Other commenters have already provided examples for other languages, and it's the same for Rust: async functions are just regular functions that return an impl Future type. As a sync function, you can call a bunch of async functions and return the futures to your caller to handle, or you can block your current thread with the block_on function typically available through a handle (similar to the Io object here) provided by your favorite async runtime [0].
In other words, you don't need such an Io object upfront: You need it when you want to actually drive its execution and get the result. From this perspective, the Zig approach is actually less flexible than Rust.
In other words, you don't need such an Io object upfront: You need it when you want to actually drive its execution and get the result. From this perspective, the Zig approach is actually less flexible than Rust.
[0]: https://docs.rs/tokio/latest/tokio/runtime/struct.Handle.htm...