code: function _folderRead(item, stat, dirpath, callback, err, files) {
    if (err) return callback(err);
    async.map(
      files,
      _readChild.bind(null, stat, dirpath),
      _childrenRead.bind(null, item, callback)
    );
  }
docs: Ensures each child of the read directory may provide its data.
  @param {Object} item - Object that is supposed to be updated with
  discovered data.
  @param {Function} stat - Function of fs module fs.stat or fs.lstat.
  @param {String} dirpath - Path of the read directory on file system.
  @param {Function} callback - Callback that expects a possible error
  and array of child data.
  @param {*} err - Possible error passed by caller.
  @param {String[]} files - List of file names contained in the
  directory.