default void expect(IdlToken token) {
        if (getCurrentToken() != token) {
            throw LoaderUtils.idlSyntaxError(LoaderUtils.idlExpectMessage(this, token), getCurrentTokenLocation());
        }
    }
Assert that the current token is {@code token}.

<p>The tokenizer is not advanced after validating the current token.</p>

@param token Token to expect.
@throws ModelSyntaxException if the current token is unexpected.
smithy-model/src/main/java/software/amazon/smithy/model/loader/IdlTokenizer.java