code: <T> List<T> query(Query<T> query) throws IOException {
      return call(() -> ImmutableList.copyOf(rw.run(query)));
    }
docs: Only use this method if the results are small enough that gathering them in list is acceptable.
  Otherwise use {@link #query(Query, IOConsumer)}.
  @see DatastoreReaderWriter#run(Query)
  @throws IOException if the underlying client throws {@link DatastoreException}