docs(docs): add additional code examples to README.md

- Added new code examples for sending messages asynchronously.
- Provided examples for creating a pool of messages and handling responses.

README.md

@@ -14,6 +14,7 @@
 ## Platform support
 
 [//]: # (https://github.com/dschep/ntfy)
+
 * [AnPush](./src/AnPush/README.md)
 * [Bark](./src/Bark/README.md)
 * [Chanify](./src/Chanify/README.md)
@@ -63,6 +64,8 @@ composer require guanguans/notify -v
 
 ## Usage example
 
+### Quick start
+
 ```php
 // 1. Create authenticator
 $authenticator = new Guanguans\Notify\DingTalk\Authenticator(
@@ -118,6 +121,21 @@ $response = $client
     ->json();
 ```
 
+### Asynchronous requests
+
+```php
+$promise = $client->sendAsync($message);
+$response = $promise->wait();
+```
+
+### Concurrent requests
+
+```php
+/** @var list<\Guanguans\Notify\Foundation\Contracts\Message> $messages */
+/** @var list<\Guanguans\Notify\Foundation\Response|\Psr\Http\Message\ResponseInterface> $responses */
+$responses = $client->pool($messages);
+```
+
 ## Testing
 
 ```bash