go mod tidy;

improve readme

Author: seeflood

README.md

@@ -59,6 +59,11 @@ For other features,see the demos below:
 | File            | ✅     | TODO                                                                  | [list](https://mosn.io/layotto/#/en/component_specs/file/oss)             | File API implementation|
 | Binding         | ✅     | TODO                                                                  | TODO                                                                      | Transparent data transmission API |
 
+### Extendability
+|  feature       | status |                         quick start                       |                         desc                         |
+|  ------------- | :----: | :--------------------------------------------------------:|------------------------------------------------------|
+| API plugin         | ✅     | [demo](https://mosn.io/layotto/#/en/start/api_plugin/helloworld)   |  You can add your own API ! |
+
 
 ### Actuator
 

docs/en/README.md

@@ -56,6 +56,11 @@ For other features,see the demos below:
 | File            | ✅     | TODO                                                                  | [list](https://mosn.io/layotto/#/en/component_specs/file/oss)             | File API implementation|
 | Binding         | ✅     | TODO                                                                  | TODO                                                                      | Transparent data transmission API |
 
+### Extendability
+|  feature       | status |                         quick start                       |                         desc                         |
+|  ------------- | :----: | :--------------------------------------------------------:|------------------------------------------------------|
+| API plugin         | ✅     | [demo](https://mosn.io/layotto/#/en/start/api_plugin/helloworld)   |  You can add your own API ! |
+
 ### Actuator
 
 |  feature       | status |                         quick start                       |                         desc                         |

docs/zh/README.md

@@ -61,6 +61,13 @@ Layotto 提供了多种语言版本的 SDK，SDK 通过 gRPC 与 Layotto 进行
 | File            | ✅     | [demo](https://mosn.io/layotto/#/zh/start/file/start)                 | [list](https://mosn.io/layotto/#/zh/component_specs/file/common)          | 提供访问文件的能力 |
 | Binding         | ✅     | TODO                                                                  | TODO                                                                      | 提供透传数据的能力 |
 
+
+### 可扩展性
+|  feature       | status |                         quick start                       |                         desc                         |
+|  ------------- | :----: | :--------------------------------------------------------:|------------------------------------------------------|
+| API 插件         | ✅     | [demo](https://mosn.io/layotto/#/zh/start/api_plugin/helloworld)   |  为 Layotto 添加您自己的API |
+
+
 ### Actuator
 
 |  feature       | status |                         quick start                       |               desc               |

go.mod

@@ -3,6 +3,7 @@ module mosn.io/layotto
 go 1.14
 
 require (
+	github.com/agrea/ptr v0.0.0-20180711073057-77a518d99b7b
 	github.com/alicebob/miniredis/v2 v2.13.3
 	github.com/dapr/components-contrib v1.4.0-rc2
 	github.com/dapr/kit v0.0.2-0.20210614175626-b9074b64d233