fix data track, use cid instead of sid

@@ -87,7 +87,8 @@ class LocalParticipant(info: LivekitModels.ParticipantInfo, private val engine:
             return
         }
 
-        val cid = track.cid
+        // data track cid isn't ready until peer connection creates it, so we'll use name
+        val cid = track.name
         val trackInfo =
             engine.addTrack(cid = cid, name = track.name, track.kind)
         val publication = TrackPublication(trackInfo, track)

@@ -7,6 +7,8 @@ import org.webrtc.MediaStreamTrack
 open class MediaTrack(name: String, kind: LivekitModels.TrackType, open val rtcTrack: MediaStreamTrack) :
     Track(name, kind) {
 
+    // TODO: how do we mute/disable a track
+
     override fun stop() {
         rtcTrack.setEnabled(false)
         rtcTrack.dispose()