/**
 * Run an async function over all items in the array, with a specific concurrency limit.
 *
 * @param items - The array of items to process.
 * @param concurrency - The maximum number of concurrent executions.
 * @param fn - Async function to run for each item. Receives the item and its index.
 * @returns A Promise resolving to an array of PromiseSettledResult objects, preserving input order.
 *
 * Each result is a { status, value } or { status, reason } object, as from Promise.allSettled().
 * The pool will never run more than `concurrency` functions at once.
 */
export declare function runWithConcurrency<T, R>(items: T[], concurrency: number, fn: (item: T, index: number) => Promise<R>): Promise<PromiseSettledResult<R>[]>;