anchor.diff:        when: (http.BaseResponse response) => _responseIsAcceptable(response) == false,
         delay: (int attempt) => retryDelay ?? const Duration(seconds: 3) * attempt,
       );
  -    final http.Response response = await client.put(url, body: body);
  +    final http.Response response = await client.put(
  +      url,
  +      body: body,
  +      headers: <String, String>{
  +        // TODO(chillers): Remove once b/239021831 has been fixed by the GoB side.
  +        'X-Gerrit-Trace': 'bug-239021831-$branchName'
  +      },
  +    );
       if (_responseIsAcceptable(response) == false) {
         throw InternalServerError('Gerrit returned ${response.statusCode} which is not 200 or 202');
       }
  
positive.code:   Future<dynamic> _put(
      Uri url, {
      Object? body,
    }) async {
      final http.Client authClient = await authClientProvider(baseClient: httpClient, scopes: <String>[]);
      // GoB replicas may not have all the Flutter state, and can require several retries
  
negative.code:     String body = jsonEncode(<String, String>{
        'revision': revision,
      });
      final Map<String, dynamic> response = await _put(
        url,
        body: body,
        branchName: branchName,
      ) as Map<String, dynamic>;
      log.info(response);
      if (response['revision'] != revision) {
        throw const InternalServerError('Failed to create branch');
  