Example crashes CocoaAsyncSocket in rubymotion

app_delegate.rb

class AppDelegate
  def application(application, didFinishLaunchingWithOptions:launchOptions)
    @payload = "M-SEARCH * HTTP/1.1\r\nHOST: 239.255.255.250\r\nMAN: ssdp:discover\r\nST: upnp:rootdevice\r\n"

    @socket = GCDAsyncUdpSocket.alloc.initWithDelegate(self, delegateQueue:Dispatch::Queue.main)
    @socket.bindToPort(1900, error:nil)
    @socket.beginReceiving(nil)
    puts "Socket Ready"
    
    @socket.sendData(@payload.dataUsingEncoding(NSUTF8StringEncoding), 
                     toHost:"239.255.255.250", 
                     port:1900, 
                     withTimeout:-1, 
                     tag:0)
    puts "SSDP M-SEARCH Message Sent"
    true
  end
  
  def udpSocket(socket, didReceiveData:data, fromAddress:address, withFilterContext:filterContext)
    puts "Message Received: #{data}"
  end  
end