add streaming response to helloworld service

helloworld/proto/helloworld.proto

@@ -6,6 +6,7 @@ option go_package = "./proto;helloworld";
 
 service Helloworld {
 	rpc Call(Request) returns (Response) {}
+	rpc Stream(StreamRequest) returns (stream StreamResponse) {};
 }
 
 // Call returns a personalised "Hello $name" response
@@ -16,3 +17,13 @@ message Request {
 message Response {
 	string message = 1;
 }
+
+// Stream returns a streaming helloworld response
+message StreamRequest {
+	string name = 1;
+        int64 messages = 2;
+}
+
+message StreamResponse {
+	string message = 1;
+}