import type { SchedulerLike } from 'rxjs';
import { Observable } from 'rxjs';
/**
 * An interval that emits with random delays
 * @kind Creator
 * @since 1.0.0
 * @param lower Minimum delay
 * @param upper Maximum delay
 * @param scheduler Scheduler to use
 * @return An observable that emits the iteration index, starting at 0
 * @example
 * import {intervalRandom} from '@aloreljs/rxutils';
 * import {asapScheduler} from 'rxjs';
 *
 * intervalRandom(1000, 2000).subscribe(); // emit every 1-2 seconds on the default scheduler
 * intervalRandom(1000, 2000, asapScheduler).subscribe(); // emit every 1-2 seconds on the ASAP scheduler
 */
export declare function intervalRandom(lower: number, upper: number, scheduler?: SchedulerLike): Observable<number>;