Return value format of `epath.Path.stat()` does not match `pathlib.Path.stat()`

Format of `epath.Path.stat()`:

https://github.com/google/etils/blob/v1.9.2/etils/epath/stat_utils.py#L21-L39

Format of `pathlib.Path.stat()`:

https://docs.python.org/3/library/os.html#os.stat_result

Apart from the attribute name differences, the attribute that I am currently interested in is `pathlib.Path.stat().st_mtime_ns`, which represents mtime in nanoseconds. However, `epath.Path.stat()` does not return this information.