/**
 * @license
 * Copyright 2026 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
/**
 * Type definition for a function that selects an item based on the context.
 */
export type Router<T, C> = (items: Readonly<Record<string, T>>, context: C, errorContext?: {
    failedKeys: ReadonlySet<string>;
    lastError: unknown;
}) => Promise<string | undefined> | string | undefined;
/**
 * Runs a core operation with selection and failover support.
 * Internal helper to unify Promise and Generator logic.
 */
export declare function runWithRouting<T, C, TYield>(items: Readonly<Record<string, T>>, context: C, router: Router<T, C>, runFn: (item: T) => AsyncGenerator<TYield, void, void> | Promise<TYield>): AsyncGenerator<TYield, void, void>;