interface vcd_mgr {
    void set_foreground(in int pid, in int value) async;
    int get_private_data(in int pid, in string key, out string data);
    int auth_enable(in int pid);
    int auth_disable(in int pid);
    int auth_start(in int pid);
    int auth_stop(in int pid);
    int auth_cancel(in int pid);
}