code: @Override
    public FilterSupportStatus isFilterSupported(
        FilterAdapterContext context, KeyOnlyFilter filter) {
      // We don't support replacing the value of a stripped cell with
      // the its length (8-byte-big-endian). The KeyOnlyFilter supports this
      // via a constructor parameter that is not exposed via a getLengthAsValue().
      // In order to find out if this constructor parameter was set,
      // we perform a test transformation. If the test transformation
      // has a cell value length that is not 0 bytes, we know the
      // unsupported constructor param was passed:
      if (filter.transformCell(TEST_CELL).getValueLength() != 0) {
        return FilterSupportStatus.newNotSupported(
            "KeyOnlyFilters with lenAsVal = true are not supported");
      }
      return FilterSupportStatus.SUPPORTED;
    }
docs: {@inheritDoc}