internal static QiFuture SignalConnect(QiObject obj, string signature, ApiSignalCallback callback, IntPtr userdata) => new QiFuture(qi_object_signal_connect(obj.Handle, signature, callback, userdata));
private static extern IntPtr qi_object_signal_connect( IntPtr qiObj, string signature, ApiSignalCallback cb, IntPtr userdata );
internal static extern IntPtr qi_object_signal_connect( ObjectSafeHandle qiObj, string signature, ApiSignalCallback cb, IntPtr userdata );