dgram: make 'close' event async

Emit the close event asynchronously, after the close, as it is with the
net/http close events.

PR-URL: https://github.com/iojs/io.js/pull/217
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

lib/dgram.js

@@ -357,7 +357,10 @@ Socket.prototype.close = function() {
   this._stopReceiving();
   this._handle.close();
   this._handle = null;
-  this.emit('close');
+  var self = this;
+  process.nextTick(function() {
+    self.emit('close');
+  });
 
   return this;
 };

test/parallel/test-dgram-close.js

@@ -31,8 +31,12 @@ buf.fill(42);
 
 var socket = dgram.createSocket('udp4');
 var handle = socket._handle;
+var closeEvents = 0;
 socket.send(buf, 0, buf.length, common.PORT, 'localhost');
 assert.strictEqual(socket.close(), socket);
+socket.on('close', function() {
+  ++closeEvents;
+});
 socket = null;
 
 // Verify that accessing handle after closure doesn't throw
@@ -41,3 +45,7 @@ setImmediate(function() {
     console.log('Handle fd is: ', handle.fd);
   });
 });
+
+process.on('exit', function() {
+  assert.equal(closeEvents, 1);
+});