/** Extension → content type, shared by this server and the generated Swift handler. */
export declare const MIME_TYPES: ReadonlyMap<string, string>;
export declare const FALLBACK_MIME = "application/octet-stream";
export declare function mimeTypeFor(filePath: string): string;
export interface PayloadServer {
    port: number;
    origin: string;
    close: () => Promise<void>;
}
/** Serve `dir` on an ephemeral localhost port. */
export declare function startPayloadServer(dir: string): Promise<PayloadServer>;