//
// We expose this here to allow fine-grained synchronization in multi-threaded
// workloads, which is required since the Python implementation depends on the
// above mutation methods. This allows us to prevent modifications to nodes in
// the graph after the session has been made aware of them.
TF_CAPI_EXPORT extern void TF_ExtendSession(TF_Session* session,
                                            TF_Status* status);

  /// The cache pruning thread that removes files with expired blocks.
  std::unique_ptr<TF_Thread, std::function<void(TF_Thread*)>> pruning_thread_;

  /// Notification for stopping the cache pruning thread.
  absl::Notification stop_pruning_thread_;

  /// Guards access to the block map, LRU list, and cached byte count.
  mutable absl::Mutex mu_;

  /// The block map (map from Key to Block).