/**
 * Read all the values from the (a)synchronous iterator, apply the `f` function to each of them, and store the results into an array.
 * @template {T} type of the values returned by the source iterator.
 * @template {U} type of the values returned by the this iterator. The `f` function must return values of the same type.
 * @param {Iterable<T> | AsyncIterable<T>} it the (a)synchronous iterator to read the source values from.
 * @param {(t: T) => Promise<U>} f a function that will be applied to each value received from the iterator.
 * If it fails for any value, the returning promise will be rejected with the corresponding error.
 * @param {number} concurrency the maximum number of jobs running at a time.
 * A job is the concatenation of requesting a value to the source iterator plus calling the function `f` with that value.
 * @returns {Promise<Array<U>>} An array with the values resulting from applying the function `f` to each value of the iterator.
 * The values in the array will be in the same order as the iterator returned them.
 */
export declare function all<T, U>(it: Iterable<T> | AsyncIterable<T>, f: (t: T) => Promise<U | Iterable<U>>, concurrency?: number): Promise<Array<U>>;
/**
 * Returns a new asynchronous iterable that has `it` as source and applies the function `f` to each value of `it`, as being requested.
 * @template {T} type of the values returned by the source iterator.
 * @template {U} type of the values returned by the this iterator. The `f` function must return values of the same type.
 * @param {Iterable<T> | AsyncIterable<T>} it the source iterator that provides values.
 * @param {(t: T) => Promise<U>} f a function that will be applied to each value of the source iterator.
 * @param {number} concurrency the maximum number of jobs running at a time.
 * A job is the concatenation of requesting a value to the source iterator plus calling the function `f` with that value.
 * @param {boolean} backPressure if `concurrency` number of results are waiting to be consumed by the user,
 * no more values will be requested from the source iterator.
 * @returns {AsyncIterable<U>}
 */
export declare function execute<T, U>(it: Iterable<T> | AsyncIterable<T>, f: (t: T) => Promise<U | Iterable<U>>, concurrency?: number, backPressure?: boolean): AsyncIterable<U>;