ggml_backend_eval_callbackFunction typedef
        ggml_backend_eval_callbackFunction =
     Bool Function(Int node_index, Pointer<ggml_tensor>  t1, Pointer<ggml_tensor>  t2, Pointer<Void>  user_data)
    
    
    
Implementation
typedef ggml_backend_eval_callbackFunction = ffi.Bool Function(
    ffi.Int node_index,
    ffi.Pointer<ggml_tensor> t1,
    ffi.Pointer<ggml_tensor> t2,
    ffi.Pointer<ffi.Void> user_data);