sufficient copyright rights in its Contribution, if any, to grant
  the copyright license set forth in this Agreement.

  e) Notwithstanding the terms of any Secondary License, no
  Contributor makes additional grants to any Recipient (other than
  those set forth in this Agreement) as a result of such Recipient's
  receipt of the Program under the terms of a Secondary License
  (if permitted under the terms of Section 3).

    * Tell me how you use FastAPI (I love to hear that).
    * Hear when I make announcements or release new tools.
    * You can also <a href="https://x.com/fastapi" class="external-link" target="_blank">follow @fastapi on X (Twitter)</a> (a separate account).
* <a href="https://www.linkedin.com/in/tiangolo/" class="external-link" target="_blank">Follow me on **LinkedIn**</a>.

> and you can rely on it after doing initial sanity check and targeted local testing.

### Copyright and License

When updating/modifying a file, please do not make changes to the copyright header.

When creating a new file, please make sure to add a header as defined below.

#### Required Files for Copyright Headers:

- Source code files (e.g., `.java`, `.kt`, `.groovy`).

> Modern versions of Python have support for **"asynchronous code"** using something called **"coroutines"**, with **`async` and `await`** syntax.

That should make more sense now. ✨

All that is what powers FastAPI (through Starlette) and what makes it have such an impressive performance.

## Very Technical Details { #very-technical-details }

/// warning

You can probably skip this.

          latch2.countDown()
        }
      }
    val request2Listener: EventListener =
      object : EventListener() {
        override fun connectStart(
          call: Call,
          inetSocketAddress: InetSocketAddress,
          proxy: Proxy,
        ) {
          // Let request1 proceed to make a connection.
          latch1.countDown()

You will see examples of this in the next chapters, about relational and NoSQL databases, security, etc.

## **FastAPI** compatibility { #fastapi-compatibility }

The simplicity of the dependency injection system makes **FastAPI** compatible with:

* all the relational databases
* NoSQL databases
* external packages
* external APIs
* authentication and authorization systems
* API usage monitoring systems

/// note

Having a default value of any type, including `None`, makes the parameter optional (not required).

///

## Required parameters { #required-parameters }

When we don't need to declare more validations or metadata, we can make the `q` query parameter required just by not declaring a default value, like:

```Python
q: str
```

instead of:

## Restarts { #restarts }

Similar to making sure your application is run on startup, you probably also want to make sure it is **restarted** after failures.

### We Make Mistakes { #we-make-mistakes }

We, as humans, make **mistakes**, all the time. Software almost *always* has **bugs** hidden in different places. 🐛

	queryValue := url.Values{}
	queryValue.Set("uploads", "")
	queryValue.Set("prefix", prefix)
	queryValue.Set("delimiter", delimiter)
	queryValue.Set("key-marker", keyMarker)
	queryValue.Set("upload-id-marker", uploadIDMarker)
	queryValue.Set("max-uploads", maxUploads)
	return makeTestTargetURL(endPoint, bucketName, "", queryValue)
}

// return URL for a listing parts on a given upload id.

	copyPartsMetadata := make([]FileInfo, len(partsMetadata))
	for i := range latestDisks {
		if latestDisks[i] == nil {
			continue
		}
		copyPartsMetadata[i] = partsMetadata[i]
	}

	for i := range outDatedDisks {
		if outDatedDisks[i] == nil {
			continue
		}
		// Make sure to write the FileInfo information
		// that is expected to be in quorum.