Enable setting auth type at request time.

[Stubbs]

Is your feature request related to a problem? Please describe.
In my app I am integrating with a forum and I want to be able to let users auth, but I also want to use an admin set of credentials to create forum threads as the site admin. The site admin uses client credentials and the normal users uses implicit grants (both OAth) so I need to be able to use tokens for users, but basic auth for the admin user, but I can only switch the auth type with config.

Describe the solution you'd like
Some kind of with function that mirrors withToken for auth ... withAuthScheme maybe.