dotnet add package Microsoft.AspNetCore.SignalR.Client

public class ChatService
{
    HubConnection? _hub;

    public async Task ConnectAsync(string token)
    {
        _hub = new HubConnectionBuilder()
            .WithUrl("https://api.example.com/chathub", opts =>
                opts.AccessTokenProvider = () => Task.FromResult(token)!)
            .WithAutomaticReconnect()
            .Build();

        // Subscribe to server-pushed messages
        _hub.On<string, string>("ReceiveMessage", (user, msg) =>
            MainThread.BeginInvokeOnMainThread(() =>
                Messages.Add(new ChatMessage(user, msg))));

        await _hub.StartAsync();
    }

    public async Task SendAsync(string msg) =>
        await _hub!.SendAsync("SendMessage", msg);

    public async Task DisconnectAsync() =>
        await _hub!.StopAsync();
}