FromFile attempts to create a [net.UnixConn] from a file.

NewSocketpair creates a unix socket pair, returning the halves as [*net.UnixConn]s.

ReadWithFDs reads data and associated fds.

WriteWithFDs performs a write that may also send associated FDs.

SocketTypeDatagram indicates that the socket type should be a unix datagram.

SocketTypeStream indicates that the socket type should be a streaming socket.

SocketType encodes the type of desired socket (datagram or stream).