code: function logConfigFile(configFile, logger) {
    let message;
    if (process.env.WORKER_ID !== undefined) {
      message = `Worker ${process.env.WORKER_ID} uses configuration file: ${configFile}`;
    } else {
      message = `Supervisor uses configuration file: ${configFile}`;
    }
    if (logger && logger.verbose) {
      logger.verbose(message);
    } else {
      // eslint-disable-next-line no-console
      console.log(message);
    }
  }
docs: log config file usages