docs: def file_size(self, name, force_refresh=False):
          """Returns the size of the file.
  
             For efficiency this operation does not use locking, so may return
             inconsistent data. Use it for informational purposes.
          """
  
          uname, version = split_name(name)
  
          t = time.time()
          logger.debug('    querying size of %s', name)
          try:
              if not self.remote_store or (version is not None
                                           and not force_refresh):
                  try:
                      if self.local_store and self.local_store.exists(name):
                          return self.local_store.file_size(name)
                  except Exception:
                      if self.remote_store:
                          logger.warning("Error getting '%s' from local store",
                                         name, exc_info=True)
                      else:
                          raise
              if self.remote_store:
                  return self.remote_store.file_size(name)
              raise FiletrackerError("File not available: %s" % name)
          finally:
              logger.debug('    processed %s in %.2fs', name, time.time() - t)