title: Clear DNS cache on iOS programmatically
body: <p>I'm using <code>NEDNSProxyProvider</code> class for redirecting DNS traffic to my DNS server. Also I implemented feature for changing DNS server manually. My problem is <code>handleNewFlow(_:)</code> will not be called again if site was visited recently. So even if DNS server changed browser will get old IP. 
  Is it possible to clear DNS cache on iOS or just some records?</p>