import { Observable, ObservableInput, SchedulerLike } from 'rxjs'; export declare function expand(this: Observable, project: (value: T, index: number) => ObservableInput, concurrent?: number, scheduler?: SchedulerLike): Observable; export declare function expand(this: Observable, project: (value: T, index: number) => ObservableInput, concurrent?: number, scheduler?: SchedulerLike): Observable;