codec rewrite

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

response.go

@@ -1,16 +1,23 @@
 package grpc
 
 import (
+	"io"
+
 	"github.com/unistack-org/micro/v3/codec"
 	"github.com/unistack-org/micro/v3/metadata"
 )
 
 type rpcResponse struct {
-	header metadata.Metadata
-	codec  codec.Codec
+	rw       io.ReadWriter
+	header   metadata.Metadata
+	codec    codec.Codec
+	endpoint string
+	service  string
+	method   string
+	target   string
 }
 
-func (r *rpcResponse) Codec() codec.Writer {
+func (r *rpcResponse) Codec() codec.Codec {
 	return r.codec
 }
 
@@ -21,7 +28,7 @@ func (r *rpcResponse) WriteHeader(hdr metadata.Metadata) {
 }
 
 func (r *rpcResponse) Write(b []byte) error {
-	return r.codec.Write(&codec.Message{
+	return r.codec.Write(r.rw, &codec.Message{
 		Header: r.header,
 		Body:   b,
 	}, nil)