code: private function reload()
      {
          $this->logger->info('Recieved SIGHUP signal.');
          $test = $this->spawnRpqInstance(true);
  
          if ($test === true) {
              $this->logger->debug('Self test passes. Running graceful shutdown sequence.');
              $pid = $this->spawnRpqInstance(false);
              $this->logger->info('New RPQ process has been started.', [
                  'pid' => $pid
              ]);
          } else {
              $this->logger->debug('Self test failed. Aborting reload.');
              $this->dispatcher->setIsRunning(true);
          }
  
          return null;
      }
docs: Graceful reload
  
  Runs a self test to verify that the new RPQ configuration is valid.
  If the configuration is valid, RPQ will spawn a new RPQ instance to begin job processing
  If the configuration is not valid, RPQ will report the error and will continue processing jobs
  
  @return integer