code: public boolean cancelAll(boolean mayInterruptIfRunning) {
          boolean res = true;
  
          if (N.notNullOrEmpty(upFutures)) {
              for (ContinuableFuture<?> preFuture : upFutures) {
                  res = res & preFuture.cancelAll(mayInterruptIfRunning);
              }
          }
  
          return cancel(mayInterruptIfRunning) && res;
      }
docs: Cancel this future and all the previous stage future recursively.
  
  @param mayInterruptIfRunning
  @return