return sd.dialTCP(ctx, laddr, raddr)
}

func (sl *sysListener) listenMPTCP(ctx context.Context, laddr *TCPAddr) (*TCPListener, error) {
	return sl.listenTCP(ctx, laddr)
}

func isUsingMultipathTCP(fd *netFD) bool {
	return false

			return dial, nil
		}
	}

	// Fallback to listenTCP if Multipath TCP isn't supported on this operating
	// system. But also fallback in case of any error with MPTCP.
	//
	// Possible MPTCP specific error: ENOPROTOOPT (sysctl net.mptcp.enabled=0)
	// But just in case MPTCP is blocked differently (SELinux, etc.), just
	// retry with "plain" TCP.
	return sl.listenTCP(ctx, laddr)
}

		return err
	}
	return nil
}

func (ln *TCPListener) file() (*os.File, error) {
	f, err := ln.dup()
	if err != nil {
		return nil, err
	}
	return f, nil
}

func (sl *sysListener) listenTCP(ctx context.Context, laddr *TCPAddr) (*TCPListener, error) {
	fd, err := listenPlan9(ctx, sl.network, laddr)
	if err != nil {
		return nil, err
	}
	return &TCPListener{fd: fd, lc: sl.ListenConfig}, nil

	switch runtime.GOOS {
	case "plan9":
		t.Skipf("not supported on %s", runtime.GOOS)
	}

	la, err := ResolveTCPAddr("tcp4", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	ln, err := ListenTCP("tcp4", la)
	if err != nil {
		t.Fatal(err)
	}
	defer ln.Close()
	ln.Addr()
	mustSetDeadline(t, ln.SetDeadline, 30*time.Nanosecond)

	if c, err := ln.Accept(); err != nil {
		if !err.(Error).Timeout() {

	return ln.fd.Close()
}

func (ln *TCPListener) file() (*os.File, error) {
	f, err := ln.fd.dup()
	if err != nil {
		return nil, err
	}
	return f, nil
}

func (sl *sysListener) listenTCP(ctx context.Context, laddr *TCPAddr) (*TCPListener, error) {
	return sl.listenTCPProto(ctx, laddr, 0)
}

func (sl *sysListener) listenTCPProto(ctx context.Context, laddr *TCPAddr, proto int) (*TCPListener, error) {