text: 'use strict';
  const cluster = require('cluster');
  const express = require('express');
  const app = express();
  const PORT = process.env.PORT || 8080;
  const numCPUs = require('os').cpus().length;
  
  if (cluster.isMaster) {
    // Fork workers.
    for (let i = 0; i < numCPUs; i++) {
      cluster.fork();
    }
  } else {
    app.get('/api/test', (req, res) => {
      res.type('text/plain');
      res.send('Hello, World!');
    });
  
    app.listen(PORT, () => console.log('Server start listen port: ' + PORT));
  }
  