Rust has no built-in progress bar; you must add the indicatif crate to your Cargo.toml and use ProgressBar::new to create one. Add indicatif = "0.17" to your dependencies, then initialize and update the bar in your loop using pb.tick() or pb.set_position().
use indicatif::ProgressBar;
fn main() {
let pb = ProgressBar::new(100);
for i in 0..100 {
// do work
pb.inc(1);
}
pb.finish();
}