+ assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![]);
+
+ let mut features = ChannelFeatures::empty();
+ features.set_unknown_feature_required();
+ features.set_custom_bit(123456786).unwrap();
+ assert!(features.requires_unknown_bits());
+ assert!(features.supports_unknown_bits());
+ assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456786, 123456788]);
+
+ let mut limiter = ChannelFeatures::empty();
+ limiter.set_unknown_feature_optional();
+ assert_eq!(features.required_unknown_bits_from(&limiter), vec![123456786]);