DBusProxy.addOnGSignal and Signals.connect appear to have no effect

[i-h8-github]

Hello all,

Recently, figuring out how to connect dbus signals to my code proved quite a time sink as these two methods appear to have no effect. Consider the following:

DBusProxy dBusProxy = new DBusProxy(GBusType.SESSION, GDBusProxyFlags.NONE, null, "org.freedesktop.portal.Desktop", "/org/freedesktop/portal/desktop", "org.freedesktop.portal.Settings", null);

// this delegate will never fire
dBusProxy.addOnGSignal(&onGSignal); 
// this delegate will never fire
Signals.connect(dBusProxy, "g-signal", &onGSignal);
//this callback will fire
dBusProxy.getConnection().signalSubscribe(null, null, null, null, null, DBusSignalFlags.NONE, &signalCallback, data, null);