Udpate triple readme

dubbo-samples-triple/README.MD

@@ -1,5 +1,11 @@
 ## Triple-Samples
 
+[Triple](https://dubbo.apache.org/zh/docs/concepts/rpc-protocol/) is an application layer's protocol based on HTTP/2,
+which supports interoperating with GRPC protocol naturally using Protobuf serialization. For non-protobuf applications,
+triple provides a compatible mode to upgrade without code modifications. So it is smooth to migrate to triple.
+
+This sample project contains most scenarios of Dubbo and non-Dubbo interoperation. 
+
 ### For beginners
 
 1. Start a zookeeper or config other registry in `org.apache.dubbo.sample.tri.ApiProvider`
@@ -9,18 +15,22 @@
 4. Run `org.apache.dubbo.sample.tri.ApiConsumer`
 
 ### For dubbo2 or non-prototbuf users
+
 Run `org.apache.dubbo.sample.tri.ApiWrapperProvider` and `org.apache.dubbo.sample.tri.ApiWrapperConsumer`.
 
 Dubbo3 will wrap request and response with a protobuf wrapper automatically, so it is still compatible with GRPC.
 
 ### For Dubbo developers
+
 Code under `test` folder is a general interoperation test suite for both Dubbo/Dubbo and Dubbo/GRPC.
 
 #### Dubbo/Dubbo test
+
 1. Run `org.apache.dubbo.sample.tri.TriGrpcProvider`
-2. Run `org.apache.dubbo.sample.tri.TriPbConsumerTest` , `org.apache.dubbo.sample.tri.TriWrapConsumerTest`  and `org.apache.dubbo.sample.tri.TriGenericTest`
+2. Run `org.apache.dubbo.sample.tri.TriPbConsumerTest` , `org.apache.dubbo.sample.tri.TriWrapConsumerTest`
+   and `org.apache.dubbo.sample.tri.TriGenericTest`
 
-#### DUbbo/GRPC test
+#### Dubbo/GRPC test
 
 ##### GRPC --> Dubbo
 
@@ -31,7 +41,3 @@ Code under `test` folder is a general interoperation test suite for both Dubbo/D
 
 1. Run `org.apache.dubbo.sample.tri.grpc.GrpcProvider`
 2. Run `org.apache.dubbo.sample.tri.TriPbConsumerTest`
-
-
-
-