docs: function _log(message) {
      if (cluster.isMaster) {
          // write directly to the log file
          console.log(_format(message));
      }
      else {
          // send to master
          cluster.worker.process.send({
              type: "logging",
              data: {
                  message: message,
                  workerID: cluster.worker.id,
                  pid: cluster.worker.process.pid
              }
          });
      }
  }