doh-csharp-6.task.md

@@ -23,8 +23,6 @@ class CallerInfo
 }
 ```
 
-:question:  :eyes:  :star:  :hand_with_index_and_middle_finger_crossed:  :muscle:  :kr:  :heart_eyes_cat:  :ok_hand: :speak_no_evil:  :bulb:  :exclamation:   
-
 ## 비동기 호출  
 
 ### async/await 예약어  
@@ -59,5 +57,63 @@ class AsyncAwaitTest
 }
 ```  
 
+```c#  
+
+class BCLAsyncTest //WebClient 비동기 호출 async/await 예제
+{
+    public static void Main()
+    {
+        AwaitDownloadString();
+
+        Console.ReadLine();
+    }
+
+    private static async void AwaitDownloadString()
+    {
+        WebClient wc = new WebClient();
+        wc.Encoding = Encoding.UTF8;
+
+        //DownloadStringAsync보다 더 간편하게 이용 가능.
+        string text = await wc.DownloadStringTaskAsync("http://www.naver.com");
+        Console.WriteLine(text);
+    }
+}  
+```  
+
+```c#  
+class BCLAsyncTest2 //TCP 서버 비동기 통신 예제
+{
+    public static void Main()
+    {
+        TcpListener listener = new TcpListener(IPAddress.Any, 11200);
+        listener.Start();
+
+        while (true)
+        {
+            //연결 요청을 받아들인다.
+            var client = listener.AcceptTcpClient();
+            ProcessTcpClient(client);
+        }
+    }
+
+    //NetworkStream 클래스의 ReadAsync와 WriteAsync를 이용하면 간단하게 비동기 통신 구현 가능
+    private static async void ProcessTcpClient(TcpClient client)
+    {
+        NetworkStream ns = client.GetStream();
+
+        byte[] buffer = new byte[1024];
+        int received = await ns.ReadAsync(buffer, 0, buffer.Length);
+
+        string txt = Encoding.UTF8.GetString(buffer, 0 ,received);
+
+        byte[] sendBuffer = Encoding.UTF8.GetBytes("Hello : " + txt);
+        await ns.WriteAsync(sendBuffer, 0, sendBuffer.Length);
+        ns.Close();
+    }
+}
+```  
+
+
+