Client doesn't support passing arbitrary header in request header

[snoby]

As the code is written now, it doesn't seem that there is support for placing a key value field in the request header. For my use case I'm going through a SSOProxy that requires me to have a header 'Cookie': 'access_token=blahfooblah' access_token in the https header. Is there another way to add a header that I'm missing in the code?

Would it be 'correct' to add the arbitrary header to the config structure then, if that field has a value, add it to the req headers in all the different methods? Or is this considered an API change?