docs: public ZooKeeperServer getZooKeeperServer() {
          if (zooKeeperServer == null) {
              String dataDirectory = System.getProperty("java.io.tmpdir");
              File dir = new File(dataDirectory, "zookeeper").getAbsoluteFile();
              try {
                  zooKeeperServer = new ZooKeeperServer(dir, dir, 2000);
              } catch (IOException e) {
                  throw new CitrusRuntimeException("Failed to create default zookeeper server", e);
              }
          }
  
          return zooKeeperServer;
      }