POST /batch/gmail/v1 HTTP/1.1^M
Accept-Encoding: gzip^M
Host: www.googleapis.com^M
User-Agent: Mojolicious (Perl)^M
Content-Length: 120^M
Content-Type: multipart/mixed; boundary=WHeuX^M
Authorization: Bearer REAL_TOKEN^M
^M
--WHeuX^M
Content-Type: application/http^M
^M
GET /gmail/v1/users/my_real_email@gmail.com/messages/165eb111fcf21503^M
--WHeuX--^M