ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);

  TF_DeleteFunction(grad_func);

  const StackTracesMap* func_stack_traces;
  const StackTracesMap* grad_stack_traces;

  {
    mutex_lock l(host_graph_->mu);
    auto flib_def = host_graph_->graph.flib_def();
    func_stack_traces = flib_def.GetStackTraces(func_name_);
    grad_stack_traces = flib_def.GetStackTraces("MyGrad");
  }

    the graphical user interface (GUI) of TensorFlow Debugger (tfdbg), is now in
    alpha.
*   Experimental support for reading a sqlite database as a `Dataset` with new
    `tf.contrib.data.SqlDataset`.
*   Distributed Mutex / CriticalSection added to
    `tf.contrib.framework.CriticalSection`.
*   Better text processing with `tf.regex_replace`.
*   Easy, efficient sequence input with
    `tf.contrib.data.bucket_by_sequence_length`

  return nullptr;
#else
  TF_Library* lib_handle = new TF_Library;
  static tensorflow::mutex mu(tensorflow::LINKER_INITIALIZED);
  static std::unordered_map<std::string, void*>* loaded_libs =
      new std::unordered_map<std::string, void*>();
  tensorflow::Env* env = tensorflow::Env::Default();
  {
    tensorflow::mutex_lock lock(mu);
    auto it = loaded_libs->find(library_filename);
    if (it != loaded_libs->end()) {

  TFE_Context* context_ TF_GUARDED_BY(execution_mutex_);
  const char* operation_name_ TF_GUARDED_BY(execution_mutex_);
  absl::optional<int64_t> step_id_ TF_GUARDED_BY(execution_mutex_) =
      absl::nullopt;
  std::vector<TFE_TensorHandle*> op_inputs_ TF_GUARDED_BY(execution_mutex_);
  const TFE_OpAttrs* attributes_ TF_GUARDED_BY(execution_mutex_);
  int expected_max_outputs_ TF_GUARDED_BY(execution_mutex_);

}

int TF_GraphNumFunctions(TF_Graph* g) {
  tensorflow::mutex_lock l(g->mu);
  return g->graph.flib_def().num_functions();
}

int TF_GraphGetFunctions(TF_Graph* g, TF_Function** funcs, int max_func,
                         TF_Status* status) {
  tensorflow::FunctionDefLibrary lib;
  {
    tensorflow::mutex_lock l(g->mu);
    lib = g->graph.flib_def().ToProto();
  }

typedef struct GcsFileStat {
  TF_FileStatistics base;
  int64_t generation_number;
} GcsFileStat;

typedef struct GCSFile {
  google::cloud::storage::Client gcs_client;  // owned
  bool compose;
  absl::Mutex block_cache_lock;
  std::shared_ptr<RamFileBlockCache> file_block_cache
      ABSL_GUARDED_BY(block_cache_lock);
  uint64_t block_size;  // Reads smaller than block_size will trigger a read