diff --git a/websocket-sharp/Net/ResponseStream.cs b/websocket-sharp/Net/ResponseStream.cs
index b48d4eec..c424fb41 100644
--- a/websocket-sharp/Net/ResponseStream.cs
+++ b/websocket-sharp/Net/ResponseStream.cs
@@ -202,7 +202,8 @@ namespace WebSocketSharp.Net
 
     private static byte[] getChunkSizeBytes (int size, bool final)
     {
-      return Encoding.ASCII.GetBytes (String.Format ("{0:x}\r\n{1}", size, final ? "\r\n" : ""));
+      var chunkSize = String.Format ("{0:x}\r\n{1}", size, final ? "\r\n" : "");
+      return Encoding.ASCII.GetBytes (chunkSize);
     }
 
     private void writeChunked (byte[] buffer, int offset, int count)