operator == method
Checks equality between two ZoneId instances.
Two zone IDs are equal if their string representations match.
Example:
ZoneId z1 = ZoneId.of('UTC');
ZoneId z2 = ZoneId.UTC;
print(z1 == z2); // true
Implementation
@override
bool operator ==(Object other) {
if (identical(this, other)) return true;
return other is ZoneId && _id == other._id;
}