public override async Task OnConnectedAsync()
{
var userName = Context.User.GetUserName();
var isOnline = await _tracker.UserConnected(userName, Context.ConnectionId);
if (isOnline)
{
await Clients.Others.SendAsync("UserIsOnline", userName);
}
var connectedUsers = await _tracker.GetUsersOnline();
await Clients.Caller.SendAsync("GetUsersOnline", connectedUsers);
}