Update SpeedtestHandler.cs

v2rayN/v2rayN/Handler/SpeedtestHandler.cs

@@ -252,7 +252,7 @@ namespace v2rayN.Handler
 
             try
             {
-                IPHostEntry ipHostInfo = System.Net.Dns.Resolve(url);
+                IPHostEntry ipHostInfo = System.Net.Dns.GetHostEntry(url);
                 IPAddress ipAddress = ipHostInfo.AddressList[0];
 
                 var timer = new Stopwatch();