export interface XlsxSource {
    /**
     * Resolve the full payload as a single Uint8Array. Memory-bounded; acceptable
     * for all xlsx parts up to ~hundreds of MB. For larger payloads use {@link
     * toStream}.
     */
    toBytes(): Promise<Uint8Array>;
    /**
     * Sequential byte stream. Optional — implementations that have no cheap
     * streaming representation may omit it. Consumers should fall back to {@link
     * toBytes} when undefined.
     */
    toStream?(): ReadableStream<Uint8Array>;
}