docs: public void setInput(INDArray input) {
          this.input = input;
          if (this.layers == null) {
              init();
          }
          if (input != null) {
              if (input.length() == 0)
                  throw new IllegalArgumentException(
                          "Invalid input: length 0 (shape: " + Arrays.toString(input.shape()) + ")");
  
              // FIXME: int cast
              setInputMiniBatchSize((int) input.size(0));
          }
      }