Dependent on torch.Graph._export_onnx, large model export requires specifying a target path to store the model and weights proto. Right now this path is fixed as "".

https://github.com/microsoft/onnx-script/blob/4986a4be9f8ff1b0e2b7bdde738836574f90e900/onnxscript/function_libs/torch_aten/graph_building.py#L475