I need to send a POST request to a site passing URL encoded form data. For that, I have to pass a Content-Type HTTP header with application/x-www-form-urlencoded value. In 0.4.0, I have to use a HttpHeaders model for headers parameter of Request.from_url() method to make type checker happy. However, this model is defined in crawlee._types module which seems to be a private module (at least that's the usual intent communicated with underscored module name). I guess it would be best if HttpHeaders was exported directly from a crawlee package.