Function timer

timer(callback, delay?, time?): Timer
Schedules and returns a new timer, invoking the specified callback repeatedly until the timer is stopped. The callback is passed the (apparent) elapsed time since the timer became active.
Parameters
- callback: ((elapsed) => void)
  A callback function to be invoked and passed in the apparent elapsed time since the timer became active in milliseconds.
  - - (elapsed): void
    - Parameters
      elapsed: number
      Returns void
- Optional delay: number
  An optional numeric delay in milliseconds (default = 0) relative to time.
- Optional time: number
  An optional time in milliseconds relative to which the delay is calculated (default = now).
Returns Timer