public SamlServiceProviderBuilder authorizer(Authorizer<HttpRequest> authorizer) {
        this.authorizer = requireNonNull(authorizer, "authorizer");
        return this;
    }
Set an {@link Authorizer} which is used for this service provider's authentication.
saml/src/main/java/com/linecorp/armeria/server/saml/SamlServiceProviderBuilder.java