Update doc.

CHANGELOG.md

@@ -5,6 +5,7 @@
 - [#203](https://github.com/hyperf-cloud/hyperf/pull/203) [#236](https://github.com/hyperf-cloud/hyperf/pull/236) [#247](https://github.com/hyperf-cloud/hyperf/pull/247) [#252](https://github.com/hyperf-cloud/hyperf/pull/252) Added View component, support for Blade engine and Smarty engine. 
 - [#203](https://github.com/hyperf-cloud/hyperf/pull/203) Added support for Swoole Task mechanism.
 - [#245](https://github.com/hyperf-cloud/hyperf/pull/245) Added TaskWorkerStrategy and WorkerStrategy crontab strategies.
+- [#251](https://github.com/hyperf-cloud/hyperf/pull/251) Added coroutine memory driver for cache.
 - [#254](https://github.com/hyperf-cloud/hyperf/pull/254) Added support for array value of `RequestMapping::$methods`, `@RequestMapping(methods={"GET"})` and `@RequestMapping(methods={RequestMapping::GET})` are available now.
 - [#255](https://github.com/hyperf-cloud/hyperf/pull/255) Transfer `Hyperf\Utils\Contracts\Arrayable` result of Request to Response automatically, and added `text/plain` content-type header for string Response.
 - [#256](https://github.com/hyperf-cloud/hyperf/pull/256) If `Hyperf\Contract\IdGeneratorInterface` exist, the `json-rpc` client will generate a Request ID via IdGenerator automatically, and stored in Request attibute. Also added support for service register and health checks of `jsonrpc` TCP protocol.

doc/zh/cache.md

@@ -184,3 +184,51 @@ public function updateUserBook(int $id)
 }
 ```
 
+## 缓存驱动
+
+### Redis驱动
+
+`Hyperf\Cache\Driver\RedisDriver` 会把缓存数据存放到 `Redis` 中，需要用户配置相应的 `Redis配置`。此方式为默认方式。
+
+### 协程内存驱动
+
+> 本驱动乃Beta版本，请谨慎使用。
+
+如果您需要将数据缓存到 `Context` 中，可以尝试次驱动。例如以下应用场景：
+
+```php
+<?php
+use Hyperf\Cache\Annotation\Cacheable;
+
+class Demo {
+    
+    public function get($userId, $id)
+    {
+        return $this->getArray($userId)[$id] ?? 0;
+    }
+
+    /**
+     * @Cacheable(prefix="test", group="co")
+     * @param int $userId
+     * @return array
+     */
+    public function getArray($userId)
+    {
+        return $this->redis->hGetAll($userId);
+    }
+}
+```
+
+对应配置如下：
+
+```php
+<?php
+
+return [
+    'co' => [
+        'driver' => Hyperf\Cache\Driver\CoroutineMemoryDriver::class,
+        'packer' => Hyperf\Utils\Packer\PhpSerializerPacker::class,
+    ],
+];
+```
+