text: const dgram = require('dgram')
  const server = dgram.createSocket('udp4')
  
  server.on('error', err => {
      console.log(`服务器异常: \n${err.stack}`)
      server.close()
  })
  
  server.on('message', (msg, rinfo) => {
      console.log(`服务器收到: ${msg}来自${rinfo.address}:${rinfo.port}\n${rinfo.family}`)
  })
  
  server.on('listening', () => {
      const address = server.address()
      console.log(`服务器监听${address.address}:${address.port}`)
      const client = dgram.createSocket('udp4')
      client.send('test', 41234, 'localhost', err => {
          console.log(err)
      })
  })
  
  server.bind(41234)