code: function serializeWorker(worker) {
    return {
      id: worker.id,
      up: worker.up,
      lastCallDuration: worker.lastCallDuration,
      meanCallDuration: worker.meanCallDuration,
      host: worker.host,
      port: worker.port,
      type: worker.type
    }
  }
docs: Skip properties we don't need to share (like interval ID).