code: function storage (key) {
      var dk = hypercore.discoveryKey(key).toString('hex')
      var prefix = dk.slice(0, 2) + '/' + dk.slice(2, 4) + '/' + dk.slice(4) + '/'
  
      return function (name) {
        return self.storage.feeds(prefix + name)
      }
    }
docs: copied from hypercore-archiver.prototype._add()