// Simple Helpers
public static List <UserId> UserIdsInPrivateRoom(RoomId roomId) => roomId.ToString().Split('-').Select(id => (UserId)int.Parse(id)).ToList();
public static UserId PartnerIdFrom(RoomId roomId, UserId userId)
{
var userIds = roomId.ToString().Split('-').Select(int.Parse).ToArray();
return(userId == userIds[0] ? userIds[1] : userIds[0]);
}
