proper clean up of tracks when disconnecting

this was causing some crashes when disconnecting

@@ -353,10 +353,10 @@ constructor(
             // do nothing, may happen on older versions if attempting to unregister twice.
         }
 
+        state = State.DISCONNECTED
+        engine.close()
         cleanupRoom()
 
-        engine.close()
-        state = State.DISCONNECTED
         listener?.onDisconnect(this, null)
         listener = null
         _localParticipant?.dispose()

@@ -159,6 +159,8 @@ class RemoteParticipant(
             listener?.onTrackUnpublished(publication, this)
             eventBus.postEvent(ParticipantEvent.TrackUnpublished(this, publication), scope)
         }
+        track?.dispose()
+        publication.track = null
     }
 
     internal fun onSubscriptionPermissionUpdate(subscriptionPermissionUpdate: LivekitRtc.SubscriptionPermissionUpdate) {

@@ -6,10 +6,7 @@ import io.livekit.android.events.TrackEvent
 import io.livekit.android.room.track.video.VideoSinkVisibility
 import io.livekit.android.room.track.video.ViewVisibility
 import io.livekit.android.util.LKLog
-import kotlinx.coroutines.CoroutineDispatcher
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.SupervisorJob
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.*
 import org.webrtc.VideoSink
 import javax.inject.Named
 import kotlin.math.max
@@ -96,4 +93,9 @@ class RemoteVideoTrack(
             }
         }
     }
+
+    fun dispose() {
+        super.dispose()
+        coroutineScope.cancel()
+    }
 }
\ No newline at end of file

@@ -119,6 +119,10 @@ open class Track(
     open fun stop() {
         rtcTrack.setEnabled(false)
     }
+
+    open fun dispose() {
+        rtcTrack.dispose()
+    }
 }