I’m developing a simple Node.js web server and I’m having some trouble handling concurrent requests. My server needs to perform the following tasks:

1. Serve a welcome message at the root URL (/).

2. Perform a long-running computation without blocking other requests at the URL (/long-task).

3. Read and return the contents of a file asynchronously at the URL (/read-file).

4. Handle 404 errors for unknown routes.

Requirements:

• The server should handle multiple requests concurrently without blocking the main thread.

• Use asynchronous APIs provided by Node.js to achieve non-blocking I/O operations.

• Properly handle errors and edge cases (e.g., file not found, server errors).

const fs = require('fs'); const http = require('http');  // Function to simulate a long-running task function longRunningTask(callback) {   setTimeout(() => {     callback('Long-running task completed');   }, 3000); // Simulate a task that takes 3 seconds }  // Function to read a file asynchronously function readFileAsync(filePath, callback) {   fs.readFile(filePath, 'utf8', (err, data) => {     if (err) {       callback(err);     } else {       callback(null, data);     }   }); }  // Create an HTTP server const server = http.createServer((req, res) => {   if (req.url === '/') {     res.writeHead(200, { 'Content-Type': 'text/plain' });     res.end('Hello, world!n');   } else if (req.url === '/long-task') {     longRunningTask((message) => {       res.writeHead(200, { 'Content-Type': 'text/plain' });       res.end(message + 'n');     });   } else if (req.url === '/read-file') {     readFileAsync('example.txt', (err, data) => {       if (err) {         res.writeHead(500, { 'Content-Type': 'text/plain' });         res.end('Error reading filen');       } else {         res.writeHead(200, { 'Content-Type': 'text/plain' });         res.end(data);       }     });   } else {     res.writeHead(404, { 'Content-Type': 'text/plain' });     res.end('Not Foundn');   } });  // Start the server server.listen(3000, () => {   console.log('Server is listening on port 3000'); });