code: public function getLoggedContent($logFile)
      {
          if (!array_key_exists($logFile, $this->ranges)) {
              throw new Exception('Invalid log file');
          }
  
          return $this->getContent(
              $this->getLogFilePath($logFile),
              $this->ranges[$logFile]['start'],
              $this->ranges[$logFile]['end']
          );
      }
docs: Returns content added during this request for specified log file
  
  @param string $logFile
  @return string
  @throws Exception