code: protected function dumpString($val)
      {
          if (\is_numeric($val)) {
              $date = $this->checkTimestamp($val);
              return $date
                  ? $val.' ('.$date.')'
                  : $val;
          } else {
              return $this->debug->utf8->dump($val);
          }
      }
docs: Dump string
  
  @param string $val string value
  
  @return string