[#83] services/util: Implement response service

Create response package. Implement response Service that sets values of
response meta header.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/util/response/client_stream.go

@@ -0,0 +1,45 @@
+package response
+
+import (
+	"github.com/nspcc-dev/neofs-node/pkg/services/util"
+	"github.com/pkg/errors"
+)
+
+// ClientMessageStreamer represents client-side message streamer
+// that sets meta values to the response.
+type ClientMessageStreamer struct {
+	cfg *cfg
+
+	send util.RequestMessageWriter
+
+	close util.ClientStreamCloser
+}
+
+// Recv calls send method of internal streamer.
+func (s *ClientMessageStreamer) Send(req interface{}) error {
+	return errors.Wrapf(
+		s.send(req),
+		"(%T) could not send the request", s)
+}
+
+// CloseAndRecv closes internal stream, receivers the response,
+// sets meta values and returns the result.
+func (s *ClientMessageStreamer) CloseAndRecv() (util.ResponseMessage, error) {
+	resp, err := s.close()
+	if err != nil {
+		return nil, errors.Wrapf(err, "(%T) could not close stream and receive response", s)
+	}
+
+	setMeta(resp, s.cfg)
+
+	return resp, nil
+}
+
+// CreateRequestStreamer wraps stream methods and returns ClientMessageStreamer instance.
+func (s *Service) CreateRequestStreamer(sender util.RequestMessageWriter, closer util.ClientStreamCloser) *ClientMessageStreamer {
+	return &ClientMessageStreamer{
+		cfg:   s.cfg,
+		send:  sender,
+		close: closer,
+	}
+}