docs: public ServiceDirectoryFuture asyncGetService(String serviceName, Watcher watcher){
          WatcherRegistration wcb = null;
          if (watcher != null) {
              wcb = new WatcherRegistration(serviceName, watcher);
          }
  
          ProtocolHeader header = new ProtocolHeader();
          header.setType(ProtocolType.GetService);
  
          GetServiceProtocol p = new GetServiceProtocol(serviceName);
          p.setWatcher(false);
          return connection.submitAsyncRequest(header, p,  wcb);
      }