[java.nio.ByteOrder] is converted from a class to an `Enum` to allow it to be used in expression switch and elsewhere the language can dispatch on an `Enum`, for example in `switch`.
The `ByteOrder` enum is fully compatible with the class implementation.
The `BIG_ENDIAN`, `LITTLE_ENDIAN`, and [ByteOrder.nativeOrder()] values remain a simple and effective way to test for the byte order.