diff --git a/History.md b/History.md
new file mode 100644
index 0000000..643d557
--- /dev/null
+++ b/History.md
@@ -0,0 +1,16 @@
+
+0.2.0 / 2013-11-06 
+==================
+
+  * use keepalive agent on node 0.11+ impl
+
+0.1.5 / 2013-06-24 
+==================
+
+  * support coveralls
+  * add node 0.10 test
+  * add 0.8.22 original https.js
+  * add original http.js module to diff
+  * update jscover
+  * mv pem to fixtures
+  * add https agent usage
diff --git a/example/agent.js b/example/agent.js
new file mode 100644
index 0000000..8cfacf2
--- /dev/null
+++ b/example/agent.js
@@ -0,0 +1,44 @@
+var http = require('http');
+var Agent = require('../');
+
+var keepaliveAgent = new Agent({
+  keepAlive: true
+});
+// https://www.google.com/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8
+var options = {
+  host: 'gitcafe.com',
+  path: '/',
+  method: 'GET',
+  agent: keepaliveAgent
+};
+
+var start = Date.now();
+var req = http.get(options, function (res) {
+  console.log('STATUS1: %d, %d ms', res.statusCode, Date.now() - start);
+  console.log('HEADERS1: %j', res.headers);
+  res.setEncoding('utf8');
+  res.on('data', function (chunk) {
+    console.log('BODY1: %d', chunk.length);
+  });
+  res.on('end', function () {
+    process.nextTick(function () {
+      start = Date.now();
+      http.get(options, function (res) {
+        console.log('STATUS2: %d, %d ms', res.statusCode, Date.now() - start);
+        console.log('HEADERS2: %j', res.headers);
+        res.setEncoding('utf8');
+        res.on('data', function (chunk) {
+          console.log('BODY2: %d', chunk.length);
+        });
+      });
+    });
+  });
+});
+req.on('error', function (e) {
+  console.log('problem with request: ' + e.message);
+});
+
+setTimeout(function () {
+  console.log('keep alive sockets:', keepaliveAgent);
+  process.exit();
+}, 3000);
diff --git a/example/https_agent.js b/example/https_agent.js
index 034023b..272620a 100644
--- a/example/https_agent.js
+++ b/example/https_agent.js
@@ -1,22 +1,38 @@
 var https = require('https');
 var HttpsAgent = require('../').HttpsAgent;
 
-var keepaliveAgent = new HttpsAgent();
+var keepaliveAgent = new HttpsAgent({
+  keepAlive: true
+});
 // https://www.google.com/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8
 var options = {
-  host: 'www.google.com',
+  host: 'github.com',
   port: 443,
-  path: '/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8',
+  path: '/',
   method: 'GET',
   agent: keepaliveAgent
 };
 
+var start = Date.now();
 var req = https.request(options, function (res) {
-  console.log('STATUS: ' + res.statusCode);
-  console.log('HEADERS: ' + JSON.stringify(res.headers));
+  console.log('STATUS1: %d, %d ms', res.statusCode, Date.now() - start);
+  console.log('HEADERS1: %j', res.headers);
   res.setEncoding('utf8');
   res.on('data', function (chunk) {
-    console.log('BODY: ' + chunk);
+    console.log('BODY1: %d', chunk.length);
+  });
+  res.on('end', function () {
+    process.nextTick(function () {
+      start = Date.now();
+      https.get(options, function (res) {
+        console.log('STATUS2: %d, %d ms', res.statusCode, Date.now() - start);
+        console.log('HEADERS2: %j', res.headers);
+        res.setEncoding('utf8');
+        res.on('data', function (chunk) {
+          console.log('BODY2: %d', chunk.length);
+        });
+      });
+    });
   });
 });
 
@@ -26,7 +42,6 @@ req.on('error', function (e) {
 req.end();
 
 setTimeout(function () {
-  console.log('keep alive sockets:');
-  console.log(keepaliveAgent.unusedSockets);
+  console.log('keep alive sockets:', keepaliveAgent);
   process.exit();
-}, 2000);
\ No newline at end of file
+}, 5000);
diff --git a/lib/_http_agent.js b/lib/_http_agent.js
index c09bb82..a955e16 100644
--- a/lib/_http_agent.js
+++ b/lib/_http_agent.js
@@ -104,7 +104,7 @@ function Agent(options) {
           freeSockets = freeSockets || [];
           self.freeSockets[name] = freeSockets;
           socket.setKeepAlive(true, self.keepAliveMsecs);
-          socket.unref();
+          socket.unref && socket.unref();
           socket._httpMessage = null;
           self.removeSocket(socket, options);
           freeSockets.push(socket);
@@ -170,7 +170,7 @@ Agent.prototype.addRequest = function(req, options) {
     if (!this.freeSockets[name].length)
       delete this.freeSockets[name];
 
-    socket.ref();
+    socket.ref && socket.ref();
     req.onSocket(socket);
     this.sockets[name].push(socket);
   } else if (sockLen < this.maxSockets) {
diff --git a/package.json b/package.json
index f33da9f..9c9ad94 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "agentkeepalive",
-  "version": "0.1.5",
+  "version": "0.2.0",
   "description": "Missing keepalive http.Agent",
   "main": "index.js",
   "directories": {
@@ -32,6 +32,7 @@
     "coveralls": "*",
     "mocha-lcov-reporter": "*"
   },
+  "engines": { "node": ">= 0.10.0" },
   "author": "fengmk2 <fengmk2@gmail.com> (http://fengmk2.github.com)",
   "license": "MIT"
 }