public final class CalendarInterval
The class representing calendar intervals. The calendar interval is stored internally in
an integer value representing the number of `months` in this interval,
an integer value representing the number of `days` in this interval,
a long value representing the number of `microseconds` in this interval.
The `months` and `days` are not units of time with a constant length (unlike hours, seconds), so
they are two separated fields from microseconds. One month may be equal to 28, 29, 30 or 31 days
and one day may be equal to 23, 24 or 25 hours (daylight saving).