In Mono/Gnome, how can I look up the icon for a mime type?

Gnome.Icon and Gnome.ThumbnailFactory both want me to pass in a URI of a file whose icon I want -- I only have a MIME type, which I want to lo开发者_Python百科ok up an icon for. Is there a GNOME C# API function which will give me what I want? Ideally the prototype would just be:

Gdk.Pixbuf LookupIcon (string mime_type);

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Here's MonoDevelop's code to do this:

MonoDevelop SVN