set_absolute_size
Description:
Sets the size field of a font description, in device units.
This is mutually exclusive with [method@Pango.FontDescription.set_size] which sets the font size in points.
Parameters:
| this | a `PangoFontDescription` | 
| size | the new size, in Pango units. There are pango_scale Pango units  in one device unit. For an output 
            backend where a device unit is a pixel,  a  |