[Modify] Polish it

Author: sta

websocket-sharp/Net/HttpListener.cs

@@ -472,18 +472,17 @@ private void cleanupWaitQueue (Exception exception)
     private void close (bool force)
     {
       if (_listening) {
-        _listening = false;
-
-        EndPointManager.RemoveListener (this);
-      }
-
-      lock (_contextRegistrySync)
         cleanupContextQueue (!force);
+        cleanupContextRegistry ();
+
+        var name = GetType ().ToString ();
+        var ex = new ObjectDisposedException (name);
+        cleanupWaitQueue (ex);
 
-      cleanupContextRegistry ();
+        EndPointManager.RemoveListener (this);
 
-      var ex = new ObjectDisposedException (GetType ().ToString ());
-      cleanupWaitQueue (ex);
+        _listening = false;
+      }
 
       _disposed = true;
     }