title: How can I add new pages to a UIPageViewController after the user has reached the last page?
body: <p>I have a <a href="http://developer.apple.com/library/ios/#documentation/uikit/reference/UIPageViewControllerClassReferenceClassRef/UIPageViewControllerClassReference.html" rel="noreferrer">UIPageViewController</a> that contains view controllers that are instantiated from data fetched over the network.  When the user is paging and gets within a few pages of the end, I kick off a new network operation and put the resulting new view controllers onto the end of my <code>UIPageViewControllerDataSource</code>'s mutable array of view controllers.  In general this all works pretty well.</p>
  
  <p>But if the network is slow (or the user is fast), it's possible to reach the final page before the network operation has completed.  Since <a href="http://developer.apple.com/library/ios/#documentation/uikit/reference/UIPageViewControllerDataSourceProtocolRef/UIPageViewControllerDataSource.html" rel="noreferrer">pageViewController:viewControllerAfterViewController:</a> gets called when the user reaches the last page, it has already returned <code>nil</code> ("to indicate that there is no next view controller").</p>
  
  <p>Is there a good way to force the UIPageViewController to call <code>pageViewController:viewControllerAfterViewController:</code> again (so that when the network operation completes and there are now new pages, I can force this call so the user can page to the new pages)?  Or is there a workaround (maybe preventing the user from paging to the last page, but still showing the bounce animation)?</p>