futures-rs is a library that implements zero-cost futures and streams in Rust.
The core concepts of the futures crate are Future and Stream.
There are some general Future trait implementations in the futures crate. One of them is implemented in futures::sync::oneshot module and is available through futures::oneshot function:
extern crate futures;
use std::thread;
use futures::Future;
fn expensive_computation() -> u32 {
// ...
200
}
fn main() {
// The oneshot function returns a tuple of a Sender and a Receiver.
let (tx, rx) = futures::oneshot();
thread::spawn(move || {
// The complete method resolves a values.
tx.complete(expensive_computation());
});
// The map method applies a function to a value, when it is resolved.
let rx = rx.map(|x| {
println!("{}", x);
});
// The wait method blocks current thread until the value is resolved.
rx.wait().unwrap();
}