Gtk.FileFilter.prototype.add_custom

function add_custom(needed:Gtk.FileFilterFlags, func:Gtk.FileFilterFunc):void {
    // Gjs wrapper for gtk_file_filter_add_custom()
}

Adds rule to a filter that allows files based on a custom callback function. The bitfield needed which is passed in provides information about what sorts of information that the filter function needs; this allows GTK+ to avoid retrieving expensive information when it isn't needed by the filter.

Since 2.4

needed: bitfield of flags indicating the information that the custom filter function needs.
func: callback function; if the function returns true, then the file will be displayed.