How to be notified about a painting completion?

Question

Does anyone know how to get notified when

void org.eclipse.draw2d.UpdateManager.paint(GC gc) {
    performUpdate(new Rectangle(gc.getClipping()));
}

is executed? org.eclipse.draw2d.DeferredUpdateManager.performUpdate(new Rectangle(gc.getClipping()) works asynchronously.

I looked at org.eclipse.draw2d.UpdateListener but it doesn't have a method which notifies about a painting completion.