websocket close하다가 null되는 현상처리(2일째에서 발생)

Million/Manager/RealtimeDataSettingManager.cs

@@ -217,22 +217,22 @@ namespace Million.Manager
             while (Flag)
             {
                 ClientWebSocket webSocket = new ClientWebSocket();
-
+                var cancelToken = CancellationToken.None;
                 try
                 {
-                    await webSocket.ConnectAsync(new Uri(WebSocketUrl), CancellationToken.None);
+                    await webSocket.ConnectAsync(new Uri(WebSocketUrl), cancelToken);
                     var dic = new List<Dictionary<string, object>>();
                     dic.Add(new Dictionary<string, object>() { { "ticket", "test" } });
                     dic.Add(new Dictionary<string, object>() { { "type", "trade" }, { "codes", CommonProperty.recentlyMarketOfPlaceList.Where(t => t.CoinFullName.Contains("KRW-")).Select(t => t.CoinFullName).ToList() } });
 
                     await SendMessage(webSocket, JsonConvert.SerializeObject(dic));
 
-
+                    
                     // 데이터 수신을 위한 반복문 시작
                     while (webSocket.State == WebSocketState.Open && Flag)
                     {
                         byte[] buffer = new byte[1024 * 10];
-                        WebSocketReceiveResult result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
+                        WebSocketReceiveResult result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), cancelToken);
 
                         // 수신한 데이터 처리
                         message = System.Text.Encoding.UTF8.GetString(buffer, 0, result.Count);
@@ -265,11 +265,20 @@ namespace Million.Manager
                 finally
                 {
                     if (webSocket.State == WebSocketState.Open)
-                    {                        
-                        await webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, webSocket.CloseStatusDescription, CancellationToken.None);
-                    }                     
-
-                    webSocket.Dispose();
+                    {
+                        try
+                        {
+                            await webSocket.CloseAsync(webSocket.CloseStatus.Value, webSocket.CloseStatusDescription, cancelToken);                            
+                        }
+                        catch (Exception e)
+                        {
+                            LogManager.WriteLog(e.Message + "\r\n오류 메세지 : " + message);
+                        }
+                        if(webSocket != null)                        
+                            webSocket.Dispose();
+                            
+                        webSocket = null;
+                    }
                 }
             }
         }