public ModifyableColumnFamilyDescriptor setValue(String key, String value) {
      return setValue(toBytesOrNull(key, Bytes::toBytes), toBytesOrNull(value, Bytes::toBytes));
    }
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