/**
 * Usage:
 *
 * ```javascript
 *
 *   let t1 = time()
 *   execute some task....
 *   const t2 = time(t1)
 *   console.log(`the task took ${t2}` milliseconds`)
 *
 *     ```
 * @param input?
 */
export declare const time: (input?: void | [number, number]) => number | [number, number];
/**
 * returns a timestamp like `Date.now()` but in this case this timestamp means nothing special. Just extracting
 * two now() calls will give the millisecond difference: for example:
 *
 *
 * ```javascript
 *
 *   let t0 = now()
 *   execute some task...
 *   console.log(`the task took ${now()-t0}` milliseconds`)
 *
 *     ```
 */
export declare const now: () => number;