return nil
}

// fakeNs is a mock struct for testing
type fakeNs struct {
	closed *atomic.Bool
	fd     uintptr
	inode  uint64
}

func newFakeNs(fd uintptr) *fakeNs {
	// the fake inode is the fd! magic.
	return &fakeNs{closed: &atomic.Bool{}, fd: fd, inode: uint64(fd)}
}

func newFakeNsInode(fd uintptr, inode uint64) *fakeNs {
	return &fakeNs{closed: &atomic.Bool{}, fd: fd, inode: inode}
}

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"

	"istio.io/istio/pkg/test/util/assert"
)

func TestWithProcFs(t *testing.T) {
	n := NewPodNetnsProcFinder(fakeFs())
	pod := &corev1.Pod{ObjectMeta: metav1.ObjectMeta{
		Name:      "foo",
		Namespace: "bar",
		UID:       types.UID("863b91d4-4b68-4efa-917f-4b560e3e86aa"),
	}}

		},
		Spec: corev1.PodSpec{ServiceAccountName: "sa"},
	}

	// this is usually called after add. so manually add the pod uid for now
	fakens := newFakeNs(123)
	closed := fakens.closed
	workload := WorkloadInfo{
		Workload: podToWorkload(pod),
		Netns:    fakens,
	}
	fixture.podNsMap.UpsertPodCacheWithNetns(string(pod.UID), workload)
	err := netServer.RemovePodFromMesh(ctx, pod)
	assert.NoError(t, err)

            activeThreads--
            startNextTask()
          }
        }
      }
    }
  }

  /**
   * This blocking queue hooks into a fake clock rather than using regular JVM timing for functions
   * like [poll]. It is only usable within task faker tasks.
   */
  private inner class TaskFakerBlockingQueue<T>(
    val delegate: BlockingQueue<T>,
  ) : AbstractQueue<T>(), BlockingQueue<T> {

Next, it 🤖 takes the first task to finish (let's say, our "slow-file" 📝) and continues whatever it had to do with it.

This parameter must be something like a function.

You **don't call it** directly (don't add the parenthesis at the end), you just pass it as a parameter to `Depends()`.

And that function takes parameters in the same way that *path operation functions* do.

!!! tip
    You'll see what other "things", apart from functions, can be used as dependencies in the next chapter.

Ztunnel was not designed to be a feature-rich data plane.
Quite the opposite - an *aggressively* small feature set is the key feature that makes ztunnel viable.
It very intentionally does not offer L7 (HTTP) functionality, for instance, which would likely violate some of the goals above, without contributing to them.

In our code example above, we don't use it directly, but we pass it to FastAPI for it to use it.

The `lifespan` parameter of the `FastAPI` app takes an **async context manager**, so we can pass our new `lifespan` async context manager to it.

```Python hl_lines="22"
{!../../../docs_src/events/tutorial003.py!}
```

## Alternative Events (deprecated)

!!! warning

You can import it directly from `fastapi`:

```python
from fastapi import Request
```

!!! tip
    When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.

    response = client.get(
        "/items/", headers={"X-Token": "fake-super-secret-token", "X-Key": "invalid"}
    )
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "X-Key header invalid"}


def test_get_invalid_second_header_users():
    response = client.get(
        "/users/", headers={"X-Token": "fake-super-secret-token", "X-Key": "invalid"}
    )