Update Message structure: change Payload type to bytes and add Encoding field

services/data_service/internal/domain/message.go

@@ -1,6 +1,14 @@
 package domain
 
+type Encoding string
+
+const (
+	EncodingJSON     Encoding = "json"
+	EncodingProtobuf Encoding = "protobuf"
+)
+
 type Message struct {
 	Identifier Identifier
-	Payload    any
+	Payload    []byte
+	Encoding   Encoding
 }

services/data_service/internal/provider/binance/futures_websocket.go

@@ -141,7 +141,8 @@ func (b *FuturesWebsocket) readLoop() {
 				Provider: "binance_futures_websocket",
 				Subject:  container.Stream,
 			},
-			Payload: container.Data,
+			Payload:  []byte(container.Data),
+			Encoding: domain.EncodingJSON,
 		}
 
 		select {

services/data_service/internal/server/grpc_streaming_server.go

@@ -45,7 +45,8 @@ func (s *GRPCStreamingServer) ConnectStream(req *pb.ConnectStreamRequest, stream
 					Provider: msg.Identifier.Provider,
 					Subject:  msg.Identifier.Subject,
 				},
-				Payload: fmt.Sprintf("%v", msg.Payload),
+				Payload:  msg.Payload,
+				Encoding: string(msg.Encoding),
 			})
 
 			if err != nil {