xP: generate our own JSON marshallers

For non-trivial types, which are expensive to serialize
with encoding/json's struct reflection.

xP/xP.go

@@ -50,7 +50,7 @@ func relayReadJSON(conn net.Conn) []byte {
 		return nil
 	}
 
-	j, err := json.Marshal(&m)
+	j, err := m.MarshalJSON()
 	if err != nil {
 		log.Println("Event marshalling failed: " + err.Error())
 		return nil
@@ -126,7 +126,7 @@ func clientWriteJSON(ctx context.Context, ws *websocket.Conn, j []byte) bool {
 }
 
 func clientWriteError(ctx context.Context, ws *websocket.Conn, err error) bool {
-	j, err := json.Marshal(&RelayEventMessage{
+	j, err := (&RelayEventMessage{
 		EventSeq: 0,
 		Data: RelayEventData{
 			Interface: RelayEventDataError{
@@ -135,7 +135,7 @@ func clientWriteError(ctx context.Context, ws *websocket.Conn, err error) bool {
 				Error:      err.Error(),
 			},
 		},
-	})
+	}).MarshalJSON()
 	if err != nil {
 		log.Println("Event marshalling failed: " + err.Error())
 		return false