Tokio multiple periodic actions with Interval

cargo.toml

[package]
name = "multidelaytest"
version = "0.1.0"
authors = ["Jeff McBride"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
tokio = { version = "0.2", features = ["macros", "time", "sync", "rt-core", "rt-threaded", "rt-util", "stream"] }
futures = "0.3"

main.rs

use futures::future;
use std::time::Duration;
use std::thread;

async fn start(frequencies: Vec<f32>) {
    tokio::spawn(async move {
        let mut streams = Vec::new();
        for f in frequencies {
            streams.push(tokio::time::interval(Duration::from_secs_f32(1.0 / f)));
        }   
        loop {
            let futures = streams.iter_mut().map(|s| {Box::pin(s.tick())});
            let (_res, idx, _remaining_futures) = future::select_all(futures).await;
            println!("Got sensor {:?}", idx);
        }
    }).await.unwrap()
}

#[tokio::main]
async fn main() {
    println!("Launching background timers");
    start(vec![0.5, 1.0, 2.0]).await;
}