Set-Cookie Response header not in response.headers

[jdpagley]

Set-Cookie is not working with fetch.

//Response to POST request

HTTP/1.1 200 OK
X-Powered-By: Express
Content-Type: application/json; charset=utf-8
Content-Length: 113
ETag: W/"71-397a9ddd"
Set-Cookie: session=eyJ1c2VyIjp7Il9pZCI6IjE5MTlkamRrZCIsImZpcnN0TmFtZSI6Ikpvc2giLCJsYXN0TmFtZSI6IlBhZ2xleSIsImVtYWlsIjoiamRwYWdsZXlAZ21haWwuY29tIiwiY3JlYXRlZE9uIjoxNDMxMTQ4MTMxMjQ2fX0=; path=/
Set-Cookie: session.sig=ukSK6_n1uWqAbwEynmbLdtnASDo; path=/
Date: Sat, 09 May 2015 05:09:18 GMT
Connection: keep-alive

[dgraham]

The Set-Cookie header is on the forbidden header list:
https://fetch.spec.whatwg.org/#forbidden-response-header-name

Responses do not include forbidden headers:
https://fetch.spec.whatwg.org/#concept-filtered-response-basic