static getTiming(task, taskTimingsByEvent) {
    /** @type {Timing} */
    let timing = task;
    if (taskTimingsByEvent) {
      timing = taskTimingsByEvent.get(task.event) || DEFAULT_TIMING;
    }

    const {duration, startTime} = timing;
    return {duration, startTime};
  }
Get timing from task, overridden by taskTimingsByEvent if provided.
@param {LH.Artifacts.TaskNode} task
@param {Map<Lantern.Types.TraceEvent, LH.Gatherer.Simulation.NodeTiming>|undefined} taskTimingsByEvent
@return {Timing}