Issue #2762. Add callback to close function.

Author: mikeal

doc/api/http.markdown

@@ -137,7 +137,7 @@ a listener for the ['listening'](net.html#event_listening_) event.
 See also [net.Server.listen()](net.html#server.listen).
 
 
-### server.close()
+### server.close([cb])
 
 Stops the server from accepting new connections.
 See [net.Server.close()](net.html#server.close).

doc/api/net.markdown

@@ -162,11 +162,11 @@ Stop accepting connections for the given number of milliseconds (default is
 one second).  This could be useful for throttling new connections against
 DoS attacks or other oversubscription.
 
-#### server.close()
+#### server.close([cb])
 
 Stops the server from accepting new connections. This function is
 asynchronous, the server is finally closed when the server emits a `'close'`
-event.
+event. Optionally, you can pass a callback to listen for the `'close'` event.
 
 
 #### server.address()

lib/net.js

@@ -885,12 +885,15 @@ function onconnection(clientHandle) {
 }
 
 
-Server.prototype.close = function() {
+Server.prototype.close = function(cb) {
   if (!this._handle) {
     // Throw error. Follows net_legacy behaviour.
     throw new Error('Not running');
   }
 
+  if (cb) {
+    this.once('close', cb);
+  }
   this._handle.close();
   this._handle = null;
   this._emitCloseIfDrained();

test/simple/test-net-server-close.js

@@ -27,16 +27,14 @@ var assert = require('assert');
 var net = require('net');
 
 var server = net.createServer(function(socket) {
-  server.close();
+  server.close(function() {
+    assert.equal(server.connections, 0);
+  });
   process.nextTick(function() {
     socket.destroy();
   });
 });
 
 server.listen(common.PORT, function() {
   net.createConnection(common.PORT);
-});
-
-server.on('close', function() {
-  assert.equal(server.connections, 0);
-});
+});