allow_async

Determines whether the print operation may run asynchronously or not.

Some systems don't support asynchronous printing, but those that do will return gtk_print_operation_result_in_progress as the status, and emit the [signal@Gtk.PrintOperation:GtkPrintOperation:done] signal when the operation is actually done.

The Windows port does not support asynchronous operation at all (this is unlikely to change). On other platforms, all actions except for gtk_print_operation_action_export support asynchronous operation.