Explain how to configure timeout in Readme

README.md

@@ -91,7 +91,7 @@ Migrating from yiisoft/yii2-swiftmailer
 
 To migrate from the deprecated [yiisoft/yii2-swiftmailer](https://github.com/yiisoft/yii2-swiftmailer) to this extension you need to update the application config.
 
-Swiftmailer default transport was the `SendmailTransport`, while this extension will default to a `NullTransport` (sends no mail). You can use the swiftmailer default like the following:
+Swiftmailer default transport was the `SendmailTransport`, while with this extension it will default to a `NullTransport` (sends no mail). You can use the swiftmailer default like the following:
 
    ```php
    'mailer' => [
@@ -101,6 +101,47 @@ Swiftmailer default transport was the `SendmailTransport`, while this extension
        ],
    ],
    ```
+With this extension, you do not have ability of directly setting timeout for example which with former extension could be set on configuration. The reason is, the underlying symfony extension defines its classes as final thereby discouraging inheritance and pushing towards composition. To achieve timeout (and other transport configurations), you will need to define factory class. below is a sample example for SMTP transport.
+
+```php
+namespace app\utils; //file is in utils folder of your application
+
+use Symfony\Component\Messenger\Transport\TransportFactoryInterface;
+
+class CustomSmtpFactory implements TransportFactoryInterface {
+    public function __construct(private TransportFactoryInterface $factory, private float $timeout)
+    {
+        $this->timeout = 120;
+    }
+
+    public function create(Dsn $dsn): TransportInterface
+    {
+        $result = $this->factory->create($dsn);
+        if ($result instanceof SmtpTransport) {
+            //Setup timeout to this or 
+            $result->getStream()->setTimeout($this->timeout);
+        }
+        return $result;
+    }
+
+    public function supports(Dsn $dsn): bool {
+        return $this->factory->supports($dsn);
+    }
+}
+```
+
+then in configuration, set the factory
+
+```php
+   'mailer' => [
+       'class' => yii\symfonymailer\Mailer::class,
+       'transportFactory' => app\utils\CustomSmtpFactory::class,
+        'transport' => [
+            'scheme' => 'smtp',
+            //other settings
+        ],
+   ],
+  ```
 
 Security implications of the DSN
 --------------------------------