refactor: refactor message handling and improve job processing

- Rename `QueuedMessage` to `TaskMessage`
- Change variable type from pointer to value for `job`
- Replace `Bytes()` with `Payload()` method for message unmarshalling

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Author: appleboy

_example/producer-consumer/README.md

@@ -105,9 +105,9 @@ func main() {
     redisdb.WithAddr("127.0.0.1:6379"),
     redisdb.WithStreamName("foobar"),
     redisdb.WithGroup("foobar"),
-    redisdb.WithRunFunc(func(ctx context.Context, m core.QueuedMessage) error {
-      var v *job
-      if err := json.Unmarshal(m.Bytes(), &v); err != nil {
+    redisdb.WithRunFunc(func(ctx context.Context, m core.TaskMessage) error {
+      var v job
+      if err := json.Unmarshal(m.Payload(), &v); err != nil {
         return err
       }
       rets <- v.Message