// Construct InstanceContext to handle messages on the callback interface. 
        // An instance of ChatApp is created and passed to the InstanceContext.
            InstanceContext site = new InstanceContext(new ChatApp());

        // Create the participant with the given endpoint configuration.
        // Each participant opens a duplex channel to the mesh.
        // Participant is an instance of the chat application that has opened a channel to the mesh.

            using (DuplexChannelFactory<IChatChannel> cf =
                new DuplexChannelFactory<IChatChannel>(site,"ChatEndpoint"))
            {
                X509Certificate2 issuer = GetCertificate(
                    StoreName.CertificateAuthority,
                    StoreLocation.CurrentUser, "CN=" + issuerName,
                    X509FindType.FindBySubjectDistinguishedName);
                cf.Credentials.Peer.Certificate =
                    GetCertificate(StoreName.My,
                    StoreLocation.CurrentUser,
                    "CN=" + member,
                    X509FindType.FindBySubjectDistinguishedName);
                cf.Credentials.Peer.PeerAuthentication.CertificateValidationMode  =
                    X509CertificateValidationMode.Custom;
                cf.Credentials.Peer.PeerAuthentication.CustomCertificateValidator =
                    new IssuerBasedValidator();

                using (IChatChannel participant = cf.CreateChannel())
                {
            // Retrieve the PeerNode associated with the participant and register for online/offline events.
            // PeerNode represents a node in the mesh. Mesh is the named collection of connected nodes.
                    IOnlineStatus ostat = participant.GetProperty<IOnlineStatus>();
                    ostat.Online += new EventHandler(OnOnline);
                    ostat.Offline += new EventHandler(OnOffline);

                    Console.WriteLine("{0} is ready", member);
                    Console.WriteLine("Press <ENTER> to send the chat message.");                   

            // Announce self to other participants.
                    participant.Join(member);
                    Console.ReadLine();
                    participant.Chat(member, "Hi there - I am chatting");

                    Console.WriteLine("Press <ENTER> to terminate this instance of chat.");
                    Console.ReadLine();
            // Leave the mesh and close the client.
                    participant.Leave(member);
                }
            }