How to use the @salesforce/core.fs.stat function in @salesforce/core

// create a temp project so we can leverage force:source:convert for destructiveChanges

      let tmpDeleteProj: string;
      let tempDeleteProjConverted: string;
      if (hasDeletions) {
        tmpDeleteProj = await this.setupTmpProject(diffResults.removed, toBranch);
        tempDeleteProjConverted = await this.mkTempDir();
        await spawnPromise('sfdx', ['force:source:convert', '-d', tempDeleteProjConverted], { shell: true, cwd: tmpDeleteProj });
      }

      // create a temp project so we can leverage force:source:convert for primary deploy
      const tmpProject = await this.setupTmpProject(diffResults.changed, fromBranch);
      const outDir = isAbsolute(this.flags.outputdir) ? this.flags.outputdir : join(this.projectPath, this.flags.outputdir);
      try {
        const stat = await fs.stat(outDir);
        if (stat.isDirectory()) {
          let purge = false;
          if (this.flags.purge) {
            purge = true;
          } else {
            const resp = await this.ux.prompt(`The output path ${outDir} already exists.  How would you like to continue? (purge | merge | exit)`);
            if (resp.toLocaleLowerCase() === 'purge') {
              purge = true;
            } else if (resp.toLocaleLowerCase() !== 'merge') {
              this.exit(1);
              return;
            }
          }
          if (purge) {
            this.ux.log(`Removing all files inside of ${outDir}`);
            try {

let fetchedCount = 0;
    let fetchedCountPerObject = {};
    am.on('dumpProgress', status => {
      fetchedCount = status.fetchedCount;
      fetchedCountPerObject = status.fetchedCountPerObject;
      const perObjectCount = Object.keys(fetchedCountPerObject).map(object => `${object}: ${fetchedCountPerObject[object]}`).join(', ');
      const message = `fetched count: ${fetchedCount}, ${perObjectCount}`;
      this.ux.setSpinnerStatus(message);
    });
    this.ux.startSpinner('dumping records');
    const csvs = await am.dumpAsCSVData(config.targets);
    this.ux.stopSpinner();
    this.ux.log(`fetched count: ${fetchedCount}`);
    try {
      await fs.stat(config.outputDir);
    } catch (e) {
      await fs.mkdirp(config.outputDir);
    }
    const results = await Promise.all(
      config.targets.map(async ({ object }, i) => {
        const csv = csvs[i];
        const count = fetchedCountPerObject[object] || 0;
        const filename = `${object}.csv`;
        const filepath = path.join(config.outputDir, filename);
        const bom = this.flags.excludebom ? '' : '\ufeff';
        await writeFile(filepath, bom + csv, 'utf8');
        return { filepath, count };
      })
    );
    this.ux.log();
    this.ux.table(