title: OSX, iOS WebView: how to perform client identity authentication like safari
body: <p>How to perform authentication with a server which demands client identity certificate from OSX keychain. I see safari displaying a dialog [immage below] with a list of certificates that user can select. How can this be achieved inside an OSX app? WKNavigationDelegate does provide callback <code>- (void)webView:(WKWebView * nonnull)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *nonnull)challenge completionHandler:(void (^ nonnull)(NSURLSessionAuthChallengeDisposition disposition,NSURLCredential * nullable credential))completionHandler</code> but it doesn't get invoked.Is there any special handling required?</p>
  
  <p>Any help would be appreciable.</p>
  
  <p><img src="https://i.stack.imgur.com/QqUel.png" alt="enter image description here"></p>