Used at the end of a POST request to determine which view will be
redirected to. As well as the String result returned from the action method,
this may also use information stored in the ThreadErrorState to make its
decision for the final view.
author: Antranig Basman (antranig@caret.cam.ac.uk)
An ARIResult representing the desired view and flow state for thejust completed action. This may be null if the ARI determinesthat it is not appropriate for this action cycle and wishes to delegateto another.