code: protected function getServerStats($pattern = '')
      {
          $stats = (array) $this->getPheanstalk()->stats();
  
          if (! empty($pattern)) {
              $stats = array_filter($stats, function ($key) use ($pattern) {
                  return 1 === preg_match("/$pattern/i", $key);
              }, ARRAY_FILTER_USE_KEY);
          }
  
          ksort($stats);
  
          return $stats;
      }
docs: Lists server statistics optionaly filtering keys by a pattern.
  
  @param string $pattern
  
  @return array