[Modify] Polish it

websocket-sharp/Net/HttpListenerResponse.cs

@@ -1071,8 +1071,10 @@ namespace WebSocketSharp.Net
     /// </exception>
     public void Redirect (string url)
     {
-      if (_disposed)
+      if (_disposed) {
-        throw new ObjectDisposedException (GetType ().ToString ());
+        var name = GetType ().ToString ();
+        throw new ObjectDisposedException (name);
+      }
 
       if (_headersSent) {
         var msg = "The response is already being sent.";