code: public boolean isAllCancelled() {
          boolean res = true;
  
          if (N.notNullOrEmpty(upFutures)) {
              for (ContinuableFuture<?> preFuture : upFutures) {
                  res = res & preFuture.isAllCancelled();
              }
          }
  
          return isCancelled() && res;
      }
docs: Returns true if this future and all previous stage futures have been recursively cancelled, otherwise false is returned.
  
  @return