Sets the `GtkCellLayout`DataFunc to use for this.
This function is used instead of the standard attributes mapping for setting the column value, and should set the value of this’s cell renderer(s) as appropriate.
func may be null to remove a previously set function.
| this |
a `GtkCellLayout` |
| cell |
a `GtkCellRenderer` |
| func |
the `GtkCellLayout`DataFunc to use |
| destroy |
destroy notify for |
| func_data |
user data for |