title: How can I use private APIs to block incoming calls in an iOS application?
body: <p>I would like to be able to selectively block incoming calls in an iOS application I'm writing.  This is intended for personal use, not the App Store, so I'm fine with using private APIs to accomplish this.</p>
  
  <p>I have recently come across the Core Telephony framework.  Is there a way to use this framework to block calls?  If not, what private APIs could I use to do this?</p>