private void HandleAcceptedClient(SecureSocket incomingClient, ALPNExtensionMonitor monitor)
        {
            bool backToHttp11 = false;
            string selectedProtocol = Protocols.Http1;
            
            if (_useHandshake)
            {
                try
                {
                    if (_options.Protocol != SecureProtocol.None)
                    {
                        incomingClient.MakeSecureHandshake(_options);
                        selectedProtocol = incomingClient.SelectedProtocol;
                    }
                }
                catch (SecureHandshakeException ex)
                {
                    switch (ex.Reason)
                    {
                        case SecureHandshakeFailureReason.HandshakeInternalError:
                            backToHttp11 = true;
                            break;
                        case SecureHandshakeFailureReason.HandshakeTimeout:
                            incomingClient.Close();
                            Http2Logger.LogError("Handshake timeout. Client was disconnected.");
                            return;
                        default:
                            incomingClient.Close();
                            Http2Logger.LogError("Unknown error occurred during secure handshake");
                            return;
                    }
                }
                catch (Exception e)
                {
                    Http2Logger.LogError("Exception occurred. Closing client's socket. " + e.Message);
                    incomingClient.Close();
                    return;
                }
            }

            var clientStream = new DuplexStream(incomingClient, true);
            var transportInfo = GetTransportInfo(incomingClient);

            monitor.Dispose();

            try
            {
                HandleRequest(clientStream, selectedProtocol, transportInfo, backToHttp11);
            }
            catch (Exception e)
            {
                Http2Logger.LogError("Exception occurred. Closing client's socket. " + e.Message);
                incomingClient.Close();
            }
        }
        public bool Connect(Uri connectUri)
        {
            _path = connectUri.PathAndQuery;
            _version = Protocols.Http2;
            _scheme = connectUri.Scheme;
            _host = connectUri.Host;
            _port = connectUri.Port;
            ServerUri = connectUri.Authority;

            if (_sessionAdapter != null)
            {
                return false;
            }

            try
            {
                int port = connectUri.Port;

                int securePort;

                if (!int.TryParse(ConfigurationManager.AppSettings["securePort"], out securePort))
                {
                    Http2Logger.LogError("Incorrect port in the config file!");
                    return false;
                }


                //Connect alpn extension, set known protocols
                var extensions = new[] {ExtensionType.Renegotiation, ExtensionType.ALPN};

                Options = port == securePort
                               ? new SecurityOptions(SecureProtocol.Tls1, extensions, new[] { Protocols.Http1, Protocols.Http2 },
                                                     ConnectionEnd.Client)
                               : new SecurityOptions(SecureProtocol.None, extensions, new[] { Protocols.Http1, Protocols.Http2 },
                                                     ConnectionEnd.Client);

                Options.VerificationType = CredentialVerification.None;
                Options.Certificate = Org.Mentalis.Security.Certificates.Certificate.CreateFromCerFile(CertificatePath);
                Options.Flags = SecurityFlags.Default;
                Options.AllowedAlgorithms = SslAlgorithms.RSA_AES_256_SHA | SslAlgorithms.NULL_COMPRESSION;

                var socket = new SecureSocket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp, Options);
                using (var monitor = new ALPNExtensionMonitor())
                {
                    monitor.OnProtocolSelected += (o, args) => { _selectedProtocol = args.SelectedProtocol; };
                    socket.Connect(new DnsEndPoint(connectUri.Host, connectUri.Port), monitor);

                    _clientStream = new DuplexStream(socket, true);

                    if (_useHandshake)
                    {
                        MakeHandshakeEnvironment();
                        //Handshake manager determines what handshake must be used: upgrade or secure

                        if (socket.SecureProtocol != SecureProtocol.None)
                        {
                            socket.MakeSecureHandshake(Options);
                            _selectedProtocol = socket.SelectedProtocol;
                        }

                        if (socket.SecureProtocol == SecureProtocol.None || _selectedProtocol == Protocols.Http1)
                        {
                            try
                            {
                                var handshakeResult = new UpgradeHandshaker(_environment).Handshake();
                                _environment.Add(HandshakeKeys.Result, handshakeResult);
                                _useHttp20 = handshakeResult[HandshakeKeys.Successful] as string == HandshakeKeys.True;

                                if (!_useHttp20)
                                {
                                    Dispose(false);
                                    return true;
                                }
                            }
                            catch (Http2HandshakeFailed ex)
                            {
                                if (ex.Reason == HandshakeFailureReason.InternalError)
                                {
                                    _useHttp20 = false;
                                }
                                else
                                {
                                    Http2Logger.LogError("Specified server did not respond");
                                    Dispose(true);
                                    return false;
                                }
                            }
                        }
                    }
                }

                Http2Logger.LogDebug("Handshake finished");

                if (_useHttp20)
                {
                    //TODO provide transport info
                    _sessionAdapter = new Http2ClientMessageHandler(_clientStream, ConnectionEnd.Client, default(TransportInformation),
                                                                     CancellationToken.None);
                }
            }
            catch (SocketException)
            {
                Http2Logger.LogError("Check if any server listens port " + connectUri.Port);
                Dispose(true);
                return false;
            }
            catch (Exception ex)
            {
                Http2Logger.LogError("Unknown connection exception was caught: " + ex.Message);
                Dispose(true);
                return false;
            }

            return true;
        }
        public static DuplexStream GetHandshakedDuplexStream(string address, bool allowHttp2Communication = true, bool useMock = false)
        {
            string selectedProtocol = null;

            var extensions = new[] { ExtensionType.Renegotiation, ExtensionType.ALPN };
            var useHandshake = ConfigurationManager.AppSettings["handshakeOptions"] != "no-handshake";

            var protocols = new List<string> { Protocols.Http1 };
            if (allowHttp2Communication)
            {
                protocols.Add(Protocols.Http2);
            }

            var options = UseSecurePort
                              ? new SecurityOptions(SecureProtocol.Tls1, extensions, protocols,
                                                    ConnectionEnd.Client)
                              : new SecurityOptions(SecureProtocol.None, extensions, protocols,
                                                    ConnectionEnd.Client);

            options.VerificationType = CredentialVerification.None;
            options.Certificate = Org.Mentalis.Security.Certificates.Certificate.CreateFromCerFile(@"certificate.pfx");
            options.Flags = SecurityFlags.Default;
            options.AllowedAlgorithms = SslAlgorithms.RSA_AES_256_SHA | SslAlgorithms.NULL_COMPRESSION;

            var sessionSocket = new SecureSocket(AddressFamily.InterNetwork, SocketType.Stream,
                                                ProtocolType.Tcp, options);

            using (var monitor = new ALPNExtensionMonitor())
            {
                monitor.OnProtocolSelected += (sender, args) => { selectedProtocol = args.SelectedProtocol; };

                var uri = new Uri(GetAddress() + address);

                sessionSocket.Connect(new DnsEndPoint(uri.Host, uri.Port), monitor);

                if (useHandshake)
                {
                    sessionSocket.MakeSecureHandshake(options);
                }
            }

            //SendSessionHeader(sessionSocket);

            return useMock ? new Mock<DuplexStream>(sessionSocket, true).Object : new DuplexStream(sessionSocket, true);
        }