/**
 * A Least Recently Used cache, implemented as an extended Map.
 */
export declare class LRUCache<K, V> extends Map<K, V> {
    readonly maxSize: number;
    constructor(maxSize?: number, entries?: Iterable<[K, V]>);
    get(key: K): V | undefined;
    set(key: K, value: V): this;
    first(): K | undefined;
}