import { RefreshOptions } from './oauth2client';
import { BaseExternalAccountClient } from './baseexternalclient';
import { IdentityPoolClientOptions } from './identitypoolclient';
import { AwsClientOptions } from './awsclient';
export declare type ExternalAccountClientOptions = IdentityPoolClientOptions | AwsClientOptions;
/**
 * Dummy class with no constructor. Developers are expected to use fromJSON.
 */
export declare class ExternalAccountClient {
    constructor();
    /**
     * This static method will instantiate the
     * corresponding type of external account credential depending on the
     * underlying credential source.
     * @param options The external account options object typically loaded
     *   from the external account JSON credential file.
     * @param additionalOptions Optional additional behavior customization
     *   options. These currently customize expiration threshold time and
     *   whether to retry on 401/403 API request errors.
     * @return A BaseExternalAccountClient instance or null if the options
     *   provided do not correspond to an external account credential.
     */
    static fromJSON(options: ExternalAccountClientOptions, additionalOptions?: RefreshOptions): BaseExternalAccountClient | null;
}