title: Finding out what changed via postUpdate listener in Symfony 2.1
body: <p>I have a postUpdate listener and I'd like to know what the values were prior to the update and what the values for the DB entry were after the update. Is there a way to do this in Symfony 2.1? I've looked at what's stored in getUnitOfWork() but it's empty since the update has already taken place. </p>