Reqwest hangs when manually polled in impl Future block

[gakonst]

For some reason the following code hangs. I sense that I might be doing something fundamentally wrong and that I should probably be storing the future inside the struct?

Repro:

use std::future::Future;
use std::task::{Context, Poll};
use std::pin::Pin;

#[derive(Clone, Debug)]
pub struct Thing;

impl Future for Thing {
    type Output = ();

    fn poll(self: Pin<&mut Self>, ctx: &mut Context) -> Poll<Self::Output> {
        let mut fut = Box::pin(reqwest::get("https://httpstat.us/200"));
        let _res = match fut.as_mut().poll(ctx) {
            Poll::Ready(ret) => ret,
            Poll::Pending => return Poll::Pending,
        };

        // do something with the result
        Poll::Ready(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[tokio::test]
    async fn test_thing() {
        let _logger = env_logger::init();
        let thing = Thing;
        // hangs here
        let ret = thing.await;
        dbg!(ret);
    }
}

Running it with RUST_LOG = hyper results in the following logs:

[2020-06-15T10:50:47Z TRACE hyper::client::pool] checkout waiting for idle connection: ("https", httpstat.us)
[2020-06-15T10:50:47Z TRACE hyper::client::connect::http] Http::connect; scheme=Some("https"), host=Some("httpstat.us"), port=None
[2020-06-15T10:50:47Z TRACE hyper::client::pool] checkout dropped for ("https", httpstat.us)
[2020-06-15T10:50:47Z DEBUG hyper::client::connect::dns] resolving host="httpstat.us"

[dependencies]
reqwest = "0.10.6"
env_logger = "0.7.1"

[dev-dependencies]
tokio = { version = "0.2.21", features = ["macros"] }

[seanmonstar]

If you drop the future after polling, it will cancel and never wake up the task again. You need to store it in your custom future. You might find it easier to just use an async fn.

[gakonst]

Yeah thought so, thank you for confirming.