bind_matrix_setting
Description:
Binds the [property@SpaceDrawer:matrix] property to a [class@Gio.
Settings] key.
The [class@Gio.Settings] key must be of the same type as the [property@SpaceDrawer:matrix] property, that is, `"au"`.
The [method@Gio.Settings.bind] function cannot be used, because the default GIO mapping functions don't support [struct@GLib.Variant] properties (maybe it will be supported by a future GIO version, in which case this function can be deprecated).
Parameters:
| this | a SpaceDrawer object. | 
| settings | a Settings object. | 
| key | the  | 
| flags | flags for the binding. |