code: boolean remove(RowCursor cursor)
    {
      int rowHead = _rowHead;
      int blobTail = _blobTail;
      
      rowHead -= cursor.removeLength();
  
      if (rowHead < blobTail) {
        return false;
      }
      
      byte []buffer = _buffer;
      
      // buffer[rowHead] = REMOVE;
      
      cursor.getRemove(buffer, rowHead);
      // cursor.getKey(buffer, rowHead + ColumnState.LENGTH);
      
      rowHead(rowHead);
      
      validateBlock(cursor.row());    
      
      return true;
    }
docs: Removes a key by adding a remove entry to the row.
  
  The remove is represented as a delta entry so checkpoints can be
  written asynchronously.
  
  @return false if the new record cannot fit into the block.