How can EnumMapSerializer work with nested EnumMaps?

[whipit]

This is a feature request, not a bug.

If I have a nested map like so EnumMap<K1, EnumMap<K2, V>>, how can the EnumMapSerializer be modified to work with it?

At present, it doesn't quite work since the value of the top-level map is (de)serialized as an object instead of as another EnumMap.

[Mr14huashao]

PR can't pass CI, but test case :
@SuppressWarnings({"unchecked", "rawtypes"})
@test
public void testEnumMapNest() throws Exception {
_kryo.register(HashSet.class);
_kryo.register(Vipers.class);
_kryo.register(Colors.class);
_kryo.register(EnumMap.class, new EnumMapSerializer());

	final Set<String> mambaAka = new HashSet<String>();
	final Set<String> papaAka = new HashSet<>();
	mambaAka.add("Beatrix Kiddo");
	mambaAka.add("The Bride");
	papaAka.add("Good Job");
	papaAka.add("There is Great");

	_original.put(Vipers.BLACK_MAMBA, mambaAka);
	_original.put(Vipers.SIDEWINDER, papaAka);
	_newTempMap.put(Vipers.COPPERHEAD, _original);

	final File outputFile = File.createTempFile("input_file", "dat");
	try (final Output output = new Output(new FileOutputStream(outputFile))) {
		_kryo.writeObject(output, _newTempMap);
		output.flush();
		output.close();
		final Input input = new Input(new FileInputStream(outputFile));
		final EnumMap tEnumMap = _kryo.readObject(input, EnumMap.class);
		input.close();
		Assert.assertEquals(_newTempMap, tEnumMap);
	}
}