default CharSequence getModel(int start, int end) {
        return CharBuffer.wrap(getModel(), start, end);
    }
Get a borrowed slice of the model being tokenized.

@param start Start position to get, inclusive.
@param end   End position to stop at, exclusive.
@return Returns the slice.
smithy-model/src/main/java/software/amazon/smithy/model/loader/IdlTokenizer.java