offsetFor method
Finds the zone offset that applies at the given instant
.
Implementation
NamedZoneOffset offsetFor(HasInstant instant) {
var i = transitions.toList().lowerBoundBy<HasInstant>(
ZoneTransition((b) => b
..transitionTime = instant.asInstant
..offset = NamedZoneOffset('', false, 0)),
(t) => t.transitionTime);
if (i == transitions.length) {
return rule.offsetFor(instant);
}
return transitions[max(0, i - 1)].offset;
}