Added README.md

Author: limingxinleo

README.md

@@ -7,3 +7,72 @@
 ```
 composer require simple-swoole/rpc-multiplex
 ```
+
+## 配置 Server 端
+
+```php
+<?php
+
+declare(strict_types=1);
+
+return [
+    'mode' => SWOOLE_BASE,
+    'rpc' => [
+        'class_name' => Simps\RpcMultiplex\TcpServer::class,
+        'ip' => '0.0.0.0',
+        'port' => 9503,
+        'sock_type' => SWOOLE_SOCK_TCP,
+        'settings' => [
+            'worker_num' => 1,
+            // 以下参数除 package_max_length 外，其他不允许修改
+            'open_length_check' => true,
+            'package_length_type' => 'N',
+            'package_length_offset' => 0,
+            'package_body_offset' => 4,
+            'package_max_length' => 1024 * 1024 * 2,
+        ],
+    ],
+];
+
+```
+
+### 编写对应的服务端代码
+
+```php
+<?php
+
+namespace App\Service;
+
+class RpcService
+{
+    public function hello(string $name): string
+    {
+        return 'Hello ' . $name;
+    }
+}
+```
+
+## 直接使用 Client::instance 调用服务代码
+
+```php
+<?php
+
+use Simps\RpcMultiplex\Client;
+
+$data = Client::getInstance('127.0.0.1', 9503)->call('App\Service\RpcService', 'hello', 'World');
+
+var_dump($data->getResult()); // Hello World
+```
+
+因 `getInstance` 不会根据参数重新初始化，故以下代码获得的 `instance` 为同一个实例。
+
+```php
+<?php
+
+use Simps\RpcMultiplex\Client;
+
+$client1 = Client::getInstance('127.0.0.1', 9503);
+$client2 = Client::getInstance('127.0.0.1', 9504);
+```
+
+所以如果存在多个 RpcServer 时，需要使用继承，创建对应的单例。