// sockaddr type that implements syscall.Sockaddr
	// interface. It returns a nil interface when the address is
	// nil.
	sockaddr(family int) (syscall.Sockaddr, error)

	// toLocal maps the zero address to a local system address (127.0.0.1 or ::1)
	toLocal(net string) sockaddr
}

func (fd *netFD) addrFunc() func(syscall.Sockaddr) Addr {
	switch fd.family {
	case syscall.AF_INET, syscall.AF_INET6:
		switch fd.sotype {

		pp := l.getPayload(i)
		return pp.name
	}
	r, li := l.toLocal(i)
	if r == nil {
		return "?"
	}
	return r.Sym(li).Name(r.Reader)
}

// Returns the version of the i-th symbol.
func (l *Loader) SymVersion(i Sym) int {
	if l.IsExternal(i) {
		pp := l.getPayload(i)
		return pp.ver
	}
	r, li := l.toLocal(i)
	return int(abiToVer(r.Sym(li).ABI(), r.version))
}

	case <-ctx.Done():
		return nil, mapErr(ctx.Err())
	}
}

func dialPlan9Blocking(ctx context.Context, net string, laddr, raddr Addr) (fd *netFD, err error) {
	if isWildcard(raddr) {
		raddr = toLocal(raddr, net)
	}
	f, dest, proto, name, err := startPlan9(ctx, net, raddr)
	if err != nil {
		return nil, err
	}
	if la := plan9LocalAddr(laddr); la == "" {
		err = hangupCtlWrite(ctx, proto, f, "connect "+dest)

	}
	return syscall.AF_INET6
}

func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {
		return nil, nil
	}
	return ipToSockaddr(family, a.IP, 0, a.Zone)
}

func (a *IPAddr) toLocal(net string) sockaddr {
	return &IPAddr{loopbackIP(net), a.Zone}
}

func (c *IPConn) readFrom(b []byte) (int, *IPAddr, error) {
	// TODO(cw,rsc): consider using readv if we know the family

	return syscall.AF_UNIX
}

func (a *UnixAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {
		return nil, nil
	}
	return &syscall.SockaddrUnix{Name: a.Name}, nil
}

func (a *UnixAddr) toLocal(net string) sockaddr {
	return a
}

func (c *UnixConn) readFrom(b []byte) (int, *UnixAddr, error) {
	var addr *UnixAddr
	n, sa, err := c.fd.readFrom(b)
	switch sa := sa.(type) {
	case *syscall.SockaddrUnix:

	return syscall.AF_INET6
}

func (a *TCPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {
		return nil, nil
	}
	return ipToSockaddr(family, a.IP, a.Port, a.Zone)
}

func (a *TCPAddr) toLocal(net string) sockaddr {
	return &TCPAddr{loopbackIP(net), a.Port, a.Zone}
}

func (c *TCPConn) readFrom(r io.Reader) (int64, error) {
	if n, err, handled := spliceFrom(c.fd, r); handled {
		return n, err
	}

	return syscall.AF_INET6
}

func (a *UDPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {
		return nil, nil
	}
	return ipToSockaddr(family, a.IP, a.Port, a.Zone)
}

func (a *UDPAddr) toLocal(net string) sockaddr {
	return &UDPAddr{loopbackIP(net), a.Port, a.Zone}
}

func (c *UDPConn) readFrom(b []byte, addr *UDPAddr) (int, *UDPAddr, error) {
	var n int
	var err error
	switch c.fd.family {

	switch runtime.GOOS {
	case "aix", "windows", "openbsd", "js", "wasip1":
		if mode == "dial" && raddr.isWildcard() {
			raddr = raddr.toLocal(net)
		}
	}
	family, ipv6only := favoriteAddrFamily(net, laddr, raddr, mode)
	return socket(ctx, net, family, sotype, proto, ipv6only, laddr, raddr, ctrlCtxFn)
}

echo Must run make.bat from Go...

if...