test_cases.rs

use futures::future::FutureExt as _;
use futures::stream::StreamExt as _;
use futures::stream;
use futures::join;
use std::task::Poll;
use std::time::Duration;
use std::time::Instant;

async fn pending_futures() {
    let (tx, rx) = flume::bounded(4);
    let consumer_future = consumer(rx);

    let stream = stream::repeat(());
    let forward_future = stream.map(Ok).forward(tx.into_sink());

    
    let idle_pending_future = futures::future::poll_fn(|ctx| -> Poll<()> {
        Poll::Pending
    });

    let busy_pending_future = futures::future::poll_fn(|ctx| -> Poll<()> {
        ctx.waker().wake_by_ref();
        dbg!(Instant::now());
        Poll::Pending
    });
}

async fn async_std_blocking() {
    

    let futures = (0..12).map(|_| {
        async_std::task::spawn(async move {
            block();
        })
    });

    let fut = async_std::task::spawn(async move {
        loop {
            async_std::task::sleep(Duration::from_millis(100)).await;
            println!("i'm alive!");
        }
    });

    join!( futures::future::join_all( futures), fut);
}


async fn consumer(rx: flume::Receiver<()>) {
    rx.into_stream().for_each(|()| async move {
        println!("do nothing");
    }).await;
}


fn block() {
    loop {
        eprintln!();
    }
}