How to use the @angular-devkit/build-webpack.WebpackDevServerBuilder function in @angular-devkit/build-webpack

run(builderConfig) {
        const options = builderConfig.options;
        const root = this.context.workspace.root;
        const projectRoot = core_1.resolve(root, builderConfig.root);
        const host = new core_1.virtualFs.AliasHost(this.context.host);
        const webpackDevServerBuilder = new build_webpack_1.WebpackDevServerBuilder(Object.assign({}, this.context, { host }));
        let browserOptions;
        let first = true;
        let opnAddress;
        return check_port_1.checkPort(options.port, options.host).pipe(operators_1.tap((port) => options.port = port), operators_1.concatMap(() => this._getBrowserOptions(options)), operators_1.tap(opts => browserOptions = utils_1.normalizeBuilderSchema(host, root, opts)), operators_1.concatMap(() => {
            const webpackConfig = this.buildWebpackConfig(root, projectRoot, host, browserOptions);
            let webpackDevServerConfig;
            try {
                webpackDevServerConfig = this._buildServerConfig(root, options, browserOptions);
            }
            catch (err) {
                return rxjs_1.throwError(err);
            }
            // Resolve public host and client address.
            let clientAddress = `${options.ssl ? 'https' : 'http'}://0.0.0.0:0`;
            if (options.publicHost) {
                let publicHost = options.publicHost;

run(builderConfig) {
        const options = builderConfig.options;
        const root = this.context.workspace.root;
        const projectRoot = core_1.resolve(root, builderConfig.root);
        const host = new core_1.virtualFs.AliasHost(this.context.host);
        const webpackDevServerBuilder = new build_webpack_1.WebpackDevServerBuilder(Object.assign({}, this.context, { host }));
        let browserOptions;
        let first = true;
        let opnAddress;
        return check_port_1.checkPort(options.port, options.host).pipe(operators_1.tap((port) => options.port = port), operators_1.concatMap(() => this._getBrowserOptions(options)), operators_1.tap((opts) => browserOptions = opts), operators_1.concatMap(() => utils_1.normalizeFileReplacements(browserOptions.fileReplacements, host, root)), operators_1.tap(fileReplacements => browserOptions.fileReplacements = fileReplacements), operators_1.concatMap(() => utils_1.normalizeAssetPatterns(browserOptions.assets, host, root, projectRoot, builderConfig.sourceRoot)), 
        // Replace the assets in options with the normalized version.
        operators_1.tap((assetPatternObjects => browserOptions.assets = assetPatternObjects)), operators_1.concatMap(() => {
            const webpackConfig = this.buildWebpackConfig(root, projectRoot, host, browserOptions);
            let webpackDevServerConfig;
            try {
                webpackDevServerConfig = this._buildServerConfig(root, projectRoot, options, browserOptions);
            }
            catch (err) {
                return rxjs_1.throwError(err);
            }
            // Resolve public host and client address.
            let clientAddress = `${options.ssl ? 'https' : 'http'}://0.0.0.0:0`;

run(builderConfig: BuilderConfiguration): Observable {
    const options = builderConfig.options;
    const root = this.context.workspace.root;
    const projectRoot = resolve(root, builderConfig.root);
    const host = new virtualFs.AliasHost(this.context.host as virtualFs.Host);
    const webpackDevServerBuilder = new WebpackDevServerBuilder({ ...this.context, host });
    let browserOptions: NormalizedBrowserBuilderSchema;
    let first = true;
    let opnAddress: string;

    return from(checkPort(options.port || 0, options.host || 'localhost', 4200)).pipe(
      tap((port) => options.port = port),
      concatMap(() => this._getBrowserOptions(options)),
      tap(opts => browserOptions = normalizeBrowserSchema(
        host,
        root,
        resolve(root, builderConfig.root),
        builderConfig.sourceRoot,
        opts.options,
      )),
      concatMap(() => {
        const webpackConfig = this.buildWebpackConfig(root, projectRoot, host, browserOptions);