// Add column metadata
        if (extractColumnMetadata && headers != null) {
            extractData.putValues("columns", headers);
            extractData.putValue("column_count", String.valueOf(headers.length));
        }

        extractData.putValue("row_count", String.valueOf(rows.size()));

        return extractData;
    }

    /**

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] rowCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final int[] columnCounts;

  @SuppressWarnings("Immutable") // We don't modify this after construction.
  private final @Nullable V[][] values;

  // For each cell in iteration order, the index of that cell's row key in the row key list.