import { MonoTypeOperatorFunction } from 'rxjs';
/**
 * RxJS operator to apply to a stream that you want to poll every "period" milliseconds after an optional "initialDelay" milliseconds.
 *
 * @param period - Indicates the delay between 2 polls.
 * @param initialDelay - Indicates the delay before the first poll occurs.
 * @example This example shows how to do an HTTP GET every 5 seconds:
 * ```ts
 * http.get('http://api').pipe(poll(5000)).subscribe(result => {});
 * ```
 * @public
 */
export declare function poll<T>(period: number, initialDelay?: number): MonoTypeOperatorFunction<T>;