You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: syscall_unix_test.go
    path of file: ./repos/go-starter-kit/vendor/golang.org/x/sys/unix
    
    the code of the file until where you have to start completion: // Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build darwin dragonfly freebsd linux netbsd openbsd solaris

package unix_test

import (
	"flag"
	"fmt"
	"io/ioutil"
	"net"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"testing"
	"time"

	"golang.org/x/s
    
func passFDChild() {
	defer os.Exit(0)

	// Look for our fd. It should be fd 3, but we work around an fd leak
	// bug here (http://golang.org/issue/2603) to let it be elsewhere.
	var uc *net.UnixConn
	for fd := uintptr(3); fd <= 10; fd++ {
		f := os.NewFile(fd, "unix-conn")
		var ok bool
		netc, _ := net.FileConn(f)
		uc, ok = netc.(*net.UnixConn)
		if ok {
			break
		}
	}
	if uc == nil {
		fmt.Println("failed to find unix fd")
		return
	}

	// Make a file f to send to our parent process on uc.
	// We make it in tempDir, which our parent will clean up.
	flag.Parse()
	tempDir := flag.Arg(0)
	f, err := ioutil.TempFile(tempDir, "")
	if err != nil {
		fmt.Printf("TempFile: %v", err)
		return
	}

	f.Write([]byte("Hello from child process!\n"))
	f.Seek(0, 0)

	rights := unix.UnixRights(int(f.Fd()))
	dummyByte := []byte("x")
	n, oobn, err := uc.WriteMsgUnix(dummyByte, rights, nil)
	if err != nil {
		fmt.Printf("WriteMsgUnix: %v", err)
		return
	}
	if n != 1 || oobn != len(rights) {
		fmt.Printf("WriteMsgUnix = %d, %d; want 1, %d", n, oobn, len(rights))
		return
	}
}