title: How to add circular region onto MKMapView
body: <p>I am trying to add a circular region on my MKMapView like the picture below for my current location. I can pin the map with annotations but don't know how to get it to show a circular region like this with a radius and have it shaded.</p>
  
  <p><img src="https://i.stack.imgur.com/RxvvW.png" alt="enter image description here"></p>