pkg/shelf: Fixed logic for setting Server header in `shelf_io`

pkg/shelf/lib/shelf_io.dart

Index: pkg/shelf/lib/shelf_io.dart
diff --git a/pkg/shelf/lib/shelf_io.dart b/pkg/shelf/lib/shelf_io.dart
index 1bd4f5164def2a8d6d6dd6b390bf8087d0141355..35efe4573334817f1dcc58b8d166d50095a13f9d 100644
--- a/pkg/shelf/lib/shelf_io.dart
+++ b/pkg/shelf/lib/shelf_io.dart
@@ -87,10 +87,6 @@ Future _writeResponse(Response response, HttpResponse httpResponse) {
     httpResponse.headers.set(header, value);
   });
 
-  if (response.headers[HttpHeaders.SERVER] == null) {
-    var value = httpResponse.headers.value(HttpHeaders.SERVER);
-    httpResponse.headers.set(HttpHeaders.SERVER, '$value with Shelf');
-  }

[nweiz, 2014/05/15 22:21:32]

I still like the intent of this code, even if it didn't work correctly. Can you
figure out how dart:io's server computes its default header and use the same
logic here?

   return httpResponse.addStream(response.read())
       .then((_) => httpResponse.close());
 }