atomics

use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;
use std::thread;

fn main() {
    let counter = Arc::new(AtomicUsize::new(0));

use std::collections::HashMap;
use std::sync::{Arc, Mutex, PoisonError};

#[derive(Default)]
struct Metrics {
    per_endpoint: HashMap<String, u64>,