thread_pool_backpressure.rs

// Source: https://gist.github.com/dns2utf8/98e3b9977c23c656788be36cca1f9477

use threadpool::Builder; // 1.7.1

fn main() {
    let max_jobs = 3;
    let pool = Builder::new().num_threads(1).build();
    
    let maybe_submit = |func| {
        if pool.queued_count() < max_jobs {
            pool.execute(func);
            Ok("submitted")
        } else {
            Err("full")
        }
    };
    
    
    let r = (0..10).map(|_| maybe_submit(|| ())).collect::<Vec<_>>();
    
    println!("submit result: {:#?}!", r);
}

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