Deferring the upload length of resumable streams

Hi!

I’m trying to upload the output of MediaRecorder chunks on the browser. Since it isn’t ended I can’t know the final size of the recording, so I found that Upload-Defer-Length: 1 header in TUS protocol specification but I get a CORS error when I sent a request with that header.

You can reproduce the issue easily with tus-js-client > demos > browser > video (sorry I can’t add link in my post)

Does CF stream support deferred length or am I missing something?