When you want to call an `async def` function, you have to "await" it. So, this won't work:

```Python
# This won't work, because get_burgers was defined with: async def
burgers = get_burgers(2)
```

---

We want to get the `current_user` *only* if this user is active.

So, we create an additional dependency `get_current_active_user` that in turn uses `get_current_user` as a dependency.

Both of these dependencies will just return an HTTP error if the user doesn't exist, or if is inactive.

So, in our endpoint, we will only get a user if the user exists, was correctly authenticated, and is active:

Conversations in the chat systems are also not as easily searchable as in GitHub, so questions and answers might get lost in the conversation. And only the ones in GitHub count to become a [FastAPI Expert](fastapi-people.md#fastapi-experts){.internal-link target=_blank}, so you will most probably receive more attention in GitHub.

So, what we will do next is add the code to document how that *external API* should look like to receive the callback from *your API*.

**FastAPI** is fully compatible with (and based on) <a href="https://www.starlette.io/" class="external-link" target="_blank"><strong>Starlette</strong></a>. So, any additional Starlette code you have, will also work.

`FastAPI` is actually a sub-class of `Starlette`. So, if you already know or use Starlette, most of the functionality will work the same way.

    assertThat(pool.connectionCount()).isEqualTo(1)

    // Decrease the connection's max so that another connection is needed
    updateMaxConcurrentStreams(http2Connection, 4)
    assertThat(pool.connectionCount()).isEqualTo(2)

    // Increase the connection's max so that the new connection is no longer needed
    updateMaxConcurrentStreams(http2Connection, 5)

2. By using a `with` block, we make sure that the file-like object is closed after the generator function is done. So, after it finishes sending the response.
3. This `yield from` tells the function to iterate over that thing named `file_like`. And then, for each part iterated, yield that part as coming from this generator function.

    So, it is a generator function that transfers the "generating" work to something else internally.

| HOST_PROBE_SNAT_IP | "169.254.7.127" | Applied to SNAT host probe packets, so they can be identified/skipped podside. Any link-local address in the 169.254.0.0/16 block can be used |
| HOST_PROBE_SNAT_IPV6 | "fd16:9254:7127:1337:ffff:ffff:ffff:ffff" | IPv6 link local ranges are designed to be collision-resistant by default, and so this probably never needs to be overridden |

## Sidecar Mode Implementation Details

    * So, by using FastAPI you are saving development time, bugs, lines of code, and you would probably get the same performance (or better) you would...

### About `**user_in.dict()`

#### Pydantic's `.dict()`

`user_in` is a Pydantic model of class `UserIn`.

Pydantic models have a `.dict()` method that returns a `dict` with the model's data.

So, if we create a Pydantic object `user_in` like:

```Python
user_in = UserIn(username="john", password="secret", email="******@****.***")
```

and then we call:

```Python
user_dict = user_in.dict()
```