Time functions are a prefect example of somewhere there should be expanded support for in the STD. I'm also of the opinion that there should be a generic and reasonable async runtime in STD, since having `async` in the language, but to direct way to use it without a crate or writing your own executor is awkward.
Then there are things like serialization and logging, which I like the idea of having promoted crates which are essentially just better advertised for newcomers. (Maybe included in the distribution already in some way).
But what if we did that 5 years ago? Oops. And even Java's API has problems too. Why not let it be provide by the ecosystem where it can qctually evolve?
It lacks a hybrid duration type. Instead, it splits durations into calendar and time durations and conflates the length of a `day` depending on whether it's in `Period` or `Duration`. And AFAIK, it doesn't support time zone aware duration rounding. And I don't see a way to compute a `Period` from two `ZonedDateTime` values in a way that respects time zone transitions.
To be clear, it's good. But there are mistakes that the Temporal project learned from and fixed.
(Temporal's single `Duration` type does have pros and cons, so I don't mean to frame having two distinct types as a strict negative. But it's very clunky.)
It's just it's not frequent.
There is very few things that need to be in the standard library. I only ever miss chrono or equivalent not being in std.