[Gtk-sharp-list] Setting data on widget

[Ivan Radovanovic]

After few hours of googling I couldn't find what is recommended way to 
connect data to any widget, so I am curious if anyone can point me in 
the right direction.
What I am trying to achieve is to simply associate some piece of data 
with button so I can determine what button is clicked in event handler 
(I am looking for something equivalent to "Tag" property on 
System.Windows.Forms.Control class). I found mentioning of UserData 
property, SetData method & friends in gtk#, but all these are deprecated 
without further pointer in favor of what method/property they have been 
deprecated.
I am 100% aware that this can be solved by using some hashtable in class 
that contains all widgets, but I wouldn't like to reinvent the wheel 
unless I need to :-)

Best regards,
Ivan