/**
 * Fetches a file from the given URL and returns it as a buffer.
 * @param url The URL to fetch the file from.
 * @param fallbackMimeType Fallback MIME type to use if the response headers do not contain a MIME type.
 * @returns The file as a buffer and its MIME type.
 */
export declare function fetchFileAsBuffer(url: string, fallbackMimeType?: string): Promise<{
    buffer: Buffer;
    mimeType: string;
}>;