raddr := fd.addrFunc()(rsa)
	fd.net = laddr.Network()
	if err := fd.init(); err != nil {
		fd.Close()
		return nil, err
	}
	fd.setAddr(laddr, raddr)
	return fd, nil
}

func fileConn(f *os.File) (Conn, error) {
	fd, err := newFileFD(f)
	if err != nil {
		return nil, err
	}
	switch fd.laddr.(type) {
	case *TCPAddr:

	}
	dir := netdir + "/" + comp[1] + "/" + name
	laddr, err := readPlan9Addr(comp[1], dir+"/local")
	if err != nil {
		return nil, err
	}
	return newFD(comp[1], name, nil, ctl, nil, laddr, nil)
}

func fileConn(f *os.File) (Conn, error) {
	fd, err := newFileFD(f)
	if err != nil {
		return nil, err
	}
	if !fd.ok() {
		return nil, syscall.EINVAL
	}

	fd.data, err = os.OpenFile(fd.dir+"/data", os.O_RDWR, 0)

func startTestSocketPeer(t testing.TB, conn Conn, op string, chunkSize, totalSize int) (func(t testing.TB), error) {
	t.Helper()

	if runtime.GOOS == "windows" {
		// TODO(panjf2000): Windows has not yet implemented FileConn,
		//		remove this when it's implemented in https://go.dev/issues/9503.
		t.Fatalf("startTestSocketPeer is not supported on %s", runtime.GOOS)
	}

	f, err := conn.(interface{ File() (*os.File, error) }).File()

		b.Fatalf("expected %d copied bytes, but got %d", dataSize, n)
	}

	cancel()
}

func BenchmarkSendFile(b *testing.B) {
	if runtime.GOOS == "windows" {
		// TODO(panjf2000): Windows has not yet implemented FileConn,
		//		remove this when it's implemented in https://go.dev/issues/9503.
		b.Skipf("skipping on %s", runtime.GOOS)
	}

	b.Run("file-to-tcp", func(b *testing.B) { benchmarkSendFile(b, "tcp") })

		{"Dialer.LocalAddr", Field, 1},
		{"Dialer.Resolver", Field, 8},
		{"Dialer.Timeout", Field, 1},
		{"ErrClosed", Var, 16},
		{"ErrWriteToConnected", Var, 0},
		{"Error", Type, 0},
		{"FileConn", Func, 0},
		{"FileListener", Func, 0},
		{"FilePacketConn", Func, 0},
		{"FlagBroadcast", Const, 0},
		{"FlagLoopback", Const, 0},
		{"FlagMulticast", Const, 0},
		{"FlagPointToPoint", Const, 0},