gzip 压缩的请求 body 乱码

Plese fill the template when you reporting a new issue, thanks!

#### Which platform are you running AnyProxy

Mac
#### The version of the AnyProxy

4.1.2

#### Your expected behavior of AnyProxy

哔哩哔哩App，可以查看 https://dataflow.biliapi.com/log/pbmobile/unrealtime?ios 的请求 body
#### The actual behavior of AnyProxy

https://dataflow.biliapi.com/log/pbmobile/unrealtime?ios 的请求 body 乱码

Charles 虽然也有部分乱码，但关键信息可以看到

应该是因为请求头里有 `Content-Encoding :
gzip`，在规则文件里解压后输出到控制台的内容就和 Charles 一样了，请教一下怎么处理才能在UI界面正常显示
```javascript
* beforeSendRequest(requestDetail) {
zlib.gunzip(requestDetail.requestData, function (error, result) {
if (error) throw error
console.log(result)
console.log(result.toString())
})
return newRequest
}
```

Start with the beforeSendRequest rule and its zlib.gunzip example, then trace how the gzip-encoded request body is passed to the UI. Compare the displayed body with the decoded output for the reported Bilibili request. Done means the UI shows readable content for gzip-compressed request bodies.

Written by the indexing model from the issue text.