import { DelayFn } from '../types';
/**
 * Wait for an exponential increasing amount of time before retrying
 * @param initialDelay The initial amount of time in milliseconds to wait
 * @param factor The factor to increase the delay by
 * @param fastFirst Whether to immediately retry for the first attempt
 */
export declare function exponentialDelay(initialDelay: number, factor?: number, fastFirst?: boolean): DelayFn;