import { GaxiosOptions } from 'gaxios';
import { AuthClient } from './authclient';
import { GetAccessTokenResponse, Headers } from './oauth2client';
/**
 * An AuthClient without any Authentication information. Useful for:
 * - Anonymous access
 * - Local Emulators
 * - Testing Environments
 *
 */
export declare class PassThroughClient extends AuthClient {
    /**
     * Creates a request without any authentication headers or checks.
     *
     * @remarks
     *
     * In testing environments it may be useful to change the provided
     * {@link AuthClient.transporter} for any desired request overrides/handling.
     *
     * @param opts
     * @returns The response of the request.
     */
    request<T>(opts: GaxiosOptions): Promise<import("gaxios").GaxiosResponse<T>>;
    /**
     * A required method of the base class.
     * Always will return an empty object.
     *
     * @returns {}
     */
    getAccessToken(): Promise<GetAccessTokenResponse>;
    /**
     * A required method of the base class.
     * Always will return an empty object.
     *
     * @returns {}
     */
    getRequestHeaders(): Promise<Headers>;
}