void (*create_dir)(const TF_Filesystem* filesystem, const char* path,
                     TF_Status* status);

  /// Creates the directory specified by `path` and all needed ancestors.
  ///
  /// Plugins:
  ///   * Must set `status` to `TF_OK` if directory was created.
  ///   * Must set `status` to `TF_FAILED_PRECONDITION` if `path` is invalid or
  ///     if it exists but is not a directory.

    that this class is not strictly immutable as it has stateful members like
    the connection pool and cache.

 *  **Get and Set prefixes are now avoided.** With ubiquitous builders
    throughout OkHttp these accessor prefixes aren't necessary. Previously
    OkHttp used _get_ and _set_ prefixes sporadically which make the API
    inconsistent and awkward to explore.