add support for ConnectTimeOutSeconds

if establishing a connection takes longer than ConnectTimeOutSeconds it will try the next address of fail the connect instead of waiting for the default timeout which is usually 20-30 seconds. Most users will want to change this to something reasonable like 6 - 10 seconds.

Author: ByronAP

src/Titanium.Web.Proxy/Network/Tcp/TcpConnectionFactory.cs

@@ -348,7 +348,38 @@ private async Task<TcpServerConnection> createServerConnection(string remoteHost
                             tcpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
                         }
 
-                        await tcpClient.ConnectAsync(ipAddress, port);
+                        var connectTask = tcpClient.ConnectAsync(ipAddress, port);
+                        await Task.WhenAny(connectTask, Task.Delay(proxyServer.ConnectTimeOutSeconds * 1000));
+                        if (!connectTask.IsCompleted || !tcpClient.Connected)
+                        {
+                            // here we can just do some cleanup and let the loop continue since
+                            // we will either get a connection or wind up with a null tcpClient
+                            // which will throw
+                            try
+                            {
+                                connectTask.Dispose();
+
+                            }
+                            catch
+                            {
+                                // ignore
+                            }
+                            try
+                            {
+#if NET45
+                                tcpClient?.Close();
+#else
+                                tcpClient?.Dispose();
+#endif
+                                tcpClient = null;
+                            }
+                            catch
+                            {
+                                // ignore
+                            }
+
+                            continue;
+                        }
                         break;
                     }
                     catch (Exception e)

src/Titanium.Web.Proxy/ProxyServer.cs

@@ -196,6 +196,12 @@ public ProxyServer(string? rootCertificateName, string? rootCertificateIssuerNam
         /// </summary>
         public int ConnectionTimeOutSeconds { get; set; } = 60;
 
+        /// <summary>
+        ///     Seconds server connection are to wait for connection to be established.
+        ///     Default value is 20 seconds.
+        /// </summary>
+        public int ConnectTimeOutSeconds { get; set; } = 20;
+
         /// <summary>
         ///     Maximum number of concurrent connections per remote host in cache.
         ///     Only valid when connection pooling is enabled.