/** A map is an abstract data-type. See the wikipedia for more info: https://en.wikipedia.org/wiki/Associative_array
*
 FAQ:
* Why are the methods for map async?
* The methods are async so we can store the map in redis or a similar cache if we want to
* which will then make the URL-frontier more easily distributable across machines.
*/
export declare class AsyncMap<T, U> {
    #private;
    /** This method allows one to put into the map. */
    put(key: T, value: U): Promise<void>;
    /** This method allows one to take from the map. */
    take(item: T): Promise<U>;
    has(item: T): Promise<boolean>;
    /** This method creates a queue from an Iterable.
     * It is async because the items take time to enqueue
     **/
    static from<T, U>(items: Iterable<[T, U]>): Promise<AsyncMap<T, U>>;
}
//# sourceMappingURL=AsyncMap.d.ts.map