code: protected void doUnsubscribe (int oid, Subscriber<?> target)
      {
          DObject dobj = _ocache.get(oid);
          if (dobj != null) {
              dobj.removeSubscriber(target);
  
          } else if (_client.isFailureLoggable(Client.FailureType.UNSUBSCRIBE_NOT_PROXIED)) {
              log.info("Requested to remove subscriber from non-proxied object", "oid", oid,
                       "sub", target);
          }
      }
docs: This is guaranteed to be invoked via the invoker and can safely do main thread type things
  like call back to the subscriber.