clearTimeout (timeout) {
    // If the timeout is a FastTimer, call its own clear method.
    if (timeout[kFastTimer]) {
      /**
       * @type {FastTimer}
       */
      timeout.clear()
      // Otherwise it is an instance of a native NodeJS.Timeout, so call the
      // Node.js native clearTimeout function.
    } else {
      clearTimeout(timeout)
    }
  }
The clearTimeout method cancels an instantiated Timer previously created
by calling setTimeout.

@param {NodeJS.Timeout|FastTimer} timeout