for large models in PyTorch >= 2.1.0 with zipfile-based checkpoints.
filename_pattern (`str`, *optional*):
The pattern to look for the index file. Pattern must be a string that
can be formatted with `filename_pattern.format(suffix=...)` and must contain the keyword `suffix`
Defaults to `"model{suffix}.safetensors"`.
Returns:
`NamedTuple`: A named tuple with `missing_keys` and `unexpected_keys` fields.