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: config.go
    path of file: ./repos/comply/vendor/github.com/docker/go-connections/tlsconfig
    
    the code of the file until where you have to start completion: // Package tlsconfig provides primitives to retrieve secure-enough TLS configurations for both clients and servers.
//
// As a reminder from https://golang.org/pkg/crypto/tls/#Config:
//	A Config structure is used to configure a TLS client or server. After one has been passed to a TLS function it must not be modified.
//	A Config may be reused; the tls package will also not modify it.
package tlsconfig

import (
	"crypto/tls"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"io/ioutil"
	"os"

	"github.com/pkg/errors"
)

// Options represents the information needed to create client and server TLS configurations.
type Options struct {
	CAFile string

	// If either CertFile or KeyFile is empty, Client() will not load them
	// preventing the client from authenticating to the server.
	// However, Server() requires them and will error out if they are empty.
	CertFile string
	KeyFile
    
func Server(options Options) (*tls.Config, error) {
	tlsConfig := ServerDefault()
	tlsConfig.ClientAuth = options.ClientAuth
	tlsCert, err := tls.LoadX509KeyPair(options.CertFile, options.KeyFile)
	if err != nil {
		if os.IsNotExist(err) {
			return nil, fmt.Errorf("Could not load X509 key pair (cert: %q, key: %q): %v", options.CertFile, options.KeyFile, err)
		}
		return nil, fmt.Errorf("Error reading X509 key pair (cert: %q, key: %q): %v. Make sure the key is not encrypted.", options.CertFile, options.KeyFile, err)
	}
	tlsConfig.Certificates = []tls.Certificate{tlsCert}
	if options.ClientAuth >= tls.VerifyClientCertIfGiven && options.CAFile != "" {
		CAs, err := certPool(options.CAFile, options.ExclusiveRootPools)
		if err != nil {
			return nil, err
		}
		tlsConfig.ClientCAs = CAs
	}

	if err := adjustMinVersion(options, tlsConfig); err != nil {
		return nil, err
	}

	return tlsConfig, nil
}