import type { Request, Response, NextFunction, Express } from 'express';
export declare const pressureReason: unique symbol;
export declare const pressureType: unique symbol;
export declare const TYPE_EVENT_LOOP_DELAY = "eventLoopDelay";
export declare const TYPE_HEAP_USED_BYTES = "heapUsedBytes";
export declare const TYPE_RSS_BYTES = "rssBytes";
export declare const TYPE_EVENT_LOOP_UTILIZATION = "eventLoopUtilization";
interface MiddlewareOptions {
    disableCheck?: boolean;
    maxEventLoopDelay?: number;
    maxEventLoopUtilization?: number;
    maxHeapUsedBytes?: number;
    maxRssBytes?: number;
    retryAfter?: number;
    message?: string;
    sampleInterval?: number;
    pressureHandler?: (request: Request, response: Response, next: NextFunction) => unknown;
}
export declare function underPressure(app: Express, opts?: MiddlewareOptions): void;
export {};