Misc small fixes: update readme about .NET 8, delete unused SocketInitiator vars, fix possible-null warning

QuickFIXn/Transport/SocketInitiator.cs

@@ -15,10 +15,6 @@ namespace QuickFix.Transport
     /// </summary>
     public class SocketInitiator : AbstractInitiator
     {
-        public const string SOCKET_CONNECT_HOST = "SocketConnectHost";
-        public const string SOCKET_CONNECT_PORT = "SocketConnectPort";
-        public const string RECONNECT_INTERVAL  = "ReconnectInterval";
-
         private volatile bool _shutdownRequested = false;
         private DateTime _lastConnectTimeDt = DateTime.MinValue;
         private int _reconnectInterval = 30;

QuickFIXn/Transport/StreamFactory.cs

@@ -72,6 +72,10 @@ internal static Stream CreateClientStream(IPEndPoint endpoint, SocketSettings se
 
             if (!settings.SocketIgnoreProxy)
             {
+                if (settings.ServerCommonName is null) {
+                    throw new ConfigError(
+                        $"{SessionSettings.SOCKET_IGNORE_PROXY}=Y needs {SessionSettings.SSL_SERVERNAME} to be set");
+                }
                 // If system has configured a proxy for this config, use it.
                 socket = CreateTunnelThruProxy(endpoint.Address.ToString(), endpoint.Port, settings.ServerCommonName);
             }

README.md

@@ -11,7 +11,7 @@ development.
 System Setup
 ------------
 
-* This project uses .NET 6.
+* This project uses .NET 8 starting with version 1.13.
 
 * All scripts are in Powershell, and should work on both Windows and Unix-based platforms.