import { Metadata } from '@grpc/grpc-js';
/**
 * An extension of grpc.Metadata which provides a convenient way to
 * add an Authorization metadata header, and ensures every bearer token
 * going over the wire is prefixed with 'Bearer '
 */
declare class IlpCredentials extends Metadata {
    private static BEARER_PREFIX;
    /**
     * Static initializer, which constructs a new IlpCredentials object and adds
     * an Authorization entry.  If token is undefined, an Authorization header will
     * still be added, but the call will ultimately fail as Unauthorized
     *
     * @param token an optional access token to be added to IlpCredentials
     * @return a new instance of IlpCredentials, with an Authorization header
     */
    static build(token?: string): IlpCredentials;
}
export default IlpCredentials;