title: Manually free objects on flow scope for garbage collection
body: <p>I'm working on a WebFlow application that runs off of a single 'master' flow. This flow stores a large number of objects on the flow scope for communication between subflows. For some of these objects, I can verify that they are no longer needed and I'd like to manually free them for garbage collection rather than wait for the user to log out.</p>
  
  <p>Is there a clean way to do this, or is it a bad idea?</p>