OneshotSender is not Sync

[JakkuSakura]

I have a scenario like this

let table = Arc::new(DashMap::new());
let (tx, rx) = kannal::oneshot_async();
table.insert(1, tx);
tokio::spawn(async move {
    tabl.remove(1).unwrap().send(()).await;
});
rx.await

But I got
error[E0277]: *mut kanal::oneshot::OneshotInternal<()> cannot be shared between threads safely

[silvanshade]

This is a common issue with oneshot channels in various crates, even though technically some of the time it should be fine for them to impl Sync (since oneshot operations are usually by-value, meaning that self by-reference methods are unusable).

You can usually work around it by just wrapping the oneshot in a Mutex and then unwrapping with Mutex::into_inner at the send invocation site.