import type { NumberOfSeconds, PositiveInteger } from '@naturalcycles/js-lib/types';
import type { TransformOptions, TransformTyped } from '../stream.model.js';
export interface TransformThrottleOptions extends TransformOptions {
    /**
     * How many items to allow per `interval` of seconds.
     */
    throughput: PositiveInteger;
    /**
     * How long is the interval (in seconds) where number of items should not exceed `throughput`.
     */
    interval: NumberOfSeconds;
}
/**
 * Allows to throttle the throughput of the stream.
 * For example, when you have an API with rate limit of 5000 requests per minute,
 * `transformThrottle` can help you utilize it most efficiently.
 * You can define it as:
 *
 * _pipeline([
 *   // ...
 *   transformThrottle({
 *     throughput: 5000,
 *     interval: 60,
 *   }),
 *   // ...
 * ])
 *
 * @experimental
 */
export declare function transformThrottle<T>(opt: TransformThrottleOptions): TransformTyped<T, T>;