getUtcOffset
Determines the offset to UTC in effect at the time and in the time zone of @datetime.
The offset is the number of microseconds that you add to UTC time to arrive at local time for the time zone (ie: negative numbers for time zones west of GMT, positive numbers for east).
If @datetime represents UTC time, then the offset is always zero.
Return
the number of microseconds that should be added to UTC to get the local time
Since
2.26