Add support for Kestrel return non-ASCII headers in response

[yunfandev]

Describe the bug

When I try to create a reverse proxy using asp.net core with the library reverse-proxy for my blog, which has the following response header:

access-control-allow-credentials: true
access-control-allow-origin: *
cache-control: public, max-age=0
content-encoding: gzip
content-type: text/html; charset=utf-8
date: Fri, 25 Sep 2020 10:15:43 GMT
etag: W/"9127-u+4Jv+RfD2erbftmcMqr2DT5eig"
status: 304
strict-transport-security: max-age=315360000; includeSubDomains; preload
vary: Origin
x-powered-by: traefik(made with ❤️ with go)

It throws an expectation, InvalidOperationException: Invalid non-ASCII or control character in header: 0x00E2 😂😂😂

To Reproduce

Set any non-ASCII header in the response.

Exceptions (if any)

InvalidOperationException: Invalid non-ASCII or control character in header: 0x00E2

Further technical details

.NET Core SDK (reflecting any global.json):
Version:   3.1.402
Commit:    9b5de826fd

Runtime Environment:
OS Name:     Windows
OS Version:  10.0.19042
OS Platform: Windows
RID:         win10-x64

[yunfandev]

Origin issue: dotnet/yarp#440

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[blowdart]

If we do this, it needs to be off by default, because, as we all known, that is, as the error indicates, an illlegal header, which should be rejected.

[yunfandev]

@blowdart

Agree. As long as it can be manually turned on when needed.

[yunfandev]

It looks like there is already a similar issue: Allow non-ASCII characters in response header values

[davidfowl]

Closing as dupe