message: Make ack tests safe against consumer state consistency
diff: @@ -601,6 +601,7 @@ mod jetstream {
  }
  client.flush().await.unwrap();
  + tokio::time::sleep(Duration::from_millis(100)).await;
  let info = consumer.info().await.unwrap();
  assert_eq!(info.num_ack_pending, 9);
  @@ -610,6 +611,7 @@ mod jetstream {
  }
  client.flush().await.unwrap();
  + tokio::time::sleep(Duration::from_millis(100)).await;
  let info = consumer.info().await.unwrap();
  assert_eq!(info.num_ack_pending, 8);
  @@ -623,6 +625,7 @@ mod jetstream {
  }
  client.flush().await.unwrap();
  + tokio::time::sleep(Duration::from_millis(100)).await;
  let info = consumer.info().await.unwrap();
  assert_eq!(info.num_ack_pending, 8);
  }
  