constructor(config) {
        super();

        this.addPrefixSpace = config.add_prefix_space;
        this.replacement = config.replacement;
        this.strRep = config.str_rep || this.replacement;
        this.prepend_scheme = config.prepend_scheme ?? 'always';
    }
@param {Object} config The configuration object for the MetaspacePreTokenizer.
@param {boolean} config.add_prefix_space Whether to add a prefix space to the first token.
@param {string} config.replacement The character to replace spaces with.
@param {string} [config.str_rep=config.replacement] An optional string representation of the replacement character.
@param {'first'|'never'|'always'} [config.prepend_scheme='always'] The metaspace prepending scheme.