/**
 * Copyright 2019, OpenCensus Authors
 *
 * 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.
 */
/** Returns the origin of the browser performance clock in epoch millis. */
export declare function getPerfTimeOrigin(): number;
/** Converts a browser performance timestamp into a Date. */
export declare function getDateForPerfTime(perfTime: DOMHighResTimeStamp): Date;
/**
 * Converts a time in browser performance clock milliseconds into a nanosecond
 * precision ISO date string.
 */
export declare function getIsoDateStrForPerfTime(perfTime: number): string;