/*!
 * async
 * https://github.com/caolan/async
 *
 * Copyright 2010-2014 Caolan McMahon
 * Released under the MIT license
 */
export declare function onlyOnce<T>(callback: Callback): Callback;
export interface Callback {
    (err?: Error): void;
}
export interface ResultCallback<T> {
    (err?: Error, result?: T): void;
}
export interface IteratorCallback<T> {
    (item: T, callback: Callback): any;
}