text: let cluster = require('cluster');
  let http = require('http');
  if (cluster.isMaster) {//如果此代码是在主进程中运行的话
      let worker = cluster.fork();
      cluster.on('fork', function () {
          console.log('开始fork');
      });
      cluster.on('online', function () {
          console.log('online 子进行已经启动成功了');
      });
      cluster.on('listening', function () {
          console.log('listening 子进程的服务器已经启动成功了，可以开始监听客户端请求了');
      });
      console.log('father');
  } else if (cluster.isWorker) {
      http.createServer(function (req, res) {
          res.end('worker data');
      }).listen(8080);
      console.log('worker');
  }