import (
	"context"
	"net"
	"syscall"
	"time"
)

// CheckPortAvailability - check if given host and port is already in use.
// Note: The check method tries to listen on given port and closes it.
// It is possible to have a disconnected client in this tiny window of time.
func CheckPortAvailability(host, port string, opts TCPOptions) (err error) {
	lc := &net.ListenConfig{
		Control: func(network, address string, c syscall.RawConn) error {

En utilisant seulement `BackgroundTasks` (et non `BackgroundTask`), il est possible de l'utiliser en tant que paramètre de *fonction de chemin* et de laisser **FastAPI** gérer le reste pour vous, comme en utilisant l'objet `Request` directement.

    assert e.value.code == status.WS_1008_POLICY_VIOLATION
    # and no error is leaked
    assert caught == []


def test_depend_err_middleware():
    """
    Verify that it is possible to write custom WebSocket middleware to catch errors
    """

    @websocket_middleware
    async def errorhandler(websocket: WebSocket, call_next):
        try:
            return await call_next()

    validations:
      required: true
  - type: textarea
    id: description
    attributes:
      label: Problem description
      description: |
        Please describe the problem as concisely as possible.
    validations:
      required: true
  - type: textarea
    id: context
    attributes:
      label: Context (optional)
      description: |

 * to the build service.
 */
interface TestFilesCleanupBuildServiceRootExtension {
    val projectStates: MapProperty<String, TestFilesCleanupProjectState>

    /**
     * Key is the path of a task, value is the possible report dirs it generates.
     */
    val taskPathToReports: MapProperty<String, List<File>>

0002 0.554 responseBodyEnd
0002 0.554 connectionReleased
0002 0.554 callEnd
0001 0.624 responseBodyEnd
0001 0.624 connectionReleased
0001 0.624 callEnd
```

The `EventListener.Factory` also makes it possible to limit metrics to a subset of calls. This one captures metrics on a random 10%:

```java
class MetricsEventListener extends EventListener {
  private static final Factory FACTORY = new Factory() {

////

//// tab | Python 3.10+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python
{!> ../../docs_src/app_testing/app_b_py310/main.py!}
```

////

//// tab | Python 3.8+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python
{!> ../../docs_src/app_testing/app_b/main.py!}
```

////

In the next sections you will see other options, configurations, and additional features.

/// tip

The next sections are **not necessarily "advanced"**.

And it's possible that for your use case, the solution is in one of them.

///

## Read the Tutorial first

## Current Behavior
<!--- If describing a bug, tell us what happens instead of the expected behavior -->
<!--- If suggesting a change/improvement, explain the difference from current behavior -->

## Possible Solution
<!--- Not obligatory, but suggest a fix/reason for the bug, -->
<!--- or ideas how to implement the addition or change -->

## Steps to Reproduce (for bugs)

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/security/tutorial001_an.py!}
```

////

//// tab | Python 3.8+ non-Annotated

/// tip

Prefer to use the `Annotated` version if possible.

///

```Python
{!> ../../docs_src/security/tutorial001.py!}
```

////

## Run it

/// info