Let's look at how we can make that work.

## pytest.mark.anyio

If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously.

## HTTPX

Then at some point, it finally is your turn. You go to the counter, get your burgers and come back to the table.

<img src="/img/async/concurrent-burgers/concurrent-burgers-06.png" class="illustration">

You and your crush eat the burgers and have a nice time. ✨

<img src="/img/async/concurrent-burgers/concurrent-burgers-07.png" class="illustration">

!!! info

- Some apiserver metrics were changed, as follows.
  - `priority_level_seat_count_samples` is replaced with `priority_level_seat_utilization`, which samples every nanosecond rather than every millisecond; the old metric conveyed utilization despite its name.
  - `priority_level_seat_count_watermarks` is removed.

- This PR adds the following metrics for API Priority and Fairness.
  - **apiserver_flowcontrol_priority_level_seat_count_samples**: histograms of seats occupied by executing requests (both regular and final-delay phases included), broken down by priority_level; the observations are taken once per millisecond.

- Feat: change parittion style to GPT on Windows ([#101412](https://github.com/kubernetes/kubernetes/pull/101412), [@andyzhangx](https://github.com/andyzhangx)) [SIG Storage and Windows]

### Documentation

- Feat: azure file migration go beta in 1.21. Feature gates CSIMigration to Beta (on by default) and CSIMigrationAzureFile to Beta (off by default since it requires installation of the AzureFile CSI Driver)

### OpenStack

- The `openstack-heat` provider for `kube-up` is deprecated and will be removed
  in a future release. Refer to Issue [#49213](https://github.com/kubernetes/kubernetes/issues/49213)
  for background information.

### Scheduling

science

// scot : 2014-01-23 Dot Scot Registry Limited
scot

// search : 2016-06-09 Charleston Road Registry Inc.
search

// seat : 2014-05-22 SEAT, S.A. (Sociedad Unipersonal)
seat

// secure : 2015-08-27 Amazon Registry Services, Inc.
secure

// security : 2015-05-14 XYZ.COM LLC
security

// seek : 2014-12-04 Seek Limited
seek

    - `apiserver_flowcontrol_demand_seats_smoothed`: Smoothed seat demands
    - `apiserver_flowcontrol_target_seats`: Seat allocation targets
    - `apiserver_flowcontrol_seat_fair_frac`: Fair fraction of server's concurrency to allocate to each priority level that can use it

- Introduced new apiserver metric `apiserver_flowcontrol_current_inqueue_seats`. This metric is analogous to `apiserver_flowcontrol_current_inqueue_requests`, but tracks the total number of seats, as each request can take more than one seat. ([#119385](https://github.com/kubernetes/kubernetes/pull/119385), [@andrewsykim](https://github.com/andrewsykim))