This is normally called a **webhook**.

## Webhooks steps

The process normally is that **you define** in your code what is the message that you will send, the **body of the request**.

You also define in some way at which **moments** your app will send those requests or events.

This includes, for example:

* Email notifications sent after performing an action:
    * As connecting to an email server and sending an email tends to be "slow" (several seconds), you can return the response right away and send the email notification in the background.
* Processing data:
    * For example, let's say you receive a file that must go through a slow process, you can return a response of "Accepted" (HTTP 202) and process the file in the background.

	// Channel *must* be closed to signal the end of the stream.
	// If the request context is canceled, the stream will no longer process requests.
	// Requests sent cannot be used any further by the called.
	Requests chan<- []byte

	muxID uint64
	ctx   context.Context
}

// Send a payload to the remote server.
func (s *Stream) Send(b []byte) error {
	if s.Requests == nil {

```Python
app.dependency_overrides = {}
```

/// tip

If you want to override a dependency only during some tests, you can set the override at the beginning of the test (inside the test function) and reset it at the end (at the end of the test function).

	// global Trace system to send HTTP request/response
	// and Storage/OS calls info to registered listeners.
	globalTrace = pubsub.New[madmin.TraceInfo, madmin.TraceType](8)

	// global Listen system to send S3 API events to registered listeners
	globalHTTPListen = pubsub.New[event.Event, pubsub.Mask](0)

	// global console system to send console logs to
	// registered listeners

    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> dep: Raise other exception
    end
    Note over dep: After yield
    opt Handle other exception
        dep -->> dep: Handle exception, can't change response. E.g. close DB session.
    end
```

/// info

							bucket, version.Name, err))
					}
				}

				if !send(result) {
					return
				}
			}

			// All versions resulted in 'ObjectNotFound/VersionNotFound'
			if versionNotFound == len(fivs.Versions) {
				return
			}

			send(healEntryDone(entry.name))

			// Wait and proceed if there are active requests
			waitForLowHTTPReq()
		}

///

## Await for messages and send messages

In your WebSocket route you can `await` for messages and send messages.

```Python hl_lines="48-52"
{!../../docs_src/websockets/tutorial001.py!}
```

You can receive and send binary, text, and JSON data.

## Try it

If your file is named `main.py`, run your application with:

Furthermore, because the Pod is torn down, we cannot even send any data at all (at least on most clusters, the `veth` is torn down upon Pod deletion).
Notably, this prevents us from sending a GOAWAY to notify peers we have shutdown.

As a result, while we meet our two must-haves (send and accept traffic throughout the entire pod lifetime), we do not have an optimal solution here yet.

}

/*
To clean up stale ztunnels

	we may need to ztunnel to send its (uid, bootid / boot time) to us
	so that we can remove stale entries when the ztunnel pod is deleted
	or when the ztunnel pod is restarted in the same pod (remove old entries when the same uid connects again, but with different boot id?)

	save a queue of what needs to be sent to the ztunnel pod and send it one by one when it connects.