Emitting add-transceiver on webrtcbin fails

[Inrego]

Simple reproduce:

        var webrtc = ElementFactory.Make("webrtcbin", "webrtc");
        var caps = Caps.FromString("application/x-rtp,media=video,encoding-name=VP8/9000,payload=96");
        var direction = WebRTCRTPTransceiverDirection.Recvonly;
        webrtc.Emit("add-transceiver", WebRTCRTPTransceiverDirection.Recvonly, caps);

Throws the error: Invalid parameter type: expected , got Gst.WebRTC.WebRTCRTPTransceiverDirection
Link to documentation for add-transceiver: https://gstreamer.freedesktop.org/documentation/webrtc/index.html?gi-language=c#webrtcbin::add-transceiver