Remove redundant redirect count check: CURLINFO_REDIRECT_COUNT is only non-zero when CURLOPT_FOLLOWLOCATION is enabled but we track redirects ourselves since 692e8bc.

Remove redundant url setting: Since starting to handle redirects ourselves in 692e8bc, url info item (aka CURLINFO_EFFECTIVE_URL) will be the same as the initial URI.

Remove redundant status_code setting: In fact, when the server sends interim responses, this was counterproductive – it would overwrite the final response code returned by CURLINFO_HTTP_CODE with the interim one (e.g. 100). Though, the parser will still include the headers of all but the first response in the body.

Avoid truthiness conversion of curl_errno: Explicit comparison is clearer than relying on CURLE_OK being falsey (0).

Replace redundant string cast with assertion: This is only needed for PHPStan. Making the type assertion explicit and moving it earlier will allow us to make the prepareHeaders call conditional without having to add more casts.

Make “header preparation” conditional: The method call was introduced in 4b1fc33 to support tunneling through HTTP proxy using CONNECT method, whose response curl includes in the curl_exec result. Ideally, we would prevent that with CURLOPT_SUPPRESS_CONNECT_HEADERS but that is only available in PHP 7.3.