TF_Buffer** properties, int num_values, TF_Status* status);

// Helper to maintain a map between function names in a given
// FunctionDefLibrary and function definitions.
// Typical use case, is to look up an OpDef by type name.
typedef struct TF_FunctionLibraryDefinition TF_FunctionLibraryDefinition;

// Create NewFunctionLibraryDefinition.
TF_CAPI_EXPORT extern TF_FunctionLibraryDefinition*

  /// Prune the cache by removing files with expired blocks.
  void Prune() ABSL_LOCKS_EXCLUDED(mu_);

  bool BlockNotStale(const std::shared_ptr<Block>& block)
      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mu_);

  /// Look up a Key in the block cache.
  std::shared_ptr<Block> Lookup(const Key& key) ABSL_LOCKS_EXCLUDED(mu_);

  void MaybeFetch(const Key& key, const std::shared_ptr<Block>& block,