TF_Status* status);
int64_t Tell(const TF_WritableFile* file, TF_Status* status);
void Flush(const TF_WritableFile* file, TF_Status* status);
void Sync(const TF_WritableFile* file, TF_Status* status);
void Close(const TF_WritableFile* file, TF_Status* status);
}  // namespace tf_writable_file

namespace tf_read_only_memory_region {
void Cleanup(TF_ReadOnlyMemoryRegion* region);
const void* Data(const TF_ReadOnlyMemoryRegion* region);

TF_CAPI_EXPORT extern void TF_NewWritableFile(const char* filename,
                                              TF_WritableFileHandle** handle,
                                              TF_Status* status);

// Closes the given handle and frees its memory. If there was a problem closing
// the file, it is indicated by status. Memory is freed in any case.
TF_CAPI_EXPORT extern void TF_CloseWritableFile(TF_WritableFileHandle* handle,

    const TF_SessionOptions* session_options, const TF_Buffer* run_options,
    const char* export_dir, const char* const* tags, int tags_len,
    TF_Graph* graph, TF_Buffer* meta_graph_def, TF_Status* status);

// Close a session.
//
// Contacts any other processes associated with the session, if applicable.
// May not be called after TF_DeleteSession().
TF_CAPI_EXPORT extern void TF_CloseSession(TF_Session*, TF_Status* status);

//
// Keeps references to Tensors watched via Watch and computed in Accumulate
// corresponding to output_tensors, and releases these references in its
// destructor. However, waiting until the destructor runs loses the memory
// efficiency of forward-mode autodiff. Instead, language bindings should call
// DeleteGradient as soon as a Tensor which was `Watch`ed or was an output
// Tensor passed to Accumulate goes out of scope.
//

  //
  // If false, a caller might implement pretty-printing by resolving and
  // iterating over the resulting tensor. This may still be viable if resolving
  // the handle loses information, but `SummarizeValue` would be more precise.
  virtual bool PreferCustomSummarizer() const { return false; }

  // Returns a string which summarizes the value of this TensorHandle, for

      : filename_(filename), file_(std::move(file)), ops_(ops) {}

  ~ModularWritableFile() override { ops_->cleanup(file_.get()); }

  Status Append(StringPiece data) override;
  Status Close() override;
  Status Flush() override;
  Status Sync() override;
  Status Name(StringPiece* result) const override;
  Status Tell(int64_t* position) override;

 private:
  std::string filename_;

  /// DEFAULT IMPLEMENTATION: No op.
  void (*sync)(const TF_WritableFile* file, TF_Status* status);

  /// Closes `*file`.
  ///
  /// Flushes all buffers and deallocates all resources.
  ///
  /// Calling `close` must not result in calling `cleanup`.
  ///
  /// Core TensorFlow will never call `close` twice.
  void (*close)(const TF_WritableFile* file, TF_Status* status);
} TF_WritableFileOps;