[Modify] Add it

websocket-sharp/Net/HttpListenerRequest.cs

@@ -628,6 +628,13 @@ namespace WebSocketSharp.Net
       return ret;
     }
 
+    private RequestStream getInputStream ()
+    {
+      return _contentLength > 0 || _chunked
+             ? _connection.GetRequestStream (_contentLength, _chunked)
+             : null;
+    }
+
     #endregion
 
     #region Internal Methods