@Override
      public ExtendedCell current() {
        return this.currentCell;
      }
Flatten the map of cells out under the ExtendedCellScanner
@param map Map of Cell Lists; for example, the map of families to ExtendedCells that is used
           inside Put, etc., keeping Cells organized by family.
@return ExtendedCellScanner interface over <code>cellIterable</code>
hbase-common/src/main/java/org/apache/hadoop/hbase/PrivateCellUtil.java