@Override
    public byte[] getValue(byte[] key) {
      Bytes value = values.get(new Bytes(key));
      return value == null ? null : value.get();
    }
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