Removing the overhead of creating a new list per event

shadowsocks/eventloop.py

@@ -232,6 +232,7 @@ class EventLoop(object):
                     logging.error(e)
                     import traceback
                     traceback.print_exc()
+            if self._handlers_to_remove:
                 for handler in self._handlers_to_remove:
                     self._handlers.remove(handler)
                 self._handlers_to_remove = []