Connecting twice to the same broker causes AsyncClient to get stuck

[Altair-Bueno]

MRE

use paho_mqtt::AsyncClient;
use paho_mqtt::ConnectOptionsBuilder;
use paho_mqtt::CreateOptions;
use paho_mqtt::Error;

#[tokio::main]
async fn main() -> Result<(), Error> {
    let client = AsyncClient::new(CreateOptions::default())?;

    println!("First one connecting");
    client
        .connect(
            ConnectOptionsBuilder::new()
                .server_uris(&["test.mosquitto.org:1883"])
                .finalize(),
        )
        .await?;
    println!("Fist one connected");

    println!("Second one connecting");
    client
        .connect(
            ConnectOptionsBuilder::new()
                .server_uris(&["test.mosquitto.org:1883"])
                .finalize(),
        )
        .await?;
    println!("Second one connected");

    Ok(())
}

First one connecting
Fist one connected
Second one connecting

repr-async-client-stuck-double-connect.zip

Current behavior

Connecting twice to the same broker causes AsyncClient to get stuck on the second connect call.

Expected behaviour

Second connect call should be ignored, as it is already connected.

Additional information

Setting different protocols doesn't change anything

[fpagliughi]

I was able to recreate this. Previously I had thought it was something in the C lib, but that doesn't appear to be the case. The call down to attempt the second connection never happens. So it must be something here getting hung up.