How do i tell when the SSE stream is closed by the user?

[NotHolst]

When they connect to my SSE stream i'm adding them to a hashmap, upon disconnection i would like to remove them, but i don't really have the connection.

I'm using a BearerAuth security scheme to tell which user is connecting.

#[oai(path = "/resources.stream", method = "get", tag = ApiTags::ResourceEvents)]
    async fn index(
        &self,
        user: BearerAuth,
        client: Data<&Arc<redis::Client>>,
        app_state: Data<&Arc<AppState>>,
    ) -> EventStream<BoxStream<'static, ResourceEvent>> {
        let sender: broadcast::Sender<ResourceEvent> = broadcast::Sender::new(100);
        let user_rooms = vec![user.payload().sub];

        let mut store = app_state.resource_event_rooms.lock().await;
        for room in user_rooms {
            store.entry(room).or_insert(vec![]).push(sender.clone());
        }

        // I would like to remove the user from the above map when they disconnect.

        EventStream::new(
            async_stream::stream! {
                for i in 0.. {
                    tokio::time::sleep(Duration::from_secs(1)).await;
                    yield Event { value: i };
                }
            }
            .boxed(),
        )
    }