The documentation for the VSCode Rest Client is lacking good explinations. Here is what they give as an example.
POST https://api.example.com/user/upload
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="text"
title
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="image"; filename="1.png"
Content-Type: image/png
< ./1.png
------WebKitFormBoundary7MA4YWxkTrZu0gW--
Not sure what the <
is for nor the title
?