void (*flush_caches)(const TF_Filesystem* filesystem);

  /// Starts a new transaction.
  ///
  /// An opaque transaction token is returned in `token`. Ownership of the token
  /// is in filesystem. Token will be freed in `end_transaction` call and any
  /// access to token after that is invalid.
  ///
  /// In case of error, plugins must set `status` to a value different than
  /// `TF_OK`, free memory allocated for `token` and return -1.