if ($log->is_trace) {
    require Data::Dumper;
    $log->debugf('Method:  %s', $method);
    $log->debugf('URL: %s', $url);
    $log->debugf('Headers: %s', Data::Dumper::Dumper( $headers ));
    $log->debugf('Data:    %s', Data::Dumper::Dumper( $data ));
  }