@Override
 public void start() {
   collector.flushFollowModes();
   session.addActivityProducer(this);
   session.addActivityConsumer(consumer);
   session.addListener(sessionListener);
   editor.addSharedEditorListener(followModeListener);
 }
 @Override
 public void stop() {
   session.removeActivityProducer(this);
   session.removeActivityConsumer(consumer);
   session.removeListener(sessionListener);
   editor.removeSharedEditorListener(followModeListener);
   collector.flushFollowModes();
 }