Time - Time-interval Measurements

public class TimeHelper
{
    private long _start, _stop, _elapsed;

    /// <summary>
    /// 獲取初始時間戳
    /// </summary>
    public void start()
    {
        _start = Stopwatch.GetTimestamp();
    }

    /// <summary>
    /// 獲取終結時間戳
    /// </summary>
    public void stop()
    {
        _stop = Stopwatch.GetTimestamp();
    }

    /// <summary>
    /// 獲取高精度時間間隔
    /// </summary>
    /// <returns></returns>
    public double getTimeInteval()
    {
        return (_stop - _start) * (1.0 / Stopwatch.Frequency);
    }
}