remove using global map for default codecs (#223)

client/noop.go

@@ -15,11 +15,6 @@ import (
 	"go.unistack.org/micro/v4/tracer"
 )
 
-// DefaultCodecs will be used to encode/decode data
-var DefaultCodecs = map[string]codec.Codec{
-	"application/octet-stream": codec.NewCodec(),
-}
-
 type noopClient struct {
 	funcCall   FuncCall
 	funcStream FuncStream

client/options.go

@@ -161,7 +161,7 @@ func NewOptions(opts ...Option) Options {
 	options := Options{
 		Context:     context.Background(),
 		ContentType: DefaultContentType,
-		Codecs:      DefaultCodecs,
+		Codecs:      make(map[string]codec.Codec),
 		CallOptions: CallOptions{
 			Context:        context.Background(),
 			Backoff:        DefaultBackoff,

server/noop.go

@@ -6,7 +6,6 @@ import (
 	"sync"
 	"time"
 
-	"go.unistack.org/micro/v4/codec"
 	"go.unistack.org/micro/v4/logger"
 	"go.unistack.org/micro/v4/register"
 	maddr "go.unistack.org/micro/v4/util/addr"
@@ -14,11 +13,6 @@ import (
 	"go.unistack.org/micro/v4/util/rand"
 )
 
-// DefaultCodecs will be used to encode/decode
-var DefaultCodecs = map[string]codec.Codec{
-	"application/octet-stream": codec.NewCodec(),
-}
-
 type rpcHandler struct {
 	opts    HandlerOptions
 	handler interface{}