code: @Override
    public ApiFuture<Void> mutateRowAsync(RowMutation rowMutation) {
      ListenableFuture<MutateRowResponse> response =
          delegate.mutateRowAsync(rowMutation.toProto(requestContext));
      return  ApiFutureUtil.transformAndAdapt(response, new Function<MutateRowResponse, Void>() {
        @Nullable
        @Override
        public Void apply(@Nullable MutateRowResponse mutateRowResponse) {
          return null;
        }
      });
    }
docs: {@inheritDoc}