Issue
Both fetch and XMLHttpRequest are adding an unwanted header transfer-encoding: chunked to any request with the method PUT on Windows only, macOS is fine.
Steps to reproduce
- make a
fetchrequest with methodPUT
Expected Behavior
No transfer-encoding header should be set, as the content-length is known
Actual Behavior
On Windows, transfer-encoding: chunked header is set.
On MacOS, no transfer-encoding header
Additional information
You can use https://webhook.site as an endpoint to test what headers the PUT request is sent with.
If it matters, I’m testing on the prerelease 21.0.25.1
It’s not possible to use fetch headers{} or setRequestHeader, as transfer-encoding is considered unsafe, so you are forbidden from setting it manually

