Function convert 

pub fn convert(
    model_id: &str,
    safetensors_path: &Path,
    config: &TabFMConfig,
    opts: &ConvertOptions,
    output_path: &Path,
) -> Result<()>

Read a single (already pytorch_model.bin -> safetensors converted) checkpoint, convert every tensor, and write a GGUF file to output_path.