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: readwrite_go1_9_test.go
    path of file: ./repos/gitkube/vendor/golang.org/x/net/ipv4
    
    the code of the file until where you have to start completion: // Copyright 2017 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 go1.9

package ipv4_test

import (
	"bytes"
	"fmt"
	"net"
	"runtime"
	"strings"
	"sync"
	"testing"

	"golang.org/x/net/internal/iana"
	"golang.org/x/net/internal/nettest"
	"golang.org/x/net/ipv4"
)

func BenchmarkPacketConnReadWriteUnicast(b *testing.B) {
	switch runtime.GOOS {
	case "js", "nacl", "plan9", "windows":
		b.Skipf("not supported on %s", runtime.GOOS)
	}

	payload := []byte("HELLO-R-U-THERE")
	iph, err := (&ipv4.Header{
		Version:  ipv4.Version,
		Len:      ipv4.H
    
func BenchmarkPacketConnReadWriteUnicast(b *testing.B) {
	switch runtime.GOOS {
	case "js", "nacl", "plan9", "windows":
		b.Skipf("not supported on %s", runtime.GOOS)
	}

	payload := []byte("HELLO-R-U-THERE")
	iph, err := (&ipv4.Header{
		Version:  ipv4.Version,
		Len:      ipv4.HeaderLen,
		TotalLen: ipv4.HeaderLen + len(payload),
		TTL:      1,
		Protocol: iana.ProtocolReserved,
		Src:      net.IPv4(192, 0, 2, 1),
		Dst:      net.IPv4(192, 0, 2, 254),
	}).Marshal()
	if err != nil {
		b.Fatal(err)
	}
	greh := []byte{0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00}
	datagram := append(greh, append(iph, payload...)...)
	bb := make([]byte, 128)
	cm := ipv4.ControlMessage{
		Src: net.IPv4(127, 0, 0, 1),
	}
	if ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagLoopback); ifi != nil {
		cm.IfIndex = ifi.Index
	}

	b.Run("UDP", func(b *testing.B) {
		c, err := nettest.NewLocalPacketListener("udp4")
		if err != nil {
			b.Skipf("not supported on %s/%s: %v", runtime.GOOS, runtime.GOARCH, err)
		}
		defer c.Close()
		p := ipv4.NewPacketConn(c)
		dst := c.LocalAddr()
		cf := ipv4.FlagTTL | ipv4.FlagInterface
		if err := p.SetControlMessage(cf, true); err != nil {
			b.Fatal(err)
		}
		wms := []ipv4.Message{
			{
				Buffers: [][]byte{payload},
				Addr:    dst,
				OOB:     cm.Marshal(),
			},
		}
		rms := []ipv4.Message{
			{
				Buffers: [][]byte{bb},
				OOB:     ipv4.NewControlMessage(cf),
			},
		}
		b.Run("Net", func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				if _, err := c.WriteTo(payload, dst); err != nil {
					b.Fatal(err)
				}
				if _, _, err := c.ReadFrom(bb); err != nil {
					b.Fatal(err)
				}
			}
		})
		b.Run("ToFrom", func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				if _, err := p.WriteTo(payload, &cm, dst); err != nil {
					b.Fatal(err)
				}
				if _, _, _, err := p.ReadFrom(bb); err != nil {
					b.Fatal(err)
				}
			}
		})
		b.Run("Batch", func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				if _, err := p.WriteBatch(wms, 0); err != nil {
					b.Fatal(err)
				}
				if _, err := p.ReadBatch(rms, 0); err != nil {
					b.Fatal(err)
				}
			}
		})
	})
	b.Run("IP", func(b *testing.B) {
		switch runtime.GOOS {
		case "netbsd":
			b.Skip("need to configure gre on netbsd")
		case "openbsd":
			b.Skip("net.inet.gre.allow=0 by default on openbsd")
		}

		c, err := net.ListenPacket(fmt.Sprintf("ip4:%d", iana.ProtocolGRE), "127.0.0.1")
		if err != nil {
			b.Skipf("not supported on %s/%s: %v", runtime.GOOS, runtime.GOARCH, err)
		}
		defer c.Close()
		p := ipv4.NewPacketConn(c)
		dst := c.LocalAddr()
		cf := ipv4.FlagTTL | ipv4.FlagInterface
		if err := p.SetControlMessage(cf, true); err != nil {
			b.Fatal(err)
		}
		wms := []ipv4.Message{
			{
				Buffers: [][]byte{datagram},
				Addr:    dst,
				OOB:     cm.Marshal(),
			},
		}
		rms := []ipv4.Message{
			{
				Buffers: [][]byte{bb},
				OOB:     ipv4.NewControlMessage(cf),
			},
		}
		b.Run("Net", func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				if _, err := c.WriteTo(datagram, dst); err != nil {
					b.Fatal(err)
				}
				if _, _, err := c.ReadFrom(bb); err != nil {
					b.Fatal(err)
				}
			}
		})
		b.Run("ToFrom", func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				if _, err := p.WriteTo(datagram, &cm, dst); err != nil {
					b.Fatal(err)
				}
				if _, _, _, err := p.ReadFrom(bb); err != nil {
					b.Fatal(err)
				}
			}
		})
		b.Run("Batch", func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				if _, err := p.WriteBatch(wms, 0); err != nil {
					b.Fatal(err)
				}
				if _, err := p.ReadBatch(rms, 0); err != nil {
					b.Fatal(err)
				}
			}
		})
	})
}