Not able to access req inside the ApiClient

When I am sending out requests using the ApiClient I will have to set the request header based on the cookie values.

In line 18 of client.js you do

```
const client = new ApiClient();
```

So the `req` property of an `ApiClient` object is empty. Which means the request cookie or header info cannot be retrieve this way.

So is there a way to get around this problem?