[cairo] Not sure how to handle MIME in my go binding

[jimmy frasche]

oops, cut part of my last reply off mid-sentence and don't remember
what I was going to say there. Hope it wasn't important.

After playing with the API for a bit I settled on
https://godoc.org/github.com/jimmyfrasche/cairo/mimepattern

(code https://github.com/jimmyfrasche/cairo/tree/master/mimepattern )

The code was so much simpler with keeping the uri mimetype in that
package that I just rolled with it.

I somehow never noticed it until I went to actually implement this,
but cairo_surface_set_mime_data has a void* closure argument that's
completely undocumented. I'm just giving it 0 and hoping for the best.
What is it for?

I assumed that when setting the uri, its string representation is
what's put in data and that closure is unrelated.