example: improve stream example (#110)

Author: Leoyoungxh

examples/features/stream/client/main.go

@@ -86,7 +86,7 @@ func clientStream(ctx context.Context, proxy pb.TestStreamClientProxy) error {
 		// Call Send to continuously send data.
 		if err = streamClient.Send(&pb.HelloReq{Msg: fmt.Sprintf("ping : %v", i)}); err != nil {
 			log.ErrorContextf(ctx, "ClientStream send error: %v", err)
-			break
+			return err
 		}
 	}
 
@@ -134,7 +134,7 @@ func bidirectionalStream(ctx context.Context, proxy pb.TestStreamClientProxy) er
 		// The client send request data to the server 5 times using a for loop.
 		if err = streamClient.Send(&pb.HelloReq{Msg: "ping: " + strconv.Itoa(i)}); err != nil {
 			log.ErrorContextf(ctx, "BidirectionalStream Send message error: %v", err)
-			break
+			return err
 		}
 	}
 
@@ -153,6 +153,7 @@ func bidirectionalStream(ctx context.Context, proxy pb.TestStreamClientProxy) er
 		}
 		if err != nil {
 			log.ErrorContextf(ctx, "BidirectionalStream receive error from server: %v", err)
+			break
 		}
 		log.InfoContextf(ctx, "BidirectionalStream reply message is: %s", rsp.GetMsg())
 	}