视频流返回前端无法播放
### Discussed in https://github.com/eggjs/egg/discussions/4767

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<sup>Originally posted by **liyang9331** September 27, 2021</sup>
```js
ctx.set('content-type', 'video/mp4');//设置返回类型
    let stream = fs.createReadStream('./assets/test.mp4');
    if (stream) {//判断状态
      stream.on('open', function () {
        console.log('文件打开')
      });
      stream.on('end', function () {
        console.log("读取完毕")
      })
      stream.on('data', function (data) {
        // console.log("读取文件流")
        ctx.body = data
      })
      stream.on('err', function () {
        console.log("发生错误")
      })
      stream.on('close', function () {
        console.log('关闭')
        // ctx.end
      });
    }
```
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