proc nnpack_conv2d(input, weight, bias: Tensor[float32]; padding, stride: Size2D): Tensor[
    float32] {.noinit, ...raises: [ValueError], tags: [], forbids: [].}

proc nnpack_conv2d_gradient[T](input, weight: Tensor[float32];
                               padding, stride: Size2D; grad_output: Tensor[T];
                               grad_input, grad_weight: var Tensor[T])