import { IObserver } from './types.js';
import { Subscription } from './subscription.js';
export declare class Emitter<T> {
    private _observer;
    private _closed;
    _subscription?: Subscription;
    constructor(observer: IObserver<T>);
    next(val: T): any;
    error(err: Error): any;
    complete(val?: any): any;
    readonly closed: boolean;
}