export declare class RequestHandler {
    readonly _remember: boolean;
    _respond_from_cache: boolean;
    _cache: Record<string, Promise<string>>;
    constructor(remember: boolean);
    request(url: string): Promise<string>;
    clear_cache(): void;
    disable_responding_from_cache(): void;
    enable_responding_from_cache(): void;
}
export declare class FetchNetworkError extends Error {
    constructor(message?: string);
}