export declare class Observer<T> {
    private listeners;
    constructor();
    notify(value: any): void;
    error(error: any): void;
    subscribe(success?: (value: T) => void, error?: (error: any) => void): ObserverListener<T>;
    unsubscribe(listener: ObserverListener<T>): void;
}
export declare class ObserverListener<T> {
    success: (value: T) => void;
    error: (error: any) => void;
    private observer;
    constructor(success: (value: T) => void, error: (error: any) => void, observer: Observer<T>);
    unsubscribe(): void;
}