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: sys_posix.go
    path of file: ./repos/sealer/vendor/golang.org/x/net/internal/socket
    
    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.

//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || windows || zos
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris windows zos

package socket

import (
	"encoding/binary"
	"errors"
	"net"
	"runtime"
	"strconv"
	"sync"
	"time"
)

// marshalInetAddr writes a in sockaddr format into the buffer b.
// The buffer must be sufficiently large (sizeofSoc
    
func (zc *ipv6ZoneCache) update(ift []net.Interface, force bool) (updated bool) {
	zc.Lock()
	defer zc.Unlock()
	now := time.Now()
	if !force && zc.lastFetched.After(now.Add(-60*time.Second)) {
		return false
	}
	zc.lastFetched = now
	if len(ift) == 0 {
		var err error
		if ift, err = net.Interfaces(); err != nil {
			return false
		}
	}
	zc.toIndex = make(map[string]int, len(ift))
	zc.toName = make(map[int]string, len(ift))
	for _, ifi := range ift {
		zc.toIndex[ifi.Name] = ifi.Index
		if _, ok := zc.toName[ifi.Index]; !ok {
			zc.toName[ifi.Index] = ifi.Name
		}
	}
	return true
}