发送到客户端后无法设置头部，NodeJs错误

const http = require('http');

const server = http.createServer((req, res) => {
  res.setHeader('Content-Type', 'text/plain');
  // 其他头部设置...
  
  // 先设置好头部，然后发送主体内容
  res.write('Hello, World!');
  res.end();
});

server.listen(3000, () => {
  console.log('Server is running on port 3000');
});

const http = require('http');

const server = http.createServer((req, res) => {
  if (res.headersSent) {
    console.log('Cannot set headers after they are sent to the client');
    return;
  }
  
  // 设置头部
  res.setHeader('Content-Type', 'text/plain');
  // 其他头部设置...
  
  // 发送主体内容
  res.write('Hello, World!');
  res.end();
});

server.listen(3000, () => {
  console.log('Server is running on port 3000');
});