docs: VoltTable semiDeepCopy() {
          assert(verifyTableInvariants());
          // share the immutable metadata if it's present for tests
          final VoltTable cloned = new VoltTable(m_extraMetadata);
          cloned.m_colCount = m_colCount;
          cloned.m_rowCount = m_rowCount;
          cloned.m_rowStart = m_rowStart;
  
          cloned.m_buffer = m_buffer.duplicate();
          cloned.m_activeRowIndex = m_activeRowIndex;
          cloned.m_hasCalculatedOffsets = m_hasCalculatedOffsets;
          cloned.m_memoizedBufferOffset = m_memoizedBufferOffset;
          cloned.m_memoizedRowOffset = m_memoizedRowOffset;
          cloned.m_offsets = m_offsets == null ? null : m_offsets.clone();
          cloned.m_position = m_position;
          cloned.m_schemaString = m_schemaString == null ? null : m_schemaString.clone();
          cloned.m_wasNull = m_wasNull;
  
          // make the new table read only
          cloned.m_readOnly = true;
  
          assert(verifyTableInvariants());
          assert(cloned.verifyTableInvariants());
          return cloned;
      }