import { IHeadersProvider } from '..';
import { TokenGrantAudienceType } from './IHeadersProvider';
/**
 * The `NullAuthProvider` class is a no-op implementation of {@link IHeadersProvider}.
 * It returns an empty string for the authorization header.
 *
 * This is used when no authentication is required.
 */
export declare class NullAuthProvider implements IHeadersProvider {
    getHeaders(audience: TokenGrantAudienceType): Promise<{
        authorization: string;
    }>;
}