import { Emitter } from './emitter.js';
export declare type Subscriber<T> = (emit: Emitter<T>) => Unsubscriber;
export declare type Unsubscriber = {
    unsubscribe(): void;
} | (() => any) | void;
export interface ISubscription {
    unsubscribe(): void;
    readonly closed: boolean;
}
export interface IObserver<T> {
    start?(sub: ISubscription): any;
    next?(val: T): any;
    error?(err: Error): any;
    complete?(val?: any): any;
}
export interface IObservable<T> {
    subscribe(observer: IObserver<T>): ISubscription;
    subscribe(next: (val: T) => any, error?: (err: Error) => void, complete?: (val: any) => void): ISubscription;
}
export declare type IntoObservable<T> = IObservable<T> | Promise<T> | AsyncIterable<T> | Iterable<T>;