webrtcsink: panics on create_from_uri(RTP_TWCC_URI).unwrap()

When doing:

GST_DEBUG=3 gst-launch-1.0 videotestsrc ! agingtv ! webrtcsink enable-data-channel-navigation=true meta="meta,name=native-stream"

webrtcsink panics at:

let twcc_extension = gst_rtp::RTPHeaderExtension::create_from_uri(RTP_TWCC_URI).unwrap();

with:

thread 'tokio-runtime-worker' panicked at 'called `Option::unwrap()` on a `None` value', net/webrtc/src/webrtcsink/imp.rs:681:76

That's expected as "create_from_uri" is not guaranteed to return non-null values.

I see create_from_uri is trying to get something from gst_registry, but this "URL" is not there in my registry... Any advice of how to check/add this URI? Thanks.