title: Activity indicator in SwiftUI
body: <p>Trying to add a full screen activity indicator in SwiftUI.</p>
  
  <p>I can use <code>.overlay(overlay: )</code> function in <code>View</code> Protocol. </p>
  
  <p>With this, I can make any view overlay, but I can't find the iOS default style <code>UIActivityIndicatorView</code> equivalent in <code>SwiftUI</code>.</p>
  
  <p>How can I make a default style spinner with <code>SwiftUI</code>?</p>
  
  <p><strong>NOTE:</strong> This is not about adding activity indicator in UIKit framework.</p>