gtk/print.go
func (po *PrintOperation) PrintOperationSetAllowAsync(allowSync bool) {
	C.gtk_print_operation_set_allow_async(po.native(), gbool(allowSync))
}
func (po *PrintOperation) PrintOperationSetAllowAsync(allowSync bool) {
	C.gtk_print_operation_set_allow_async(po.native(), gbool(allowSync))
}
// SetAllowAsync() is a wrapper around gtk_print_operation_set_allow_async().