code: function handle(route, file) {
    route.status = 'starting';
    route.emit('handle', file);
  
    for (let layer of route.stack) {
      route.emit('layer', layer, file);
      layer.handle(file);
    }
  
    route.status = 'finished';
    route.emit('handle', file);
    return file;
  }
docs: Sync method, used when options.sync is true