title: What could be causing the  following error regarding MKTileCache?
body: <p>In the console, I'm seeing the following error when my application runs:</p>
  
  <blockquote>
    <p>void -[MKTileCache
    synchronize](MKTileCache*,
    objc_selector*) called while in
    background</p>
  </blockquote>
  
  <p>What could this error mean, and how can I prevent it?</p>