code: @Override
    public int readdir(String path, Pointer buff, FuseFillDir filter,
        @off_t long offset, FuseFileInfo fi) {
      final AlluxioURI turi = mPathResolverCache.getUnchecked(path);
      LOG.trace("readdir({}) [Alluxio: {}]", path, turi);
  
      try {
        final List<URIStatus> ls = mFileSystem.listStatus(turi);
        // standard . and .. entries
        filter.apply(buff, ".", null, 0);
        filter.apply(buff, "..", null, 0);
  
        for (final URIStatus file : ls) {
          filter.apply(buff, file.getName(), null, 0);
        }
      } catch (FileDoesNotExistException | InvalidPathException e) {
        LOG.debug("Failed to read directory {}, path does not exist or is invalid", path);
        return -ErrorCodes.ENOENT();
      } catch (Throwable t) {
        LOG.error("Failed to read directory {}", path, t);
        return AlluxioFuseUtils.getErrorCode(t);
      }
  
      return 0;
    }
docs: Reads the contents of a directory.
  
  @param path The FS path of the directory
  @param buff The FUSE buffer to fill
  @param filter FUSE filter
  @param offset Ignored in alluxio-fuse
  @param fi FileInfo data structure kept by FUSE
  @return 0 on success, a negative value on error