/**
 * A set of string ids, which can be lazy-loaded and iterated over.
 */
export declare class IdSet {
    private _backingSet;
    private readonly _getBackingSet;
    /**
     * Construct a new IdSet. The load function is used to obtain the initial list
     * of ids.
     *
     * @param loadFunction A function returning or promising an array of strings, the initial ids.
     */
    constructor(loadFunction: () => readonly string[] | Promise<readonly string[]>);
    /**
     * Add the given id to the set.
     *
     * @param id The id to add.
     * @returns A Promise that is resolved when done.
     */
    add(id: string): Promise<void>;
    /**
     * Remove the given id from the set.
     *
     * @param id The id to remove.
     * @returns A Promise that is resolved when done.
     */
    remove(id: string): Promise<void>;
    /**
     * Determine whether the given id is contained in this set.
     *
     * @param id The id to check.
     * @returns A Promise for whether the id is in this set.
     */
    includes(id: string): Promise<boolean>;
    /**
     * Iterate over all ids in this set. Iteration happens sequentially. If the
     * callback returns a Promise or thenable, it is awaited before continuing with
     * the next element.
     *
     * @param callbackFn The function to execute for each set element.
     * @returns A Promise that is resolved when iteration is finished.
     */
    each(callbackFn: (id: string) => any): Promise<void>;
}