Unix timestamp to NSdate

.swift

for message in result.data.messages {
      let json = JSON(message)
      var date : NSDate!
      if let messageDate  = json["timetoken"].number {
          let dateAsInt = messageDate as NSInteger!
          let unixTime = dateAsInt / 10000000
          date = NSDate(timeIntervalSince1970: NSTimeInterval(unixTime))
      }
      println("my date \(date)")
}