@Override
 public FS2InMemoryObjectContainer clone() {
   FS2InMemoryObjectContainer clone = new FS2InMemoryObjectContainer();
   clone.metadata = metadata.clone();
   if (null != payload) {
     clone.payload = payload.clone();
   }
   return clone;
 }
 @Override
 public String toString() {
   return metadata.toString();
 }