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: clientauth.go
    path of file: ./repos/kubeedge/vendor/golang.org/x/oauth2/google/internal/externalaccount
    
    the code of the file until where you have to start completion: // Copyright 2020 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.

package externalaccount

imp
    
func (c *clientAuthentication) InjectAuthentication(values url.Values, headers http.Header) {
	if c.ClientID == "" || c.ClientSecret == "" || values == nil || headers == nil {
		return
	}

	switch c.AuthStyle {
	case oauth2.AuthStyleInHeader: // AuthStyleInHeader corresponds to basic authentication as defined in rfc7617#2
		plainHeader := c.ClientID + ":" + c.ClientSecret
		headers.Add("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(plainHeader)))
	case oauth2.AuthStyleInParams: // AuthStyleInParams corresponds to request-body authentication with ClientID and ClientSecret in the message body.
		values.Set("client_id", c.ClientID)
		values.Set("client_secret", c.ClientSecret)
	case oauth2.AuthStyleAutoDetect:
		values.Set("client_id", c.ClientID)
		values.Set("client_secret", c.ClientSecret)
	default:
		values.Set("client_id", c.ClientID)
		values.Set("client_secret", c.ClientSecret)
	}
}