How to stop and drop an interval stream?

[reza-ebrahimi]

I have an interval stream that will be called when a request coming, The problem is after dropping websocket connection request, the interval doesn't stop and still continue to stream values.

// async-graphql subscription
#[Subscription]
impl SystemSubscription {
  // stat graphql subscription
  async fn stat(&self, _ctx: &Context<'_>) -> impl Stream<Item = i32> {
    // this interval stream should stop after dropping returned stream
    async_std::stream::interval(std::time::Duration::from_millis(1000)).map(|_| { 0 })
  }
}