[Possible Bug ?] URL::InputStreamOptions.withExtraHeaders seems to behave differently on windows and OSX

This isn’t a awful bug but it took me quite a while to figure out what was going wrong.

I’m creating an inputStream to call my API, something like this

//postOptions is just a member variable that sets the request to a POST request
std::unique_ptr<InputStream> inStream(updateStatsURL.createInputStream(
    postOptions.withExtraHeaders("AUTHTOKEN: " + accessToken + "\n" + 
                                  "username: " + username)));

When my server recieves the call from my windows machine, in the headers can be found


However when sending from OSX, my headers look like

"authtoken": "eyJhbGciOiJIUzI //'AUTHTOKEN' is now all lowercase.

Obviously this isn’t the hardest thing to account for server side, but unless lowercase headers is a requirement of OSX or something, seems like just a bug?