export declare class WeakRefSet<T extends {}> implements Set<T> {
    readonly onItemCleaned?: () => void;
    constructor(onItemCleaned?: () => void);
    private _set;
    private _map;
    private _registry;
    get size(): number;
    [Symbol.toStringTag]: string;
    protected _size(): number;
    add(value: T): this;
    clear(): void;
    delete(value: T): boolean;
    forEach(callbackfn: (value: T, value2: T, set: Set<T>) => void, thisArg?: any): void;
    has(value: T): boolean;
    values(): IterableIterator<T>;
    entries(): IterableIterator<[T, T]>;
    keys(): IterableIterator<T>;
    [Symbol.iterator](): IterableIterator<T>;
}