* @deprecated For Android users, see the <a
   *     href="https://developer.android.com/training/data-storage" target="_blank">Data and File
   *     Storage overview</a> to select an appropriate temporary directory (perhaps {@code
   *     context.getCacheDir()}), and create your own directory under that. (For example, you might

}

func ptr[T any](a T) *T {
	return &a
}

// sleepContext sleeps for d duration or until ctx is done.
func sleepContext(ctx context.Context, d time.Duration) error {
	select {
	case <-ctx.Done():
		return ctx.Err()
	case <-time.After(d):
	}
	return nil
}

// helper type to return either item or error.
type itemOrErr[V any] struct {
	Item V
	Err  error

			Uname:    "rawr",
			Gname:    "dsnet",
			Format:   FormatGNU,
		}},
	}, {
		// BSD tar v3.1.2 and GNU tar v1.27.1 both rejects PAX records
		// with NULs in the key.
		file: "testdata/pax-nul-xattrs.tar",
		err:  ErrHeader,
	}, {
		// BSD tar v3.1.2 rejects a PAX path with NUL in the value, while
		// GNU tar v1.27.1 simply truncates at first NUL.
		// We emulate the behavior of BSD since it is strange doing NUL

For example:

* <a href="https://code.visualstudio.com/docs/python/environments#_select-and-activate-an-environment" class="external-link" target="_blank">VS Code</a>
* <a href="https://www.jetbrains.com/help/pycharm/creating-virtual-environment.html" class="external-link" target="_blank">PyCharm</a>

/// tip

  // class Holder<T> {
  //   void set(T data) {...}
  // }
  // Holder<List<?>> should *not* resolve the set() method to set(List<?> data).
  // Instead, it should create a capture of the wildcard so that set() rejects any List<T>.
  private static class WildcardCapturer {

    static final WildcardCapturer INSTANCE = new WildcardCapturer();

    private final AtomicInteger id;

    private WildcardCapturer() {

     IMPLIED, STATUTORY, OR OTHER. THIS INCLUDES, WITHOUT LIMITATION,
     WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR
     PURPOSE, NON-INFRINGEMENT, ABSENCE OF LATENT OR OTHER DEFECTS,
     ACCURACY, OR THE PRESENCE OR ABSENCE OF ERRORS, WHETHER OR NOT
     KNOWN OR DISCOVERABLE. WHERE DISCLAIMERS OF WARRANTIES ARE NOT
     ALLOWED IN FULL OR IN PART, THIS DISCLAIMER MAY NOT APPLY TO YOU.

 *
 * <pre>
 * Thread1: acquire(LockA) --X acquire(LockB)
 * Thread2: acquire(LockB) --X acquire(LockC)
 * ...
 * ThreadN: acquire(LockN) --X acquire(LockA)
 * </pre>
 *
 * <p>The implementation detects cycles by constructing a directed graph in which each lock
 * represents a node and each edge represents an acquisition ordering between two locks.
 *
 * <ul>

[Moshi](https://github.com/square/moshi) is a handy API for converting between JSON and Java objects. Here we're using it to decode a JSON response from a GitHub API.

Note that `ResponseBody.charStream()` uses the `Content-Type` response header to select which charset to use when decoding the response body. It defaults to `UTF-8` if no charset is specified.

=== ":material-language-kotlin: Kotlin"
    ```kotlin
      private val client = OkHttpClient()

</p>

<pre>
var limit = make(chan int, 3)

func main() {
	for _, w := range work {
		go func(w func()) {
			limit &lt;- 1
			w()
			&lt;-limit
		}(w)
	}
	select{}
}
</pre>

<h3 id="locks">Locks</h3>

<p>
The <code>sync</code> package implements two lock data types,
<code>sync.Mutex</code> and <code>sync.RWMutex</code>.
</p>

<p class="rule">

INFO:     Application startup complete.
```

</div>

<details markdown="1">
<summary>About the command <code>fastapi dev main.py</code>...</summary>

The command `fastapi dev` reads your `main.py` file, detects the **FastAPI** app in it, and starts a server using <a href="https://www.uvicorn.dev" class="external-link" target="_blank">Uvicorn</a>.

By default, `fastapi dev` will start with auto-reload enabled for local development.