to fix syntax err in the sample code: 'Close operations can also be asynchronous'
@@ -155,10 +155,10 @@ stringProducer.send("My message");
> Close operations can also be asynchronous:
> ```java
> producer.closeAsync()
-> .thenRun(() -> System.out.println("Producer closed"));
+> .thenRun(() -> System.out.println("Producer closed"))
> .exceptionally((ex) -> {
> System.err.println("Failed to close producer: " + ex);
-> return ex;
+> return null;
> });
> ```
