fails:UNIXSocket#pair if the write end is closed then the other side can read past EOF without blocking
fails:UNIXSocket#pair closing the write end ensures that the other side can read until EOF
fails:UNIXSocket#pair returns a pair of connected sockets
fails:UNIXSocket#pair returns sockets with no name
fails:UNIXSocket#pair returns sockets with no address
fails:UNIXSocket#pair returns sockets with no peeraddr
