anchor.diff:      passHeaders['host'] = _newHost;
       _logProxyRequest.finest('[${req.id}] + host=$_newHost');
   
  -    // Identify any connection headers that must not be passed through
  +    // Identify any link-only headers that must not be passed through.
  +    // These are identified in the "Connection" header, if any.
   
       // ignore: prefer_collection_literals
       final requestConnectionExclude = Set<String>();
  
positive.code:       final headerValue = targetResponse.headers[key];
  
        if (responseHeadersNeverPass.contains(headerName) ||
            responseConnectionExclude.contains(headerName.toLowerCase()) ||
            (responseBlockHeaders.contains(headerName)) ||
            headerName == 'via') {
          // Do not pass back header
          _logProxyResponse.finest('[${req.id}] - $headerName=$headerValue');
        } else {
  
negative.code:     final resp = ResponseStream(contentType)
        ..status = targetResponse.statusCode
        ..headerRemoveAll();
  
      assert(resp.headerNames().isEmpty);
  
      // Add connection close header to indicate connection will not persist
  
      resp.headerAdd('connection', 'close');
      _logProxyResponse.finest('[${req.id}] + connection=close');
  
      // Above removes all default headers, since some/all of them might be
      // present in the proxy response. Only the ones from the proxy response will
  