/** Build a single-file multipart/form-data payload for app.inject() tests.
 *  One shared encoding so a fix to quoting/CRLF handling reaches every route
 *  test that exercises @fastify/multipart parsing. */
export declare function multipartPayload(params: {
    boundary: string;
    filename: string;
    contentType: string;
    bytes: Buffer;
}): Buffer;
