--- a/net/server_event.lua	Wed Jan 04 10:53:16 2017 +0100
+++ b/net/server_event.lua	Wed Jan 04 13:18:06 2017 +0100
@@ -417,6 +417,7 @@
 	self.onreadtimeout = listener.onreadtimeout;
 	self.onstatus = listener.onstatus;
 	self.ondetach = listener.ondetach;
+	self.ondrain = listener.ondrain;
 end
 
 -- Stub handlers