ParseKey converts the binary contents of a private key file to an *rsa.PrivateKey.

RegisterBrokenAuthHeaderProvider previously did something.

ResetAuthCache resets the global authentication style cache used for AuthStyleUnknown token requests.

HTTPClient is the context key to use with golang.org/x/net/context's WithValue function to associate an *http.Client value with a context.

ContextKey is just an empty struct.

Token represents the credentials used to authorize the requests to access protected resources on the OAuth 2.0 provider's backend.

AuthStyle is a copy of the golang.org/x/oauth2 package's AuthStyle type.