Implement RP-initiated logout in the client stack

[kevinchalet]

Confirm you've already contributed to this project or that you sponsor it

• [X] I confirm I'm a sponsor or a contributor

Describe the solution you'd like

https://openid.net/specs/openid-connect-rpinitiated-1_0.html#RPLogout

Additional context

No response

[feededit]

Velusia.Server is the old version and Velusia.Client is the new version.

return SignOut(CookieAuthenticationDefaults.AuthenticationScheme, OpenIdConnectDefaults.AuthenticationScheme);

How does signout() work?

[feededit]

When will you complete adding logout support in the client?

[kevinchalet]

@feededit support will be available in the next preview.