Add manual commit

Signed-off-by: Gabriele Santomaggio <g.santomaggio@gmail.com>

Author: Gsantomaggio

README.md

@@ -573,13 +573,13 @@ Super Stream supports [publish-filtering](#publish-filtering) and [consume-filte
 Offset tracking is supported for the Super Stream consumer. </br>
 In the same way as the standard stream, you can use the `SetAutoCommit` or `SetManualCommit` option to enable/disable the automatic offset tracking. </br>
 
-On the super stream consumer message handler is possible to identify the partition, the consumer and the offset. </br>:
+On the super stream consumer message handler is possible to identify the partition, the consumer and the offset: </br>
 ```golang
 	handleMessages := func(consumerContext stream.ConsumerContext, message *amqp.Message) {
 		....
-		consumerContext.Consumer.GetName()
-        consumerContext.Consumer.GetOffset()
-        consumerContext.Consumer.GetStreamName()
+    consumerContext.Consumer.GetName() // consumer name 
+    consumerContext.Consumer.GetOffset() // current offset
+    consumerContext.Consumer.GetStreamName() // stream name  (partition name )
         ....
 	}
 ```
@@ -588,6 +588,7 @@ Manual tracking API:
  - `consumerContext.Consumer.StoreOffset()`: stores the current offset.
  -  `consumerContext.Consumer.StoreCustomOffset(xxx)` stores a custom offset.
 
+Like the standard stream, you should avoid to store the offset for each single message: it will reduce the performances.
 
 
 ### Performance test tool