doc(main): Updated documentation

Author: ekkinox

README.md

@@ -105,10 +105,16 @@ grpcurl -plaintext -d '{"text":"hello"}' localhost:50051 example.ExampleService/
 - with `ExampleService/ExampleStreaming`:
 
 ```shell
-grpcurl -plaintext -d '{"text":"hello"}' localhost:50051 example.ExampleService/ExampleStreaming
+grpcurl -plaintext -d '@' localhost:50051 example.ExampleService/ExampleStreaming<<EOF
+{"text":"hello"}
+{"text":"world"}
+EOF
 {
   "text": "response from grpc-app: you sent hello"
 }
+{
+  "text": "response from grpc-app: you sent world"
+}
 ```
 
 You can use any gRPC clients, for example [Postman](https://learning.postman.com/docs/sending-requests/grpc/grpc-request-interface/) or [Evans](https://github.com/ktr0731/evans).