typedef struct TF_Thread TF_Thread;

typedef struct TF_ThreadOptions {
  // Thread stack size to use (in bytes), zero implies that the system default
  // will be used.
  size_t stack_size;

  // Guard area size to use near thread stacks to use (in bytes), zero implies
  // that the system default will be used.
  size_t guard_size;

//
// `num_return_outputs` must be the number of return outputs added (i.e. the
// result of TF_ImportGraphDefOptionsNumReturnOutputs()).  If
// `num_return_outputs` is non-zero, `return_outputs` must be of length
// `num_return_outputs`. Otherwise it can be null.
TF_CAPI_EXPORT extern void TF_GraphImportGraphDefWithReturnOutputs(
    TF_Graph* graph, const TF_Buffer* graph_def,

    VLOG(1) << "Calling gradient function for '" << trace.op_type << "'";
    std::vector<Gradient*> in_gradients(trace.input_tensor_id.size());
    DCHECK(build_default_zeros_grads || zero_indices.empty());
    if (any_gradient_nonzero) {
      for (const auto i : zero_indices) {
        out_gradients[i] = trace.output_tensor_info[i].ZerosLike();
      }
      Status s;
      s = vspace.CallBackwardFunction(trace.op_type, trace.backward_function,

    unsigned char should_enable);

// Create a serialized tensorflow.ConfigProto proto, where:
//
// a) ConfigProto.optimizer_options.global_jit_level is set to ON_1 if
// `enable_xla_compilation` is non-zero, and OFF otherwise.
// b) ConfigProto.gpu_options.allow_growth is set to `gpu_memory_allow_growth`.
// c) ConfigProto.device_count is set to `num_cpu_devices`.
TF_CAPI_EXPORT extern TF_Buffer* TF_CreateConfig(

                             absl::Span<AbstractTensorHandle* const> inputs,
                             std::vector<AbstractTensorHandle*>* params);

// A callable that takes tensor inputs and returns zero or more tensor outputs.
using Model = std::function<Status(AbstractContext*,
                                   absl::Span<AbstractTensorHandle* const>,
                                   absl::Span<AbstractTensorHandle*>)>;