this.data.subscriptionChanged(); if (out != null) { sendUpdate(out); endMessage(out);
synchronized (lock) { data.subscriptionChanged(); if (out != null) { sendUpdate(out); endMessage(out); }
    public void subscriptionChanged (Subscription sub) {      this.data.subscriptionChanged();      if (out != null) {        sendUpdate(out);        endMessage(out);      }    }