Faster but not fastest

main.rs

use std::collections::HashMap;
use std::io::{self, prelude::*};

struct Counter {
    items: HashMap<String, usize>,
}

impl Counter {
    fn new() -> Counter {
        return Counter {
            items: HashMap::with_capacity(1000),
        };
    }
    fn add(&mut self, st: String) {
        let x = self.items.entry(st).or_insert(0);
        *x += 1;
    }

    fn render(&self) {
        for (key, val) in &self.items {
            println!("{}\t{}", val, key);
        }
    }
}

fn main() -> Result<(), io::Error> {
    let mut c = Counter::new();

    for line in io::stdin().lock().lines() {
        c.add(line?);
    }

    c.render();

    Ok(())
}