Asynchronous code just means that the language 💬 has a way to tell the computer / program 🤖 that at some point in the code, it 🤖 will have to wait for *something else* to finish somewhere else. Let's say that *something else* is called "slow-file" 📝.

So, during that time, the computer can go and do some other work, while "slow-file" 📝 finishes.

On top of that, an async framework could run some sync code in a threadpool (using `asyncio.run_in_executor`), but belonging to the same request.

#### Pushes

A push occurs when Istiod detects an update of some set of configuration is needed. This results in roughly the same result as a Request (new configuration is pushed to the client), and is just triggered by a different source.

```

### `HTMLResponse`

Takes some text or bytes and returns an HTML response, as you read above.

### `PlainTextResponse`

Takes some text or bytes and returns an plain text response.

```Python hl_lines="2  7  9"
{!../../../docs_src/custom_response/tutorial005.py!}
```

### `JSONResponse`

Takes some data and returns an `application/json` encoded response.

* Each application that you have running on your computer has some process behind it, each running program, each window, etc. And there are normally many processes running **at the same time** while a computer is on.
* There can be **multiple processes** of the **same program** running at the same time.

### Certificate Renewal

At some point in the future, each certificate would **expire** (about 3 months after acquiring it).

And then, there would be another program (in some cases it's another program, in some cases it could be the same TLS Termination Proxy) that would talk to Let's Encrypt, and renew the certificate(s).

        be available. However, if that file:// url references a
        file-share, as in the case of an NFS or SMB mount, that will
        be unavailable.

  So, offline mode has several implications, some of which may not be
  altogether obvious:

  * Localhost may be unavailable. Therefore, even locally installed
    server processes which work by conversing over a port may fail.

And these same full-stack generators were the base of the [**FastAPI** Project Generators](project-generation.md){.internal-link target=_blank}.

!!! info
    Flask-apispec was created by the same Marshmallow developers.

!!! check "Inspired **FastAPI** to"
    Generate the OpenAPI schema automatically, from the same code that defines serialization and validation.

## Client and SDK Generators - Sponsor

There are also some **company-backed** Client and SDK generators based on OpenAPI (FastAPI), in some cases they can offer you **additional features** on top of high-quality generated SDKs/clients.

        name = "CHECK_CLEAN_M2_ANDROID_USER_HOME"
        executionMode = BuildStep.ExecutionMode.ALWAYS
        scriptContent = if (os == Os.WINDOWS) {
            checkCleanDirWindows("%teamcity.agent.jvm.user.home%\\.m2\\repository") +
                checkCleanDirWindows("%teamcity.agent.jvm.user.home%\\.m2\\.gradle-enterprise") +
                checkCleanDirWindows("%teamcity.agent.jvm.user.home%\\.m2\\.develocity") +