Golang：将字节插入[]字节

I'm working on GRPC stream, In server side, I receive the multiple byte inside the for loop, I want to merge in a single array of byte (I tried append method but not use), Here I have attached my sample code. Any one guide me.

Example code

func (s *ServerGRPC) Upload(stream pb.GuploadService_UploadServer) (err error) {

for {
        resp, err := stream.Recv()

        if err != nil {
            if err == io.EOF {
                goto END
            }

            err = errors.Wrapf(err,
                "failed unexpectadely while reading chunks from stream")
            return err
        }

        for _, result := range resp.Content {

            fmt.Println("result ====>>>", result)

          //Actual Output
          //result ====>>> 136
          //result ====>>> 84
          //result ====>>> 232
          //result ====>>> 12

          //Expectation
          //result ===> [136 84 232 12] 

        }

    }
        s.logger.Info().Msg("upload received")

    END:
        err = stream.SendAndClose(&pb.UploadStatus{
            Message: "Upload received with success",
            Code:    pb.UploadStatusCode_Ok,
        })
        if err != nil {
            err = errors.Wrapf(err,
                "failed to send status code")
            return
        }

        return
    }

You are appending to Sample but printing req.Content
There is nothing wrong with merging slices. if just have to print Sample to see merged result.

func (s *ServerGRPC) Upload(stream pb.GuploadService_UploadServer) (err error) {

var respBytes []byte
for {
        resp, err := stream.Recv()

        if err != nil {
            if err == io.EOF {
                goto END // you can use break here
            }

            err = errors.Wrapf(err,
                "failed unexpectadely while reading chunks from stream")
            return err
        }

        for _, result := range resp.Content {

            fmt.Println("result ====>>>", result)
            respBytes = append(respBytes, result)

        }
    }
        s.logger.Info().Msg("upload received")
        // print respBytes here
    END:
        err = stream.SendAndClose(&pb.UploadStatus{
            Message: "Upload received with success",
            Code:    pb.UploadStatusCode_Ok,
        })
        if err != nil {
            err = errors.Wrapf(err,
                "failed to send status code")
            return
        }

        return
    }