title: On Cocoa Touch/UIKit, how to detect changes to the user interface from a background thread?
body: <p>On Cocoa Touch, if we update UI elements from a background thread, bad stuff happens.</p>
  
  <p>Problem is, it doesn't happen all the time, so some mild background UI meddling might go unnoticed for a while until it kicks your right in the teeth.</p>
  
  <p>Is there a way to make UIKit run in a pedantic mode so that as soon as someone updates an element from a background thread it crashes or logs something to the console?</p>