Robert Bastian

I don't really see the need for these, and I'm also not a fan of the `auto`, and especially `auto_iter` names. Meh

Context: I'm trying to replace https://github.com/robertbastian/icu4x/blob/ec32ad4a79707b1ddb7852ed1653ac2d86c27f3f/provider/datagen/src/baked_exporter.rs#L25 by a version that doesn't use the network (the current test does). However I cannot figure out an invocation for baked that doesn't use...

This invocation works with `HelloWorldProvider`: https://github.com/unicode-org/icu4x/blob/51bd08ec933a818245a76114da11b2173aeaab8b/provider/blob/src/export/mod.rs#L23-L27 It uses implicit exporter-derived defaults - what's the equivalent invocation for a baked provider?

I guess it's `.with_all_locales().with_fallback_mode(FallbackMode::Hybrid)`, which doesn't exist on the new API?

So what's the difference between `with_locales_and_fallback` with `::None` and `::External`, and `with_locales_no_fallback`?

I think I'm fine flattening it.

For the datetime use case, I think it would be useful to have a `FixedDecimal` constructor that accepts `usize, usize` as the integer and fractional parts. Then we avoid this...

I think it does. It would use `IntIterator::from(integer).chain(IntIterator::from(fractional))` and then shift the resulting `FixedDecimal` by `fractional.log10()`.

We have `std` features on all crates, so it can be conditional on that. I'm not sure this method should be tz-only though. Maybe we should have `get_system_locale`, that encapsulates...

`core::mem::size_of::()` is 32 on stable and 24 on nightly. That's nice, but maybe we can get it down to 16 if we make the owned type `Box` instead of `String`...