/**
 * Serialize FormData to a multipart/form-data Blob.
 *
 * This is the equivalent of formdata-polyfill's formDataToBlob().
 * Used by the Body mixin to convert FormData bodies for transmission.
 */
import type { FormData } from './formdata.ts';
/**
 * Converts a FormData instance into a Blob with multipart/form-data content type.
 */
export declare function formDataToBlob(formData: FormData, boundary?: string): Blob;