Describe the bug
When using the ExecuteJavascriptMiddleware, two requests are sent. One by Browsershot, the other by Guzzle.

Reproduction
My spider only has the ExecuteJavascriptMiddleware registered as downloader middleware.

I placed dumps with the request object id in the following places, just before requests are sent:

RoachPHP\Http\Client

RoachPHP\Downloader\Middleware\ExecuteJavascriptMiddleware

When the spider runs, both dumps are shown:

Expected behavior
I was expecting only one request being sent: one from Browsershot, not also one from Guzzle.

Package versions (please complete the following information):

• core: v3.0.1