title: iOS: (Swift) How to show distance from current location and exist annotation on annotation subtitle
body: <p>I am currently working on map application base on iOS using Swift language. I would like an suggestion because after I plot all the pins on map view </p>
  
  <p>(which I receive data from my server using JSON frameworks call Alamofire) </p>
  
  <p>I would like the subtitle of all annotations on map to show distance from user current location.</p>
  
  <p>Now it can add annotations onto map view but can only show title and subtitle base on information receive from my server.</p>
  
  <p>Thank You.</p>