public void Callback() { AsyncHttpClient asyncHttpClient = new AsyncHttpClient(); var request = new HttpRequest(); request.Uri = new Uri("http://www.w3school.com.cn"); var html = asyncHttpClient.GetString(request); TestContext.WriteLine(html); var count = 0; var testCount = 100; for (int i = 0; i < testCount; i++) { asyncHttpClient.Execute(request, (res) => { res.BodyStream.ReadAsString((str) => { TestContext.WriteLine("thread id:" + Thread.CurrentThread.ManagedThreadId); lock (this) { count++; } }); }); } while (count != testCount) { Thread.Sleep(10); } }