unsafe extern "C" fn trampoline_link_function<T, F: Fn(&T, Option<&Object>, &Pad) -> Result<PadLinkSuccess, PadLinkError> + Send + Sync + 'static>( pad: *mut GstPad, parent: *mut GstObject, peer: *mut GstPad, ) -> GstPadLinkReturnwhere T: IsA<Pad>,