@Override
      public KeyValue apply(ExtendedCell arg0) {
        return KeyValueUtil.ensureKeyValue(arg0);
      }
@return <code>cell</code> if it is an object of class {@link KeyValue} else we will return a
        new {@link KeyValue} instance made from <code>cell</code> Note: Even if the cell is an
        object of any of the subclass of {@link KeyValue}, we will create a new
        {@link KeyValue} object wrapping same buffer. This API is used only with MR based tools
        which expect the type to be exactly KeyValue. That is the reason for doing this way.
@deprecated without any replacement.
hbase-common/src/main/java/org/apache/hadoop/hbase/KeyValueUtil.java