/// tip

Prefer to use the `Annotated` version if possible.

///

```Python hl_lines="10"
{!> ../../docs_src/header_params/tutorial002.py!}
```

////

/// warning

Before setting `convert_underscores` to `False`, bear in mind that some HTTP proxies and servers disallow the usage of headers with underscores.

///

## Duplicate headers

    return emptyListIterator();
  }

  /**
   * Returns the empty iterator.
   *
   * <p>The {@link Iterable} equivalent of this method is {@link ImmutableSet#of()}.
   */
  // Casting to any type is safe since there are no actual elements.
  @SuppressWarnings("unchecked")
  static <T extends @Nullable Object> UnmodifiableListIterator<T> emptyListIterator() {
    return (UnmodifiableListIterator<T>) ArrayItr.EMPTY;

      //   A) it's not specified that "" is the path to the working directory.
      //   B) if we're getting this path for recursive delete, it's typically not possible to
      //      delete the working dir with a relative path anyway, so it's ok to fail.
      //   C) if we're getting it for opening a new SecureDirectoryStream, there's no need to get

      //   A) it's not specified that "" is the path to the working directory.
      //   B) if we're getting this path for recursive delete, it's typically not possible to
      //      delete the working dir with a relative path anyway, so it's ok to fail.
      //   C) if we're getting it for opening a new SecureDirectoryStream, there's no need to get

contributors to follow so that we can have a chance of keeping on top of
things.

Some of the ideas are documented in the [Maven Wiki][maven-wiki]
which might be interesting to read and for further discussion.

Getting Started
---------------

+ Make sure you have a [JIRA account](https://issues.apache.org/jira/).
+ Make sure you have a [GitHub account](https://github.com/signup/free).

  //
  // WARNING: The destructor of this class is marked as protected to disallow
  // clients from directly destroying this object since it may manage it's own
  // lifetime through ref counting. Thus this must be allocated on the heap and
  // clients MUST call Release() in order to destroy an instance of this class.
  virtual void Release() = 0;

		}
		if err == nil {
			if etag != test.ETag {
				t.Fatalf("Test %d: ETag mismatch: got %s - want %s", i, etag, test.ETag)
			}
		}
	}
}

// Tests for issue reproduced when getting the right encrypted
// offset of the object.
func TestGetDecryptedRange_Issue50(t *testing.T) {
	rs, err := parseRequestRangeSpec("bytes=594870256-594870263")
	if err != nil {
		t.Fatal(err)
	}

    response = client.post(
        "/admin/?token=jessica", headers={"X-Token": "fake-super-secret-token"}
    )
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "Admin getting schwifty"}


@needs_py39
def test_admin_invalid_header(client: TestClient):
    response = client.post("/admin/", headers={"X-Token": "invalid"})
    assert response.status_code == 400, response.text

- Kubernetes 1.23 is now built with go1.19.4. To match behavior of previous Kubernetes 1.23 patch releases:
  - `kube-apiserver` defaults the GOGC setting to 63, to approximate go1.17 garbage collection memory performance in heavily loaded API servers

## Alternative (old): `Query` as the default value

Previous versions of FastAPI (before <abbr title="before 2023-03">0.95.0</abbr>) required you to use `Query` as the default value of your parameter, instead of putting it in `Annotated`, there's a high chance that you will see code using it around, so I'll explain it to you.

/// tip