Expand description
multipart/form-data bodies, with the API of reqwest’s multipart module that generated clients use.
A form whose parts are all held in memory encodes to a body held in memory, so a retry layer can send it again.
A form with a streamed part encodes to a stream; when every part can be sent again (bytes, a file
Upload), a retry makes that stream again, opening the files afresh. When the length of every part is known
(bytes, a resolved file), the form is sent with a Content-Length instead of chunked.