import { IObserver, IObservable } from "./Observable";
export declare type Subscriber<T> = (observer: IObservable<T>) => ISubscription | void;
export interface ISubscription {
    unsubscribe(): void;
}
export declare class EmptySubscription<T> implements IObservable<T>, ISubscription {
    closed(): boolean;
    complete(): void;
    error(): void;
    next(x: T): void;
    unsubscribe(): void;
}
export default class Subscription<T> implements IObservable<T>, ISubscription {
    protected observer?: IObserver<T>;
    protected source?: IObserver<T>;
    private sub?;
    constructor(observer?: IObserver<T>, subscriber?: Subscriber<T>);
    closed(): boolean;
    unsubscribe(): void;
    next(value: T): any;
    error(err: Error): Error;
    complete(): void;
}