title: How do I convert a WKScriptMessage.body to a struct?
body: <p>I set up the <code>WKScriptMessageHandler</code> function <code>userContentController(WKUserContentController, didReceive: WKScriptMessage)</code> to handle JavaScript messages sent to the native app. I know ahead of time that the message body will always come back with the same fields. How do I convert the <code>WKScriptMessage.body</code>, which is declared as <code>Any</code> to a struct?</p>