client = mqtt.Client(client_id="myclientid",clean_session=False)

client.on_connect = on_connect
client.on_message = on_message

client.connect("localhost",1883,60)
client.loop_forever()
```

Execute this example python program to watch for MQTT events on the console.

```py
python mqtt.py
```

        // Setting onConnect to null should work
        request.onConnect(null);

        assertNotNull(request);
    }

    @Test
    public void testMultipleOnConnectCalls() {
        CurlRequest request = new CurlRequest(Method.GET, "https://example.com");

        // Multiple onConnect calls should work (last one wins)
        request.onConnect((req, conn) -> conn.setConnectTimeout(1000));

// Op is operation type messages.
type Op uint8

// HandlerID is the ID for the handler of a specific type.
type HandlerID uint8

const (
	// OpConnect is a connect request.
	OpConnect Op = iota + 1

	// OpConnectResponse is a response to a connect request.
	OpConnectResponse

	// OpPing is a ping request.
	// If a mux id is specified that mux is pinged.

        if (!healthResponse.isTimedOut()) {
            onConnectListenerList.forEach(l -> {
                try {
                    l.onConnect();
                } catch (final Exception e) {
                    logger.warn("Failed to invoke onConnect listener: listener={}", l.getClass().getName(), e);
                }
            });

            connected = true;
        } else {

            } else if (entry.getValue().length == 1) {
                curlRequest.param(entry.getKey(), entry.getValue()[0]);
            }
        });
        try (final CurlResponse curlResponse = curlRequest.onConnect((req, con) -> {
            con.setDoOutput(true);
            if (httpMethod != Method.GET && request.getContentLength() > 2) {

        }

        final ObjectMapper mapper = new ObjectMapper();
        final AtomicBoolean resetJobs = new AtomicBoolean(false);
        try (CurlResponse response = ComponentUtil.getCurlHelper().post("/_bulk").onConnect((req, con) -> {
            con.setDoOutput(true);
            try (final BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(tempFile)));

        fesenClient.addOnConnectListener(listener);

        // Manually invoke listeners as if connect() succeeded
        fesenClient.onConnectListenerList.forEach(l -> {
            try {
                l.onConnect();
            } catch (Exception e) {
                fail("Listener should not throw: " + e.getMessage());
            }
        });

        assertTrue("Listener should have been called", listenerCalled.get());

    /**
     * Sets the connection builder for customizing the connection.
     *
     * @param connectionBuilder the connection builder
     * @return this CurlRequest instance
     */
    public CurlRequest onConnect(final BiConsumer<CurlRequest, HttpURLConnection> connectionBuilder) {
        this.connectionBuilder = connectionBuilder;
        return this;
    }

    /**
     * Adds a request parameter.
     *

	}

	var message message
	_, _, err = message.parse(msg)
	if err != nil {
		writeErr(fmt.Errorf("error parsing grid connect: %w", err))
		return
	}
	if message.Op != OpConnect {
		writeErr(fmt.Errorf("unexpected connect op: %v", message.Op))
		return
	}
	var cReq connectReq
	_, err = cReq.UnmarshalMsg(message.Payload)
	if err != nil {

			}
			c.updateState(StateConnectionError)
			time.Sleep(sleep)
		}
		if err != nil {
			retry(err)
			continue
		}
		// Send connect message.
		m := message{
			Op: OpConnect,
		}
		req := connectReq{
			Host: c.Local,
			ID:   c.id,
			Time: time.Now(),
		}
		req.addToken(c.authFn)
		err = c.sendMsg(conn, m, &req)
		if err != nil {
			retry(err)
			continue