title: String(data: x, encoding: NSUTF8StringEncoding) equivalent in Swift 3?
body: <p>In earlier versions of Swift I could convert <code>NSData</code> to a UTF8 string thus:</p>
  
  
  
  <pre><code>let desc:String = String(data: requestData, encoding: NSUTF8StringEncoding)
  </code></pre>
  
  <p>(The documentation for <code>NSString</code>'s <code>init(data:NSData,encoding:NSStringEncoding)</code> is <a href="https://developer.apple.com/reference/foundation/nsstring/1416374-init" rel="noreferrer">here</a>.)</p>
  
  <p>In Swift 3 using <code>Data</code> I would expect something like </p>
  
  
  
  <pre><code>let desc:String = requestData.description(usedEncoding: String.Encoding.utf8)
  </code></pre>
  
  <p>But that does not exist (<code>Data</code>'s documentation is <a href="https://developer.apple.com/reference/foundation/data" rel="noreferrer">here</a>). What is the correct Swift 3 translation?</p>