/**
 * @license
 * Copyright 2022 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { AuthInternal } from '../../model/auth';
import { Unsubscribe, User } from '../../model/public_types';
export declare class AuthMiddlewareQueue {
    private readonly auth;
    private readonly queue;
    constructor(auth: AuthInternal);
    pushCallback(callback: (user: User | null) => void | Promise<void>, onAbort?: () => void): Unsubscribe;
    runMiddleware(nextUser: User | null): Promise<void>;
}