export interface BackoffOptions {
    initialDelay?: number;
    maxDelay?: number;
    timeout?: number;
    signal?: AbortSignal;
    onError?: (error: unknown, attempt: number) => void;
    now?: () => number;
}
/** Context-adapted stdlib exponential backoff. */
export declare function backoff<T>(work: (attempt: number) => Promise<T>, options?: BackoffOptions): Promise<T>;