Netty 4.1: Async connect and DNS name resolving

nettyasync.scala

val boot = new Bootstrap()
  .group(new NioEventLoopGroup())
  .channel(classOf[NioSocketChannel])
  .resolver(new DnsNameResolverGroup(classOf[NioDatagramChannel], DnsServerAddresses.defaultAddresses()))
  .option(ChannelOption.TCP_NODELAY, java.lang.Boolean.TRUE)
  
val channelFuture = boot.connect(host, port)

channelFuture.addListener(new ChannelFutureListener {
  override def operationComplete(future: ChannelFuture): Unit =
  {
    if (future.isSuccess)
      // ...
    else
      future.channel().close()
  }
})