[Feature Request] Should we allow to specify custom headers for a part of a multipart request?

[MaryGao]

I notice that in swagger spec we allow to specify custom headers for a part of a multipart request, can we define a custom header in TypeSpec? https://swagger.io/docs/specification/describing-request-body/multipart-requests/

POST /upload HTTP/1.1
Content-Length: 428
Content-Type: multipart/form-data; boundary=abcde12345

--abcde12345
Content-Disposition: form-data; name="id"
Content-Type: text/plain

123e4567-e89b-12d3-a456-426655440000
--abcde12345
Content-Disposition: form-data; name="profileImage"; filename="image1.png"
Content-Type: image/png
X-Custom-Header: x-header

{…file content…}
--abcde12345--

/cc @lirenhe

[MaryGao]

I saw similar requirement in other repos and I would take this as real customer's needs.

• Set Custom Headers  form-data/form-data#83
• [Suggestion] Add more per-file (custom) header to multipart whatwg/fetch#1130
• post form-data not support customized headers postmanlabs/postman-app-support#8203