// the implementation of function.py/def_function.py to C++, and exposing a
// high-level API here. A strawman for what this interface could look like:
// TF_Value* TF_ExecuteFunction(TFE_Context*, TF_ConcreteFunction*, TF_Value*
// inputs, int num_inputs, TF_Status* status);
TF_CAPI_EXPORT extern TFE_Op* TF_ConcreteFunctionMakeCallOp(
    TF_ConcreteFunction* func, TFE_TensorHandle** inputs, int num_inputs,