/**
 * @license
 * Copyright 2017 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 { RepoInfo } from '../core/RepoInfo';
export interface TransportConstructor {
    new (connId: string, repoInfo: RepoInfo, applicationId?: string, appCheckToken?: string, authToken?: string, transportSessionId?: string, lastSessionId?: string): Transport;
    isAvailable: () => boolean;
    responsesRequiredToBeHealthy?: number;
    healthyTimeout?: number;
}
export declare abstract class Transport {
    /**
     * Bytes received since connection started.
     */
    abstract bytesReceived: number;
    /**
     * Bytes sent since connection started.
     */
    abstract bytesSent: number;
    /**
     * An identifier for this connection, used for logging
     */
    abstract connId: string;
    /**
     * @param connId - An identifier for this connection, used for logging
     * @param repoInfo - The info for the endpoint to send data to.
     * @param transportSessionId - Optional transportSessionId if this is connecting to an existing transport session
     * @param lastSessionId - Optional lastSessionId if there was a previous connection
     * @interface
     */
    constructor(connId: string, repoInfo: RepoInfo, transportSessionId?: string, lastSessionId?: string);
    /**
     * @param onMessage - Callback when messages arrive
     * @param onDisconnect - Callback with connection lost.
     */
    abstract open(onMessage: (a: {}) => void, onDisconnect: (a?: boolean) => void): void;
    abstract start(): void;
    abstract close(): void;
    /**
     * @param data - The JSON data to transmit
     */
    abstract send(data: {}): void;
    abstract markConnectionHealthy(): void;
    abstract markConnectionHealthy(): void;
}