Asynchronously load, render and scale an icon previously looked up from the icon theme using lookup_icon.
For more details, see load_icon which is the synchronous version of this call.
| this |
a IconInfo from lookup_icon |
| cancellable |
optional Cancellable object, null to ignore |
| callback |
a TaskReadyCallback to call when the request is satisfied |
| user_data |
the data to pass to callback function |