Convert icalendar::CalendarDateTime::WithTimezone to chrono::DateTime

[WhyNotHugo]

I'd like to convert a icalendar::CalendarDateTime::WithTimezone to a chrono::DateTime.

I don't think that a chrono::offset::TimeZone can be created with the TZ data inside an icalendar event. This TZ data is often missing info too -- usually transitions relevant to the date encoded are included, but not other unrelated transitions or exceptions.

It might be simpler (or less error prone) to have just a helper method that converts the time to chrono::DateTime<UTC>.

[WhyNotHugo]

Another good approach is to parse VTIMEZONE into some special type first (e.g.: VTimeZone).

And then some helper function to convert:
(icalendar::CalendarDateTime::WithTimezone, VTimeZone) -> chrono::DateTime

[WhyNotHugo]

Ok, after re-reading the spec and looking closely at chrono's API, I think the best thing here is to implement a VTimeZone type, which implements chrono::offset::TimeZone. VTimeZone should also impl TryFrom<icalendar::parser::Component>.

Props of value-type UTC-OFFSET can themselves be mapped to chrono::offset::Offset.