code: public Future<Void> waitUntilReadyFuture() {
          try {
              return getRegistryRemote().waitUntilReadyFuture();
          } catch (NotAvailableException ex) {
              return FutureProcessor.canceledFuture(null, ex);
          }
      }
docs: Method blocks until the registry is not handling any tasks and is currently consistent.
  <p>
  Note: If you have just modified the registry this method can maybe return immediately if the task is not yet received by the registry controller.
  So you should prefer the futures of the modification methods for synchronization tasks.
  
  @return a future which is finished if the registry is ready.