title: NSData from Byte array in Swift
body: <p>I'm trying to create an <code>NSData</code> <code>var</code> from an array of bytes.</p>
  
  <p>In Obj-C I might have done this: </p>
  
  <p><code>NSData *endMarker = [[NSData alloc] initWithBytes:{ 0xFF, 0xD9 }, length: 2]</code></p>
  
  <p>I can't figure out a working equivalent in Swift.</p>