import { EventEmitter } from "events";
import { Request } from "../request";
import { Heap } from './heap';
import { TimeoutHandler } from './timeout-handler';
export declare class PriorityQueue extends EventEmitter {
    private readonly queue;
    private readonly timeoutHandler;
    private readonly timers;
    private lastTimeEmpty;
    private _entryRequests;
    private _exitRequests;
    private logger;
    constructor(queue: Heap<Request<any>>, timeoutHandler: TimeoutHandler);
    add(request: Request<any>): void;
    poll(): Request<any> | null;
    resetCounters(): void;
    private scheduleTimeoutRemoval;
    private setLastTimeEmpty;
    getSecondsSinceLastEmpty(): number;
    get entryRequests(): number;
    get exitRequests(): number;
    isEmpty(): boolean;
    get length(): number;
    private clearTimer;
}