/**
 * JSON file output plugin.
 *
 * Assembles the BenchmarkData structure from all upstream plugin data
 * and writes it to a JSON file. Returns the BenchmarkData for backward compat.
 */
import type { Middleware, MiddlewareContext, MiddlewareStore, SDKMessage } from '../types';
import type { BenchmarkData } from '../benchmark';
export declare class JsonWriterPlugin implements Middleware {
    readonly name = "jsonWriter";
    private outputPath;
    constructor(outputPath: string);
    onFinalize(resultMessage: SDKMessage, totalDurationMs: number, ctx: MiddlewareContext, _store: MiddlewareStore): BenchmarkData;
    private writeBenchmarkData;
}
