@Override
 public void fail(Object id) {
   ((Set) RegisteredGlobalState.getState(_failed)).add(id);
 }
 public boolean isFailed(Object id) {
   return ((Set) RegisteredGlobalState.getState(_failed)).contains(id);
 }
 @Override
 public void ack(Object id) {
   ((Set) RegisteredGlobalState.getState(_acked)).add(id);
 }
 public AckFailMapTracker() {
   _acked = RegisteredGlobalState.registerState(new HashSet());
   _failed = RegisteredGlobalState.registerState(new HashSet());
 }