code: private function logRequestHeaders()
      {
          if (!$this->debug->getCfg('logEnvInfo.headers')) {
              return;
          }
          if (!empty($_SERVER['argv'])) {
              return;
          }
          $headers = $this->debug->utilities->getAllHeaders();
          \ksort($headers, SORT_NATURAL);
          $this->debug->log('request headers', $headers);
      }
docs: Log Request Headers
  
  @return void