@Override
    public String getValue(String key) {
      Bytes rval = values.get(new Bytes(Bytes.toBytes(key)));
      return rval == null ? null : Bytes.toString(rval.get(), rval.getOffset(), rval.getLength());
    }
Constructor. Makes a deep copy of the supplied descriptor. TODO: make this private after the
HCD is removed.
@param desc The descriptor.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/ColumnFamilyDescriptorBuilder.java