debug: check for fn._name as well

lib/application.js

@@ -80,7 +80,7 @@ app.listen = function(){
 
 app.use = function(fn){
   assert('GeneratorFunction' == fn.constructor.name, 'app.use() requires a generator function');
-  debug('use %s', fn.name || '-');
+  debug('use %s', fn._name || fn.name || '-');
   this.middleware.push(fn);
   return this;
 };