make the MEF loading earlier

Author: kerryjiang

SocketBase/AppServerBase.cs

@@ -364,23 +364,27 @@ void CommandLoaderOnError(object sender, ErrorEventArgs e)
         }
 
         /// <summary>
-        /// Setups with the specified configurations.
+        /// Gets the composition container.
         /// </summary>
-        /// <param name="rootConfig">The root configuration.</param>
-        /// <param name="config">The server configuration.</param>
+        /// <param name="config">The configuration.</param>
         /// <returns></returns>
-        protected virtual bool Setup(IRootConfig rootConfig, IServerConfig config)
+        protected virtual ExportProvider GetCompositionContainer(IServerConfig config)
         {
             var catalog = new AggregateCatalog();
             catalog.Catalogs.Add(new AssemblyCatalog(typeof(IAppServer).Assembly));
             catalog.Catalogs.Add(new DirectoryCatalog(AppDomain.CurrentDomain.BaseDirectory, "*.dll"));
-            var compositionContainer = new CompositionContainer(catalog);
-
-            if (!Setup(rootConfig, config, compositionContainer))
-                return false;
+            return new CompositionContainer(catalog);
+        }
 
-            CompositionContainer = compositionContainer;
-            return true;
+        /// <summary>
+        /// Setups with the specified configurations.
+        /// </summary>
+        /// <param name="rootConfig">The root configuration.</param>
+        /// <param name="config">The server configuration.</param>
+        /// <returns></returns>
+        protected virtual bool Setup(IRootConfig rootConfig, IServerConfig config)
+        {
+            return Setup(rootConfig, config, CompositionContainer);
         }
 
         /// <summary>
@@ -429,6 +433,8 @@ private void SetupBasic(IRootConfig rootConfig, IServerConfig config, ISocketSer
                 m_ThreadPoolConfigured = true;
             }
 
+            CompositionContainer = GetCompositionContainer(config);
+
             if (socketServerFactory == null)
             {
                 var socketServerFactoryType =