@@ -1,7 +1,6 @@

 package utils

 import (

-	"bytes"

 	"io"

 	"net/http"

 	"strings"

@@ -15,11 +14,13 @@ type VersionInfo interface {

 }

 func validVersion(version VersionInfo) bool {

-	stopChars := " \t\r\n/"

-	if strings.ContainsAny(version.Name(), stopChars) {

+	const stopChars = " \t\r\n/"

+	name := version.Name()

+	vers := version.Version()

+	if len(name) == 0 || strings.ContainsAny(name, stopChars) {

 		return false

 	}

-	if strings.ContainsAny(version.Version(), stopChars) {

+	if len(vers) == 0 || strings.ContainsAny(vers, stopChars) {

 		return false

 	}

 	return true

@@ -36,27 +37,18 @@ func appendVersions(base string, versions ...VersionInfo) string {

 		return base

 	}

-	var buf bytes.Buffer

+	verstrs := make([]string, 0, 1+len(versions))

 	if len(base) > 0 {

-		buf.Write([]byte(base))

+		verstrs = append(verstrs, base)

 	}

 	for _, v := range versions {

-		name := []byte(v.Name())

-		version := []byte(v.Version())

-

-		if len(name) == 0 || len(version) == 0 {

-			continue

-		}

 		if !validVersion(v) {

 			continue

 		}

-		buf.Write([]byte(v.Name()))

-		buf.Write([]byte("/"))

-		buf.Write([]byte(v.Version()))

-		buf.Write([]byte(" "))

+		verstrs = append(verstrs, v.Name()+"/"+v.Version())

 	}

-	return buf.String()

+	return strings.Join(verstrs, " ")

 }

 // HTTPRequestDecorator is used to change an instance of