export default class TrackSet<A> extends Set<A> {
    private subs;
    constructor(subs?: Set<Sub<A>>);
    add(a: A): this;
    delete(a: A): boolean;
    track(sub: Sub<A>): void;
    untrack(sub: Sub<A>): void;
    clear(): void;
}
declare type Sub<A> = (a: TrackSet<A>) => void;
export {};