I've submitted PR #1884 to ZF2, which provides a plugin to assist with the Post/Redirect/Get pattern (http://en.wikipedia.org/wiki/Post/Redirect/Get). TL;DR: when a user POSTs a form, they should be redirected to a GET to maintain back button support.
The plugin accepts a string as a parameter, which can be a named route or a URL (either relative or absolute, though I highly recommend absolute). Its return type falls under three basic cases:
initial GET (i.e. the user has loaded your form for the first time) - plugin will return false
POST (i.e. the user has submitted your form) - plugin will return a Zend\Http\Response object that you can, in turn, return from your controller's action
derived GET (i.e. the user has submitted your form and has been redirected) - plugin will return an array containing the POST params of the previous request