extend(opts) {
    return new StackLogger({...this.#store, ...(typeof opts === 'object' ? opts : {})});
  }
Opts to extend self with
@param {{}} [opts] Options
@param {number} [opts.indent] Indentation from 0 for this instance.
@param {any} [opts.indentor] Indentation fill for indentation range.
@param {number} [opts.indentSize] Size for subsequent instances created from self.