udp服务信号是如何发送和接收

import { socket }  from '@kit.NetworkKit'; 
import { BusinessError } from '@kit.BasicServicesKit'; 
 
class SocketInfo { 
  message: ArrayBuffer = new ArrayBuffer(1); 
  remoteInfo: socket.SocketRemoteInfo = {} as socket.SocketRemoteInfo; 
} 
let udp: socket.UDPSocket = socket.constructUDPSocketInstance(); 
let messageView = ''; 
// 订阅UDPSocket连接的接收消息事件 
udp.on('message', (value: SocketInfo) => { 
  for (let i: number = 0; i < value.message.byteLength; i++) { 
    let uint8Array = new Uint8Array(value.message)  
    let messages = uint8Array[i] 
    let message = String.fromCharCode(messages); 
    messageView += message; 
  } 
  console.log('on message message: ' + JSON.stringify(messageView)); 
  console.log('remoteInfo: ' + JSON.stringify(value.remoteInfo)); 
}); 
// 绑定本地IP地址和端口。 
let bindAddr: socket.NetAddress = { 
  address: '192.168.xx.xxx', 
  port: 1234 
} 
udp.bind(bindAddr, (err: BusinessError) => { 
  if (err) { 
    console.log('bind fail'); 
    return; 
  } 
  let sendOptions: socket.UDPSendOptions = { 
    data: 'Hello, server!', 
    address: { 
      address: '192.168.xx.xxx', 
      port: 8080 
    } 
  } 
  // 发送数据 
  udp.send(sendOptions, (err: BusinessError) => { 
    if (err) { 
      console.log('send fail'); 
      return; 
    } 
    console.log('send success'); 
  }); 
  console.log('bind success'); 
}); 
 
// 关闭连接 
udp.close((err: BusinessError) => { 
  if (err) { 
    console.log('close fail'); 
    return; 
  } 
  console.log('close success'); 
})