當年在做go時，很羨慕它的時間有微秒，納秒，在做性能優化時，能很小顆粒度的查看引入方法執行的時間，當時.net的DateTime只有毫秒（雖然也有別的辦法獲取）。現在，在最新的.NET7 Preview4中，DateTime也有微秒和納秒了，倍感親切。

納秒在百位上，沒有十位和個位，但這也說明.NET在進化，向高性能進化，在乎微秒和百位納秒了（哈哈）。

下面是引入這兩個時間單位的實現：

namespace System {public struct DateTime {public DateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int microsecond);public DateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int microsecond, System.DateTimeKind kind);public DateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int microsecond, System.Globalization.Calendar calendar);public int Microsecond { get; }public int Nanosecond { get; }public DateTime AddMicroseconds(double value);}public struct DateTimeOffset {public DateTimeOffset(int year, int month, int day, int hour, int minute, int second, int millisecond, int microsecond, System.TimeSpan offset);public DateTimeOffset(int year, int month, int day, int hour, int minute, int second, int millisecond, int microsecond, System.TimeSpan offset, System.Globalization.Calendar calendar);public int Microsecond { get; }public int Nanosecond { get; }public DateTimeOffset AddMicroseconds(double microseconds);}public struct TimeSpan {public const long TicksPerMicrosecond = 10L;public const long NanosecondsPerTick = 100L;public TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds, int microseconds);public int Microseconds { get; }public int Nanoseconds { get; }public double TotalMicroseconds { get; }public double TotalNanoseconds { get; }public static TimeSpan FromMicroseconds(double microseconds);}public struct TimeOnly {public TimeOnly(int day, int hour, int minute, int second, int millisecond, int microsecond);public int Microsecond { get; }public int Nanosecond { get; }}
}