, for example, someone adds them to their friend list so they can see a message like "X has added you as a friend." Unlike standard push notifications, I'm talking about informing them of events that happen when they are online.
Does PlayFab support server-to-client messages, maybe through something like SignalR? If not, should I use push notifications for this purpose?
Otherwise, how viable is using PlayerData (or TitleData for non player specific messages) to save such events and have the clients poll them every X seconds, performance-wise?