public static string ToSqlTimestamp(this DateTime d, int milliSecondsPrecision = 0) => d.ToString(DateTimeConstants.SqlTimestampFormat(milliSecondsPrecision));
public static string ToYYYYMMDD_HHMMSS_FFFFFF(this DateTime d, string separator = "-", int milliSecondsPrecision = 6) => d.ToYYYYMMDD_HHMMSS(separator) + d.ToString(DateTimeConstants.MilliSecondsFormat(milliSecondsPrecision, separator));