title: At the current storyboard, how do I find which view controller segued the view there?
body: <p>Say I'm at a specific view controller that one of several view controllers could have brought the user to. How do I find which one it is? Because I need to add a specific button in the toolbar for if it segued from a specific view controller.</p>
  
  <p>(In <code>prepareForSegue:</code> you can find the destination view controller, I'm wondering if there's a way to find the opposite, the source view controller, so to speak.)</p>
  
  <p>Is the only way to store it as a property of the class?</p>