pub trait RTSPMediaFactoryExtManual {
    fn add_role(&self, roles: &[(&str, &ToSendValue)]);
}

impl<O: IsA<RTSPMediaFactory>> RTSPMediaFactoryExtManual for O {
    fn add_role(&self, roles: &[(&str, &ToSendValue)]) {
        for &(f, v) in roles {
            let sv = v.to_send_value();
            ffi::gst_rtsp_media_factory_add_role(self.to_glib_none().0, "plop".to_glib_none().0, v.type_(), v.get(), None);
        }
    }
}