Motivation:
There are use cases when Unix domain datagram sockets are needed for communication. This PR adds such support for Epoll/KQueue.
Modification:
- Expose Channel, Config and Packet interfaces/classes for Unix domain datagram sockets. All interfaces/classes are in `transport-native-unix-common` module in order to be available for KQueue and Epoll implementations
- Add JNI code for Unix domain datagram sockets
- Refactor `DatagramUnicastTest` so that it can be used for testing also Unix domain datagram sockets
- Add Unix domain datagram sockets implementation for KQueue transport
- Add Unix domain datagram sockets implementation for Epoll transport
Result:
Fixes#6737
3f9a5f50be