[Vala] using IOChannel.add_watch in a class

["Sudharshan S" <sudharsh gmail com>]

Hi everyone,
I am having a peculiar problem. In python, we add a watch using gobject.io_add_watch (..., ..., self.callbackFunc)
and the callback would be defined as follows
def callbackFunc (*self*, ..., ....):

The IOFunc? callback takes a reference to the current object as part of its arguments. But its not the same with the IOFunc definition in vala

From glib-2.0.vapi,
public delegate bool IOFunc (IOChannel source, IOCondition condition);
public uint add_watch (IOCondition condition, IOFunc func);

This definition is preventing me from passing some data to my IOFunc from add_watch. Is there a way to do this?
Shouldn't add_watch and IOFunc have an additional "..." parameter?

Regards
Sudharshan S