// Get configuration key and value using coordination service.
// The config key must be set before getting its value. Getting value of
// non-existing config keys will result in errors.
// If `timeout_in_ms=0`, this call will block until the key-value is set or the
// worker shuts down.
TF_CAPI_EXPORT extern void TFE_GetConfigKeyValue(TFE_Context* ctx,

  /// Returns a list of valid configuration keys in `keys` array and number of
  /// keys in `num_keys`. Ownership of the buffers in `keys` are transferred to
  /// caller and needs to be freed using relevant filesystem allocation API.
  ///
  /// Plugins:
  ///   * Must set `status` to `TF_OK` on success. If there are no configurable
  ///     keys, `num_keys` should be set to 0

  tensorflow::ShapeRefiner refiner TF_GUARDED_BY(mu);

  // Maps from name of an operation to the Node* in 'graph'.
  std::unordered_map<tensorflow::string, tensorflow::Node*> name_map
      TF_GUARDED_BY(mu);

  // The keys of this map are all the active sessions using this graph. Each
  // value records whether the graph has been mutated since the corresponding
  // session has been run (this is detected in RecordMutation function). If the