How to use the @parcel/watcher.default function in @parcel/watcher

if (this.farm) {
      return;
    }

    await this.loadPlugins();

    if (!this.options.env) {
      await loadEnv(Path.join(this.options.rootDir, 'index'));
      this.options.env = process.env;
    }

    this.options.extensions = Object.assign({}, this.parser.extensions);
    this.options.bundleLoaders = this.bundleLoaders;

    if (this.options.watch) {
      this.watcher = new Watcher();
      // Wait for ready event for reliable testing on watcher
      if (process.env.NODE_ENV === 'test' && !this.watcher.ready) {
        await new Promise(resolve => this.watcher.once('ready', resolve));
      }
      this.watchedGlobs.forEach(glob => {
        this.watcher.add(glob);
      });
      this.watcher.on('add', this.onAdd.bind(this));
      this.watcher.on('change', this.onChange.bind(this));
      this.watcher.on('unlink', this.onUnlink.bind(this));
    }

    if (this.options.hmr) {
      this.hmr = new HMRServer();
      this.options.hmrPort = await this.hmr.start(this.options);
    }