protected static void parseOptionalValueAssignment(CapturingTokenizer tokenizer) {
        if (tokenizer.peekPastSpaces().getIdlToken() == IdlToken.EQUAL) {
            VALUE_ASSIGNMENT.parse(tokenizer);
        }
    }
The innermost node of the token tree that contains an actual token returned from {@link IdlTokenizer}.
smithy-syntax/src/main/java/software/amazon/smithy/syntax/TreeType.java