gstreamer/gstreamer-sharp/Message.custom

    [DllImport("gstreamersharpglue-0.10")]
    private extern static IntPtr gstsharp_message_parse_error(IntPtr raw);

    public void ParseError(out string error)
    {
        IntPtr err = gstsharp_message_parse_error(Handle);
        error = GLib.Marshaller.PtrToStringGFree(err);
    }