Add support for Unix domain datagram sockets when using native epoll/kqueue transport

[vietj]

Now possible in Netty : https://github.com/netty/netty/pull/11423

[meoyawn]

do I understand correctly that this is not possible in 4.4.3?

val fdInt = 3
val fdObj = FileDescriptor()
val field = FileDescriptor::class.java.getDeclaredField("fd")
field.isAccessible = true
field.setInt(fdObj, fdInt)

val afSock = FileDescriptorCast.using(fdObj).`as`(org.newsclub.net.unix.AFSocket::class.java)

vertx.createHttpServer()
    .requestHandler(router)
    .listen(io.vertx.core.net.SocketAddress.domainSocketAddress(afSock.))
    .await()

trying to use junixsocket but just can't obtain the String path for domainSocketAddress