std::string HttpResponse::VALID_RESPONSE_HEADERS = ",access-control-allow-origin,access-control-allow-headers,access-control-allow-credentials,access-control-allow-methods,access-control-max-age,accept-ranges,age,allow,cache-control,connection,content-encoding,content-language,content-length,content-location,content-md5,content-disposition,content-range,content-type,date,etag,expires,last-modified,link,location,p3p,pragma,proxy-authenticate,refresh,retry-after,server,set-cookie,status,strict-transport-security,trailer,transfer-encoding,vary,via,warning,www-authenticate,";
