source.removeConsumer (this); source.addConsumer (this);
if (source != null) { source.removeConsumer (this); source.addConsumer (this); }
  flush ()  {    isLoaded = false;    isCacheable = true;    width = height = -1;    props = null;    pixelCache = null;    model = null;    source.removeConsumer (this);    source.addConsumer (this);  }