icu_calendar 
The icu_calendar crate contains the core types used by ICU4X for dealing
with dates, times, and custom calendars.
The [types] module has a lot of common types for dealing with dates and times.
[Calendar] is a trait that allows one to define custom calendars, and [Date]
can represent dates for arbitrary calendars.
The [iso] and [gregorian] modules contain implementations for the ISO and
Gregorian calendars respectively.
More Information
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