@Override
    public KeepDeletedCells getKeepDeletedCells() {
      return getStringOrDefault(KEEP_DELETED_CELLS_BYTES, KeepDeletedCells::getValue,
        DEFAULT_KEEP_DELETED);
    }
Set the inMemory flag
@param inMemory True if we are to favor keeping all values for this column family in the
                HRegionServer cache
@return this (for chained invocation)
hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptorBuilder.java