fix: correctly use bytebuffer slice in decodecontexts method

Signed-off-by: Tino Britty  <[email protected]>

Author: brittytino

core/src/main/java/kafka/automq/failover/FailoverListener.java

@@ -80,14 +80,15 @@ private Optional<FailoverContext[]> getContexts(MetadataDelta delta) {
             .map(kv -> kv.get(FailoverConstants.FAILOVER_KEY))
             .map(this::decodeContexts);
     }
-
-    private FailoverContext[] decodeContexts(ByteBuffer byteBuffer) {
-        byteBuffer.slice();
-        byte[] data = new byte[byteBuffer.remaining()];
-        byteBuffer.get(data);
+    
+        private FailoverContext[] decodeContexts(ByteBuffer byteBuffer) {
+        ByteBuffer slice = byteBuffer.slice();
+        byte[] data = new byte[slice.remaining()];
+        slice.get(data);
         return JsonUtils.decode(new String(data, StandardCharsets.UTF_8), FailoverContext[].class);
     }
 
+
     private void onContextsChange(FailoverContext[] contexts) {
         Set<FailedNode> oldFailedNodes = recovering.keySet();
         Set<FailedNode> newFailedNodes = Arrays.stream(contexts)