Draft / Experimental: Zith documentation describes a language under active development. Check Implementation Status before relying on a feature.
There is no async or thread model in HIR today, and concurrency is not planned as a function kind. The direction is stdlib and runtime APIs instead.
async fn is legacy reserved syntax: the parser accepts the declaration and skips its body entirely, with no async lowering and no HIR contract behind it. yield, spawn, and await are reserved tokens, not core operators or statements. Treat all four as historical parser affordances rather than a preview of the concurrency design.
Use the Concurrency reference to understand the intended model and Implementation Status to track delivery.