For example:

	// #cgo noescape cFunctionName

When a Go function calls a C function, it prepares for the C function to
call back to a Go function. The #cgo nocallback directive may be used to
tell the compiler that these preparations are not necessary.
If the nocallback directive is used and the C function does call back into
Go code, the program will panic.

For example:

We are not restricted to having only one dependency that can return that type of data.

///

## Other models { #other-models }

You can now get the current user directly in the *path operation functions* and deal with the security mechanisms at the **Dependency Injection** level, using `Depends`.

And you can use any model or data for the security requirements (in this case, a Pydantic model `User`).

 * **Route**: address, proxy, socketAddress
 * **TlsVersion**: javaName

#### Renamed Functions

* **Headers.of()**: for symmetry with `listOf()`, `setOf()`, etc., we’ve replaced
  `Headers.of(String...)` with `headersOf(vararg String)`.

#### Extension Functions

We’ve migrated from static functions to extension functions where we think they fit.

| Java                                | Kotlin                          |

    <function-class>org.codelibs.fess.taglib.FessFunctions</function-class>
    <function-signature>java.lang.String mltForm()</function-signature>
    <example>
      ${fe:mltForm()}
    </example>
  </function>

  <function>
    <description>
      Returns a hidden form for Geo.
    </description>
    <name>geoForm</name>
    <function-class>org.codelibs.fess.taglib.FessFunctions</function-class>

Added context aware dial functions for TCP, UDP, IP and Unix networks....

### Otras funciones de utilidad

Cualquier otra función de utilidad que llames directamente puede ser creada con `def` normal o `async def` y FastAPI no afectará la forma en que la llames.

Esto contrasta con las funciones que FastAPI llama por ti: *path operation functions* y dependencias.

Maybe you need to start a new version, or you just got tired of running it. 🤷

///

### Lifespan function { #lifespan-function }

The first thing to notice, is that we are defining an async function with `yield`. This is very similar to Dependencies with `yield`.

{* ../../docs_src/events/tutorial003.py hl[14:19] *}

The first part of the function, before the `yield`, will be executed **before** the application starts.

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"fmt"
	"os"
	"path"
)

// Wrapper functions to os.RemoveAll, which calls reliableRemoveAll
// this is to ensure that if there is a racy parent directory
// create in between we can simply retry the operation.
func removeAll(dirPath string) (err error) {

    return {"fresh_value": fresh_value}
```

////

## Recap { #recap }

Apart from all the fancy words used here, the **Dependency Injection** system is quite simple.

Just functions that look the same as the *path operation functions*.

But still, it is very powerful, and allows you to declare arbitrarily deeply nested dependency "graphs" (trees).

/// tip

All this might not seem as useful with these simple examples.

   * generated by applying the specified functions. If multiple inputs are mapped to the same row
   * and column pair, they will be combined with the specified merging function in encounter order.
   *
   * <p>The returned {@code Collector} will throw a {@code NullPointerException} at collection time
   * if the row, column, value, or merging functions return null on any input.
   *