main.rs

use rayon::prelude::*;
use std::sync::Mutex;
use std::time::{Duration, Instant};

#[derive(Clone, Debug)]
pub struct IntervalTimer {
    pub period: Duration,
    pub delta: Instant,
}

impl IntervalTimer {
    pub fn new(period: Duration) -> Self {
        let delta = Instant::now();
        Self { period, delta }
    }

    /// Returns true if the interval between calls has exceeded the period
    pub fn ready(&mut self) -> bool {
        if self.delta.elapsed() < self.period {
            false
        } else {
            self.delta = self.delta + self.period;
            true
        }
    }
}

fn main() {
    let v: Vec<_> = std::iter::repeat(vec![1, 2, 3])
        .flatten()
        .take(30)
        .collect();
    let timer = Mutex::new(IntervalTimer::new(Duration::from_millis(20)));
    v.into_par_iter().for_each(|x| {
        for _ in 0..x {
            while !timer.lock().unwrap().ready() {}
        }
    });
}