This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
public interface UserInfoRestTemplateCustomizer
Callback for customizing the rest template used to fetch user details if authentication
is done via OAuth2 access tokens. The default should be fine for most providers, but
occasionally you might need to add additional interceptors, or change the request
authenticator (which is how the token gets attached to outgoing requests). The rest
template that is being customized here is only used internally to carry out
authentication (in the SSO or Resource Server use cases).