RunEndEncoded type not supported in IPC reader or writer

[paleolimbot]

As reported here: paleolimbot/duckdb-nanoarrow#40

[paleolimbot]

The schema encoding is here:

arrow-nanoarrow/src/nanoarrow/ipc/encoder.c

Lines 329 to 336 in 04e7521

	case NANOARROW_TYPE_DICTIONARY:
	ArrowErrorSet(error, "IPC encoding of dictionary types unsupported");
	return ENOTSUP;
	default:
	ArrowErrorSet(error, "Expected a valid enum ArrowType value but found %d",
	schema_view->type);
	return EINVAL;

The decoding is here:

arrow-nanoarrow/src/nanoarrow/ipc/decoder.c

Lines 817 to 822 in 04e7521

	case ns(Type_Union):
	return ArrowIpcDecoderSetTypeUnion(schema, ns(Field_type_get(field)), n_children,
	error);
	default:
	ArrowErrorSet(error, "Unrecognized Field type with value %d", type_type);
	return EINVAL;

I think that run-end encoding is pretty straightforward (there are no parameters, the array just has two children).