code: function (localId, bucketSize) {
      if (!(localId instanceof Id))
          throw new Error('id must be a valid identifier');
      this._bucketSize = bucketSize;
      this._root = new Bucket(bucketSize);
      Object.defineProperty(this, 'id', {value: localId});
  }
docs: Associate Kademlia IDs with their endpoints. `localId` must be the ID of the local node, more close contacts are effectively stored than far contacts.