/**
 * Copyright 2014 IBM Corp. All Rights Reserved.
 *
 * 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
 */
/// <reference types="node" />
import { Readable } from 'stream';
interface SynthesizeStream extends Readable {
    _readableState: any;
}
/**
 * pipe()-able Node.js Readable stream - accepts text in the constructor and emits binary audio data in its 'message' events
 *
 * Cannot be instantiated directly, instead created by calling #synthesizeUsingWebSocket()
 *
 * Uses WebSockets under the hood.
 * @param {Object} options
 * @constructor
 */
declare class SynthesizeStream extends Readable {
    static WEBSOCKET_CONNECTION_ERROR: string;
    private options;
    private socket;
    private initialized;
    private authenticated;
    /**
     * pipe()-able Node.js Readable stream - accepts text and emits binary audio data in its 'message' events
     *
     * Uses WebSockets under the hood.
     *
     *
     * Note that the WebSocket connection is not established until the first chunk of data is recieved. This allows for IAM token request management by the SDK.
     *
     * @param {Object} options
     * @param {String} options.text - The text that us to be synthesized. Provide plain text or text that is annotated with SSML. SSML input can include the SSML <mark> element. Pass a maximum of 5 KB of text.
     * @param {String} options.accept - The requested audio format (MIME type) of the audio.
     * @param {String[]} [options.timings] - An array that specifies whether the service is to return word timing information for all strings of the input text
     * @param {String} [options.voice='en-US_MichaelVoice'] - The voice that is to be used for the synthesis.
     * @param {String} [options.customization_id] - The customization ID (GUID) of a custom voice model that is to be used for the synthesis.
     * @param {String} [options.url='wss://stream.watsonplatform.net/speech-to-text/api'] base URL for service
     * @param {String} [options.watson-token] - Auth token
     * @param {String} [options.access_token] - IAM auth token
     * @param {Object} [options.headers] - Only works in Node.js, not in browsers. Allows for custom headers to be set, including an Authorization header (preventing the need for auth tokens)
     * @param {Boolean} [options.x-watson-learning-opt-out=false] - set to true to opt-out of allowing Watson to use this request to improve it's services
     * @param {String} [options.x-watson-metadata] - Associates a customer ID with data that is passed over the connection.
     * @param {IamTokenManagerV1} [options.token_manager] - Token manager for authenticating with IAM
     * @param {Boolean} [options.rejectUnauthorized] - If true, disable SSL verification for the WebSocket connection
     *
     * @constructor
     */
    constructor(options: any);
    initialize(): void;
    _read(): void;
    /**
     * This function retrieves an IAM access token and stores it in the
     * request header before calling the callback function, which will
     * execute the next iteration of `_read()`
     *
     *
     * @private
     * @param {Function} callback
     */
    setAuthorizationHeaderToken(callback: any): void;
}
export = SynthesizeStream;