Boxes suffers annoying leakings since we turned the RunInThreadFunc delegate argument to owned in the following commit

http://git.gnome.org/browse/gnome-boxes/commit/?id=d3c7a347ff419a787fc84d2b1529d620c5f0b335

looking at simplified generated code from:

public delegate void RunInThreadFunc () throws  GLib.Error;
public async void run_in_thread (owned RunInThreadFunc func) {
    /* some code */
}

void run_in_thread (RunInThreadFunc func, void* func_target, GDestroyNotify func_target_destroy_notify, GAsyncReadyCallback _callback_, gpointer _user_data_) {
        RunInThreadData* _data_;
        RunInThreadFunc _tmp0_;
        void* _tmp0__target;
        _data_ = g_slice_new0 (RunInThreadData);
        _data_->_async_result = g_simple_async_result_new (g_object_newv (G_TYPE_OBJECT, 0, NULL), _callback_, _user_data_, run_in_thread);
        g_simple_async_result_set_op_res_gpointer (_data_->_async_result, _data_, run_in_thread_data_free);
        _tmp0_ = func;
        _tmp0__target = func_target;
        (_data_->func_target_destroy_notify == NULL) ? NULL : (_data_->func_target_destroy_notify (_data_->func_target), NULL);
        _data_->func = NULL;
        _data_->func_target = NULL;
        _data_->func_target_destroy_notify = NULL;
        _data_->func = _tmp0_;
        _data_->func_target = _tmp0__target;
        _data_->func_target_destroy_notify = NULL;
        run_in_thread_co (_data_);
}


It seems func_target_destroy_notify is never called.