anchor.diff:          }
           
           // Fall back to sending the entire content.
  -        file.openRead().pipe(response).catchError(_errorHandler);
  +        pipeToResponse(file.openRead(), response);
         }, onError: fileError);
       }, onError: fileError);
     }
  
positive.code: 
          String ext = extension(file.path);
          if (_extToContentType.containsKey(ext.toLowerCase())) {
            response.headers.contentType =
                ContentType.parse(_extToContentType[ext.toLowerCase()]);
          }
  
          if (request.method == 'HEAD') {
  
negative.code:   void addMIMETypes(Map<String, String> types){
      _extToContentType.addAll(types);
    }
    
    /**
     * Serve the file [file] to the [request]. The content of the file will be
     * streamed to the response. If a supported [:Range:] header is received, only
  