code: @SuppressWarnings("unchecked")
      public List<?> multi(Iterable<?> ops) {
          if (method == null) throw new UnsupportedOperationException("multi operation must use zookeeper 3.4+");
          try {
              return (List<?>) method.invoke(_zk, ops);
          } catch (IllegalArgumentException e) {
              throw new UnsupportedOperationException("ops must be 'org.apache.zookeeper.Op'");
          } catch (IllegalAccessException e) {
              throw new UnsupportedOperationException(e);
          } catch (InvocationTargetException e) {
              throw new RuntimeException(e);
          }
      }
docs: wrapper for 3.3.x/3.4.x
  
  @param ops multi operations
  @return OpResult list