**Use case**

Workload generation with continuous queries.

**Describe the solution you'd like**

Similar to now() but non-constant.

registerFunctionToStartOfMillisecond(factory);
    registerFunctionToStartOfSecond(factory);
    registerFunctionToStartOfMinute(factory);
    registerFunctionToStartOfFiveMinutes(factory);
    registerFunctionToStartOfTenMinutes(factory);
    registerFunctionToStartOfFifteenMinutes(factory);
    registerFunctionToStartOfHour(factory);
    registerFunctionToStartOfInterval(factory);
    registerFunctionToStartOfISOYear(factory);
    registerFunctionToRelativeYearNum(factory);
    registerFunctionToRelativeQuarterNum(factory);
    registerFunctionToRelativeMonthNum(factory);
    registerFunctionToRelativeWeekNum(factory);
    registerFunctionToRelativeDayNum(factory);
    registerFunctionToRelativeHourNum(factory);
    registerFunctionToRelativeMinuteNum(factory);
    registerFunctionToRelativeSecondNum(factory);
    registerFunctionToTime(factory);
    registerFunctionNow(factory);
    registerFunctionNow64(factory);
    registerFunctionToday(factory);
    registerFunctionYesterday(factory);
    registerFunctionTimeSlot(factory);
    registerFunctionTimeSlots(factory);
    registerFunctionToYYYYMM(factory);
    registerFunctionToYYYYMMDD(factory);
    registerFunctionToYYYYMMDDhhmmss(factory);
    registerFunctionAddNanoseconds(factory);
    registerFunctionAddMicroseconds(factory);
    registerFunctionAddMilliseconds(factory);