Node.js net disconnection not detecting issue

I am new to node.js . In my program , following codes using for client close detection

 var server = net.createServer(function (stream) {
 stream.setEncoding('utf8');

 stream.on('data', function (data) { 

 if (data == '<policy-file-request/>\0') {
     var x = policy();
     stream.write(x);
     var server_date = new Date();
     var serv_sec = server_date.getSeconds();


     return;
 } 


   });


  stream.on('error', function () {


 }); 


  stream.on('close', function () 
  {

  });

when application closing , this 'close' function is working properly , whenever net disconnecting , that is not detecting by node.js