code: @Override
    public ApiFuture<Void> add(RowMutation rowMutation) {
      return ApiFutureUtil.transformAndAdapt(delegate.add(rowMutation.toBulkProto(requestContext).getEntries(0)),
          new Function<MutateRowResponse, Void>() {
            @Override
            public Void apply(MutateRowResponse response) {
              return null;
            }
          });
    }
docs: {@inheritDoc}