prepare_v4 (#199)

move to v4 micro

Co-authored-by: Vasiliy Tolstov <v.tolstov@unistack.org>
Reviewed-on: #199
Co-authored-by: Evstigneev Denis <danteevstigneev@yandex.ru>
Co-committed-by: Evstigneev Denis <danteevstigneev@yandex.ru>

request.go

@@ -1,15 +1,12 @@
 package http
 
 import (
-	"go.unistack.org/micro/v3/codec"
-	"go.unistack.org/micro/v3/metadata"
-	"go.unistack.org/micro/v3/server"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/server"
 )
 
-var (
-	_ server.Request = &rpcRequest{}
-	_ server.Message = &rpcMessage{}
-)
+var _ server.Request = &rpcRequest{}
 
 type rpcRequest struct {
 	// rw          io.ReadWriter
@@ -23,14 +20,6 @@ type rpcRequest struct {
 	stream      bool
 }
 
-type rpcMessage struct {
-	payload     interface{}
-	codec       codec.Codec
-	header      metadata.Metadata
-	topic       string
-	contentType string
-}
-
 func (r *rpcRequest) ContentType() string {
 	return r.contentType
 }
@@ -66,23 +55,3 @@ func (r *rpcRequest) Stream() bool {
 func (r *rpcRequest) Body() interface{} {
 	return r.payload
 }
-
-func (r *rpcMessage) ContentType() string {
-	return r.contentType
-}
-
-func (r *rpcMessage) Topic() string {
-	return r.topic
-}
-
-func (r *rpcMessage) Body() interface{} {
-	return r.payload
-}
-
-func (r *rpcMessage) Header() metadata.Metadata {
-	return r.header
-}
-
-func (r *rpcMessage) Codec() codec.Codec {
-	return r.codec
-}