Make sink private for Track

cmd/streams/producer.go

@@ -140,7 +140,7 @@ func (p *Producer) reconnect() {
 
 			// move sink from old track to new track
 			newTrack := p.element.GetTrack(media, codec)
-			newTrack.Sink = oldTrack.Sink
+			newTrack.GetSink(oldTrack)
 			p.tracks[i] = newTrack
 
 			break

cmd/streams/stream.go

@@ -129,7 +129,7 @@ func (s *Stream) RemoveConsumer(cons streamer.Consumer) {
 
 		var sink bool
 		for _, track := range producer.tracks {
-			if len(track.Sink) > 0 {
+			if track.HasSink() {
 				sink = true
 			}
 		}