public class RoomsAuthProvider : CredentialsAuthProvider
{
    private int userId = 0;

    public RoomsAuthProvider(AppSettings appSettings) : base(appSettings)
    {
    }

    public RoomsAuthProvider()
    {
    }

    public override bool TryAuthenticate(IServiceBase authService,
        string userName, string password)
    {
        if (password == "ValidPassword")
        {
            return true;
        }

        else
        {
            return false;
        }
    }

    public override IHttpResult OnAuthenticated(IServiceBase authService,
        IAuthSession session, IAuthTokens tokens,
        Dictionary<string, string> authInfo)
    {
        //Fill IAuthSession with data you want to retrieve in the app eg:
        session.FirstName = "some_firstname_from_db";
        //...

        //Call base method to Save Session and fire Auth/Session callbacks:
        return base.OnAuthenticated(authService, session, tokens, authInfo);

        //session.CreatedAt = DateTime.Now;
        //session.DisplayName = "CustomDisplayName" + userId;
        //session.IsAuthenticated = true;
        //session.UserAuthName = session.UserName;
        //session.UserAuthId = userId.ToString();

        //Interlocked.Increment(ref userId);

        //authService.SaveSession(session, SessionExpiry);
        //return null;
    }
}

[Authenticate]
public class ServerEventsService : Service
{
...
}

var client = new ServerEventsClient("http://localhost:1337/", "home")
{
    OnConnect = OnConnect,
    OnCommand = HandleIncomingCommand,
    OnMessage = HandleIncomingMessage,
    OnException = OnException,
    OnHeartbeat = OnHeartbeat
}.Start();

client.Connect().Wait();

var authResponse = client.Authenticate(new Authenticate
{
    provider = "credentials",
    UserName = "test@gmail.com",
    Password = "p@55w0rd",
    RememberMe = true,
});

client.ServiceClient.Post(new PostChatToChannel
{
    Channel = "home",     // The channel we're listening on
    From = client.SubscriptionId, // Populated after Connect()
    Message = "Hello, World!",
});