docs: public final BigDecimal getDecimalAsBigDecimal(int columnIndex) {
          validateColumnType(columnIndex, VoltType.DECIMAL);
          final int position = m_buffer.position();
          m_buffer.position(getOffset(columnIndex));
          final BigDecimal bd = VoltDecimalHelper.deserializeBigDecimal(m_buffer);
          m_buffer.position(position);
          m_wasNull = bd == null ? true : false;
          return bd;
      }