Implement `GetTimeZoneTransition` method for `ZonedDateTime`

[nekevss]

Related to ongoing work for #13.

The method GetTimeZoneTransition needs to be implemented for ZonedDateTime.

This may involve extending the TzProvider trait and implementing that extension on FsTzdbProvider.

Initial thought on how the implementation may look would be to add the method like below:

trait TimeZoneProvider {
  // ...
  // Existing trait methods
  
  fn get_timezone_transition(&self, epoch_nanoseconds: i128, direction: TransitionDirection) -> EpochNanoseconds;
}

[JohannesHelleve]

Hi,

is this one completed?

Found the method in the code I think? Link

[nekevss]

is this one completed?

This one is not complete as of current, but it does require some work with the time zone provider in tzdb.rs

[JohannesHelleve]

May I ask what the code i sent the link to is?

Is the issue more about cleaning up the method and altering the trait?

[nekevss]

The linked code is to the method implementation, but notably the functional portion of the code from the provider get_named_tz_transition is not yet implemented (See this section for more).

You can definitely take a stab at this issue if you'd like. But the providers themselves may have little bit of an overhaul in the future with the recent datagen changes and the open zoneinfo PR, so it may be a bit complex.

[HenrikTennebekk]

@nekevss can you assign this issue to me?

[HenrikTennebekk]

@nekevss I had some issues with this issue, you may unassign me as I've started working on other stuff

[nekevss]

Related issue about what Temporal considers a transition.

tc39/proposal-temporal#3105