code: @Override
    public List<KeyOffset> sampleRowKeys(String tableId) {
      String fullTableName = NameUtil
          .formatTableName(requestContext.getProjectId(), requestContext.getInstanceId(), tableId);
      SampleRowKeysRequest requestProto = SampleRowKeysRequest.newBuilder()
          .setTableName(fullTableName)
          .build();
      List<SampleRowKeysResponse> responseProto = delegate.sampleRowKeys(requestProto);
      ImmutableList.Builder<KeyOffset> keyOffsetBuilder =
          ImmutableList.builderWithExpectedSize(responseProto.size());
      for(SampleRowKeysResponse rowKeys : responseProto){
        keyOffsetBuilder.add(KeyOffset.create(rowKeys.getRowKey(), rowKeys.getOffsetBytes()));
      }
  
      return keyOffsetBuilder.build();
    }
docs: {@inheritDoc}