/**
 * Start promise after delaying.
 *
 * @param {number} millisecond
 * - a time for the delay
 *
 * @return {Promise<void>}
 * A void promise
 *
 * @example
 * promiseDelay(300)
 *   .then(doSomething)
 * // return a void promise after delay 300 ms
 */
export default function promiseDelay(millisecond: number): Promise<void>;