Default downloader used - handles downloading from all schemes specified in the gateway URLs configuration.
Example
// Can instantiate the downloader with the default gateway URLsconst downloader = newStorageDownloader();
// client id if used in client-side applicationsconst clientId = "your-client-id";
const storage = newThirdwebStorage({ clientId, downloader });
// secret key if used in server-side applicationsconst secretKey = "your-secret-key";
const storage = newThirdwebStorage({ secretKey, downloader });