toUtc method
Returns a Period with the start and end in UTC.
If this
isUtc, it will be returned.
If eiher start or end is not in UTC, a new Period will be created
with the start and end converted to UTC.
Implementation
Period toUtc() {
if (isUtc ?? false) return this;
return Period(
start: start.toUtc(),
end: end.toUtc(),
);
}