const express = require('express');
const fs = require('fs');
const path = require('path');
const app = express();
app.get('/', function(req, res) {
res.sendFile(path.join(__dirname + '/index.html'));
})
app.get('/audio', function(req, res) {
const path = 'sample.mp3';
const stat = fs.statSync(path);
const fileSize = stat.size;
const range = req.headers.range;
if (range) {
const parts = range.replace(/bytes=/, '').split('-');
const start = parseInt(parts[0], 10);
const end = parts[1] ? parseInt(parts[1], 10) : fileSize - 1;
const chunksize = (end-start) + 1;
const file = fs.createReadStream(path, {start, end});
const head = {
'Content-Range': `bytes ${start}-${end}/${fileSize}`,
'Accept-Ranges': 'bytes',
'Content-Length': chunksize,
'Content-Type': 'audio/mpeg',
};
res.writeHead(206, head);
file.pipe(res);
} else {
const head = {
'Content-Length': fileSize,
'Content-Type': 'audio/mpeg',
};
res.writeHead(200, head);
fs.createReadStream(path).pipe(res);
}
});
app.listen(8000, function () {
console.log('Listening on port 8000!');
});fs.createReadStream(path).pipe(res);. Пожалуйста помогите решить проблему. 
const Koa = require('koa');
const Router = require('koa-router');
const fs = require('fs');
const { promisify } = require('util');
const fsStat = promisify(fs.stat).bind(fs);
const app = Koa();
const router = new Router();
router.get('/audio', async (context) => {
const path = 'sample.mp3';
const { size: filesize } = await fsStat(path);
const range = context.get('range');
context.type = 'audio/mpeg';
if (!range) {
context.length = filesize;
context.body = fs.createReadStream(path);
return;
}
const [startPart, endPart] = range.replace(/bytes=/, '')
.split('-');
const start = parseInt(startPart, 10);
const end = endPart
? parseInt(endPart, 10)
: filesize - 1;
context.length = (end - start) + 1;
context.status = 206;
context.set({
'Accept-Ranges': 'bytes',
'Content-Range': `bytes ${start}-${end}/${filesize}`
});
context.body = fs.createReadStream(path, {
start,
end
});
});
app
.use(router.routes())
.use(router.allowedMethods());
app.listen(8000, () => {
console.log('Listening on port 8000!');
});
Простой