code: function spawnBuild(argv, skyPagesConfig, webpack) {
  
    if (argv.build === false) {
      logger.info('Skipping build step');
  
      const file = 'dist/metadata.json';
      if (!fs.existsSync(file)) {
        logger.info(`Unable to skip build step.  "${file}" not found.`);
      } else {
        return Promise.resolve({
          metadata: fs.readJsonSync(file)
        });
      }
    }
  
    return build(argv, skyPagesConfig, webpack)
      .then(stats => stats.toJson().chunks);
  }
docs: Spawns the build process.  Captures the config used.