docs: function hasAttr(fs, path, attr, callback) {
    fs.getxattr(path, attr, function(err, attrVal) {
      // File doesn't exist locally at all
      if(err && err.code === 'ENOENT') {
        return callback(null, false);
      }
  
      // Deal with unexpected error
      if(err && err.code !== 'ENOATTR') {
        return callback(err);
      }
  
      callback(null, !!attrVal);
    });
  }